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Kashimura K, Oshita A, Miyata T, Segawa S, Yokawa H, Tendo K, Kurooka K. Manufacturing carbon storage sintered body using microwave-selective and high-speed heating techniques. Sci Rep 2023; 13:5122. [PMID: 36991136 DOI: 10.1038/s41598-023-32136-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023] Open
Abstract
Microwave sintering of fly ash samples with large amounts of unburned carbon and CaCO3 was examined in this study. To this end, CaCO3 was mixed with fly ash sintered body to fix CO2. The decomposition of CaCO3 was observed when the raw material was heated to 1000 °C using microwave irradiation; however, a sintered body containing aragonite was obtained when the raw material was heated to 1000 °C with added water. Further, carbides in the fly ash could be selectively heated by controlling the microwave irradiation. The microwave magnetic field created a temperature gradient of 100 °C in a narrow region of 2.7 μm or less in the sintered body, and it helped suppress the CaCO3 decomposition in the mixture during sintering. By storing water in the gas phase before spreading, CaCO3, which is difficult to sinter using conventional heating, can be sintered without decomposing.
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Affiliation(s)
- K Kashimura
- Faculty of Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501, Japan.
| | - A Oshita
- Faculty of Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501, Japan
| | - T Miyata
- Faculty of Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501, Japan
| | - S Segawa
- Chugoku Kouatsu Concrete Industries Co., Ltd., 4-33 Komachi, Naka-ku, Hiroshima, 730-0041, Japan
| | - H Yokawa
- Faculty of Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501, Japan
| | - K Tendo
- Chugoku Kouatsu Concrete Industries Co., Ltd., 4-33 Komachi, Naka-ku, Hiroshima, 730-0041, Japan
| | - K Kurooka
- Chugoku Kouatsu Concrete Industries Co., Ltd., 4-33 Komachi, Naka-ku, Hiroshima, 730-0041, Japan
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2
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Liu X, Zou Y, Geng R, Li B, Zhu T. Red mud recycling by Fe and Al recovery through the hydrometallurgy method: a collaborative strategy for aluminum and iron industry. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:43377-43386. [PMID: 36656474 DOI: 10.1007/s11356-023-25389-8] [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: 07/14/2022] [Accepted: 01/14/2023] [Indexed: 06/17/2023]
Abstract
In this work, a collaborative strategy for the aluminum and iron industry based on red mud recycling through the hydrometallurgy method was proposed. In this method, Fe3+ and Al3+ were firstly separated from the red mud by using H2SO4 as a leaching agent, which was by-produced from the sintering process of an iron and steel industry. Multiple influence factors on the leaching process were investigated, with the H2SO4 addition amount showing the strongest influence on the leaching rates of Al and Fe. The main components of the filter residue were CaSO4, TiO2, and SiO2, which could be reused as additives in the building materials. Subsequently, the final Fe recovery product was obtained through the co-precipitation, Fe/Al separation, and Fe(OH)3 calcination. In the final product, the content of Fe2O3 reached 82.87%, and the iron grade was 58.01%, meeting the requirement being raw materials for sinter production.
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Affiliation(s)
- Xiaolong Liu
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Yang Zou
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ran Geng
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China
| | - Bin Li
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China
| | - Tingyu Zhu
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China
- Institute of Urban Environment, Center for Excellence in Regional Atmospheric Environment, Chinese Academy of Sciences, Xiamen, 361021, China
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3
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Bedrnová E, Doušová B, Koloušek D, Maxová K, Angelis M. Adsorption of Phosphate and Ammonium on Waste Building Sludge. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1448. [PMID: 36837078 PMCID: PMC9968144 DOI: 10.3390/ma16041448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Two selected waste building sludges (WBS) were used in this study: (i) sludge from the production and processing of prestressed concrete pillars (B) and (ii) sludge from the production of technical stone (TS). The materials were used in their original and Fe-modified forms (BFe/TSFe) for the adsorption of NH4+ and PO43- from contaminated waters. The experiments were performed on a model solution simulating real wastewater with a concentration of 1.7 mmol·L-1 (NH4+) and 0.2 mmol·L-1 (PO43-). The adsorption of PO43- had a high efficiency (>99%) on B, BFe and TSFe, while for TS, the adsorption of PO43- was futile due to the high content of available P in the raw TS. The adsorption of NH4+ on all sorbents (B/BFe, TS/TSFe) had a lower efficiency (<60%), while TS proved to be the most effective. Leaching tests were performed according to the CSN EN 12457 standard for B/BFe and TS/TSFe before and after NH4+ and PO43- sorption when the contents of these ions in the leachates were affected by adsorption experiments in the cases of B and TS. For BFe and TSFe, the ion content in the leachates before and after the adsorption experiments was similar.
