Mineralogical Study of Bauxite of Kenco Area, Landak District, West Kalimantan Province, Indonesia

Abstract

Indonesia is a country with a tropical climate that allows for high levels of weathering. Bauxite is the result of weathering rocks that have high aluminum content, low iron content, and little quartz content. The formation of bauxite deposits is controlled by source rock which is rich in Al element, tropical climatic conditions, and geomorphological conditions that allow the formation of the accumulation of weathered source rock products. The altered silicate minerals due to weathering result in the silica element being released from the crystal bonds and some iron are released so that the aluminum element is concentrated as a residual precipitate. X-ray diffraction (XRD) analysis on 16 bauxite samples which are estimated to represent the overburden horizon, bauxite ore horizon, clay horizon, and source rock to establish the mineral composition of bauxite. Mineral groups in the overburden horizon, bauxite ore horizon, and clay horizon are alumina, iron, titanium, silicates, carbonates, sulfides, and sulfates, while mineral groups in source rock are iron, titanium, silicate, sulfide, and sulfate. The type of bauxite in the study area is gibbsite bauxite based on the dominant appearance frequency of gibbsite compared to mineral corundum as an alumina group.