Extraction and separation of gallium(III) from zinc(II) by 2-carbethoxy-5-hydroxy-1-(4-tolyl)-4-pyridone

Abstract

The extraction of gallium(III) from aqueous hydrochloric, nitric, or perchloric acid solutions by 2-carbethoxy-5-hydroxy-1-(4-tolyl)-4-pyridone (HA) dissolved in chloroform was studied with the aid of 72Ga. From less than 10 −2 M acid concentration gallium is quantitatively extracted; with increasing of the acid concentration the extraction of gallium diminishes and at 3 M acid gallium quantitatively remains in the aqueous phase. The investigation of zinc extraction with 65Zn has shown that zinc does not extract with HA from these acids. On the basis of these differences a fast and simple method for the separation of gallium from zinc is described. Back-extraction of gallium from the organic phase is possible with any of the above-mentioned acids in concentration higher than 3 M. The composition of the gallium(III) extracted species was investigated radiometrically and by characterization of the isolated crystalline compound.