Abstract
As massive Ni sulfide ores are becoming depleted, ultramafic Ni sulfide ores were explored as an alternative source of Ni. Due to the amount of magnesium silicate in the ore and challenges in separating the gangue material in the concentration process, Ni cannot be extracted by conventional methods as the ultramafic Ni concentrate has a higher melting temperature than Ni sulfide concentrates. A solid-state two-stage thermal treatment and physical separation process was developed to extract Ni from ultramafic Ni concentrates in the form of a Fe-rich, sulfur-deficient FeNi concentrate. To extract the Ni from the FeNi concentrate in the form of Ni-matte, the idea of utilizing FeNi concentrate as an additional feed in a flash smelter was explored. The goal of this study was to understand the oxidation mechanism of FeNi concentrate as well as the effect of FeNi concentrate addition on the oxidation of conventional massive Ni sulfide concentrate. In this study, the reaction kinetics of concentrates with 10%, 20%, and 30% wt FeNi concentrate addition were studied.