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Xie Z, Mahmood Q, Zhang S. Copper recovery from waste printed circuit boards using pyrite as the bioleaching substrate. Environ Sci Pollut Res Int 2024:10.1007/s11356-024-33536-y. [PMID: 38698096 DOI: 10.1007/s11356-024-33536-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/27/2024] [Indexed: 05/05/2024]
Abstract
Waste printed circuit boards (WPCBs) can be bioleached for Cu recovery, but lack of substrate for the bioleaching culture. In this study, using pyrite as a bacterial substrate for bioleaching WPCBs and recovering Cu was explored. The results showed that the WPCBs bioleaching using pyrite as the bacterial substrate was feasible. Mechanical crushing was a suitable WPCBs pretreatment method. The optimal WPCBs and pyrite pulp densities were respectively found to be 1.25% (w/v) and 1.0% (w/v), and the suitable nitrogen source ratio ((NH4)2SO4: (NH4)2HPO4) was deemed as 2 g/L: 2 g/L, achieving a Cu2+ leaching efficiency of 95.60 ± 1.57% in 14 d. Copper in the bioleaching solution can be directly recovery via electrodeposition. The Cu recovery efficiency in 60 min was up to 92.19 ± 1.35% under the optimal condition that the initial Cu2+ concentration and pH were respectively set at 7.34 g/L and 2.75, and the current density was set at 200 A/m2. Copper was found as the dominant metal in the cathode deposits, existing in the form of Cu and Cu2O. This work provided a novel approach for bioleaching WPCBs and recovering Cu.
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Affiliation(s)
- Zexiang Xie
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, People's Republic of China
| | - Qaisar Mahmood
- Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, Abbottabad, 22060, Pakistan
| | - Shaohui Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, People's Republic of China.
- Hubei Key Laboratory of Fuel Cell, Wuhan University of Technology, Wuhan, 430070, People's Republic of China.
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2
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Zhang S, Cao J, Yang P, Xie Y, Wang H, Mao Y, Ning K, Zhang Q. Adsorption and aggregation of Cu 2+ on carboxymethylated sugarcane bagasse: Adsorption behavior and mechanism. J Hazard Mater 2024; 465:133297. [PMID: 38141295 DOI: 10.1016/j.jhazmat.2023.133297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/25/2023]
Abstract
Abundant biomass resources provide us with sufficient material basis, while a large amount of bio-waste is also produced and the high-value utilization of bio-waste is still highly desirable. Herein, we reported a facile one-pot fabrication approach towards efficient utilization of sugarcane bagasse via carboxymethylation to adsorb and recycle Cu2+ ions. The modified sugarcane bagasse possessed outstanding adsorption efficiency, with a maximum capacity of 263.7 mg g-1, owing to the functional groups such as carboxyl and hydroxyl groups, as well as aromatic structure. It was noted that the carboxymethylated sugarcane bagasse (MSB40) swelled rapidly when suffering Cu2+ ions solution, and more adsorption sites were available since the physical diffusion barrier was removed, thereby enhancing the absorption capacity. Interestingly, Cu2+ ions could induce the aggregation of MSB40 due to the Cu2+ ions compress colloid double layer, neutralizes surface charges, which benefited the following separation process. Ultimately, copper oxide was recovered and the purity reached 97.9%. Additionally, in the presence of both Ca2+ and Mg2+ ions, MSB40 exhibited excellent selectivity for the adsorption of Cu2+ ions. This strategy offers a facile and novel clue for the high-value utilization of bio-waste and the recovery of copper for biomaterial and environmental applications.
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Affiliation(s)
- Shiping Zhang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, PR China; National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Jinyan Cao
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, PR China; National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Peng Yang
- Department of Health Products Technical Research and Development Center, Yunnan Baiyao Group Co. Ltd, Kunming 650500, PR China
| | - Yu Xie
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, PR China; National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Huiming Wang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, PR China; National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Yufeng Mao
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, PR China; National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Kegong Ning
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, PR China; Department of Health Products Technical Research and Development Center, Yunnan Baiyao Group Co. Ltd, Kunming 650500, PR China.
| | - Qiulin Zhang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, PR China; National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming University of Science and Technology, Kunming 650500, PR China.
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3
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Chen W, Tang H, Yin S, Wang L, Zhang M. Copper recovery from low-grade copper sulfides using bioleaching and its community structure succession in the presence of Sargassum. J Environ Manage 2024; 349:119549. [PMID: 37979390 DOI: 10.1016/j.jenvman.2023.119549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 10/17/2023] [Accepted: 11/04/2023] [Indexed: 11/20/2023]
Abstract
Bioleaching characteristics and bacterial community structure were studied during low-grade copper sulfide ores bioleaching in the presence of pretreated Sargassum (PSM). Results indicated that proportion of attached bacteria and copper recovery were improved by using appropriate-dosage PSM. High copper recovery (82.99%) and low Fe3+ concentration were obtained when 150 mg L-1 PSM was used. Precipitation, such as KFe3(SO4)2(OH)6 and (H3O)Fe3(SO4)2(OH)6, was not found in samples used PSM according to XRD, FTIR and TG analyses, which may result from less passivation layer formed by Fe3+ hydrolysis. I- contained in PSM can act as the reductant to convert Fe3+ into Fe2+, which can reduce Fe3+ hydrolysis and adjust Eh value. Bacterial community structure was influenced significantly by PSM according to the 16 S rDNA analysis. Acidithiobacillus ferrooxidans dominated proportion of bacterial community throughout bioleaching process, whose proportion reached 89.1091% after 14 days in sample added 150 mg L-1 PSM.
