SURFACE AND INTERFACIAL-TENSION OF THE NI-FE-S, NI-CU-S, AND FAYALITE SLAG SYSTEMS

The surface tensions of the Ni-Fe-S system together with the Ni-Cu-S and fayalite-type slag systems were measured using the sessile drop technique. Drop images were obtained by X-ray radiography. For the Ni3S2-FeS pseudo-binary system, the surface tension of the matte increased with matte grade and showed a positive deviation from ideality with matte grade. This suggests that Ni3S2 dominates in the nickel matte system. The results also indicated that a fluctuation in the matte nickel content can alter the surface tension quite significantly. A ternary surface tension plot of the Ni-Fe-S system showed that the addition of either Ni or S to the matte alters the surface tension. On the other hand, at a constant Ni:S ratio, the addition of iron has negligible influence on the surface tension of the matte. The measured surface tension of the Ni-Cu-S system also showed a nonlinear relationship with the Cu2S content in the matte. The surface tension decreased with Cu2S content. The interfacial tension of the Ni-Fe-S and slag system was found to increase with increasing matte grade. The presence of MgO and Al2O3 in the slag did not affect the interfacial tension value.