Removing aluminum from a low-concentration lixivium of weathered crust elution-deposited rare earth ore with neutralizing hydrolysis

Abstract

Aluminum, the main impurity in the lixivium of weathered crust elution deposited rare earth ore, not only results in an increasing consumption of precipitant in the rare earth precipitation process, but also lowers the purity of final rare earth product. Aluminum in the weathered crust elution-deposited rare earth ore lixivium should be removed. Neutralizing hydrolysis method was employed to remove aluminum from the lixivium. Hexamethylenetetramine was found to be the optimum pH regulator for the removal of aluminum in the low concentration. When used to adjust the pH value of the lixivium to 5.0, aluminum in the lixivium can be effectively removed in the form of aluminum hydroxide precipitation with removal rate of 97.60 %. It shows that hexamethylenetetramine has a good effect on the removing of aluminum ions from the low-concentration lixivium. Moreover, hexamethylenetetramine in removing aluminum from lixivium has little adverse effect on the RE precipitation process.