混合稀土料液中环烷酸萃取分离稀土和铝的研究

Study on Extraction Separation of Aluminum and Rare Earth Mixture in Cycloalkane Acid System

在环烷酸体系中,对不同混合轻稀土料液酸度、铝浓度和萃取剂皂化值条件下,一定配比混合稀土和铝的分配比D、分离系数β进行研究。结果表明,混合稀土料液酸度pH=0.5时,DAl=16,DRE=0.0448,βAl/RE=356.9;当料液中Al2O3浓度为0.17~0.32g/L时,氧化铝的分配比DAl>1,βAl/RE有较大值;皂化度为0.3mol/L时,不仅能够避免由过皂化引起的乳化发生,同时稀土和铝还有较好的分离效果。因此高酸度、低浓度铝和低皂化度的环烷酸体系可以获得铝和混合稀土更好的分离效果和较高的分离系数。在最优工艺条件下进行稀土和铝分离萃取试验,有机相和水相较易分层,萃取反应界面基本无三相,分相极为理想,余液中铝含量小于0.011%,满足工业生产对铝含量的要求。

Distribution ratio(D)and separation coefficient(β)of mixed rare earth and aluminum in naphthenic acid system were studied under different acidity of mixed light rare earth materials,aluminum concentration and different saponification values of extractant.The results show that when pH value of the mixed rare earth solution is 0.5,DAl=16,DRE=0.0448,andβAl/RE=356.9;when Al2O3 concentration in solution is 0.17~0.32g/L,DAl>1,andβAl/RE exist biger value;when degree of saponification is 0.3mol/L,not only emulsification caused by oversaponification can be avoided,but also rare earth and aluminum have better separation effect.Therefore,separation effect and higher separation factor of aluminum and mixed rare earth can be obtained in naphthenic acid system with high acidity,low aluminum concentration and low degree of saponification.Organic phase and aqueous phase are easier to stratify,and extraction reaction interface is basically free of three phases under the optimum separation and extraction experiments conditions.Aluminum content in remaining liquid is less than 0.011%,which satisfies requirements for aluminum content in industrial production.