Studies for Ultimate Uranium Separation from Its Low-Content Carbonate Leachate Solutions by Ion Flotation

Abstract

The research is aimed at removing uranium from low uranium content solutions using the ion flotation technique. The ion flotation process is an excellent technique for uranium separation from its solutions with low content or trace levels of uranium after optimizing carbonate–bicarbonate concentration for such solutions. It can also be applied to collecting uranium efficiently from all raffinates of the uranium separation or purification projects involving low-grade ore instead of other conventional long tedious methods such as ion exchange or solvent extraction, especially at low U levels. In this study, cetyltrimethylammonium bromide was used as a collector. The factors that can affect the flotation process (uranium concentration, gas flow rate, concentration of collector, and flotation time) were studied, and the best conditions were chosen: uranium concentration 0.02 g/L, carbonate concentration 10 g/L, gas flow rate 52 cm³/min, collector concentration 5 × 10^–4 M, ethanol concentration 0.2% v/v, and flotation time 40 min. Under these conditions, the uranium flotation percentage reached more than 99%. A sample representing a sandy carbonaceous rock of Allouga area, southwestern Sinai, was prepared for alkaline leaching of uranium because of the high content of the carbonate which will consume large amounts of acids. The results of the experiments have shown that the optimum Na₂CO₃/NaHCO₃ ratio is 1/1 at a total concentration of 80 g/L and S/L = 1/2, with 4-h agitation at room temperature. Under these conditions, the uranium leaching efficiency reached 94.2%, and the leachability increased to 98.7% at 80°C. The produced carbonate alkaline uranium-bearing leachate was subjected to the flotation process. A simplified sketch for the uranium separation from the carbonate solutions with a cationic collector is presented.