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Cao H, Wang J, Qi X. Characterisation of arsenic levels in acid-treated arsenic-containing sludge after steel slag-fly ash gel curing. ENVIRONMENTAL TECHNOLOGY 2024:1-14. [PMID: 38471045 DOI: 10.1080/09593330.2024.2328153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/08/2023] [Indexed: 03/14/2024]
Abstract
Arsenic-containing sludge (ABG) is a common hazardous waste in the metallurgical industry and poses a serious threat to environmental safety. However, its instability and mobility have a significant impact on the environment. Traditional curing methods are time-consuming and costly, often resulting in incomplete curing. In this study, we introduce a curing/stabilisation method with a steel slag-fly ash gel material after ABG acid treatment. The toxic leaching of arsenic from ABG was reduced to 220 mg/kg by treating the sludge with acids (H2SO4-H3PO4) at different solid-to-liquid ratios. Afterward, H2O2 was added to oxidise As(III) to As(V). The ABG was cured/stabilised using an alkali-activated steel slag-fly ash gel material. The cured product exhibited optimal arsenic fixation under an ABG/steel slag/fly ash mass ratio of 1:4:2, a curing temperature of 60°C, a curing time of 20 h, and an ambient pH of 12.5. Under these conditions, steel slag-fly ash facilitated Ca-As precipitation, resulting in a hydration reaction that produced C-S-H gel. Additionally, the reaction generated calcium hydroxide, calcium and iron pyroxene, silica, and iron ferrite, which adsorbed part of the free arsenic, completing the curing of the acid-treated ABG and stabilising arsenic leaching toxicity. The leaching of arsenic in the ABG was much lower than the Chinese 'Hazardous Wastes Leaching Toxicity Identification Standard' (GB5085.3-2007) (5 mg/L), with an arsenic curing rate exceeding 99%. The mechanism of arsenic solidification involves the combined effects of chemical precipitation, physical encapsulation, and adsorption. Collectively, our findings demonstrated that the use of steel slag-fly ash gel as a functional material for ABG curing holds considerable environmental and economic benefits. Therefore, this study provides theoretical guidance and provides insights into the experimental feasibility of ABG treatment.
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Affiliation(s)
- Hengyi Cao
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, People's Republic of China
| | - Jianhua Wang
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, People's Republic of China
| | - Xianjin Qi
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, People's Republic of China
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He B, Zhu X, Cang Z, Liu Y, Lei Y, Chen Z, Wang Y, Zheng Y, Cang D, Zhang L. Interpretation and Prediction of the CO 2 Sequestration of Steel Slag by Machine Learning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17940-17949. [PMID: 37624988 DOI: 10.1021/acs.est.2c06133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
The utilization of steel slag for CO2 sequestration is an effective way to reduce carbon emissions. The reactivity of steel slag in CO2 sequestration depends mainly on material and process parameters. However, there are many puzzles in regard to practical applications due to the different evaluations of process parameters and the lack of investigation of material parameters. In this study, 318 samples were collected to investigate the interactive influence of 12 factors on the carbonation reactivity of steel slag by machine learning with SHapley Additive exPlanations (SHAP). Multilayer perceptron (MLP), random forest, and support vector regression models were built to predict the slurry-phase CO2 sequestration of steel slag. The MLP model performed well in terms of prediction ability and generalization with comprehensive interpretability. The SHAP results showed that the impact of the process parameters was greater than that of the material parameters. Interestingly, the iron ore phase of steel slag was revealed to have a positive effect on steel slag carbonation by SHAP analysis. Combined with previous literature, the carbonation mechanism of steel slag was proposed. Quantitative analysis based on SHAP indicated that steel slag had good carbonation reactivity when the mass fractions of "CaO + MgO", "SiO2 + Al2O3", "Fe2O3", and "MnO" varied from 50-55%, 10-15%, 30-35%, and <5%, respectively.
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Affiliation(s)
- Bingyang He
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xingyu Zhu
- Department of Electronic and Information Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong SAR 999077, China
| | - Zhizhi Cang
- Beijing Building Materials Academy of Sciences Research, Beijing 100041, PR China
| | - Yang Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuxin Lei
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhaohou Chen
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yanlin Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yongchao Zheng
- Beijing Building Materials Academy of Sciences Research, Beijing 100041, PR China
| | - Daqiang Cang
- School of Metallurgy and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Lingling Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
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Abdul F, Iizuka A, Ho HJ, Adachi K, Shibata E. Potential of major by-products from non-ferrous metal industries for CO 2 emission reduction by mineral carbonation: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27898-y. [PMID: 37308624 DOI: 10.1007/s11356-023-27898-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 05/21/2023] [Indexed: 06/14/2023]
Abstract
By-products from the non-ferrous industry are an environmental problem; however, their economic value is high if utilized elsewhere. For example, by-products that contain alkaline compounds can potentially sequestrate CO2 through the mineral carbonation process. This review discusses the potential of these by-products for CO2 reduction through mineral carbonation. The main by-products that are discussed are red mud from the alumina/aluminum industry and metallurgical slag from the copper, zinc, lead, and ferronickel industries. This review summarizes the CO2 equivalent emissions generated by non-ferrous industries and various data about by-products from non-ferrous industries, such as their production quantities, mineralogy, and chemical composition. In terms of production quantities, by-products of non-ferrous industries are often more abundant than the main products (metals). In terms of mineralogy, by-products from the non-ferrous industry are silicate minerals. Nevertheless, non-ferrous industrial by-products have a relatively high content of alkaline compounds, which makes them potential feedstock for mineral carbonation. Theoretically, considering their maximum sequestration capacities (based on their oxide compositions and estimated masses), these by-products could be used in mineral carbonation to reduce CO2 emissions. In addition, this review attempts to identify the difficulties encountered during the use of by-products from non-ferrous industries for mineral carbonation. This review estimated that the total CO2 emissions from the non-ferrous industries could be reduced by up to 9-25%. This study will serve as an important reference, guiding future studies related to the mineral carbonation of by-products from non-ferrous industries.
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Affiliation(s)
- Fakhreza Abdul
- Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, 468-1, Aoba, Aramaki, Aoba-Ku, Sendai, Miyagi, 980-0845, Japan.
- Department of Materials and Metallurgical Engineering, Faculty of Industrial Technology and System Engineering, Institut Teknologi Sepuluh Nopember, Arief Rahman Hakim Street, Surabaya, 60111, Indonesia.
| | - Atsushi Iizuka
- Center for Mineral Processing and Metallurgy, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, Miyagi, 980-8577, Japan
| | - Hsing-Jung Ho
- Center for Mineral Processing and Metallurgy, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, Miyagi, 980-8577, Japan
| | - Ken Adachi
- Center for Mineral Processing and Metallurgy, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, Miyagi, 980-8577, Japan
| | - Etsuro Shibata
- Center for Mineral Processing and Metallurgy, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, Miyagi, 980-8577, Japan
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Krause MJ, Detwiler N, Eades W, Marro D, Schwarber A, Tolaymat T. Understanding landfill gas behavior at elevated temperature landfills. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 165:83-93. [PMID: 37087787 PMCID: PMC10405139 DOI: 10.1016/j.wasman.2023.04.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 05/03/2023]
Abstract
Landfill gas (LFG) wellhead data were compared to understand the range of observations due to unique conditions at five elevated temperature landfills (ETLFs) in the U.S. Correlations of the primary gas ratio, CH4:CO2, show distinct compositional indicators for (1) typical operation, (2) subsurface exothermic reactions (SERs), (3) high moisture content, and (4) air intrusion that can help operators and regulators diagnose conditions across gas extraction wells. ETLFs A, B, D, and E showed similar trends, such as decreasing CH4 and increasing CO2, CO, and H2 that have been previously described. ETLF C uniquely exhibited elevated CH4 and temperatures simultaneously due to carbonation (i.e., CO2 consumption) of a steel slag which was used as alternative daily cover (ADC). At the maximum gas well temperature, T = 82 °C/180 °F, CH4 and CO2 concentrations were 47% and 28%, respectively. At ETLFs A, B, and E, H2 > 50% were regularly observed in affected gas wells for several years. At the five ETLFs, maximum CO concentrations ranged from 1400-16,000 ppmv. Like the analysis of CH4:CO2, it is hypothesized here that H2 (%):CO (ppmv) may infer the types of waste that are thermally degrading. Co-disposal of industrial wastes and MSW and the use of potentially reactive ADCs should remain an important consideration for landfill operators and regulators because of their potential long-term impacts to LFG quality.
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Affiliation(s)
- Max J Krause
- US Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Natalie Detwiler
- Oak Ridge Associated Universities, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - William Eades
- Oak Ridge Associated Universities, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Davin Marro
- Oak Ridge Associated Universities, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Amy Schwarber
- US Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Thabet Tolaymat
- US Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
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Calabrese S, Wild B, Bertagni MB, Bourg IC, White C, Aburto F, Cipolla G, Noto LV, Porporato A. Nano- to Global-Scale Uncertainties in Terrestrial Enhanced Weathering. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15261-15272. [PMID: 36269897 DOI: 10.1021/acs.est.2c03163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Enhanced weathering (EW) is one of the most promising negative emissions technologies urgently needed to limit global warming to at least below 2 °C, a goal recently reaffirmed at the UN Global Climate Change conference (i.e., COP26). EW relies on the accelerated dissolution of crushed silicate rocks applied to soils and is considered a sustainable solution requiring limited technology. While EW has a high theoretical potential of sequestering CO2, research is still needed to provide accurate estimates of carbon (C) sequestration when applying different silicate materials across distinct climates and major soil types in combination with a variety of plants. Here we elaborate on fundamental advances that must be addressed before EW can be extensively adopted. These include identifying the most suitable environmental conditions, improving estimates of field dissolution rates and efficacy of CO2 removal, and identifying alternative sources of silicate materials to meet future EW demands. We conclude with considerations on the necessity of integrated modeling-experimental approaches to better coordinate future field experiments and measurements of CO2 removal, as well as on the importance of seamlessly coordinating EW with cropland and forest management.