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Sim SR, Ryu DW. Effect of the Concrete Slurry Waste Ratio on Supercritical CO 2 Sequestration. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16020742. [PMID: 36676481 PMCID: PMC9866696 DOI: 10.3390/ma16020742] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/06/2023] [Accepted: 01/07/2023] [Indexed: 06/12/2023]
Abstract
To prevent drastic climate changes due to global warming, it is necessary to transition to a carbon-neutral society by reducing greenhouse gas emissions in all industrial sectors. This study aimed to develop carbon utilization sequestration technology that uses the concrete slurry water generated during the production of concrete as a new CO2 sink to reduce CO2 emissions from the cement industry. This was achieved by performing supercritical CO2 carbonation by varying the concrete slurry waste (CSW) ratio. The study's results confirmed that, according to the CSW ratio (5 to 25%), complete carbonation occurred within only 10 min of the reaction at 40 °C and 100 bar.
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5
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Dousova B, Machovic V, Lhotka M, Reiterman P, Bedrnova E, Kolousek D. Mechanism of chromate adsorption on Fe-modified concrete slurry waste. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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Supercritical CO2 Curing of Resource-Recycling Secondary Cement Products Containing Concrete Sludge Waste as Main Materials. MATERIALS 2022; 15:ma15134581. [PMID: 35806711 PMCID: PMC9267265 DOI: 10.3390/ma15134581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 11/17/2022]
Abstract
This study aims to develop highly durable, mineral carbonation-based, resource-recycling, secondary cement products based on supercritical carbon dioxide (CO2) curing as part of carbon capture utilization technology that permanently fixes captured CO2. To investigate the basic characteristics of secondary cement products containing concrete sludge waste (CSW) as the main materials after supercritical CO2 curing, the compressive strengths of the paste and mortar (fabricated by using CSW as the main binder), ordinary Portland cement, blast furnace slag powder, and fly ash as admixtures were evaluated to derive the optimal mixture for secondary products. The carbonation curing method that can promote the surface densification (intensive CaCO3 formation) of the hardened body within a short period of time using supercritical CO2 curing was defined as “Lean Carbonation”. The optimal curing conditions were derived by evaluating the compressive strength and durability improvement effects of applying Lean Carbonation to secondary product specimens. As a result of the experiment, for specimens subjected to Lean Carbonation, compressive strength increased by up to 12%, and the carbonation penetration resistance also increased by more than 50%. The optimal conditions for Lean Carbonation used to improve compressive strength and durability were found to be 35 °C, 80 bar, and 1 min.
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Abstract
Production of Portland clinker is inherently associated with CO2 emissions originating from limestone decomposition, the irreplaceable large-scale source of calcium oxide needed. Besides carbon capture and storage, CO2 mineralization is the only lever left to reduce these process emissions. CO2 mineralization is a reversal reaction to clinker production—CO2 is bound into stable carbonates in an exothermic process. It can be applied in several environmentally and economically favorable ways at different stages of clinker, cement and concrete life cycle. These possibilities are assessed and discussed in this contribution. The results demonstrate that when combined with concrete recycling, the complete circularity of all its constituents, including the process CO2 emissions from the clinker, can be achieved and the overall related CO2 intensity significantly reduced.
