Refractories for blast furnace
The refractory materials mainly used in blast furnace ironmaking are unshaped refractory materials, carbon refractory materials, clay bricks, high alumina bricks and so on. Among them, carbon refractory materials include graphite bricks, semi-graphite bricks, carbon bricks, and Si3N4 bonded SiC bricks.
Different parts of the blast furnace are used in different environments, and the requirements and selection of refractory materials are also different.
Furnace throat: mainly use high-quality clay bricks and high-alumina bricks for masonry.
Furnace body: The temperature range of the middle and upper part is 400°C~800°C. At present, this part is made of high-quality clay bricks or high-alumina bricks.
The lower part of the blast furnace shaft: After a large number of investigations on the blast furnace, the results show that about 23% of the blast furnaces are made of SiC refractories. The anti-erosion performance of Si3N4 combined with SiC bricks developed in my country has been significantly improved, and has been applied to the masonry of major blast furnace bodies in my country, which has significantly improved the service life of blast furnaces.
Furnace waist: The temperature during normal operation is 1400℃~1600℃. In view of the erosion and serious erosion of the furnace waist, my country has developed Si3N4 combined with SiC bricks. Practice has proved that this kind of brick has erosion resistance and erosion resistance. good.
Hearth: The temperature of the lower charge is about 1600℃~1650℃, and a large amount of intermediate slag is formed and starts to drip. In China, silicon carbide bricks made of carbon refractory materials are generally used. There are also many refractory materials selected for this part abroad. The 3662m3 blast furnace belly of the Dutch Hogwen Steel Company is built with semi-graphite bricks, and the effect is better.
Hearth: The temperature is generally between 1450°C and 1500°C. The temperature in the tuyere area can reach 1700°C~2000°C. Mainly use charcoal brick masonry. In recent years, many domestic blast furnace hearths have adopted carbonaceous material-ceramic material composite structures from the French SAVOIE Company and the Japanese Electrode Company.
Iron mouth: The main device in the iron mouth is the iron mouth sleeve, which is made of cast steel and welded to the furnace shell. At present, carbon bricks with excellent performance are mainly used in this part.