DISTRIBUTION BEHAVIOR OF COBALT, SELENIUM, AND TELLURIUM BETWEEN NICKER-COPPER-IRON MATTE AND SILICA-SATURATED IRON SILICATE SLAG

The distribution coefficients (D-x) of cobalt, selenium, and tellurium between nickel-copper-iron matte and silica-saturated iron silicate s lag were determined as a function of matte and slag compositions, temp erature, and the partial pressure of oxygen. The effect of slag additi ves, such as CaO, MgO, and Al2O3, on the distribution behavior of the minor elements was also investigated. Analysis of the data indicated t hat D-Co, D-Se, and D-Te were-strongly dependent on the matte grade an d slag additives. The effect of slag additives on the solubility of Co , Se, and Te in slag was discussed in terms of various experimental co nditions. Cobalt distribution coefficients were found to decrease with increasing oxygen partial pressure, indicating the oxidic dissolution of cobalt in the slag. Based on the experimental results and availabl e thermodynamic data, the activity coefficients of CoS in the nickel-c opper-iron matte were estimated as a function of mole fraction of FeS in the matte at 1250 degrees C. Meanwhile, the distribution coefficien ts of both selenium and tellurium increased when raising the partial p ressure of oxygen, implying that there was molecular dissolution of se lenium and tellurium in the slag within the oxygen partial-pressure ra nge investigated in this study.