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What are refractories?
"Refractory" items according to any standard English dictionary are
materials which are hard to work with, and are especially resistant to
heat and pressure. In practical terms, refractories are products used
for high temperature insulation and erosion/corrosion and are made
mainly from non-metallic minerals. They are so processed that they
become resistant to the corrosive and erosive action of hot gases,
liquids and solids at high temperatures, in various types of kilns and
furnaces.
Basalt is a naturally occurring siliceous refractory product. It was
formed many, many years ago - and is still being formed in lava flows
from volcanic eruptions - under the natural geological forces of heat
and pressure. Modern refractory production is largely a replication of
this process of forming naturally-occurring (or synthetic) non-metallic
mineral oxides (and some non-oxides like carbides or nitrides) under the
bonding conditions of high heat and pressure. Of course with
technological progress, alternative bonding techniques, such as with
chemicals, cements, resins, etc. have also developed.
Because refractory products are so resistant to heat, erosion and
corrosion, they are typically used in any process involving heat and
corrosion such as in kilns and furnaces. According to the main chemical
component, i.e. fire clay, or magnesia, or zirconia, etc. they are
commonly known as alumino-silicate or acid refractories, basic
refractories, and neutral refractory products.
In physical characteristics, refractories typically have relatively high
bulk density, high softening point (or Pyrometric Cone Equivalent), high
crushing strength. They are produced as standard bricks, or as shapes
(including hollow-wares) or as granular or unshaped or monolithic
products.
The principal applications of refractories are in iron and steel
industries, cement, glass, non-ferrous metals, petro-chemicals and
fertiliser industry, chemicals, ceramics and even thermal power stations
and incinerators.
The development and application of refractories for various industries,
testing procedures of properties and so on are covered in the English
language, by a number of well-known technical journals, such as The
Bulletin of the American Ceramic Society, Taikubutsu Overseas,
Interceram, Ceramic News, Refractories Applications, IRMA Journal,
Transaction of the Indian Ceramic Society, Metal News, etc.
Click
here to read the Milestones
of Indian Refractory Industry.
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