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Affiliation(s)
- Salvatore Calabrese
- Biological and Agricultural Engineering, Texas A&M University, 333 Spence St., College Station, Texas77843, United States
| | - Bastien Wild
- Civil and Environmental Engineering, Princeton University, 59 Olden St., Princeton, New Jersey08540, United States
- Andlinger Center for Energy and the Environment, Princeton University, 59 Olden St., Princeton, New Jersey08540, United States
| | - Matteo B Bertagni
- High Meadows Environmental Institute, Guyot Hall, Princeton University, Princeton, New Jersey08544, United States
| | - Ian C Bourg
- Civil and Environmental Engineering, Princeton University, 59 Olden St., Princeton, New Jersey08540, United States
- High Meadows Environmental Institute, Guyot Hall, Princeton University, Princeton, New Jersey08544, United States
| | - Claire White
- Civil and Environmental Engineering, Princeton University, 59 Olden St., Princeton, New Jersey08540, United States
- Andlinger Center for Energy and the Environment, Princeton University, 59 Olden St., Princeton, New Jersey08540, United States
| | - Felipe Aburto
- Soil and Crop Sciences, Texas A&M University, 370 Olsen Blvd., College Station, Texas77843, United States
| | - Giuseppe Cipolla
- Dipartimento di Ingegneria, University of Palermo, Viale delle Scienze, 90128Palermo, PA, Italy
| | - Leonardo V Noto
- Dipartimento di Ingegneria, University of Palermo, Viale delle Scienze, 90128Palermo, PA, Italy
| | - Amilcare Porporato
- Civil and Environmental Engineering, Princeton University, 59 Olden St., Princeton, New Jersey08540, United States
- High Meadows Environmental Institute, Guyot Hall, Princeton University, Princeton, New Jersey08544, United States
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Yao Z, Prabhakar AK, Cadiam Mohan B, Wang CH. An innovative accelerated carbonation process for treatment of incineration bottom ash and biogas upgrading. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 144:203-209. [PMID: 35390552 DOI: 10.1016/j.wasman.2022.03.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/25/2022] [Accepted: 03/31/2022] [Indexed: 06/14/2023]
Abstract
Incineration is the main technology used for the management of municipal solid waste, in parallel to various recycling programs. However, incineration should not be considered as the final step for waste management as the ash still needs to be treated and disposed properly. In this work, an innovative accelerated carbonation of incineration bottom ash (IBA) using simulated biogas composition from anaerobic digestion processes (a mixture of CH4 and CO2) has been applied to lower the leaching of heavy metals from the carbonated IBA and its associated toxicity. Various temperatures and reaction times were explored for carbonation optimization and it was found that the carbonation at 25 °C for 8 h was the optimal reaction condition by taking into account the degree of carbonation and time constraint. The mineral content, functional groups, thermal stability, leaching patterns and ecotoxicity of both raw IBA and carbonated IBA were tested. It was found that carbonated IBA leached out less heavy metals than the raw IBA due to the locking of heavy metals in the calcite matrix. Cost-benefit analysis was also conducted on the industrial-scale process with a capacity of processing 10 tons of IBA per day. The results indicated that the proposed process had great economic potential.
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Affiliation(s)
- Zhiyi Yao
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore
| | - Arun Kumar Prabhakar
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore
| | - Babu Cadiam Mohan
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore
| | - Chi-Hwa Wang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
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8
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Zhang P, Chen Z, Brown KG, Garrabrants AC, Delapp R, Meeussen JCL, van der Sloot HA, Kosson DS. Impact of carbonation on leaching of constituents from a cementitious waste form for treatment of low activity waste at the DOE Hanford site. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 144:431-444. [PMID: 35461054 DOI: 10.1016/j.wasman.2022.04.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 02/04/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
Carbonation can be a major aging process during disposal of alkaline cementitious waste forms and can impact constituent leaching by changes in material alkalinity, pore structure, and controlling mineral phases. The effect of carbonation on the leaching of major and trace constituents from Cast Stone, a cementitious waste form developed to treat high salt content low activity waste, was studied through a combination of leaching experiments and reactive transport simulations. Diffusive transport of constituents in the waste form was evaluated using reactive transport modeling of diffusion-controlled leaching test results and a geochemical speciation model derived from pH-dependent leaching. Comparisons between Cast Stone materials aged under nitrogen, air, and 2% carbon dioxide in nitrogen showed that carbonation impacts solubility, physical retention and observed diffusivity of major and trace constituents. Carbonation under 2% CO2 decreased the diffusion-controlled leaching of chromium by two orders of magnitude. Modeling results suggest that carbonation may also decrease solubility of technetium while changes to microstructure by carbonation increases effective diffusivity of constituents in Cast Stone.
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Affiliation(s)
- Peng Zhang
- Civil and Environmental Engineering, Vanderbilt University, Station B-351831, Nashville, TN 37235, USA
| | - Zhiliang Chen
- Civil and Environmental Engineering, Vanderbilt University, Station B-351831, Nashville, TN 37235, USA
| | - Kevin G Brown
- Civil and Environmental Engineering, Vanderbilt University, Station B-351831, Nashville, TN 37235, USA
| | - Andrew C Garrabrants
- Civil and Environmental Engineering, Vanderbilt University, Station B-351831, Nashville, TN 37235, USA
| | - Rossane Delapp
- Civil and Environmental Engineering, Vanderbilt University, Station B-351831, Nashville, TN 37235, USA
| | | | - Hans A van der Sloot
- Hans van der Sloot Consultancy, Glenn Millerhof 29, 1628 TS Hoorn, the Netherlands
| | - David S Kosson
- Civil and Environmental Engineering, Vanderbilt University, Station B-351831, Nashville, TN 37235, USA.
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9
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Wang X, Garrabrants AC, Chen Z, van der Sloot HA, Brown KG, Qiu Q, Delapp RC, Hensel B, Kosson DS. The influence of redox conditions on aqueous-solid partitioning of arsenic and selenium in a closed coal ash impoundment. JOURNAL OF HAZARDOUS MATERIALS 2022; 428:128255. [PMID: 35042166 DOI: 10.1016/j.jhazmat.2022.128255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/17/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
A closed coal ash impoundment case study characterized the effects of field redox conditions on arsenic and selenium partitioning through monitoring of porewater and subsurface gas in conjunction with geochemical speciation modeling. When disposed coal ash materials and porewater were recovered for testing, oxidation led to lower arsenic and higher selenium concentrations in leaching test extracts compared to porewater measurements. Multiple lines of evidence suggest multiple mechanisms of arsenic retention are plausible and the concurrent presence of several redox processes and conditions (e.g., methanogenesis, sulfate reduction, and Fe(III)-reduction) controlled by spatial gradients and dis-equilibrium. Geochemical speciation modeling indicated that, under reducing field conditions, selenium was immobilized through the formation of insoluble precipitates Se(0) or FeSe while arsenic partitioning was affected by a progression of reactions including changes in arsenic speciation, reduction in adsorption due to dissolution and recrystallization of hydrous ferric oxides, and precipitation of arsenic sulfide minerals.
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Affiliation(s)
- Xinyue Wang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States
| | - Andrew C Garrabrants
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States
| | - Zhiliang Chen
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States
| | - Hans A van der Sloot
- Hans van der Sloot Consultancy, Glenn Millerhof 29, 1628 TS Hoorn, The Netherlands
| | - Kevin G Brown
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States
| | - Qili Qiu
- School of Environmental Engineering, Nanjing Institute of Technology, Nanjing 211167, China
| | - Rossane C Delapp
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States
| | - Bruce Hensel
- Electric Power Research Institute (EPRI), 3420 Hillview Avenue, Palo Alto, CA 94304, United States
| | - David S Kosson
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States.
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Leaching and Geochemical Modelling of an Electric Arc Furnace (EAF) and Ladle Slag Heap. TOXICS 2022; 10:toxics10010010. [PMID: 35051052 PMCID: PMC8778747 DOI: 10.3390/toxics10010010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/18/2021] [Accepted: 12/27/2021] [Indexed: 11/30/2022]
Abstract
Old metallurgical dumps across Europe represent a loss of valuable land and a potential threat to the environment, especially to groundwater (GW). The Javornik electric arc furnace (EAF) and ladle slag heap, situated in Slovenia, was investigated in this study. The environmental impact of the slag heap was evaluated by combining leaching characterization tests of landfill samples and geochemical modelling. It was shown that throughout the landfill the same minerals and sorptive phases control the leaching of elements of potential concern, despite variations in chemical composition. Although carbonation of the disposed steel slags occurred (molar ratio CO3/(Ca+Mg) = 0.53) relative to fresh slag, it had a limited effect on the leaching behaviour of elements of potential concern. The leaching from the slag heaps had also a limited effect on the quality of the GW. A site-specific case, however, was that leachates from the slag heap were strongly diluted, since a rapid flow of GW fed from the nearby Sava River was observed in the landfill area. The sampling and testing approach applied provides a basis for assessing the long-term impact of release and is a good starting point for evaluating future management options, including beneficial uses for this type of slag.
