Distribution Behavior of Nickel, Cobalt, and Copper between Al₂O₃–Li₂O–CaO Slag or Al₂O₃–Li₂O–SiO₂ Slag and Molten Ni–Co–Cu Alloy at 1623 K

Abstract

The distribution of Ni, Co, and Cu between the Al₂O₃–Li₂O–CaO slag or the Al₂O₃–Li₂O–SiO₂ slag and the Ni–Co–Cu alloy at 1623 K was investigated. In the oxygen partial pressure (p_O2) range of 10⁻¹⁴ to 10⁻¹², the distribution ratio, L_X, of component X (X: Co, Ni, or Cu) between the Al₂O₃–Li₂O–CaO slag and the molten Ni–Co–Cu alloy was L_Ni < L_Cu < L_Co. The valences of Ni and Co in the Al₂O₃–Li₂O–CaO slag system are mainly divalent, and that of Cu is mainly monovalent, as determined from the log p_O2 dependence of log L_X in the p_O2 range of 10⁻¹⁴ to 10⁻¹². The p_O2 of the Al₂O₃–Li₂O–CaO system is three to five orders of magnitude lower than that of the Al₂O₃–Li₂O–SiO₂ system and the previously reported slag system without Li₂O, even though the distribution ratios (L_Ni, L_Co, and L_Cu) are similar. The activity coefficients of Ni, Co, and Cu in the Al₂O₃–Li₂O–CaO system are all lower than those in the Al₂O₃–Li₂O–SiO₂ system and the previously reported slag system without Li₂O. In particular, [γ_CoO] is approximately two orders of magnitude lower.

Fig. 10 Comparison of γ_CoO determined in this study at 1623 K with previously reported values.