Thermodynamic properties of cobalt oxysulphide melts

摘要

Based on the interaction mechanism of oxygen with molten copper, nickel and cobalt sulphide, a method for calculating the thermodynamic properties of the oxysulphidic melts of these metals has been proposed. The method has been tested using as example the system Cu-S-O as well as the data which were published earlier by the present author. The calculations of the equilibrium content of oxygen and sulphur in the homogeneous melts of the system Co-S-O has been carried out at 1500 deg C: the boundary for the equilibrium of solid cobalt oxide with the oxysulphide liquid phases as a function of Pso_2 been determined. It has been shown that an increase in the solubility of oxygen in cobalt sulphide increases the activity of sulphur and Pso_2, Ps_2 and Po_2, and a decrease of the activity coefficient of the oxygen and an increase of the activity coefficient of the sulphur. The established regularities of the variation of the thermodynamic properties of the oxysulphidic melts indicate that they are not dilute liquid phases with respect to oxygen, but that they are characterised by strong metal sulphur and oxygen interaction.