Column leaching process of rare earth and aluminum from weathered crust elution-deposited rare earth ore with ammonium salts

In order to better understand the leaching process of rare earth (RE) and aluminum (Al) from the weathered crust elution-deposited RE ore, the mass transfer of RE and Al in column leaching was investigated using the chromatographic plate theory. The results show that a higher initial ammonium concentration in a certain range can enhance the mass transfer process. pH of leaching agent in the range of 2 to 8 almost has no effect on the mass transfer efficiency of RE, but plays a positive role in the mass transfer efficiency of Al under strong acidic condition (pH<4). There is an optimum flow rate that makes the highest mass transfer efficiency. The optimum leaching condition of RE is the leaching agent pH of 4-8, ammonium concentration of 0.4 mol/L and flow rate of 0.5 mL/min. The mass transfer efficiencies of RE and Al both follow the order: (NH4)(2)SO4<NH4Cl<NH4NO3, implying the complexing ability of anion.