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P Sivakumar, D Prabhakaran, M Thirumarimurugan
The aim of the study was to recover copper and lead metal from waste printed circuit boards (PCBs). The electrowinning method is found to be an effective recycling process to recover copper and lead metal from printed circuit board wastes. In order to simplify the process with affordable equipment, a simple ammonical leaching operation method was adopted. The selected PCBs were incinerated into fine ash powder at 500°C for 1 hour in the pyrolysis reactor. Then, the fine ash powder was subjected to acid-leaching process to recover the metals with varying conditions like acid-base concentration, electrode combination, and leaching time...
2018: Bioinorganic Chemistry and Applications
Tai Gyun Kim, Rajiv R Srivastava, Minji Jun, Min-Seuk Kim, Jae-Chun Lee
The ammoniacal leaching of surface-coated metals from automobile-discarded ABS plastics followed by their recovery through solvent extraction has been investigated. The leaching of ABS (typically containing 4.1% Cu, 1.3% Ni, and 0.03% Cr) could efficiently dissolve the ammine complexes of Cu and Ni, leaving Cr unleached as fine particles. The optimization studies for achieving the maximum efficiency revealed that the leaching of metal ions in different ammoniacal solutions follows the order CO3 2-  > Cl-  > SO4 2- ...
October 2018: Waste Management
Baisui Han, Batnasan Altansukh, Kazutoshi Haga, Zoran Stevanović, Radojka Jonović, Ljiljana Avramović, Daniela Urosević, Yasushi Takasaki, Nobuyuki Masuda, Daizo Ishiyama, Atsushi Shibayama
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...
June 15, 2018: Journal of Hazardous Materials
Peng Xing, Baozhong Ma, Chengyan Wang, Ling Wang, Yongqiang Chen
Continuous growth of the shipping industry and infrastructure has consumed large amounts of zinc-rich paint (ZP) for the protection of steel structures against corrosion. Consequently, a growing amount of waste zinc-rich paint residue (ZPR) is being generated from anticorrosion spraying. ZPR is classified as hazardous waste in most industrialized countries, but it contains considerable amounts of organic compounds with high calorific value and zinc species that can potentially be recycled. Most of the ZPR generated is not properly treated, and this study presents a simple and efficient process for recycling ZPR...
June 2018: Waste Management
Monica M Young, Cornelius J Van Der Merwe, Stefan J L Linde, Johan L Du Plessis
This study aimed to analyze historical soluble nickel exposure data from a South African base metal refinery and to identify trends in the soluble nickel exposure from 1981 until 2014 in the electrowinning department. Exposure data were presented in an exposure matrix, which described exposure profiles for both area and personal exposures inside two tankhouses. Exposure data were standardized by converting total nickel aerosol concentrations to inhalable nickel concentrations (correction factor 3.0). One-way analyses of variances (ANOVA) were conducted to identify significant differences in log-transformed area and personal exposures from 1982 until 2014, and the trends were assessed with linear regression...
March 2018: Journal of Occupational and Environmental Hygiene
Ninett Frenzel, Jennifer Hartley, Gero Frisch
Ionic liquids and deep eutectic solvents have great potential in metallurgical applications as specialised solvents. In order to design ionometallurgical electrowinning and electrorefining processes, it is essential to characterise the electrochemical behaviour of metal complexes and compare potentials between relevant solvents. For such investigations, a universal reference redox couple would be desirable. In this study we investigate the speciation and electrochemical behaviour of ferrocenium/ferrocene and hexacyanoferrate(iii/ii) as possible reference couples for 15 different ionic media on platinum (Pt), glassy carbon (GC) and gold (Au) working electrodes...
