Separation of platinum(IV) and palladium(II) from concentrated hydrochloric acid solutions by mixtures of amines with neutral extractants

• A mixture of Aliquat 336 and TBP was effective for the separation of Pt(IV) and Pd(II).
• Pt(IV) was selectively extracted by this binary mixture at high HCl concentrations.
• Highest separation between Pt(IV) and Pd(II) was obtained at 6 M HCl.
• The McCabe–Thiele diagram showed that most of Pt(IV) can be extracted through three counter-current stages.
• The purity of the stripping solution of Pt(VI) was higher than 99%.

Separation of platinum and palladium from concentrated HCl solutions by extraction with mixture of amines (Aliquat 336/Alamine 336/TOA) and neutral extractants (TBP/TOP/MIBK) have been investigated. The mixture of Aliquat 336 and TBP led to higher Pt(IV) separation factor at 6 M HCl solution. McCabe–Thiele diagram for the extraction of Pt by this mixture was constructed. Low concentration of thiourea in the HCl solution resulted in selective stripping of Pd from the loaded organic. Pt solution with 99.9% purity was obtained by extraction and stripping from the solution containing Pd. A process was proposed to separate the two metals.

Flow sheet of the process for the separation of Pt and Pd from hydrochloric acid solutions by the mixture of Aliquat 336 and TBP.Figure optionsDownload as PowerPoint slide