Corundum mullite bricks are one of the main products of blast furnace ceramic cups. At present, there are still some quality defects in the performance of this product. The main manifestation is that the product is seriously missing edges and corners during the grinding process, which affects the masonry quality of the product.
1. Analysis of reasons
Corundum mullite bricks are seriously missing edges and corners during the grinding process. The reasons for analysis are:
1. Hardness. It is generally believed that hardness is an important indicator for measuring the wear resistance of materials. The harder the material, the better its wear resistance, but in the case of great impact wear, the hardness effect is not necessarily very large. Refractory bricks are inhomogeneous bodies, and the hardness of each part may be different. For refractory bricks containing corundum and silicon carbide, if the bonding strength is sufficient, when the hard and easy-to-wear materials with low hardness are worn, these high-hardness materials can still resist the wear of refractory bricks.
2. Crystal structure and crystal miscibility. Materials with a certain specific crystal structure have better wear resistance, such as cobalt with a close-packed hexagonal structure, which has a small friction coefficient and is wear-resistant. The wear resistance between metals with poor metallurgical solubility is also good.
3. Strength. Refractory bricks will encounter a lot of impact wear during use, so high-strength refractory bricks have strong wear resistance.
4. Bulk density. Refractory bricks with high bulk density and low apparent porosity have high wear resistance.
5. Temperature. Temperature affects the hardness, solubility and reactivity of materials, and thus indirectly affects the wear resistance of refractory bricks. Generally, as the temperature increases, the solubility and reactivity increase. Corundum mullite bricks are used at high temperatures, and wear resistance at high temperatures is very important.
6. Atmosphere. Similar to the influence of temperature, the atmosphere affects the solubility and reactivity between materials, thereby affecting their wear resistance.
In view of the above factors, the product formula system is transformed in a targeted manner: in the production process of this product, the density of the brick is improved through reasonable particle grading and the selection and use of high-quality aggregates; the firing temperature is optimized and increased, the physical and chemical properties and wear resistance of the product are improved, and the quality of the later grinding and masonry processing of the product is ensured, thereby ensuring the improvement of the quality of the pre-masonry of the product.
1) Use high-quality raw materials: high-quality alumina-grade raw materials and brown corundum raw materials are used as aggregates to ensure the high hardness of the material, increase the toughness of the refractory material, and will not increase the cost.
2) Increase the proportion of brown corundum fine powder in the matrix fine powder, and at the same time increase alumina micropowder to reduce the porosity of the product after firing and increase the density of the product.
3) Change the traditional product stacking method, increase the air inlet holes of the kiln car stacking, and make the firing temperature more uniform.
4) Increase the firing temperature of the product to fully sinter the product and fully combine and dissolve the internal materials.
