DRDO has developed a state-of-the art technology for
the production of titanium sponge, which is the principal raw material for
the manufacture of Ti alloys for aerospace and various corrosion resistance
applications. Titanium sponge is mainly produced by high temperature
magnesio-thermic reduction of titanium tetrachloride, which is prepared by
carbo-chlorination of mineral concentrates. Currently, the sponge production
is being practiced commercially by only a select group of four or five
countries in the world.
The indigenous technology development program involved design and
development of various systems and equipment, study and fine tuning of
important process parameters, and technology demonstration with adequate
consistency and reproducibility of sponge quality involving the following
activities of sponge production:
Purification of raw titanium tetrachloride (TiCl4) in two packed beds
distillation columns for removing dissolved gases, low and high boiling
impurities, chlorides to prepare ‘metal grade’ tetrachloride continuously
at the rate of 150 kg/h.
Reduction of pure TiCl4 by magnesium metal followed by vacuum separation
of titanium sponge to remove entrapped Mg/MgCl2 employing a twin reactor
assembly made of stainless steel, and an electrical resistance furnace to
produce the metal in a batch size of about 3000 kg of sponge.
Process automation and data logging using a Distributed Control System.
Ejection of titanium sponge cake from the reactor followed by a series of
mechanical processing operations for careful gradation and size reduction
to prepare homogenous sponge lots suitable for ingot melting.
The technology gap hitherto prevailing in the titanium metal production
has been bridged. It would pave the way for setting up of the first
commercial plant for titanium sponge production in the country to
gainfully exploit the vast titanium mineral reserves.