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Zircon
has a good resistance to alkalies in flue gases and corrosion from molten
glass. It has established uses in glass furnaces, repairs to crowns and
superstructures, bottom sealing and patching, filling expansion joints and
for the settling of refractory bricks and blocks. Zircon also resists
many aggressive chemical compounds and therefore is beneficial for coating
burner quarls and other target refractories where deposits, particularly
from oil firing can be destructive.
Zircon
refractories are equally at home combating a wide range of molten metals
and slags in steel plants, ferrous and non-ferrous foundries and are
particularly beneficial in contact with molten aluminium. It had been
used successfully for the hearths of aluminium furnaces to melt high
purity or low alloy metals. Its low wetting characteristics and high
resistance makes it an ideal refractory for the ‘belly band’ above and
below the metal line in secondary aluminium melting. There is also some
evidence to suggest that zircon can reduce the age-old problem of corundum
build up.
A
zircon paint coating is compatible with many types of aluminium/silica
refractories including castables and chemically bonded ramming mixes. In
the foundry industry zircon/alumina refractories have been used to line
and repair melting furnaces, ladles, launders, nozzles and tundishes. A
spray coating of zircon paint will encapsulate ceramic fibre linings thus
sealing and protecting ceramic fibre linings from breakdown and dust
during use.
The
use of such products in the conjunction with zircon paint enable and
induction furnace to be lined, top to bottom, by varying the consistency
from a low moisture ram mix to a mouldable patch thus avoiding the awkward
interface between lining and capping, which can cause problems. The low
thermal expansion of zircon and its excellent slag resistance makes it
ideal for coating ingot moulds in casting machines for precious metals and
centrifugal casting moulds for special steels.
The
company has recently introduced a high purity white alumina kiln paint
which is proving successful for painting kiln cars used for biscuit and
glost ware in the potteries industry. |