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Slurry-Phase Carbonation Reaction Characteristics of AOD Stainless Steel Slag. Processes (Basel) 2021. [DOI: 10.3390/pr9122266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Argon oxygen decarburization stainless steel slag (AOD slag) has high mineral carbonation activity. AOD slag carbonation has both the resource utilization of metallurgical waste slag and the carbon reduction effect of CO2 storage. This paper aimed to study carbonation reaction characteristics of AOD slag. Under the slurry-phase accelerated carbonation route, the effect of stirring speed (r) and reaction temperature (T) on AOD slag’s carbonation was studied by controlling the reaction conditions. Mineral composition analysis and microscopic morphology analysis were used to explore the mineral phase evolution of AOD slag during the carbonation process. Based on the unreacted core model, the kinetic model of the carbonation reaction of AOD slag was analyzed. The results showed that the carbonation ratio of AOD slag reached its maximum value of 66.7% under the reaction conditions of a liquid to solid ratio (L/S) of 8:1, a CO2 partial pressure of 0.2 MPa, a stirring speed of 450 r·min−1, and a reaction temperature of 80 °C. The carbonation reaction of AOD slag was controlled by internal diffusion, and the calculated apparent activation energy was 22.28 kJ/mol.
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Chen Z, Cang Z, Yang F, Zhang J, Zhang L. Carbonation of steelmaking slag presents an opportunity for carbon neutral: A review. J CO2 UTIL 2021. [DOI: 10.1016/j.jcou.2021.101738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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O'Connor J, Nguyen TBT, Honeyands T, Monaghan B, O'Dea D, Rinklebe J, Vinu A, Hoang SA, Singh G, Kirkham MB, Bolan N. Production, characterisation, utilisation, and beneficial soil application of steel slag: A review. JOURNAL OF HAZARDOUS MATERIALS 2021; 419:126478. [PMID: 34323725 DOI: 10.1016/j.jhazmat.2021.126478] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/30/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Slags are a co-product produced by the steel manufacturing industry and have mainly been utilised for aggregates in concreting and road construction. The increased utilisation of slag can increase economic growth and sustainability for future generations by creating a closed-loop system, circular economy within the metallurgical industries. Slags can be used as a soil amendment, and slag characteristics may reduce leachate potential of heavy metals, reduce greenhouse gas emissions, as well as contain essential nutrients required for agricultural use and environmental remediation. This review aims to examine various slag generation processes in steel plants, their physicochemical characteristics in relation to beneficial utilisation as a soil amendment, and environmental implications and risk assessment of their utilisation in agricultural soils. In relation to enhancing recycling of these resources, current and emerging techniques to separate iron and phosphorus slag compositions are also outlined in this review. Although there are no known immediate direct threats posed by slag on human health, the associated risks include potential heavy metal contamination, leachate contamination, and bioaccumulation of heavy metals in plants, thereby reaching the food chain. Further research in this area is required to assess the long-term effects of slag in agricultural soils on animal and human health.
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Affiliation(s)
- James O'Connor
- College of Engineering, Science and Enviornment, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Newcastle Institute for Energy and Resources (NIER), University of Newcastle, 70 Vale St, Shortland, NSW 2307, Australia
| | - Thi Bang Tuyen Nguyen
- Newcastle Institute for Energy and Resources (NIER), University of Newcastle, 70 Vale St, Shortland, NSW 2307, Australia
| | - Tom Honeyands
- Newcastle Institute for Energy and Resources (NIER), University of Newcastle, 70 Vale St, Shortland, NSW 2307, Australia.
| | - Brian Monaghan
- University of Wollongong, Northfields Ave, Wollongong, NSW 2522, Australia
| | - Damien O'Dea
- BHP, 480 Queen St, Brisbane, QLD 4000, Australia
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; Department of Environment, Energy and Geoinformatics, Sejong University, 98 Gunja-Dong, Guangjin-Gu, Seoul, Republic of Korea
| | - Ajayan Vinu
- Global Innovative Center for Advanced Nanomaterials, College of Engineering, Science and Environment, The University of Newcastle, Callaghan 2308, NSW, Australia
| | - Son A Hoang
- College of Engineering, Science and Enviornment, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
| | - Gurwinder Singh
- Global Innovative Center for Advanced Nanomaterials, College of Engineering, Science and Environment, The University of Newcastle, Callaghan 2308, NSW, Australia
| | - M B Kirkham
- Department of Agronomy, Kansas State University, Manhattan, KS, United States
| | - Nanthi Bolan
- College of Engineering, Science and Enviornment, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; School of Agriculture and Environment, The University of Western Australia, Perth, WA 6001, Australia; The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia
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14
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Hydration Activity and Carbonation Characteristics of Dicalcium Silicate in Steel Slag: A Review. METALS 2021. [DOI: 10.3390/met11101580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dicalcium silicate is one of the main mineral phases of steel slag. Ascribed to the characteristics of hydration and carbonation, the application of slag in cement production and carbon dioxide sequestration has been confirmed as feasible. In the current study, the precipitation process of the dicalcium silicate phase in steel slag was discussed. Meanwhile, the study put emphasis on the influence of different crystal forms of dicalcium silicate on the hydration activity and carbonation characteristics of steel slag. It indicates that most of the dicalcium silicate phase in steel slag is the γ phase with the weakest hydration activity. The hydration activity of γ-C2S is improved to a certain extent by means of mechanical, high temperature, and chemical activation. However, the carbonation activity of γ-C2S is about two times higher than that of β-C2S. Direct and indirect carbonation can effectively capture carbon dioxide. This paper also summarizes the research status of the application of steel slag in cement production and carbon dioxide sequestration. Further development of the potential of dicalcium silicate hydration activity and simplifying the carbonation process are important focuses for the future.
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15
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Chen Z, Zhang P, Brown KG, Branch JL, van der Sloot HA, Meeussen JCL, Delapp RC, Um W, Kosson DS. Development of a Geochemical Speciation Model for Use in Evaluating Leaching from a Cementitious Radioactive Waste Form. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8642-8653. [PMID: 34132538 DOI: 10.1021/acs.est.0c06227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Cast Stone has been developed to immobilize a fraction of radioactive waste at the Hanford Site; however, constituents of potential concern (COPCs) can be released when in contact with water during disposal. Herein, a representative mineral and parameter set for geochemical speciation modeling was developed for Cast Stone aged in inert and oxic environments, to simulate leaching concentrations of major and trace constituents. The geochemical speciation model was verified using a monolithic diffusion model in conjunction with independent monolithic diffusion test results. Eskolaite (Cr2O3) was confirmed as the dominant mineral retaining Cr in Cast Stone doped with 0.1 or 0.2 wt % Cr. The immobilization of Tc as a primary COPC in Cast Stone was evaluated, and the redox states of porewater within monolithic Cast Stone indicated by Cr are insufficient for the reduction of Tc. However, redox states provided by blast furnace slag (BFS) within the interior of Cast Stone are capable of reducing Tc for immobilization, with the immobilization reaction rate postulated to be controlled by the diffusive migration of soluble Tc in porewater to the surface of reducing BFS particles. Aging in oxic conditions increased the flux of Cr and Tc from monolithic Cast Stone.
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Affiliation(s)
- Zhiliang Chen
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37215, United States
| | - Peng Zhang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37215, United States
| | - Kevin G Brown
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37215, United States
| | - Janelle L Branch
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37215, United States
| | - Hans A van der Sloot
- Hans van der Sloot Consultancy, Glenn Millerhof 29, 1628 TS Hoorn, The Netherlands
| | | | - Rossane C Delapp
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37215, United States
| | - Wooyong Um
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
- Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - David S Kosson
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37215, United States
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16
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Wei C, Dong J, Zhang H, Wang X. Kinetics model adaptability analysis of CO 2 sequestration process utilizing steelmaking slag and cold-rolling wastewater. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124094. [PMID: 33053471 DOI: 10.1016/j.jhazmat.2020.124094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/18/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
Better adaptive kinetics model for CO2 sequestration utilizing wastes in steelmaking plant has a big significance for establishing green out-circulating network system. This work investigated the effect of temperature, L/S ratio and cold-rolling wastewater concentration on carbonation degree in basic oxygen furnace slag and CRW carbonation process, then their kinetics was discussed by surface coverage model and shrinking core model, respectively, in order to evaluate their adaptability and accuracy. Furthermore, CO2 sequestration intensifying factor was originally proposed for considering the carbonation depth, through comparing diffusion coefficient of CO2 between water carbonation and wastewater carbonation. The results showed that carbonation conversion increased as temperature and CRW concentration increased except for L/S ratio, and the maximum carbonation could reach 41.499 ± 1.240%. Because higher prediction error existed in surface coverage model, the shrinking core model had a better adaptability and accuracy for analyzing carbonation process in autoclave. Meanwhile, the CO2 sequestration intensifying factor was 1.6 times as big as carbonation process in distilled water as a result of DCO2 value. CO2 sequestration reaction in our work was controlled by calcium diffused because of DCO2 (0.700-0.976 × 10-4 cm2 s-1) and DCa (0.935-1.149 × 10-5 cm2 s-1). The results above will be helpful for us to better comprehend the reaction kinetics at micro-scale, when the idea of triple wastes self-circulation system network will be established to industrial application.
