Methods for the separation of platinum, palladium, rhodium, and iridium from one another and for their gravimetric determination

Abstract

A method is described for the analytical separation of platinum from each or all of the three metals, palladium, rhodium, and iridium. It is based upon the complete precipitation of the hydrated dioxides of palladium, rhodium, and iridium in a boiling solution containing sodium bromate and having an acidity of pH 6. Two precipitations of the hydrated dioxides were found to be sufficient to effect the quantitative isolation of platinum. The separation of palladium from rhodium and iridium, by means of dimethyl-glyoxime, and its subsequent determination are also described. The procedure for the separation of rhodium from iridium by titanous chloride and for the deter-mination of these two metals, given in detail in a previous publication from this laboratory, is discussed only briefly in this paper.