Dihexyl sulfideによる塩酸溶液からのPd (II)およびPt (IV)の抽出とSulfideの劣化について

Abstract

Extraction of Pd(II) and Pt(IV) with dihexyl sulfide (DHS) from chloride solutions, and the degradation of DHS to dihexyl sulfoxide (DHSO) were investigated in this study. When Pt(IV) exists in aqueous solution to be extracted, the extraction of small amounts of Pt(IV) causes the oxidation of DHS to DHSO as well as the reduction of Pt(IV) to Pt(II). The presence of DHSO in organic phase results in the formation of insoluble substances with metals ions such as Sn(IV), Fe(III), Si(VI), Zn(II) and Pt(IV) at the interface between the organic and aqueous phases. The appearance of the insoluble substances is due to the low solubility both in aqueous and organic phases. The insoluble substance is decreased by the addition of the modifier like alcohols. In the extraction of metal ions, the repeated operation of extraction and stripping of metal ions with DHS increases the amount of DHSO. The extraction of Pt(IV) is increased, when the contact time is extended and when the concentration of Pd(II) is lower in the extraction operation of Pd(II) and Pt(IV) by DHS. It is considered that the oxidation of DHS takes place by the following reaction. H2PtCl6 + 3DHSorg + H2O →PtCl 2·(DHS)2, org + DHSOorg + 4HCl