| A study has been made on the solvent extraction of platinum, one of the platinum group metals, with diluted tri-n-butyl phosphate(TBP). Systems involving hydrochloric acid as extract-promoting agent have been studied in the distribution of platinum(IV) chloride. The distribution coefficient for platinum(IV) chloride goes up through a maximum at just over 6M HCI and 50% TBP in toluene, but decreases at low and high HCI concentration. IL was found that the extracting species has the formula 3TBP·H₂PtCl_6·χH₂O. Unextracted platinum(IV) in the aqueous phase is determined directly and platinum(IV) in the organic phase is stripped with H₂O and determined by stannous chloride method, respectively. In a binary mixture of gold and platinum, the solvent exhibited toward gold that it could be extracted selectively from platinum. |
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