Critical raw materials associated with the lateritic bauxite and red mud in West Kalimantan, Indonesia

Abstract

The Western Indonesia Bauxite Province in Kalimantan forms a lateritic bauxite region with a complex history and poorly known sustainable metal contents within the bauxite residue. Bauxite residue produced using the Bayer process contains notable scandium. We present new geochemistry, mineralogical, and geological data from the lateritic bauxite and red mud from the active mine and deposit, which aims to investigate the behavior of critical elements during weathering. The geochemical analysis and translated isocon results have shown that the content of scandium in red mud is higher than the average concentration of crustal rocks and is concentrated in the ferrite layer and bauxite residue. A positive correlation between the existence of iron oxyhydroxide mineral in residual iron-rich layer and red muds with the rare earth elements (REE) and scandium concentrations may be interpreted as a scavenging effect of mobile REE. The weathering and leaching processes in bauxite allows the adsorption of the trivalent scandium cation (Sc 3+ ) on goethite and are followed by the ionic substitution with other trivalent cations in the crystal of hematite. The study illustrates the importance of understanding processes during weathering and laterization for geochemical processes and rare earth elements exploration in tropical areas. Thematic collection: This article is part of the Geochemical processes related to mined, milled, or natural metal deposits collection available at: https://www.lyellcollection.org/topic/collections/geochemical-processes-related-to-mined-milled-or-natural-metal-deposits Supplementary material: https://doi.org/10.6084/m9.figshare.c.6689139