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Effect of Cementitious Materials on the Engineering Properties of Lightweight Aggregate Mortars Containing Recycled Water. MATERIALS 2022; 15:ma15051967. [PMID: 35269197 PMCID: PMC8911749 DOI: 10.3390/ma15051967] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 12/10/2022]
Abstract
With the trend toward taller and larger structures, the demand for high-strength and lightweight cement concrete has increased in the construction industry. Equipment for transporting ready-mixed concrete is frequently used to bring concrete to construction sites, and washing this equipment generates a large amount of recycled water, which is an industrial by-product. In this study, we recycled this water as the pre-wetting water for lightweight aggregate and as mixing water, and we substituted blast furnace slag powder (BS) and fly ash (FA) as cementitious materials (Cm). In addition, we evaluated the fluidity, compressive strength, tensile strength, drying shrinkage, and accelerated carbonation depth of lightweight ternary cementitious mortars (TCMs) containing artificial lightweight aggregate and recycled water. The 28-day compressive strengths of the lightweight TCM specimens with BS and FA were ~47.2–51.7 MPa, except for the specimen with 20% each of BS and FA (40.2 MPa), which was higher than that of the control specimen with 100% OPC (45.9 MPa). Meanwhile, the 28-day tensile strengths of the lightweight TCM specimens containing BS and FA were ~2.81–3.20 MPa, which are ~13.7–29.5% higher than those of the control specimen. In this study, the TCM specimen with 5% each of BS and FA performed the best in terms of the combination of compressive strength, tensile strength, and carbonation resistance.
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9
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Sim SR, Ryu DW. Fundamental Studies on CO 2 Sequestration of Concrete Slurry Water Using Supercritical CO 2. MATERIALS 2021; 15:ma15010094. [PMID: 35009240 PMCID: PMC8746255 DOI: 10.3390/ma15010094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 11/22/2022]
Abstract
To prevent drastic climate change due to global warming, it is necessary to transition to a carbon-neutral society by reducing greenhouse gas emissions in all industrial sectors. This study aims to prepare measures to reduce the greenhouse gas in the cement industry, which is a large source of greenhouse gas emissions. The research uses supercritical CO2 carbonation to develop a carbon utilization fixation technology that uses concrete slurry water generated via concrete production as a new CO2 fixation source. Experiments were conducted using this concrete slurry water and supernatant water under different conditions of temperature (40 and 80 °C), pressure (100 and 150 bar), and reaction time (10 and 30 min). The results showed that reaction for 10 min was sufficient for complete carbonation at a sludge solids content of 5%. However, reaction products of supernatant water could not be identified due to the presence of Ca(HCO3)2 as an aqueous solution, warranting further research.
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10
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Li F, Liu L, Yang Z, Li S. Physical and mechanical properties and micro characteristics of fly ash-based geopolymer paste incorporated with waste Granulated Blast Furnace Slag (GBFS) and functionalized Multi-Walled Carbon Nanotubes (MWCNTs). JOURNAL OF HAZARDOUS MATERIALS 2021; 401:123339. [PMID: 32659576 DOI: 10.1016/j.jhazmat.2020.123339] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/26/2020] [Accepted: 06/27/2020] [Indexed: 06/11/2023]
Abstract
Geopolymers are highly durable and have favorable mechanical properties, and are thus regarded as an eco-friendly alternative to traditional ordinary Portland cement binder. In this study, MWCNTs are obtained through a modification method using a compound of nitric acid and sulfuric acid, and are then dispersed using three types of dispersants. Fly ash-based geopolymers are prepared to validate the effectiveness and feasibility of adopting 0.05 wt.%, 0.10 wt.%, and 0.15 wt.% functionalized MWCNTs and substitution ratios of 10 %-40 % of fly ash with GBFS. The structure and dispersity of the functionalized MWCNTs in aqueous solutions are characterized using FT-IR and TEM, respectively. Then, the setting time, water absorption capacity, and mechanical behaviors are evaluated. In addition, SEM-EDS, FT-IR, TG-DSC, 29Si NMR, and XRD are employed to investigate the morphology, elemental components, mineralogical phases, and geopolymerization degree of the gel products. The experimental results show that the functionalized MWCNTs comprise -COOH and -OH groups and can be uniformly dispersed in aqueous solution containing SDS dispersant. Furthermore, geopolymer paste incorporated with 0.1 wt.% functionalized MWCNTs and having 30 % substitution of fly ash with GBFS exhibits a higher compressive and flexural strength and a lower water absorption capacity compared with all other geopolymer pastes.
