Precision spectrophotometric determination of chromium in chromite ores and ferro-chrome

Abstract

The chemical and manipulative variables have been examined in detail in order to develop a precise and direct spectrophotometric determination of chromium in chromite ores and in ferro-chrome. Samples are sintered with sodium peroxide in zirconium crucibles for 3 h at 510 ± 10 °C, then leached, filtered, acidified with perchloric acid and reduced with hydrazine hydrate. Chromium is determined from the absorbance of the chromium(III) aquo ion at 410 and 578 nm. The procedure has been evaluated using standard chrome ores, ferro-chrome alloys and a series of Sudanese and industrial ferrochrome samples. The results are in good agreement with, and of comparable precision to, published data and to those obtained by titrimetric assay.