Fundamental Researches on Smelting of Sulphide Ores. VII : On the Equilibrium in the Reduction of Copper Sulphide in Molten Copper by Hydrogen Gas

With a view of acquiring a basis for the thermodynamic treatment of reactions involving sulphur in molten copper, the equilibrium in the reduction of copper sulphide in liquid copper by hydrogen gas was investigated with the aid of the flow method for the temperature range of 1,115～1,245℃. The equilibrium constant and the standard free energy change in the reaction were established as a function of temperature as follows : Cu_2S(in liq. Cu)+H_2=2Cu(liq.)+H_2S ; K=P_S/P_[%S]=K_p/[%S], log K=- 3, 400/T-0.024, ΔF°=15, 552+0.110T. Combining the equations above mentioned with those of hydrogen sulphide gas, the following equations on the dissociation of copper sulphide dissolved in liquid copper were obtained : 2Cu_2S(in liq. Cu)=4Cu(liq.)+S_2 ; K\u27=P_/ [%S]^2, log K\u27=-16, 186/T+5.052, ΔF°=74, 040-23.11T. Using these results, theoretical considerations on the relations between copper, sulphur and hydrogen were carried out from the standpoint of equilibrium theory