Recovery of Valuable Metals from Waste Printed Circuit Boards by Using Iodine-Iodide Leaching and Precipitation
Recovery of Valuable Metals from Waste Printed Circuit Boards by Using Iodine-Iodide Leaching and Precipitation
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DOI：
10.1007/978-3-319-72350-1_12
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发表时间：
2018-03
期刊：
影响因子：
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通讯作者：
Altansukh Batnasan;Kazutoshi Haga;A. Shibayama
中科院分区：
文献类型：
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作者：
Altansukh Batnasan;Kazutoshi Haga;A. Shibayama
本研究提出了一种通过碘-碘浸出和沉淀从废弃印刷电路板（WPCB）中回收贵金属（Au）、银（Ag）、钯（Pd））和贱金属（Cu）、镍（Ni）、钴（Co）、铅（Pb）和锌（Zn）的可行方法。讨论了贵金属和贱金属在碘-碘浸出和沉淀过程中的溶解和沉淀行为。在碱性条件下，使用氢氧化钠（NaOH）去除浸出母液中存在的贱金属杂质。通过使用抗坏血酸（L-AA）溶液还原来回收由NaOH沉淀保留在所得溶液中的贵金属。结果表明，在最佳浸出条件下，除钙（浸出25%）外，其它贵金属（Ag、Pd）和贱金属的浸出率分别小于1%和6%时，Au几乎全部（> 99%）被碘-碘化物溶液溶解。该研究表明，超过95%的Cu，Ni，Pb，Zn，Fe和Mn最初从pH为9.3的浸出液中除去，并加入0.1 M NaOH。在此条件下，当L-AA用量为0.6 ml/ml时，用NaOH沉淀后，从所得溶液中沉淀出99.8%的Au、81.7%的Ag和74%的Pd。可以得出结论，贵金属和贱金属可以选择性地和经济地从WPCB通过碘-碘化物浸出，然后使用NaOH和L-AA沉淀。
This study presents a viable approach for recovery of precious metals such as gold (Au), silver (Ag), palladium (Pd), and base metals, including copper (Cu), nickel (Ni), cobalt (Co), lead (Pb) and zinc (Zn) from waste printed circuit boards (WPCBs) via iodine-iodide leaching and precipitation. The behaviours of dissolution and precipitation of precious and base metals during iodine-iodide leaching and precipitation processes were discussed. Sodium hydroxide (NaOH) was used to remove base metal impurities exist in the pregnant leach solution under alkaline conditions. Precious metals remained in the resulting solution from NaOH precipitation were recovered by reduction using ascorbic acid (L-AA) solution. Results show that under optimum leaching conditions, almost all (> 99%) of Au was dissolved in an iodine-iodide solution when the dissolution efficiencies of other precious metals (Ag, Pd) and base metals, besides calcium (leaching of 25%) were less than 1 and 6%, respectively. The study revealed that more than 95% of Cu, Ni, Pb, Zn, Fe and Mn were initially removed from the pregnant leach solution at pH of 9.3 with addition of 0.1 M NaOH. Then 99.8% Au, 81.7% Ag and 74% Pd were precipitated from the obtained solution after NaOH precipitation while L-AA dose was 0.6 ml/ml at the condition. It can be concluded that the precious and base metals could be recovered selectively and economically from WPCBs via iodine-iodide leaching followed by precipitation using NaOH and L-AA.