MgO含量对CaO-Al_2O_3-MgO-Fe_xO-SiO_2-K_2O系熔体性质的影响

Influence of MgO content on the thermo-physical properties of CaO-Al_2O_3-MgO-Fe_xO-SiO_2-K_2O slags

研究了MgO含量变化对CaO-Al_2O_3-MgO-Fe_xO-SiO_2-K_2O系熔体黏度和熔化特性的影响,结合X射线衍射和扫描电镜分析熔渣冷却过程中的物相析出,并通过Fact Sage软件计算了该体系的黏度、熔点和冷却过程中析出相的含量与温度的关系,并与实验结果进行了对比和分析.结果表明,MgO含量的增多会造成熔渣熔化温度的升高,黏度随温度变化时会出现黏度骤增的转折点,高于转折点温度时,熔渣黏度随MgO含量变化不大,同时该转折点温度随MgO含量的增加而升高.在熔渣冷却过程中析出相主要为固溶的橄榄石相和Fe3O4尖晶石相,MgO含量的增大可以促进橄榄石相的析出,熔体黏度骤增主要由于橄榄石相的析出造成的.

The effects of MgO content on the viscosity and melting behaviors of CaO-Al2O3- MgO-FexO-SiO2- K2O slags were studied. The slag samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM） to identify precip- itated phases during the cooling process. Meanwhile, theoretical calculations on the viscosities, solidus/liquidus temperatures as well as quantities of various precipitated phases from the slag system were also carried out by using the FactSage software, which were com- pared with the experimental results. The results indicate that the addition of MgO in slag could cause the increase of melting tempera- ture. The relation between viscosities and temperature presents a breakpoint where the viscosity has a rapid rise, and above this transi- tion temperature, MgO content has little effect on the viscosity. The transition temperature increases with the increasing of MgO con- tent. In the process of slag cooling, the crystalline phases are mainly composed of olivine and spinel. From the calculation results, it could be found that the addition of MgO enhances the precipitates of olivine, which makes the viscosity increase suddenly.