Recovery of Valuable Metals from Waste Printed Circuit Boards by Using Iodine-Iodide Leaching and Precipitation

Altansukh, Batnasan; Haga, Kazutoshi; Shibayama, Atsushi

doi:10.1007/978-3-319-72350-1_12

Cited by 5 publications

(9 citation statements)

References 15 publications

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“…Xu et al reported that the gold extraction reached approximately 95% under the optimum conditions: an iodide concentration of 1.0-1.2%, H 2 O 2 concentration of 1-2%, leaching time of 4 h, solid/liquid ratio of 1/10, pH 7 and 25 • C [27]. Batnasan et al [28] demonstrated an iodine-iodide leaching process to recover valuable metals from waste printed circuit boards. The results indicated that more than 99% of gold was dissolved, while less than 1% of silver and palladium were dissolved at the conditions: iodine/iodide mass ratio of 1/6, pulp density of 10%, agitation speed of 500 rpm, 24 h and 40 • C [28].…”

Section: Cyanidementioning

confidence: 99%

“…Batnasan et al [28] demonstrated an iodine-iodide leaching process to recover valuable metals from waste printed circuit boards. The results indicated that more than 99% of gold was dissolved, while less than 1% of silver and palladium were dissolved at the conditions: iodine/iodide mass ratio of 1/6, pulp density of 10%, agitation speed of 500 rpm, 24 h and 40 • C [28].…”

Section: Cyanidementioning

confidence: 99%

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Hydrometallurgical Treatment of Waste Printed Circuit Boards: Bromine Leaching

Cui¹,

Anderson

2020

Metals

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This paper demonstrates the recovery of valuable metals from shredded Waste Printed Circuit Boards (WPCBs) by bromine leaching. Effects of sodium bromide concentration, bromine concentration, leaching time and inorganic acids were investigated. The most critical factors are sodium concentration and bromine concentration. It was found that more than 95% of copper, silver, lead, gold and nickel could be dissolved simultaneously under the optimal conditions: 50 g/L solid/liquid ratio, 1.17 M NaBr, 0.77 M Br2, 2 M HCl, 400 RPM agitation speed and 23.5 °C for 10 hours. The study shows that the dissolution of gold from waste printed circuit boards in a Br2-NaBr system is controlled by film diffusion and chemical reaction.

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Section: Cyanidementioning

confidence: 99%

Section: Cyanidementioning

confidence: 99%

Hydrometallurgical Treatment of Waste Printed Circuit Boards: Bromine Leaching

Cui¹,

Anderson

2020

Metals

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“…3.5.1. Removal of Metal Impurities from the PLS Based on the preliminary experimental results [25,40], the pH of the PLS was adjusted up to 9.0 from 1.9 using 0.1 M NaOH at ambient temperature and stirring speed of 500 rpm. The efficiency of metals precipitation is shown in Figure 10.…”

Section: Removal Of Metal Impurities From the Plsmentioning

confidence: 99%

“…Metals remained in the alkaline solution that resulted from the precipitation of base metals with NaOH were recovered by reductive precipitation using a 0.1 M, L-AA solution under conditions that were fixed as the molar ratio between Au and L-AA of 1:1, temperature of 25 °C, stirring speed of 500 rpm and precipitation time for 10 min [25,40]. Figure 11 shows the recovery of metals like Au, Cu, Ni, and Pb from the solution via precipitation with L-AA.…”

Section: Recovery Of Gold From the Solution By Reductive Precipitatiomentioning

confidence: 99%

“…Removal of metal impurities from the pregnant leach solution (PLS) by precipitation at pH 9.3.5.2. Recovery of Gold from the Solution by Reductive Precipitation Using L-AAMetals remained in the alkaline solution that resulted from the precipitation of base metals with NaOH were recovered by reductive precipitation using a 0.1 M, L-AA solution under conditions that were fixed as the molar ratio between Au and L-AA of 1:1, temperature of 25 • C, stirring speed of 500 rpm and precipitation time for 10 min[25,40].Figure 11shows the recovery of metals like Au, Cu, Ni, and Pb from the solution via precipitation with L-AA.Metals 2019, 9, 363 13 of Recovery of metals from the solution by reductive precipitation with L-AA.…”

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confidence: 99%

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High-Pressure Oxidative Leaching and Iodide Leaching Followed by Selective Precipitation for Recovery of Base and Precious Metals from Waste Printed Circuit Boards Ash

Altansukh

Haga

Huang

et al. 2019

Metals

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: This paper deals with the recovery of gold from waste printed circuit boards (WPCBs) ash by high-pressure oxidative leaching (HPOL) pre-treatment and iodide leaching followed by reduction precipitation. Base metals present in WPCB ash were removed via HPOL using a diluted sulfuric acid solution at elevated temperatures. Effects of potassium iodide concentration, hydrogen peroxide concentration, sulfuric acid concentration, leaching temperature, and leaching time on gold extraction from pure gold chips with KI–H2O2–H2SO4 were investigated. The applicability of the optimized iodide leaching process for the extraction of gold from the leach residue obtained after HPOL were examined at different pulp densities ranging from 50 g/t to 200 g/t. Results show that the removal efficiency was 99% for Cu, 95.7% for Zn, 91% for Ni, 87.3% for Al, 82% for Co, and 70% for Fe under defined conditions. Under the optimal conditions, the percentage of gold extraction from the gold chips and the residue of WPCBs was 99% and 95%, respectively. About 99% of the gold was selectively precipitated from the pregnant leach solution by sequential precipitation with sodium hydroxide and L-ascorbic acid. Finally, more than 93% of gold recovery was achieved from WPCB ash by overall combined processes.

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