Solvent extraction of silver(I) from nitrate media using thiourea derivatives

Liquid-liquid extraction of Ag(I) from nitrate solutions using N-(N',N'-die thyl thiocarbamoyl)-N'-phenylbenzamidine (TCBA) and 1-6,-diethylcarbamoyl i mino-1,6-diphenyl-2,5 dithiahexane (TCTH) dissolved in cumene has been stud ied. The extraction of Ag(I) from 1moldm(-3) NO3- solutions by TCTH and TCB A was investigated as a function of several variables: equilibration time, organic phase diluent, pH of aqueous phase, Ag(I) and NO3- concentration in aqueous phase as well as TCBA and TCTH concentrations. Experimental equili brium data were analysed numerically using the programs LETAGROP-DISTR and LETAPL and the results showed that Ag(I) extraction could be explained assu ming the formation of AgL and AgNO3HL with TCBA (HL) and AgNO3S with TCTH ( S). The metal extraction was not influenced significantly by the structures of the thiourea derivatives used as extractants. The back extraction of Ag (I) from loaded organic phase was performed using different strippants and 0.5 moldm(-3) NaSCN was found to be efficient for this purpose. (C) 2000 So ciety of Chemical Industry.