Characterization and beneficiation studies for the removal of iron from a china clay from India

Abstract

34333A china clay sample from Jharkhand State, India, containing 65.0 wt.% SiO2, 22.7% Al2O3, 1.77% Fe2O3 and 9.10% LOT was subjected to physical beneficiation and acid leaching studies to improve its quality. The clay was characterized by optical microscopy, XRD, and wet chemical analysis methods. Quartz and goethite are the two major impurities. High intensity magnetic separation removed only 10% of the total iron. Experiments with oxalic acid were carried out to establish the leaching kinetics of iron and the effects of acid concentration, time and temperature on iron leaching were also examined. The study demonstrated that similar to 90% of total iron could be removed using 5% oxalic acid. The dissolution of iron from clay is best described by diffusion of ions through the product layer of constant size spherical particles. The activation energy of the leaching process over the temperature range was calculated to be 51.14 kJ/mol.