US 4,305,911 AGranted

Non-polluting treatment of uraniferous effluents originating from an alkaline attack of a sulphur-containing uranium ore

AssigneePechiney Ugine Kuhlmann

InventorBernard Berger

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Abstract

A cyclic process for the treatment of a uraniferous liquor containing, in addition to the desired metal, sodium carbonate and/or bicarbonate and sodium sulphate, obtained by the alkaline attack of a sulphur-containing uraniferous ore, the said process comprising fixing the uranium over a first strong anion-exchange resin, eluting it with an ammonium carbonate and/or bicarbonate solution in the form of an ammonium uranyl tricarbonate which is subsequently decomplexed, precipitating and calcinating the precipitated uranates and/or diuranates with regeneration of the eluant solution of ammonium carbonate and/or bicarbonate, passing the liquor which is freed from uranium and leaves the first strong anion-exchange resin into a neutralization zone then over a second anion-exchange resin, eliminating the SO.sub.4.sup..dbd. ions which are subsequently precipitated in calcium form, recycling a carbonate and/or bicarbonated liquor which is free from SO.sub.4.sup..dbd. ions to the attack of the ore, finally regenerating the elution liquor of SO.sub.4.sup..dbd. ions.

Claims16

Dependent claims

A process for the recovery of uranium values from liquor resulting from the attack of sulphur containing uraniferous ores by an alkaline solution of sodium carbonate and/or sodium bicarbonate wherein the resulting liquor contains sodium carbonate and/or bicarbonate and sodium sulphate in addition to uranium values, the steps of

(1) contacting the liquor with an ion exchange resin on which uranium values become fixed, leaving a liquor freed from uranium values while still containing sodium carbonate and/or bicarbonate and sodium sulphate;
(2) eluting the ion exchange resin with a solution of ammonium carbonate and/or bicarbonate to provide an elutant containing the uranium values as ammonium uranyl tricarbonate, ammonium carbonate and/or bicarbonate and ammonium sulphate;
(3) heating the eluant from step (2) to boiling to convert the ammonium uranyl tricarbonate to ammonium uranate and/or diuranate as a precipitate, with the release of NH.sub.3, CO.sub.2 and H.sub.2 O as vapors;
(4) separating the precipitated ammonium uranate and/or diuranate from the liquor remaining in step (3) which still contains ammonium sulphate;
(5) calcining the ammonium uranate and/or diuranate from step (4) to convert the uranate and/or diuranate to uranium oxide UO .sub.3 while giving off vapors of ammonia.

2 more elements

Dependencies are inferred from the claim text.