| In recent years,w(Al2O3)in slag gradually increases with the large use of imported iron ore.At the same time,in order to protect the lining of blast furnace,vanadium titanium ore is generally used to protect the furnace,which causes that the slag contains a small amount of TiO2.The change of slag composition leads to the change of metallurgical properties of slag.Therefore,the quantitative study on the metallurgical properties of CaO-SiO2-MgOAl2O3-TiO2 slag system is not only of theoretical value,but also of practical significance.In this paper,the metallurgical properties of CaO-SiO2-MgO-Al2O3-TiO2 slag system were studied.The slag samples were prepared by analyzing pure chemical reagents.The viscosity of slag was measured by RTW melt physical property tester.According to the standardized definition of melting temperature and the stability index of slag,the melting temperature and stability of slag were calculated.The effects of slag composition on slag viscosity,melting temperature,stability,desulfurization ability and structure were investigated by XRD and FTIR.At the same time,according to the experimental viscosity data and the data in the literature,the parameters of Urbain model were modified,and the viscosity prediction model suitable for CaO-SiO2-MgO-Al2O3-TiO2 slag system was established.The research results are as follows.(1)When w(TiO2)is 2.2%and w(Al2O3)is fixed,with the increase of basicity(R)and magnesium aluminum ratio(w(MgO)/w(Al2O3)=M/A),the degree of polymerization of slag decreases and the viscosity presents a downward trend.However,with the increase of M/A,the change of slag viscosity is relatively gentle.It can be seen that the effect of R on slag viscosity is more obvious.When w(TiO2)is 2.2%,R and M/A are fixed,with the increase of w(Al2O3),the degree of polymerization and viscosity of slag increase.When w(Al2O3)is 13%,R is 1.25 and M/A is 0.55,the viscosity value of slag reaches the minimum,which is 0.22 Pa·s.Compared with the addition without TiO2(w(TiO2)=0%),the addition of TiO2(w(TiO2)=2.2%)will make the slag viscous.(2)When w(TiO2)is 2.2%and w(Al2O3)changes in the range of 13%-17%,the stability of slag almost remains unchanged and the average value of 1/Δη is about 7.97.When w(TiO2)is 2.2%and w(Al2O3)is fixed,with the increase of R and M/A,the stability of slag becomes better.When R increases from 1.15 to 1.25,the average value of 1/Δη increased from 7.50 to 9.15.When M/A changes from 0.45 to 0.55,slag stability is positively correlated with M/A,and the average value of 1/Δη gradually increased from 7.49 to 8.46.(3)When w(TiO2)is 2.2%and R is fixed,with the increase of w(Al2O3)and M/A,the melting temperature increases.When w(Al2O3)increases from 13%to 17%,the melting temperature of slag increases from 1349℃ to 1396℃,which increases by 47℃.When M/A increases from 0.45 to 0.55,the maximum change of melting temperature of slag is 23℃.Therefore,the melting temperature of slag is affected more by w(Al2O3).When w(TiO2)is 2.2%,w(Al2O3)and M/A are fixed,R increases from 1.15 to 1.25,the melting temperature first decreases and then increases.The addition of TiO2 will reduce the melting temperature of slag.The melting temperature of the samples was reduced by 22℃,8℃ and 15℃respectively under R=1.15,1.20 and 1.25.(4)When w(TiO2)is 2.2%,w(Al2O3)and M/A are fixed,with the increase of R,w[S]equilibrium gradually decreases,and the distribution coefficient Ls of sulfur gradually increases,that is the desulfurization ability of slag increases.When w(TiO2)is 2.2%,w(Al2O3)and R are fixed,which is similar to the effect of R on desulfurization,increasing M/A can reduce w[S]equilibrium,increase sulfur distribution coefficient LS,and improve desulfurization capacity of slag.Increasing R and M/A can enhance the desulfurization capacity of slag,but the effect of R on the desulfurization capacity of slag is significantly higher than that of M/A.When w(TiO2)is 2.2%,R and M/A are fixed,w[S]equilibrim increases with the increase of w(Al2O3),and the distribution coefficient LS of sulfur decreases,indicating that the desulfurization capacity of slag decreases.Compared with the addition without TiO2(w(TiO2)=0%),the sulfur distribution coefficient LS and desulfurization rate of slag with TiO2(w(TiO2)=2.2%)are lower,that is the addition of TiO2 is not conducive to improve the desulfurization ability of slag.(5)Using R5((X(CaO)+X(MgO)+2X(TiO2))/(2X(SiO2)+3X(Al2O3)))and N(X(MgO)/3X(Al2O3))as model parameters,the established IUM model(Improved Urbain Model)has good applicability for CaO-SiO2-Al2O3-MgO-TiO2 slag system,and its relative error is only 10%,which is far lower than the required 35%,indicating that the IUM model has high reliability.According to the calculation data of IUM model,the iso viscosity diagram of CaO-SiO2-15%Al2O3-MgO-2.5%TiO2 system is drawn.The viscosity center of slag is between R=0.77-1.39 and M/A=0-1.37,and its viscosity value is 0.3Pa·s,and the viscosity increases gradually from the center to the outside.The viscosity of slag with different composition was calculated,and the influence of M/A and R on slag viscosity was discussed.The results show that the predicted and experimental values of viscosity decrease with the increase M/A and R.At the same time,the predicted value is close to the experimental value,and the error is very small,which indicates that the IUM model is suitable for CaO-SiO2Al2O3-MgO-TiO2 slag system. |
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