Extraction of silver and mercury with tetraphenyl imidothiodiphosphate

Abstract

The extraction of complexes of silver and mercury with tetraphenyl imidothiodiphosphate (HA) from HNO 3 and HCl solutions, respectively, into benzene was studied. The extraction from dilute aqueous solutions establishes within 10 min. The composition and stability of the complexes extracted, AgA(HA) and HgA 2 , were derived from the dependences of the distribution ratios of the respective metals on the acidity of the aqueous phase and analytical concentration of reagent. Using HClO 4 solutions as the aqueous phase, silver is extracted by a double extraction mechanism, an appreciable fraction of the metal passing into benzene also in the absence of HA. Based on the distribution of HA between the aqueous phase and benzene, its distribution and dimerization constants were established; the dissociation constant of the reagent was determined potentiometrically.