How To Improve The Load Software And Heat Shock Resistance Function Of Red Stone Refractory Bricks?

How to improve the load software and heat shock resistance function of red stone refractory bricks?


Skill requirements for red based stone bricks in hot blast stoves

As a high-temperature structural material, hot blast stove bricks have very strict requirements for high-temperature creep rate. Red stone, like silicon wire stone, has excellent high-temperature structural strength function. Table 1 presents a functional comparison between red stone and refractory products such as mullite, bauxite, and corundum. From Table 1, it can be seen that the high-temperature creep rate of redstone bricks is better than that of alumina, corundum, and most mullite bricks. Redstone is one of the ideal raw materials for low creep refractory materials.

South Africa, which is rich in red stone, uses red stone low creep bricks in the middle and upper parts of the hot blast stove.

A foreign company used red based low creep bricks (referred to as red based stone bricks) in the upper and middle upper parts of hot blast furnaces when undertaking projects such as Wuhan Iron and Steel, Taiyuan Iron and Steel, * * Steel, Tangshan Iron and Steel, and Ansteel. This brick has strict requirements for chemical composition, especially TiO2 and R20. TiO2 is not greater than 0.5% or 0 6%, R2O not exceeding 0.6%, and controlling R2O+impurities not exceeding 1.2%.

In recent years, various steel companies in China have added thermal shock resistance targets to the lining materials of newly built hot blast stoves, in addition to the above objectives. The thermal shock stability has been tested for 20, 25, or 30 times; The Al2O3 content increased to 65% in addition to 53% and 57%; The creep temperature increased from 1350 ℃ and 1400 ℃ to 1450 ℃ and 1500 ℃. Overall, the skill requirements are higher and the physical and chemical goals are more stringent than similar foreign products.

The above indicates that red based low creep bricks will become increasingly popular among people. In addition, it has the characteristics of small volume expansion, resistance to sudden temperature changes, good thermal shock stability, and good corrosion resistance during high-temperature processes, which will also have broad prospects in other fields.
The Effect of Red Cornerstone or Red Cornerstone Composite on the Load Softening Temperature and Other Functions of Refractory Brick Products

This brick is similar to the production process of high alumina bricks, using high alumina alumina or corundum or mullite as aggregates, adding a series of red stone stones, and investigating the variation rules of the load softening temperature and creep rate of the product.

Red stone stone concentrate is produced in Xiuyan County, Liaoning Province: Al2O3 56.71%, Fe2O3 0.75%, TiO2 0.08%, R2O 0.56%.

It is evident from Table 3 that as the amount of red stone increases, the load softening temperature of the product also rises. When the increase in red cornerstone is 15%, the load softening temperature reaches around 1600 ℃.

In high alumina refractory materials, the addition of red stone or red stone composite additives achieves high high-temperature structural strength values. Based on our research and experimental assignments, it can be concluded that when the red stone concentrate is increased by 15% -20%, 25% -30%, the load softening temperature of high alumina products is expected to reach 1600 ℃ or 1700 ℃, but there may be slight differences due to differences in the composition of high alumina product aggregates and matrices.

The softening temperature and creep deformation under load are important targets for the application of refractory materials, and the deformation and even collapse of furnace lining during use are closely related to these properties. Adding red stone or a composite of red stone and silicon wire stone can achieve good results in high alumina refractory materials.

Enhance the thermal shock resistance of red stone materials

Adding red stones can create many fine voids that disperse thermal stress. Figure 2 shows the microstructure of the matrix of red based stone bricks with a creep temperature of 1450 ℃. The characteristic of the microstructure in this field of view is the generation of mullite by the reaction of red stone, and closed pores at the micrometer level can be seen inside and between mullite crystals. The intragranular pores are less than 1-2 μ m, while the intergranular pores are 3-9 μ m long and 0.5-1 μ m wide.

We know that the cracking of refractory materials is caused by the thermal expansion and contraction caused by heating and cooling of refractory materials, and the stress generated inside the refractory material exceeds the arranged elastic boundary. The many fine pores formed by the reaction of the red stone allow the stress generated inside the refractory material due to thermal expansion and contraction to be released, thereby improving the material's heat shock resistance.

Red stone with high TiO2 content, such as Meixian red stone in China with TiO2 content of about 2.5%, is more conducive to the high thermal shock resistance of the material. Its mechanism is related to the reduction of the elastic modulus (E) of the red stone and the formation of low swelling mineral deposits of aluminum titanate (AT). The coefficient of linear expansion (α) and elastic modulus (E) are inversely proportional to the thermal shock resistance factor (R) of the data.