Mobil Research and Development Corporation Field Research Laboratory Dallas, Texas
In this paper we present laboratory data on the effectiveness of a fairly severe leaching system ---- sulfuric acid (H2SO4) and an oxidant ---- in recovery of uranium from refractory Crown- point uranium ore. In combination with a strong mineral acid such point uranium ore. In combination with a strong mineral acid such as H2SO4, oxidants such as oxygen or hydrogen peroxide (H202) should be able to degrade the organic matter intimately associated with uranium in slow-leaching uranium ores, thus increasing exposure of the uranium mineral sites to contact by the leachate. Scoping batch leach tests showed that a leachate such as H2SO4 with H2O2 and with ferric ion added gave good racoveries at a fast rate from Crownpoint refractory ore. For detailed study of the H2SO4-oxygen system, a composite core was fabricated with ore segments from several wells in an area In which ore leached slowly with mild leachates. With this system, comprising 0.5% H2SO4, 24.5 gm/liter Na2SO4, 1 gm/liter NaCl and 0.2 gm/liter CO2 with 800 psig (~520 kPa) 02, 65% recovery of uranium was observed rapidly in about 30 pore volumes. This is almost double the recovery observed with a mild leaching system (02-NaHC03) in the same number of pore volumes. Plugging that occurred twice during the leach run appears related to movement of feldspar and quartz fines rather than gypsum deposition.