Study On The Influence Of Crystallization On The Metallurgical Behavior Of LF Refining Slag

The slag amount of high alkalinity refining slag significantly affects the precipitation of high-melting mineral phase,and its physicochemical properties affect the slag fluidity,deoxidation and desulfurization and the ability to adsorb inclusions,which seriously affect the quality of molten steel.In this paper,the crystallization process of different components of refining slag was studied by differential thermal analysis method.According to the results of Factsage simulation,the viscosity of typical samples was tested by molybdenum wire hanging slag method in laboratory,and the process of viscosity decrease with temperature was analyzed.The variation law of the slag sample was calculated by combining the viscosity-temperture curve.The dynamic crystallization process of the refining slag was observed in real time by the hot wire method.The research results provided some theories for optimizing the composition of the high alkalinity refining slag guide.The following conclusions were obtained:The viscosity of the refining slag is increasing with the decrease of temperature.The refining slag at R=6:the viscosity value at 1490? is 0.726Pa·S,the temperature at the viscosity is 3Pa.S is 1436?,the melting temperature is1501?;When R=6 of the refining slag,adding 5%B₂O₃ or 7%CaF₂ can reduce the viscosity of the refining slag,lower the melting temperature,improve the fluidity of the refining slag,and improve the melting efficiency.Through differential thermal analysis,it can be concluded that the refining slags with different alkalinity,different MgO content,different Al₂O₃content and different CaF₂ content will have different degrees of exothermic peaks at different temperatures with the decrease of temperature,?C₂S?Ca₃Al₂O₆?Ca₃MgAl₄O₁₀?Ca₁₂Al₁₄F₂O₃₂and CaAl₂O₄ started to precipitate in turn.The crystallization kinetics of Avrami refining slag shows that the increase of alkalinity and MgO content of refining slag increases the crystallization rate of refining slag and promotes the crystallization behavior of refining salg;The increase of Al₂O₃content and CaF₂ content of the refining slag reduces the crystallization reaction rate of the refining slag and inhibits the crystallization behavior of the refining slag;the growth mode of the crystal is two-dimensional growth or three-dimensional growth.When the crystallization process of refining slag is studied by hot wire method,the incubation time of the crystal is gradually shortened with the increase of cooling rate,shortening from 74s to 60s,and the crystallization starting temperature is lowered from 1535? to 1506?,which means that when the cooling rate is higher than When low,the refining slag requires a long incubation time to gradually form crystals.Figure28;Table12;Reference 65...