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Zhang K, Mao K, Xue J, Chen Z, Du W, Zhang H. Characteristics and risk assessment of heavy metals in groundwater at a typical smelter-contaminated site in Southwest China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 357:124401. [PMID: 38906401 DOI: 10.1016/j.envpol.2024.124401] [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: 01/12/2024] [Revised: 05/28/2024] [Accepted: 06/18/2024] [Indexed: 06/23/2024]
Abstract
To explore the characteristics and evaluate the risk of heavy metals in groundwater at a typical smelter-contaminated site, this study focuses on a representative a historical arsenic smelting plant in Southwest China, where the primary historical products were metallic arsenic (∼1000 tons/year) and arsenic trioxide (∼2000 ton/year). The results demonstrated As and Pb as the main pollutants in soil, and As and Cd as main pollutants in groundwater through soil profiling and quarterly groundwater analysis. The maximum As and Pb in the surface soil were 76800 and 2290 mg/kg, respectively, with As vertically infiltrating the deep gravel-sand layer (18-20 m). The groundwater pollution distribution progressively increased along flow direction, influenced by seasonal surface runoff and infiltration fluctuations. The groundwater pollutant concentrations during the dry season notably surpassed those during the wet season, with maximum As and Cd concentrations of 111.64 mg/L and 19.85 μg/L during the dry season, respectively. Furthermore, the analytic hierarchy process (AHP) was applied to evaluate the comprehensive risk of contaminated-site across pollution source load, regional groundwater intrinsic vulnerability, and evaluation of nearby sensitive receptors. The results revealed that the carcinogenic risk of lead in surface soil was moderate to high, while arsenic posed a high carcinogenic risk, contributing to an overall carcinogenic risk proportion of 89.6% in surface soil. Exposure through groundwater intake was identified as the primary pathway, with carcinogenic and noncarcinogenic risks exceeding those through skin contact. The final weights result demonstrated that the principal risk factors are the intrinsic arsenic load and protective target characteristics of regional groundwater at this site. This study provides a reference for comprehensive assessments of similarly contaminated industrial and smelting sites.
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Affiliation(s)
- Kuankuan Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kang Mao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Jiaqi Xue
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhen Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Wei Du
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China
| | - Hua Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
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2
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You M, Hu Y, Zhou C, Liu G. Speciation Characterization and Environmental Stability of Arsenic in Arsenic-Containing Copper Slag Tailing. Molecules 2024; 29:1502. [PMID: 38611783 PMCID: PMC11012958 DOI: 10.3390/molecules29071502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/19/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
The increasing presence of arsenic-containing impurities within Cu ores can adversely affect the smelting process and aggravate the environmental impact of slag tailing. This study investigates the geochemical, mineralogical, and chemical speciation characteristics to better understand the association and environmental stability of metal(loid)s in copper slag tailing. The results indicate that the predominant chemical compositions of the selected slag tailing are Fe2O3 (54.8%) and SiO2 (28.1%). These tailings exhibit potential for multi-elemental contamination due to elevated concentrations of environmentally sensitive elements. Mineral phases identified within the slag tailings include silicate (fayalite), oxides (magnetite and hematite), and sulfides (galena, sphalerite, arsenopyrite, and chalcopyrite). The consistent presence of silicate, iron, arsenic, and oxygen in the elemental distribution suggests the existence of arsenic within silicate minerals in the form of Si-Fe-As-O phases. Additionally, arsenic shows association with sulfide minerals and oxides. The percentages of arsenite (As(III)) and arsenate (As(V)) within the selected slag tailings are 59.4% and 40.6%, respectively. While the slag tailings are deemed non-hazardous due to the minimal amounts of toxic elements in leachates, proper disposal measures should be taken due to the elevated carbonate-bound levels of As and Cu present in these tailings.
