Investigation On Interfacial Reaction Between Multicomponent Slag And MgO-C Refractories

MgO-C refractories are commonly used in the lining of converters and LF refining furnaces due to its high slag resistance.In this paper,the wetting,permeation and erosion behaviors of molten multicomponent slag and MgO-C refractory are investigated by the sessile drop method using ultra-vacuum high temperature wetting test system,which explores the reaction mechanism of interfacial wetting and penetration between multicomponent slag and MgO-C refractory.The investigation between the interface reaction behavior of four component slag(CaO-SiO2-Al2O3-MgO)and MgO-C refractories are founded that:with the increase of carbon content,the final equilibrium wetting angle increases gradually,the starting and ending temperature of reaction decrease gradually,and the reaction time to reach equilibrium gradually increases.When the carbon content in the substrate is 16%,the final equilibrium wetting angle of 1#(R=1)and 2#(R=3)slag are greater than 90°,which indicate that the slag are not wetting.There is high reaction temperature during low carbon content,Si,Ca,and Al elements in the slag along the crack and pore channels permeate into the substrate generating low melting point CAS and CAS2.According to Yu Zhongda penetration theory,lower liquid viscosity and smaller wetting angle result in lower permeability coefficient K and higher permeability driving force ? P,which accelerate the penetration of slag into the substrate.There is a lower reaction temperature during higher carbon content,and the value of the wetting angle is larger,which leads to an increase in the permeability coefficient K,K2>K1>K3,and the permeability driving force ?P value is smaller or even negative.At the same time,MA,MS and CA6 high melting point compounds are generated,which block the penetration channel of slag,alleviating slag erosion on the substrate and prolong service life.The investigation between the interface reaction behavior of five component(CaO-SiO2-Al2O3-MgO-Fe2O3)slag and MgO-C refractories are founded that:with the increase of carbon content,the final equilibrium wetting angle increases gradually,but all showed a wetting state.The starting and ending temperature of the wetting reaction decrease gradually,the reaction time to reach equilibrium gradually increases,and the white metal particle Fe appears at the reaction interface between the slag sample and the substrate.There is high reaction temperature during low carbon content,Si,and Ca elements in the slag through the crack and pore channels to permeate into the substrate to generate low melting point CMS,which result in a lower liquid phase viscosity and a smaller wetting angle.According to Yu Zhongda penetration theory,lower liquid viscosity and smaller wetting angle can result in lower permeability coefficient K and higher permeability driving force ?P,which accelerate the penetration of slag into the substrate.There is a lower reaction temperature during higher carbon content,and the value of the wetting angle is larger,which leads to an increase in the permeability coefficient K,K6?K5?K4,and the permeability driving force ?P value is smaller or even negative.At the same time,C2S and M2S high melting point solid solution are formed to block the permeation channel of the slag,which result in the carbon reduction reaction at the reaction interface is avoided,the erosion of the slag on the substrate is alleviated,and the MgO-C substrate is protected.