Solvent Extraction of Pd(CN)_4~(2-) from Alkaline Cyanide Solution with Dodecyl Trimethylammonium Bromide

摘要

The solvent extraction of Pd(CN)_4~(2-) from alkaline cyanide solution by using dodecyltrimethylammonium bromide diluted in benzene was investigated. It has been indicated that Pd(CN)_4~(2-) extraction percentage increases by increasing dodecyltrimethylammonium bromide concentration. Extraction parameters of Pd(CN)_4~(2-), including appropriate diluting agent, dodecyltrimeihylammonium bromide concentration, contact time of aqueous and organic phases, pH of the aqueous solution and organic/aqueous phase ratio, were studied. Octanol has an obvious synergistic effect on Pd(CN)_4~(2-) extraction with dodecyltrimethylammonium bromide. It was indicated that at dodecyltrimethyl ammonium bromide concentration 0.01 mol L~(-1), contact time of 10 min, octanol concentration 40 % (v/v), organic/aqueous phase ratio 1, the optimal pH of the aqueous phasell.5, almost all of the Pd(CN)_4~(2-)(> 99 %) was transferred from the aqueous phase into the organic phase. Ammonium thiocyanate solution could be used as stripping agent. Most of the Pd(CN)_4~(2-) in the organic phase can be stripped w ith aqueous solutions of ammonium thiocyanate.