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.

摘要

加塔尔地区被列为埃及最重要的铀资源之一。在这项工作中，已使用NaNO ₃溶液从含1138 ppm U的Gattar花岗岩矿石中浸出铀。研究和优化了存在和不存在过氧化氢作为氧化剂时硝酸盐的浸出因子。获得的数据表明，在没有氧化剂的情况下铀的浸出只有46％。过氧化物的主要作用是将铁含量氧化为Fe ³⁺，从而将不可浸出的U ⁴⁺氧化为可浸出的U ⁶⁺。基于在15 mmol l ^-1 H ₂ O ₂存在下使用0.005 M NaNO _3的结果最佳浸出条件为在75°C下4/1的液/固比为6 h，铀浸出效率为82.5％。然后使用4％的Alamine 336 /煤油对浸出液进行萃取步骤。Alamine 336从浸出的铀中提取了92.3％。然后将所得溶剂用碳酸盐溶液处理以汽提负载的铀。最后，然后用NaOH处理碳酸盐溶液，以沉淀pH值为11.5的铀。