Beneficiation of low grade Uranium ore from the Atomic Energy Commission

Abstract

A low grade uranium ore assaying 0.092 percent U3O8 (equivalent) and 0.086 percent Cu, and containing apatite, magnetite, asbestos, chlorite, biotite, quartz, and small amounts of chalcopyrite and pyrite was received from the Atomic Energy Commission for concentration tests. The uranium minerals could not be identified under a Petrological microscope but an auto-radiograph of one of three different radioactive minerals of black, brown, and yellow colours. The uranium minerals in the sample being soft produced a high grade of slime (0.45 percent U3O8 equivalent) in the -10 micron fraction of the sample ground to 25 percent minus 200 mesh, but with a distribution of only 17.0 percent. A uranium recovery of about 48 percent could be collected as slime of 0.20 percent U3 O8 (equivalent) grade. Tabling, magnetic separation, and flotation under varying conditions were performed. A concentrate obtained by straight flotation of ground sample assayed 0.29 percent U3O8 (equivalent) and 0.90 percent Cu, with recoveries of 23.1 percent and 77.7 percent respectively. Magnetic separation of the -28 mesh sample and cleaning of magnetic portion after grinding to -100 mesh followed by flotation of the de-slimed nonmagnetic portion (41.6% -200 mesh), produced a flotation –tailing assaying 0.12 percent U3O8 (equivalent) with 9 percent recovery. If, however, the two slimes and tailing were mixed, a product assaying 0.20 percent U3O8 (equivalent) with a recovery of 58.3 percent uranium , could be obtained which could be improved by another 6 percent by returning one of the products to the circuit. About 22 percent of the uranium in the sample was lost with the magnetite portion assaying 0.052 percent U3O8 (equivalent).