Kinetics of acid leaching of ilmenite decomposed by KOH

A kinetic study of the leaching of ilmenite paste (resulting from ilmenite treatment by KOH) by sulfuric and oxalic acids has been investigated. The effects of the reaction agitation speed, ilmenite paste particle size, acid concentration, acid/paste mass ratio and temperature on titanium recovery percent from the KOH decomposed ilmenite are reported. The leaching rates are significantly influenced by the reaction temperature and acid concentration. The observed effects of the relevant operating variables on the leaching rates are consistent with a kinetic model for chemical control. The apparent activation energy for the leaching of titanium has been calculated using the Arrhenius expression. The data obtained are compared and discussed with available reported results. Further a flow diagram for production of TiO2 based on KOH decomposition of ilmenite paste-oxalic acid leaching is given.