Abstract

Leaching of uranium and REEs with oxalic acid from the Egyptian Abu-Tartur phosphate rock (PR) was studied. The effect exerted on the leaching process by oxalic acid concentration, agitation time, solid to liquid ratio, and leaching temperature was determined. The leaching kinetics of uranium and REEs were evaluated by the shrinking core model. The uranium and REEs leaching kinetics is controlled by diffusion through the fluid film. The activation energy is 5.9 kJ/mol for U and 5.3 kJ/mol for REEs. Equations describing the leaching kinetics were obtained. The optimum conditions are oxalic acid concentration of 0.5 M, agitation time of 2 h, solid to liquid ratio of 1/4, and temperature of 70°C. Under these conditions, the degree of leaching of uranium and REEs reached 92 and 81%, respectively.

中文翻译：

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埃及西部沙漠阿布-塔图尔磷酸盐岩中草酸浸出铀和稀土元素的热力学和动力学研究

摘要

研究了草酸对埃及阿布-塔图尔磷酸盐岩（PR）的铀和稀土元素的浸出。确定了草酸浓度，搅拌时间，固液比和浸出温度对浸出过程的影响。通过收缩核模型评估了铀和稀土元素的浸出动力学。铀和稀土元素的浸出动力学受流体膜中扩散的控制。U的活化能为5.9 kJ / mol，REE的活化能为5.3 kJ / mol。获得描述沥滤动力学的方程式。最佳条件为草酸浓度为0.5 M，搅拌时间为2 h，固液比为1/4，温度为70°C。在这些条件下，铀和稀土元素的浸出率分别达到92％和81％。