Patent ID: 7563420

Claim:
A method of refining an Rh-containing hydrochloric acid solution also containing Ag and at least one other impurity of heavy metals and alkaline earth metals, the method comprising the steps of: (a) adding an alkali to the solution to adjust pH of the solution to 7-12, whereby generating a neutralized precipitate containing Rh and other components; (b) filtrating and separating the neutralized precipitate; (c) adding a first hydrochloric acid for dissolving the neutralized precipitate in an amount such that the mole ratio of Cl to Rh of a resulting solution becomes 3-4; (d) filtering the resulting solution to remove Ag as precipitate, and (e) extracting the solution obtained by the previous step as an aqueous phase with di(2-ethylhexyl)phosphoric acid.