The extraction of Tc(VII), Fe(III), Ru(II), Pd(II) and Mo(VI) from nitric acid solution by bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HBTMPDTP)

With the increase of pH of aqueous phase, the extraction of Tc(VII) by bis( 2,4,4-trimethylpentyl)dithiophosphinic acid (HBTMPDTP) decreases and that o f Fe(III), Mo(VI), Ru(II) and Pd(II) increases. When pH is higher than 3.5 which is suitable for trivalent Am/lanthanides separation by HBTMPDTP extra ction, a very small amount of Tc, > 99% Fe, > 95% Mo, > 80% Ru and similar to 100% Pd are extracted. Fe(III), Mo(VI), Ru(II) and Pd(II) can hardly be stripped from the organic phase by < 0.5 M HNO3 which is used as the stripp ing solution for Am. Fe(III), Mo(VI), Ru(II) and Pd(II) will not contaminat e the Am product to any great extent but affect the recycling of extractant because of their accumulation in the organic phase.