Irene,
During the manufacture of refractory materials the ingredients are
selected to achieve certain chemical and physical properties in the
finished material. Among the variables that can be controlled for are:
thermal expansion, resistance to corrosive environments, strength, and
toughness (resistance to the abrasive action of the materials that will
be in contact with the refractory during its operating life)
In addition to the variation of the chemical composition mentioned by
Killick and Young, the raw materials may also be processed for desired
physical characteristics. Selecting by grain size is a prime example
(larger grains being more slow to react). But we must also include in
this category, any materials that have been previously fired to 'grow'
certain mineral species that are highly refractory, ground up, and added
to the mix.
Thirdly, conditions during sintering (if a the product is a ceramic
shape), or during use (if the product is a castable refractory), will
influence the strength, refractoriness, and heat transfer
characteristics of these materials
A little experience is worth a thousand calculations!
for more information try:
Grimshaw, Rex W The chemistry and physics of clays and allied ceramic
materials, by Rex W. Grimshaw, New York, Wiley-Interscience [1971] 4th
ed. rev
Skip Williams
>>> [log in to unmask] 10/31/00 11:57AM >>>
Dear all,
could anyone please tell me: what properties make a clay refractory?
Many thanks, Irene
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