Answer :
Final answer:
Silica refractories are not used in coke oven walls, beehive coke ovens, the dome and upper portion of B.F. stoves, and the open hearth furnace roof due to their poor resistance to chemical attack and limited resistance to high temperatures and chemical reactions.
Explanation:
Silica refractories are a type of refractory material that is made from silica (SiO2) as the main component. They have high resistance to thermal shock and are commonly used in various high-temperature applications. However, there are certain areas where silica refractories are not suitable or not used.
One such area is in coke oven walls. Coke ovens are used in the production of coke, a fuel derived from coal. The walls of coke ovens are exposed to extremely high temperatures and corrosive gases. Silica refractories have poor resistance to chemical attack by the gases produced during the coking process, making them unsuitable for use in coke oven walls.
Another area where silica refractories are not used is in beehive coke ovens. Beehive coke ovens are a type of traditional coke oven design that is no longer widely used. Similar to coke oven walls, the corrosive gases and high temperatures in beehive coke ovens make silica refractories unsuitable for this application.
Silica refractories are also not used in the dome and upper portion of B.F. (blast furnace) stoves. B.F. stoves are used in the ironmaking process and require refractory materials that can withstand high temperatures and chemical reactions. Silica refractories have limited resistance to the chemical reactions that occur in the B.F. stoves, making them unsuitable for use in the dome and upper portion.
Lastly, silica refractories are not used in the open hearth furnace roof. Open hearth furnaces are used for steelmaking and require refractory materials that can withstand the high temperatures and chemical reactions involved. Silica refractories have limited resistance to the chemical reactions in the open hearth furnace, particularly in the roof area.
In summary, silica refractories are not used in coke oven walls, beehive coke ovens, the dome and upper portion of B.F. stoves, and the open hearth furnace roof due to their poor resistance to chemical attack and limited resistance to high temperatures and chemical reactions.
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