アミン抽出剤による塩酸水溶液からのイリジウム(III)の溶媒抽出

抄録

Ir(III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in chloride solutions, the formation of IrCl_6–n(H₂O)_n^(3–n)– (n = 0–6). Therefore, it is difficult to extract Ir(III) by solvent extraction, and currently Ir(III) is extracted by oxidizing to Ir(IV), which could form the extraction-active chloride complexes.

In this study, extraction of Ir(III) from hydrochloric acid solutions with 2-ethylhexylamine (EHA) and octylamine (OA) as primary amines, dibutylamine (DBA) as secondary amine and tri-n-octylamine (TNOA) as tertiary amine, were tested to clarify the extraction and the stripping of Ir(III). As a result, the extraction efficiencies of Ir(III) with EHA and OA were high, meanwhile, the extraction efficiencies of Ir(III) with DBA and TNOA were significantly lower than those with EHA and OA. Moreover, the extraction efficiencies of Ir(III) with EHA and TNOA were hardly improved by addition of Sn(II). It was also found that Ir(III) could be easily stripped from EHA with sodium sulfate solutions.