Beneficiation of a low grade rock phosphate sample from Dakan Kotra area, Udaipur Dt., Rajasthan

Abstract

A Sample of low-grade rock phosphate from the Dakan-Kotra area, Udaipur Dt., Rajasthan and received from G.S.I. assayed 14.05% P2O5, 6.26% L.O.I. with traces of FeO, Cl & Cu. Collophane was the chief phosphate mineral followed by minor amounts of apatite. The predominant gangue mineral in the sample was calcite followed by quartz. Phosphate was fairly well liberated at about -150 mesh. Primary flotation with a feed containing 95.6% -200 mesh and employing tall oil as collector for phosphate minerals and sodium silicate in combination with Quebracho as depressant for gangue, yielded a rougher float assaying 16.6% P2O5, which after four cleanings produced a refloat concentrate assaying 30.6% P2O5 with a recovery of about 63% P2O5 in it. Flotation tests performed with the calcined sample, after removal of lime in the form of slime, followed by two cleanings yielded a refloat concentrate assaying 34.5% P2O5 with a recovery of 58.6% P2O5 in it was low. This may be due to the high Calcitic content in the sample. Further tests to improve the grade and recovery were not successful.