In situ uranium leaching using high pressure CO.sub.2 /O.sub.2 system to overcome chloride ion inhibition
AssigneeMobil Oil Corporation
InventorTsoung-Yuan Yan
Life of this patent
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Abstract
A process is described for improving yield and leaching rates of mineral values in uranium-bearing formations associated with high brine aquifers by using high pressure CO.sub.2 /oxidant in the leaching solution. The high pressure CO.sub.2 overcomes the inhibiting effect of NaCl on the rate of leaching. Uranium is recovered at the well head by ion exchange at a pH of about 4.5 to about 5.0 either under pressure to keep the CO.sub.2 in solution or with provision for CO.sub.2 recovery and recycle.
Claims14
An improved process for the recovery of mineral values from a mineral-bearing subterranean formation, wherein the subterranean formation has a sufficient chloride concentration to substantially inhibit the leaching rate of the mineral values therein, comprising the steps of:
- (a) penetrating the formation with at least one injection well and at least one production well in communication with the injection well;
- (b) introducing into the formation an aqueous leaching solution containing an oxidant and carbon dioxide wherein the carbon dioxide is introduced under sufficient pressure to substantially overcome the inhibiting effect of the chloride ion on the leaching rate;
- and
- (c) producing the aqueous leaching solution containing oxidized and solubilized mineral values.
An improved process for the in situ recovery of uranium values from a uranium-bearing subterranean formation, having formation fluids with a sufficient chloride concentration to substantially inhibit the leaching rate of the uranium value therein, comprising the steps of:
- (a) penetrating the formation with at least one injection well and at least one production well in communication with the injection well;
- (b) introducing into the formation an aqueous leaching solution containing an oxidant and carbon dioxide wherein the carbon dioxide is introduced under sufficient pressure to substantially improve the uranium-leaching rate and to give the formation fluids a pH of from about 4.0 to about 5.0;
- (c) producing pregnant leaching solution containing uranium values and having a pH of from about 4.0 to about 5.0;
- and
- (d) passing the produced pregnant leaching solution through an ion exchange resin to recover uranium values therefrom.
Dependencies are inferred from the claim text.