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Affiliation(s)
- Mu You
- School of Biology Engineering, Huainan Normal University, Huainan 232001, China;
| | - Yunhu Hu
- School of Chemistry and Materials Engineering, Huainan Normal University, Huainan 232001, China;
| | - Chuncai Zhou
- School of Resources and Environmental Engineering, Hefei University of Technology, No. 193, Road Tunxi, Hefei 230009, China
| | - Guijian Liu
- School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;
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3
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Feng K, Xu X, Ke Q, Ding J, Zhao L, Qiu H, Cao X. Mineralogical transformation of arsenic at different copper smelting workshops: The impact on arsenic bioaccessibility. CHEMOSPHERE 2024; 352:141502. [PMID: 38382715 DOI: 10.1016/j.chemosphere.2024.141502] [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: 10/29/2023] [Revised: 01/30/2024] [Accepted: 02/18/2024] [Indexed: 02/23/2024]
Abstract
Soil arsenic (As) contamination associated with the demolition of smelting plants has received increasing attention. Soil As can source from different industrial processes, and also participate in soil weathering, making its speciation rather complex. This study combined the usage of chemical sequential extraction and advanced spectroscopic techniques, e.g., time of flight secondary ion mass spectrometry (ToF-SIMS), to investigate the mineralogical transformation of soil As at different processing sites from a typical copper smelting plant in China. Results showed that the stability of arsenic species decreased following the processes of storage, smelting, and flue gas treatment. Arsenic in the warehouse area was incorporated into pyrite (FeS2) as well as its secondary minerals such as jarosite (KFe3(SO4)2(OH)6). At the smelting area, a large proportion of As was adsorbed by iron oxides from smelting slags, while some As existed in stable forms like orpiment (As2S3). At the acid-making area, more than half of As was adsorbed on amorphous iron oxides, and some were adsorbed on the flue gas desulfurization gypsum. More importantly, over 86% of the As belonged to non-specifically and specifically adsorbed fractions was found to be bioaccessible, highlighting the gypsum-adsorbed As one of the most hazardous species in smelting plant soils. Our findings indicated the importance of iron oxides in As retention and suggested the potential health risk of gypsum-adsorbed As. Such detailed knowledge of As speciation and bioaccessibility is vital for the management and remediation of As-contaminated soils in smelting plants.
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Affiliation(s)
- Kanghong Feng
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaoyun Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Qiang Ke
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiaxin Ding
- Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ling Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hao Qiu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xinde Cao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
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Liu Y, Molinari S, Dalconi MC, Valentini L, Bellotto MP, Ferrari G, Pellay R, Rilievo G, Vianello F, Salviulo G, Chen Q, Artioli G. Mechanistic insights into Pb and sulfates retention in ordinary Portland cement and aluminous cement: Assessing the contributions from binders and solid waste. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131849. [PMID: 37393826 DOI: 10.1016/j.jhazmat.2023.131849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/31/2023] [Accepted: 06/12/2023] [Indexed: 07/04/2023]
Abstract
Identifying immobilization mechanisms of potentially toxic elements (PTEs) is of paramount importance in the field application of solidification/stabilization. Traditionally, demanding and extensive experiments are required to better access the underlying retention mechanisms, which are usually challenging to quantify and clarify precisely. Herein, we present a geochemical model with parametric fitting techniques to reveal the solidification/stabilization of Pb-rich pyrite ash through conventional (ordinary Portland cement) and alternative (calcium aluminate cement) binders. We found that ettringite and calcium silicate hydrates exhibit strong affinities for Pb at alkaline conditions. When the hydration products are unable to stabilize all the soluble Pb in the system, part of the soluble Pb may be immobilized as Pb(OH)2. At acidic and neutral conditions, hematite from pyrite ash and newly-formed ferrihydrite are the main controlling factors of Pb, coupled with anglesite and cerussite precipitation. Thus, this work provides a much-needed complement to this widely-applied solid waste remediation technique for the development of more sustainable mixture formulations.
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Affiliation(s)
- Yikai Liu
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129 Padua, Italy
| | - Simone Molinari
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129 Padua, Italy.
