In 2009, only 2% of the world's production of chromite was used for chromium chemicals. Nevertheless, these play an important part in the world's chemical industry. Sodium chromate is the primary product in the manufacture of chromium chemicals.
Approximately 638,000 tonnes of sodium dichromate were produced in 2009. It is produced by reaction in a rotary kiln to which the chromite is fed together with soda ash (sodium carbonate) and sometimes ground lime, limestone or dolomite.
The sodium chromate is then converted into a variety of chemicals including sodium dichromate, ammonium and potassium dichromate, chromic acid, chromic oxide and basic chromium sulphate.
The earliest use of chromium chemicals was during or before the 19th century for colour and pigment applications, due to their very bright colours.
Currently, the largest use of chromium chemicals is as basic chromium sulphate in the leather tanning industry.
The second largest use of chromium chemicals is in the metal finishing industry. Main applications include decorative chromium plating, hard chromium plating for engineering requirements, and pickling of plastics.
Pigment applications are still important for chromium chemicals, sometimes mixed with other elements. The pigments are all very brightly coloured in clear yellow, orange, green, turquoise and blue. They are used in paints, plastics, ceramics and surface finishes.
Pure chromium oxide is used alone or together with alumina, zirconia and silica for high temperature and attack resistant refractories.
Other, smaller, applications include the use of chromium chemicals catalysts and oxidants in commercial chemical synthesis.