含铌铁水中碳和硅的氧化规律

为了研究铌在铁水吹氧冶炼过程中的氧化规律,在中频炉内进行了加入碱度分别为0.538和1.5的CaOSiO2-Al2O3系造渣剂和不加渣的含铌铁水底吹氧气的冶炼试验。铁水温度为1 550℃时,研究了含铌铁水中硅、碳和铌的氧化规律,并利用FactSage软件进行了不同温度与不同碱度的造渣剂和无渣氧化铁水中各元素的热力学平衡计算。结果表明,高温吹炼使铁水中的碳优先于铁水中的硅氧化,而低温吹炼则促进铁水中硅优先于碳氧化;降低造渣剂碱度促进铁水中碳氧化、抑制硅氧化,碳和硅的氧化转化温度为1 490℃;在吹氧冶炼终点,加入碱度为1.5的造渣剂,铁水中硅质量分数下降到0.138%时,铌开始氧化减少,而加入碱度为0.538的造渣剂,铁水中碳质量分数下降到0.61%,硅质量分数升高到0.56%,铌质量分数不变,因此含铌铁水可通过加入低碱度造渣剂高温吹氧冶炼为含铌钢水。

Oxidation of carbon and silicon in Nb-bearing hot metal

In order to investigate the oxidation pattern of the Nb in Nb-bearing hot metal， the oxidizing relation among Si， C and Nb in the hot metal at 1 550 ℃ was studied by the bottom-blown oxygen atmosphere in an intermediate frequency furnace with no slag or CaO-SiO2-Al2O3 slag with basicity of 0.538 or 1.5； equilibrium calculations about Si， C and other elements in the hot metal during blowing process were also carried out using FactSage software with various basicity of slag and without slag at various temperatures. The results show that C is oxidized in preference to Si in hot metal with the relatively low basicity slag at high temperature while Si is oxidized in preference to C with the high basicity slag at low temperature. The transition temperature of Si and C oxidization is 1 490 ℃. At blowing end in experiments， Nb couldn't be oxidized in the hot metal until the mass percent of Si decreases to 0.138% with the slag of basicity of 1.5. Moreover，the mass percent of Nb doesn't change when the mass percent of Si increases to 0.56% and the mass percent of C decreases to 0.61% in the case of the slag basicity of 0.538. The Nb-contained hot metal can be made to Nb-steel with low basicity slag at a high blowing temperature.