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Affiliation(s)
- Faping Li
- School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China
| | - Lisheng Liu
- School of Urban Construction, Wuchang University of Technology, Wuhan, Hubei 430223, China
| | - Zheming Yang
- School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China
| | - Shan Li
- School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China.
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11
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Kaliyavaradhan SK, Ling TC, Mo KH. CO2 sequestration of fresh concrete slurry waste: Optimization of CO2 uptake and feasible use as a potential cement binder. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.101330] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Tang P, Chen W, Xuan D, Cheng H, Poon CS, Tsang DCW. Immobilization of hazardous municipal solid waste incineration fly ash by novel alternative binders derived from cementitious waste. JOURNAL OF HAZARDOUS MATERIALS 2020; 393:122386. [PMID: 32114128 DOI: 10.1016/j.jhazmat.2020.122386] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/28/2020] [Accepted: 02/21/2020] [Indexed: 06/10/2023]
Abstract
This work aims to immobilize hazardous municipal solid waste incineration fly ash (IFA) using alternative binders recycled from cementitious waste (CW) that was dehydrated. The dehydration temperature of CW applied was 200 °C, 500 °C and 800 °C, and the resulted binder was labelled as DCW2, DCW5 and DCW8, respectively. Thermal treatment increased the rehydration capacity of DCWs. Higher temperatures at 500 °C) can increase the amount of dehydrated phases, and contribute to a higher 28-day strength of DCW pastes. The DCW5 paste had the highest 28-day strength which was 18.74 MPa. The dicalcium silicate phase can be formed in DCW8, which resulted in its slow strength development and a lower 28-day strength compared to the DCW5 paste (about 50 % lower). Chloride contained in IFA can take part in the DCW hydration and contribute to the strength development of the binder-IFA pastes. The use of DCWs as binders had better immobilization efficiency of Pb compared to OPC. Furthermore, the CO2 emission for preparing DCW2, DCW5, and DCW8 was 94 %, 86 % and 65 % lower than that of OPC, respectively. The DCWs can be considered as alternative binders regarding the recycling and immobilization of IFA.
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Affiliation(s)
- Pei Tang
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, PR China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
| | - Wei Chen
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, 430070, PR China.
| | - Dongxing Xuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Hiuwun Cheng
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
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Tang P, Xuan D, Cheng HW, Poon CS, Tsang DCW. Use of CO 2 curing to enhance the properties of cold bonded lightweight aggregates (CBLAs) produced with concrete slurry waste (CSW) and fine incineration bottom ash (IBA). JOURNAL OF HAZARDOUS MATERIALS 2020; 381:120951. [PMID: 31416042 DOI: 10.1016/j.jhazmat.2019.120951] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/24/2019] [Accepted: 07/30/2019] [Indexed: 06/10/2023]
Abstract
In this study, concrete slurry waste (CSW) obtained from ready-mixed concrete plants was recycled as a fresh cementitious binder and used together with municipal solid waste incineration (MSWI) fine bottom ash (IBA) from waste-to-energy plants to produce cold bonded lightweight aggregates (CBLAs) by using a pelletizing technique. The influence of different curing methods on the properties of the produced CBLAs were experimentally investigated, including moist curing, steam curing, and accelerated CO2 curing at 0.1 bar and flow-through CO2 curing under ambient pressure. The results showed that CBLAs obtained by steam curing at 60 °C had the highest pellet strength, and the CO2 cured samples had the lowest water absorption values. CO2 curing with a pressure of 0.1 bar promoted a better pellet strength. The CO2 curing method can sequestrate 3.5-4.1% (by mass of pellets) of CO2, which can serve as a sustainable CO2 sequestration process to produce CBLAs.
