| In recent years,more and more high alumina ore was used in the production process with the increase of imported iron-ore,which has a series of adverse effects on the production of blast furnace.As we know,magnesia in high alumina slags not only helps to improve the viscosity of slag but also is beneficial to desulfurization reaction.However,too much magnesia can make the slag melting temperature too high,it is difficult to meet the requirements of smelting.Therefore,it is necessary to study the effect of proper w(MgO)/w(Al2O3)on the metallurgical properties of slag.In this paper,the effects of w(MgO)/w(Al2O3)on the slag viscosity,fluidity,the melting temperature and the desulfurization capability were studied.Determination different ratio of w(MgO)/w(Al2O3)of slags viscosity and fluidity and get the melting temperature by the picture of ?-T,and desulphurization experiment was carried out with the iron content.Furthermore,a prediction model of viscosity based on Urbain model was established.The following observations were obtained in this study:(1)With w(MgO)/w(Al2O3)decreasing,viscosity increases with basicity(R)= 1.15 and same Al2O3 content.When temperature is 1500?,viscosities of different composition slags in this study are similar,i.e,about 0.3Pa s with R = 1.20 and same Al2O3 content.As a result,the higher w(MgO)/w(Al2O3),the smaller viscosity of slag.(2)At 1500?,viscosity of different composition slags increase with Al2O3 content increasing,when R is 1.10 and w(MgO)/w(Al2O3)is 0.25,i.e.,viscosity obviously increases from 0.35Pa·s increasing to 0.48Pa·s.With Al2O3 content increasing,viscosities of different composition slags are similar at 1500? when R is 1.20 and w(MgO)/w(Al2O3)is same.(3)With basicity increasing,viscosity of slag decreases with fixed w(MgO)/w(Al2O3)and Al2O3 content.Viscosities of three group slags with R = 1.05,1.10 and 1.15 respectively are very similar.However,viscosity of slag obviously decreases,When R increases to 1.20.(4)With the increase of w(MgO)/w(Al2O3),melting temperature decreases with fixed Al2O3 content when R is 1.05 and 1.10 respectively.With Al2O3 content increasing,melting temperature increases with fixed w(MgO)/w(Al2O3).However,with w(MgO)/w(Al2O3)increasing,melting temperature increases with fixed Al2O3 content when R is 1.15 and 1.20,respectively.(5)With w(MgO)/w(Al2O3)increasing,liquidity index increased when R is 1.05 and Al2O3 content is 15%,i.e.,liquidity get better.With Al2O3 content increasing,liquidity index decreases when R is 1.05 and w(MgO)/w(Al2O3)is 0.35,i.e.,liquidity get worse.(6)A revised Urbain model(Re-Urbain model)was used for prediction the viscosity of CaO-SiO2-MgO-Al2O3 quaternary slag in this study.The results show that Re-Urbain model is of low relative error and suitable for predicting the viscosity of blast furnace slag.(7)In the slag with w(MgO)/w(Al2O3)=0.35 and w(Al2O3)=15%has a good desulfurization rate along with R=1.20.In the slag with(Al2O3)=15%and R=1.20 has a good desulfurization rate along with w(MgO)/w(Al2O3)=0.35.These factors are caused by changes in the slag viscosity reduction,and speed up the slag desulfurization rate.In summary,the high Al2O3 content slag has high viscosity,poor fluidity,high melting temperature and poor desulphurization ability.Addiction MgO into the slag is beneficial to improve the metallurgical performance of the blast furnace slag with high Al2O3 content.The achievements in this paper can provide theoretical guidance for the rational use of MgO,which is beneficial to optimize the sintering process and blast furnace smelting process. |
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