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Affiliation(s)
- Wei Chen
- Key Laboratory of Ministry of Education for High-Efficient Mining and Safety of Metal, University of Science and Technology Beijing, Beijing, 100083, China; School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Huiyang Tang
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Shenghua Yin
- Key Laboratory of Ministry of Education for High-Efficient Mining and Safety of Metal, University of Science and Technology Beijing, Beijing, 100083, China; School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Leiming Wang
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Ming Zhang
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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4
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Fang H, Zeng D, Chen S, Ye X. Unlocking sustainable solutions: controlled Cu 2+ dosing enables efficient recovery and reuse of high-purity copper pyrophosphate from electroplating wastewater. Environ Sci Pollut Res Int 2023; 30:119893-119902. [PMID: 37932614 DOI: 10.1007/s11356-023-30699-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/20/2023] [Indexed: 11/08/2023]
Abstract
The electroplating process of copper pyrophosphate (Cu2P2O7) results in the production of a large volume of wastewater that contains a high concentration of copper (Cu). Currently, conventional lime precipitation creates a substantial amount of secondary pollution, which adds extra economic and environmental burdens. In this study, we suggest a straightforward method for on-site recovery of Cu from Cu2P2O7 electroplating wastewater. By optimizing various parameters, characterizing the resulting product, assessing its electroplating capabilities, and analyzing the speciation during the reaction, we comprehensively investigated the feasibility and mechanism of this technique. The results demonstrated that, under the optimal conditions (Cu/P molar ratio of 0.96, pH of 5.0, and a reaction time of 5.0 min), the concentration of residual Cu remained stable between 22.2 and 27.7 mg/L, even when the initial Cu concentrations varied. The addition of Cu triggered a series of hydrolysis and ionization reactions, primarily leading to the formation of Cu2P2O7·3H2O. The harvested Cu2P2O7·3H2O proved to be suitable for practical electroplating applications, exhibiting comparable performance to commercially available Cu2P2O7·3H2O. This demonstrates the feasibility of recovering high-purity Cu2P2O7·3H2O from copper electroplating wastewater, offering a promising approach for on-site copper reuse and concurrently reducing the demand for natural copper resources. Furthermore, this approach significantly reduces the generation of solid waste, aligning with the principles of sustainable development.
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Affiliation(s)
- Hongda Fang
- College of Harbour and Coastal Engineering, Jimei University, Xiamen, 361021, China.
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
| | - Di Zeng
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Shaohua Chen
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Xin Ye
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
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5
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Xia Q, Song Q, Xu Z. Electrorefining and electrodeposition for metal separation and purification from polymetallic concentrates after waste printed circuit board smelting. Waste Manag 2023; 158:146-152. [PMID: 36709680 DOI: 10.1016/j.wasman.2023.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 01/01/2023] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
Multi metal recycling from waste printed circuit boards (WPCBs) is attractive for resource conservation and sustainability. While smelting is commonly adopted to produce polymetallic concentrates from WPCBs, current processes cost oxidation smelting and fire refining followed by electrorefining to deport co-existing base metals and recover copper, which can cause substantial metal losses, long steps, and lack of effective methods for subsequent base metal recycling. Here, direct electrorefining of polymetallic concentrates (Cu-Ni-Fe-Pb-sn-Au-Ag) combined with electrodeposition was investigated to realize multi metal separation and purification. It was found that direct electrorefining of concentrates in H2SO4/CuSO4 electrolyte at 0.4 V realized >98% base metal dissolution and copper production (∼99% purity), serving as a combined metal leaching and copper electrowinning procedure. PbSO4-SnO2-Cu5FeS4 precipitate was formed in anode slime, with Ag-Au enriched by 8.5-61 times. Analysis on subsequent selective metal electrodeposition revealed the blocking effect of Zn2+ and overlapped potential region of Fe2+-Ni2+, emphasizing the importance of Zn and Fe pre-separation during smelting and chemical precipitation. Electrodeposition experiments demonstrated high selectivity for Cu and Ni at 0.05 and -0.7 V, where Ni2+ shows complex electroreduction behaviors. The proposed process can serve as an alternative feasible route for multi metal recycling from WPCBs.
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Affiliation(s)
- Qinyi Xia
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Qingming Song
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China.
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6
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Liu K, Wang M, Tsang DCW, Liu L, Tan Q, Li J. Facile path for copper recovery from waste printed circuit boards via mechanochemical approach. J Hazard Mater 2022; 440:129638. [PMID: 35933860 DOI: 10.1016/j.jhazmat.2022.129638] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/13/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Recycling copper (Cu0) from waste printed circuit boards (PCBs) is a prevalent challenge. Here, we propose a new pathway and reveal mechanisms for recovering Cu0 from waste PCBs via a mechanochemical approach. The successful application of mechanical force avoids using inorganic acid in the Cu0 recovery process. Our work demonstrates that ferric chloride (FeCl3) was superior to ferric sulfate and ferric nitrate as a solid-phase reagent for Cu0 recovery due to chloride complexation. Under the induction of mechanical force, the Cu0 in the waste PCBs was oxidized by Fe3+ and complexed by Cl¯ to form a meta-stable cuprous chloride, which was susceptible to leaching in an acidic liquid-phase system constructed by hydrolysis of ferric salt. Further mechanism analysis reveals that in the mechanochemical solid-phase reaction, Cu0, metallic impurities, metal oxides, and carbon materials from waste PCBs could also reduce Fe3+ to Fe2+. The optimum conditions for Cu0 recovery from waste PCB powder with FeCl3 as a solid-phase reagent were: rotational speed of 500 rpm, Cu0:Fe3+ molar ratio of 1:20, and reaction time of 120 min, achieving the highest recovery of 99.6 wt%. This study presents a facile path for Cu0 recovery from waste PCBs for resource circulation.
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Affiliation(s)
- Kang Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Mengmeng Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; Research Centre for Environmental Technology and Management, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Lili Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Quanyin Tan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jinhui Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
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7
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Kouloumpis V, Yan X. Life cycle assessment of a novel metal recovery method from co-processing of coal mine waste and low-grade printed circuit boards. J Environ Manage 2022; 314:115074. [PMID: 35468433 DOI: 10.1016/j.jenvman.2022.115074] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 04/02/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
A double waste stream problem arises from the increasing use of electrical and electronic equipment and their energy consumption: potentially toxic wastes from the equipment itself and potential acid mine drainage from the waste of the coal mines that provide the fuel to cover the energy demand. CEReS (Co-processing of Coal Mine & Electronic Wastes: Novel Resources for a Sustainable Future) is a novel method to co-process the coal mine and low-grade PCBs waste to reduce their environmental impacts while producing metals and other valuable products. The aim of this study is to investigate whether CEReS method is more environmentally friendly than the conventional practices of landfilling and incineration. Based on a Polish coal mine case study, our study found that the CEReS method could potentially eliminate the environmental impacts related to toxicity but increase the climate change impacts by ten times. A sensitivity analysis has shown that using a lower carbon electricity mix could reduce the climate change and fossil depletion impacts. It is also recommended to reduce water and energy requirements in some stages of the method.
