Abstract: A method for concentrating and recovering uranium material from a solution containing uranium, comprises passing the solution through at least one semipermeable membrane system capable of concentrating uranium, to provide a uranium rich product.

Abstract: A method is disclosed for restoring a clay rich aquifer which has been solution mined with ammonium ions. Calcium carbonate is precipitated from a solution pumped through the aquifer by the addition of calcium oxide, calcium hydroxide, or a mixture thereof in quantities sufficient to raise the pH to at least about 9.5. The precipitated calcium carbonate is separated from the solution and the ammonium ion is then removed from the solution by standard techniques. The solution is recycled through the aquifer and these steps are repeated until the bicarbonate ion concentration has been reduced to such an extent that the addition of at least one soluble salt of calcium, magnesium, or potassium to the solution does not result in precipitation of calcite underground, plugging the aquifer. Recycling with the addition of the soluble salt is continued until the ammonium ion concentration is reduced to a desired level. Finally, residual amounts of the salt are removed from the aquifer using standard techniques.

Abstract: A metal containing acidic solution, also containing humic acid impurities and contaminants, is purified by contacting the acidic solution with a scrubbing agent consisting essentially of a metal extractant and from about 50 vol.% to about 90 vol.% of a hydrocarbon, where the scrubbing agent interacts with impurities and contaminants in the acidic solution to form a sludge phase which is removed and a purified acid phase which can be fed into a metal recovery process.

Abstract: In uranium recovery by solvent extraction processes, uranium is separated from iron in an organic extract by stripping the extract with a dilute aqueous solution containing carbonate ions, hydroxyl ions, and ammonium or alkali metal ions. The iron precipitates during stripping as Fe.sub.2 O.sub.3.nH.sub.2 O which is filtered off. The uranium is then precipitated from the filtrate as UO.sub.3.2H.sub.2 O by steam stripping or as ammonium diuranate by lowering the pH to about 2 to decompose the carbonate then raising it with ammonia or ammonium hydroxide to about 7.