Refractory Technology
Carbon refractories

Do not burn/oxidise, when exposed to air on heating
Do not resist temperature fluctuations
Are not attacked by slags, as they are not wetted by melts
Have extremely low thermal & electrical conductivities

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Refractory Technology
Natural silica

Mainly contains quartz
Is not stable at high temperature
All of these
Transforms to other allotropic forms i.e tridymite and cristoballite involving very high volume changes

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