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Affiliation(s)
- Victor Kouloumpis
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Penryn, TR10 9FE, UK; Environment and Sustainability Institute, University of Exeter, Penryn, TR10 9FE, UK; School of Production Engineering and Management, Technical University of Crete, Chania, 73100, Greece.
| | - Xiaoyu Yan
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Penryn, TR10 9FE, UK; Environment and Sustainability Institute, University of Exeter, Penryn, TR10 9FE, UK
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8
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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. J Hazard Mater 2022; 430:128493. [PMID: 35739674 DOI: 10.1016/j.jhazmat.2022.128493] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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Jadhao PR, Pandey A, Pant KK, Nigam KDP. Efficient recovery of Cu and Ni from WPCB via alkali leaching approach. J Environ Manage 2021; 296:113154. [PMID: 34216905 DOI: 10.1016/j.jenvman.2021.113154] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/22/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The large generation of electronic waste (e-waste) is posing a serious threat to society. It is important to develop sustainable technology for the effective management of e-waste and the recovery of valuable metals from it. The present study employed hydrometallurgical approach for Cu and Ni extraction from waste printed circuit boards (WPCB) of mobile phones. This study demonstrates the application of ammonia-ammonium sulfate leaching for the maximum recovery of Cu and Ni. Investigations revealed that the most favourable reaction parameters for efficient metal extraction are - ammonia concentration - 90 g/L, ammonium sulfate concentration - 180 g/L, H2O2 concentration - 0.4 M, time - 4 h, liquid to solid ratio - 20 mL/g, temperature - 80 °C and agitation speed - 700 rpm. Under these conditions, 100% Cu and 90% Ni were extracted. Furthermore, the kinetic study was performed using the shrinking core model which revealed that the internal diffusion is the rate-controlling step for Cu and Ni extraction. The activation energies for Cu and Ni extraction were found out to be 4.5 and 5.7 kJ/mol, respectively. Finally, Cu was recovered with 98.38% purity using electrowinning at a constant DC voltage of 2.0 V at Al cathode. The present study provides a solution for concurrent extraction of Cu and Ni from the raw WPCB of mobile phones and selective recovery of Cu from metal leached solution. The process has the potential to recover the resources from WPCB while minimising the pollution caused by mismanagement of WPCB.
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Affiliation(s)
- Prashant Ram Jadhao
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Ashish Pandey
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - K K Pant
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India.
| | - K D P Nigam
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India
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Yu Y, Huang Q, Zhou J, Wu Z, Deng H, Liu X, Lin Z. One-step extraction of high-purity CuCl 2·2H 2O from copper-containing electroplating sludge based on the directional phase conversion. J Hazard Mater 2021; 413:125469. [PMID: 33930976 DOI: 10.1016/j.jhazmat.2021.125469] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
The recovery of heavy metals is a vital way to turn electroplating sludge into resources and reduce its environmental hazards. However, the complex compositions of the polymetallic electroplating sludge severely limit the selective recovery of metal resources such as copper. In this study, we took a kind of copper-containing electroplating sludge (C-ES) as an example present and investigated the process of copper extraction. The copper and other metals were directional converted through an accurate phase transformation process carried out by chlorination combined with thermal regulation. Eventually, the copper was selectively recovered in the form of CuCl2·2H2O, while the rest of the metals were converted into stable metal salts or oxides. The HCl solution was the best regulator for selective copper recovery. Under the optimal conditions, the recovery of copper approached 97% and the purity of the CuCl2·2H2O product was about 95%. The kinetic reaction equation of the CuCl2 volatilization process can be described by Power Low, G(α) = α1/15. The economic estimate based on experimentation indicates the profit of recycling CuCl2·2H2O is about $23.2/kg. This work provides a novel, simple, and efficient approach to the selective recovery of heavy metal from polymetallic solid wastes.
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Affiliation(s)
- Yao Yu
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510006, PR China
| | - Qiuyun Huang
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510006, PR China
| | - Jin Zhou
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510006, PR China
| | - Zhen Wu
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510006, PR China
| | - Hong Deng
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510006, PR China
| | - Xueming Liu
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510006, PR China.
| | - Zhang Lin
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, 510006, PR China; School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China
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11
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Kadivar S, Pourhossein F, Mousavi SM. Recovery of valuable metals from spent mobile phone printed circuit boards using biochar in indirect bioleaching. J Environ Manage 2021; 280:111642. [PMID: 33293166 DOI: 10.1016/j.jenvman.2020.111642] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/06/2020] [Accepted: 10/25/2020] [Indexed: 06/12/2023]
Abstract
Improving the bioleaching efficiency of metals from spent mobile phone printed circuit boards (PCBs) in a short time has been of major interest in recent years. In this paper, a novel cheap catalyst (oak wood biochar) was used to improve the copper and nickel bioleaching efficiency from spent mobile phone PCBs. The biochar was derived from oak wood through slow pyrolysis at a low temperature of 500 °C for 1h. The results of RSM optimization indicated that the optimum conditions to maximize copper and nickel recovery were 1.6 g/L biochar and 16 g/L pulp density. The findings indicated that compared to without the presence of biochar, the leach yields of copper and nickel were high. As much as 98% of copper and 82% of nickel were leached by indirect bioleaching under optimum conditions. The better performance in the presence of biochar is due to both galvanic interactions between biochar and solid waste. The biochemical characterization of bioleaching solution suggested that the high concentration of biochar (> 1.6 g/L) led to copper absorption by functional groups on the surface of biochar. Compared to chemical leaching, the bioleaching has better performance. Under optimum conditions, the copper and nickel recovery by indirect bioleaching was 36% and 64% more than that by chemical leaching. Also, it is found that biochar has a positive effect on the chemical leaching process. Therefore, in this paper, the function of biochar was elaborated not only in bio-hydrometallurgy but also in the hydrometallurgy process.
