Separation of aluminum from rare earth by solvent extraction with4-octyloxybenzoic acid

Abstract

Leaching method is usually used to extract rare earth (RE) elements from ion adsorbed RE ores. In the leaching process, some impurities such as aluminum (Al) enter the leaching solution. The separation of Al from RE by carboxylic acid extractant 4-octyloxybenzoic acid (POOA) was studied in this article. By changing the pH value, temperature, solvent, saponification degree and other parameters, the extraction and separation performance of POOA in chloride system was systematically studied. Through specific extraction experiments and slope analysis, it can be seen that the stoichiometric ratio of POOA to Al is 3:1 during the extraction process. The separation factor of Al3+ and Pr3+ can reach about 160.00. Compared with easily emulsified naphthenic acid, POOA achieves better phase separation. The above results show that saponified POOA (S-POOA) has a good separation effect on Al and RE. Under the condition of low concentration stripping acid of 0.60 mol/L HCl, the developed extraction system can be almost completely stripped, and the stripping rate reaches 97.52%. The regenerated POOA can be directly used for the recycling extraction.