Beneficiation of low grade Manganese ore from Sambalpur, Orissa

Abstract

A low grade manganese ore received for beneficiation tests from Rairakhol mines in Sambalpur, Orissa, assayed Mn 38.53; MnO2 52.20; Fe 17.5; SiO2 3.83; Al2O3 5.02; BaO 4.03; and P 0.35 percent. The principal manganese minerals present in the ore were psilomelane, pyrolusite and braunite. Magnetite, hydrated oxides of iron, hematite, quartz and garnet constituted the gangue. Straight magnetic separation of the sample as received as well as at -35 mesh size did not yield satisfactory grades of manganese concentrates. Reduction roast of original sample followed by magnetic separation at different sizes produced manganese concentrates assaying 53.0, 55.2 and 54.0% Mn with manganese recoveries of 71.0, 81.0 and 82.0% at -10, -35 and -65 mesh sizes respectively, for a Mn/Fe ratio of 7 to 1. But the P in the concentrates was high, about 0.34%. Fatty acid flotation was not successful in producing a low phosphorous manganese concentrate.