【作者】 龙防；

【导师】 周国凡；

【作者基本信息】 武汉科技大学 ， 钢铁冶金， 2006， 硕士

【摘要】 目前我国高炉炼铁生产为了降低成本而大力开展精料和节能降耗技术,增加了进口高Al₂O₃矿配比,从而引起高炉炉渣中Al₂O₃含量进一步增大,超过了传统概念上的“15%”的界限,某些高炉有时甚至超过了20%,对高炉冶炼造成了较大的影响。本文通过实验室实验对高Al₂O₃矿冶炼进行了系统研究。实验采用武钢原、燃料条件。从烧结过程开始,研究了不同含量Al₂O₃对烧结矿转鼓强度、还原度、低温还原粉化率及软熔性能的影响;通过对烧结矿的显微结构观察研究Al₂O₃含量对烧结矿SFCA生成的影响;依照武钢现场炉渣成分配料进行实验,分析Al₂O₃、MgO及碱度这三个因素对炉渣粘度、熔点和脱硫性能的影响。研究结果为扩大高Al₂O₃矿配比提供了理论依据和实验基础。研究得出:在实验条件下,烧结矿中Al₂O₃含量从1.71%增加到的2.24%,烧结矿转鼓强度在Al₂O₃含量为1.89%左右最大;Al₂O₃含量对还原度影响不是很明显,而对烧结矿低温还原粉化率的影响特别显著,随着Al₂O₃含量的升高,烧结矿低温还原粉化率明显增加;软熔性能,Al₂O₃是针状铁酸钙生成的必要条件。在高Al₂O₃含量的高炉炉渣中,Al₂O₃含量越高,炉渣粘度越大,熔点愈高,脱硫能力降低;适当增加MgO含量可以降低炉渣粘度、熔点和熔化性温度,提高炉渣脱硫能力,但其含量最高不超过12%;炉渣碱度在1.0～2.0之间变化时,高碱度炉渣能够降低炉渣粘度,但其热稳定性较差,适宜碱度在1.17左右;炉渣中加入少量CaF₂时,可以显著降低炉渣粘度和熔点,改善其稳定性。为了解决高Al₂O₃炉渣粘度过高,脱硫能力低的问题,可以采取诸如改善焦炭质量,适当提高渣比、喷煤比,使用高风温等措施,也可以通过优化配矿结构适当增加渣中MgO的含量。而MgO含量的增加可以通过在烧结过程或球团矿内添加菱镁矿或白云石的方法实现,但烧结矿中MgO的含量不应超过4%,球团矿不超过3%。更多还原

【Abstract】 At present,in order to reduce the cost of ironmaking in blast furnace,lots of iron and steel enterprises are vigorously unfolding the technology of beneficiated material and energy conservation。So they increased the propotion of import ore,which with high content of Al₂O₃。Accordingly the content of Al₂O₃ in BF slag farther increased and it goes beyond the limit of“15%”,even over“20%”in some BFs sometimes,which badly impact the BF smelting。In this article,I systemicly study the influence to ironmaking by high content of Al₂O₃ ore with experiment in lab。The experiment adopt the raw material and fuel condition of Wuhan Iron and Steel Company。It started from sintering process,researched the impact on the sintering ore’s resistance to tumbling,reductiondegree,low temperature breakdown index and soft heat nature by differ content of Al₂O₃。With the medium of microstructure observation to study the content of Al₂O₃ impact on the agglomerate SFCA’s indigenous;In accordance with Wuhan Iron and Steel Company’s scene slag composition to mix experimentize,to analyses the impact on BF slag’viscosity, melting point and desulphurizing ability by the three factors of Al₂O₃,MgO and alkalinity。The result of the research supply theory gist and experiment foundation to enlarge the content of high Al₂O₃ mine。Experimental result as follows:at the experiment condition,with the content of Al₂O₃ in the sintering ore increasing from 1.71% to 2.24%,agglomerate resistance to tumbling is maximal at the content of Al₂O₃ about 1.89%,and it is not evident that the impact on reductiondegree by the content of Al₂O₃,but give notable influence on low temperature breakdown index,which increase rapidly with the increased content of Al₂O₃。And Al₂O₃ is the essential condition of the creation of needle-shaped calcium ferrite。In the BF slag of high content of Al₂O₃ ,the more Al₂O₃ in slag,the higher slag viscosity,melting point and lower desulphurizing ability is;propriety content of MgO could depress the slag viscosity ,melting point and rise the desulphurizing ability ,but it’s content shoudn’t exceed 12% ;the slag alkalinity changed from 1.1 to 1.2,high alkalinity slag can depress slag viscosity,but it’s thermostability is less,it’s propriety alkalinity is at about 1.17。It can visibility depress the slag viscosity and melting point,improve slag’s fastness with adding a few CaF2。In order to solve the problem of high slag viscosity and low desulphurizing ability resulting by high content of Al₂O₃ in slag,some countermeasures such as improving the coke quality,propriety rising the slag ratio,coal ratio and using high wind-temperature can be adopted,and it also can be optimized the rate of slag with increasing the content of MgO,and the increasing of MgO can be realized by adding magnesite or dolomite through the sintering process or in the pellet,but the content can’t exceed 4% in sintering ore and 3% in pellet。更多还原