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leaching pcbs with cyanide

Bioleaching of gold and copper from waste mobile

2011-9-1  Chromobacterium violaceum (C. violaceum), a cyanide generating bacterium has been used to leach out gold and copper from the waste mobile phone printed circuit boards (PCBs) containing ∼34.5% Cu and 0.025% Au in YP (yeast extract and polypeptone with glycine) medium.

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Evaluation of gold and silver leaching from printed ...

2014-2-1  The most common leaching agents that are being studied for the recovery of precious metals from PCB of mobile phones are cyanide, thiourea, halide, and thiosulfate (Jeffrey et al., 2003; Groenewald, 1977, Baláz et al., 1996, Lee et al., 2010). These solutions are submitted to a separation of solid/liquid and a purification process, such as impurities precipitation, solvent extraction, adsorption,

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(PDF) Bacterial Cyanide Generation in the Presence of ...

Bacterial Cyanide Generation in the Presence of Metal Ions (Na^+, Mg^ , Fe^ , Pb^ ) and Gold Bioleaching from Waste PCBs. Journal of Chemical Engineering of Japan, 2012. Huynh Hai. Kyoungkeun Yoo. Huynh Hai. Kyoungkeun Yoo. Download PDF. Download Full PDF Package. This paper.

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An Alkaline Glycine-Based Leach Process of Base and ...

2019-8-9  An exploratory research study on a new leaching system for the metallic portion of PCBs powder has been conducted and a comparison between conventional cyanidation, ammonia and direct glycine–cyanide leaching has been made. PCBs powder containing a high percentage of metals was used to evaluate the leachability of different metals in alkaline glycine solutions.

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(PDF) Gold recovery from printed circuit boards of

The cyanide-based solution was able to extract 88% of the gold, while sodium and ammonium thiosulfate extracted 70 and 75% of the gold, respectively. The

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Bioleaching of gold from waste printed circuit boards

2014-6-20  All the promoting effect can also be seen from the total cyanide amount generated, which corresponds to the optimum leaching efficiency. The combination of oxygen supplement, nutrients addition and the pretreatment by biooxidation made the gold bioleaching efficiency reach 70.6 %, which was higher than the previous reports.

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Leaching of gold and copper minerals in cyanide

The concept of leaching copper–gold ores using leach solutions which contain Cu (CN)32− was investigated. Gold leaching occurs in air saturated Cu (CN)32− solutions at a much slower rate than in...

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Electrochemical influence of quartz on cyanide

2020-1-1  Cyanide leaching is a conventional method for processing gold ore at home and abroad. Due to its advantages of maturity, low-cost and high-leaching rate, it always occupies an absolute dominance in gold extraction . Around the world, 80% of gold is recovered by cyanide leaching method . Moreover, for a long time, the cyanidation gold leaching process will still dominate the gold production.

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The environmental impact assessment of gold

2021-4-10  The comparative study on aqua regia and cyanide leaching methods pointed out that 6–8% of the commercial cyanide-based leaching agent potentially extracted gold at approximately 60% (25 °C) compared with the aqua regia extraction at 60 °C and 80 °C, when printed circuit boards of mobile phones were used as a sample .

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Gold Recovery from PCBs with Thiosulfate as

Request PDF Gold Recovery from PCBs with Thiosulfate as Complexing Agent Waste of electrical and electronic equipment (WEEE) is the fastest growing advanced type of solid waste streams in the ...

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An Alkaline Glycine-Based Leach Process of Base and ...

2019-8-9  An exploratory research study on a new leaching system for the metallic portion of PCBs powder has been conducted and a comparison between conventional cyanidation, ammonia and direct glycine–cyanide leaching has been made. PCBs powder containing a high percentage of metals was used to evaluate the leachability of different metals in alkaline ...

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[PDF] Current Status on Leaching Precious Metals

Abstract Current research on leaching precious metals from waste printed circuit boards (PCBs) in the world is introduced. In the paper, hydrometallurgical processing techniques including cyanide leaching, thiourea leaching, thiosulfate leaching, and halide leaching of precious metals are addressed in detail. In order to develop an environmentally friendly technique for recovery of precious ...

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(PDF) Bioleaching of gold and copper from waste

As metal leaching with a cyanogenic bacteria is inhibited (Kita et al., 2008) with the consumption of dissolved oxygen (DO) for bacterial respiration during the growth phase, this research is focused on the leaching of gold and copper from the waste mobile phone PCBs using C. violaceum in absence/presence of H 2 O 2 to supplement the DO level.

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Bioleaching of gold from waste printed circuit boards

2014-6-20  Chromobacterium violaceum, a cyanide-generating bacterium has been used to leach out gold from the waste printed circuit boards in culture medium with yeast extract, peptone and glycine. And gold leaching efficiency is affected by many factors, such as dissolved oxygen, base metals, particle size and nutriment, especially several metal ions, which can serve as the catalyst in the metabolism.

