LAUSR

Abstract Copper and cobalt are two of the most valuable metals that can be recovered from copper converter slag. In the reduction–vulcanization process, copper is reduced before cobalt, while FeS vulcanizes Cu2O into Cu2S and forms the matte phase. The matte phase can dissolve the reduced metals as solvent. In this study, the distribution coefficient of cobalt between metallic cobalt in matte and CoO in slag, namely LCo, was calculated to be 5000–8500 at the reaction temperature of 1600–1700 K, while the distribution coefficient between CoS and CoO, namely $$L_{\text{Co}}^{{^{\prime } }}$$LCo′, was calculated to be between 6 and 8. The distribution coefficient of copper between metallic copper in matte and Cu2O in slag, namely LCu, was calculated to be in the range of 7500–8500, while the coefficient between Cu2S and Cu2O, namely $$L_{\text{Cu}}^{{^{\prime } }}$$LCu′, was calculated to be in the range of 60,000–75,000.