| | - Maria Chiara Dalconi
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129 Padua, Italy
| | - Luca Valentini
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129 Padua, Italy
| | | | | | | | - Graziano Rilievo
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy
| | - Fabio Vianello
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy
| | - Gabriella Salviulo
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129 Padua, Italy
| | - Qiusong Chen
- Sinosteel Maanshan General Institute of Mining Research Co., Ltd., Maanshan 24300, China; School of Resources and Safety Engineering, Central South University, Lushan South Road 932, 410083 Hunan, China
| | - Gilberto Artioli
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129 Padua, Italy
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Comparative Study for Flue Dust Stabilization in Cement and Glass Materials: A Stability Assessment of Arsenic. MINERALS 2022. [DOI: 10.3390/min12080939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Arsenic is a poisonous element and its super mobility can pose a major threat to the environment and human beings. Disposed arsenic-bearing waste or minerals over time may release arsenic into the groundwater, soil and then the food chain. Consequently, safe landfill deposition should be carried out to minimize arsenic bleeding. Cement-based stabilization/solidification and glass vitrification are two important methods for arsenic immobilization. This work compares the stability and intrinsic leaching properties of sequestered arsenic by cement encapsulation and glass vitrification of smelter high-arsenic flue dust (60% As2O3) and confirms if they meet or exceed the requirement of landfill disposition over a range of environmentally relevant conditions. The toxicity characterization leaching procedure (TCLP, 1311), synthetic precipitation leaching procedure (SPLP, 1312) and Australian standard (Aus. 4439.3) in short-term (18 h) and mass transfer from monolithic material using a semi-dynamic leaching tank (1315) in longer-term (165 days) were employed to assess arsenic immobility characteristic in three arsenic-cement (2%, 8.4% and 14.4%) and arsenic-glass (11.7%) samples. Moreover, calcium release from different matrices has been taken into consideration as a contributor to arsenic bleeding. Based on the USEPA guidelines, samples can be acceptable for landfilling only if As release is < 5 mg/L. Results obtained from short-term leaching were almost similar for both cement and glass materials. However, high calcium release was observed from the cement-encapsulated materials. The pH of leachates after the test was highly alkaline for encapsulated materials; however, in glass material it was near neutral or slightly acidic. Method 1315 tests made a huge difference between the two materials and confirmed that cement encapsulation is not the best method for landfilling arsenic waste due to the high arsenic and calcium release over time with alkaline pH. However, glass material has shown promising results, i.e., the insignificant release of arsenic over time with an acceptable change in pH value. Overall, arsenic sequestration in glass is a better option compared with the cement-based solidification process.
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Chen J, Zhang W, Ma B, Che J, Xia L, Wen P, Wang C. Recovering metals from flue dust produced in secondary copper smelting through a novel process combining low temperature roasting, water leaching and mechanochemical reduction. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128497. [PMID: 35739678 DOI: 10.1016/j.jhazmat.2022.128497] [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: 12/07/2021] [Revised: 01/28/2022] [Accepted: 02/12/2022] [Indexed: 06/15/2023]
Abstract
Flue dust from secondary copper smelting (FDSC) is a hazardous waste as well as a secondary resource due to the high content of Cl, Br, and valuable metals (Pb, Cu, Zn, Cd). Herein, a novel process, combined low-temperature roasting, water leaching, and mechanochemical reduction, was developed for recovering metals from the FDSC. The phase conversion and behavior of the main elements in the whole process were explored based on thermodynamic analysis, experimental research, and various characterization. First, thermodynamics calculation revealed that adding H2SO4 could significantly decrease the roasting temperature and promote the generation of soluble metal sulfates. The experimental results showed that more than 99% of Cl and Br were removed by roasting at 325 °C and 1.5 times H2SO4 addition. Subsequently, the Cu, Zn, and Cd were almost completely leached by water under the conditions of 80 ℃, 2 h and L/S = 5 mL·g-1, while Pb was rejected and enriched in the residue. Finally, using iron powder as a reductant, 96.7% of PbSO4 was reduced to elemental lead at room temperature with the aid of mechanical force. The findings illustrated that the recovery performance of metals and environmental benefits will be greatly improved by the proposed process.
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Affiliation(s)
- Jun Chen
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Wenjuan Zhang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | - Baozhong Ma
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | - Jianyong Che
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Liu Xia
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Peicheng Wen
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Chengyan Wang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
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7
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Wang H, Zhu R, Dong K, Zhang S, Zhao R, Jiang Z, Lan X. An experimental comparison: Horizontal evaluation of valuable metal extraction and arsenic emission characteristics of tailings from different copper smelting slag recovery processes. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128493. [PMID: 35739674 DOI: 10.1016/j.jhazmat.2022.128493] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 06/15/2023]
Abstract
This study comprehensively investigated arsenic's enrichment, distribution, and characteristics in tailings. XRD and SEM-EDS characterized the phase and morphology of tailings from various smelting processes. At the same time, the embedding characteristics of arsenic in the ore phase were analyzed by EPMA. The differences between arsenic's leading ore phase carriers in different recovery processes were found. It was discussed that this phenomenon would be related to the element-binding ability and the precipitation priority of the ore phase. The occurrence state of arsenic was discussed by sequential chemical extraction experiments. The proportion of leachable arsenic is higher than the low-risk limit, whatever which smelting method is adopted, which leads to high environmental risk. In the experiment of comparing the leaching toxicity of tailings by different leaching methods, the arsenic concentration in the leaching solution of tailings recovered by the flotation method exceeds the specified safety range. Although the tailings after reduction smelting did not show high leaching toxicity, a large number of accumulations also would not represent absolute safety.