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Affiliation(s)
- Saeede Kadivar
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
| | - Fatemeh Pourhossein
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
| | - Seyyed Mohammad Mousavi
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
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12
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Zhou H, Liu G, Zhang L, Zhou C. Mineralogical and morphological factors affecting the separation of copper and arsenic in flash copper smelting slag flotation beneficiation process. J Hazard Mater 2021; 401:123293. [PMID: 32629353 DOI: 10.1016/j.jhazmat.2020.123293] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/19/2020] [Accepted: 06/20/2020] [Indexed: 06/11/2023]
Abstract
Separating copper and arsenic has always been a major problem in the copper slag flotation process, which influences copper slag utilization and the environmental safety. A comparative study of flash smelting furnace (FSF) slag and its flotation products (concentrate and tailing) reveals the factors affecting the separation of copper and arsenic in the beneficiation process from the perspective of mineralogy and morphology. The elemental fractionation in the process shows a positive correlation of As, Cu and Cd and an obvious correlation between speciation transformation of copper and arsenic was observed. The occurrence of arsenic and copper in FSF slag correlate the key phases of arsenic copper alloys, accounted for 88.91 % of total arsenic-bearing phases and 32.28% of copper-bearing phases. Closely-embeded matte and copper-arsenic alloys incerease the difficulty of the separation suggesting the finer grinding is needed for slag. Arsenic is liberated and oxidized into arsenate compounds while the recombination of As-O and Cu-S happened in the process affecting the selectivity of copper and arsenic. Arsenic fixed in silicate minerals is discharged into tailing which suggested to induce and fix arsenic into silicate minerals can facilitate arsenic removal from concentrate. FSF slag and its flotation concnetrate show risks of some of some of HMs which should be cautiously transported, disposed, and utilized.
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Affiliation(s)
- Huihui Zhou
- CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi'an, Shanxi 710075, China.
| | - Guijian Liu
- CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi'an, Shanxi 710075, China.
| | - Liqun Zhang
- School of Resource and Environmental Engineering, Anhui University, Hefei 230601, China
| | - Chuncai Zhou
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
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13
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Sibanda V, Sipunga E, Danha G, Mamvura TA. Enhancing the flotation recovery of copper minerals in smelter slags from Namibia prior to disposal. Heliyon 2019; 6:e03135. [PMID: 31909286 PMCID: PMC6940633 DOI: 10.1016/j.heliyon.2019.e03135] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/11/2019] [Accepted: 12/24/2019] [Indexed: 11/15/2022] Open
Abstract
Namibia Custom Smelters (NCS) process a range of copper concentrates in their three furnaces, namely; top submerged lance, copper converter and reverberatory furnaces, in order to produce mattes and fayalitic slags. The copper content of the slags range between 0.8 to 5 wt. % and this is considered too high for disposal to the environment. Currently, the slags are sent to a milling and flotation plant for liberation and recovery of residual copper. The copper recoveries realized in the plant are much lower than expected and it has been postulated that some copper minerals may be occurring in forms that are more difficult to float like oxides or fine disseminations in the gangue matrix. Mineralogical analysis of the slag samples was done using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. The analysis did not reveal the presence of copper oxide minerals, however most scans showed copper sulphide minerals as free grains and some finely disseminated in fayalite gangue. In the first phase of the present experimental studies, the slags were milled to 75% passing 45 microns, which is the degree of milling done in the existing plant mill-float circuit. A range of commercial flotation reagents that include xanthates, dithiophosphates, mercaptobenzothiazole, thionocarbamates, fatty acids, sulphides and sulphates were used in the flotation test-work. The copper recoveries obtained in the mill-float stage were between 70 - 80%. In the second phase of the study, the flotation tailings were further milled to 90% passing 45 microns and floated. The cumulative copper recoveries increased markedly to over 90%, which represents a significant improvement in comparison to the recoveries obtained from the mill-float process. Sodium alkyl dithiophosphate, mercaptobenzothiazole (FC7245) was found to be the secondary flotation reagent that gave the best copper recoveries.
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Affiliation(s)
- V Sibanda
- School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits, 2050, South Africa
| | - E Sipunga
- School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits, 2050, South Africa
| | - G Danha
- Department of Chemical, Materials and Metallurgical Engineering, Faculty of Engineering and Technology, Botswana International University of Science and Technology, Plot 10071, Boseja Ward, Private Bag 16, Palapye, Botswana
| | - T A Mamvura
- Department of Chemical, Materials and Metallurgical Engineering, Faculty of Engineering and Technology, Botswana International University of Science and Technology, Plot 10071, Boseja Ward, Private Bag 16, Palapye, Botswana
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14
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Kaur A, Boghani HC, Milner EM, Kimber RL, Michie IS, Daalmans R, Dinsdale RM, Guwy AJ, Head IM, Lloyd JR, Yu EH, Sadhukhan J, Premier GC. Bioelectrochemical treatment and recovery of copper from distillery waste effluents using power and voltage control strategies. J Hazard Mater 2019; 371:18-26. [PMID: 30844646 DOI: 10.1016/j.jhazmat.2019.02.100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/13/2019] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
Copper recovery from distillery effluent was studied in a scalable bioelectro-chemical system with approx. 6.8 L total volume. Two control strategies based on the control of power with maximum power point tracking (MPPT) and the application of 0.5 V using an external power supply were used to investigate the resultant modified electroplating characteristics. The reactor system was constructed from two electrically separated, but hydraulically connected cells, to which the MPPT and 0.5 V control strategies were applied. Three experiments were carried out using a relatively high copper concentration i.e. 1000 mg/L followed by a lower concentration i.e. 50 mg/L, with operational run times defined to meet the treatment requirements for distillery effluents considered. Real distillery waste was introduced into the cathode to reduce ionic copper concentrations. This waste was then recirculated to the anode as a feed stock after the copper depletion step, in order to test the bioenergy self-sustainability of the system. Approx. 60-95% copper was recovered in the form of deposits depending on starting concentration. However, the recovery was low when the anode was supplied with copper depleted distillery waste. Through process control (MPPT or 0.5 V applied voltage) the amount and form of the copper recovered could be manipulated.
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Affiliation(s)
- Amandeep Kaur
- Sustainable Environment Research Centre (SERC), University of South Wales, Pontypridd, CF37 1DL, UK.
