硫代硫酸盐法浸出废旧IC芯片中金的试验研究

介绍了当前电子废弃物中常用的浸金方法及其优缺点, 分析了电子废弃物中硫代硫酸盐法浸金的研究现状。针对这一研究现状, 本文采用碱性Na₂S₂O₃溶液中添加Cu²⁺的方法, 对废旧IC(integrated circuit)芯片中金的浸出进行了试验研究。通过对IC样品进行机械预处理、粒度分析、解离度分析、化学预处理和浸金试验, 探讨了Na₂S₂O₃浓度、Cu²⁺浓度、NH₃浓度、浸出温度、浸出时间和反应液固比6个因素对金浸出率的影响。试验得出最佳浸金条件为:Na₂S₂O₃浓度0.3mol/L, Cu²⁺浓度0.03mol/L, NH₃浓度0.5mol/L, 添加3.5g/L的Na₂SO₃作为稳定剂, 浸取温度50℃, 浸取时间2.5h, 液固比10:1, 在最佳浸出条件下, 金的最高浸出率为92.25%。与传统方法相比, 该方法具有浸出速度快、浸出液无毒、操作简单等优点, 是一种具有开发潜力的电子废弃物浸金方法。

Experimental study of gold leaching from waste IC with thiosulfate

This paper described the current commonly e-waste gold leaching methods, their advantages and disadvantages, and analyzed research status of e-waste thiosulfate gold leaching. Gold leaching from waste integrated circuit (IC) using the alkaline sodium thiosulfate solution with copper iron was investigated. Through the mechanical pretreatment, particle size analysis, dissociate-ion analysis, chemical pretreatment and gold leaching experiments, the effects on gold leaching rate of Na₂S₂O₃ concentration, Cu²⁺ concentration, NH₃ concentration, temperature, leaching time and liquid to solid ratio were discussed, and optimum gold leaching conditions were obtained:0.3mol/L of Na₂S₂O₃, 0.03mol/L of Cu²⁺, 0.5mol/L of NH₃, 3.5g/L of Na₂SO₃ as the stabilizer, leaching temperature of 50℃, leaching time of 2.5h, liquid to solid ratio of 10:1. Under these conditions, the highest rate of gold leaching was 92.25%. Compared with traditional methods, the new method had advantages of fast leaching speed, non-toxic leachate and easy operation.