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Preparation & uses of silica refractories
written 7.8 years ago by | • modified 7.8 years ago |
FE > Semester 1 > Applied Chemistry 1
Marks : 04
Years : MAY 2016
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written 7.8 years ago by | • modified 7.8 years ago |
FE > Semester 1 > Applied Chemistry 1
Marks : 04
Years : MAY 2016
written 7.8 years ago by | • modified 7.8 years ago |
The main raw materials used are quartz, sand stone etc. the siliceous rock is crushed and ground with 2% lime and water to form a thick paste so formed is moulded into bricks either manually or using a machine-press after which they are heated to about $1500^\circ C$ for 24 hours. Cooling takes about 1 or 2 weeks.
During heating quartzite converts into crystobalite which during cooling gets converted into tridymite, such that silica bricks are the mixture of these two.
Uses:
• Glass furnaces
• Roofs of electric and hearth furnaces
• Lining of acid converters etc.