Floating behaviour of molten copper and Cu-matte in Cu-slag. Study on interfacial phenomena in phase separation of copper smelting (2nd paper)

Interfacial tensions in molten copper-fayalite slag and Cu-matte-fayalite slag systems were measured by sessile drop metho combined with X-ray radiophotograph. Interfacial tensions between molten copper and fayalite slag were found in the range of 0.8-0.6 N/m^-1 at 1473 K and decreases with an increase of oxygen partial pressure at the interface. Oxygen played a role of an interfacial active element in the system. While interfacial tensions between Cu-matte and the slag were rather small at low mass% Cu in Cu-matte, they become large when mass% Cu in the matte increases. Spreading and floating coefficients in the copper-fayalite slag system were negative. On the other hand, negative spreading coefficients and positive floating coefficients were obtained in the Cu-matte-fayalite slag system. It might be suggested that Cu-matte particles be floated with gas bubbles in the slag. Floatation behaviour of Cu-matte particles in the slag could be observed by X-ray radiophotograph technique.