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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.
In the GAMI pre-baked process; alumina is converted into primary aluminum through a smelting process using electrolytic reduction. The reduction process takes place in a reduction cell, referred to as the pot, where alumina is reduced to molten aluminium. From the pot-line, the molten aluminium is sent to the fabrication facility. |