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

Interfacial tension in molten copper-fayalite slag and Cu matte-fayalite slag systems has been measured by the sessile drop method combined with X-ray radiophotography. Interfacial tension between copper and fayalite slag was in the range 0.8-0.6 N/m^-1 at 1473 K and decreased with the increase of oxygen partial pressure at the interface. While interfacial tension between Cu matte and the slag was small at low mass%Cu in Cu matte it increased when mass% Cu in the matte increased. 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-slag system. Matte particles may be floated with gas bubbles in the slag.