Refractory materials for hot blast furnace body

March 29, 2019

In order to achieve high blast temperature, in addition to the operating conditions of the blast furnace, the high-temperature heat source, the structure of the hot blast stove and other factors, the hot blast stove must have refractory materials that can not only withstand high temperatures for a long time, but also meet the technological requirements of the hot blast furnace as a guarantee. The refractory materials of the hot blast stove should be able to withstand high temperature and high pressure, have good creep resistance at high temperature. The brick has large heat capacity and good thermal conductivity, which is favorable for heat exchange and improvement of air temperature. The choice of refractory materials for hot blast stoves is mainly determined by the hot air temperature. When the hot air temperature is lower than 900℃, clay bricks are generally used. When the wind temperature is higher than 900℃, the lining and checker bricks in the tempering part are made of high alumina bricks, mullite bricks, sillimanite bricks and silica bricks.

Refractory materials for hot blast furnace body

The operating conditions and damage characteristics of various parts in the hot blast stove are different, and the requirements for physical and chemical properties of the refractory materials used are also different. The bricks for hot blast stoves can be basically divided into two parts: high temperature zone and medium and low temperature zone. The bricks used in the temperature zone include: the upper brick of the combustion chamber, the upper lattice brick of the regenerator, the upper large wall brick, and the top brick. The medium and low temperature brick area includes: the middle and lower bricks of the combustion chamber, the middle and lower lattice bricks of the regenerator, the middle and lower large wall bricks, and the bricks for each outlet.

The medium and low temperature area uses a large amount of bricks, accounting for about two-thirds of the total bricks used in the hot blast furnace. This part can be used to compare dense clay bricks or high alumina bricks. Due to the difference in production operation and air temperature, the requirements for physical and chemical properties of refractory bricks are also different. For example, special attention should be paid to the thermal stability of the top brick to prevent the brick from being peeled off or broken due to sudden temperature changes; the upper part of the combustion chamber and the regenerator is required to have high-temperature structural strength, the lower re-firing line Shrinkage, good slag resistance, etc., to prevent high temperature deformation of the combustion chamber, tilting and collapse of the lattice bricks, grid holes and so on. The grid brick also requires good thermal conductivity, large heat capacity, and fast heat absorption and heat release. These requirements should be based on the wind temperature level of the hot blast furnace.