Although there are more than ten known chromium minerals, only one is a source of commercial importance. This mineral is known as chromite and has the theoretical composition FeCr2O4 containing 68 % of chromic oxide ( Cr2O3 ), in which the proportions of Mg2+, Fe2+ and Cr3+, Al3+, Fe3+ may vary considerably.
The main product generated by chromite is ferrochrome, a major player in the steel industry. In particular the stainless steel industry uses more than 90 % of the world’s chromite output. The mining and steel industries must assess the quality of the chromite ore to optimize the grade of their stainless steel production. As a result, the chemical analyses of the chromite ore as well as its final and waste products are mandatory. Metal analysis traditionally uses AA or ICP-OES to measure the metal contents in the ores and industrial products. However, the traditional dissolution method for chromite and ferrochrome is a multi-step, multi-acid digestion which requires the use of HNO3, HF and HClO4 and can take between 1 to 3 hours.