Chromite is the principal source of chromium. Chromite occurs as a product of magmatic differentiation in the form of segregation masses and veins in ultrabasic, intrusive rocks like dunities, peridotites, serpentines etc. Chromite is useful as a refractory in metallurgy; it can withstand high temperature and therefore the bricks made with ferrochrome are used in lining furnaces.
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It is used in making chemicals, as chromates and dichromates, used in tanning of leather, paint making calico-printing and photography. It is used in refractory industries due to its high resistance against corrosion, high temperature changes and its chemically of neutral character.
Production and Distribution:
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Total in situ reserves of chromite are estimated at 114 million tonnes as on 1 April 2000. Total geological resources were estimated at 187 million tonnes, consisting of around 114 million tonnes in situ reserves and about 73 million tonnes as conditional resources. The largest share (about 96 per cent) in the total geological resources is accounted by Cuttack district in Odisha.
Deposits of economic significance occur in Odisha, Karnataka, Maharashtra, Jharkhand, Madhya Pradesh, Chhattisgarh, Tamil Nadu and Manipur. However, refractory grade reserves of chromite are very meagre. The production of chromites at 4.26 million tones in 2010-11 by 24.42% as compared to previous years. Odisha reported almost entire output of chromites 99% in the country. The chromite deposits are confined to Pre-Archean and Mesozoic Tertiary periods.
Odisha:
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Orissa accounts for more than 90% of the country’s deposits of chromites located in the valley of Jajpur district and Baula Nuasahi belt of Bhadrak district. Sukinda valley is flanked by the Mahagiri range and Daitari range. High grade deposits are situated in the Keonjhar, Cuttack and Dhenkanal districts. The Cuttack-Dhenkanal chromite belt runs for 48 kms in Cuttack districts by way of Dhenkanal.
Jharkhand:
Important chromite deposits occur in Singhbhum district. There are sporadic occurrence in Ranchi district, Rorburu, Kiriburu, Kittaburu and Chittang Buru regions around Jojohatu area.
Tamil Nadu:
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A few sporadic and commercially unimportant pockets, occur in ‘Chalk Hills’ near Salem. It occurs in the Coimbatore district also. A large deposits of low grade chromite occurs in Salem districts as layers in a belt of corundum-bearing anorthosite rocks south of Sitampundi extending over a large area.
Uttar Pradesh:
The recoverable reserves from the state, of all grades of bauxite have been reported from the districts of Banda, Lalitpur and Varanasi.
Karnataka:
Chromite occurs in veins, lenses and as segregations between Mysore and Nanjanagud. In Hassan district, there are a number of occurrences. The ore is massive, friable and contains 48 to 50 per cent chromic oxide. The main chromite belt is the Nuggchalli belt which extends upto 125 kms and carries the important deposits of Byrapur, Chikonhalli, Pensamdura, Bhaktarahalli, and Jampur with a width of nine metres.
Ladakh:
Chromite is found amidst dunites intruding the upper cretaceous volcanic rocks of Dras. The dunites which have been partly altered into serpentine rocks are seen in abundance on a hillock known as Brown Hill in the vicinity of Dras. The chromite here occurs sporadically as veins and irregular magmatic segregations.
Maharashtra:
The known chromite deposits occur in Ratnagiri district and near Pauni in Bhandara districts. In both the areas the chromite is of low grade. The mineral content is 31 to 38 per cent.
Himalayan Arakan Belt:
Chromite of the younger deposits of the Himalayan Arakan belt is associated with the ultrabasic including the limestone. It includes Eastern Himalayas, Arakan Yoma and Andamans.
Manipur:
Recoverable reserves of refractory grades of chromite has been assessed in Tegnupal and Ukhrul districts of Manipur.