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Gold Leaching from Printed Circuit Boards (PCBs) as

Gold Leaching from Printed Circuit Boards (PCBs) as one of the Urban Mine Resources using Thiosulphate: Optimization using Response Surface Methodology (RSM) H B T M Petrus 1,2, A E Putra 1, H S A Gustiana 1, A Prasetya 1,2, I M Bendiyasa 1,2 and W Astuti 3. Published 1 April 2020 • Published under licence by IOP Publishing Ltd

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Leaching of gold and silver from printed circuit board

The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a ...

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Thiosulfate leaching of gold from waste mobile

The present communication deals with the leaching of gold from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a copper-ammonia-thiosulfate solution, as an alternative to the conventional and toxic cyanide leaching of gold. The influence of thiosulfate, ammonia and copper sulfate concentrations on the leaching of gold from PCBs of ...

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Gold Separation of Handphone Circuit Board Scraps

2016-11-30  Figure 1: Gold separation process by using leaching process Handphone Circuit boards (PCBs) is screening into small particle sizes. This particle was analyzed by XRF (Philips Magix) and AAS to determine the metals contents of sample. Sample 5g was leaching with HNO 3 while it heated at 40 oC, then the solid

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Microbial Processing of Waste Shredded PCBs for Copper ...

2021-2-15  als from PWBs [16,17]. Chi et al. (2011) reported leaching of gold and copper from waste mobile phone printed circuit boards by using a cyanide-generating bacterium, Chromobac-terium violaceum in YP (yeast extract and polypeptone with glycine) medium [18]. Addi-tionally, fungi such as Penicillium sp. and Aspergillus niger are examples of some ...

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Effect of Acid Leaching Pre-Treatment on Gold

2021-1-13  The residue of previous leaching was leached with thiourea with the same operative conditions as those used for the leaching carried on PCBs of size −0.5 mm without preliminary treatment: thiourea concentration 25 g/L, Fe 3+ = 0.6% w/v, H 2 SO 4 0.1 mol/L (pH 1), L/S ratio 10, T 25 °C, and leach time 2 h, under stirring.

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Gold Leaching from Printed Circuit Boards (PCBs) as

Gold Leaching from Printed Circuit Boards (PCBs) as one of the Urban Mine Resources using Thiosulphate: Optimization using Response Surface Methodology (RSM) H B T M Petrus 1,2, A E Putra 1, H S A Gustiana 1, A Prasetya 1,2, I M Bendiyasa 1,2 and W Astuti 3. Published 1 April 2020 • Published under licence by IOP Publishing Ltd

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GOLD RECOVERY FROM PRINTED CIRCUIT BOARDS

In leaching tests with commercial (cyanide-based) stripping, it was possible to extract 88% of the gold present in PCBs. The advantage of using cyanide is the simplicity of the process, while its disadvantage is the high toxicity and the need for greater control in the treatment of effluents.

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Leaching of gold and silver from printed circuit board

The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a ...

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New insight on Gold and Copper leaching from waste

2020-11-27  cyanide (HCN) in a commercial medium in a continuous flow stirred-tank reactor (CSTR), b) gold and copper leaching from PCBs, and c) HCN degradation by Chromobacterium violaceum. This process was more efficient at leaching gold than it was at leaching copper. HCN production by C. violaceum in CSTR

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Gold Separation of Handphone Circuit Board Scraps

2016-11-30  Figure 1: Gold separation process by using leaching process Handphone Circuit boards (PCBs) is screening into small particle sizes. This particle was analyzed by XRF (Philips Magix) and AAS to determine the metals contents of sample. Sample 5g was leaching with HNO 3 while it heated at 40 oC, then the solid

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Microbial Processing of Waste Shredded PCBs for Copper ...

2021-2-15  als from PWBs [16,17]. Chi et al. (2011) reported leaching of gold and copper from waste mobile phone printed circuit boards by using a cyanide-generating bacterium, Chromobac-terium violaceum in YP (yeast extract and polypeptone with glycine) medium [18]. Addi-tionally, fungi such as Penicillium sp. and Aspergillus niger are examples of some ...

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Hydrometallurgical Recovery of Metals from Large

2015-9-29  Significant work has been reported on the hydrometallurgical recovery of metals from PCBs 1,22,23.HNO 3, HCl and H 2 SO 4 solutions are often used as leaching agents in hydrometallurgical ...

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Gold Recovery from PCBs with Thiosulfate as

In place of cyanide, thiosulfate was chosen as complexing agent for gold. Thiosulfate leaching can be considered a non-toxic process and the gold dissolution rates can be faster than conventional cyanidation. The electronic scraps, obtained from “end of life” mobile phones, were crushed and pre-treated with nitric acid before the leaching.

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Gold recovery from waste mobile phones PCBs using

2019-5-23  PCBs were then cut to smaller pieces of about 2 x 2 m. The pieces were crushed and milled respectively. Some of the particles were recycled back to the crusher to get finer particles. The particles were separated to particles of sizes between 0 and 1350 µm using a shaker. The comminuted fractions of the PCBs were then used in the leaching step.

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Metals Special Issue : Separation and Leaching for ...

2020-12-31  The efficiencies of metal leaching and solid degradation (SS and VSS) were found to be decreased with an increase of sludge solid content and a decrease of sucrose concentration. At 2 days of reaction time, the maximum efficiency of metal solubilization was 95,

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