Equilibrium distribution of Fe,Ni, Sb,and Sn between liquid Cu and a CaO-rich slag

Equilibrium measurements of the distribution of Fe, Ni, Sb, and Sn between a liquid Cu-O solution and a CaF₂-CaO-MgO-SiO₂ were carried out at 1500 K in a magnesia crucible. The results show that the studied solutes were in the states Fe(III), Ni(II), Sb(III), and Sn(IV), in the slag, for metal O contents ranging from 100 ppm to saturation at 2.1 pct. The Cu oxide solubility in the slag was also measured in absence of the solute elements. Its maximum solubility is about 4 ± 1 mass pct Cu₂O. The compositions at equilibrium allow determination of the activity coefficients (referred to pure oxide) of the four solute oxides in the slag. These values, expressed in round figures to take into account the experimental uncertainties, are 10 for Fe₂O₃, 20 for NiO, 10 for SnO₂, 1.6 10⁻² for SbO_1.5, and 60 for Cu₂O.