Bharat Aluminium Co. Ltd. (BALCO) was incorporated
in the year 1965 as a Public Sector Undertaking (PSU).
BALCO has several “firsts” to its credit. It is the first public
sector enterprise in the country which started producing
aluminium in 1974. In 1987-88, a captive power plant of 270
MW was added to cater to the power requirement of the unit.
BALCO has been the first in the Indian Aluminium Industry to
produce the Alloy Rods, which is a Feedstock for all
Aluminium Alloy Conductors, very much needed for today's
power transmission lines. Till 2001, BALCO was a public
sector enterprise owned 100% by Government of India
(GoI). In the year 2001, GoI divested 51% equity and
management control in favour of Sterlite Industries (I)
Limited.
Bharat Aluminium Company Limited (BALCO) is
situated at Korba in Chattisgarh. It is an integrated plant
with production capacity of 200,000 MT/yr of Alumina and
1,00,000 MT/yr of Aluminium metal with down stream
facilities to produce various cast, rolled and extruded
products. The alumina plant was designed with know-how
supplied by Aluterv-FKI (Chemokomplex) of Hungary and
commissioned in April 1973.
BALCO Alumina refinery is situated at korba district of
Chattisgarh state ( Previously Madhya pradesh).The plant is
located at around 240 kilometer from Raipur , 45 kilometer
from Champa and 9 kilometer from korba.
The development of special aluminium alloys for
‘Intermediate Range Ballistic Missile’ Agni and ‘Surface
Missile’ Prithvi have been significant achievements of
BALCO contributing to the nation's defence capabilities.
200,000 tonnes of alumina production capacity, 100,000
tonnes per annum of smelting capacity, three Properzi Rod
Mills, three pig casting machines, integrated hot and cold
rolling mills, a captive power plant of 270 MW capacity are
just a glimpse of BALCO's production capacity built over the
last 39 years of its existence.
The year 2003-2004 has been a high performance year
for BALCO. BALCO achieved the:
Highest ever calcined alumina production
Highest hot metal production
Highest saleable metal production
Mining Process :
Bharat Aluminium Co. Ltd. (BALCO) has Captive
Bauxite mines. The method of mining is open cast semi-
mechanized. Overburden, which is in the form of soil &
laterite, is first excavated by a combination of shovel /
excavator and dumper in order to expose ore-zone. Then
the ore zone is drilled and blasted. The blasted ore is subject
to sorting in order to upgrade the “Run of Grade” to “Plant
Feed Grade” i.e. 48% Al O . Sorting is carried out at the
23
mine-face and the rejects associated in the ore zone are
back-filled concurrently. The area is then leveled and
afforested. The sorted ore is then trucked to the Korba
complex for further processing.
Mines :
Mainpat is the primary operative mine, which produces
approximately 500,000 tpa of Bauxite. Approximately
100,000- 150,000 tpa Bauxite is procured on commission
basis from non-captive mines. There are plans to open
another deposit named BodaiDaldali in Kawardha District in
the near future.
Manipat has about 5.0 million tonnes of reserves while
Bodai-Daladai has 7.11 million tonnes of Bauxite reserves.
Alumina Refinery :
Process Technology : Bauxite is the main raw material
used for the production of alumina. The mineralogical form
in which the alumina is bound distinguishes the different
types of bauxite. They are then called gibbsitic, boehmitic or
diasporic bauxite. The Alumina (Aluminium oxide) is
extracted from bauxite using Bayer Process.
Element Quantity Mineralogical Composition
Aluminium Al O :2 3
35 to 65%
Gibbsite Al(OH)3
Boehmite AlOOH
Diaspore AlOOH
Substituted Goethite
Silicon SiO :2
35 to 65%
Quartz
Kaolinite
Opal etc…
Iron Fe O :2 3
2 to 30%
Goethite
Hematite
Siderite
Titanium TiO :2
0.5 to 8%
Anastasite
Rutile
Calcium CaO:
0 to 55%
Calcite
Dolomie
Magnesite
Alumina Refining :
The aluminum industry relies on the Bayer process to
produce alumina from bauxite. It remains the most
economic means of extracting alumina, which in turn is vital
for the production of aluminum metal - two to three tonnes of
alumina are required to produce one tonne of aluminum,
depending upon the content of alumina in the bauxite.
