Spectrophotometric determination of phosphours in ferrochromium

Abstract

It is known that ferrochromium of lower carbon is usually decomposed with perchloric acid, and that the one of middle and higher carbon is acidified with nitric acid after it is decomposed habitually with sodium peroxide. The acidity is then adjusted to reduce chromium by adding sodium hydrogen sulfite and to it was added ammonium molybdate immediately. The solution was extracted with a solvent mixture (n-butanol + chloroform) to separate phosphomolybdic acid and to the extract stannous chloride was added for the reduction. The absorbance of the molybdenum blue produced were measured at a wavelength of around 700 mμ to determine the phosphorous content. The operation period of time was found to take 60 to 80 min.