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. -
PubMed: 18968825 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.