November 1, 2017: Physical Chemistry Chemical Physics: PCCP
S Abid Charef, A M Affoune, A Caballero, M Cruz-Yusta, J Morales
A parallel study of acidic and alkaline leaching for the recovery of Mn and Zn from spent alkaline batteries is outlined. Using H2SO4 as solvent and selecting appropriate conditions of temperature and concentration, all residues were dissolved except carbon. The separation and recovery of the two components were performed by electrodeposition with satisfactory results at pH values above 4 (current efficiency above 70% for Zn and Mn) but rather lower efficiencies as the pH decreased. Most of the Zn was selectively dissolved by alkaline leaching using a 6...
June 29, 2017: Waste Management
Tianzu Yang, Pengchun Zhu, Weifeng Liu, Lin Chen, Duchao Zhang
To avoid the adverse effects of tin on the smelting process used to recover copper from metal powders of waste printed circuit boards, an effective process is proposed that selectively extracts tin and its associated metals. That impacts of alkaline pressure oxidation leaching parameters on metal conversion were systematically investigated. The results showed that Sn, Pb, Al and small amounts of Zn in the metal powders were leached out, leaving copper residue. By optimizing the conditions, leaching recovery of 98...
June 19, 2017: Waste Management
Robinson Torres, Gretchen T Lapidus
An integral closed circuit hydrometallurgical process is presented for base metal recovery from electronic waste. The leaching medium consists of a sodium citrate solution, from which base metals are retrieved by direct electrowinning, and the barren solution is recycled back to the leaching stage. This leaching-electrowinning cycle was repeated four times. The redox properties of the fresh citrate solution, as well as the leach liquors, were characterized by cyclic voltammetry to determine adequate conditions for metal reduction, as well as to limit citrate degradation...
February 2017: Waste Management
J T S Irvine
Liquid salts comprising molten salts and ionic liquids offer important media to address both energy and materials challenges. Here we review topics presented in this Faraday Discussion volume related to improved electrowinning of metals, optimisation of processes, new electrochemical device concepts, chemistry in ionic liquids, conversion of biomass, carbon chemistry and nuclear applications. The underlying phenomenology is then reviewed and commentary given. Some future applications are then discussed, further exemplifying the high potential rewards achievable from these chemistries...
August 15, 2016: Faraday Discussions
Graeme A Snook, Katherine McGregor, Andrew J Urban, Marshall R Lanyon, R Donelson, Mark I Pownceby
The direct electrochemical reduction of solid titanium dioxide in a chloride melt is an attractive method for the production of titanium metal. It has been estimated that this type of electrolytic approach may reduce the costs of producing titanium sponge by more than half, with the additional benefit of a smaller environmental footprint. The process utilises a consumable carbon anode which releases a mixture of CO2 and CO gas during electrolysis, but suffers from low current efficiency due to the occurrence of parasitic side reactions involving carbon...
August 15, 2016: Faraday Discussions
Chuh-Shun Chen, Yu-Jen Shih, Yao-Hui Huang
Fly ash that was enriched with lead (Pb), formed as an intermediate in waste lead-acid battery (WLAB) smelting, was recycled by the hydro-electrometallurgy. Characterization of fly ash thereof indicated that the Pb was in the forms of PbSO4 (anglesite) and Pb2OSO4 (lanarkite). Nitric acid and sodium hydroxide were firstly used to study the leaching of the fly ash sample, which was affected by leachant dosage and solid-to-liquid ratio (S/L). At an S/L of 60gL(-1), the leachability of Pb was 43% and 67% in 2M acidic and basic solutions, respectively, based on an average 70wt% of Pb in the original fly ash...
June 2016: Waste Management
Cihan Ozgur, Sezen Coskun, Ata Akcil, Mehmet Beyhan, Ismail Serkan Üncü, Gokhan Civelekoglu
In this paper, oxidative leaching and electrowinnig processes were performed to recovery of mercury from spent tubular fluorescent lamps. Hypochlorite was found to be effectively used for the leaching of mercury to the solution. Mercury could be leached with an efficiency of 96% using 0.5M/0.2M NaOCl/NaCl reagents at 50°C and pH 7.5 for 2-h. Electrowinning process was conducted on the filtered leaching solutions and over the 81% of mercury was recovered at the graphite electrode using citric acid as a reducing agent...
