Patent ID: 7754167

Claim:
A method of separating trivalent Americium from trivalent Curium contained in an acidic aqueous solution having at least these cations, and individually recovering the trivalent Americium and the trivalent Curium, which comprises the steps of: (a) contacting the acidic aqueous solution with an acid concentration of 0.01 moles per liter to 1.0 mole per liter with an organic solvent containing a bis(aryl)dithiophosphinic acid of the Formula (4) wherein R 1 and R 2 are each phenyl or naphthyl, unsubstituted or substituted by at least one methyl, ethyl, propyl, isopropyl, cyano, nitro, halo, substituent and with a synergist of the formula (5) wherein X, Y and Z are each R or RO, where R is a branched or unbranched alkyl, to selectively extract from the acidic aqueous solution, the trivalent Americium and the trivalent Curium, leaving behind as a raffinate, the acidic aqueous solution; (b) selectively stripping the trivalent Curium from the organic solvent containing the trivalent Americium and the trivalent Curium with 0.3 molar nitric acid leaving behind the organic solvent containing the trivalent Americium; and (c) stripping the trivalent Americium from the organic solvent with 1.0 molar nitric acid.