Refractory Technology
Quartz is

Converted to tridymite on firing between 870 to 1470°C
Transformed to crystoballite on heating above 1470°C
All of these
Stable form of silica upto 870°C

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Refractory Technology
Carbon refractories

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

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