Some Recent Results in the Separation Of Metal Chlorides by Solvent Extraction

Abstract

Abstract Solvent extraction is used to selectively separate an aqueous mixture of metal chlorides (Fe, Al and Ti) that is the product from the high-temperature chlorination of fly ash by the HiChlor process. Tertiary amines dissolved in xylene or kerosine are used to separate the Fe from the Al and Ti. Prior to extraction, the organic solution is contacted with HCl to convert the amine to the chloride salt. Data on the effects of organic-to-aqueous ratio, Fe, Al and Ti loadings, and HCl concentration in the aqueous phase are reported. Iron is stripped from the loaded organic phase using dilute HCl. The raffinate is subjected to sparge crystallization with HCl to recover AlCl3.6H2O. The recovery of Ti from the aqueous phase after Fe removal requires the use of tributyl phosphate (TBP) in kerosine for the organic phase, and of higher acid concentrations. Decanol is used as a modifier to prevent formation of a third phase.