Abstract: A method is disclosed for separating trivalent americium from trivalent curium, coming from an aqueous solution containing at least these cations, wherein, at an acid concentration of 0.01 mol/l-0.3 mogl/l, the aqueous solution is brought into contact with an organic solvent containing a bis(aryl)dithiophosphinic acid having the formula (4) where R1=phenyl or naphthyl R2=phenyl or naphthyl, and radicals of R1 and R2 substituted by at least one methyl, ethyl, propyl, isopropyl-, cyano, nitro, or halo substituent, and containing a synergist having the formula (5) where X and/or Y and/or Z is R or RO, wherein R is branched or unbranched alkyl.

Abstract: The invention relates to a method for separating trivalent americium from trivalent curium. According to the inventive method, an aqueous solution containing at least said cations is contacted, at an acid concentration of 0.01 mol/L to 1 mol/L, with an organic solvent containing a bis(aryl)dithiophosphinic acid of general formula (4), wherein R1=phenyl- or naphthyl, R2=phenyl- or naphthyl, with methyl-, ethyl-, propyl-, isopropyl-, cyano-, nitro-, halogenyl-(Cl?, F?, Br?, J?) substituted radicals of R1 and R2, R1 and R2 being optionally substituted by at least one component from the group comprising methyl-, ethyl-, propyl-, isopropyl-, cyano-, nitro-, halogenyl-(Cl?, F?, Br?, J?), and with a synergist of general formula (5), wherein X and/or Y and/or Z=RO (=alkoxy) or R (=alkyl), R being optionally branched and/or unbranched. The separation factor for americium (III) and curium (III) has an order of magnitude of 10.

Abstract: The invention relates to a method of separating trivalent actinides from at least one trivalent lanthanide and/or yttrium, whereby the trivalent actinides are extracted from an aqueous solution containing a H+ concentration of 0.01 to 2 moles/liter by using as extractant an (aryl)dithiophosphinic acid of the Formula R1R2PS (SH), in which R1 is phenyl or naphthyl, R2 is phenyl or naphthyl, or R1 and R2 are each phenyl or naphthyl substituted by methyl, ethyl, propyl, isopropyl, cyano, nitro, or halogen, with addition of an extraction synergist selected from the group consisting of trioctylphosphate, tris-(2-propylpentyl)-phosphate, and tris-(2-ethylhexyl)-phosphate. The use of the synergist in the extraction allows for a more selective extraction.

Abstract: Trivalent actinides can be separated from trivalent lanthanides in aqueous solutions at H.sup.+ concentrations of 2 mol/l to 0.001 mol/liter by extraction with bis(aryl)dithiophosphinic acid and a synergist such as TBP, TOPO and TBPO in an organic solvent. A high separation efficiency results. The method is applicable to high-level liquid waste from reactors and nuclear-material processing plants.