THE EXTRACTION OF SOME BASE-METAL IONS BY CYANEX-301, CYANEX-302 AND THEIR BINARY EXTRACTANT MIXTURES WITH ALIQUOT-336

The extraction behaviour of Cyanex 301, Cyanex 302 and their binary extractant mixtures with Aliquat 336 towards copper(II), zinc(II), iron(III), iron(II), cobalt(II), nickel(II) and manganese(II) is indicated. The extraction data were collected from sulphate solutions with acidities ranging from pH 10 to 8 mol/dm3 sulphuric acid. Cyanex 301 is a more efficient extractant than Cyanex 302 and is able to effect extraction at greater acidities. In combination with the organic base Aliquat 336 the extraction power of these extractants is lowered and in some cases the extraction is suppressed appreciably. However, the suppression of extraction can be useful in metal separation and affords greater control over the back-extraction. The suppression is ascribed to the high stability of the acid-base couple which must dissociate in order to effect extraction.