Manganese ores from South Sulawesi: Their potential uses as raw material for metallurgical industry

Abstract

— Characterization of manganese ores from Barru and Bone regencies of South Sulawesi has been conducted with the aim at clarification of their mineralogical and chemical composition for their potential uses as the raw materials for metallurgical industry. Mineralogical properties of the ores analyzed by means of optical microscopy and X-ray diffractometry (XRD) show that samples from Barru consist mainly of rhodochrosite (MnCO 3 ) with less cryptomelane, groutite, bixbyite, and todorokite. Goethite, calcite and small amount of quartz present as impurities. Manganese ore samples from Bone are predominantly composed of pyrolusite (MnO 2 ) with subordinate ramsdellite and hollandite. Barite, quartz, hematite and clay are present as gangue minerals. Chemical compositions determined by using XRF method revealed that Barru samples contain higher in MnO (average is 40.07 wt%) than the Bone samples (average is 34.36 wt%). Similarly, Fe 2 O 3 and CaO are also higher in Barru than those of the Bone samples. In contrast, concentrations of SiO 2 and total alkali (K 2 O + Na 2 O) are lower in the Barru samples. The average P 2 O 5 content of samples in both areas is low (<0.2 wt%). Relatively higher grade of Fe 2 O 3 in the Barru ore implies that it has potential application for ferromanganese production; whereas the elevated SiO 2 content of the Bone ore is a good indication for silicomanganese manufacture. However, both ores may not favorable to be directly used as raw materials in metallurgical uses. Prior to be used, the ores should be treated by applying physical beneficiation in order to reduce deleterious elements.