Abstract:
Partially laterised Khondalite (PLK) refers to the waste material produced during the mining of bauxite ore. The PLK sample contains 39.6% Al2O3, 21.30% Fe2O3, 27.45% SiO2, and 1.1% TiO2. This study presents a novel method for reducing the iron (Fe) content to less than 2%, suitable for refractory industrial applications through various physical and chemical beneficiation techniques. The characterisation of the PLK feed sample was carried out using X-ray diffraction (XRD), and it shows that kaolinite and gibbsite are the major phases and hematite, ilmenite, and quartz are the minor phases. Since the physical beneficiation process (composite non-magnetic product) only achieved limited iron removal (5.24%), the hydrochloric acid (HCl) leaching process was adopted. The optimal leaching conditions for reducing iron to below 2% were found to be 80˚C, 6 molar concentration, 15% pulp density, and 3 hrs of leaching. Kinetic analysis, based on the initial rate method, indicated a first-order reaction mechanism, with the leaching process being reaction-controlled and an activation energy (Ea) of 42.76 kJ/mol.
