An Alternative Procedure for Selective Leaching of Uranium from Carbonate-Rich Black Shale, Um-Bogma Formation, El-Allouga, Southwestern Sinai

An alternative procedure was developed for selective leaching of uranium from carbonate-rich black shale of southwestern Sinai (0.16% U3O8). Uranium was present in the rock sample in the hexavalent state. This method is based on using a mixed citric acid/calcium citrate reagent so as to leave the carbonate, vanadium, and copper almost intact for the later processing. The influence of the concentration of citric acid/Ca citrate, molar ratio, grain size, pH of the leach liquor solutions, solid-to-liquid ratio, leaching time, and temperature was investigated in order to find optimum conditions. From the leach liquor, uranium can be recovered by addition of isopropyl alcohol.