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Affiliation(s)
- Pei Tang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
| | - Dongxing Xuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Hiu Wun Cheng
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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Tang P, Xuan D, Poon CS, Tsang DCW. Valorization of concrete slurry waste (CSW) and fine incineration bottom ash (IBA) into cold bonded lightweight aggregates (CBLAs): Feasibility and influence of binder types. JOURNAL OF HAZARDOUS MATERIALS 2019; 368:689-697. [PMID: 30738253 DOI: 10.1016/j.jhazmat.2019.01.112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
In this study, concrete slurry waste (CSW) and fine incineration bottom ash (IBA) (<2.36 mm) were innovatively valorized to produce cold bonded lightweight aggregates (CBLAs) through a pelletizing method. The contribution of CSW to CBLAs as a fresh recycled cementitious paste was investigated and the influences of adding various binders (OPC, GGBS, lime, silica fume) on the properties of CBLAs were explored. Meanwhile, the leaching behaviours of the produced CBLAs were further assessed. The experimental results showed that CSW and IBA had a good compatibility to produce CBLAs by the pelletizing method. The use of fresh and workable CSW collected from ready-mixed concrete plants as a recycled cementitious paste could effectively bond the IBA particles. Due to the residual hydration behaviour of CSW, the produced CBLAs, even without additional binders, had good mechanical properties. The use of small percentages of cement and GGBS as additional binders could significantly increase the strength of CBLAs, while the use of lime and silica fume only showed slight improvement due to the high porosity induced. Moreover, it was found that using GGBS which could react with Ca(OH)2 in CSW to lower the pH benefited the immobilization of heavy metals in CBLAs.
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Affiliation(s)
- Pei Tang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Dongxing Xuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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15
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Investigation of the Use of Recycled Concrete Aggregates Originating from a Single Ready-Mix Concrete Plant. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8112149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The waste produced from ready-mixed concrete (RMC) industries poses an environmental challenge regarding recycling. Three different waste products form RMC plants were investigated for use as recycled aggregates in construction applications. Crushed hardened concrete from test specimens of at least 40 MPa compressive strength (HR) and crushed hardened concrete from returned concrete (CR) were tested for their suitability as concrete aggregates and then used as fine and coarse aggregate in new concrete mixtures. In addition, cement sludge fines (CSF) originating from the washing of concrete trucks were tested for their properties as filler for construction applications. Then, CSF was used at 10% and 20% replacement rates as a cement replacement for mortar production and as an additive for soil stabilization. The results show that, although there is some reduction in the properties of the resulting concrete, both HR and CR can be considered good-quality recycled aggregates, especially when the coarse fraction is used. Furthermore, HR performs considerably better than CR both as coarse and as fine aggregate. CSF seems to be a fine material with good properties as a filler, provided that it is properly crushed and sieved through a 75 μm sieve.
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16
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Xu Y, Chen W, Jin R, Shen J, Smallbone K, Yan C, Hu L. Experimental investigation of photocatalytic effects of concrete in air purification adopting entire concrete waste reuse model. JOURNAL OF HAZARDOUS MATERIALS 2018; 353:421-430. [PMID: 29702457 DOI: 10.1016/j.jhazmat.2018.04.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 04/09/2018] [Accepted: 04/14/2018] [Indexed: 06/08/2023]
Abstract
This research investigated the capacities of recycled aggregate concrete adopting entire concrete waste reuse model in degrading NO2. Two major issues within environmental sustainability were addressed: concrete waste reuse rate and mitigation of hazards substances in the polluted air. The study consisted of two stages: identification of proper replacement rates of recycled concrete wastes in new concrete mixture design, and the evaluation of photocatalytic performance of recycled aggregate concrete in degrading NO2. It was found that replacement rates up to 3%, 30%, and 50% for recycled power, recycled fine aggregate, and recycled coarse aggregate respectively could be applied in concrete mixture design without deteriorating concrete strength. Recycled aggregates contained both positive attributes ("internal curing") and negative effects (e.g., lower hardness) to concrete properties. It was found that 30%-50% of natural coarse aggregate replaced by recycled coarse aggregates coated with TiO2 would significantly improve the photocatalytic performance of concrete measured by degradation rate of NO2. Micro-structures of recycled aggregates observed under microscope indicated that soaking recycled aggregates in TiO2 solution resulted in whiskers that filled the porosity within recycled aggregates which enhanced concrete strength.
