Extractive Separation of Selenium and Tellurium Using 2,3,5-Triphenyltetrazolium Chloride

A simple and selective solvent-extraction method has been devised for the separation of SeIV and TeIV, not only from each other, but also from the other accompanying elements. 2,3,5-Triphenyltetrazolium chloride has been used as an extractant for the quantitative extraction of TeIV and SeIV from bromide and thiocyanate medium, respectively. The formed ion-pair complex of TeIV and SeIV can be quantitatively extracted into a dichloromethane and 1 : 1 cyclohexanol–toluene solvent mixture, respectively. The optimum conditions have been evaluated based on a critical study of the acid concentration, extractant concentration, period of equilibration, effect of dilution and effect of the solvent. Water was used for the stripping of tellurium, while a fresh solution of sodium hypobromite was used for selenium. This separation procedure in conjunction with the developed methods was applied to an analysis of the selenium and tellurium content of copper concentrate, incineration ash and In–Sb alloy samples.