Wednesday, November 4, 2009

MANGANESE ORE

MANGANESE ORE In terms of composition of the manganiferrous ores with regard to the proportion of manganese to iron, it is customary to use the term manganese are for those containing over 40 per cent of manganese. The most common minerals are braunite, pyrolusite, psilomelane and manganite. The are contains impurities like silica, lime, alumina, magnesia and phospho­rus.

Manganese is used as a ferro alloy; it removes gases. and acts as a cleanser in the manufacture of steel. Man­ganese is also used as a decoloriser in glass, and in the manufacture of bleaching powder and electric batteries.

Classification The manganese ores, on the basis of their manganese content, may be classified into the follow­ing grades:

(a) Chemical grade
(b) Metallurgical grade
First grade More than 48% of manganese
Second grade 45-48% of manganese
Third grade 45% of manganese
(c) Manganese are 35-45% of manganese
(d) Ferrugenous manganese are 10-35% of manganese (e) Manganiferous iron are grade 10% of. manganese

For trade purposes, Indian manganese ores are clas­sified as follows:
(a) Battery grade 80-86% of Mn02
(b) Peroxide grade 78% MnO + 4% Fe
(c) High grade 46-48% of Mn
(d) Low grade 38-40% of Mn
(e) Ferrugenous grade 30-35% of Mn

Distribution in the World
Former USSR, South Africa, Gabon, Australia, Brazil, France and India are major pro­ducing centres.

Distribution in India
India is the third largest producer of manganese ore in the world. The country's most important ore deposits occur in the form of sedimentary stratified metamorphic deposits in the Dharwar system. The manganese deposits are generally either syngenetic (sedi­mentary) as in Madhya Pradesh and Maharashtra, epige­
82-87% of manganesenetic (residual enrichment and oxidation) as in Jharkhand, Orissa, Goa and Kamataka, or lateritic and supergene enrichments associated with the first two groups. On the basis of mode of occurrence and association with different kinds of country rocks, the Indian manganese ore deposits have been classified as

(a) gonditic ores which are associated with metamorphosed manganiferous sediments;

(bJKoduritic ores which are produced due to reactions between the country rocks and an invading magma or granitic compo­sition;

(c) lateritoid ores which are produced due to meta­somatic replacement and residual concentration. Georgia has huge deposits of manganese ore.
India is the third largest producer of manganese ore in the. world. The country's most important are deposits occu( in the form of sedimentary stratified metamorphic deposits in the Dharwar system.

In India, extensive and rich manganese deposits occur in Madhya Pradesh, Orissa, Jharkhand, Andhra Pradesh, Maharashtra and Karnataka. Indian manganese deposits display some distinct geological formations, which arc;

(a) deposits associated with the khondalite rocks (gar­net, sillimanite, gneisses) found in the Srikakulam district of Andhra Pradesh and in the Kalahandi and Koraput districts in Orissa;

(b) deposits associated with the iron ore bearing rocks (schists) found in Karnataka state in the Sandur hills, as the Bisgold-Yellapur deposits in North Kanara, and in the Chitradurg and Shimoga belt, and the Supa-Dandcli areil of North Kanara;

(c) deposits associated with limestone ilnd dolomite which occur in the Sausar-Manganese-Marble .province of Madhya Pradesh, Jharkhand and Gangpur (Orissa), Ratnagiri in Maharashtra, and Panch Mahal and Vadodara districts of Gujarat. The deposits of the group are generally ~mall and often have high phosphorus as in the case of ores from Srikakulam districts. Manganiferous shales and banded manganiferous rocks with friable layers of quartz are found associated with iron are group of rocks in Karnataka and Goa-Ratnagiri. In Jharkhand and Orissa the ore is low in phsophorous and h!gh in iron.

No comments:

Post a Comment