Process for the separation of zirconium and hafnium

摘要

Zirconium and hafnium are separated by distribution of the oxychlorides between an aqueous chloride ion-containing solution and a liquid halogenated hydrocarbon containing a dissolved organic amine. The process may be continuous or discontinuous and may be repeated several times. The zirconium predominantly goes into the organic phase and the hafnium predominantly remains in the aqueous phase. The aqueous phase may be a 2 N to 13 N solution of hydrochloric acid, and the chloride ion concentration may be increased by the addition of an alkali metal chloride or an alkaline earth metal chloride. In examples zirconium oxychloride (zirconyl chloride) containing small amounts of hafnium, and hafnium oxychloride containing a small amount of zirconium, are dissolved in hydrochloric acid solutions and contacted with organic solutions of amines in which the solvents are chloroform, bromoform, 1,1,2,2-tetrachloroethane, methylene chloride, o-dichlorobenzene, a mixture of 1,2,3- and 1,2,4-trichlorobenzene, chlorobenzene, bromobenzene, benzyl chloride, 1,2-dibromoethane and 1,2,3-trichloroisobutane, and the amines are tribenzylamine, tri-n-butylamine, tri-n-octylamine and di-n-butylamine; in one case the hydrochloric acid solution contained lithium chloride. The zirconium in the organic phase is recovered by shaking with an aqueous solution of hydrochloric acid. Zirconium dioxide and hafnium dioxide are obtained from the aqueous solutions by precipitation with ammonia and calcination of the precipitates.