24-11-2012, 02:43 PM
BHARAT ALUMINIUM COMPANY (BALCO)
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BALCO, the 1st PSU was established in the year 1965 But it started production in 1975.
Starting production of 1,00,000 tonnes aluminium per year.
Expanded its smelting capacity to 3.34 lakhs tonnes along with corresponding increase in alumina production and power generation capacity.
INTRODUCTION
BALCO’s Korba plant is an integrated aluminium complex, having facilities from bauxite mining to down stream products. It is located in Korba district of Chhattisgarh. The BALCO plant is nearly 10 km away from the Korba city. The principal raw material, Bauxite, is supplied from mines located at Mainpat near by Sarguja district. Water has been made available from neighbouring Hasdeo barrage canal. The Korba plant is having one 540 MW and 270 MW captive thermal power plant.
UNITS OF BALCO
There are 5 units of BALCO company ,these are
1)BALCO Plant 1
2)BALCO Plant 2
3) BALCO Mainpat mines
4) BALCO Captive power plant 1(bcpp 1)
5) BALCO Captive power plant 2(bcpp 2)
The integrated aluminium plant of Balco consists of three sections: -
Alumina plant
Smelter plant
Fabrication plant.
Extraction of Alumina (pure aluminium oxide- Al2O3) from Bauxite by chemical process is done in Alumina plant, whereas the Electrolysis of Aluminium is carried out in Smelter plant to obtain molten aluminium metal. In the third stage, the molten aluminium is cast and shaped into various forms as end product
SMELTING PROCESS
The Smelter is based on Hall & Heroult Process (Vertical Stud Soderberg Technology). The Smelter is made up of electrolytic cells, in which the process of electrolytic reduction is carried out to convert calcined alumina to aluminium.
Calcined alumina is transported by tankers from the alumina plant and is stored in silos. There are 408 cells connected in two series of 204 cells each to which the alumina is fed from the storage silos at fixed intervals. Cryolite is mixed with the alumina and this solution is maintained at a temperature of 960 to 9750 C to carry out the process of electrolytic reduction. The technology employed is the self baking vertical stud Soderberg anode with a cell rating of 100 KA current intensity. The anode paste and alumina are thus charged at regular intervals
From the electrolyte, foam carbon is removed by froth flotation and the recovered cryolite is recycled back to the cell house.
Exhaust Gases are treated with soda solution in gas cleaning plants having scrubbers, to recover fluorine. The enriched solution is sent to the Cryolite Recovery Plant where it is treated with sodium aluminate liquor to get back cryolite, which is recycled and sent to the Cell House
FABRICATION PLANT
The word Fabrication literally means to manufacture or to produce. In Fabrication plant mainly the facilities like casting and shaping of Aluminium metal, which is produced in the Smelter Plant, is done. This is done in order to make saleable products like: - rods, rolled products, slabs etc. The Fabrication plant namely consist of: -
Cast House
Foundry Shop
Sheet Rolling Shop (SRS).
CAST HOUSE
The principal objective of cast house is the production of Aluminium rods from the molten metal. The metal used in the cast house is the product of Oil Fire Hearth Furnace. The molten metal that is obtained from the Smelter plant is at the temperature of 960-970oC, but due to transportation the temperature of metal reduces to 850oC.This metal is fed into the furnace where the temperature is maintained at 750o C. The main purpose of this furnace is to remove the impurity from the molten metal.