SEPARATION OF PLATINUM BY THE EXTRACTION SYSTEM OF AMMONIUM THIOCYANATE AND ETHANOL IN PRESENCE OF AMMONIUM SULFATE

It was found that platinum(Ⅳ) was quantitatively extracted into ethanol in the form of Pt(SCN)2-6 in the presence of relatively large amount of ammonium sulfate from a solution of pH 3.0.The optimum amounts of the reagent present in the extraction system were as follows: NH4SCN 20 g·L-1,(NH4)2SO4 300 g·L-1 ethanol 0.30 mL·mL-1.Under these conditions,Pt(Ⅳ) was effectively separated from appropriate amounts of Ni(Ⅱ),Cr(Ⅲ),Co(Ⅱ),Fe(Ⅱ),Mn(Ⅱ),Al(Ⅲ) and Rh(Ⅲ).This method has been applied to the analysis of Ni-Pt/Al2O3 catalyst as a separation process,and 5 determinations of Pt(Ⅳ) in a catalyst sample were performed giving an average result of w(Pt) 0.104% with RSD of 1.7%.