Bauxite is crushed, ground and digested in caustic soda
(sodium hydroxide) at high pressure and temperature. The
resulting liquor contains a solution of sodium aluminate and
undissolved bauxite residues containing iron, silicon, and
titanium. These residues, known as “red mud”, settle
gradually to the bottom of the settling tank and are filtered
and removed.
The clear sodium aluminate solution, which is called
aluminate liquor, is pumped into a huge tank called a
precipitator. Fine particles of alumina are added to seed the
precipitation of pure alumina particles as the liquor cools.
The precipitation process is a batch as well as continuous.
The solid particles concentration increases, which are
removed, filtered and washed, and are then passed through
a rotary or fluidized calciner at 1100°C to drive off the
chemically combined water. The result is a white powder,
pure alumina. The caustic soda, which is called, spent
liquor is recycled and returned to the start of the process and
used again.
The Bayer Process :
Today all the alumina produced from bauxite uses the
Bayer Process -an economical method of producing
aluminium oxide which was discovered by an Austrian
chemist Karl Bayer and patented in 1887.
The process dissolves the aluminium component of
bauxite ore in sodium hydroxide (caustic soda), removes
impurities from the solution; and precipitates alumina
trihydrate, which is then calcined to aluminium oxide
Bauxite usually consist of 2 forms of alumina a
monhydrate form Boehmite (Al O .H O) and a trihydrate
23 2
form Gibbsite (Al O .3H O).
23 2
o
Boehmite requires elevated temperature (above 200 C)
to dissolve readily in 10% sodium hydroxide solution. The
trihydrate grade bauxite (mainly Gibbsite) dissolves readily
in 10% sodium hydroxide solution at temperatures below
o
150 C.
Consequently, monohydrate bauxite undergoes high
temperature extraction under pressure in digesters.
Technology adopted :
High-pressure digestion technology is adopted for the
production of Alumina.
The Plant consists of the following main establishments:-
Crushing and Grinding Section ; Slurry storage &
Desilication ; Slurry Preheating & Digestion Section ;
Dilution, Settling & Washing Section ; Red Mud Filtration &
Causticization Section ; Aluminate Liquor Cooling & Spent
Liquor Thickening Section. Precipitation & Hydrate Filtration
Section ; Evaporation & Salt Removal Section ; Calcination,
Raw Material & Lime Slaking Unit.
The Bauxite received from mines is stored in the open
bauxite yard. It is blended and crushed. The crushed
bauxite is then conveyed to Ball Mill section where the
bauxite along with the recycled caustic soda solution called
digestion liquor is ground. The slurry after grinding is stored
in tanks and pumped to Desilication units after preheating.
The desilicated slurry is digested in the series of digesters
by steam at high pressure. The digested slurry is flashed
and diluted before going to settling tanks. Flocculants are
added for faster sedimentation of the mud. The settled mud
(called Red Mud) is subsequently washed before going to
red mud disposal area.
Hydrocyclone :
Under modernization programme with installation of
Hydro cyclone which has pivot role for hydrate filtration.
Raw and fine crystals of alumina hydrate are separated
through hydrostatic process from hydrate liquor. Fine
crystals are resent to precipitation for seeding whereas raw
crystals are sent as product to calcinations through filtration
process where finally it is turned into alumina powder. By
way of using the hydro cyclone in alumina plant, the
production and productivity is supposed to be improved 3040%.
It has been fully designed and prepared by Balco
engineers only at about 20% of its cost for the same product
available in the market.
The clear supernatant liquor (called aluminate liquor) is
filtered and cooled in heat exchangers. The cooled
aluminate liquor is then pumped to precipitation unit. The
precipitated hydrate is filtered, washed and stored in
hydrate godown.
The product hydrate is fed to kiln where it is calcined at a
temperature of 1200°C.
The Calcined alumina is stored in silos.
Smelting Process :
Bharat Aluminium Co. Ltd. (BALCO) uses VSS
(Vertical Stud Soderberg) technology to produce Aluminium
from Alumina. Alumina is dissolved in an electrolytic bath of
molten cryolite (Sodium Aluminium Fluoride) within a large
carbon or graphite lined steel container known as a "pot".
