The Processing of Low Grade Nickel Ore from South East Sulawesi

Abstract

The deposit of nickel ore in Indonesia is very abundant. High grade ore has been processed to produce ferronickel, but low grade nickel ore is still left as by product without being processed. This kind of ore has been attempted to be processed through atmospheric leaching and carbon reduction, separately. In atmospheric leaching process, it is found that iron and nickel can be separated from other minerals through leaching in acid media. The performance of process is influenced by certain process variables such as temperature and acid concentration. At high temperature and high acid concentration, at least 80 % of nickel and 95 % of iron can be extracted in less than 3 hours. The recovery profile of nickel and iron are similar. Nickel and iron extraction increase with an increase in acid concentration and temperature. Another type of process, reduction smelting, results in sponge iron that can be smelted to produce iron-nickel alloy. The ore was reduced by carbon at temperature range of 800 - 1200 °C. The progress of reduction reaction between oxide minerals and carbon depends on reduction temperature. At high temperature, the reduction reaction takes place rapidly. The reduced ores was smelted to obtain iron-nickel alloy.