链箅机—回转窑制备全赤铁矿氧化球团的关键技术研究

发布时间：2018-03-10 02:02

本文选题：赤铁矿　切入点：链箅机-回转窑　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：随着高炉炉料结构发展及钢铁短流程兴起,氧化球团的需求量逐渐增加,但受磁铁矿资源限制,以赤铁矿为原料制备氧化球团逐步成为关注的焦点。然而,赤铁矿生产氧化球团存在预热温度和焙烧温度高、高温焙烧固结性能差、还原膨胀率高、回转窑易结圈等难点,因此,开展链箅机-回转窑制备全赤铁矿氧化球团的关键技术研究,对我国钢铁企业大量利用赤铁矿制备氧化球团具有重要的现实意义。由于磁铁矿资源日益短缺,我国少数链箅机-回转窑球团生产线开始配加赤铁矿生产氧化球团,当赤铁矿配加到一定程度,出现生球爆裂、粉末过多、抗压强度降低、回转窑结圈频繁等现象。本论文以国内首条全赤铁矿链箅机-回转窑200万吨/年球团工程为研究背景,解析赤铁矿制备氧化球团的难点及实施工程化应用,为我国赤铁矿球团生产提供成功范例和实践经验。系统研究了赤铁矿的成球性能、干燥预热性能及焙烧性能,确定了赤铁矿适宜的成球工艺参数、干燥预热参数及焙烧工艺参数,深入优化生球制备工艺、研发链箅机和回转窑关键技术。在链箅机-回转窑球团生产线,基于赤铁矿球团的入窑粉末更易软熔引起结圈及富氧焙烧的优势,首次研发与应用回转窑窑尾热筛新工艺减少结圈,以及应用富氧焙烧技术。赤铁矿链箅机-回转窑球团工程化应用表明,工艺流程达到集约化,物流运输累积时间为6.04min,固废资源实现减量化二次利用;热工制度优化表明,工序能耗由2013年的37.03kgce/t降为32.86kgce/t,粘结剂消耗量仅为10.3kg/t,抗压强度达2707N/P,工序能耗与南美带式焙烧机工序能耗相差不多,但链箅机-回转窑制备的氧化球团质量更优,总体投资比带式烙烧机低近20%。蛇纹石用量对赤铁矿氧化球团性能的影响表明,蛇纹石有助于赤铁矿生球性能、预热球团和焙烧球团抗压强度提高,以及还原膨胀率降低;氧化球团微观结构研究表明,在焙烧固结过程中MgO与Fe_2O_3无限固溶,促使固相扩散反应发生,从而提高氧化球团的固结强度。制备蛇纹石赤铁矿氧化球团工业试验表明,球团的原料综合成本降低35.87元/t,氧化球团的抗压强度和冶金性能得到改善;高炉配加蛇纹石氧化球团期间,铁水合格率达到99.97%,一级品率达到75.06%,铁水质量得到提高,炉渣碱度由1.14增至1.15,w(MgO)/w(Al_2O_3)上升至0.58.
[Abstract]:With the development of blast furnace charge structure and the rise of short process of iron and steel, the demand of oxidized pellets increases gradually. However, due to the limitation of magnetite resources, the preparation of oxidized pellets from hematite has gradually become the focus. The production of oxidized pellets from hematite has some difficulties, such as high preheating temperature and calcination temperature, poor consolidation performance of high temperature roasting, high reduction expansion rate, easy ring formation in rotary kiln, etc. The research on the key technology of preparing total hematite oxide pellets by grate rotary kiln has important practical significance for iron and steel enterprises in our country to make full use of hematite to prepare oxidized pellets. A few grate-rotary kiln pellets production lines in China begin to add hematite to produce oxidized pellets. When hematite is added to a certain extent, there will be balling, too much powder and lower compressive strength. In this paper, based on the research background of the first holatite grate-rotary kiln 2 million t / a pellet project in China, the difficulties in preparing oxidized pellets from hematite and its engineering application are analyzed. This paper provides a successful example and practical experience for hematite pellet production in China. The pelletizing properties, drying preheating properties and roasting properties of hematite are systematically studied, and the appropriate technological parameters of hematite pelletizing are determined. Drying preheating parameters and roasting process parameters, optimizing raw pellet preparation technology, researching and developing the key technology of grate machine and rotary kiln. Based on the advantages of hematite pellets, which are easier to be melted into the kiln and roasted by oxygen enrichment, a new technology of heat screen at the end of the rotary kiln is developed and applied to reduce the ring formation for the first time. The engineering application of hematite grate and rotary kiln pellets shows that the technological process is intensive, the accumulated time of logistics transportation is 6.04 min, the solid waste resources can be reduced and secondary utilization is realized, and the optimization of thermal engineering system shows that, The energy consumption of the process was reduced from 37.03 kg / t in 2013 to 32.86 kg / t, the consumption of binder was only 10.3 kg / t, the compressive strength was 2707 N / P, and the energy consumption of the process was not much different from that of the energy consumption in the process of the South American belt roaster, but the quality of the oxidized pellets prepared by the grate machine and rotary kiln was better. The effect of the amount of serpentine on the properties of hematite oxide pellets shows that serpentine contributes to the properties of hematite pellets, increases the compressive strength of preheated pellets and roasted pellets, and reduces the reduction expansion rate. The microstructure study of oxidized pellets shows that the solution of MgO and Fe_2O_3 is infinite during roasting and consolidation, which promotes the reaction of solid diffusion, and thus improves the consolidation strength of oxidized pellets. The industrial test of preparing serpentine hematite oxide pellets shows that, The comprehensive cost of pellets was reduced by 35.87 yuan / t, and the compressive strength and metallurgical properties of oxidized pellets were improved. During the process of adding serpentine oxide pellets to blast furnace, the qualified rate of hot metal reached 99.97%, the rate of first-grade products reached 75.06%, and the quality of hot metal was improved. The alkalinity of slag increased from 1.14 to 1.15mg / w\\\%\\\'\\\ {\}\%\\\
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TF046.6

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