Here is your essay on Chromium

It is an important alloying element in the manufacture of steel Chromite is the only ore-mineral of chromium.

Chromite-FeO, Cr203, Cr203=68.0% and Cr=46.66%.

Origin:

Chromite deposits are magmatic segregations in ultrabasic igneous rocks of Archaean age. Chromite is associated only with highly basic or ultrabasic rocks like peridotite, saxonite dunite and pyroxenites or their alteration product, serpentine rock.’

Mode of Occurrence:

Chromite deposits occur as lenses masses, veins and disseminated grains in host rocks. The deposits are regarded as the early or late magmatic segregation or injection product.

Distribution in India:

The largest chromite deposit in the country is located in the Sukinda-ultrabasic belt of Cuttack and Dhenkanal districts of Odisha, and also in the Keonjhar district of the state. The belt extends over a distance of about 20 km. the width of the belt is about 2 km. The ore bodies are lenticular in shape, and occur as lenses and patches within the lateritised ultra- basic rocks. The following types of ores are found to occur viz.

(i) massive ore

(ii) banded ore

(iii) disseminated ore

(iv) ferruginous lateritic ore

(v) powdery or friable ore

(vii) conglomeratic ore

(vii) placer ore etc.

The reserve is estimated to be about 8 million tonnes.

The other important deposits occur in:

(i) Andhra Pradesh:

Kistna district (Kondapalle).

(ii) Bihar :

Singhbhum district.

(iii) Karnataka:

Chitaldrug, Hassan and Shimoga districts.

(iv) Tamil Nadu:

Salem districts (Sittampundi).

Economic uses:

(i) In the metallurgical industries in the production of various non-ferrous alloys of chromium and also in the form of ferro-chrome for manufacturing chrome steel.

(ii) In refractory industries, due to its high resistance against corrosion, high temperature and sudden temperature changes and its chemically neutral character.

(iii) In chemical industries, for the manufacture of chromium compounds like chromates and bi-chromates and chromic acid etc.