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Affiliation(s)
- Chao Wei
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Jianping Dong
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Huining Zhang
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China.
| | - Xu Wang
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
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17
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Vallejo Castaño S, Callagon La Plante E, Shimoda S, Wang B, Neithalath N, Sant G, Pilon L. Calcination-free production of calcium hydroxide at sub-boiling temperatures. RSC Adv 2021; 11:1762-1772. [PMID: 35424115 PMCID: PMC8693611 DOI: 10.1039/d0ra08449b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 12/10/2020] [Indexed: 11/21/2022] Open
Abstract
Calcium hydroxide (Ca(OH)2), a commodity chemical, finds use in diverse industries ranging from food, to environmental remediation and construction. However, the current thermal process of Ca(OH)2 production via limestone calcination is energy- and CO2-intensive. Herein, we demonstrate a novel aqueous-phase calcination-free process to precipitate Ca(OH)2 from saturated solutions at sub-boiling temperatures in three steps. First, calcium was extracted from an archetypal alkaline industrial waste, a steel slag, to produce an alkaline leachate. Second, the leachate was concentrated using reverse osmosis (RO) processing. This elevated the Ca-abundance in the leachate to a level approaching Ca(OH)2 saturation at ambient temperature. Thereafter, Ca(OH)2 was precipitated from the concentrated leachate by forcing a temperature excursion in excess of 65 °C while exploiting the retrograde solubility of Ca(OH)2. This nature of temperature swing can be forced using low-grade waste heat (≤100 °C) as is often available at power generation, and industrial facilities, or using solar thermal heat. Based on a detailed accounting of the mass and energy balances, this new process offers at least ≈65% lower CO2 emissions than incumbent methods of Ca(OH)2, and potentially, cement production. A calcination-free route to produce calcium hydroxide from alkaline industrial wastes including leaching, concentration, and temperature-swing precipitation.![]()
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Affiliation(s)
- Sara Vallejo Castaño
- Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California Los Angeles CA 90095 USA +1 310 206 3084.,Department of Mechanical and Aerospace Engineering, University of California Los Angeles CA 90095 USA +1 310 206 5598
| | - Erika Callagon La Plante
- Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California Los Angeles CA 90095 USA +1 310 206 3084.,Institute for Carbon Management, University of California Los Angeles CA 90095 USA.,Department of Materials Science and Engineering, University of Texas Arlington TX 76019 USA
| | - Sho Shimoda
- Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California Los Angeles CA 90095 USA +1 310 206 3084
| | - Bu Wang
- Department of Civil and Environmental Engineering, University of Wisconsin Madison WI 53706 USA
| | - Narayanan Neithalath
- School of Sustainable Engineering and the Built Environment, Arizona State University Tempe AZ 85287 USA
| | - Gaurav Sant
- Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California Los Angeles CA 90095 USA +1 310 206 3084.,Institute for Carbon Management, University of California Los Angeles CA 90095 USA.,Department of Materials Science and Engineering, University of California Los Angeles CA 90095 USA.,California Nanosystems Institute, University of California Los Angeles CA 90095 USA
| | - Laurent Pilon
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles CA 90095 USA +1 310 206 5598.,Institute for Carbon Management, University of California Los Angeles CA 90095 USA
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18
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Zhao Q, Chu X, Mei X, Meng Q, Li J, Liu C, Saxén H, Zevenhoven R. Co-treatment of Waste From Steelmaking Processes: Steel Slag-Based Carbon Capture and Storage by Mineralization. Front Chem 2020; 8:571504. [PMID: 33195057 PMCID: PMC7596899 DOI: 10.3389/fchem.2020.571504] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/17/2020] [Indexed: 11/25/2022] Open
Abstract
The iron and steel industry is an energy-intensive sector, and large amounts of waste/ by-products are generated during the steelmaking process, such as CO2, metallurgical slag, and wastewater. Enhancing the development and deployment of treating waste from the steelmaking process will be environment friendly and resource-saving. Capturing CO2 by steel slag (SS) via mineralization is regarded to be an excellent choice due to the high basicity of the slag. In this paper, recent research on the steel slag-based carbon capture and storage (SS-CCS) by mineralization was summarized. Three routes of SS-CCS are compared including, direct gas-solid carbonation, direct aqueous carbonation, and indirect carbonation, respectively. Furthermore, the challenges and prospects for further development of the SS-CCS were discussed.
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Affiliation(s)
- Qing Zhao
- Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, China.,School of Metallurgy, Northeastern University, Shenyang, China
| | - Xinyi Chu
- School of Metallurgy, Northeastern University, Shenyang, China
| | - Xiaohui Mei
- Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, China.,School of Metallurgy, Northeastern University, Shenyang, China
| | - Qingzhang Meng
- School of Metallurgy, Northeastern University, Shenyang, China
| | - Jingyu Li
- School of Metallurgy, Northeastern University, Shenyang, China
| | - Chengjun Liu
- Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, China.,School of Metallurgy, Northeastern University, Shenyang, China
| | - Henrik Saxén
- Process and Systems Engineering Laboratory, Åbo Akademi University, Åbo/Turku, Finland
| | - Ron Zevenhoven
- Process and Systems Engineering Laboratory, Åbo Akademi University, Åbo/Turku, Finland
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19
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Ragipani R, Bhattacharya S, Akkihebbal SK. Understanding dissolution characteristics of steel slag for resource recovery. WASTE MANAGEMENT (NEW YORK, N.Y.) 2020; 117:179-187. [PMID: 32861080 DOI: 10.1016/j.wasman.2020.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/26/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
Steel slags are generally alkaline with a high calcium content and are viewed as a potential feedstock for carbon dioxide sequestration and utilization, mostly through aqueous mineral carbonation routes. For recovery of multiple metals such as Ca, Fe, Mg, and Si, and generation of value-added products by dissolution and precipitation reactions in aqueous media, enhancing the metal selectivity and extraction efficiency are important. However, there is limited understanding of independent parameters that influence these important characteristics. In this work, a systematic attempt was made to correlate these key dissolution characteristics of basic oxygen furnace slag in acidic media with its mineralogical and physical characteristics, the changes in aqueous chemistry, and the role of potential secondary precipitates. The findings from this study substantiate that steel slag is a potential feedstock because of the calcium being mainly present as orthosilicates, which were found to leach congruently without forming a leached layer that might hinder calcium extraction. The leaching of Fe(II) from the slag is the main source of impurity and its slow oxidation-precipitation leads to a pH plateau at the end of the dissolution step. Oxidation-precipitation of Fe(II) is controlled by hydroxyl concentration in the aqueous solution, which necessitates a pH-swing step by addition of a base after dissolution. Use of surface complexing agents, such as sodium molybdate, can significantly reduce iron impurity in the leachate and obtain an iron-rich slag residue for recycle to iron and steel industry.
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Affiliation(s)
- Raghavendra Ragipani
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai, India; Department of Chemical Engineering, Monash University, Clayton, VIC, Australia; Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Sankar Bhattacharya
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
| | - Suresh K Akkihebbal
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India.
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20
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Zhang H, Zuo Q, Wei C, Lin X, Dong J, Liao C, Xu A. Closed-circulating CO 2 sequestration process evaluation utilizing wastes in steelmaking plant. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 738:139747. [PMID: 32531592 DOI: 10.1016/j.scitotenv.2020.139747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/25/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
The wastes network system exploration in metallurgical process imposes of great significance for advancing green circular economy in steel plant. This paper originally proposes a closed-circulating CO2 sequestering process for wastes appreciation and harmless disposal, and the effect of two circulation strategy, i.e. Slag circulation strategy and cold-rolling waste water(CRW) circulation strategy, on the CO2 uptake efficiency, carbonation degree and desalination rate were systemically discussed. Then, their kinetics are analyzed by model and molecular simulation in detail, respectively. In addition, the energy consumption and the cost are simulated for comprehensively evaluating its superiority. The experimental and molecular simulation results all show that the peak values for both strategies could be achieved when circulation times is in the range of three to five. CRW circulation strategy has a better CO2 uptake efficiency than slag circulation strategy, the CO2 uptake efficiency is about 487kgCO2/tslag and corresponding desalination rate is 48.9%, when CRW is circulated for five times at 60 °C and 20 L/g for 90 min. Adopting CRW circulation strategy, the CO2 sequestration efficiency is averagely doubled comparing to previous results. 129%-183% energy consumption and 35.6% cost would be reduced, which represents that the proposed routine is economical to step forward to industrial application.
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Affiliation(s)
- Huining Zhang
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China.
| | - Quanqin Zuo
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Chao Wei
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Xin Lin
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Jianping Dong
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Chunfa Liao
- Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Anjun Xu
- School of Metallurgy and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
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21
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Zhang X, Chang J. Effect of Different Hydration Time on Carbonation Degree and Strength of Steel Slag Specimens Containing Zeolite. MATERIALS 2020; 13:ma13173898. [PMID: 32899283 PMCID: PMC7503824 DOI: 10.3390/ma13173898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 11/24/2022]
Abstract
Steel slag partially substituted by zeolite (SZ) was beneficial for improving the compressive strength and carbonation degree of SZ specimens after a combined curing (hydration and then carbonation) process due to pozzolanic reaction between them. By previous work results, the zeolitic substitution ratios of 5 wt.% and 15 wt.% in steel slag specimens (SZ5 and SZ15) gained the optimum compressive strength and carbonation degree, respectively, after 1 day hydration and then 2 h carbonation. This study investigated the effect of previous hydration time (1, 3, 7, 14, and 196 days) on carbonation degree and strength of SZ specimens after subsequent carbonation curing. Two zeolitic substitution ratios (5 wt.% and 15 wt.%) were selected and pure steel slag specimens were also prepared as controls. Compressive strength results revealed that the optimum hydration curing time was 1 day and the optimum zeolitic substitution ratio was 5 wt.%. The pozzolanic reaction happened in SZ specimens was divided into early and late pozzolanic reaction. In the late hydration, a new mineral, monocarboaluminate (AFmc) was produced in SZ15 specimens, modifying the carbonation degree and strength further. And the mechanism of pozzolanic reaction in early and late hydration in SZ specimens was explained by several microscopic test methods.
