溶融Cu-As, Cu-S-As, Fe-S-As系合金の活量

Abstract

The thermodynamic properties such as activities in molten arsenic alloys and phase relations between speiss and metallic lead phases have been determined by the author and co-workers because of the importance of these properties to analyze the behavior of speiss in various metallurgical processes.The activities of arsenic have been measured in molten Cu-As binary alloys at 1000°C, and in both Cu-SIAs and Fe-S-As ternary alloys at 1150°C by use of isopiestic method.The activities of arsenic and copper in Cu-As system deviate remarkably from Raoult's law at 1000°C, and values are slightly smaller than those at 1150°C which have been reported by the author and co-worker. The activity coefficients of arsenic in dilute solutiOn at 1000°and1150°C are 6.8×10-3 and 1.0×10-2respectively. The free energy of formation of Cu3 As was also obtained and is given by:ΔG°T/cal=-6, 200-6.35T (1273-1423K)In Cu-S-As and Fe-S-As ternary systems, the activity of arsenic increases with increasing sulfur content, and activity coefficient of arsenic in matte phase is much larger than in speiss. Therefore, it is clear that arsenic will be effectively removed from matte before metallic copper is formed in copper process.The activities of the other elements in the ternary systems were calculated from the activities of arsenic by using the Gibbs-Duhem ternary integration.