November 2016: Waste Management
Daniel A Bertuol, Caroline M Machado, Mariana L Silva, Camila O Calgaro, Guilherme L Dotto, Eduardo H Tanabe
Continuing technological development decreases the useful lifetime of electronic equipment, resulting in the generation of waste and the need for new and more efficient recycling processes. The objective of this work is to study the effectiveness of supercritical fluids for the leaching of cobalt contained in lithium-ion batteries (LIBs). For comparative purposes, leaching tests are performed with supercritical CO2 and co-solvents, as well as under conventional conditions. In both cases, sulfuric acid and H2O2 are used as reagents...
May 2016: Waste Management
Ja-Kyung Koo, Heung-Ki Hong, Jae-Ho Lee
The consumption of rare metals from the industrial development has been increasing despite of unstable and limited rare metals supply. Copper electrolyte after copper electrorefining contains 200-300 mg/L of bismuth (Bi) and antimony (Sb). Bi and Sb were recovered through electrowinning of electrochemical method. After being concentrated using an ion exchange resin method, Bi was eluted by concentrated sulfuric acid and sodium chloride solution. And then Bi deficient resin was reeluted by hydrochloric acid to elute Sb...
November 2015: Journal of Nanoscience and Nanotechnology
Yang Jian-Guang, Lei Jie, Peng Si-Yao, Lv Yuan-Lu, Shi Wei-Qiang
The current research investigated a process combining leaching, purification and membrane electrodeposition to recover tin from the metal components of WPCBs. Experimental results showed that with a solid liquid ratio of 1:4, applying 1.1 times of stoichiometric SnCl4 dosage and HCl concentration of 3.5-4.0 mol/L at a temperature of 60-90°C, 99% of tin can be leached from the metal components of WPCBs. The suitable purification conditions were obtained in the temperature range of 30-45°C with the addition of 1...
March 5, 2016: Journal of Hazardous Materials
Angela C Kasper, Jordi Carrillo Abad, Montserrat García Gabaldón, Hugo M Veit, Valentín Pérez Herranz
The use of electrochemical techniques in the selective recovery of gold from a solution containing thiosulphate, ammonia, and copper, obtained from the leaching of printed circuit boards from mobile phones using ammoniacal thiosulphate, are shown in this work. First, cyclic voltammetry tests were performed to determine the potential of electrodeposition of gold and copper, and then, electrowinning tests at different potentials for checking the rates of recovery of these metals were performed. The results of the cyclic voltammetry show that copper deposition occurs at potentials more negative than -600 mV (Ag/AgCl), whereas the gold deposition can be performed at potentials more positives than -600 mV (Ag/AgCl)...
January 2016: Waste Management & Research
Anna M K Gustafsson, Fredrik Björefors, Britt-Marie Steenari, Christian Ekberg
Recycling of the semiconductor material copper indium gallium diselenide (CIGS) is important to ensure a future supply of indium and gallium, which are relatively rare and therefore expensive elements. As a continuation of our previous work, where we recycled high purity selenium from CIGS waste materials, we now show that copper and indium can be recycled by electrodeposition from hydrochloric acid solutions of dissolved selenium-depleted material. Suitable potentials for the reduction of copper and indium were determined to be -0...
2015: TheScientificWorldJournal
Marie Clancy, Mark J Styles, Colleen J Bettles, Nick Birbilis, Miao Chen, Yansheng Zhang, Qinfen Gu, Justin A Kimpton, Nathan A S Webster
Figures 7 and 8 of the article by Clancy et al. [(2015), J. Synchrotron Rad. 22, 366-375] are corrected.
May 2015: Journal of Synchrotron Radiation
Szabolcs Fogarasi, Florica Imre-Lucaci, Attila Egedy, Árpád Imre-Lucaci, Petru Ilea
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...
June 2015: Waste Management
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