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1、 铁矿石论文：高压辊磨预处理在铁矿氧化球团固结中的作铁矿石论文：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
2、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
3、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
4、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
5、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
6、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 re
7、searched 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 conce
8、ntrate 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 Macrostr
9、ucture 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
10、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 dispers
11、ion 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 p
12、ellet, 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 reactiv
13、ity, 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
14、 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 prom
15、oted 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 inc
16、rease 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 摘要 4-6 ABSTRACT 6-7 第一章 文献综述 10-25 1.1 铁矿氧化球团发展现状及趋势 10-18 1.1.1 铁矿氧化球团在钢铁行业中的地位 10-12 1.1.2 铁矿氧化球团生产现状 12-13
