Removal of aluminum from chloride leach solutions of rare earths using 3-((bis(2-ethylhexyloxy))phosphoryl)-3-phenylpropanoic acid (PPPA)

The extraction and separation of Al3+ from a chloride solution of rare earths was studied using 3-((bis(2-ethylhexyloxy))phosphoryl)-3-phenylpropanoic acid (PPPA) as the extractant. The effects of factors such as initial pH value (pH(ini)), temperature and saponification degree were investigated. The extraction is a cation exchange process deduced by the slope analysis method. Increasing the temperature facilitates the separation of aluminum from rare earths. Stripping of the loaded Al-3+ can be achieved by mineral acid solutions of concentrations of 1.0 mol/L or higher. A cascade extraction process was used to remove Al3+ from a chloride liquor of the concentrate of ion-adsorption type rare earth ore. The Al3+ concentration in the aqueous solution decreased from 304.5 mg/L to 4.35 mg/L, and the recovery of rare earths was 95.6% after 5 stages of extraction and 2 stages of scrubbing.

Automated summary

This study investigated the extraction and separation of Al3+ from a chloride solution of rare earths using PPPA as the extractant. Factors such as pH value, temperature, and saponification degree were found to affect the extraction. Increasing the temperature facilitated the separation of aluminum from rare earths. A cascade extraction process successfully removed Al3+ from a chloride liquor of the rare earth ore, achieving a high recovery rate of rare earths.