The application of refractory bricks in kilns is common, because it has better high temperature resistance and wear resistance. However, if the bricks are damaged, it will affect its performance and cause damage to the kiln. Production has caused some impact, so what are the factors that lead to its damage?
1. Physical factors
1. Refractory brick cracks caused by drastic temperature changes.
2. High temperature melting caused by too high temperature.
3. Shrinkage or expansion after reheating will cause damage to the furnace body and shorten the service life of refractory bricks.
4. Improper oven, excessive heating, excessive thermal expansion, destroying the furnace body and shortening the life of refractory bricks.
5. The liquid metal penetrates into the refractory brick through the obvious pores of the refractory brick, or penetrates into the cracks of the brick, and after condensing into a solid state, the volume expands, stress is generated, and the brick breaks up.
2. Chemical factors
1. Chemical attack of molten slag (including chemical attack of molten furnace dust).is generally the main factor for the corrosion of the refractory brick lining of the smelting furnace.
2. Chemical corrosion of furnace gas.mainly refers to the gradual oxidative corrosion in the oxidizing furnace gas at high temperature.
3.mutual chemical corrosion between refractory bricks
If acidic and alkaline refractory bricks are mixed together, fusible compounds will be formed at the contact point at high temperature, causing both to be corroded at the same time.
4. Electrochemical erosion.
The anode (zinc) of a copper-zinc battery. Continuously being oxidized and corroded, the principle of electrochemical erosion of carbon refractory bricks is the same. In high-temperature smelting furnaces (such as oxygen steelmaking converters), when carbon-containing refractory bricks (such as tar-bonded bricks) are mixed with other refractory bricks, batteries may be formed. The molten slag is equivalent to the electrolyte, and the carbon-containing refractory brick becomes the anode, and the refractory brick is destroyed due to carbon oxidation.
3.mechanical factors
1. When adding materials, especially heavy metal materials, the mechanical impact on the furnace bottom and furnace wall is an important cause of brick cracking.
2. The flow of liquid metal (such as the electromagnetic stirring of the molten metal in the induction melting furnace) causes mechanical wear on the inner surface of the furnace lining.
3. The high-temperature furnace vault is damaged due to excessive extrusion force, which causes the inner side of the refractory brick to soften, deform.
During the production of refractory bricks, attention should be paid to the preparation of raw materials, and the temperature and humidity of the production should be controlled. In addition, pay attention to the correct construction method when using it to reduce the damage rate of the bricks and increase the utilization rate.
