Material Optimization And Performance Improvement Of Anhydrous Gun Mud

With the development of the blast furnace towards the direction of large scale and longevity,the blasting clay has changed from the simple expendable refractory to functional refractory.In order to further improve the operation performance of stemming and high temperature performance,this paper attempts to optimize the stemming material,magnesium olivine,fused magnesia,quartz sand as aggregate,introducing stemming respectively discusses forsterite,fused magnesia,quartz sand of anhydrous stemming job performance,mechanical property,the influence of sintering performance and high temperature performance and the mechanism of action.The effects of silicon metal powder,sodium bentonite and alumina powder on the working performance,mechanical performance,sintering performance and high-temperature service performance of anhydrous blasting clay were studied.The optimum amount of silicon powder was found.The results show that:1)The solid iron in magnesium peridot can promote the sintering of gun mud.The gun mud with magnesium peridot as the aggregate has low expansion coefficient,high mechanical strength and plasticity meeting the requirements.Therefore,it is feasible for magnesium peridot to replace bauxite in the anhydrous gun mud.After calcined at 1450℃,the bending strength and compressive strength of shotcrete were 3MPa and 13 MPa respectively,the volume density was 1.940 g·cm^-3,and the apparent porosity was 21.4%.2)50%electrofused magnesia with aggregate can improve the mechanical strength of shotcrete at room temperature.Bauxite and electrofused magnesia can produce a large amount of magnesia and alumina spinel at high temperature.Magnesia and alumina spinel have large volume density,uniform structure,stable quality and strong anti-erosion ability.After roasting at 1450℃,the flexural strength and compressive strength of the shotcrete were increased to 2 MPa and 8 MPa respectively.Therefore,it is feasible to replace 50%bauxite in anhydrous shotcrete with fused magnesite.3)Replacing all the alumina clinker in the shotcrete with quartz sand can improve the mechanical properties of the shotcrete at room temperature,increase the volume density and reduce the apparent porosity.Si O₂in the quartz sand and a large number of carbon materials in the gun-mud composition,under the action of high temperature reduction reaction occurs,forming part of silicon carbide.When the calcined temperature was 1450℃,the bending strength reached 3 MPa,the compressive strength reached 8 MPa,the volume density reached 1.986 g·cm^-3,and the porosity dropped to 27%.Therefore,it is feasible to replace all bauxite in the cannon mud with quartz sand.4)The addition of silicon metal powder as an additive to the blasting mud can improve the bending strength,compressive strength and volume density of the blasting mud,and reduce the apparent porosity.Silicon carbide is produced by the combination of silicon metal powder and carbon materials in the blasting mud at high temperature.Sodium bentonite can improve the plasticity of shotcrete,but sodium bentonite has high expansion coefficient,low strength after heat treatment and high porosity.After calcined with alumina powder,a large amount of mullite is produced,with large volume expansion,small volume density,and high porosity and linear change rate.5)Add 7%silicon metal powder to fully sintered in the gun mud to generate a large number of silicon carbide whiskers,improve the gun mud’s bending strength and volume density,reduce the porosity rate of the gun mud,and have an appropriate line change rate and high temperature bending strength.After calcined at 1450℃,the compressive strength of shotcrete was 10.45 MPa,the volume density was 2.105g·cm^-3,and the apparent porosity was 25.2%.