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Affiliation(s)
- Hongyang Wang
- University of Science and Technology Beijing, School of Metallurgical and Ecological Engineering, Beijing 100083, China; Beijing Key Laboratory for special melting and preparation of high-end metal materials, Beijing 100083, China
| | - Rong Zhu
- University of Science and Technology Beijing, School of Metallurgical and Ecological Engineering, Beijing 100083, China; Beijing Key Laboratory for special melting and preparation of high-end metal materials, Beijing 100083, China
| | - Kai Dong
- University of Science and Technology Beijing, School of Metallurgical and Ecological Engineering, Beijing 100083, China; Beijing Key Laboratory for special melting and preparation of high-end metal materials, Beijing 100083, China.
| | - Siqi Zhang
- Beijing Key Laboratory for special melting and preparation of high-end metal materials, Beijing 100083, China; University of Science and Technology Beijing, School of Civil and Resources Engineering, Beijing 100083, China
| | - Ruimin Zhao
- University of Science and Technology Beijing, School of Metallurgical and Ecological Engineering, Beijing 100083, China; Beijing Key Laboratory for special melting and preparation of high-end metal materials, Beijing 100083, China
| | - Zhenqiang Jiang
- University of Science and Technology Beijing, School of Metallurgical and Ecological Engineering, Beijing 100083, China; Beijing Key Laboratory for special melting and preparation of high-end metal materials, Beijing 100083, China
| | - Xinyi Lan
- Beijing Key Laboratory for special melting and preparation of high-end metal materials, Beijing 100083, China; University of Science and Technology Beijing, School of Automation and Electrical Engineering, Beijing 100083, China
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Nitric Acid Dissolution of Tennantite, Chalcopyrite and Sphalerite in the Presence of Fe (III) Ions and FeS 2. MATERIALS 2022; 15:ma15041545. [PMID: 35208081 PMCID: PMC8876106 DOI: 10.3390/ma15041545] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/02/2022] [Accepted: 02/14/2022] [Indexed: 02/01/2023]
Abstract
This paper describes the nitric acid dissolution process of natural minerals such as tennantite, chalcopyrite and sphalerite, with the addition of Fe (III) ions and FeS2. These minerals are typical for the ores of the Ural deposits. The effect of temperature, nitric acid concentration, time, additions of Fe (III) ions and FeS2 was studied. The highest dissolution degree of sulfide minerals (more than 90%) was observed at a nitric acid concentration of 6 mol/dm3, an experiment time of 60 min, a temperature of 80 °C, a concentration of Fe (III) ions of 16.5 g/dm3, and an addition of FeS2 to the total mass minerals at 1.2:1 ratio. The most significant factors in the break-down of minerals were the nitric acid concentration, the concentration of Fe (III) ions and the amount of FeS2. Simultaneous addition of Fe (III) ions and FeS2 had the greatest effect on the leaching process. It was also established that FeS2 can be an alternative catalytic surface for copper sulfide minerals during nitric acid leaching. This helps to reduce the influence of the passivation layer of elemental sulfur due to the galvanic linkage formed between the minerals, which was confirmed by SEM-EDX.
