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Aluminium Ore of India
Aluminium is the 3rd most abundant element of the earth’s crust after
O and Si. It is not found in a free state rather present as a compound with
another element.The importance of aluminium metal is high enough just like
that of iron. India has the credit to be the fifth largest producerof aluminium
in the world. India can have the capacity to produce more than 2.7 million
tons of aluminium per annum which is 5% of the total aluminium production
on the globe. The chief ore of aluminium is Bauxite and in 2019, more than
26 million millions metric tons of bauxite were produced in India.
Mineralogy:
As previously said the chief industrial ore of aluminium is bauxite
(Al2O3, H2O). Bauxite is not a single mineral but it is the aggregate of
several hydrated aluminium oxides like Gibbsite,Boehmite,and Diaspore.
They have variations in alumina content, iron oxides, halloysite, kaolinite,
and nontronite.
Commercialbauxite occurs in three forms:
1. Pisolites or oolites
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2. Porous spongeore,
3. Amorphous or clay ore.
The bauxite containing more than 58% Al2O3 and less than 5% iron is
used for the metallurgical purpose.The boundary between ferruginous
laterite and bauxite is, however, gradational, laterite with >50% Al2O3 is
called bauxite.
Mode of Occurrence and Origin:
Bauxite depositoccurs,
1. Blanketat or near the surface
2. Interstratified beddeddeposits lying on erosionalunconformity.
3. Pocketdepositsor irregularmasses in limestoneor dolomite
4. Transporteddeposits.
Blanket deposits:
They generally have some soil cover and are represented bythe caps of
the high plateaus, e.g. in western Chota Nagpur and Raj mahal hills (Bihar)
Amarkantak (MP), Kolhapur, Sarata, and Ratnagiri (Maharashtra). This
may be the residual of continuous sheets of Decan trap which has been
subjected to subaerial weathering. The alternate dry and wet seasonlead
to the enrichment of iron and aluminium oxides and leached other
chemically susceptible elements.The blanket deposits are in-situ and the
original textural features of the parent rock.
Interstratified deposits:
The bauxite depositof Saurashtra and Kuchch of Gujrat. It is deposited
between the Decan trap and tertiary sediments and represents the
interstratified type.
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Pocket deposits:
Several isolated pocketdeposits of bauxite with yellow fossiliferous
limestone are noticed along the coast betweenLamba and Miani,
Saurashtra region. The bauxite depositsin the Ahmedabad region occur as
elongated and funnel-shaped pockets resting over surfaces of limestone.
Transported deposits:
Bauxite may also be deposited inthe sedimentary sequence by reworking.
1. Those close to the source area, resulting in the pseudo-brecciated
bauxites
2. That far from the source area as indicated by bauxite conglomerates
and grits with well-rounded pebbles and grains of bauxites.
Distributions:
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Kannad
Tamil Nadu Salen, Nilgiri and Madurai
Kerala Cannore, Quilon
Uttar Pradesh Banda, Latipur, Varanasi
Rajasthan Kota
Uses of Aluminium:
Aluminium is useful for its lightness, brightness,soft
and ductile nature. It is widely used in making utensils, aeroplanes and
rockets. This metal is a good conductorfor heat and electricity, so it is also
used in the electricalindustry. Its compounds are also used in various
chemical industries for making paints, preservation aluminium foils,filter
paper, and medicinal compounds.
Fire clay
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Fire clay is a clay that can sustain high temperature without melting.
This clay is deficient in iron oxide, lime, magnesia, and alkali but rich in
alumina and silica. The heat resistance of fire clay increases with the
increase in the proportion of alumina.
Mode of occurrence and origin:
The fire clay mainly occurs under the coal seams as thin lenses or
bedded form, it may exhibit minor lamination. The low gradient stream
carried suspended matters which deposits into the coal swamps. In the
process of deposition, the coarser particles are subjected to deposit in the
margin of the bank while the finner sediments depositinto the basin centre.
The pressure and temperature which helps to form coals also initiate the
formation process of fireclay.
Distributions:
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State District
Andhra Pradesh East and WestGodavari, Adilabad
Bihar Bhagalpur, Dhanbad, Giridih, Hazaribagh,
Deogarh, Palamau, Ranchi, Santhal Pargana
Gujrat Kuchch, Rajkot, Sabarkantha, Surendranagar
Karnataka Chitradurga, Hassan
Madhya Pradesh Jabalpur, Satna, Sidhi
Maharashtra Amravati, Kolhapur, Sindhudurg
Odisha Cuttack, Dhenkanai, Puri, Sambalpur, Sundargarh
Rajasthan Alwar, Bikanir, Jhunjhunu, Sawai
WestBengal Birbhum, Burdwan and Purulia
Fireclays deposits several places in India but the best quality fire clay
is recovered from lower Gondwana rocks of West Bengal i.e. Birbhum and
Burdwan, and in Dhanbad, Hazaribag of Jharkhand state.
Uses of Fire clay:
Fireclay is chiefly consumed in the refractory industry. Several kinds
of fireclaybricks are manufactured by admixing of calcined bauxite or kyanite
in suitable proportionto make insulators. These bricks are utilized in most of
the industries in iron, steel, ferroalloys, cement, and glass. The other uses
are in the ceramic, abrasive, chemical, paper, rubber, and textile industry.
References:
