Separation of Rare Earth and Aluminum by Selective Complexation

The presence of aluminum in the weathering crust leaching rare earth ore harms the subsequent extraction and separation of rare earths. High-quality rare earth production processes must reduce the aluminum content in their feed liquid. Groups containing lone pairs of electrons can form stable insoluble complexes with metal ions under certain conditions. In this paper, 3-hydroxyphenylphosphoryl propionic acid is used to selectively separate rare earths by complexation in feed liquid. The results show that: using 3-hydroxyphenylphosphoryl propionic acid as the complexing agent, and when the amount of 3-hydroxyphenyl phosphoryl propionic acid is six times the theoretical complete reaction amount, the reaction time is 10 min, the reaction temperature is 50 °C, and the solution is adjusted to pH 1, the extraction rate of RE3+ is 90.48%, and the extraction rate of Al3+ is nearly 9.52%. The separation of rare earth and aluminum is well realized. 3-hydroxyphenyl phosphoryl propionic acid has good water solubility and low cost, and the product after complexation reaction with metal ions is solid and easy to separate. It has potential as an alternative complexing agent in the industry.