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Affiliation(s)
| | - Jun Chang
- Correspondence: ; Tel.: +86-151-6408-2089
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22
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Steel Slag Characterisation—Benefit of Coupling Chemical, Mineralogical and Magnetic Techniques. MINERALS 2020. [DOI: 10.3390/min10080705] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Steel-making slag is largely used today in road construction and other applications, but significant volumes are landfilled and cannot be recycled for excessive contents in hazardous metals, such as chromium or vanadium. The long-term behaviour of this material is still little known, and the characterisation of large volume slag dumps remains an environmental challenge. In this study various analytical techniques are used to characterise Electric Arc Furnace (EAF) slag landfilled for several decades and exposed to chemical weathering and erosion. Coupling chemical, mineralogical and magnetic techniques helps to understand the relations between hazardous metals and mineral phases. A special interest is given to Fe-bearing minerals microstructure so as to link the magnetic properties of the material to its mineralogical composition. The studied slag presents high amounts of chromium (between 1 and 3 wt. %) and very high magnetic susceptibility values (near 60 × 10−6 m3/kg), explained by the presence of magnetite and a spinel solid solution. Some correlations are found between magnetic susceptibility and potentially hazardous metals, providing new perspectives for future environmental investigations.
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23
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Tailoring the FeO/SiO2 Ratio in Electric Arc Furnace Slags to Minimize the Leaching of Vanadium and Chromium. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10072549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Based on recently published research on leaching control mechanisms in electric arc furnace (EAF) slags, it is assumed that a FeO/SiO2 ratio of around one leads to low leached V and Cr concentrations. This ratio influences the mineral phase composition of the slag toward higher amounts of spinel and a lower solubility of calcium silicate phases by suppressing the formation of magnesiowuestite and highly soluble calcium silicate phases. To evaluate this hypothesis, laboratory and scaled up tests in an EAF pilot plant were performed on slag samples characterized by elevated V and Cr leaching and a high FeO/SiO2 ratio. Prior to the melting experiments, the optimum FeO/SiO2 ratio was calculated via FactSageTM. In the melting experiments, the ratio was adjusted by adding quartz sand, which also decreased the basicity (CaO/SiO2) of the slag. As a reference, remelting experiments without quartz sand addition were conducted and additionally, the influence of the cooling rate of the slag was examined. The remelted (without quartz sand) and the remelted modified slags (with quartz sand) were analyzed chemically and mineralogically and the leaching behavior was investigated. The modification of the slags yielded a minimized release of V and Cr, supporting the hypothesis that the FeO/SiO2 ratio influences the mineralogy and the leaching behavior.
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24
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Chen TL, Jiang W, Shen AL, Chen YH, Pan SY, Chiang PC. CO2 Mineralization and Utilization Using Various Calcium-Containing Wastewater and Refining Slag via a High-Gravity Carbonation Process. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.9b05410] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tse-Lun Chen
- Graduate Institute of Environmental Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei City 10673, Taiwan
- Carbon Cycle Research Center, National Taiwan University, No. 71, Fang-Lan Road, Taipei City 10674, Taiwan
| | - Wen Jiang
- Graduate Institute of Environmental Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei City 10673, Taiwan
| | - Ai-Lin Shen
- China Steel Corporation, Kaohsiung, 1 Chung Kang Road, Hsiao Kang, Kaohsiung, 81233, Taiwan
| | - Yi-Hung Chen
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Zhongxiao E. Road, Taipei City, Taiwan 10608, Taiwan
| | - Shu-Yuan Pan
- Department of Bioenvironmental Systems Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan
| | - Pen-Chi Chiang
- Graduate Institute of Environmental Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei City 10673, Taiwan
- Carbon Cycle Research Center, National Taiwan University, No. 71, Fang-Lan Road, Taipei City 10674, Taiwan
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25
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The effects of carbonation and hydration on the mineralogy and microstructure of basic oxygen furnace slag products. J CO2 UTIL 2019. [DOI: 10.1016/j.jcou.2019.06.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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26
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Librandi P, Nielsen P, Costa G, Snellings R, Quaghebeur M, Baciocchi R. Mechanical and environmental properties of carbonated steel slag compacts as a function of mineralogy and CO2 uptake. J CO2 UTIL 2019. [DOI: 10.1016/j.jcou.2019.05.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Pullin H, Bray AW, Burke IT, Muir DD, Sapsford DJ, Mayes WM, Renforth P. Atmospheric Carbon Capture Performance of Legacy Iron and Steel Waste. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:9502-9511. [PMID: 31317734 PMCID: PMC6706800 DOI: 10.1021/acs.est.9b01265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/15/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Legacy iron (Fe) and steel wastes have been identified as a significant source of silicate minerals, which can undergo carbonation reactions and thus sequester carbon dioxide (CO2). In reactor experiments, i.e., at elevated temperatures, pressures, or CO2 concentrations, these wastes have high silicate to carbonate conversion rates. However, what is less understood is whether a more "passive" approach to carbonation can work, i.e., whether a traditional slag emplacement method (heaped and then buried) promotes or hinders CO2 sequestration. In this paper, the results of characterization of material retrieved from a first of its kind drilling program on a historical blast furnace slag heap at Consett, U.K., are reported. The mineralogy of the slag material was near uniform, consisting mainly of melilite group minerals with only minor amounts of carbonate minerals detected. Further analysis established that total carbon levels were on average only 0.4% while average calcium (Ca) levels exceeded 30%. It was calculated that only ∼3% of the CO2 sequestration potential of the >30 Mt slag heap has been utilized. It is suggested that limited water and gas interaction and the mineralogy and particle size of the slag are the main factors that have hindered carbonation reactions in the slag heap.
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Affiliation(s)
- Huw Pullin
- School
of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Andrew W. Bray
- School
of Earth and Environment, University of
Leeds, Leeds LS2 9JT, United Kingdom
| | - Ian T. Burke
- School
of Earth and Environment, University of
Leeds, Leeds LS2 9JT, United Kingdom
| | - Duncan D. Muir
- School
of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Devin J. Sapsford
- School
of Engineering, Cardiff University, Cardiff CF24 3AA, United Kingdom
| | - William M. Mayes
- Department
of Geography, Geology and Environment, University
of Hull, Hull HU6 7RX, United Kingdom
| | - Phil Renforth
- School
of Engineering and Physical Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
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28
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Mahedi M, Cetin B, Dayioglu AY. Leaching behavior of aluminum, copper, iron and zinc from cement activated fly ash and slag stabilized soils. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 95:334-355. [PMID: 31351620 DOI: 10.1016/j.wasman.2019.06.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 05/02/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
The use of industrial by-products such as fly ash and slag have become very prevalent in soil stabilization owing to its suitable physical and mechanical properties, and economical advantages. However, fly ash and slag have been identified as the potential source of toxic substances, and may pose environmental risk by leaching heavy and trace metals into soil, surface and groundwater. Toxicity characteristic leaching procedure (TCLP) tests were conducted to investigate the environmental hazards associated with the leaching of aluminum (Al), copper (Cu), iron (Fe) and zinc (Zn) from fly ashes, slag, type I/II cement and cement activated fly ash and slag stabilized soils. Sulfate (SO4), dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) concentrations were also quantified to evaluate their influence on metal leaching. To understand the effect of pH on the leaching behavior, pH-dependent leach tests were conducted at the pH ranges of 2-14. Results indicated that an increase in fly ash or slag content may not necessarily increase the effluent metal concentrations. Al, Cu, Zn and DOC followed an amphoteric leaching pattern where concentrations increased in both acidic and basic conditions. In contrast, maximum DIC concentrations occurred at neutral or near neutral pH values. Fe and SO4 showed cationic leaching behavior where concentrations decreased with an increase in effluent pH. Additionally, the leaching controlling mechanisms of the metals were identified by implementing geochemical modeling program Visual MINTEQ. The geochemical analyses indicated that the solubility of Al3+ and Fe3+ were controlled by precipitation/dissolution reactions of oxide/hydroxide minerals at all pH values. Leaching of Cu2+ was only solubility controlled at pH higher than 7, whereas Zn2+ leaching was solubility controlled in the pH range of 8-12.
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Affiliation(s)
- Masrur Mahedi
- Department of Civil, Construction and Environmental Engineering, 813 Bissell Road, Town Engineering Building, Iowa State University, Ames, IA 50011, United States.
| | - Bora Cetin
- Department of Civil, Construction and Environmental Engineering, 813 Bissell Road, Town Engineering Building, Iowa State University, Ames, IA 50011, United States.
| | - Asli Y Dayioglu
- Department of Civil Engineering, Ayazaga Campus, Civil Engineering Building, Istanbul Technical University, Istanbul 34469, Turkey.
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Ai H, Clavier KA, Watts BE, Gale SA, Townsend TG. The efficacy of pH-dependent leaching tests to provide a reasonable estimate of post-carbonation leaching. JOURNAL OF HAZARDOUS MATERIALS 2019; 373:204-211. [PMID: 30921571 DOI: 10.1016/j.jhazmat.2019.03.089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
pH is a vital factor related to the heavy metal leaching from wastes. Over time, waste materials may be naturally weathered in the presence of water and carbon dioxide, reducing their pH and altering their mineralogy. Here we evaluate whether conducting a pH-dependent leaching test on wastes expected to carbonate sufficiently reflects the leaching of these wastes upon carbonation. Certain elements, such as Al and Sb, exhibited different leaching trends for carbonated and un-carbonated samples of two different waste materials. XRD results observed different mineral phases as a result of carbonation in incineration bottom ash. The application of pH-dependent leaching tests on fresh waste samples (at neutral pH values) were found to potentially mischaracterize leaching from carbonated waste samples at similar pH values for some elements and waste materials.
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Affiliation(s)
- Haiping Ai
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Kyle A Clavier
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Benjamin E Watts
- Department of Civil and Coastal Engineering, University of Florida, P.O. Box 116580, Gainesville, FL 32611-6450, USA
| | - S Adrian Gale
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA.
