At present, corundum mullite bricks are one of the main products for blast furnace ceramic cups. At present, this product still has some quality defects in terms of performance. The main manifestation is that the product has serious missing edges and corners during the grinding and masonry process, which affects the quality of the product. Masonry quality. Through the improvement of this project, it can be ensured that the quality qualification rate of the product will increase by 2%, and it can successfully pass the customer’s quality acceptance, improve the quality reputation, and further increase the market share of the product.
1. Analyze the reasons
Corundum mullite bricks have serious missing edges and corners during the grinding and laying process. The analyzed reasons are as follows:
1. Hardness. Hardness is generally considered an important indicator of a material’s wear resistance. The harder the material, the better its wear resistance, but in the case of large impact wear, the impact of hardness is not necessarily very large. Refractory bricks are heterogeneous and the hardness of each part may be different. For refractory bricks containing corundum and silicon carbide, if the bonding strength is sufficient, these high-hardness materials can still resist the wear of the refractory bricks after the low-hardness and easy-to-wear materials wear away.
2. Crystal structure and crystal solubility. Materials with a specific crystal structure have better wear resistance. For example, cobalt with a close-packed hexagonal structure has a small friction coefficient and is wear-resistant. Metallurgically speaking, metals with poor mutual solubility also have good wear resistance.
3. Strength. Refractory bricks will encounter a lot of impact wear during use. Therefore, high-strength refractory bricks have strong resistance to wear.
4. Volume density. Refractory bricks with high volume density and low apparent porosity have high wear resistance.
5. Temperature. Temperature affects the hardness, solubility and reactivity of materials, thus indirectly affecting the wear resistance of refractory bricks. Generally, as the temperature increases, the mutual solubility and reactivity increase. Refractory bricks are used at high temperatures, and their wear resistance at high temperatures is very important.
6. Atmosphere. Similar to the effect of temperature, the atmosphere affects the mutual solubility and reactivity between materials, thereby affecting their wear resistance.
2. Technical key and project implementation content
Targeted transformation of the product formula system in view of the above factors: in the production process of the product, through reasonable particle gradation and the selection and use of high-quality aggregates, the density of the bricks is increased; the firing temperature is optimized to improve the product The physical and chemical properties and wear-resistant strength ensure the quality of the later grinding and masonry processing of the product, thereby ensuring the improvement of the quality of the pre-masonry of the product.
1) Use high-quality raw materials: Better-quality alumina-grade raw materials and brown corundum raw materials are used as aggregates to ensure high hardness of the material and increase the toughness of the refractory material without increasing the cost.
2) Increase the proportion of brown corundum fine powder in the matrix fine powder, and at the same time add alumina fine powder to reduce the porosity of the product after firing and increase the product density.
3) Change the traditional product stacking method and add air inlets for kiln car stacking to make the firing temperature more uniform.
4) Increase the product sintering temperature so that the product is fully sintered and the internal materials are fully integrated and mutually soluble.