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Chemical Composition Data of the Main Stages of Copper Production from Sulfide Minerals in Chile: A Review to Assist Circular Economy Studies. MINERALS 2022. [DOI: 10.3390/min12020250] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The mining industry has faced significant challenges to maintaining copper production technically, economically, and environmentally viable. Some of the major limitations that must be overcome in the coming years are the copper ore grade decline due to its intense exploitation, the increasing requirements for environmental protection, and the need to expand and construct new tailings dams. Furthermore, the risk of a supply crisis of critical metals, such as antimony and bismuth, has prompted efforts to increase their extraction from secondary resources in copper production. Therefore, improving conventional processes and developing new technologies is crucial to satisfying the world’s metal demands, while respecting the policies of environmental organizations. Hence, it is essential that the chemical composition of each copper production stage is known for conducting these studies, which may be challenging due to the huge variability of concentration data concerning the ore extraction region, the process type, and the operational conditions. This paper presents a review of chemical composition data of the main stages of copper production from sulfide minerals, such as (1) copper minerals, (2) flotation tailings, (3) flotation concentrates, (4) slags and (5) flue dust from the smelting/converting stage, (6) copper anodes, (7) anode slimes, (8) contaminated electrolytes from the electrorefining stage, (9) electrolytes cleaned by ion-exchange resins, and (10) elution solutions from the resins. In addition, the main contributions of recent works on copper production are summarized herein. This study is focused on production sites from Chile since it is responsible for almost one-third of the world’s copper production.
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Tuhý M, Ettler V, Rohovec J, Matoušková Š, Mihaljevič M, Kříbek B, Mapani B. Metal(loid)s remobilization and mineralogical transformations in smelter-polluted savanna soils under simulated wildfire conditions. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 293:112899. [PMID: 34089961 DOI: 10.1016/j.jenvman.2021.112899] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/06/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
The surroundings of mines and smelters may be exposed to wildfires, especially in semi-arid areas. The temperature-dependent releases of metal(loid)s (As, Cd, Cu, Pb, Zn) from biomass-rich savanna soils collected near a Cu smelter in Namibia have been studied under simulated wildfire conditions. Laboratory single-step combustion experiments (250-850 °C) and experiments with a continuous temperature increase (25-750 °C) were coupled with mineralogical investigations of the soils, ashes, and aerosols. Metals (Cd, Cu, Pb, Zn) were released at >550-600 °C, mostly at the highest temperatures, where complex aerosol particles, predominantly composed of slag-like aggregates, formed. In contrast, As exhibited several emission peaks at ~275 °C, ~370-410 °C, and ~580 °C, reflecting its complex speciation in the solid phase and indicating its remobilization, even during wildfires with moderate soil heating. At <500 °C, As was successively released via the transformation of As-bearing hydrous ferric oxides, arsenolite (As2O3) grains attached to the organic matter fragments, metal arsenates, and/or As-bearing apatite, followed by the thermal decomposition of enargite (Cu3AsS4) at >500 °C. The results indicate that the active and abandoned mining and smelting sites, especially those highly enriched in As, should be protected against wildfires, which can be responsible for substantial As re-emissions.
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Affiliation(s)
- Marek Tuhý
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00, Prague 2, Czech Republic.
| | - Vojtěch Ettler
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00, Prague 2, Czech Republic.
| | - Jan Rohovec
- Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojová 269, 165 00, Prague 6, Czech Republic
| | - Šárka Matoušková
- Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojová 269, 165 00, Prague 6, Czech Republic
| | - Martin Mihaljevič
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00, Prague 2, Czech Republic
| | - Bohdan Kříbek
- Czech Geological Survey, Geologická 6, 152 00, Prague 5, Czech Republic
| | - Ben Mapani
- Department of Mining and Process Engineering, Faculty of Engineering, Namibia University of Science and Technology, Private Bag, 13388, Windhoek, Namibia
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11
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Zhang E, Zhou K, Zhang X, Peng C, Chen W, He D. Separation and recovery of arsenic from As, Cu, and Zn rich leaching liquor using a reduction-crystallization approach. RSC Adv 2021; 11:22426-22432. [PMID: 35480809 PMCID: PMC9034198 DOI: 10.1039/d1ra03270d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/20/2021] [Indexed: 11/21/2022] Open
Abstract
As, Cu, and Zn rich leaching liquor is generated in the leaching process of copper dust, which contains various metals with high recovery value. Herein, an approach for the direct separation and recovery of arsenic from As, Cu, and Zn rich leaching liquor was proposed. The approach includes two steps, namely SO2 reduction and arsenic crystallization. The factors affecting the reduction of As(v) to As(iii) were investigated, including the pH, SO2 dosage, and reduction temperature. In the crystallization stage, the impacts of sulfuric acid consumption and temperature on the crystallization of arsenic (As2O3) were studied. The results show that the optimal H+ concentration, temperature, and SO2 input for the arsenic reduction were 3.95 mol L-1, 45 °C, and 1.14 L g-1 As(v), respectively. While the optimal temperature and sulfuric acid dosage in As recovery process were 5 °C and 0.1 L L-1 leaching liquor, respectively. Under these conditions, the As2O3 recovery percentage reached 96.53%, and the losses of Cu and Zn were only 3.12% and 0.75%, respectively. The precipitate contained 96.72% of As2O3, 0.83% of Cu, and 0.13% Zn. Compared with the traditional technologies, this new method can improve the recovery efficiency of As2O3 and reduce the loss percentage of other valuable metals (Cu and Zn).