| | - Hitesh C Boghani
- College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Edward M Milner
- Chemical Engineering and Advanced Materials, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Richard L Kimber
- School of Earth and Environmental Science, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Iain S Michie
- Sustainable Environment Research Centre (SERC), University of South Wales, Pontypridd, CF37 1DL, UK
| | | | - Richard M Dinsdale
- Sustainable Environment Research Centre (SERC), University of South Wales, Pontypridd, CF37 1DL, UK
| | - Alan J Guwy
- Sustainable Environment Research Centre (SERC), University of South Wales, Pontypridd, CF37 1DL, UK
| | - Ian M Head
- School of Earth and Environmental Science, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Jonathan R Lloyd
- Chemical Engineering and Advanced Materials, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Eileen H Yu
- College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jhuma Sadhukhan
- Centre for Environment & Sustainability, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Giuliano C Premier
- Sustainable Environment Research Centre (SERC), University of South Wales, Pontypridd, CF37 1DL, UK
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15
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Rozas EE, Mendes MA, Custódio MR, Espinosa DCR, do Nascimento CAO. Self-assembly of supramolecular structure based on copper-lipopeptides isolated from e-waste bioleaching liquor. J Hazard Mater 2019; 368:63-71. [PMID: 30665109 DOI: 10.1016/j.jhazmat.2019.01.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 01/12/2019] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
Supramolecular structures were produced by auto-assembling CuCN blocks derived from copper-lipopeptides (CuLps) isolated from bioleaching liquor. Lipopeptides produced by B. subtilis Hyhel1 have been previously related as responsible by bioleaching and intracellular copper crystal production. However, there were no records relating CuLps to extracellular copper crystal production. To study this process, CuLps were isolated from bioleaching liquor and kept at 8 °C to facilitate the CuLps aggregation. After three months, blue spheres (BS) were observed in the CuLp fraction. These spheres were then analyzed by SEM-EDS, MALDI-TOF-MS/MS, GC-MS and FTIR. SEM-EDS analysis showed that they were formed by polycrystalline structures mainly composed by Cu (46.5% m/m) and positioned concentrically. MALDI-TOF-MS/MS and GCMS showed that peptide bonds of CuLp were broken, producing lipid chains and amino acids free. The FTIR of BS showed three nitro groups: CN, NN and NO, which were not found in the control. These data suggest that the CuLp amino acid produced a CN group linked to copper, as CuCN blocks, that auto-assembled in supramolecular structures. This phenomenon could be explored as a method to recover copper and to obtain supramolecular CuCN structures, which in turn may be used as template for superconductor or computing devices.
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Affiliation(s)
- Enrique E Rozas
- Dempster-Poli-USP, Chemical Engineering Department, University of São Paulo (USP), Av. Prof. Lineu Prestes 580, block 21, CEP: 05508-910, São Paulo, Brazil.
| | - Maria Anita Mendes
- Dempster-Poli-USP, Chemical Engineering Department, University of São Paulo (USP), Av. Prof. Lineu Prestes 580, block 21, CEP: 05508-910, São Paulo, Brazil
| | - Marcio Reis Custódio
- Department of General Physiology, Institute of Biosciences, University of São Paulo, Rua do Matão, Travessa 14, 101, CEP: 05508-090, Brazil
| | - Denise C R Espinosa
- LAREX, Chemical Engineering Department, University of São Paulo, Av. Prof. Lineu Prestes 580, block 21, CEP: 05508-910, São Paulo (USP), Brazil
| | - Claudio A O do Nascimento
- Dempster-Poli-USP, Chemical Engineering Department, University of São Paulo (USP), Av. Prof. Lineu Prestes 580, block 21, CEP: 05508-910, São Paulo, Brazil
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16
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Ulman K, Ghose A, Maroufi S, Mansuri I, Sahajwalla V. Disentanglement of random access memory cards to regenerate copper foil: A novel thermo-electrical approach. Waste Manag 2018; 81:138-147. [PMID: 30527030 DOI: 10.1016/j.wasman.2018.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 09/20/2018] [Accepted: 10/01/2018] [Indexed: 06/09/2023]
Abstract
This paper reports the development of a novel process combining thermal and electrical treatments, which are optimised to provide efficient recovery of copper foil from Random Access Memory cards (RAMs). A primary thermal transformation at 900 °C facilitates a highly efficient recovery of copper foils from RAMs during the secondary processing in the electrical fragmenter, using only 10 pulses at 150 kV. The process yield was 98% and inductively coupled plasma (ICP) analysis showed that the copper foils had 98% purity. X-ray diffraction (XRD) confirmed the presence of copper in a crystalline face-centred cubic (FCC) form. Scanning electron microscopy (SEM) - energy dispersive spectroscopy (EDS) analysis of the foils assisted in understanding the underlying mechanism of electrical separation. Transmission electron microscopy (TEM) gave a new perspective on the regeneration of copper foils wherein new copper grains depicted a ribbon like growth pattern. The copper foils had an electrical conductivity similar to that of commercially available pure copper sheets. Thus, the mechanism of thermo-electrical transformation was studied in detail and regenerated copper foils of high electrical conductivity were afforded from end-of-life RAMs.
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Affiliation(s)
- Khushalini Ulman
- Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia.
| | - Anirban Ghose
- Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia.
| | - Samane Maroufi
- Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia.
| | - Irshad Mansuri
- Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia.
| | - Veena Sahajwalla
- Sustainable Materials Research and Technology Centre (SMaRT Centre), School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney 2052, Australia.
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17
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Zhang DJ, Dong L, Li YT, Wu Y, Ma YX, Yang B. Copper leaching from waste printed circuit boards using typical acidic ionic liquids recovery of e-wastes' surplus value. Waste Manag 2018; 78:191-197. [PMID: 32559904 DOI: 10.1016/j.wasman.2018.05.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/14/2018] [Accepted: 05/19/2018] [Indexed: 06/11/2023]
Abstract
In this study, using several types of acidic ionic liquids as the leaching reagents, the leaching behaviors of the copper present in waste printed circuit boards (WPCBs) were investigated. The effects of various parameters on the copper leaching rate were studied, such as the particle size of the shredded WPCB, type of ionic liquid used, hydrogen peroxide dosage, solid-to-liquid ratio, leaching temperature, and leaching time. The experimental results showed that the copper leaching rate increases continuously when the powder particle size is increased from 0.071 to 0.500 mm. Moreover, the copper leaching rate also increases with an increase in the leaching temperature. In contrast, the leaching rate first increases and then decreases with increases in the leaching time, hydrogen peroxide dosage, and solid-to-liquid ratio. The optimal conditions that provided a 98.31% copper leaching rate were: particle size >0.500 mm, 8.5 mL 90% (v/v) ionic liquid, 1.5 mL 30% hydrogen peroxide, solid-to-liquid ratio of 1/20, leaching temperature of 80 °C, and leaching time of 2 h.
