Chemical Grade Bauxite composition offered by us: A12O3 58% (min.), Fe2O3 % (max.) Steel and Cement Industry use. Bauxite should have A12O3 40% SiO2 5% and Fe2O3 30 â 40% bauxite for use in cement industry. In the steel industry metallurgical grade bauxite is used as a flux as partial replacement of fluorspar.