SiO<sub>2</sub>/MgO Ratio Effect on Carbothermic Reaction of Synthetic Nickelliferrous Mixtures

Abstract

The objective of this study is to understand the effect of SiO2/MgO ratio on the reducibility of Fe and Ni in the synthetic nickel laterite mixtures of similar composition to Indonesia saprolitic nickel ore. The samples were made with addition (in wt% basis ) of 12% cokes, 2 % NiO, and varied SiO2 of 0 %, 10 %, 20%, 30%, and 40 % . Two types of samples were made, with and withou 14% MgO addition. Fe2O3 was added to both types of samples as balance. The synthetic compounds were mixed homogenously and compacted, before subjected to carbothermic reduction process at temperature of 1250 °C for 120 minutes. The results showed that Ni was strongly influenced by MgO content after reduction processes. Higher content of MgO was more unfavorable for nickel reduction, while a higher content of SiO2 was unfavorable for Fe reduction. According to the characterization results of carbothermic product, nickel oxide had been reduced to form Fe-Ni phase. Nickel recovery tends to increase with increasing of SiO2 addition on sample with MgO addition.