金电极在硫代硫酸盐溶液中的电化学氧化机理研究

Electrochemical oxidation mechanism of gold electrodes in thiosulfate solutions

硫代硫酸盐浸金体系因其成本低、无毒、浸出速度快而被视为替代氰化浸金最有前途的工艺之一,但其存在浸金体系复杂,浸金机理不明确,金的溶解和沉积机理有待进一步研究等问题,因此深入研究硫代硫酸盐浸金机理具有重要意义。基于此,采用开路电位、循环伏安、Tafel曲线和电化学阻抗谱等电化学测量技术,研究金电极在pH值为10.0的不同浓度硫代硫酸盐溶液中的电化学氧化机理,同时讨论了该浸金体系的氧化还原反应。结果表明:硫代硫酸盐浓度越高,越有利于金的溶解,但过高的浓度又会影响其氧化速率;高浓度的硫代硫酸盐会改变电子转移速度,加快金电极表面的氧化速率;金电极的氧化速率主要由表面氧化决定。该研究将加深对硫代硫酸盐浓度对金电极电化学氧化机理影响的认识,为硫代硫酸盐浸金的实际应用提供理论参考。

Thiosulfate gold leaching system is regarded as the most promising alternative to cyanide gold leaching because of its low cost,non-toxicity and fast leaching rate.However,there are problems such as the complexity of the leaching system,the unclear mechanism of gold leaching,the dissolution and deposition mechanism of gold that are needed to be further studied,so it is important to study the mechanism of thiosulfate gold leaching.Based on this,the oxidation mechanism of gold electrode in thiosulfate was studied by means of electrochemical measurement.The oxidation mechanism of gold electrode in different concentrations of thiosulfate solution with pH value of 10.0 was tested by open circuit potential,cyclic voltammetry,Tafel curve and electrochemical impedance spectroscopy.At the same time,the redox reaction of the gold leaching system is discussed.The results showed that the higher the concentration of thio-sulfate,the more conducive to the dissolution of gold,but too high concentration will affect its oxidation rate;high concentration thiosulfate will affect the charge transfer speed,accelerating oxidation rate of gold electrode surface;the electrode oxidation rate is mainly affected by surface oxidation.The study will deepen the understanding of the effect of thiosulfate concentration on gold electrode oxidation mechanism and provide theoretical reference for the practical application of thiosulfate gold leaching.