Effect of flux addition and reductant type in smelting process of Indonesian limonite ore in electric arc furnace

Abstract

Nickel in the form of nickel laterite ore is one of the most prominent types of mining products in Southeast Sulawesi, Indonesia. One of the utilization of laterite nickel ore is as raw material for ferronickel and NPI production. In this research, the NPI was produced from laterite nickel ore originating from Sulawesi Island in electric arc furnace (EAF). This study aims to determine the effect of the amount of flux (limestone) and type of reducing agent (coal, coke, and shell charcoal) on the content of Ni and Fe in the NPI product and metal yield. Laterite nickel ore used in this study is a type of limonite from Pomaala (Sulawesi Island). The reducing agents used are coke, coal, and coconut shell charcoal. Limestone was used as a flux to adjust the basicity of material during the smelting process of lateritic nickel ore. Reduction and melting process of limonite nickel ore to produce NPI were conducted in small EAF with capacity of 30 kg/heat. The dried pellets are reduced and melted in the EAF with added reducing agents and limestone. Based on the results of the study it can be concluded that the results of the flux addition effect obtained that the optimum Ni and Fe values were obtained on basicity of 1. The results of the reductant type effect showed that coke was the greatest reductant in this study due to the highest Ni content produced when coke used as reductant. In addition, the XRD results showed that the FeNi phase has been formed.