Na₂SiO₃对碱性硫脲溶液选择性溶金的影响

来源期刊：中南大学学报(自然科学版)2003年第6期

论文作者：王云燕 柴立元 闵小波 彭兵 何德文

文章页码：611 - 614

关键词：碱性硫脲;选择性溶金; Na₂SiO₃;电化学行为

Key words：alkaline thiourea; gold dissolution selectively; Na₂SiO₃; electrochemical behavior

摘    要：采用电化学方法研究Na₂SiO₃浓度对碱性硫脲浸金的影响和金及其常见伴生元素银、铜、镍、铁在含有Na₂SiO₃的碱性硫脲溶液中的电化学行为.研究结果表明:加入Na₂SiO₃在很大程度上提高了金的溶解电流, Na₂SiO₃的最佳浓度为0.15 mol/L.分析不同电势时lgJ与lgc(Na₂SiO₃)之间的关系可得:在电势为0.42 V时, Na₂SiO₃对碱性硫脲溶液电化学溶金的促进作用最显著,含Na₂SiO₃的碱性硫脲溶液对金的溶解具有一定的选择性;在电势为0.58 V时溶 金效果最佳,金、银、镍和铁的阳极电流密度分别为2.49, 1.22, 1.03和0.09 mA/cm2;而同时加入Na₂SiO₃和Na₂SO₃时碱性硫脲溶液选择性溶金的最佳电势负移至0.42 V,对金的选择性溶解更为明显,金、银、铜、镍和铁的溶解电流密度依次为3.83, 1.13, 0.73, 0.14和0.09 mA/cm²,金的溶解电流密度分别是银、铜、镍和铁的3.4,5.2,27.3和42.6倍.

Abstract: The influence of concentration of Na₂SiO₃ongold dissolution in alkaline thiourea solutions and the electrochemical behaviors of gold and its associate elements, such as silver, copper, nickel and iron, in alkaline thiourea solutions containing Na₂SiO₃by electrochemical methods were discussed in detail. The results indicate that addition of Na₂SiO₃ into alkaline thiourea solution improves the dissolution current density of gold to a large degree, and the optimal concentration of Na₂SiO₃ is 0.15 mol/L. The relation of lgiand lgc(Na₂SiO₃) at different potentials shows that at the potential of 0.42 V, the effect of Na₂SiO₃ to gold dissolution is the biggest, and the effect of Na₂SiO₃on gold dissolution into alkaline thiourea solution is the most prominent. Electrochemical behaviors indicate that gold dissolution into alkaline thiourea containing Na₂SiO₃ is selective. At the potential of 0.58 V, gold dissolution was optimal, and the anodic current densities of gold, silver, nickel and iron are 2.49, 1.22, 1.03 and 0.09 mA/cm²respectively. However, alkaline thiourea solutions containing both Na₂SiO₃ and Na₂SiO₃ have good evident selectivity for gold dissolution. The optimal potential moves negatively to 0.42 V, and the selectivity is more evident. The anodic current densities of gold, silver, copper,nickel and iron are 3.83, 1.13, 0.73, 0.14 and 0.09 mA/cm2respectively, and then current density of gold is 3.4,5.2, 27.3 and 42.6 times of silver, copper, nickel and iron respectively.

基金信息：国家自然科学基金资助项目