PROCESS FOR EXTRACTING URANIUM FROM ITS ORES BY USING ALKALINE EARTH CARBONATES AND BICARBONATES SOLUTIONS IN THE PRESENCE OF CARBON DIOXIDE

摘要

PROCESS FOR EXTRACTING URANIUM FROM ITS ORES WITH ALKALINE EARTH CARBONATE AND BICARBONATE SOLUTIONS IN THE PRESENCE OF CARBON DIOXIDE Uranium is extracted from its ores, whether the ores are still in underground deposits or removed therefrom by oxidizing the uranium to a valency of 6 by means of oxygenated water or oxygen in the presence of carbon dioxide, dissolving the uranium by means of alkaline earth carbonate and bicarbonate lixiviant solutions in the presence of carbon dioxide under a pressure below 60 bars and at a temperature of from O tc 100.degree.C, then separating the insoluble substances from the lixiviant after expansion to 4 bars or less to produce a calcium uranyl carbonate liquor. Uranium is recovered from this Iiquor after expansion under vacuum by either: (a) a limewash treatment at a pH of 8 to 9 which precipitates calcium carbonate and separating a liquid fraction which is treated in turn with a limewash at a pH of 10 to 12 and allows the calcium uranate to be deposited, or (b) separation of the calcium carbonate resulting from the ex?ansion and subjecting the liquor to a limewash treatment at a pH of 10 to 12 to form a mixture of calcium uranate and calcium carbonate. After atmospheric expansion and separation of the calcium carbonate resulting from this expansion, the liquor may be treated with hydrogen peroxide to precipitate uranium peroxide or it may be passed over a bed of anionic resins to fix the uranyl carbonate ions.