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Affiliation(s)
- Erjun Zhang
- School of Metallurgy and Environment, Central South University Changsha 410083 China
| | - Kanggen Zhou
- School of Metallurgy and Environment, Central South University Changsha 410083 China
| | - Xuekai Zhang
- School of Metallurgy and Environment, Central South University Changsha 410083 China
- College of Chemistry and Chemical Engineering, Central South University Changsha 410083 China
| | - Changhong Peng
- School of Metallurgy and Environment, Central South University Changsha 410083 China
| | - Wei Chen
- School of Metallurgy and Environment, Central South University Changsha 410083 China
| | - Dewen He
- School of Metallurgy and Environment, Central South University Changsha 410083 China
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12
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Zhang W, Che J, Xia L, Wen P, Chen J, Ma B, Wang C. Efficient removal and recovery of arsenic from copper smelting flue dust by a roasting method: Process optimization, phase transformation and mechanism investigation. JOURNAL OF HAZARDOUS MATERIALS 2021; 412:125232. [PMID: 33951866 DOI: 10.1016/j.jhazmat.2021.125232] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/05/2021] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
The efficient removal and recovery of arsenic from copper smelting flue dust have received widespread attention due to its extremely high toxicity and carcinogenicity. In this research, a roasting method used for treating the dust at a relatively low temperature (300-400 ℃), with adding sulfuric acid and bitumite, was proposed, in which the reduction of As(Ⅴ) and oxidation of arsenic sulfides were achieved simultaneously. It was proved by thermodynamic analysis and experiments that adding sulfuric acid was favorable for the removal of arsenic, through enhancing the thermodynamic driving force and promoting the transformation of arsenate and arsenic sulfides to As2O3. The phase transformation of arsenic was analyzed using XRD, SEM-EDS and XPS, which indicated that coal addition, roasting temperature and H2SO4 dosage play essential roles in arsenic removal. Based on the lab-scale experiments, the optimal conditions for arsenic removal were found to be at the roasting temperature of 300-400 °C, roasting time of 2-3 h, coal addition of 5% and H2SO4 dosage of 0.2-0.3 mL/g. Around 98% of arsenic was volatilized from the dust, while arsenic content in the residue was decreased to 0.57%. Eventually, arsenic was recovered as As2O3 with a high purity of 99.05%.
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Affiliation(s)
- Wenjuan Zhang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jianyong Che
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Liu Xia
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Peicheng Wen
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jun Chen
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Baozhong Ma
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Chengyan Wang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
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Yan K, Liu L, Zhao H, Tian L, Xu Z, Wang R. Study on Extraction Separation of Thioarsenite Acid in Alkaline Solution by CO 3 2 - -Type Tri-n-Octylmethyl-Ammonium Chloride. Front Chem 2021; 8:592837. [PMID: 33681140 PMCID: PMC7927356 DOI: 10.3389/fchem.2020.592837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 12/08/2020] [Indexed: 11/13/2022] Open
Abstract
To overcome the problem of arsenic separation and enrichment from an alkaline leaching solution in arsenic-containing dust, a CO 3 2 - -type tri-n-octylmethyl-ammonium chloride (TOMAC) method for extracting thioarsenite is proposed in this paper. Considering an alkaline leaching solution as the research object, after vulcanization pretreatment, TOMAC transformation and organic phase saturated extraction capacity were measured, and the extraction mechanism was preliminarily studied. First, Cl--type quaternary ammonium salt was effectively transformed to HCO 3 - -type by treating organic phase with saturated NaHCO3five times. TOMAC was effectively transformed from HCO 3 - to CO 3 2 - type by alkaline washing with 1.0 mol/l NaOH solution; this washing was repeated thrice. Thereafter, the effects of organic phase composition, phase ratio, extraction time, and temperature on the extraction and separation of arsenic were investigated. The results show that under the conditions of 30% CO 3 2 - -type TOMAC + 15% sec-octanol + 55% sulfonated kerosene, VO/VA = 1/1, and 5 min extraction at room temperature, the single-stage extraction rate of AsIII is 85.2%. The AsIII concentration in raffinate can be reduced to less than 1.33 × 10-3 mol/l by four-stage countercurrent extraction, and the extraction rate of AsIII can exceed 98.4%.
