CaO-SiO2-FeO-Cr2O3-MgO-MnO渣系物相组成的热力学计算

摘要：在含铬铁水转炉冶炼过程中，Cr很容易被氧化成Cr2O3进入渣中，并与渣中其他成分反应生成高熔点含铬尖晶石。采用FactSage热力学软件计算了CaO-SiO2-FeO-Cr2O3-MgO-MnO转炉渣系在冶炼温度1300～1700℃下的物相组成，研究了Cr2O3、FeO和碱度对炉渣中尖晶石相含量的影响规律。研究结果表明，温度和渣系成分都会影响炉渣的物相组成。渣系中含有Cr2O3时，物相中均含有MgCr2O4、FeCr2O4和MgFe2O4尖晶石相，尖晶石相的总含量随着Cr2O3和碱度的增加而增加，随着炉温的升高而减少。温度为1300～1500℃时，炉渣中尖晶石含量随着FeO的增加而增加；温度为1500～1700℃时，尖晶石含量随着FeO的增加而略有减少。在温度小于1500℃的转炉冶炼前中期，炉渣物相组成中尖晶石相所占比例较大，易造成化渣不良或者炉渣粘稠，影响转炉冶炼工艺的顺行。

Thermodynamic calculation of phase composition of CaO SiO2 FeO Cr2O3 MgO MnO slag system

During the smelting process of chrome containing hot metal in converter, Cr is easily oxidized into Cr2O3 entering the slag and reacted with other components in the slag to form a high melting chrome containing spinel. Phase compositions of the CaO-SiO2-FeO Cr2O3-MgO-MnO slags in converter at the temperature range of 1300-1700℃ were calculated by thermodynamic software FactSage. The effects of Cr2O3, FeO and basicity on the content of spinel were studied. The calculation results show that both temperature and slags composition affect the phase composition of the slags. When the slags systems contain Cr2O3, the phases will consist of MgCr2O4, FeCr2O4 and MgFe2O4 spinel phases. The content of spinel phase increases with the increasing of Cr2O3 and basicity, and decreases with the increasing of temperature. When the temperature is in the range of 1300-1500℃, the spinel content in the slag increases with the increasing of FeO. When the temperature is in the range of 1500-1700℃, the spinel content decreases slightly with the increasing of FeO. In the early and middle stage of the converter process which the temperature is less than 1500℃, the proportion of spinel phase in the slag phase compositions is large, which is easy to cause the viscosity of slags increasing and bad operation conditions of converter.