Fundamental Researches on Smelting of Sulphide Ores. VI : On the Equilibrium in the Reduction of Solid Cuprous Sulphide by Hydrogen Gas

The equilibrium in the reduction of solid cuprous sulphide by hydrogen gas was studied by means of the dynamical method over the temperature range 727~872℃. The equations for the temperature dependence of the equilibrium constant and the standard free energy change in the reaction were obtained as follows : Cu_2S(β)+H_2=2Cu+H_2S ; log K_p=-2, 140/T-0.962, ΔF°=9, 788+4.400T. By combining the equations with the known ones of hydrogen sulphide gas, the dissociation pressure and the standard free energy change in the dissociation reaction of solid cuprous sulphide were represented as a function of temperature by the following equations : 2Cu_2S(β)=4Cu(s)+S_2 ; log P_<S_2>=-13, 666/T+3.176, ΔF°=62, 510-14.527T. Using these results and other thermodynamical data, the heat change and the standard free energy change of formation of solid cuprous sulphide were calculated. 2Cu+S(r)=Cu_2S(α); ΔH298.1=-19, 940, ΔF°298.1=-21, 290.