BENEFICIATION OF LOW GRADE LATERITIC NICKEL ORE FROM SOUTHEAST SULAWESI USING MECHANOCHEMICAL PROCESS AND MAGNETIC SEPARATION

• Main Author: Riandi Rais, Andi
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/45165
• Institution: Institut Teknologi Bandung

Nickel is a metal, that when it is alloyed with iron, chrome and other metals, it can be produced a hard, slightly ferromagnetic and good conductor of stainless steel. Nickel metal in a form of alloy is widely used in industry such as stainless steel, chemical, electroplating, and other metal alloy industries. In nature, nickel is usually mined from two main types of ore, namely sulfide and oxide (laterite) ores. Indonesia has approximately 15.7% of world nickel laterite deposits. Currently, the nickel concentration process from the ore is still unsuccessful due to the complexity of ore mineralogy, amorphous structure, association with iron oxide and silicate minerals, equitable distribution of particles and very fine size (up to nanometer size) so physical beneficiation is difficult to be done. In this study, mechanochemical grinding process was carried out with the addition of coal and sulfuric acid also without addition of coal and sulfuric acid using a planetarry ball mill followed by magnetic separation. The effects of grinding times and coal and sulfuric acid addition have been studied as influential variables in the experiment. The grinding times used 5, 15, 35 and 50 hours while the amounts both for coal and sulfuric acid added were 5% and 6%. Magnetic separation experiment has been done through wet technique with 1000 gauss magnetic intensity. The results of experiments showed that the laterite nickel ores from Southeast Sulawesi contain goethite, hematite, krisotil, gaspeite and quartz minerals with nickel was evenly distributed in the ore. The results of mechanochemical experiments showed that longer grinding time would increase Ni and Fe contents. The initial Ni content was 1.45%, then it increased up to 2.36% without adding coal and sulfuric acid, to 2.22% with the addition of reductor, to 2.33% with the addition of sulfuric acid and up to 2.35% with the addition of reductor and sulfuric acid. For Fe, the initial level was 30.47% then it increased up to 54.65% without the addition of reducing agents and sulfuric acid, to 52.18% with the addition of reducing agents, to 53.19 with the addition of sulfuric acid and up to 51.07% with the addition of reducing agents and sulfuric acid. The increase in Ni content was iv due to the increase in Ni selectivity and the reduction temperature of steel balls was going up, where the higher temperature, the higher the level would be. As for Fe, it is estimated that there was phase change from goethite to hematite or magnetite with particle distribution size D90 was 67.71 ?m. The magnetic separation process gave the best result which contains 2.61% of Ni and 53.28% of Fe with the recovery Ni 73.3% and the recovery Fe 68.84%.