The thermodynamic description of liquid and fcc phase in the Co-O system is obtained using available experimental data on oxygen dissolution in solid and liquid cobalt (see references in [03Che]. Thermodynamic properties of liquid are determined in the system cobalt oxide-copper oxide using experimental data of [68Dri] and [69Lan]. The experimental data [68Dri] and [69Lan] contradict each other. Depending on value of mixing parameters of liquid phase two data sets consistent with phase relations of [68Dri] or [69Lan] are obtained.
Combining data on ternary systems the thermodynamic description of solid phases in the Co-Cu-Si-O system is obtained. The mixing parameters of olivine and the Gibbs energy of fictive Cu2SiO4 end-member are subjected to optimisation procedure using experimental data on Co/Cu partitioning between olivine and (Co,Cu)O phase with halite structure obtained in this study. It is shown that several sets equally well describing experimental results are possible. The knowledge about Co/Cu partitioning between olivine and (Cu, Co)O phase with structure of CuO in equilibrium with SiO2 is crucial to constrain thermodynamic parameters for olivine.
References
[68Dri] F.C.M. Driessens, G.D. Rieck, H.N. Coenen: J. Inorg. Nucl. Chem. 30 (1968) 743-753.
[69Lan] C. Landolt, A. Muan: J. Inorg. Nucl. Chem. 31 (1969) 1319-1326.
[03Che] M. Chen, B. Hallstedt, L.J. Gauckler: J. Phase Equilibria 24 (2003) 212-226.