关于硫脲法的几个基本问题的讨论

Discussion of a few fundamental problems of the thiourea process

本文讨论了硫脲法提金中的三个基本问题1、硫脲-二硫甲脒的电极电位。这个电位与pH无关,在电位—pH图上应为一斜率为零的直线。2.Fe(Ⅲ)—硫脲体系的电位。由于在一定条件下,Fe^(3+)与硫脲之间的氧化还原反应速度甚慢,当反应未完成前,两者处于非平衡状态,此对所测得的电位不能用于计算体系中各电对的反应物之浓度。3.金在硫脲溶液中的溶解速度,前述非平衡体系具有较高的游离硫脲浓度和氧化电位,因此在这个体系中,金的溶解速度比已达平衡的体系为快。如浸取矿金的体系也处非平衡状态,则不但浸取速度快,而且硫脲消耗少。

The three fundamental problems of the thiourea process have been dis-ussed in this paper. 1.The potential of thiourea-formamidine disulfide. The potential is independent on pH and it is a straight line with slope of zero in Eh-pH diagram. 2. The potential of Fe (111) -thiourea system. In some conditions the redox reaction between Fe8+ and thiourea is very slow and the system is in nonequilibrium state before the reaction reaches equilibrium. The potential measured can not be used to estimate the activities of the reaction species of each couples in the system. 3. The dissolution rate of gold in the thiourea solution.The nonequilibrium system described before has higher concentration of isolate thiourea and higher potential value than that in the system which has reached the equilibrium. Then the dissolution rate of gold in the former is quicker than in the latter. If the leaching system of ore gold is in the nonequilibrium state, it possesses not only higher leach rate but also less consumption of thiourea.