The blast furnace is the "heart" of steel production. It consists of five parts: the throat, the body, the waist, the belly and the hearth. Each part has its own unique working environment and demand for refractory materials. First, understand the working principle of each part of the blast furnace and recommend suitable refractory materials.
1. Throat
The throat is the feed port of the blast furnace, which mainly bears the impact and wear of the charge, and is also subject to high temperature and chemical erosion. The charge is added from the top of the furnace, falls to the throat by gravity, and then enters the body. At the throat, the charge will react with the rising coal gas.
Refractory recommendations: high alumina refractory bricks, corundum bricks. These materials have high strength, high wear resistance and good corrosion resistance. They can withstand the impact and wear of the charge, while resisting high temperature and chemical erosion.
2. Furnace body
The furnace body is the main reaction area of the blast furnace, with a temperature of more than 1500℃, and is also subject to wear and tear of the charge and erosion of coal gas. In the furnace body, iron ore and coke undergo a reduction reaction to generate molten iron and slag. At the same time, the coal gas exchanges heat with the charge during the ascent.
Silicon carbide bricks and silicon nitride combined with silicon carbide bricks are recommended as refractory materials. These materials have good high-temperature stability, high thermal conductivity and wear resistance, and can withstand high temperatures and wear of the charge, while ensuring heat transfer and reaction.
3. Furnace waist
The furnace waist connects the furnace body and the furnace belly, and plays a role in regulating the distribution of coal gas and supporting the furnace body. The diameter of the furnace waist is usually smaller than that of the furnace body and the furnace belly, which increases the flow rate of coal gas at the furnace waist, thereby promoting the contact and reaction between coal gas and the charge.
Magnesium aluminum spinel bricks and dolomite refractory bricks are recommended as refractory materials. These materials have good high-temperature stability and corrosion resistance, can withstand high temperatures and the scouring of coal gas, and ensure the stability of the furnace body.
4. Furnace belly
The furnace belly is the reduction area of the blast furnace, the temperature is also very high, and it is also eroded and scour by slag. In the furnace belly, the iron ore is further reduced to molten iron, and a large amount of carbon monoxide gas is produced.
Magnesia bricks and magnesia-chrome bricks are recommended for refractory materials. These materials have good high temperature stability, corrosion resistance and thermal shock stability, can withstand high temperature and slag erosion, and ensure the reduction reaction.
5. Furnace hearth
The furnace hearth is the storage area of the blast furnace, which stores high-temperature molten iron and slag, and needs to withstand high temperature, high pressure and chemical erosion. The molten iron and slag are layered in the furnace hearth and discharged regularly through the iron outlet and slag outlet.
Carbon refractory bricks and graphite bricks are recommended for refractory materials. These materials have good high temperature stability, thermal conductivity and corrosion resistance, can withstand high temperature, high pressure and chemical erosion, and ensure the smooth discharge of molten iron and slag.
The selection of refractory materials for various parts of the blast furnace needs to be comprehensively considered according to the specific working environment and requirements. In practical applications, timely maintenance and replacement are also required according to the operation of the blast furnace and the loss of refractory materials to ensure the normal operation and production efficiency of the blast furnace.
