Beneficiation of Gypsum samples from Jamsar Mines, Rajasthan

Abstract

Four samples of low grade gypsum received from M/s. Bikaner Gypsums Ltd. Bikaner, Rajasthan assayed SO3 32.84, 37.15, 38.55 and 36.56 % with gypsum equivalents of 70.62, 79.87, 82.88 and 78.59% respectively. The gangue minerals in the samples were Quartz, hornblende, calcite and clay in varying proportions. Rejection by screening of the -150 mesh fractions after stage-crushing the samples to -10 mesh, produced concentrates assaying SO3 40.70, 41.8, 40.7 and 41.2% (gypsum equivalents 87.5,89.9,87.5, and 88.6%) with recoveries of 85,83.6,78.9 and 82.3% SO3 respectively. Flotation performed with -150 mesh rejected fractions using sodium oleate yielded concentrates assaying SO3 45.51, 45.55, 45.81 and 45.06% with recoveries of 70.1,83.1,93.5 and 66.3% respectively of the flotation feeds. The +150 mesh fractions met the specifications required for fertilizer production and the flotation concentrates could be used for plaster of Paris. Flotation employing Amine 220 as a collector for quartz and other gangue minerals produced tailing (gypsum concentrate) assaying 44.57% SO3 recovering 85.6% SO3 in the original sample. Treatment of -10 mesh samples in a hydro-classifier produced sand fractions assaying SO3 81.3, 85.6, 80.6 and 82.2% respectively.