ABSTRACT
Representative samples of bauxite ore from four mines of Khushab, namely, Sultan Mehdi, Chamil More, Niaz Mine and Nadi, operated by Punjab Mineral Development Corporation, were obtained to extract alumina by H2SO4 process. X-Ray Diffraction (XRD) analysis and photomicrographs obtained from thin sections showed that ore samples were mainly boehmite (Al2O3, H2O), kaolinite and quartz. The ore was first calcined at 750°C and then ground to minus 20 mesh for H2SO4 leaching. The leached slurry was then filtered to obtain pregnant solutions of Al2 (SO4)3, which was concentrated and treated with ethanol to remove iron impurities. The results of the filtrate treatment with ethanol were not encouraging after crystallization and calcination at 900°C for samples with low iron contents. Therefore, all the tests for leaching the ore samples were carried out without ethanol. The results indicated that, except Nadi Ore, all other samples from Sultan Mehdi, Chamil More and Niaz Mine showed good response to leaching with sulphuric acids, giving reasonable recoveries of alumina (30.44% to 35.15%).