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Affiliation(s)
- Ding-Jun Zhang
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Li Dong
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Yong-Tong Li
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Yanfei Wu
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Ying-Xia Ma
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Bin Yang
- State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
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18
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Silva WC, de Souza Corrêa R, da Silva CSM, Afonso JC, da Silva RS, Vianna CA, Mantovano JL. Recovery of base metals, silicon and fluoride ions from mobile phone printed circuit boards after leaching with hydrogen fluoride and hydrogen peroxide mixtures. Waste Manag 2018; 78:781-788. [PMID: 32559970 DOI: 10.1016/j.wasman.2018.06.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 05/21/2018] [Accepted: 06/25/2018] [Indexed: 06/11/2023]
Abstract
The recovery of copper, nickel, zinc, silicon, iron, aluminum, tin and fluoride ions from fluoride leach liquors of non-ground printed circuit boards (PCBs) from mobile phones is described in detail. These PCBs were leached with HF + H2O2 mixtures after previous treatment with 6 mol L-1 NaOH (removal of the solder mask). A combination of solvent extraction (SX) and precipitation techniques was used. 99.5 wt% zinc, copper and nickel, in this order, were extracted in one stage (Zn, Ni) or two stages (Cu) with di-2-ethylhexylphosphoric acid (D2EHPA) diluted in kerosene (25 °C, A/O = 1 v/v) after adjusting the pH of the leachate. They were easily stripped by aqueous H2SO4. Iron, aluminum and tin did not interfere because they were masked by fluoride ions. Iron and aluminum were precipitated together as Na3FeF6 + Na3AlF6 by careful addition of aqueous NaOH. Silicon, tin and fluoride ions were recovered together (Na2SiF6 + Na2SnF6 + NaF) by careful evaporation of the aqueous solution after SX of nickel. The tin salt was leached from this solid by absolute ethanol. High HF concentration (10 mol L-1) in the leachant affected SX of Cu(II) and precipitation of iron/aluminum flurocomplexes since some NaF partially precipitated at acidic pH.
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Affiliation(s)
- Walner Costa Silva
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Roger de Souza Corrêa
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Calvin Sampaio Moreira da Silva
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Júlio Carlos Afonso
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil.
| | - Rubens Souza da Silva
- Chemistry and Nuclear Materials Department, Institute of Nuclear Engineering, Rua Hélio de Almeida, 75, 21941-906 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Cláudio Augusto Vianna
- Chemistry and Nuclear Materials Department, Institute of Nuclear Engineering, Rua Hélio de Almeida, 75, 21941-906 Ilha do Fundão, Rio de Janeiro, Brazil
| | - José Luiz Mantovano
- Chemistry and Nuclear Materials Department, Institute of Nuclear Engineering, Rua Hélio de Almeida, 75, 21941-906 Ilha do Fundão, Rio de Janeiro, Brazil
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19
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Kazemi MJ, Kargar M, Nowroozi J, Akhavan Sepahi A, Doosti A, Manafi Z. The wide distribution of an extremely thermoacidophilic microorganism in the copper mine at ambient temperature and under acidic condition and its significance in bioleaching of a chalcopyrite concentrate. Rev Argent Microbiol 2018; 51:56-65. [PMID: 29954620 DOI: 10.1016/j.ram.2017.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 09/12/2017] [Accepted: 09/25/2017] [Indexed: 10/28/2022] Open
Abstract
Thermoacidophiles can exist in a state of dormancy both in moderate temperatures and even in cold conditions in heap leaching. Sulphide mineral ores such as chalcopyrite produce sulfuric acid when exposed to the air and water. The produced sulfuric acid leads to the decrease of pH and exothermic reactions in heap leaching causing the temperature to increase up to 55°C and the activation of thermoacidophilic microorganisms. The aim of the present study was to isolate indigenous extreme thermoacidophilic microorganisms at ambient temperature from Sarcheshmeh Copper Complex, to adapt them to the high pulp density of a chalcopyrite concentrate, and to determine their efficiency in chalcopyrite bioleaching in order to recover copper. In this study samples were collected at ambient temperature from Sarcheshmeh Copper Complex in Iran. Mixed samples were inoculated into the culture medium for enrichment of the microorganisms. Pure cultures from these enrichments were obtained by subculture of liquid culture to solid media. Morphological observation was performed under the scanning electron microscope. Isolates were adapted to 30% (w/v) pulp density. For the bioleaching test, the experiments were designed with DX7 software. Bioleaching experiments were carried out in Erlenmeyer flasks and a stirred tank reactor. The highest copper recovery in Erlenmeyer flasks was 39.46% with pulp 15%, inoculums 20%, size particle 90μm and 160rpm. The lowest recovery was 3.81% with pulp 20%, inoculums 20%, size particle 40μm and 140rpm after 28 days. In the reactor, copper recovery was 32.38%. Bioleaching residues were analyzed by the X-ray diffraction (XRD) method. The results showed no jarosite (KFe3(SO4)2(OH)6) had formed in the bioleaching experiments. It seems that the antagonistic reactions among various species and a great number of planktonic cells in Erlenmeyer flasks and the stirred tank reactor are the reasons for the low recovery of copper in our study.
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Affiliation(s)
- Mohammad Javad Kazemi
- Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, Iran
| | - Mohammad Kargar
- Department of Microbiology, Jahrom Branch, Islamic Azad University, Jahrom, Iran.
| | - Jamileh Nowroozi
- Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, Iran
| | - Abbas Akhavan Sepahi
- Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, Iran
| | - Abbas Doosti
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Zahra Manafi
- National Iranian Copper Industries Co., Sarcheshmeh Mine, Iran
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Han B, Altansukh B, Haga K, Stevanović Z, Jonović R, Avramović L, Urosević D, Takasaki Y, Masuda N, Ishiyama D, Shibayama A. Development of copper recovery process from flotation tailings by a combined method of high‒pressure leaching‒solvent extraction. J Hazard Mater 2018; 352:192-203. [PMID: 29609151 DOI: 10.1016/j.jhazmat.2018.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 03/07/2018] [Accepted: 03/08/2018] [Indexed: 06/08/2023]
Abstract
Sulfide copper mineral, typically Chalcopyrite (CuFeS2), is one of the most common minerals for producing metallic copper via the pyrometallurgical process. Generally, flotation tailings are produced as a byproduct of flotation and still consist of un‒recovered copper. In addition, it is expected that more tailings will be produced in the coming years due to the increased exploration of low‒grade copper ores. Therefore, this research aims to develop a copper recovery process from flotation tailings using high‒pressure leaching (HPL) followed by solvent extraction. Over 94.4% copper was dissolved from the sample (CuFeS2 as main copper mineral) by HPL in a H2O media in the presence of pyrite, whereas the iron was co‒dissolved with copper according to an equation given as CCu = 38.40 × CFe. To avoid co‒dissolved iron giving a negative effect on the subsequent process of electrowinning, solvent extraction was conducted on the pregnant leach solution for improving copper concentration. The result showed that 91.3% copper was recovered in a stripped solution and 98.6% iron was removed under the optimal extraction conditions. As a result, 86.2% of copper was recovered from the concentrate of flotation tailings by a proposed HPL‒solvent extraction process.
