The hot air duct of the hot blast furnace includes a main pipe, a branch pipe, a surrounding pipe, a hot air outlet connecting the main pipe and the surrounding pipe, and a hot air outlet between the main pipe and the branch pipe. Sometimes the surface temperature of hot air ducts is too high or becomes red. There are even problems with bricks falling off and collapse of the lining. The refractory bricks used for lining the hot air ducts need to be pre-laid on site due to their special location. The refractory bricks used for lining are lightweight insulating layer lightweight refractory bricks and working layer refractory bricks.
The insulation layer is constructed of two or more layers of lightweight refractory bricks. The outer layer against the pipe wall is made of lightweight clay refractory bricks, and the middle layer is made of lightweight high-alumina refractory bricks or lightweight mullite refractory bricks: in the main pipe and The working layers of branch pipes and surrounding pipes are made of refractory bricks made of andalusite-mullite bricks, andalusite corundum and other materials.
Because the hot air valve has a particularly large impact force at the hot air outlet, andalusite and corundum mullite bricks are used. Ordinary high alumina bricks cannot meet the demand for high air temperatures. The piping system is complex and has different requirements. It must be equipped with corresponding refractory brick pipe lining according to the size of the furnace.
The key to using refractory bricks for hot air ducts is to have good porosity, normal temperature compressive strength, creep rate, and thermal shock resistance. Therefore, refractory material manufacturers must control the raw materials during the production process and cannot take any chances. Shoddy goods. If you think the furnace is small or under construction deadline, use refractory bricks for lining the pipes as an emergency. In order to cause unnecessary trouble later. Even repairs will not be able to make up for it. You even have to take a break and take hot supplements, which virtually increases production costs.
The key to lining refractory bricks for thermal furnace pipes is wind resistance. The creep rate, permanent change in heating line, and thermal shock resistance must pass. Generally, andalusite bricks are used, or even with andalusite bricks. Refractory clay cannot be left to chance. Strong andalusite powder must be used to meet the needs of refractory bricks for lining pipes.
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