Ammonium Carbonate Pressure Leaching OF Uranium Ores

WITH the development of uranium ores that contain substantial amounts of acid-consuming compounds, the alkaline leach has become an attractive method for extraction. Considerable work has been done on both atmospheric and pressure-leaching with aqueous solutions of sodium carbonate and sodium bicarbonate as the lixiviants.1,2,3 For the treatment of uranium-bearing limestones and other high-lime (CaO) ores, the sodium carbonate leach has proven attractive because it avoids the high reagent consumption incurred by the reaction of sulfuric acid with lime. In addition, the corrosion problems with sodium carbonate are negligible as compared with those encountered in the acid-leach system. The sodium carbonate leach, however, does not yield as high an extraction of the uranium as the acid leach and is not attractive for economic reasons when treating ores that are high in sulfates or sulfides.