Extraction of Am and rare-earth elements from acidic solutions by alkyl derivatives of dibenzo- and dicyclohexano-18-crown-6

Extraction of rare-earth elements (REE) and Am(III) by various crown ethers on the basis of alkyl derivatives of 18-crown-6 with phenyl- and cyclohexano-fragments from aqueous acid solutions have been studied. The recovery of REE and Am(III) in this system is increased when trichloroacetic acid (TCAA) is used in comparison with pure acid solutions of HNO 3 or HClO 4 . The distribution coefficients of the Ce subgroup in these conditions are higher than those of the elements belonging to the Y subgroup. The composition of extracted complexes of REE (M) with crown ethers (L) were determined as M:L = 1:1 in all cases. The optimal conditions for Am(III)/M(III) separation with a separation factor >50 has been found.