Density Calculation Model Of SiO 2 -Al 2 O 3 -CaO-MgO-'FeO'-'Fe 2 O 3 'multi-component Slag System

Density is one of the important physical properties for molten slags.It not only has important influence on the separation of metal and slag,slag foaming,mass transmission,and settling velocity of molten steel in metallurgical reaction process,but also has important value for calculation of thermodynamic function and discussion of melt structure.Although there are many calculation models for slag density at home and abroad,most of these models have some problems,such as,large errors,narrow components and temperature range,complex computation process and the need for thermodynamic software.Consequently,these models has been greatly restricted in practical applications.In present study,we had collected the density measurement data from authoritative literatures for the metallurgical slag components,SiO₂,Al₂O₃,CaO,MgO,FeO and Fe₂O₃.Next,these experimental data were strictly screened through three steps.Finally,the total of 1839 density data were obtained.The SiO₂-Al₂O₃-CaO-MgO system and SiO₂-Al₂O₃-CaO-MgO-‘Fe O'-‘Fe₂O₃'system database were established using the collected data respectively.According to the additity of the molar volume of molten slag,and combined with the different components of the database and experimental measurement of temperature density value,the SiO₂-Al₂O₃-CaO-MgO quaternary system,SiO₂-Al₂O₃-CaO-MgO multicomponent system and SiO₂-Al₂O₃-CaO-MgO-‘FeO'-‘Fe₂O₃'containing iron density calculation model were respectively developped.The model parameter was optimized in Matlab software.The measured value and calculated value were compared and the accuracy and applicability of the model were tested.The results showed that the calculated results of the model were highly consistent with the measured values.The average relative error of the model???were respectively 1.04%,1.62%,1.96%.Relative error distribution of the model were not affected by the composition,temperature and density.The model had a strong applicability to the density prediction in the range of fitting component and temperature.The calculated values of the model were compared with the experimental values under different temperatures and components ranges.The relationship between temperature and components with density for each system was deeply analyzed,and explanation of error was given.The conclusions were as follows.The density of slag constantly will decreased with the increasing the SiO₂ content.When the system contains Al₂O₃,MgO,Al₂O₃ or CaO,the density of slag decreases with the increase of Al₂O₃ and CaO content.When the content continues to increase to a critical point,the density will increase again.In the‘FeO'-‘Fe₂O₃'system,the density decreases with the increase of‘Fe₂O₃'.In silicate system,the density increases with the increase of‘FeO'and‘Fe₂O₃'content.When Al₂O₃ is used instead of‘FeO',the density will decrease.Exceot the component Al₂O₃,the density and temperature of the slag system have a linear relationship with the temperature,which always decreases with the increase of temperature.