In the production process of EAF steelmaking, it is a very common method to improve the service life of EAF refractory lining by spraying repair material. Generally, the material of the aggregate in the spray filler is the same as the material of the furnace lining under the spray filler. With the development of the lining quality of metallurgical furnace, the material of spray supplement has also been developed from siliceous, high aluminum, magnesium to high aluminum silicon carbide, magnesium dolomite, aluminum magnesium, magnesium carbon, aluminum magnesium carbon, magnesium calcium carbon. Both at home and abroad are committed to the development of new materials and new varieties to meet the needs of the development of different metallurgical furnace spraying technology.

The spray filler is subjected to the same high temperature and harsh working environment as the mended lining in the smelting process, so the spray filler should have high fire resistance, erosion resistance, erosion resistance, peeling resistance, etc., but also must have good adhesion with the mended lining.

There are magnesia, magnesia - dolomite, magnesia - chromite, magnesia - carbon, magnesia - dolomite - carbon, etc., and some highly active seawater magnesia is used in the aggregate to promote sintering and improve the density and strength of the spray coating. In order to make the spray-fed material solidify quickly during the spray-fed operation and adhere to the furnace lining at the same time, a small amount of additives are often added to the aggregate.

① When adding Al, Mg and other low melting point metal powder, metal powder oxidation and heat release help to increase the temperature, and form harmless oxides in the spray supplement, improve the adhesion between the spray supplement layer and the furnace lining.

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

③ Add a small amount of 1~5mm long organic fiber, melt at low temperature to form a vent, which is conducive to the evaporation of water in the binder and prevent bursting.

④ Add 0.1~2mm, 10~40mm long metal fiber for the steel outlet and other parts to improve the corrosion resistance of the spray coating.

⑤ Add part of the slag of the metallurgical furnace to improve the adhesion and corrosion resistance of the spray supplement.