Liquid Phase Behavior Of FeO_x-siO₂-cao-MgO-Al₂O₃ System

By studying the effects of MgO content,basicity and oxygen partial pressure on the liquid phase behavior of FeO_x-SiO₂-CaO-MgO-Al₂O₃ system during heating process,the phase change process of the system under different MgO content,basicity and oxygen partial pressure at different temperatures were described.Among them,the reaction history of FeO_x-SiO₂-CaO-MgO-Al₂O₃ system during the heating process was analyzed by synchronous thermal analyzer?TG-DTA?,and the starting temperature of the precursor compound was determined.The phase evolution law of the reaction process was analyzed by in-situ XRD.After combining with the liquid phase generation property test,FactSage software simulation and SEM-EDS,the conclusions are summarized as follows:1)Under different oxygen partial pressure conditions,the MgO content is in the range of 1.5³.0%,and the amount of liquid phase formed by the system decreases with the increase of MgO content.2)At a temperature below 1250?,the amount of liquid phase formed is the lowest when the basicity is 1.0,and the amount of liquid phase generated is the most when the basicity is 2.0.When the temperature is higher than 1250?,the amount of liquid phase formed by the system increases as the basicity increases.3)The decrease in oxygen partial pressure does not affect the difference between the basicity and the MgO content,but overall,the liquid phase production of the system is reduced to some extent.Decreasing the partial pressure of oxygen when the basicity is low is beneficial to lower the starting temperature of the liquid phase,but the amount of liquid phase decreases as the temperature increases.For sintered ore,it is not conducive to liquid phase formation when the partial pressure of oxygen is lowered to 0.001 atm.For fiux pellets and acid pellets,lowering the partial pressure of oxygen will produce a liquid phase in advance.4)When the basicity is 2.0 and 1.8,the liquid phase formation rate of the system is relatively stable,and it is slowly generated within a certain range,and has strong controllability.However,when the basicity is 1.8,the liquid phase formation temperature range is larger,which indicates that the sinter liquid phase formation property is better when the basicity is 1.8,which is more conducive to production.5)It was found by electron scanning microscopy and energy spectrum analysis that hematite greatly increased with the decrease of basicity.Magnetite increases with the increase of MgO content.It is believed that the increase of Mg²⁺will enter the magnetite crystal lattice,which will make the magnetite stable and difficult to be oxidized.Fig.49;Table 9;Reference 55.