title: Selective extraction of gold(III) in the presence of Pd(II) and Pt(IV) by salting-out of the mixture of 2-propanol and water.
abstract: The mixture of 2-propanol with water has been employed to extract Au(III) along with other precious metals such as Pd(II) and Pt(IV) by using NaCl in the concentration range of 2.5-4.0 mol dm(-3). Upon the addition of NaCl within this concentration range (2.5-4.0 mol dm(-3)) phase separation was attained. Gold(III) in aqueous phase was quantitatively extracted into the 2-propanol phase at 2.5-4.0 mol dm(-3) of NaCl. The extraction of the other metals such as Pd(II) and Pt(IV) was much lower than for that of Au(III). Thus a maximal selective separation of Au(III) from these metals could be attained using the mixture of 2-propanol with water. A reaction mechanism involving the ion-pair of Na(+) and [AuCl(4)](-) has been proposed to explain this extraction.
authors.affiliation: Department of Chemistry, Faculty of Science and Engineering, Saga University, 1-Honjo-machi, Saga 840-8502, Japan.
authors.forename: Nguyen Huu
authors.initials: NH
authors.lastname: Chung
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tabata