含铌铁水预处理脱硅保铌的研究

 为防止铁水预处理脱硅过程中脱铌，通过中频感应电炉底吹氧气冶炼含铌铁水，研究了铁水预处理吹氧过程中不加渣和加入造渣剂吹炼过程中脱硅保铌的行为及铁水中各元素含量的变化规律。试验结果表明：在铁水温度1623K加入碱度为4的CaO-SiO2-CaF2的造渣剂、供氧强度为0. 5m3/(t·min)时吹氧冶炼，铁水中的硅含量降低到0. 012%(质量分数，下同)时，铌才开始氧化，脱硫率为83%，磷含量不变；在相同的温度和供氧强度，不加造渣剂吹炼时，铁水中的硅降低至0. 16%时，铌开始氧化，硫和磷含量不变；有渣吹炼脱硅保铌终点硅含量是无渣吹炼脱硅保铌终点硅含量的10%，显著脱硫。

Study on Desiliconization and Niobium Conservation in Nb-Containing Hot Metal Pretreatment

To prevent niobium from extracting from the hot metal during desiliconization of hot metal pretreatment, the behavior of desiliconization and niobium-conservation as well as variations of elements in hot metal with time was studied in Nb-bearing hot metal pretreatment in an intermediate frequency induction electric furnace with bottom-blowing oxygen device. The experimental results show that Nb begins to oxidize and removes from the molten iron when the content of silicon decreases to 0. 012%, the content of phosphorus is not changed and the desulfurization ratio is up to 83% under the conditions of the molten iron smelted at 1623K, blown oxygen at 0. 5m3/(t·min) and covered with a CaO-SiO2-CaF2 slag system in which the basicaty indux of the slag is 4. 0; However, in the non-slag experiments with the same factor of oxygen supply intensity ［0. 5m3/(t·min)］ and the smelted temperature (1623K), the content of niobium of the hot molten don′t begin to decrease until the silicon in hot metal reduce to 0. 16%, and the sulfur and phosphorus of the hot molten don′t change with the other elements with time in the bottom-blowing oxygen process. So the content of silicon in hot iron in blowing end in the slag smelted process is about 10% of the content of silicon with no slag condition and the desulfurization in the process with the slag is more significant than that with no-slag smelted method.