Na2SiO3对碱性硫脲溶液选择性溶金的影响

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0.15mol/L.分析不同电势时lgJ与lgc(Na2SiO3)之间的关系可得:在电势为0.42V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0.58V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0.09mA/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0.42V,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0.09mA/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.

Effect of Na2SiO3 on gold dissolution selectively in alkaline thiourea solutions

The influence of concentration of Na_2SiO_3 on gold 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 Na_2SiO_3 by electrochemical methods were discussed in detail. The results indicate that addition of Na_2SiO_3 into alkaline thiourea solution improves the dissolution current density of gold to a large degree, and the optimal concentration of Na_2SiO_3 is 0.15 mol/L. The relation of lgi and lgc(Na_2SiO_3) at different potentials shows that at the potential of 0.42 V, the effect of Na_2SiO_3 to gold dissolution is the biggest, and the effect of Na_2SiO_3 on gold dissolution into alkaline thiourea solution is the most prominent. Electrochemical behaviors indicate that gold dissolution into alkaline thiourea containing Na_2SiO_3 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/cm~2 respectively. However, alkaline thiourea solutions containing both Na_2SiO_3 and Na_2SO_3 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/cm~2) respectively, and then current density of gold is 3.4, 5.2, 27.3 and 42.6 times of silver, copper, nickel and iron respectively.