The technical indicators of fire resistant balls are the main reference basis in the procurement process, which determines the quality of fire resistant balls. There are 7 main technical indicators for fire resistant balls, including Al2O3 content, Fe2O3 content, bulk density, porosity, room temperature compressive strength, load softening temperature, and thermal shock stability. Below, taking high aluminum fire resistant balls as an example, analyze their technical indicators.
1. Al2O3 content
The popular point of Al2O3 is the content of alumina in the refractory ball raw material, which determines other properties. Therefore, it is the main performance indicator of fire resistant balls.
According to the aluminum content, high aluminum fire resistant balls can be divided into four types: special high aluminum balls, with RQA-80% aluminum content of 80%; First level high aluminum ball, RQA-75, with an aluminum content of 75%; Secondary high aluminum ball, RQA-65, with an aluminum content of 65%; Grade III high aluminum ball, RQA-55, with an aluminum content of 55%.
2. Fe2O3 content
The Fe2O3 content refers to the content of iron oxide in the material. Unlike the Al2O3 content mentioned above, iron content is an impurity in high aluminum spheres. The lower the content, the better the product quality. In the standard, there is no clear requirement for Class III and II high aluminum fire resistant balls. The first level high aluminum fire resistant ball shall not exceed 1.8%, and the special high aluminum fire resistant ball shall not exceed 1.6%.
3. Bulk density
Volume density is the ratio of the dry mass of the fire resistant ball to the total volume, in g/cm3. Volume density mainly represents the density of the fire resistant ball. Usually, the bulk density of fire resistant balls is closely related to their porosity and mineral composition. In refractory balls, the higher the bulk density, the better the product quality. The volume density of four types of fire resistant balls is: special high aluminum balls ≥ 2.7; Grade 1 high aluminum ball ≥ 2.5; Secondary high aluminum ball ≥ 2.3; Level 3 high aluminum ball ≥ 2.1.
4. Apparent porosity
The porosity is the ratio of the volume of the open pores of the fire resistant ball to the total volume. Usually, the slag and harmful gases in the kiln corrode the fire resistant ball itself through the opening holes, so the smaller the porosity of the fire resistant ball, the better. The porosity of four types of fire resistant balls is: super high aluminum balls ≤ 22%; Level 1 high aluminum ball ≤ 24%; Secondary high aluminum ball ≤ 26%; Grade III high aluminum ball ≤ 28%.
5. Normal temperature withstand voltage value
The normal temperature pressure resistance value has a significant impact on the production, transportation, and usage performance of fire resistant balls, therefore a higher pressure resistance value is required. Its unit is expressed in KN. The room temperature pressure resistance value of four types of fire resistant balls is: ultra-high aluminum balls ≥ 25; Level 1 high aluminum ball ≥ 15; Secondary high aluminum ball ≥ 10; Level 3 high aluminum ball ≥ 8.
6. Load softening temperature
The load softening temperature of fire resistant balls refers to the temperature at which deformation occurs during use. The load softening temperature of four types of fire resistant balls is: ultra-high aluminum balls ≥ 1530 ℃; Primary high aluminum ball ≥ 1480 ℃; Secondary high aluminum ball ≥ 1450 ℃; Grade III high aluminum ball ≥ 1400 ℃.
7. Thermal shock stability
Thermal shock stability is the ability of refractory balls to resist sudden changes in cold and hot temperatures. The performance indicators of fire resistant balls are usually expressed in terms of number of times under water cooling conditions of 1100 ℃. The thermal shock stability of four types of fire resistant balls is: ultra-high aluminum balls ≥ 10 times; Level 1 high aluminum ball, Level 2 high aluminum ball, Level 3 high aluminum ball ≥ 15 times
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