共查询到18条相似文献,搜索用时 125 毫秒
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西方研究了几种铁精球团矿在煤基回转窑直接还原过程中热态强度变化规律。结果表明:添加“复合粘结剂”铁精矿冷固球团矿在还原过程中抗压强度下降幅度和强度低谷区宽度上于预热球团矿,水泥冷固球团矿和氧化才矿,其热态强度能满足工业生产加转窑的要求,适于做回转窑直接还原炉料。 相似文献
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本文详细地研究了铁精矿冷固球团在煤基回转窑内的还原机理。研究结果表明:“复合粘结剂”集粘结、催化和还原功能于一体,能使冷固球团矿按均质反应模型还原。因此冷固球团矿具有良好还原性和足够的机械强度,消除了低温还原粉化,是一种直接还原的新炉料。 相似文献
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本文研究了提高铁精矿冷固结球团矿强度的有效途径,结果表明,在适宜的铁精矿细度,混合料预处理方式与时间下,添加新型粘结剂NB-1,比“复合粘结剂”CB的抗压强度指标提高45%以上,而膨润土不适于制备冷固球团。 相似文献
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摘要:添加有机粘结剂代替部分膨润土是减少成品球团矿的脉石含量的有效途径之一。通过残烧实验和XRD研究了膨润土与有机粘结剂间的相互作用,结果表明有机复合粘结剂比原始膨润土的晶层间距增加了008 nm。造球和焙烧实验结果表明,添加有机粘结剂替代膨润土可以提高生球落下和抗压强度。气基还原实验结果表明,添加有机粘结剂替代05%(质量分数)膨润土可以提高球团矿还原性,还原粘接指数也同时升高。SEM显微结果表明,添加有机复合粘结剂可以提高球团矿的孔隙率,有利于还原气体进入球团矿内部,从而改善球团矿的还原性。为制备有机复合粘结剂球团矿提供了参考,有助于扩大有机复合粘结剂在炼铁中的应用。 相似文献
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实验室研究表明,采用GR型复合粘结剂制成的冷固球团,固结速度快,在短时内可获较高强度;具有良好的抗爆裂性、还原性和耐还原粉化性。GR型复合粘结剂价格低廉、不含P、S,来源广泛,是冶金工业中含铁粉料常温造块的优质粘结剂。 相似文献
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《钢铁冶炼》2013,40(6):421-425
AbstractThere is a need for the development of efficient industrial processes to use iron ore fines of high grade. Attention is particularly drawn to rotary kiln sponge ironmaking technology using lump iron ore, where productivity is low and energy consumption high compared with gas based processes. Fundamental studies carried out elsewhere indicate that the reduction of lump iron is accelerated if a limited amount of carbonaceous material is incorporated in the agglomerate of iron ore fines. Based on these considerations, cold bonded ore–coal composite pellets have been developed for sponge ironmaking in a rotary kiln. These composite pellets were tested in the laboratory and found to reduce very quickly, compared with lump iron ore. Composite pellets were also tested in an 8 t/day rotary kiln sponge iron plant giving enhanced productivity and lower coal consumption, and these results will be presented in Part 2 of this paper (next issue). 相似文献
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《钢铁冶炼》2013,40(5):429-432
AbstractA new cold bonding technology for producing coal bearing composite pellet was developed. Laboratory tests showed that the cold bonded pellet has enhanced mechanical strength, from which good quality DRI can be produced. Based on the laboratory test results, a rotary kiln process was designed for producing DRI. Because of the high metallisation rate of the pellets and the corresponding novel operation conditions, the proposed rotary kiln process has significantly higher energy efficiency than the SL/RN process, hence emitting less CO2. 相似文献
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降低膨润土用量是提高球团品位、实现节能减排的有效途径之一。基于新型高效复合粘结剂,通过生球制备、线性拟合分析、生球力学特征分析等手段研究了复合粘结剂对生球质量的影响规律及与重要指标的构效关系,阐明了复合粘结剂提高生球质量的作用机理。结果表明:配比(质量分数)为1.2%膨润土+0.028%有机粘结剂的复合粘结剂球团,落下强度(0.5 m高度落下次数)达到6.2、平均抗压强度达到14.5 N、爆裂温度达到542 ℃,与2.0%膨润土球团相比,生球质量相近,但膨润土消耗减少40%;基于构效关系分析,有机粘结剂对生球落下强度、爆裂温度作用显著,膨润土对干球强度影响更大;有机粘结剂通过增强颗粒的亲水性、毛细力和黏性力强化了生球落下强度,干燥时在表层形成少量孔隙,有利于球团内水分的排出,提高了生球爆裂温度,干燥后以固态连接桥的形式强化干球强度,但是孔隙的位点和尺寸可能会降低干球强度,因此,对干球强度起决定性作用的是膨润土,有机粘结剂对干球强度的影响呈现多面性。 相似文献
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马勇 《金属材料与冶金工程》2003,31(1):21-24
通过煤种,入窑球冷态强度和还原过程强度,以及钛精矿与煤灰混合物的软化温度等分析探讨了钛精矿预热球团回转窑直接还原产生结圈的可能性,获得了可以避免结圈的结论。 相似文献
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回转窑结圈一直以来是制约煤基回转窑直接还原工艺发展的重要因素,以某低品位铁矿回转窑还原结圈物为研究对象,深入研究回转窑结圈物的特性及其形成机制.从结圈物的宏观形貌、物化性能、软熔特性和微观结构入手对某低品位铁矿球团回转窑结圈物的特性进行分析,并结合热力学相图、化学物相及能谱分析研究了结圈物的形成机制.结果表明:结圈物由熔融物包裹球团形成,接近窑壁,其熔融包裹物增多,结圈物中MFe、CaO含量明显增大,软熔温度越低;由球团粉末中FeO与SiO2形成的铁橄榄石及煤灰带入的CaO而形成的钙铁辉石低熔点相是造成结圈的主要原因;低熔点相的存在同时也促进了金属化球团间铁晶粒的相互扩散与迁移,从而加剧了结圈现象. 相似文献
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Large amounts of fines and superfines are generated in Indian iron ore and coal mines due to mechanized mining and mineral dressing operations. Utilization of these fines for extracting metal is of vital concern for resource utilization and pollution control. For agglomeration of these fines, a suitable binder is required. Iron ore-coal composite pellets were prepared by cold bonding. Various binders such as lime, Ca(OH)2, slaked lime, dextrose, molasses, and sodium polyacrylate (SPA), alone or in combination, were employed for making composite briquettes. The slaked lime–dextrose combination produced the highest strength among the various binders employed for producing composite briquettes and was therefore selected for producing composite pellets for the smelting reduction. In cold bonding, the composite pellets attain the requisite properties due to physico-chemical changes of the binder in ambient conditions. It was possible to obtain a dry strength of more than 300 N per pellet in some cases and more than 200 N per pellet in many trials. Drop strength and shatter index values of composite pellets were also measured. In the present paper an attempt has been made to evaluate the mechanical properties of cold-bonded composite pellets so as to throw some light on the capacity of these pellets to withstand stresses during handling and transportation. 相似文献