Beneficiation of low-grade Uranium ore from The Atomic Energy Commission (Mark-No.1)

Abstract

The sample, as received, assayed 0.015 percent U3O8 equivalent and gave 60.3 counts/gram/hour with scaler and contained fine-grained quartz-schist slightly feldspathic with magnetite, biotite, hornblende, apatite, epidote and a feebly magnetic black opaque mineral. The minerals that cause radioactivity in the sample are apatite, magnetite, and the feebly magnetic black opaque mineral. Apatite was found to float readily, but not the magnetic minerals. Magnetic separation or tabling is necessary for the concentration of magnetic minerals. Accordingly, a large number of tests employing flotation, tabling and magnetic separation under varying conditions, were employed for the separation and concentration of uraniferous minerals. Straight flotation of the sample (70%-200 mesh) after desliming yielded a refloat concentrate of 58.8 counts (0.061% U3O8 equivalent) with 44.8 percent recovery. Magnetic separation of refloat middling (7.1counts) and primary tailing (1.3 counts) gave magnetic products with 14.0 and 9.7 counts respectively. A concentration of a higher grade (0.104% U3O8 equivalent) can be obtained by tabling the flotation concentration, but the recovery will be very low (16.6%). Magnetic separation at -10 mesh followed by cleaning by tabling and further magnetic separation after grinding to -65 mesh, produced strongly and feebly magnetic table concentrates of 22.5 (0.038% U3O8 equivalent) with recoveries of 27.9 percent and 15.6 percent respectively. Flotation of the non-magnetic product (70%-200 mesh) produced a refloat concentrate of 41.6 counts (0.048% U3O8 equivalent) with a recovery of 12.7 percent, but with the return of refloat middling the recovery is expected to improve to over 30 percent in this product. Further cleaning of the floatation concentrate and mixing it with the other products viz., strongly and feebly magnetic concentrates and slime (22.0 counts, 0.041% U3O8 equivalent), will yield a final concentrate assaying 0.014 percent U3O8 equivalent with an overall recovery of about 90 percent. Although the grade of concentrate produced is 3 to 4 times higher (even 7 times in one case) when compared to the original sample, it still remains a low grade source of uranium.