Anion Exchange Separation of Rare Earths in Methanol‐Nitric Acid Mixed Solutions I. Study on the Distribution Coefficients and Column Elution Method

Abstract

AbstractAnion exchange method for the mutual separation of rare earth was studied in methanol‐nitric acid mixed solutions. For each of rare earth element, the distribution coefficients in different concentrations of nitric acid and also in various compositions of methanol solution were studied with the batch equilibrium method. From these distribution coefficients, elution of rare earth by gradient variation in the compositions of methonal was devised. That is, by keeping constant nitric acid at 2 N acidity and gradiently diluting methanol from its original 80% by volume. Results were satisfactory for the mutual separation of the lighter rare earths, but only fairly for the heavier earths.The secondary metal effect for this anion exchange was also studied in 80% by volume of methanol solution by keeping total concentration of nitrate at 0.8 N. Distribution coefficients were larger than nitric acid with LiNO3 but smaller in the case of NH4NO3 and NaNO3. Despite of these difference in distribution coefficients, no remarkable differences were observed for the separation factors of adjacent pairs.