<Original Papers>Equilibrium Relations between Liquid Copper, Matte and Calcium Ferrite Slag at 1250℃

The equilibrium relations of constituent elements between matte and calcium ferrite slag have been studied. The experiments were carried out at 1250℃ under controlled SO_2 pressure or inert gas atmosphere for the three-liquid phases of metallic copper-matte-slag and the two-liquid phases of matte-slag. The experimental results of the calcium ferrite slag showed considerably different equilibrium behaviours as compared with those of the silica-saturated iron silicate slag. The contents of sulfur and copper in the calcium ferrite slag increased with decreasing copper content in matte, which is closely related to the mutual dissolution between matte and slag. Therefore, it has been concluded that the calcium ferrite slag has no advantage over the iron silicate slag for the separation of slag from matte, although the present experimental results are quite interesting from the theoretical standpoint of mutual dissolution between matte and slag. The distribution ratios of lead with the calcium ferrite slag were about one-tenth smaller than those with the iron silicate slag. Thus, lead is less concentrated into the calcium ferrite slag in comparison with the iron silicate slag