| Firstly this article determines the damaged causes through damaged analysisof the slag wall after used,and then starting from the following aspects:particle sizedistribution,different particle size and the amount of spinel,selectionof binder and dispersant,influence of additives on the microstructure of materials,theslag wall of corundum-spinel has been conducted systemical research.(1)Based on the basic situation of slag wall used by Wisco at present,thisexperiment analysis its physical indexes,and the cause for damage is analyzed.Theresults show that:at present,the Wisco is using slag wall owning higher porosity,lowerstrength,and after high temperature processed there is large volume expansion,this isvery unfavorable for the slag resistance properties of materials.Microstructureanalysis of samples after used is also verified the main reasons of damage is erosionand penetration of slag,the slag line’s damage is very serious, due to slag and materialchemical erosion,lead to large amount of liquid phase,high temperature damage effectof liquid phase is very large, continuous erosion to inner material dissolved.Causedstructure spalling in constant erosion of molten steel, lead to collapse finaly.(2)Through the analysis of present defects of slag wall,we first begin with highaluminium material system,through the change of q value,studying the different effectof granularity on performance of the conventional castables.The results showthat:when q is0.27,the flow value is the highest,material to the most compact,volumedensity and strength of samples is higher,and lower apparent porosity.(3)As the basis of high aluminum material system,studied the influence forconventional physical properties,thermal shockstability and slag resistance of thespinel of different size.Research shows that:adding spinel has little effect onthe physical properties of materials,for the improvement of thermal shock resistanceand slag resistance performance is favorable.When aggregate:powder=15:5,samplehas excellent thermal shock stability and slag resistance.Through the establishmentof slag/refractory corrosion thermodynamics model,found that corundumspinel materials under high temperature mainly through the reaction of aggregatesurface and MgO of the slag to form spinel isolation layer,preventing slag on thematerial further dissolution. And after static slag resistance test of the sample ofaggregate:powder=15:5,the observation of microstructure also verify the thermodynamic simulation situation.(4)Adding ρ-Al2O3makes the material system"pure",greatly improves hightemperature strength of the material and slag resistance performance;but ρ-Al2O3bound sample’s early strength is low,and is not conducive to retaining wall hangingand installation,therefore on the basis of ρ-Al2O3addition is3%,adding lower content’scement to improve the normal temperature strength of slag wall,and samples of simplyρ-Al2O3as binder are compared,find that when ρ-Al2O3addition is3%,the contentof cement addition is1%,the normal temperature strength of material not only has hugestrength and low porosity,but also its the slag resistance and high temperaturestrength also do not fall;the analysis by XRD and the microstructure after slagresistance test,find that a little amount of cement addition do not produce toomuch liquid phase in the material,instead being added to a certain amount to generateCA6(high melting point phase),which is advantageous for the high temperaturestrength of the material and slag resistance improved.After confirmed theρ-Al2O3-cement composite combination system,studied the influence of three kindsof dispersants on the rheological behavior of slurry castable matrix.The results showthat:FS60through the synergistic effect of electrostatic repulsion and sterichindrance,greatly reducing the viscosity of the paste,with addition of FS60slurry,shearthinning,when adding amount of0.1%,excellent dispersion of the slurry,meeting therequirements of construction.(5)Thermal dynamic calculation and analysis of XRD both show that,withincreasing MZ content,make the amount of spinel formation raise,resulting in the hightemperature treatment line change rate and apparent porosity increase,the normaltemperature strength and bulk density decrease,falling slag penetration ability.At thesame time,due to the presence of ZrO2,thermal shock stability of material is improvedby the martensitic transformation toughening,but once the amount is too large,thermalshock stability decline.Thus,the appropriate MZ addition can improve the thermalshock stability and the slag corrosion penetration of material,overall performance ismore appropriate when MZ content is1%.(6)Through the thermal dynamics software simulation results show:Y2O3intothe corundum-spinel slag wall,without the addition of SiO2,mainly existed in thesystem of high temperature phase is spinel and corundum phase,the thermal dynamiccalculation,Y2O3and A2O3generating extremely easy to Y3Al5O12at1500℃(YAG),YAG with physical excellent chemical properties is advantageousfor the flexural strength improved materials at high temperature.At the same time,Y2O3particles possesses greater activity,uniformly distributed in the material matrix, promote sintering,increase the density of material,Y2O3reacts with Al2O3inmolten slag into Y3Al5O12,Y3Al5O12is high melting point phase,these high meltingpoint phase diffuse specimen internal with liquid,the solid content of liquidphase increases gradually,viscosity gradually increases,wetting degree of slagand wall between is lower,thereby inhibiting the further penetrationof slag.Comprehensive performance,we use the Y2O3added2%more appropriate. |
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