Refractory materials for blast furnace hearth and furnace bottom

The hearth is the place where molten iron and slag are loaded. The hearth, especially the tuyere, is the area with the highest temperature in the blast furnace.

In addition to being affected by high temperature, the hearth lining is also subjected to chemical erosion and erosion of slag and iron, and the bottom of the furnace is mainly eroded by the infiltration of molten iron. Mainly garlic head and pan bottom erosion.

The refractory materials used for the hearth and the bottom of the furnace have a mixed material method and a material method. The mixed masonry is made of high alumina bricks and carbon bricks, the upper middle of the furnace bottom is made of high alumina bricks, and the furnace hearth wall, the lower layer of the furnace bottom and the surrounding area are made of carbon bricks. There is also a cushion layer of graphite ramming material rammed on the furnace bottom steel plate. Then build a second layer of carbon bricks, and then use high alumina bricks to build the working layer. One material masonry method is the full carbon brick bottom of the blast furnace hearth.

There are also many composite furnace lining ceramic cups for the hearth of large blast furnaces. The ceramic cup is a ceramic material with low thermal conductivity, which can avoid the brittle fracture zone at 800-1100°C. Ceramic mugs are highly impermeable and scour-resistant. The use effect of ceramic cups is obvious, and many manufacturers use this structure to build masonry.

At present, there are corundum prefabricated blocks with low binder content in the market for masonry. The just-pressed prefabricated blocks have low porosity, very little change in porosity distribution, and have strong thermal shock resistance. Compared with ceramic cups, corundum prefabricated blocks have higher resistance to slag erosion. Suitable for use on the upper and lower areas of ceramic mug walls.

The material of the ceramic cup is made of white corundum bricks combined with mullite and composite corundum bricks, which have become the preferred raw materials for ceramic cups. However, the method of mixing high alumina bricks and carbon bricks in small blast furnaces also occupies a considerable proportion.