Beneficiation of Kyanite from Rajkharswan Mines, Bihar

A Kyanite sample from Rajkharswan Mines, Bihar, was received from M/S. Indian Copper Corporation Ltd., Ghatsila, for beneficiation studies .The sample as received assayed 54.9% Al2O3,40.1% SiO2, 0.39% Fe2O3,1.4% TiO2, 0.2% CaO, 0.13%MgO,1.79% K2O+Na2O and 1.13% L.O.I. Flotation employing a 50.5%-200 mesh feed at 4.9 pH and using lactic acid and sodium sulphonate yielded a concentrate assaying 60.4 % Al2O3 with a recovery of 73.5 % Al2O3.Hydroclassification of a 44%-200 mesh feed produced a coarse sand assaying 60.3% with a recovery of 56.4% Al2O3.Flotation of the fine sand yielded a concentrate assaying 60.9%Al2O3 with an additional recovery of 19.5%Al2O3.The combined concentrate from the fine classifier sand ,assayed 60.4% Al2O3 ,0.34 %Fe203 and 1.55 %Ti02 with a recovery of 75.9% Al2O3.Flotation of the fine classifier sand at 8.5 pH employing katha and oleic acid emulsion yielded a concentrate assaying 60.1% Al2O3 which when mixed with the coarse classifier sand yielded a combined concentrate assaying 60.2%AI203 with a total recovery of 74.2% Al2O3.