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Du B, Li J, Fang W, Liu J. Comparison of long-term stability under natural ageing between cement solidified and chelator-stabilised MSWI fly ash. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 250:68-78. [PMID: 30981937 DOI: 10.1016/j.envpol.2019.03.124] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 06/09/2023]
Abstract
Cement-solidification and chelator-stabilisation of municipal solid waste incineration fly ash (MSWI-FA) are two main treatment techniques to immobilise heavy metals. Differences in the long-term stabilities of those two methods of heavy-metal immobilisation were explored to aid in determining the better MSWI-FA treatment. However, few comparative studies have been conducted on 6-year-old cement-solidified FA (Ce-6-FA) and chelator-stabilised FA (Ch-6-FA). In this study, we compared the physicochemical and heavy metal leaching characteristics of Ce-6-FA and Ch-6-FA. The chemical speciation of heavy metals was modelled using geochemical software to assess long-term stability. The results showed weaker long-term stability in Pb immobilisation under the chelating system. The leaching concentrations of target heavy metals, acetic acid leaching tests, acid neutralising capacity, and pH-dependent leaching results indicated that Ce-6-FA had higher long-term stability than Ch-6-FA. A column experiment indicated that the cumulative release rates of Pb in Ce-6-FA and Ch-6-FA were 2.49% and 4.72%, respectively. The phase-controlled leaching of Pb in Ce-6-FA mainly occurred through Pb2(OH)3Cl and chloropyromorphite (Pb5(PO4)3Cl), whereas that in Ch-6-FA mainly occurred through Pb5(PO4)3Cl. The decomposition of heavy metal chelates in Ch-6-FA and salt generation in this process led to the release of Pb via the inorganic complex.
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Affiliation(s)
- Bing Du
- Key Laboratory for Solid Waste Management and Environment Safety, School of Environment, Tsinghua University, Beijing, PR China
| | - Jiantao Li
- Key Laboratory for Solid Waste Management and Environment Safety, School of Environment, Tsinghua University, Beijing, PR China
| | - Wen Fang
- Key Laboratory for Solid Waste Management and Environment Safety, School of Environment, Tsinghua University, Beijing, PR China
| | - Jianguo Liu
- Key Laboratory for Solid Waste Management and Environment Safety, School of Environment, Tsinghua University, Beijing, PR China.
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Abstract
Carbon capture, utilisation and storage (CCUS) via mineral carbonation is an effective method for long-term storage of carbon dioxide and combating climate change. Implemented at a large-scale, it provides a viable solution to harvesting and storing the modern crisis of GHGs emissions. To date, technological and economic barriers have inhibited broad-scale utilisation of mineral carbonation at industrial scales. This paper outlines the mineral carbonation process; discusses drivers and barriers of mineral carbonation deployment in Australian mining; and, finally, proposes a unique approach to commercially viable CCUS within the Australian mining industry by integrating mine waste management with mine site rehabilitation, and leveraging relationships with local coal-fired power station. This paper discusses using alkaline mine and coal-fired power station waste (fly ash, red mud, and ultramafic mine tailings, i.e., nickel, diamond, PGE (platinum group elements), and legacy asbestos mine tailings) as the feedstock for CCUS to produce environmentally benign materials, which can be used in mine reclamation. Geographical proximity of mining operations, mining waste storage facilities and coal-fired power stations in Australia are identified; and possible synergies between them are discussed. This paper demonstrates that large-scale alkaline waste production and mine site reclamation can become integrated to mechanise CCUS. Furthermore, financial liabilities associated with such waste management and site reclamation could overcome many of the current economic setbacks of retrofitting CCUS in the mining industry. An improved approach to commercially viable climate change mitigation strategies available to the mining industry is reviewed in this paper.
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Hobson AJ, Stewart DI, Bray AW, Mortimer RJG, Mayes WM, Riley AL, Rogerson M, Burke IT. Behaviour and fate of vanadium during the aerobic neutralisation of hyperalkaline slag leachate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 643:1191-1199. [PMID: 30189535 DOI: 10.1016/j.scitotenv.2018.06.272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/15/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Vanadium is a toxic metal present in alkaline leachates produced during the weathering of steel slags. Slag leaching can therefore have deleterious effects on local watercourses due to metal toxicity, the effects of the high pH (9-12.5) and rapid carbonation (leading to smothering of benthic communities). We studied the fate and behaviour of V in slag leachate both through field observations of a heavily affected stream (Howden Burn, Consett UK) and in controlled laboratory experiments where slag leachates were neutralised by CO2 ingassing from air. V was found to be removed from leachates downstream from the Howden Burn source contemporaneously with a fall in pH, Ca, Al and Fe concentrations. In the neutralisation experiments pH reduced from 12 → 8, and limited quantities of V were incorporated into precipitated CaCO3. The presence of kaolinite clay (i.e. SiOH and AlOH surfaces) during neutralisation experiments had no measureable effect on V uptake in the alkaline to circumneutral pH range. XANES analysis showed that V was present in precipitates recovered from experiments as adsorbed or incorporated V(V) indicating its likely presence in leachates as the vanadate oxyanion (HVO42-). Nano-scale particles of 2-line ferrihydrite also formed in the neutralised leachates potentially providing an additional sorption surface for V uptake. Indeed, removal of V from leachates was significantly enhanced by the addition of goethite (i.e. FeOOH surfaces) to experiments. EXAFS analysis of recovered goethite samples showed HVO42- was adsorbed by the formation of strong inner-sphere complexes, facilitating V removal from solution at pH < 10. Results show that carbonate formation leads to V removal from leachates during leachate neutralisation, and the presence of both naturally occurring and neoformed Fe (oxy)hydroxides provide a potent sink for V in slag leachates, preventing the spread of V in the environment.
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Affiliation(s)
- Andrew J Hobson
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | | | - Andrew W Bray
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - Robert J G Mortimer
- School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Brackenhurst Campus, Southwell, Nottinghamshire NG25 0QF, UK
| | - William M Mayes
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Alex L Riley
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Michael Rogerson
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Ian T Burke
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
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Hobson AJ, Stewart DI, Mortimer RJG, Mayes WM, Rogerson M, Burke IT. Leaching behaviour of co-disposed steel making wastes: Effects of aeration on leachate chemistry and vanadium mobilisation. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 81:1-10. [PMID: 30527025 DOI: 10.1016/j.wasman.2018.09.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/24/2018] [Accepted: 09/28/2018] [Indexed: 06/09/2023]
Abstract
Steelmaking wastes stored in landfill, such as slag and spent refractory liners, are often enriched in toxic trace metals (including V). These may become mobile in highly alkaline leachate generated during weathering. Fresh steelmaking waste was characterised using XRD, XRF, and SEM-EDX. Batch leaching tests were performed under aerated, air-excluded and acidified conditions to determine the impact of atmospheric CO2 and acid addition on leachate chemistry. Phases commonly associated with slag including dicalcium silicate, dicalcium aluminoferrite, a wüstite-like solid solution and free lime were identified, as well as a second group of phases including periclase, corundum and graphite which are representative of refractory liners. During air-excluded leaching, dissolution of free lime and dicalcium silicate results in a high pH, high Ca leachate in which the V concentration is low due to the constraint imposed by Ca3(VO4)2 solubility limits. Under aerated conditions, carbonation lowers the leachate pH and provides a sink for aqueous Ca, allowing higher concentrations of V to accumulate. Below pH 10, leachate is dominated by periclase dissolution and secondary phases including monohydrocalcite and dolomite are precipitated. Storage of waste under saturated conditions that exclude atmospheric CO2 would therefore provide the optimal environment to minimise V leaching during weathering.
