Beneficiation of low–grade soft Chrome ore from Kittaburu , Singhbhum District, Bihar

Abstract

A low-grade soft chrome ore assaying 36.66% Cr2O3 and 19.05% FeO was received for beneficiation tests. The principal minerals constituting the sample are chromite, chlorite and talc. Jiggling a -14 +48 mesh feed produced a medium grade of concentrate assaying 44.73% Cr2O3 and 19.39% FeO with a recovery of only 25.4% Cr2O3. Jiggling the 14 +48 mesh product followed by tabling of the -48 mesh fraction (including the crushed jig tails) produced a combined jig-table concentrate, assaying 48.3% Cr2O3 and 20.84% FeO with a recovery of 75.9% Cr2O3. Straight tabling a -48 mesh feed yielded a concentrate assaying 51.19% Cr2O3 and 22.35% FeO with a recovery of 75.9% Cr2O3. Straight tabling after grinding to -65 mesh and classification into 2 sizes, produced a combined concentrate assaying 54.1% Cr2O3 and 22.4% FeO with a recovery of 71.6% Cr2O3 .A higher recovery of 82.3% could, be obtained, if a middling product obtained during the tests is mixed with the above concentrate, in which case the grade will be 51.7% Cr2O3. Humphrey’s spiral treatment using a -48 mesh feed yielded a concentrate assaying 50.36% Cr2O3 with a recovery of only 55.5%. Flotation tests under varying conditions showed no separation of chromite from the gangue minerals.