Extra acid was added to support the amount to be consumed according to reaction (8). Chemical analyses by Gawu (1997) on the Ichiniso bauxite deposit indicated that the main components were Al2O3, Fe2O3 and SiO2, and that apart from TiO2, most other components were present in trace amounts. Consequently, the H2SO4 content in the leaching solution was set to 1.1 s and 1.2 s according to the reaction (4).