复盐沉淀法分离络合浸出液中稀土研究

Study on separation of rare earth of complexation leaching solution with double salt precipitation method

以HCl-AlCl3溶液络合浸出包头混合稀土精矿的浸出液为原料,采用硫酸钠复盐沉淀法分离络合浸出液中的稀土。研究络合浸出液酸度、稀土浓度、反应时间、反应温度以及硫酸钠和稀土质量比[m（Na2SO4）：m（REO）]对稀土收率的影响。结果表明：络合浸出液酸度对稀土收率影响较小,当络合浸出液中稀土质量浓度为20 g/L,反应温度为90℃,反应时间为90 min,硫酸钠和稀土质量比为m（Na2SO4）：m（REO）=4：1时,稀土收率达到97.53%。对复盐进行了XRD,SEM-EDS及化学分析,复盐沉淀中主要是NaRE（SO4）2·2H2O和少量CaSO4·H2O的混合物,复盐晶体以棒状形态无规则的堆积在一起,棒状颗粒长度大部分集中在1-2μm,氟与铝基本都进入溶液中。

The raw material was the leaching liquor leached from Baotou Rare Earth concentrate with HCl-AlCl3 solution, and the method of sodium sulfate double salt precipitation was used to separate the rare earth. The effects of complex leaching solution acidity, rare earth concentration, reaction time, reaction temperature and the quality ratio of sodium sulfate to rare earth [m（Na2SO4）：m（REO）] on the recovery of rare earth was studied. The results show that complex leaching solution acidity has little effect on the recovery of rare earth, and when rare earth concentration of complex leaching solution is 20 g/L, reaction temperature is 90 ℃, the reaction time is 90 min, and the mass ratio of sodium sulfate to rare earth is 4：1, the recoveries of rare earth reach 97.53%. The analysis of double salt for XRD, SEM-EDS and chemical constitution indicates that there is the mixture of NaRE（SO4）2·2H2O and CaSO4·H2O in double salt precipitation, the rod-shape crystals double salt is stacked together disorderly, the length of rod-shaped particles is mainly 1-2 μm. Most of the fluorine and aluminum go to the solution, and the quality of the double salt is not affected.