Determination of Chromium in Nickel-bearing Matrix Material Obtained by Pyrometallugy-Oxidation with Ammonium Persulfate and Titration with Ferrous Ammonium Sulfate

The method of oxidation with (NH4)2S2O8 and titration with (NH4)2Fe(SO4)2 solution as titrant was applied to the determination of chromium in nickel-bearing matrix material obtained by pyrometallurgy. It was shown that complete dissolution of the sample, including its componental chromium, was accomplished by treating with HCl, HNO3 and few drops of HF, and followed by fuming with mixed acid of H2SO4-H3PO4. The proposed method was used in the analysis of 3 standard samples, giving results of Cr-contents in consistency with the certified values. 6 samples of the Ni-bearing matrix material were taken and 11 determinations of their Cr-contents were carried out by this method, values of RSD′s found were in the range from 0.76% to 2.0%.