Refractory materials used for blast furnace tapping and slag chute

Because of the bad working conditions of the cast iron ditch of blast furnace, it is directly washed by hot metal, so it is seriously damaged. In the selection and application of refractory materials for tap hole, it is necessary to have high temperature resistance, wear resistance, high temperature slag resistance, thermal shock resistance and oxidation resistance. On this basis, the following problems should be considered comprehensively: the particle size of sintered or fused alumina should be more than 1.5mm, which should account for more than 75% of its dosage, so as to enhance the high temperature wear resistance; silicon carbide plays the role of filling, and forms the matrix of channel material, so the particle size should be less than 3.4mm, of which the particle size less than 0.15mm should account for more than 3.4mm More than 60%; natural graphite or amorphous carbon can be used as carbon containing material, and the particle size should be less than 0.3mm.
The ramming material made of coke, clay and asphalt is used in the tapping ditch of medium and small blast furnace, which has low service life and strong smell. It is better to gradually use high alumina clinker "silicon carbide" graphite ramming material (or castable).
Al2O3-SiC-C low porosity high density castable is imported from abroad for a large blast furnace (volume 4063m3) of a steel plant. The main raw materials are dense fused corundum, silicon carbide, adding a small amount of metal silicon, metal aluminum powder and a certain amount of accelerator and gel remover. In order to study the castable for blast furnace tap hole, brown corundum was used as the main material, and SiC, carbonaceous material, clay, high alumina cement, superfine powder and additives were properly mixed to make the castable. The proportion of brown corundum was 60 ~ 80%, SiC was 10 ~ 30%, clay was 1 ~ 5%, high alumina cement was 2 ~ 5%, superfine powder was 1 ~ 15%, and additive was 0.3 ~ 1.0%. The castable has the advantages of easy to obtain raw materials, low cost, convenient construction and long service life. Table 1 shows the refractory materials used for the tap hole of blast furnace.
The lining of the slag line and hot metal line of the blast furnace runner is damaged quickly, especially when the ratio of slag to iron is high. Therefore, hot gunning method can be used to repair the trench lining, so as to achieve balanced damage and improve service life.