铁矿石论文：高压辊磨预处理在铁矿氧化球团固结中的作用
【中文摘要】高压辊磨预处理具有明显改善铁矿氧化球团质量和降低生产能耗等作用,在铁矿氧化球团生产中已经开始得到推广应用。关于高压辊磨在铁矿氧化球团生产中的作用研究较多的是对生球质量改善方面,对其在铁矿氧化球团固结中的作用及机理研究较少,认识尚不深入。研究高压辊磨在铁矿氧化球团固结中的作用对加快其在铁矿氧化球团生产中的应用具有重大意义,有助于我国钢铁生产行业技术进步。本文分别以袁家村赤铁精矿和峨口磁铁精矿为研究对象,在研究高压辊磨对铁矿氧化球团固结强度的影响基础上,运用X射线衍射分析、激光粒度分析、光学显微结构分析等现代技术手段,从高压辊磨后铁精矿的比表面积、晶格缺陷程度、微细颗粒含量,以及分散程度与铁精矿球团固结强度的关系等方面,并结合高压辊磨对铁精矿球团氧化动力学、宏观或微观结构的影响,系统地研究了高压辊磨预处理在铁精矿氧化球团固结中的作用机理,取得以下结论：(1)高压辊磨预处理具有显著提高赤铁矿氧化球团固结强度的作用,能明显降低预热焙烧温度和缩短预热焙烧时间,但是对磁铁矿氧化球团的固结强度没有明显的提高作用。(2)高压辊磨后铁精矿性能与铁矿氧化球团固结强度的关系研究发现,高压辊磨预处理后,原料分散程度差及微细颗粒含量增大是影响铁矿氧化球团固结强度的主要原因。(3)赤铁精矿在高压辊磨机对辊的高压下形成坚硬的料饼,大量坚硬的颗粒聚合体保留到铁矿球团中,提高了铁矿球团颗粒接触面积；同时,赤铁
精矿中微细颗粒,特别是-0.005mm粒级含量的增大,提高了铁矿球团的紧密程度和矿物颗粒的表面活性,促进了固相结晶反应,有利于Fe203微晶键的形成及高温再结晶过程,从而提高了预热焙烧球团冷态强度。(4)磁铁矿球团氧化动力学研究结果表明,在850℃-1000℃温度范围内,磁铁矿球团氧化反应过程受内扩散控制,高压辊磨不能改变氧化过程的控制环节,仅能使磁铁矿球团氧化反应的表观活化能提高10.58 kJ/mol。高压辊磨后铁精矿分散程度差和微细颗粒含量的增大,一方面促进了固相结晶反应,另一方面也加快了磁铁矿球团表面颗粒的氧化反应和致密氧化层的形成,阻碍了氧气的扩散,从而降低了磁铁矿球团的氧化程度,导致焙烧球团致密壳层的形成和内应力的提高,不利于磁铁矿氧化球团冷态强度的提高。
【英文摘要】The quality of iron ore oxide pellet is developed and the consuming energy in production is reduced obviously by using High Pressure Roll Grinding (HPRG) which has been applied widely in iron ore oxide pellet production. Majority of the research in function of HPRG in iron ore oxide pellet are related to the improvement of green ball quality, but less to the function of HPRG in consolidation of iron ore oxide pellet with few points. Study of the function of HPRG in consolidation of iron ore oxide pellet has profound
significance for the application of HPRG in the production of iron ore oxide pellet and promotes the progress of production
of iron and steel industry.The function and mechanism of HPRG as material-pretreating technology in the consolidation of iron ore oxide pellet were researched systematically in this dissertation, using Yuanjiacun hematite concentrate and Ekou magnetite concentrate as raw materials and the modern analytic technologies of X-ray diffractometry, laser-size, Optical Microstructure, etc, in terms of the relationship of characteristics of iron ore concentrate after being pretreated by HPRG, such as the specific surface area, lattice distortion extent, particle-size distribution, the content of fine particles, the dispersion extent and the consolidation characteristics of preheated and roasted pellets, as well as the effects of HPRG on the Macrostructure and Microstructure of preheated and roasted pellets, Oxidation dynamics of magnetite pellet, with the results as following:(1) The research results revealed that the compression of hematite preheated and roasted pellets was obviously developed by HPRG, but not for the magnetite preheated and roasted pellet.(2) The study of the relationship between the characteristics of iron ore concentrate after being pretreated by HPRG and the consolidation characteristics of iron ore oxide pellet revealed that when raw materials of hematite and magnetite were
pretreating respectively, the bad dispersion of pretreated materials and the increase of fine particles were the main reasons that affect the compression of iron ore oxide pellet.(3) The iron ore concentrate was compacted hardly under high pressure roller and consequently massive compact
particle-particle unites were remained in iron ore pellet, which promoted the increase of particle-particle contact areas; meanwhile the development of size distribution and increase of fine particles content, especially for the-0.005mm both contributed to the compact extent of iron ore pellet and surface-activation, promoting the solid phase reactivity, all of which contributed to the formation, growth and contact of fine Fe2O3, as well as to the crystallization process of Fe2O3 under high temperature, promoting the increase of
compression.(4) The result of oxidation dynamics of magnetite pellet revealed that the oxidation process of magnetite pellet was controlled by the oxygen diffusion in pellet and it was not changed by HPRG, but the apparent activation energy of magnetite oxidation increased 10.58 kJ/mol between 850℃-1000℃. The increase of compaction of magnetite pellet and the bad dispersion of pretreated materials both not only promoted the solid phase reactivity, but also promoted the oxidation
rate of magnetite and the formation of compact layer on the magnetite pellet surface, restricting the diffusion of oxygen. Therefore the oxidation extent of magnetite pellet was lowered, promoting the double layer formation and the increase of internal stresses of magnetite roasted pellet, which limited the compression increase of magnetite oxidized pellet.