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Affiliation(s)
- Baisui Han
- Graduate School of Engineering and Resource Science, Akita University, 1‒1 Tegata Gakuen‒machi, Akita, 010‒8502, Japan.
| | - Batnasan Altansukh
- Graduate School of International Resource Sciences, Akita University, 1‒1 Tegata Gakuen‒machi, Akita, 010‒8502, Japan
| | - Kazutoshi Haga
- Graduate School of Engineering Science, Akita University, 1‒1 Tegata Gakuen‒machi Akita 010‒8502, Japan.
| | - Zoran Stevanović
- Mining and Metallurgy Institute Bor, Zeleni Bulevar 35, 19210, Bor, Serbia.
| | - Radojka Jonović
- Mining and Metallurgy Institute Bor, Zeleni Bulevar 35, 19210, Bor, Serbia
| | - Ljiljana Avramović
- Mining and Metallurgy Institute Bor, Zeleni Bulevar 35, 19210, Bor, Serbia
| | - Daniela Urosević
- Mining and Metallurgy Institute Bor, Zeleni Bulevar 35, 19210, Bor, Serbia
| | - Yasushi Takasaki
- Graduate School of International Resource Sciences, Akita University, 1‒1 Tegata Gakuen‒machi, Akita, 010‒8502, Japan
| | - Nobuyuki Masuda
- Graduate School of International Resource Sciences, Akita University, 1‒1 Tegata Gakuen‒machi, Akita, 010‒8502, Japan
| | - Daizo Ishiyama
- Graduate School of International Resource Sciences, Akita University, 1‒1 Tegata Gakuen‒machi, Akita, 010‒8502, Japan
| | - Atsushi Shibayama
- Graduate School of International Resource Sciences, Akita University, 1‒1 Tegata Gakuen‒machi, Akita, 010‒8502, Japan.
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21
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Cayumil R, Ikram-Ul-Haq M, Khanna R, Saini R, Mukherjee PS, Mishra BK, Sahajwalla V. High temperature investigations on optimising the recovery of copper from waste printed circuit boards. Waste Manag 2018; 73:556-565. [PMID: 28089398 DOI: 10.1016/j.wasman.2017.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 01/02/2017] [Accepted: 01/02/2017] [Indexed: 05/22/2023]
Abstract
High temperature pyrolysis investigations were carried out on waste printed circuit boards (PCBs) in the temperature range 800-1000°C under inert conditions, with an aim to determine optimal operating conditions for the recovery of copper. Pyrolysis residues were characterized using ICP-OES analysis, SEM/EDS and XRD investigations. Copper foils were successfully recovered after pyrolysis at 800°C for 10-20 min; the levels of Pb and Sn present were found to be quite low and these were generally present near the foil edges. The relative proportions of Pb and Sn became progressively higher at longer heating times due to enhanced diffusion of these molten metals in solid copper. While a similar behaviour was observed at 900°C, the pyrolysis at 1000°C resulted in copper forming Cu-Sn-Pb alloys; copper foils could no longer be recovered. Optimal conditions were identified for the direct recovery of copper from waste PCBs with minimal processing. This approach is expected to make significant contributions towards enhancing material recovery, process efficiency and the environmental sustainability of recycling e-waste. Pyrolysis at lower temperatures, short heating times, coupled with reductions in process steps are expected to significantly reduce energy consumption and pollution associated with the handling and processing of waste PCBs.
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Affiliation(s)
- R Cayumil
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - M Ikram-Ul-Haq
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - R Khanna
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
| | - R Saini
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - P S Mukherjee
- CSIR - Institute of Minerals and Material Technology, Advanced Materials Technology Department, Bhubaneshwar, Orissa 751013, India
| | - B K Mishra
- CSIR - Institute of Minerals and Material Technology, Advanced Materials Technology Department, Bhubaneshwar, Orissa 751013, India
| | - V Sahajwalla
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Sun ZHI, Xiao Y, Sietsma J, Agterhuis H, Yang Y. Complex electronic waste treatment - An effective process to selectively recover copper with solutions containing different ammonium salts. Waste Manag 2016; 57:140-148. [PMID: 27021695 DOI: 10.1016/j.wasman.2016.03.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 06/05/2023]
Abstract
Recovery of valuable metals from electronic waste has been highlighted by the EU directives. The difficulties for recycling are induced by the high complexity of such waste. In this research, copper could be selectively recovered using an ammonia-based process, from industrially processed information and communication technology (ICT) waste with high complexity. A detailed understanding on the role of ammonium salt was focused during both stages of leaching copper into a solution and the subsequent step for copper recovery from the solution. By comparing the reactivity of the leaching solution with different ammonium salts, their physiochemical behaviour as well as the leaching efficiency could be identified. The copper recovery rate could reach 95% with ammonium carbonate as the leaching salt. In the stage of copper recovery from the solution, electrodeposition was introduced without an additional solvent extraction step and the electrochemical behaviour of the solution was figured out. With a careful control of the electrodeposition conditions, the current efficiency could be improved to be 80-90% depending on the ammonia salts and high purity copper (99.9wt.%). This research provides basis for improving the recyclability and efficiency of copper recovery from such electronic waste and the whole process design for copper recycling.
