Research And Application Of High-purity Al₂O₃-MgO Castables

The main material of the aluminum spinel pouring material is the easy to produce the flake Alumina magnesia castable in the use of the process to form spinel reaction matrix more dense,can effectively inhibit the slag and molten steel erosion and infiltration,reduce the spall thickness and increase the thermal shock performance and improve the service life.In this paper,we mainly explored linear change rate,bulk density,apparent porosity,slag resistance and flexural and compressive strength and other properties of castable by changing change the content of matrix magnesia,silicon powder and spinel under different processing conditions.The results show:(1)MgO fine powder can be added in the Al Mg casting,and can promote the sintering of the materials..Add 3%MgO fine powder,volume density of 3.10g/cm3 and apparent porosity,rate reached 16.53%;compressive strength is 263 MPa,flexural strength of 43.9 MPa,heavy firing line changes 0.01%;adding amount of MgO more than 3%,volume density between the2.97~3.06g/cm3;apparent porosity of 17.40~19.14%;resistance pressure degree in 129~187MPa in the range,the flexural strength in 26.3~37.7 MPa range;heavy firing line changes0.05~0.12%.Thus it may be known,the MgO content of more than 3%,material linear change rate and apparent porosity rate is too high,cause the material to loose organizational structure,reducing the castable compressive and flexural strength,and material corrosion resistance to slag greatly weakened.The fused magnesia suitable amount was 3%.(2)Adding 10% of spinel,sample volume density,anti bending and compressive strength are compared with adding 20% high,heavy materials burn line changes of the former was lower than that in the latter;adding spinel sample volume density,anti rupture and crushing than adding magnesium oxide high;adding magnesium oxide specimen anti slag corrosion resistance than add pre synthesized spinel,but slag permeability was significantly higher than that of adding spinel.(3)In silicon powder adding quantity is less,rate of uncertain expansion specimens line,increase the overall trend of bulk density,apparent porosity reduces the overall trend,the flexural strength and compressive strength increase,enhanced slag resistance.But with the silicon powder adding increasing amounts of continue,each performance index of the specimens decreased.Comprehensive consideration,the best addition amount 0.5% for silicon powder.With low cement castable trial with AM integral narrow slit type permeable brick inSwitzerland 70 tons of steel ladle on the service test,results show that the low cement bond quality AM water permeable brick used in ladle effect is better than the same period the application of chrome corundum slit purging plug.The experimental results showed that,by using permeable brick of high purity AM castable production can meet the Rui steel ladle argon blowing process.