【关键词】铁矿石 铁矿球团 高压辊磨 球团孔隙率 氧化动力学 【英文关键词】iron ore iron ore pellet high pressure roll grinding pellet porosity oxidation dynamics
【目录】高压辊磨预处理在铁矿氧化球团固结中的作用4-6
ABSTRACT6-7
第一章 文献综述10-25
摘要1.1
铁矿氧化球团发展现状及趋势10-18钢铁行业中的地位12-13
10-12
1.1.1 铁矿氧化球团在
1.1.2 铁矿氧化球团生产现状
1.2 原料高压
1.1.3 铁矿球团发展趋势13-18
辊磨预处理在铁矿氧化球团生产中的研究及应用现状18-24
1.2.1 高压辊磨机工作原理
18-19
1.2.2 高压
辊磨参数的影响19-22响研究22-23能的影响研究23中的应用现状23-24
1.2.3 高压辊磨对铁矿生球质量的影
1.2.4 原料高压辊磨预处理对铁矿球团固结性1.2.5 原料高压辊磨预处理在铁矿球团生产1.3 本研究的目的和意义24-25
2.1 原料性能
第二章 原料性能及研究方法25-32
25-2625-26理方法2626-27
2.1.1 铁精矿252.2 研究方法26-32
2.1.2 膨润土
2.2.1 原料高压辊磨预处
2.2.2 铁矿球团预热焙烧试验方法
2.2.3 高压辊磨后原料性能与铁矿氧化球团固结强度
2.2.4 铁矿氧化球团结构构造研究方
第
的关系研究方法27-30法30
2.2.5 磁铁矿球团氧化动力学研究方法30-32
三章 高压辊磨预处理在赤铁矿氧化球团固结中的作用32-46响32-3333-35
3.1 高压辊磨对赤铁矿预热焙烧球团强抗压强度的影3.2 高压辊磨对赤铁矿球团预热焙烧制度的影响3.2.1 赤铁矿球团预热制度
33-34
3.2.2 赤铁
矿球团焙烧制度34-353.3 高压辊磨后原料性能与赤铁矿氧
3.3.1 比表面积
3.3.3 分散程度
3.4 高压辊磨对赤3.5 本章小结
化球团固结强度的关系35-4335-3738-41
3.3.2 晶格缺陷37-383.3.4 微细颗粒含量41-43
铁矿预热焙烧球团微观结构的影响43-4545-46用46-63响46-4747-49
第四章 高压辊磨预处理在磁铁矿氧化球团固结中的作4.1 高压辊磨对磁铁矿预热焙烧球团抗压强度的影4.2 高压辊磨对磁铁矿球团预热焙烧制度影响4.2.1 磁铁矿球团预热制度
47-48
4.2.2 磁铁
矿球团焙烧制度48-494.3 高压辊磨后磁铁精矿性能与磁铁
4.3.1 比表面积4.3.3 分散程度
矿氧化球团固结强度的关系49-5349-50
4.3.2 晶格缺陷50-51
51-524.3.4 微细颗粒含量52-534.4 高压辊磨对磁
铁矿球团氧化动力学的影响53-60力学模型54-5555-5858-6060-61
4.4.1 磁铁矿球团氧化动
4.4.2 未预处理磁铁精矿球团等温氧化试验
4.4.3 高压辊磨预处理后磁铁精矿球团等温氧化试验4.5 高压辊磨对磁铁矿预热焙烧球团宏观结构的影响4.6 本章小结61-63
致谢69-70
第五章 结论63-攻读硕士学位期间主要研
参考文献-69究成果70
