Solvent Extraction of Iridium(IV) with the Petroleum Sulfoxide

Abstract

The petroleum sulfoxide was used in the extraction of iridium(IV) from hydrochloric acid solution. Iridium(IV) was extracted quantitatively with petroleum sulfoxide in xylene. Sodium hydroxide solution could be used as stripping agent. Extraction parameters of Ir(IV), including petroleum sulfoxide concentration, contact time of aqueous and organic phases, organic/aqueous (O/A) phase ratio, hydrochloric acid concentration and sodium hydroxide concentration of aqueous phase, were studied in detail. In order to find an optimum condition to separate iridium and rhodium, solvent extraction experiments were performed from chloride solution by using petroleum sulfoxide as an extractant. A new process for the extraction of iridium by petroleum sulfoxide was developed. Based on this process, Ir(IV) can be extracted from a mixed chloride solution containing a large amount of Rh(III) and less amount of Ir(IV).