Selective extraction of uranium from uranium-beryllium ore by acid leaching

Both uranium and beryllium are very important strategic metals and have been applied to many fields, such as nuclear industries, atomic energy, metallurgical industries and telecommunications industries. When uranium and beryllium in the ore were leached simultaneously, a complicated downstream separation process was needed. Based on the different chemical stabilities of uranium and beryllium, an acid leaching method was employed in this work to selectively extract uranium from uranium-beryllium ore. The effects of sulfuric acid concentration, temperature, liquid-solid ratio and leaching time on the leaching efficiency were studied experimentally. Results indicated that treatment of the ores in 0.2 M sulfuric acid at 348.5 K for 50 min with the solid-liquid ratio of 0.25 g/mL is optimum. Under optimal conditions, the leaching efficiencies of uranium is 97.4% and the leaching efficiencies of beryllium is 1.78%, and the standard deviation of them are less than 2% and 0.06%, respectively. Results of kinetic study suggest that the leaching process of uranium was thermodynamically favorable and was controlled by the diffusion of the product layer, whereas the rate-determining step for beryllium leaching is the surface chemical reaction.