Numerical Simulation On Migration Of Titanium Compound In Blast Furnace Hearth For Titanium-bearing Wire Injection

In order to reduce production cost and improve competitiveness of steel companies,blast furnace long-campaign has been paid more attention.Refractory of blast furnace hearth is in high-temperature state for a long term and easily to be eroded by the flow of hot metal and slag.Production practices have shown that the erosion of hearth is the limiting element of long-campaign.At present,it is widely used to inject titanium-bearing materiel through partial tuyeres to protect the erosion area of hearth.But some blast furnace did not achieve the goal,research about the migration of titanium in hot metal is not sufficient.Based on the fluid dynamics software,this research takes a blast furnace as model,builds a three-dimensional hearth model and calculates the migration path of titanium compound with different injection parameters and furnace conditions.A preliminary relationship between the titanium distribution and furnace protection has been discussed.The conclusions are as follows.(1)The migration path and concentration distribution of titanium compound in hot metal vary widely with different injection positions.When titanium-bearing wire is injected through the tuyere which located away from the taphole,titanium compound would distribute both at the sidewall and bottom of hearth.It's conducive to maintaining the corresponding erosion area.When injected through the tuyere near the taphole,only the sidewall of hearth could be protected.The maximum of titanium compound in "elephant foot" erosion area of hearth differs several ten times with different injection positions.It is conductive to achieving good results if the erosion area locates away from the taphole.There exists a deviation for injection position and maximum of titanium compound in the curve of "elephant foot".With the increase of ?,the deviation decreases.The optimum position should be determined by calculation results under comprehensive consideration about the location of erosion area and taphole.(2)When injecting titanium-bearing wire in the same position for different injection amounts,concentration of titanium compound correspondingly changes,but the migration path is the same.When initial concentrate are 0.3%and 0.6%,the maximum concentrations locate in the same area in the curve of "elephant foot" erosion area,and the values are in proportion of initial concentrates.(3)In tapping process,with,the decline of slag-iron interface,the distribution range of titanium increases,and maximum of concentrate in "elephant foot" erosion area will deviate.The deviation depends on injection position,and it is obvious when injection position is near the notch.The migration path of titanium compound varies little for different floating heights of deadman.When the floating heights are 0 m,0.3 m and 0.6 m,the difference of titanium compound distribution is not obvious under the condition of this research.On the whole,tapping process has little effect on the protection of hearth,and the protection range in later period will be larger than that in earlier period.(4)The permeability of blast furnace hearth has a significant effect on migration of titanium compound.In this calculation condition,the maximum of titanium compound in the curve of"elephant foot" has double difference for different porosities of deadman,and the positions of maximum concentrate vary up to 25°.The hearth should be kept a good permeability in the process of furnace protection.(5)Mud package has a certain effect on the distribution of titanium compound,and with the change of injection position and tapholes,the effect will be different.In production,large blast furnace can achieve good results by adjusting tapholes.If the single-notch blast furnace has been eroded near the notch,it should be considered to feed titanium ore through the top of blast furnace.