Flotation studies on a Copper ore sample from Rakha Mines, Bihar” of National Mineral Development Corporation Limited

Abstract

A low grade copper ore from Rakha mines received from National Metallurgical Laboratory Corporation Ltd., assayed 2.73%Cu, 0.072%NI,0.026% Mo,0.02%Co,73.08% SiO2, 5.54% Fe and 3.96% S. The chief copper mineral was chalcopyrite which was well liberated from siliceous gangue at about 100 mesh size. Optimum conditions for rougher flotation of copper were determined by varying feed fineness, pH, further and collectors. Good results were obtained when roughing was done using K.E. Xanthate and Pine oil at a pH of 8.8, with a flotation feed having 54.8% -200 mesh. The float assayed 24.31% Cu and recovered 96.9% Cu in it. Since the copper minerals exhibited natural floatability, use of pine oil alone was sufficient to float the copper minerals and Xanthate addition was necessary only during the last stage of flotation. The rougher float obtained under these conditions assayed 24.25% Cu with a recovery of 97.9% Cu. Reflotation of the rougher float after grinding to -150 mesh size yielded a refloat Cu concentrate assaying 30.1% Cu with a recovery of 91.0% on in it. A Mo concentrate assaying 35.9% Mo (60.0% MoS2) and with a recovery in the product of 68.4% Mo was obtained as a valuable bye-product from the Cu concentrate by the use of departments for Chalcopyrite . It is expected that further cleanings of the Mo float and return of the middling products to the circuit would improve the results further. Results of (i) grindability tests with the ore, (ii) settling and (iii) filtration studies with the tailing and concentrate are presented.