Recovery of Gold and Silver from Secondary Sources of Electronic Waste Processing by Thiourea Leaching
Recovery of Gold and Silver from Secondary Sources of Electronic Waste Processing by Thiourea Leaching
复制标题
DOI：
10.1007/s11837-018-2965-2
复制
发表时间：
2018-08-01
期刊：
影响因子：
2.6
通讯作者：
Mishra, Brajendra
中科院分区：
文献类型：
--
作者：
Lee, Hyunju;Molstad, Emily;Mishra, Brajendra
在电子废物（e-waste）的处理过程中产生的诸如烟道灰的精细材料含有诸如Au和Ag的有价值的金属资源。然而，从这种烟道灰中回收有价值的金属还没有被广泛研究。本文研究了一种有效回收烟道灰中Au和Ag的浸出工艺。特别是用硫脲代替氰化物作为浸出剂，存在环境问题。系统地考察了浸出时间（1-10 h）、硫脲浓度（20-60 g/L）、纸浆密度（20-100 g/L）和反应温度（20- 60 A ° C）等参数对工艺的影响。提出了一步浸出法和两步浸出法分别回收Au和Ag。采用硫脲一步浸出，Au和Ag的浸出率分别达到90%和100%。然而，金属如Fe和Al也溶解在一起。在两步法工艺中，首先用H2SO 4溶解铁和铝，然后用硫脲浸出回收Au和Ag。使用该两步工艺，Au和Ag以比使用一步浸出工艺时更高的纯度溶解，分别实现约98%和100%的浸出效率。这项调查将导致一个具有成本效益的方法，从二次废物中回收贵金属。
Fine materials, such as flue dust, generated during processing of electronic waste (e-waste) contain valuable metal resources, such as Au and Ag. However, recovery of valuable metals from this flue dust has not been extensively studied. In this study, a leaching process was investigated for effective recovery of Au and Ag from flue dust. In particular, thiourea was used as leaching reagent to replace cyanide, which has environmental problems. The effects of various parameters on the process, such as leaching time (1-10 h), thiourea concentration (20-60 g/L), and pulp density (20-100 g/L) as well as reaction temperature (20-60A degrees C), were systematically examined. One- and two-step leaching methods were proposed to recover Au and Ag, respectively. Au and Ag leaching efficiencies of about 90% and 100% were obtained by one-step thiourea leaching. However, metals such as Fe and Al were also dissolved together. In the two-step process, Fe and Al were dissolved using H2SO4 as a first step, then Au and Ag were recovered using thiourea leaching. Using this two-step process, Au and Ag were dissolved at higher purity than when using the one-step leaching process, achieving leaching efficiencies of about 98% and 100%, respectively. This investigation will lead to a cost-effective method for recovering precious metals from secondary waste.