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Affiliation(s)
- Yidong Xu
- Ningbo Institute of Technology, Zhejiang University, Ningbo, China
| | - Wei Chen
- Ningbo Institute of Technology, Zhejiang University, Ningbo, China
| | - Ruoyu Jin
- School of Environment and Technology, University of Brighton, Brighton, UK.
| | - Jiansheng Shen
- Ningbo Institute of Technology, Zhejiang University, Ningbo, China
| | - Kirsty Smallbone
- School of Environment and Technology, University of Brighton, Brighton, UK
| | - Chunyang Yan
- Ningbo Institute of Technology, Zhejiang University, Ningbo, China
| | - Lei Hu
- Ningbo Institute of Technology, Zhejiang University, Ningbo, China
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17
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The Utilization of Waste Water from a Concrete Plant in the Production of Cement Composites. BUILDINGS 2017. [DOI: 10.3390/buildings7040120] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Tang P, Brouwers HJH. Integral recycling of municipal solid waste incineration (MSWI) bottom ash fines (0-2mm) and industrial powder wastes by cold-bonding pelletization. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 62:125-138. [PMID: 28274784 DOI: 10.1016/j.wasman.2017.02.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/26/2017] [Accepted: 02/25/2017] [Indexed: 06/06/2023]
Abstract
The cold-bonding pelletizing technique is applied in this study as an integrated method to recycle municipal solid waste incineration (MSWI) bottom ash fines (BAF, 0-2mm) and several other industrial powder wastes. Artificial lightweight aggregates are produced successfully based on the combination of these solid wastes, and the properties of these artificial aggregates are investigated and then compared with others' results reported in literature. Additionally, methods for improving the aggregate properties are suggested, and the corresponding experimental results show that increasing the BAF amount, higher binder content and addition of polypropylene fibres can improve the pellet properties (bulk density, crushing resistance, etc.). The mechanisms regarding to the improvement of the pellet properties are discussed. Furthermore, the leaching behaviours of contaminants from the produced aggregates are investigated and compared with Dutch environmental legislation. The application of these produced artificial lightweight aggregates are proposed according to their properties.
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Affiliation(s)
- P Tang
- Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5612AP Eindhoven, The Netherlands.
| | - H J H Brouwers
- Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5612AP Eindhoven, The Netherlands
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Vieira LDBP, Figueiredo ADD. Evaluation of concrete recycling system efficiency for ready-mix concrete plants. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 56:337-351. [PMID: 27478022 DOI: 10.1016/j.wasman.2016.07.015] [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: 04/04/2016] [Revised: 06/28/2016] [Accepted: 07/11/2016] [Indexed: 06/06/2023]
Abstract
The volume of waste generated annually in concrete plants is quite large and has important environmental and economic consequences. The use of fresh concrete recyclers is an interesting way for the reuse of aggregates and water in new concrete production. This paper presents a study carried out for over one year by one of the largest ready-mix concrete producers in Brazil. This study focused on the evaluation of two recyclers with distinct material separation systems, herein referred to as drum-type and rotary sieve-type equipment. They were evaluated through characterization and monitoring test programs to verify the behaviour of recovered materials (aggregates, water, and slurry). The applicability of the recovered materials (water and aggregates) was also evaluated in the laboratory and at an industrial scale. The results obtained with the two types of recyclers used were equivalent and showed no significant differences. The only exception was in terms of workability. The drum-type recycler generated fewer cases that required increased pumping pressure. The analysis concluded that the use of untreated slurry is unfeasible because of its intense negative effects on the strength and workability of concrete. The reclaimed water, pre-treated to ensure that its density is less than 1.03g/cm(3), can be used on an industrial scale without causing any harm to the concrete. The use of recovered aggregates consequently induces an increase in water demand and cement consumption to ensure the workability conditions of concrete that is proportional to the concrete strength level. Therefore, the viability of their use is restricted to concretes with characteristic strengths lower than 25MPa.
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