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Affiliation(s)
- Andrew J Hobson
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | | | - Robert J G Mortimer
- School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Brackenhurst Campus, Southwell, Nottinghamshire NG25 0QF, UK
| | - William M Mayes
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Mike Rogerson
- School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK
| | - Ian T Burke
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
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Sun J, Liu W, Hu Y, Yang Y, Xu Y, Xu M. Acidification Optimization and Granulation of a Steel-Slag-Derived Sorbent for CO2
Capture. Chem Eng Technol 2018. [DOI: 10.1002/ceat.201700573] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jian Sun
- Huazhong University of Science and Technology; State Key Laboratory of Coal Combustion; School of Energy and Power Engineering; 1037 Luoyu Road 430074 Wuhan China
- Nanjing Normal University; Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control; School of Energy and Mechanical Engineering; 78 Bancang Street 210042 Nanjing China
| | - Wenqiang Liu
- Huazhong University of Science and Technology; State Key Laboratory of Coal Combustion; School of Energy and Power Engineering; 1037 Luoyu Road 430074 Wuhan China
| | - Yingchao Hu
- Huazhong University of Science and Technology; State Key Laboratory of Coal Combustion; School of Energy and Power Engineering; 1037 Luoyu Road 430074 Wuhan China
| | - Yuandong Yang
- Huazhong University of Science and Technology; State Key Laboratory of Coal Combustion; School of Energy and Power Engineering; 1037 Luoyu Road 430074 Wuhan China
| | - Yongqing Xu
- Huazhong University of Science and Technology; State Key Laboratory of Coal Combustion; School of Energy and Power Engineering; 1037 Luoyu Road 430074 Wuhan China
| | - Minghou Xu
- Huazhong University of Science and Technology; State Key Laboratory of Coal Combustion; School of Energy and Power Engineering; 1037 Luoyu Road 430074 Wuhan China
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35
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Stewart DI, Bray AW, Udoma G, Hobson AJ, Mayes WM, Rogerson M, Burke IT. Hydration of dicalcium silicate and diffusion through neo-formed calcium-silicate-hydrates at weathered surfaces control the long-term leaching behaviour of basic oxygen furnace (BOF) steelmaking slag. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:9861-9872. [PMID: 29372528 PMCID: PMC5891564 DOI: 10.1007/s11356-018-1260-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 01/11/2018] [Indexed: 06/07/2023]
Abstract
Alkalinity generation and toxic trace metal (such as vanadium) leaching from basic oxygen furnace (BOF) steel slag particles must be properly understood and managed by pre-conditioning if beneficial reuse of slag is to be maximised. Water leaching under aerated conditions was investigated using fresh BOF slag at three different particle sizes (0.5-1.0, 2-5 and 10 × 10 × 20 mm blocks) and a 6-month pre-weathered block. There were several distinct leaching stages observed over time associated with different phases controlling the solution chemistry: (1) free-lime (CaO) dissolution (days 0-2); (2) dicalcium silicate (Ca2SiO4) dissolution (days 2-14) and (3) Ca-Si-H and CaCO3 formation and subsequent dissolution (days 14-73). Experiments with the smallest size fraction resulted in the highest Ca, Si and V concentrations, highlighting the role of surface area in controlling initial leaching. After ~2 weeks, the solution Ca/Si ratio (0.7-0.9) evolved to equal those found within a Ca-Si-H phase that replaced dicalcium silicate and free-lime phases in a 30- to 150-μm altered surface region. V release was a two-stage process; initially, V was released by dicalcium silicate dissolution, but V also isomorphically substituted for Si into the neo-formed Ca-Si-H in the alteration zone. Therefore, on longer timescales, the release of V to solution was primarily controlled by considerably slower Ca-Si-H dissolution rates, which decreased the rate of V release by an order of magnitude. Overall, the results indicate that the BOF slag leaching mechanism evolves from a situation initially dominated by rapid hydration and dissolution of primary dicalcium silicate/free-lime phases, to a slow diffusion limited process controlled by the solubility of secondary Ca-Si-H and CaCO3 phases that replace and cover more reactive primary slag phases at particle surfaces.
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Affiliation(s)
- Douglas I Stewart
- School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK.
| | - Andrew W Bray
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
| | - Gideon Udoma
- School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - Andrew J Hobson
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
| | - William M Mayes
- School of Environmental Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, UK
| | - Mike Rogerson
- School of Environmental Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, UK
| | - Ian T Burke
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
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Zuo M, Renman G, Gustafsson JP, Klysubun W. Dual slag filters for enhanced phosphorus removal from domestic waste water: performance and mechanisms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:7391-7400. [PMID: 29280098 PMCID: PMC5847628 DOI: 10.1007/s11356-017-0925-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 12/03/2017] [Indexed: 06/07/2023]
Abstract
The phosphorus (P) removal of five combinations of dual filters consisting of blast furnace slag (BFS), argon oxygen decarburisation slag (AOD) and electric arc furnace slag (EAF) was evaluated in column experiments with domestic waste water. The columns were fed with waste water for 24 days. The column with only EAF had the best P removal performance (above 93% throughout the experiment). The speciation of the bound P was evaluated by P K-edge X-ray absorption near-edge structure (XANES) spectroscopy. In all five columns, the main P species of the slag packed in the outlet chamber was amorphous calcium phosphate (ACP). In samples from the inlet chambers, the contributions from crystalline Ca phosphates, P adsorbed on gibbsite and P adsorbed on ferrihydrite were usually much greater, suggesting a shift of P removal mechanism as the waste water travelled from the inlet to the outlet. The results provide strong evidence that P was predominantly removed by the slags through the formation of ACP. However, as the pH decreased with time due to the progressively lower dissolution of alkaline silicate minerals from the slag, the ACP was rendered unstable and hence redissolved, changing the P speciation. It is suggested that this process strongly affected the lifespan of the slag filters. Of the slags examined, EAF slag had the best P removal characteristics and BFS the worst, which probably reflected different dissolution rates of alkaline silicates in the slags.
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Affiliation(s)
- Minyu Zuo
- Division of Land and Water Resources Engineering, KTH (Royal Institute of Technology), Teknikringen 76, 100 44 Stockholm, Sweden
| | - Gunno Renman
- Division of Land and Water Resources Engineering, KTH (Royal Institute of Technology), Teknikringen 76, 100 44 Stockholm, Sweden
| | - Jon Petter Gustafsson
- Division of Land and Water Resources Engineering, KTH (Royal Institute of Technology), Teknikringen 76, 100 44 Stockholm, Sweden
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, 750 07 Uppsala, Sweden
| | - Wantana Klysubun
- Synchrotron Light Research Institute, 111 University Avenue, Muang District,, Nakorn Ratchasima, 30000 Thailand
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Di Gianfilippo M, Verginelli I, Costa G, Spagnuolo R, Gavasci R, Lombardi F. A risk-based approach for assessing the recycling potential of an alkaline waste material as road sub-base filler material. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 71:440-453. [PMID: 29037879 DOI: 10.1016/j.wasman.2017.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 09/12/2017] [Accepted: 10/05/2017] [Indexed: 06/07/2023]
Abstract
In this work we present an integrated risk-based approach that can be used to evaluate the recycling potential of an alkaline waste material such as incineration bottom ash (BA) as unbound material for road sub-base construction. This approach, which is aimed at assessing potential risks to the groundwater resource (in terms of drinking water quality) and human health associated to the leaching of contaminants from the BA, couples the results of leaching tests for the estimation of source concentrations with the fate and transport models usually adopted in risk assessment procedures. The effects of weathering and of the type of leaching test employed to evaluate eluate concentrations were assessed by carrying out different simulations using the results of laboratory leaching tests. Specifically, pH-dependence and column percolation leaching tests were performed on freshly collected and 1-year naturally weathered BA samples produced from a grate-fired incineration plant treating Refuse Derived Fuel (RDF). To evaluate a broad span of possible scenario conditions, a Monte Carlo analysis was performed running 5000 simulations, randomly varying the input parameters within the ranges expected in the field. In nearly all the simulated conditions, the concentrations of contaminants in the groundwater for the specific type of BA tested in this work were well below EU and WHO drinking water quality criteria. Nevertheless, some caution should be paid in the case of the establishment of acidic conditions in the field since in this case the concentration of some elements (i.e. Al, Pb and Zn) is expected to exceed threshold values. In terms of risks to human health, for the considered utilization scenario the probability of exceeding the acceptable reference dose for water ingestion was usually less than 1% (except for Cr and Pb for which the probability was lower than 3.5% and 7%, respectively).
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Affiliation(s)
- Martina Di Gianfilippo
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy
| | - Iason Verginelli
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy.
| | - Giulia Costa
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy.
| | - Riccardo Spagnuolo
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy
| | - Renato Gavasci
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy
| | - Francesco Lombardi
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy
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39
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Kaliyavaradhan SK, Ling TC. Potential of CO 2 sequestration through construction and demolition (C&D) waste—An overview. J CO2 UTIL 2017. [DOI: 10.1016/j.jcou.2017.05.014] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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40
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Comparative Life-cycle Assessment of Slurry and Wet Accelerated Carbonation of BOF Slag. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.egypro.2017.03.1675] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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41
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Yadav S, Mehra A. Experimental study of dissolution of minerals and CO 2 sequestration in steel slag. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 64:348-357. [PMID: 28365273 DOI: 10.1016/j.wasman.2017.03.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 02/13/2017] [Accepted: 03/20/2017] [Indexed: 06/07/2023]
Abstract
This study strives to achieve a substantial amount of steel slag carbonation without using any harmful chemicals. For this purpose, experiments were performed in an aqueous medium, in a semi-batch reactor, to investigate the effect of varying reaction conditions during the steel slag CO2 sequestration process. Further, studying the effect of dissolution on carbonation reactions and the mineralogical changes that subsequently occur within the slag helps provide insight into the parameters that ultimately have an impact on the carbonation rate as well the magnitude of the impact.
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Affiliation(s)
- Shashikant Yadav
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
| | - Anurag Mehra
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
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42
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Du J, Bu Y, Guo S, Tian L, Shen Z. Effects of epoxy resin on ground-granulated blast furnace slag stabilized marine sediments. RSC Adv 2017. [DOI: 10.1039/c7ra06460h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this study, an environmentally friendly epoxy resin is mixed with ground-granulated blast furnace slag (GGBS) for use as a stabilizer to enhance mechanical performance and leaching resistance properties of marine sediments.
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Affiliation(s)
- Jiapei Du
- College of Petroleum Engineering
- China University of Petroleum
- 266580 Qingdao
- China
| | - Yuhuan Bu
- College of Petroleum Engineering
- China University of Petroleum
- 266580 Qingdao
- China
| | - Shenglai Guo
- College of Petroleum Engineering
- China University of Petroleum
- 266580 Qingdao
- China
| | - Leiju Tian
- College of Petroleum Engineering
- China University of Petroleum
- 266580 Qingdao
- China
| | - Zhonghou Shen
- College of Petroleum Engineering
- China University of Petroleum
- 266580 Qingdao
- China
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43
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Li J, Liu B, Zeng Y, Wang Z. Mineralogical determination and geo-chemical modeling of chromium release from AOD slag: Distribution and leachability aspects. CHEMOSPHERE 2017; 167:360-366. [PMID: 27743532 DOI: 10.1016/j.chemosphere.2016.10.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 09/28/2016] [Accepted: 10/07/2016] [Indexed: 06/06/2023]
Abstract
AOD (argon oxygen decarburization) slag, which is the by-product of the stainless steel refining process, is a recyclable slag because of its high content of calcium and silicon. The leaching toxicity cannot be ignored in the recycling process because the slag contains a certain amount of Cr. In this study, the mineral analysis, batch leaching tests and thermodynamic and kinetic modeling by PHREEQC combined with FactSage software were performed to explore the influence of the dissolution of primary minerals and the precipitation of secondary minerals on the elution of Cr from AOD slag. The results indicated that the main minerals in the original AOD slag are larnite, merwinite, pyroxene and periclase. Cr was dispersed in the mineral phases mentioned above. The simulation of Cr leaching controlled by Cr(III)-hydroxide corresponded better to the batch leaching tests, while the Cr leaching controlled by chromite or double control was underestimated. Increasing the L/S ratio enhances the pH of the leachate and restrains the elution of Cr from the AOD slag.