An electric current is passed through the electrolyte at
low voltage, but very high current. The electric current flows
between a carbon anode (positive), made of petroleum coke
and pitch, and a cathode (negative), formed by the thick
carbon or graphite lining of the pot. Molten Aluminium is
deposited at the bottom of the pot and is siphoned off
periodically. It is then taken to a holding furnace, cleaned
and then cast.
Balco Fabrication :
For the past 30 years Bharat Aluminium Company has
been dedicated in developing World Class Quality
aluminium plates and sheets of various alloys. To stay
ahead of competition it has adopted many state of the art
technologies and has firmly established itself as a frontrunner
among the producers of aluminium sheets and
plates.
Since 1980 Balco is catering to the needs of Defence
and Space Research. The following sophisticated alloys
have been developed and supplied for defence and space
applications:
1 AFNOR 7020 Rocket fuel storage tank for ISRO
2 AA 2219 Cryogenic applications for VSSC, Trivandram.
3 DTD 5124 Ammunition hardware for O.F., Ambajhari.
4 DTD 5024 Weldable secondary structural Components
for O.F., Ambajhari
90% of the aluminium alloys used in the 'Agni', 'Prithvi'
and 'Akaash' missiles, which have been test fired
successfully, were supplied by Balco.
Cast House :
1) Properzi continuous rod casters
2) Twin Roll Continuous Caster along with SNIF degasser
(Maximum coil weight 10 tons, width 1750mm maximum)
3) Hydraulically driven semi continuous ingot Casting
machine.
Sheet Rolling Shop :
1) This is the only 4 high Hot Rolling Mill in India.The HRMof
Balco is having the capacity to roll the widest slab (up to
1560 mm) plates among all the HRM installed in India.
2) The HRM contains a vertical rolling stand for edge rolling
of the plates, which minimize edge cracking.
Balco is having a 4-High reversible rolling mill which
neither Hindalco nor Indal is having. The 4 - High mill helps
to minimize shape variation in sheets.
The salient features of the new Cold Rolling Mill
installed are given below:
1) Hydraulic automatic gauge control.
2) Shapes and flatness control.
3) Quick roll changing system.
4) Computerised controls with process sequence controls.
Corporate social responsibility initiatives
by Balco :
As a responsible corporate Balco has structured
programmes and projects as a part of Community
Development Initiatives. The operational area falls within 5
kms radius namely Dhondro, Rogbhary, Bhadrapara and
Lal Ghat. The thrust areas under which initiatives have been
undertaken are: Health, Education, Sustainable Livelihoods
and Social Mobilisation. In the area of health Balco mobile
medical team visits the four villages every week and renders
health check up facilities to villagers at their doorsteps and
medicines are distributed free of cost. The villages have
Swasth Mitras trained by Balco render first aid to the needy.
The health projects undertaken are: to develop awareness,
prevention and treatment of Tuberculosis, Malaria, Water
borne diseases and HIV AIDS awareness. Family Planning
and Malnutrition in children also forms a major project. In
addition to this Balco has also upgraded the PHC at Korba
by providing a new X ray Room and renovated the General
Ward.
In the area of village development and sustainable
livelihood we have programmes like Project Kadambari to
promote vegetable cultivation and floriculture in the villages.
Plantation of bio diesel generating Jatropa Plantation micro
credit management, revival of SHGs are some of the
projects under implementation. Mindsets of farmers are
being changed to cultivate cash crops and fruit bearing
plants. Rainwater harvesting and drinking water projects
are being given priority and are in the pipeline. In the area of
education, Non Formal Education classes are held in two of
the operational areas thrice a week. Also training of women
is being undertaken in collaboration with the Government
Polytechnic to empower women to earn their livelihoods.
Members of SHG have started production of Dona for which
marketing tie ups are in place.
Through above Projects and Programmes which are
participatory in nature Balco involves the local panchayats,
government agencies and NGOs to raise the living
standards of the people in a holistic and sustainable way.
The company takes every proactive and conceivable
steps towards prevention of pollution and conservation of
natural resources like water, energy and for reducing,
recycling and reusing of waste.
BALCO has been accredited with ISO: 14001 and
OHSAS: 18001 Certification. This has resulted in enhancing
the awareness in the field of environment as well as
occupational health and safety practices at work
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