Beneficiation of Manganese ore Rejects after hand picking from S-G-B-K Mines Gurda, Keonjhar, Orissa

Abstract

A low grade manganese ore from S-G-B-K mines, Gurda in Keonjhar, Orissa assayed Mn, 30.18; MnO2, 39.70 Fe, 16.58; SiO2, 17.72, Al2O3, 4.1; and P,0.03%. Psilomelane was the chief manganese mineral followed by wad and pyrolusite. Ferruginous and siliceous gangue, comprising mainly goethite, hematite, quartz and feldspar, were intimately associated with manganese minerals. Reduction roast and magnetic separation of the reduced ore at 100 mesh, followed by cationic flotation for removal of quartz from the non-magnetic product, yielded a concentrate assaying 57.06% Mn, 6.16% Fe, 10.23% SiO2, 1.65% Al2O3 and 0.032% P., with a Mn recovery of 48.5%. High recoveries can be obtained upto about 55% for a Mn/Fe ratio of 7. The concentrate was suitable for production of standard grade ferromanganese.