The thermodynamics of the Fe-Co-S ternary system

The thermodynamic properties of the Fe-Co-S ternary system were determined by equilibrating the system with a known sulphur pressure established by us ing a gas mixture of H2S/H-2 at 1473, 1548 and 1623 K. The iso-activity con tours for Fe and Co were established by application of the Gibbs Duhem equa tion using Schuhmann's method for ternary systems. For this purpose a compu ter program was used to calculate the activities of iron and cobalt. The co balt activity coefficients in dilute solutions of cobalt in the iron-cobalt -sulphur system, which are of industrial interest, were determined. From th e experimental data, the partial heats of solution for iron, cobalt, and su lphur and the integral heats of solution for the Fe-Co-S ternary systems we re derived. (C) 2000 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.