Phase Transformation of Minerals in Bauxite

Bauxite comprises five major elements viz. Al2O3, SiO2, Fe2O2, TiO2 and LOI. Major aluminium bearing mineral phase present in the bauxite are gibbsite, boehmite and diaspore however however Iron minerals are mainly in the form of alumo-goethite, hematite and some accessory minerals like magnetite, Illmenite etc. The alumo goethite and hematite are structurally and characteristically different from each other. In general, Indian bauxite contains alumo-goethite is a dominant mineral as compared to hematite. In the beneficiation of bauxite process, an iron mineral plays an important role in magnetic separation study. Hema-tite being a paramagnetic mineral gets easily separated via magnetic separation process while alumo-goethite is feebly magnetic in nature and requires high intensity.