What are the refractory materials for the bottom of the AC EAF

 The AC EAF has a long history of steelmaking, so its refractory materials for the bottom of the furnace have also undergone changes. The bottom of the furnace is rammed with asphalt tar magnesia or brine magnesia. Because brine magnesia is eroded quickly at the bottom of the furnace, it cannot meet the requirements for use. Although asphalt tar magnesia has better durability, it is troublesome to construct and has environmental pollution. Therefore, more magnesia bricks and low-grade magnesia-carbon bricks are used to build the bottom of the furnace. The durability of the brick-built furnace bottom is very good, but the masonry is labor-intensive and time-consuming.

By the 1990s, my country began to use the furnace bottom dry ramming material. It is simple and convenient to construct, and does not need to be baked. After the construction is completed, it can be directly used for steelmaking. The material is magnesium calcium iron dry vibrating ramming material. Using the low melting point calcium ferrite it contains, when the temperature rises above 1200 °C, it can quickly sinter to produce strength. Under the hydraulic pressure of molten steel, it can rapidly sinter and shrink, the shrinkage reaches 4% to 5%, and the bulk density increases to more than 3.0 g/cm3. Has particularly good corrosion resistance and good use results. The consumption of steel per ton of refractory materials is reduced from 4 to 8 kg of asphalt magnesia bricks to less than 2 kg. Some modern EAF bottom dry materials consume as little as 0.3 kg per ton of steel, which is mainly corresponding to the steelmaking process technology; In the process of use, the material is sintered layer by layer, sintered and densified near the molten steel, resisting The erosion and scouring of molten steel, the transition layer is under the sintered layer, and the loose non-sintered layer is under it. This loose layer has low density and low thermal conductivity, which play an important role in the insulation of the EAF. After years of promotion and development, the vast majority of electric furnace bottoms in my country use this kind of ramming material.

The construction and use of the furnace bottom dry material are the key factors affecting the use effect. The bottom material should be called dry vibratory castable more appropriately. Because the vibration densification density of the material is more than 0.2g/cm3 higher than that of ramming, the erosion resistance will be significantly improved. Kairuid kiln believes that the dry material should be vibrated for construction, especially for the DC EAF bottom that is not easy to be repaired. When repairing, the slag and scrap steel at the bottom of the furnace must be cleaned up, otherwise the steel slag under the repairing material may melt when used to a certain extent, and the furnace bottom material will float up under the impact of the steel block. When tapping, the floating bottom block may block the tapping hole and affect the tapping. In the process of use, the furnace bottom should be observed at any time. When there is a floating, it should be repaired in time (generally, the same kind of material can be filled to the pit) to prevent the floating from further expansion and prevent the occurrence of steel breakout. It is worth noting that when using in the first few furnaces, due to the thin sintered layer, the ability to withstand the impact of scrap steel is weak, so light and thin materials should be added, and the feeding basket should be lowered to prevent the scrap steel from having a large impact on the bottom of the furnace.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality EAF dry ramming mix are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source:What are the refractory materials for the bottom of the AC EAF
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