Extraction of rhodium from other platinum group metals with Kelex 100 from chloride media containing tin

• Published in: Hydrometallurgy 1997-10, Vol.46 (3), p.373-382
• Main Authors: Shafiqul Alam, M., Inoue, Katsutoshi
• Format: Article
• Language: English
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/S0304-386X(97)00019-4

Solvent extraction of platinum group metals such as: Pd, Pt and Rh was carried out from chloride media with Kelex 100 in the absence and presence of a large amount of tin. When tin is absent in the feed solution, the order of extraction was found to be: Pd > Pt > Rh (at low acidity) and Pt > Pd > Rh (at high acidity). On the other hand, when a large amount of tin is present, the order becomes: Rh > Pd ≈ Pt (at low acidity) and Rh > Pt > Pd (at high acidity). It was found that addition of a large amount of tin in the feed solution increases the Rh extraction and decreases the Pd and Pt extraction, which makes it possible to separate Rh selectively from their mixed solution. Stripping of rhodium from the loaded organic solution containing tin can be greatly enhanced by adding some oxidizing agent to the stripping agent. Stripping increases with the increase in the concentration of the oxidizing agent and the order of the stripping ability of the oxidizing agents employed in this work was found to be: HNO 3 > KMnO 4 > H 2O 2.