白云鄂博稀土矿绿色浸出工艺研究

针对目前白云鄂博稀土矿处理工艺中放射性钍进入废渣难以存放、Ce(Ⅳ)难以浸出等问题,采用碱分解-硫酸浸出-水浸出处理白云鄂博稀土矿,考察了初始酸度、酸矿比、浸出温度和浸出时间等浸出条件对稀土、钍和Ce(Ⅳ)浸出的影响。结果表明: 在初始硫酸浓度6 mol/L、酸矿质量比 1.1∶1、反应温度90 ℃、反应时间120 min条件下,稀土平均总浸出率为95.5%,Ce(Ⅳ)和钍平均总浸出率均大于98%。Ce(Ⅳ)和钍进入酸浸液中,三价稀土进入水浸液中,实现了Ce(Ⅳ)与三价稀土元素的粗分离,解决了放射渣的问题。

Green Leaching Technology for Bayan Obo Rare Earth Ore

In view of the existing problems in the processing technique for the Bayan Obo rare earth ore, such as difficulty in the storage of waste containing radioactive thorium and difficulty in leaching of Ce(Ⅳ), a process consisting of alkaline decomposition, sulfuric acid leaching and water leaching was adopted in the experiment, and effects of initial acid concentration, acid to mineral ratio, leaching temperature and leaching time on the leaching of rare earth, Ce(Ⅳ) and ThO₂ were explored. It is found that leaching at a temperature of 90 ℃ for 120 min with an initial sulfuric acid concentration of 6 mol/L and acid to mineral ratio of 1.1∶1 resulted in an average leaching rate of rare earth reaching 95.5%, the total leaching rate of Ce(Ⅳ) and ThO₂ more than 98%. This process can realize the crude separation of Ce(Ⅳ) and trivalent rare earth, with Ce(Ⅳ) and ThO₂ pulled into acid leaching solution while rare earth trivalate into water leaching solution, thus solving the problem of radioactive waste.