碳饱和铁水中TiC/N析出热力学研究

摘要：高炉原料中添加一定量的含钛原料是有效延长高炉寿命的方法之一，钛溶解度与温度间热力学关系是指导含钛铁水有效护炉的理论依据。以某钢厂生铁和商业钛铁合金为原料，制备得到含钛铁液，利用高温共聚焦显微镜（CSLM）进行高熔点物相TiC/N在线析出研究，从而获得铁水中钛的溶解度与温度的对应关系。研究结果表明，当生铁中钛的质量分数分别为0.31%、0.36%和0.47%时，对应的析出温度分别为1715.1、1745.1和1814.1K。氮分压为105Pa时，钛的质量分数分别为0.07%、0.11%和0.25%的铁液中TiC/N析出温度分别为1535.6、1594.3和1729.8K。得到熔融生铁中，钛的活度系数与TiC析出温度之间的关系式；同理，氮分压为105Pa时，得到了钛的活度系数与温度间的关系式。

TiC/N precipitation thermodynamics in carbon saturated molten pig iron

Adding a certain amount of titanium bearing iron ores in the blast furnace raw materials is one of the methods to effectively extend the life of the blast furnace. The thermodynamic relationship between titanium solubility and temperature is the theoretical basis for guiding the effective protection of titanium containing molten pig iron. The pig iron of a steel plant and commercial ferrotitanium alloy were used as raw materials to prepare titanium containing molten pig iron. In situ observation of the formation of the high melting point phase TiC/N was carried out by high temperature confocal scanning laser microscopy to obtain the relationship between titanium solubility in molten pig iron and temperature. The results show that when the titanium contents in pig iron are 0.31%, 0.36% and 0.47%, the corresponding precipitation temperatures are 1715.1K, 1745.1K and 1814.1K, respectively. When the nitrogen partial pressure is 105Pa， the precipitation temperatures of TiC/N in the molten pig iron with the titanium contents of 0.07%, 0.11% and 0.25% are 1535.6K, 1594.3K and 1729.8K, respectively. The relationship between the activity coefficient of Ti and the precipitation temperature of TiC in the molten pig iron is obtained. In the same way, when the nitrogen partial pressure is 105Pa, the relationship between the activity coefficient of Ti and the temperature is obtained.