How to choose suitable EAF gunning mix

In the production process of electric furnace steelmaking, it is a very common method to improve the service life of electric furnace refractory linings by optimizing gunning repair materials. Generally, the aggregate material in the gunning material is the same as the material of the gunning furnace lining. With the development of metallurgical furnace lining quality, the material of gunning material has also changed from silicon, high aluminum, and magnesium to high aluminum silicon carbide, magnesium dolomite, aluminum-magnesium, magnesium-carbon, aluminum-magnesium-carbon, Magnesium calcium carbonaceous development. Both at home and abroad are committed to the development of new materials and varieties to meet the needs of the development of gunning technology for different metallurgical furnaces.

During the smelting process, the EAF gunning material is subjected to the same high temperature and harsh working environment as the repaired furnace lining. Therefore, the electric furnace gunning material should not only have high fire resistance, corrosion resistance, erosion resistance, spalling resistance, etc., but also the furnace lining has good adhesion.

The EAF gunning materials for electric furnaces include magnesia, magnesia-dolomite, magnesia-chromite, magnesia-carbon, magnesia-dolomite-carbon, etc., and part of the high-activity seawater magnesia is used in the aggregate. To promote sintering and improve the density and strength of the gunning layer. In order to make the gunning material solidify quickly during the gunning operation, and at the same time adhere to the furnace lining, a small amount of additives are often added to the aggregate.

① When adding Al, Mg and other low-melting metal powders for gunning, the metal powder's oxidation heat will increase the temperature, and harmless oxides will be formed in the gunning material to improve the adhesion between the gunning layer and the furnace lining.

②Add spinel Cr2O3, SiC, B4C, etc. to improve the oxidation resistance and corrosion resistance of the material.

③Add a small amount of organic fibers with a length of 1~5mm, which will melt at low temperature to form an air duct, which is conducive to the evaporation of water in the binder and prevents bursting.

④Add 0.1~2mm, 10~40mm long metal fiber, used in the tap hole and other parts to improve the corrosion resistance of the gunning layer.

⑤Add part of the slag of the metallurgical furnace to improve the adhesion and corrosion resistance of the gunning material.