Study on the Separation of Lanthanum and Non-rare Earth Impurities by CL-P507 Resin

The traditional process of producing rare earth products contains a considerable quantity of non-rare earth impurities, which seriously restricts the application of high-end rare earth products. In this study, the dynamic adsorption-desorption experiments of single and mixed ions were studied by CL-P507 resin with La as an example, this was done to elucidate the adsorption behavior and separation mechanism of impurity ions in rare earth feed soluting and the adsorption mechanism was analyzed by the slope method. The results show that the dynamic molar adsorption capacity of P507 extraction resin for a single ion is in the order of Zn>Fe>Al>La>Ca>Cr at 25 ℃, using HCl solution as desorbent, the corresponding desorption concentrations are 0.10 mol/L, 3.00 mol/L, 2.50 mol/L, 0.15 mol/L, 0.05 mol/L, and 1.50 mol/L, respectively. The adsorption-desorption experiments of non-rare earth impurities in the mixed feed solution were carried out, the results show Fe and Zn are preferentially adsorbed, Ca and Cr are basically not adsorbed, the order of desorption for different ions is La≈Zn>Al>Fe, La and Zn show a co-adsorption and co-desorption law. The column adsorption-desorption experiments can be used to deeply separate Ca, Al, Fe, Cr and La, while Zn and La are difficult to achieve efficient separation. In addition, the slope method indicates that for 1.0 mol La³⁺ adsorbed, 2.0 mol H⁺ are simultaneously released, and 1.5 mol for Zn²⁺.