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Affiliation(s)
- Kang Yan
- School of Metallurgical Engineering, Jiangxi University of Science and Technology, Ganzhou, China
| | - Liping Liu
- School of Metallurgical Engineering, Jiangxi University of Science and Technology, Ganzhou, China
| | - Hongxing Zhao
- School of Metallurgical Engineering, Jiangxi University of Science and Technology, Ganzhou, China
| | - Lei Tian
- School of Metallurgical Engineering, Jiangxi University of Science and Technology, Ganzhou, China.,Henan Yuguang Gold and Lead Group Co., Ltd., Jiyuan, China
| | - Zhifeng Xu
- President Office, Jiangxi College of Applied Technology, Ganzhou, China
| | - Ruixiang Wang
- School of Metallurgical Engineering, Jiangxi University of Science and Technology, Ganzhou, China
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Zhang Y, Feng X, Jin B. An effective separation process of arsenic, lead, and zinc from high arsenic-containing copper smelting ashes by alkali leaching followed by sulfide precipitation. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2020; 38:1214-1221. [PMID: 32515295 DOI: 10.1177/0734242x20927473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Separation of arsenic and valuable metals (Pb, Zn, Cu, Bi, Sn, In, Ag, Sb, etc.) is a core problem for effective utilization of high arsenic-containing copper smelting ashes (HACSA). This study developed an effective separation process of arsenic, lead, and zinc from HACSA via alkali leaching followed by sulfide precipitation. The separation behaviors and optimum conditions for alkali leaching of arsenic and sulfide precipitation of lead and zinc were established respectively as follows: NaOH concentration 3.81 M; temperature 80°C; time 90 minutes; liquid-to-solid ratio 4:1; agitation speed 450 revolutions/minute (r/min) and 2.0 times of theoretical quantity of sodium sulfide (Na2S); temperature 70°C; and time 60 minutes. The results indicated that the leaching rates of As, Pb, and Zn were 92.4%, 36.9% and 13.4%, respectively. More than 99% of lead and zinc were precipitated from the alkali leachate. The scanning electron microscopy/energy dispersive X-ray spectroscopy study confirmed that arsenic was dissolved from HACSA into the alkali leachate. Furthermore, lead and zinc were precipitated as sulfides from the alkali leachate. The proposed process was a good technique for separation of arsenic and enrichment of valuable metals for further centralized treatment separately. It provided high separation efficiency of arsenic and valuable metals, as well as low environmental pollution.
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Affiliation(s)
- Yuhui Zhang
- These authors contributed equally to this work
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15
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Wu C, Mahandra H, Ghahreman A. Novel Continuous Column Process for As(III) Oxidation from Concentrated Acidic Solutions with Activated Carbon Catalysis. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c00470] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chengqian Wu
- Robert M. Buchan Department of Mining, Queen’s University, 25 Union Street, Kingston, Ontario K7L3N6, Canada
| | - Harshit Mahandra
- Robert M. Buchan Department of Mining, Queen’s University, 25 Union Street, Kingston, Ontario K7L3N6, Canada
| | - Ahmad Ghahreman
- Robert M. Buchan Department of Mining, Queen’s University, 25 Union Street, Kingston, Ontario K7L3N6, Canada
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Selective Separation of Arsenic from Lead Smelter Flue Dust by Alkaline Pressure Oxidative Leaching. MINERALS 2019. [DOI: 10.3390/min9050308] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study investigated the feasibility of using an alkaline pressure oxidative leaching process to treat lead smelter flue dust containing extremely high levels of arsenic with the aim of achieving the selective separation of arsenic. The effects of different parameters including NaOH concentration, oxygen partial pressure, liquid-to-solid ratio, temperature, and time for the extraction of arsenic were investigated based on thermodynamic calculation. The results indicated that the leaching efficiency of arsenic reached 95.6% under the optimized leaching conditions: 80 g/L of NaOH concentration, 1.0 MPa of oxygen partial pressure, 8 mL/g of liquid-to-solid ratio, 120 °C of temperature, 2.0 h of time. Meanwhile, the leaching efficiencies of antimony, cadmium, indium and lead were less than 4.0%, basically achieving the selective separation of arsenic from lead smelter flue dust. More than 99.0% of arsenic was converted into calcium arsenate product and thus separated from the leach solution by a causticization process with CaO after other metal impurities were removed from the solution with the addition of Na2S. The optimized causticization conditions were established as: 4.0 of the mole ratio of calcium to arsenic, temperature of 80 °C, reaction time of 2.0 h. The resulting product of calcium arsenate may be used for producing metallic arsenic.
