Characterization of smelter slags

The chemical and phase compositions of four different slags were studied with emphases on the form of Nickel, Cobalt and Copper. These were INCO slow cooled (IS), INCO fast cooled (IF), Falconbridge-Sudbury fast cooled (FFS) and Falconbridge-Timmins fast cooled (FFT) slags. The amount of each of Ni, Co and Cu in all the slags was less than 1%. IS contained the highest amount of Ni and Co of 0.57% and 0.21% respectively. The highest Cu content was found in FFS (0.87 %). The form of Co in all the slags was primarily oxide (> 98%). However, significant portions of Ni and Cu (20%) in IF and IS slag were in the sulphide form. Finer fi actions (<270 mesh) of these slags were richer in sulphide forms of Ni and Cu (40%). X-ray analysis revealed FFS and FFT as predominantly amorphous. Both slags were homogenous, consisting of mainly iron silicate glass. However, IF and IS slags were mostly crystalline, with two predominant phases, fayalite and spinel. In addition, a smaller amount of feldspar (albite) was observed in IS. Reflected light microscopy observation showed more crystalline phases in IS than IF. SEMEDS analysis, EMPA elemental mapping and reflected light microscopy studies all indicated the presence of entrained sulphide particles in the slag samples.