Analysis of High-Purity Chromium

A combination chemical-spectrographic method for determining metallic impurities in high-purity chromium is described. Chromium is removed from the metallic impurities by volatilization as chromyl chloride. The remaining solution is examined spectrographically for elements such as iron, nickel, aluminum, manganese, titanium, vanadium, magnesium, and copper in the 0.1- to 30-ppm range. Direct arcing of chromic sulfate is used for the determination of silicon.