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Affiliation(s)
- Junguo Li
- College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, PR China.
| | - Bao Liu
- College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, PR China
| | - Yanan Zeng
- College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, PR China
| | - Ziming Wang
- College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063009, PR China
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Loncnar M, van der Sloot HA, Mladenovič A, Zupančič M, Kobal L, Bukovec P. Study of the leaching behaviour of ladle slags by means of leaching tests combined with geochemical modelling and mineralogical investigations. JOURNAL OF HAZARDOUS MATERIALS 2016; 317:147-157. [PMID: 27262282 DOI: 10.1016/j.jhazmat.2016.05.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 05/11/2016] [Accepted: 05/14/2016] [Indexed: 06/05/2023]
Abstract
In this study, the leachability of freshly produced ladle slag derived from both austenitic and ferritic stainless steel production, and from electrical and structural steel production, was investigated, in order to determine whether variations in the chemical and mineralogical composition of these slags affect their leaching behaviour. The effect of the method used for slag cooling was also studied. The results obtained by using the single batch test were combined with those obtained by means of more sophisticated characterisation leaching tests, which, in combination with geochemical speciation modelling, helped to better identify the release mechanisms and phases that control the release of individual elements. It was found that, although variations in the chemical composition of the slag can affect the slag's minerology, neither such variations, nor the choice of the slag cooling treatment, have a significant effect on the leachability of individual elements, since the leaching is governed by surface phenomena. In fact, the mineral transformations on the slag surface, rather than the bulk mineral composition, dictate the release of these elements from the ladle slag. The solubility-controlling phases were predicted by multi-element modelling, and verified to the extent made possible by the performed mineralogical investigations.
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Affiliation(s)
- Mojca Loncnar
- Acroni, d. o. o., Cesta Borisa Kidriča 44, SI-4270 Jesenice, Slovenia.
| | - Hans A van der Sloot
- Hans van der Sloot Consultancy, Dorpsstraat 216, 1721 BV Langedijk, The Netherlands, The Netherlands
| | - Ana Mladenovič
- Slovenian National Building and Civil Engineering Institute, Dimičeva cesta 12, SI-1000 Ljubljana, Slovenia
| | - Marija Zupančič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Lara Kobal
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Peter Bukovec
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
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Gopinath S, Mehra A. Carbon sequestration during steel production: Modelling the dynamics of aqueous carbonation of steel slag. Chem Eng Res Des 2016. [DOI: 10.1016/j.cherd.2016.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abbaspour A, Tanyu BF, Cetin B. Impact of aging on leaching characteristics of recycled concrete aggregate. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:20835-20852. [PMID: 27480163 DOI: 10.1007/s11356-016-7217-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 07/08/2016] [Indexed: 06/06/2023]
Abstract
The focus of this study was to evaluate the effects of stockpiling (aging) on leaching of elements in recycled concrete aggregate (RCA) that may contribute to tufaceous constituent formation. Speciation and leaching controlling mechanisms of these elements were identified via geochemical modeling. The effects of stockpiling were simulated by comparing freshly produced RCA with RCA aged as part of this study for 1 year both in the laboratory and in the field. Leachate samples were generated following batch water leach test (WLT) and US Geological Survey leach test (USGSLT) methods. USGSLTs were conducted both on the laboratory and field samples while WLT was only conducted on laboratory samples. During the laboratory aging, it is observed that the carbonate content of RCA, measured as calcite equivalent, increased 20 % (i.e., from ∼100 to 120 mg/g) within a year time frame. The leachate extracted from RCA showed minor changes in pH and more significant decreases in electrical conductivity (i.e., ∼300 to 100 μS/cm). A comparison between laboratory and field samples revealed that the RCA aged much slower in the field than in the laboratory within a year. Comparisons between two leach extraction methods on the laboratory conditions showed that the total leached concentrations (TLCs) of most of the constituents from USGSLT were appreciably lower than the ones measured via WLT method. The results of geochemical modeling analyses showed that Al, Si, Fe, Ca, Mg, and Cu exist in their oxidized forms as Al3+, Fe3+, Si4+, Ca2+, Mg2+, and Cu2+ and results revealed that these elements are primarily controlled by the solubility of gibbsite, hematite, silica gel, calcite, magnesite, and tenorite solid phases, respectively. One of the significant findings of the study was to identify the changes in leaching behavior of Ca, Si, Mg, Al, Fe, and Cu due to carbonation.
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Affiliation(s)
- Aiyoub Abbaspour
- Department of Civil, Environmental and Infrastructure Engineering, George Mason University, Fairfax, VA, 22030, USA
| | - Burak F Tanyu
- Department of Civil, Environmental and Infrastructure Engineering, George Mason University, Fairfax, VA, 22030, USA.
| | - Bora Cetin
- Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA, 50011, USA
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Teir S, Kotiranta T, Pakarinen J, Mattila HP. Case study for production of calcium carbonate from carbon dioxide in flue gases and steelmaking slag. J CO2 UTIL 2016. [DOI: 10.1016/j.jcou.2016.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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48
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49
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Polettini A, Pomi R, Stramazzo A. CO2 sequestration through aqueous accelerated carbonation of BOF slag: A factorial study of parameters effects. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 167:185-195. [PMID: 26686071 DOI: 10.1016/j.jenvman.2015.11.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 06/05/2023]
Abstract
A factorial study was conducted on basic oxygen furnace slag from a steelmaking industry with the aim of systematically identifying the individual and joint effects of the operating parameters (total pressure, CO2 concentration in the gas phase and temperature) on the CO2 sequestration yield of a direct aqueous carbonation process. Each operating parameter was varied over a range of three levels according to a 3(3) factorial design, resulting in 27 carbonation experiments. The carbonation performance and the changes in particle size and mineralogical characteristics of the slag were investigated in detail. The analysis of the experimental results indicated large effects of the operating factors on CO2 uptake, which was observed to span the range 6.7-53.6 g CO2/100 g slag. The best carbonation performance achieved was particularly significant compared to previous studies, even more considering the relative mild operating conditions adopted (P = 5 bar, C = 40% vol. CO2, T = 50 °C, t = 4 h). The analysis of the solid and liquid phases at the end of the carbonation treatment evidenced significant changes in the physical, chemical and mineralogical composition of the material. In particular, evidence was gained of other elements (Mg, Fe, Mn, Zn) in addition to Ca being intensively involved in the carbonation reactions, with a variety of carbonate phases being produced in addition to calcium carbonate forms.
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Affiliation(s)
- Alessandra Polettini
- Department of Civil and Environmental Engineering, University of Rome "La Sapienza", Via Eudossiana 18 - 00184, Rome, Italy.
| | - Raffaella Pomi
- Department of Civil and Environmental Engineering, University of Rome "La Sapienza", Via Eudossiana 18 - 00184, Rome, Italy.
| | - Alessio Stramazzo
- Department of Civil and Environmental Engineering, University of Rome "La Sapienza", Via Eudossiana 18 - 00184, Rome, Italy.
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Costa G, Polettini A, Pomi R, Stramazzo A. Leaching modelling of slurry-phase carbonated steel slag. JOURNAL OF HAZARDOUS MATERIALS 2016; 302:415-425. [PMID: 26489916 DOI: 10.1016/j.jhazmat.2015.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/01/2015] [Accepted: 10/04/2015] [Indexed: 06/05/2023]
Abstract
In the present work the influence of accelerated mineral carbonation on the leaching behaviour of basic oxygen furnace steel slag was investigated. The environmental behaviour of the material as evaluated through the release of major elements and toxic metals under varying pH conditions was the main focus of the study. Geochemical modelling of the eluates was used to derive a theoretical description of the underlying leaching phenomena for the carbonated material as compared to the original slag. Among the investigated elements, Ca and Si were most appreciably affected by carbonation. A very clear effect of carbonation on leaching was observed for silicate phases, and lower-Ca/Si-ratio minerals were found to control leaching in carbonated slag eluates as compared to the corresponding untreated slag sample as a result of Ca depletion from the residual slag particles. Clear evidence was also gained of solubility control for Ca, Mg and Mn by a number of carbonate minerals, indicating a significant involvement of the original slag constituents in the carbonation process. The release of toxic metals (Zn, V, Cr, Mo) was found to be variously affected by carbonation, owing to different mechanisms including pH changes, dissolution/precipitation of carbonates as well as sorption onto reactive mineral surfaces. The leaching test results were used to derive further considerations on the expected metal release levels on the basis of specific assumptions on the relevant pH domains for the untreated and carbonated slag.
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Affiliation(s)
- G Costa
- Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy
| | - A Polettini
- Department of Civil and Environmental Engineering, University of Rome "La Sapienza", Via Eudossiana 18, 00184 Rome, Italy.
| | - R Pomi
- Department of Civil and Environmental Engineering, University of Rome "La Sapienza", Via Eudossiana 18, 00184 Rome, Italy
| | - A Stramazzo
- Department of Civil and Environmental Engineering, University of Rome "La Sapienza", Via Eudossiana 18, 00184 Rome, Italy
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