High-Pressure Oxidative Leaching and Iodide Leaching Followed by Selective Precipitation for Recovery of Base and Precious Metals from Waste Printed Circuit Boards Ash
High-Pressure Oxidative Leaching and Iodide Leaching Followed by Selective Precipitation for Recovery of Base and Precious Metals from Waste Printed Circuit Boards Ash
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DOI：
10.3390/met9030363
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发表时间：
2019-03-20
期刊：
影响因子：
2.9
通讯作者：
Shibayama, Atsushi
中科院分区：
文献类型：
--
作者：
Batnasan, Altansukh;Haga, Kazutoshi;Shibayama, Atsushi
研究了高压氧化浸出（HPOL）预处理、碘化浸出-还原沉淀法从废印刷电路板（WPCB）灰中回收金的工艺。在高温下使用稀硫酸溶液通过HPOL去除WPCB灰中存在的贱金属。研究了碘化钾浓度、过氧化氢浓度、硫酸浓度、浸出温度和浸出时间对KI-H2 O2-H2SO 4体系从金屑中提取金的影响。在不同的矿浆密度范围从50 g/t到200 g/t，考察了从HPOL后获得的浸出渣中提取金的优化碘化物浸出工艺的适用性。结果表明，在一定条件下，铜、锌、镍、铝、钴和铁的去除率分别为99%、95.7%、91%、87.3%、82%和70%。在最佳条件下，金片和多氯联苯残渣中的金提取率分别为99%和95%。用氢氧化钠和L-抗坏血酸顺序沉淀，从浸出液中选择性地沉淀出约99%的金。最后，通过整体组合工艺，从WPCB灰中实现了93%以上的金回收率。
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.