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 Se-IV and Te-IV, not only from each other, but also from the other accompanying elements. 2,3,5-Triphenyltetrazolium chlor ide has been used as an extractant for the quantitative extraction of Te-IV and Se-IV from bromide and thiocyanate medium, respectively. The formed ion-pair complex of Te-IV and Se-IV can be quantitatively extr acted into a dichloromethane and 1:1 cyclohexanol-toluene solvent mixt ure, 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 solutio n of sodium hypobromite was used for selenium. This separation procedu re in conjunction with the developed methods was applied to an analysi s of the selenium and tellurium content of copper concentrate, inciner ation ash and In-Sb alloy samples.