Ruan Zheng, Li Mei, Gao Kai, Zhang Dongliang, Huang Lan, Xu Wei, Liu Xingyu
Key Laboratory of Green Extraction and Efficient Utilization of Light Rare Earth Resources and Mining Research Institute, Inner Mongolia University of Science and Technology, Baotou 014010, China.
School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
ACS Omega. 2019 Jun 4;4(6):9813-9822. doi: 10.1021/acsomega.9b01141. eCollection 2019 Jun 30.
The effects of particle size, temperature, and leaching time on the leaching behavior of rare-earth elements were studied. The leaching efficiency of the rare earth reached 39.24% under leaching conditions of hydrochloric acid concentration of 8.00 mol/L, particle size 95% distributed below 1.5 μm, leaching time of 120 min, and temperature of 90 °C. According to the scanning electron microscopy and X-ray diffraction analysis of the residue, the mechanism of the leaching process was also investigated. Actually, the phase of REFCO transformed into that of RECl and REF but there was an existing intermediate transition, where the phase of REFCO on reacting with hydrochloric acid generated that of REO F and this process also released RE into the solution. REO F continued reacting with hydrochloric acid to release a lot of F, which on combining with RE formed REF precipitation. The leaching kinetics of rare earths follows a shrinking core model that can be expressed as 1 - 3(1 - ) + 2(1 - ) = . The activation energies are 62.1, 54.8, 35.1, and 34.9 kJ/mol, respectively.
研究了粒度、温度和浸出时间对稀土元素浸出行为的影响。在盐酸浓度为8.00 mol/L、粒度95%分布在1.5μm以下、浸出时间为120 min、温度为90℃的浸出条件下，稀土浸出率达到39.24%。通过对残渣的扫描电子显微镜和X射线衍射分析，对浸出过程的机理进行了研究。实际上，REFCO相转变为RECl和REF相，但存在一个中间过渡过程，即REFCO相与盐酸反应生成REO F相，该过程也将RE释放到溶液中。REO F继续与盐酸反应释放出大量的F，F与RE结合形成REF沉淀。稀土的浸出动力学遵循收缩核模型，可表示为1 - 3(1 - ) + 2(1 - ) = 。活化能分别为62.1、54.8、35.1和34.9 kJ/mol。
