Ternary Complex Formation and Extraction Modeling in Malonate-Buffered Trivalent Actinide-Lanthanide Separations.

The formation of an aqueous ternary complex was investigated in the malonate-based Advanced TALSPEAK system by solvent extraction and optical spectroscopy. Features of the spectroscopy confirmed the presence of a ternary complex between malonate, HEDTA, and the trivalent americium or lanthanide ion. The ternary complex was then incorporated into a solvent extraction model to refine stability constants under Advanced TALSPEAK conditions.