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

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.