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Ettler V, Cihlová M, Jarošíková A, Mihaljevič M, Drahota P, Kříbek B, Vaněk A, Penížek V, Sracek O, Klementová M, Engel Z, Kamona F, Mapani B. Oral bioaccessibility of metal(loid)s in dust materials from mining areas of northern Namibia. ENVIRONMENT INTERNATIONAL 2019; 124:205-215. [PMID: 30654327 DOI: 10.1016/j.envint.2018.12.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/13/2018] [Accepted: 12/13/2018] [Indexed: 06/09/2023]
Abstract
Ore mining and processing in semi-arid areas is responsible for the generation of metal(loid)-containing dust, which is easily transported by wind to the surrounding environment. To assess the human exposure to dust-derived metal(loid)s (As, Cd, Cu, Pb, Sb, Zn), as well as the potential risks related to incidental dust ingestion, we studied mine tailing dust (n = 8), slag dust (n = 5) and smelter dust (n = 4) from old mining and smelting sites in northern Namibia (Kombat, Berg Aukas, Tsumeb). In vitro bioaccessibility testing using extraction in simulated gastric fluid (SGF) was combined with determination of grain-size distributions, chemical and mineralogical characterizations and leaching tests conducted on original dust samples and separated PM10 fractions. The bulk and bioaccessible concentrations of the metal(loid)s were ranked as follows: mine tailing dusts < slag dusts ≪ smelter dusts. Extremely high As and Pb bioaccessibilities in the smelter dusts were caused by the presence of highly soluble phases such as arsenolite (As2O3) and various metal-arsenates unstable under the acidic conditions of SGF. The exposure estimates calculated for an adult person of 70 kg at a dust ingestion rate of 50 mg/day indicated that As, Pb (and also Cd to a lesser extent) grossly exceeded tolerable daily intake limits for these contaminants in the case of slag and smelter dusts. The high risk for smelter dusts has been acknowledged, and the safety measures currently adopted by the smelter operator in Tsumeb are necessary to reduce the staff's exposure to contaminated dust. The exposure risk for the local population is only important at the unfenced disposal sites at Berg Aukas, where the PM10 exhibited high levels of bioaccessible Pb.
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Affiliation(s)
- Vojtěch Ettler
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic.
| | - Markéta Cihlová
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Alice Jarošíková
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Martin Mihaljevič
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Petr Drahota
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Bohdan Kříbek
- Czech Geological Survey, Geologická 6, 152 00 Prague 5, Czech Republic
| | - Aleš Vaněk
- Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6, Czech Republic
| | - Vít Penížek
- Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6, Czech Republic
| | - Ondra Sracek
- Department of Geology, Faculty of Science, Palacký University in Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Mariana Klementová
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež 1001, 250 68 Řež, Czech Republic
| | - Zbyněk Engel
- Department of Physical Geography and Geoecology, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Fred Kamona
- Department of Geology, Faculty of Science, University of Namibia, Private Bag 13301, Windhoek, Namibia
| | - Ben Mapani
- Department of Geology, Faculty of Science, University of Namibia, Private Bag 13301, Windhoek, Namibia
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18
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Gu K, Li W, Han J, Liu W, Qin W, Cai L. Arsenic removal from lead-zinc smelter ash by NaOH-H2O2 leaching. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2018.07.023] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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