Uranium Extraction from Gattar Granite Sample After Leaching Using Nitrate Solution in Presence of Peroxide

Abstract

The Gattar area is classified as one of the most important Egyptian uranium resources. In this work, the leaching of uranium from Gattar granitic ore containing 1138 ppm U using NaNO3 solution has been applied. The leaching factors of nitrate in the presence and absence of hydrogen peroxide as oxidant were studied and optimized. The obtained data show that uranium leaching in the absence of oxidants was only 46%. The main role of the peroxide is oxidizing the iron content to Fe3+ species, which is responsible for oxidizing the nonleachable U4+ to leachable U6+. Based on the obtained results with 0.005 M NaNO3 in the presence of 15 mmol l−1 H2O2 with a 4/1 liquid/solid ratio at 75°C for 6 h as optimum leaching conditions, the uranium leaching efficiency was 82.5%. The leach liquor was then subjected to an extraction step using 4% Alamine 336/kerosene. Alamine 336 extracted 92.3% from the leached uranium content. The resultant solvent was then treated with a carbonate solution to strip the loaded uranium. Finally, the carbonate solution was then treated with NaOH to precipitate the uranium species at pH 11.5.