硫代硫酸盐-EDTA-铜离子浸金体系电化学研究  

Electrochemical Study of Thiosulfate-EDTA-Copper Ion Leaching Gold System

作　　者：项朋志[1,2] 叶国华[3] Xiang Pengzhi;Ye Guoliua(School of Chemical Engineering,Yunnan Open University,Kunming 650093,China;Yunnan Vocational College of National-Defense Technology,Kunming 650022.China;College of Land and Resources Engineering,Kunming University of Science and Technology,Kunming 650022,China)

机构地区：[1]云南开放大学化学工程学院,云南昆明650093 [2]云南国防工业职业技术学院,云南昆明650022 [3]昆明理工大学国土资源工程学院,云南昆明650023

出　　处：《稀有金属》2020年第2期220-224,共5页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51304090,51764024,51604130);云南教育厅科学研究基金项目(2018js377)资助。

摘　　要：硫代硫酸盐-乙二胺四乙酸(EDTA)-铜离子浸金体系采用乙二胺四乙酸(EDTA)代替氨水作为铜的络合剂,所得到的络合物具有稳定性好,电极电势较低等优点,从理论上可以作为金的浸出液用于金的提取。本文采用Tafel曲线,开路电势,循环伏安这3种方法探究了硫代硫酸盐对金的腐蚀的影响,考查了铜离子浓度对硫代硫酸盐电化学行为影响以及硫代硫酸盐循环伏安行为,结果表明:硫代硫酸盐浓度的增加使金的腐蚀更加容易,超过0.10 mol·L-1后,由于硫代硫酸盐浓度的增加,其在金电极表面的产物导致电极的钝化,从而导致金的腐蚀变得困难;随着铜离子浓度的增加,硫代硫酸盐还原电位负移,峰电流增加,说明在该条件下,硫代硫酸盐更加容易被消耗;循环伏安表明峰电流与扫描速度平方根成直线关系,属于扩散控制,这个过程中,硫代硫酸盐还原电子转移数约为1,硫代硫酸盐循环伏安行为表明lnIp与1/T呈良好的线性关系,其活化能Ea=5.498 kJ·moL-1,说明为浓差极化所致。Disodium ethylenediamine tetraacetate(EDTA) was used as copper complex agent instead of ammonia in the thiosulfate-EDTA-copper ion system. The obtained complex had the advantages of good stability and low electrode potential. It could be used as gold leaching solution for gold extraction. The Tafel curves, the open circuit potential, cyclic voltammograms were used to explore the thiosulfate influence on the corrosion of gold, examine the cyclic voltammetric behavior. The results showed that the increase in concentration of thiosulfate could lead to easy corrosion for gold when its concentration was more than 0.1 mol·L-1, the increase of the concentration of thiosulfate could lead to the corrosion of gold difficult due to the passivation on the gold electrode surface;with the increase of copper concentration, thiosulfate reduction potential was negatively shifted and peak current increased, indicating that thiosulfate was more easily consumed under the condition. The cyclic voltammetry showed a linear relationship between peak current and square root of scanning speed, which was diffusion control. During this process, the reduction electron transfer number of thiosulfate was about 1. The cyclic voltammetry of thiosulfate also showed a good linear relationship between lnIp and 1/T, and its activation energy was Ea=5.498 kJ·mol-1, indicating that it was caused by concentration difference polarization.

关 键 词：硫代硫酸盐 乙二胺四乙酸(EDTA) Tafel曲线 开路电势 循环伏安 

分 类 号：TD953[矿业工程—选矿] TF831[冶金工程—有色金属冶金]