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Affiliation(s)
- Z H I Sun
- Department of Materials Science and Engineering, TU Delft, 2628 CD Delft, The Netherlands; National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
| | - Y Xiao
- Ironmaking Department, R&D, Tata Steel, 1970 CA IJmuiden, The Netherlands
| | - J Sietsma
- Department of Materials Science and Engineering, TU Delft, 2628 CD Delft, The Netherlands
| | - H Agterhuis
- Business Development, Van Gansewinkel Groep BV, 5657 DH Eindhoven, The Netherlands
| | - Y Yang
- Department of Materials Science and Engineering, TU Delft, 2628 CD Delft, The Netherlands
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Fogarasi S, Imre-Lucaci F, Egedy A, Imre-Lucaci Á, Ilea P. Eco-friendly copper recovery process from waste printed circuit boards using Fe³⁺/Fe²⁺ redox system. Waste Manag 2015; 40:136-43. [PMID: 25816768 DOI: 10.1016/j.wasman.2015.02.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/17/2015] [Accepted: 02/22/2015] [Indexed: 05/22/2023]
Abstract
The present study aimed at developing an original and environmentally friendly process for the recovery of copper from waste printed circuit boards (WPCBs) by chemical dissolution with Fe(3+) combined with the simultaneous electrowinning of copper and oxidant regeneration. The recovery of copper was achieved in an original set-up consisting of a three chamber electrochemical reactor (ER) connected in series with a chemical reactor (CR) equipped with a perforated rotating drum. Several experiments were performed in order to identify the optimal flow rate for the dissolution of copper in the CR and to ensure the lowest energy consumption for copper electrodeposition in the ER. The optimal hydrodynamic conditions were provided at 400 mL/min, leading to the 75% dissolution of metals and to a low specific energy consumption of 1.59 kW h/kg Cu for the electrodeposition process. In most experiments, the copper content of the obtained cathodic deposits was over 99.9%.
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Affiliation(s)
- Szabolcs Fogarasi
- Babeş-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, Cluj-Napoca RO-400028, Romania
| | - Florica Imre-Lucaci
- Babeş-Bolyai University, Interdisciplinary Research Institute on Bio-Nano-Sciences, 42 Treboniu Laurian Street, Cluj-Napoca RO-400271, Romania
| | - Attila Egedy
- University of Pannonia, Department of Process Engineering, Egyetem Str. 10, H-8200 Veszprém, Hungary
| | - Árpád Imre-Lucaci
- Babeş-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, Cluj-Napoca RO-400028, Romania.
| | - Petru Ilea
- Babeş-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, Cluj-Napoca RO-400028, Romania
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Cayumil R, Khanna R, Ikram-Ul-Haq M, Rajarao R, Hill A, Sahajwalla V. Generation of copper rich metallic phases from waste printed circuit boards. Waste Manag 2014; 34:1783-92. [PMID: 25052340 DOI: 10.1016/j.wasman.2014.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 04/10/2014] [Accepted: 05/06/2014] [Indexed: 05/11/2023]
Abstract
The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containing significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150°C under argon gas flowing at 1L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the metallic phase. The heat treatment temperature was chosen to be above the melting point of copper; molten copper helped to concentrate metallic constituents and their separation from the carbonaceous residue and the slag. Inert atmosphere prevented the re-oxidation of metals and the loss of carbon in the gaseous fraction. Recycling e-waste is expected to lead to enhanced metal recovery, conserving natural resources and providing an environmentally sustainable solution to the management of waste products.
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Affiliation(s)
- R Cayumil
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - R Khanna
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
| | - M Ikram-Ul-Haq
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - R Rajarao
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - A Hill
- CSIRO Process Science & Engineering, Clayton, Melbourne, VIC 3168, Australia
| | - V Sahajwalla
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Huang J, Chen M, Chen H, Chen S, Sun Q. Leaching behavior of copper from waste printed circuit boards with Brønsted acidic ionic liquid. Waste Manag 2014; 34:483-488. [PMID: 24246577 DOI: 10.1016/j.wasman.2013.10.027] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 09/16/2013] [Accepted: 10/15/2013] [Indexed: 06/02/2023]
Abstract
In this work, a Brønsted acidic ionic liquid, 1-butyl-3-methyl-imidazolium hydrogen sulfate ([bmim]HSO4), was used to leach copper from waste printed circuit boards (WPCBs, mounted with electronic components) for the first time, and the leaching behavior of copper was discussed in detail. The results showed that after the pre-treatment, the metal distributions were different with the particle size: Cu, Zn and Al increased with the increasing particle size; while Ni, Sn and Pb were in the contrary. And the particle size has significant influence on copper leaching rate. Copper leaching rate was higher than 99%, almost 100%, when 1g WPCBs powder was leached under the optimum conditions: particle size of 0.1-0.25 mm, 25 mL 80% (v/v) ionic liquid, 10 mL 30% hydrogen peroxide, solid/liquid ratio of 1/25, 70°C and 2h. Copper leaching by [bmim]HSO4 can be modeled with the shrinking core model, controlled by diffusion through a solid product layer, and the kinetic apparent activation energy has been calculated to be 25.36 kJ/mol.
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Affiliation(s)
- Jinxiu Huang
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
| | - Mengjun Chen
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China.
| | - Haiyan Chen
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
| | - Shu Chen
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
| | - Quan Sun
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
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Oleszek S, Grabda M, Shibata E, Nakamura T. Distribution of copper, silver and gold during thermal treatment with brominated flame retardants. Waste Manag 2013; 33:1835-1842. [PMID: 23746984 DOI: 10.1016/j.wasman.2013.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 05/07/2013] [Accepted: 05/07/2013] [Indexed: 06/02/2023]
Abstract
The growing consumption of electric and electronic equipment results in creating an increasing amount of electronic waste. The most economically and environmentally advantageous methods for the treatment and recycling of waste electric and electronic equipment (WEEE) are the thermal techniques such as direct combustion, co-combustion with plastic wastes, pyrolysis and gasification. Nowadays, this kind of waste is mainly thermally treated in incinerators (e.g. rotary kilns) to decompose the plastics present, and to concentrate metals in bottom ash. The concentrated metals (e.g. copper, precious metals) can be supplied as a secondary raw material to metal smelters, while the pyrolysis of plastics allows the recovery of fuel gases, volatilising agents and, eventually, energy. Indeed, WEEE, such as a printed circuit boards (PCBs) usually contains brominated flame retardants (BFRs). From these materials, hydrobromic acid (HBr) is formed as a product of their thermal decomposition. In the present work, the bromination was studied of copper, silver and gold by HBr, originating from BFRs, such as Tetrabromobisphenol A (TBBPA) and Tetrabromobisphenol A-Tetrabromobisophenol A diglycidyl ether (TTDE) polymer; possible volatilization of the bromides formed was monitored using a thermo-gravimetric analyzer (TGA) and a laboratory-scale furnace for treating samples of metals and BFRs under an inert atmosphere and at a wide range of temperatures. The results obtained indicate that up to about 50% of copper and silver can evolve from sample residues in the form of volatile CuBr and AgBr above 600 and 1000°C, respectively. The reactions occur in the molten resin phase simultaneously with the decomposition of the brominated resin. Gold is resistant to HBr and remains unchanged in the residue.
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Affiliation(s)
- Sylwia Oleszek
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577, Japan.
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