Study On Leaching And Extraction Process Of Uranium And Beryllium In A Uranium-beryllium Mine

A large volcanic rock type of uranium–beryllium deposit was recently discovered in Xinjiang.The beryllium reserves in Xinjiang have been proven to exceed 50,000 tons and the associated uranium reserves are also very considerable.U–Be ore in Xinjiang is difficult to recover completely due to the low Be grade,which seriously limits the exploitation and utilization of the ore.With the sustainable development of nuclear power industry and a wide range of applications of beryllium in fields such as metallurgical industry and atomic energy,the demand for beryllium and uranium resources is increasing.It is necessary to develop cost-effective leaching processes to extract uranium and beryllium from low-grade ores.Firstly,according to the different chemical stability of uranium and beryllium in uranium-beryllium ore,the effects of sulfuric acid concentration,leaching temperature,liquid-solid ratio and leaching time on the leaching rate of uranium in the ore were studied.Secondly,the effects of acid-sulfuric acid the leaching rate of beryllium residue after leaching of uranium were studied.Finally,in view of the problem of a small amount of beryllium in the leaching solution after leaching uranium,the selective adsorption of uranium in the leaching solution was carried out by ion exchange resin,and the best leaching agent was selected from four common leaching agents.The specific research results are mainly in the following three aspects:1.Selective leaching of uranium in uranium-beryllium ore.The results show that the leaching rate of uranium was as high as 97.4%and the leaching rate of beryllium was only 1.78%under the condition that the sulfuric acid concentration 0.2M,temperature 348.5K,liquid-solid ratio 4:1 and leaching time 50min.The leaching process of uranium was controlled by the diffusion of the product layer and followed the kinetic model 1-2/3 X-?1-X?^2/3=kt,the apparent activation energy was 5.37kJ/mol.2.The leaching of Beryllium from contain-beryllium residue after leaching uranium.The results show that the leaching rate of beryllium was as high as 97%under the conditions of sulfuric acid bake temperature 220?,sulfuric acid bake time 2 h,leaching solid-liquid ratio1:2,leaching temperature 25?and leaching time 25 min.After sulfuric acid bake under the condition 220?sulfuric acid bake 2h,the surface of the residue changed from relatively dense with a smooth to loose and easily etched by acid,and the occurrence form of beryllium was converted from Be₄[Si₂O₇]?OH?₂ to Na₂Be₂Si₃O₉,which was beneficial to beryllium leaching in the residue.The leaching process of beryllium in residue controlled by the diffusion of product layer and followed the kinetic model of 1-2/3X-?1-X?^2/3=kt,the apparent activation energy was8.96 kJ/mol.3.Selective adsorption of uranium in leaching solution after uranium leaching.The results show that 201×7 anion exchange resin has a good selective adsorption of uranium in the leaching solution,and the separation of uranium and beryllium in the leaching solution can be preliminarily realized.The best leaching agent was 10%H₂SO₄,and the leaching rate of uranium was as high as 99.47%.In this paper,according to the different leaching effects of uranium and beryllium in low acid system,the idea of step-by-step leaching process of uranium-beryllium ore was proposed.After leaching uranium,the residue can be directly leaching beryllium by sulfuric acid bake,which simplifies the technological process.The research in this field undoubtedly provides a new idea for the leaching process of uranium-beryllium ore.