盐酸和氯酸钠浸出铜阳极泥中金的研究

Study on leaching of gold from copper anode slime by hydrochloric acid and sodium chlorate

以铜阳极泥为原料,采用盐酸和氯酸钠为浸出剂,根据同时平衡原理,对浸出过程进行了热力学分析,考察了浸出时间、液固比、氯酸钠浓度和盐酸浓度对金浸出率的影响。研究结果表明,总金浓度[Au]T的降低和总氯浓度[Cl-]T的增加均有利于金的浸出。随着总氯浓度的增加,体系中含金物种的主要存在形态发生Au^(3+)→AuCl_3(aq)→AuCl_4^-→AuCl_2^-的转变,理论最佳浸出剂组成为盐酸与氯酸钠摩尔浓度比为6∶1。在搅拌速度为400r/min、液固比为4∶1、浸出时间为3h、盐酸浓度为3.0mol/L、氯酸钠浓度为16g/L、反应温度为25℃的条件下,金的最大浸出率为98.89%。

Thermodynamic analysis of gold leaching from copper anode slime in sodium chlorate-hydrochloric acid system was made based on the principles of simultaneous equilibrium.Many influencing factors such as leaching time,liquid-solid ratio,and concentrations of sodium chlorate and hydrochloric acid were investigated.The results show that the decrease of total gold concentration[Au]T and the increase of total chlorine concentration[Cl-]T are beneficial to leaching of gold.With the increase of total chlorine concentration,the main form of Au in solution changes following the order of Au 3+AuCl 3(aq)AuCl-4 AuCl-2.The optimum molar concentration ratio of hydrochloric acid to sodium chlorate is 6∶1 in theory.The optimum leaching conditions are that the agitation speed is 400 r/min;the liquid-solid ratio,4∶1;the leaching time,3 h;the concentration of hydrochloric acid,3.0 mol/L;the sodium chlorate concentration,16 g/L;and the reaction temperature,25℃.Under these conditions,the maximum leaching rate of gold is 98.89%.