[en] To achieve trichotomic separation of light lanthanides (Ln), heavy Ln, and Am, batchwise multi-stage extractions using N,N,N',N'-tetraoctyl-diglycolamide (TODGA) extractant from organic acids are studied. This technique has the advantages of both solvent extraction and chromatography, which enable successive separation and management of large volumes of aqueous solutions. Malonic acid (M-Acid) is used as the main component of the aqueous phase. It is clear that the separation factor for Nd/Am from M-Acid and that for La/Am from M-Acid + HNO₃ are both around 30, thus we plan to conduct these separations. (author)