The blast furnace is divided into furnace throat, furnace body, furnace waist, furnace belly, hearth and furnace bottom from top to bottom.
Furnace throat is the part that is directly impacted and rubbed when the charge falls. Generally, high-density and high-alumina bricks are used. The temperature of the upper and middle parts of the furnace is only 400~800 Celsius, and high alumina bricks and sillimanite bricks are used for this part. The lower part of the furnace body requires high-quality clay bricks, high-alumina bricks, silicon carbide bricks or corundum with high slag resistance, alkali resistance, high temperature resistance, and high wear resistance due to the high temperature and the erosion of dust and alkali metal vapor. brick. The temperature of the furnace side reaches 1400~1600 Celsius, and the slag erosion and steam erosion are serious, and the erosion and corrosion are strong. Therefore, silicon carbide bricks and reaction-bonded silicon carbide bricks are used.
The furnace belly temperature reaches 1600~1650 Celsius, and high alumina bricks, corundum bricks or silicon carbide bricks can be used. The temperature of the upper part of the hearth near the tuyere is 1700~2000 Celsius, and sillimanite bricks, corundum castables, graphite fillers, and silicon carbide refractory bricks are mostly used. The bottom temperature of the furnace is 1450~1500 Celsius. Graphite bricks and microporous carbon bricks are mostly used. Now corundum bricks, corundum mullite bricks and synthetic mullite bricks are also used.