【作者】 刘曙光；

【导师】 吕庆；

【作者基本信息】 河北理工大学 ， 钢铁冶金， 2006， 硕士

【摘要】 针对冀东磁铁精矿粉的特点,研究分析了水分、膨润土含量和铁精粉粒度组成对球团成球性能的影响;球团的氧化固结机理和影响焙烧质量的主要因素,提出了改善冀东磁铁精矿粉造球和焙烧的措施。矿相分析表明:冀东磁铁精矿粉以磁铁矿为主,矿粉颗粒为中粗粒变晶结构,多为半自形或他形,呈尖棱碎粒状,其表面光洁平滑,少数有包裹体或连生体,粒径一般为0.05～0.16mm,矿粒存在不完全解理。脉石矿物以石英为主,石英约占4%～6%,同时伴有少量黄铁矿、碳酸盐和硅酸盐等。造球试验研究结果表明:由于冀东磁铁精矿粉颗粒表面光滑,而玻璃质结晶表面的吸水能力和粘结力低于粗糙表面,所以颗粒间摩擦力小;又因脉石含量高,而脉石对铁矿物的亲水性有很大影响,石英被水的润湿性差,降低了冀东磁铁精矿粉的亲水性,导致成球性较差,导致生产中膨润土的配比高于其它优质精矿粉。膨润土配比提高,不仅可以提高生球的落下强度和抗压强度,而且可以明显提高生球的爆裂温度;水分对生球性能影响显著,最佳的造球水分范围为7.9%～8.4%;矿粉粒度的变细,生球强度提高,爆裂温度明显下降。球团焙烧氧化机理的研究结果表明:冀东磁铁精矿球团氧化过程宏观上服从“未反应核模型”;微观上,由于冀东磁铁精矿颗粒存在不完全解理,且磁铁矿晶粒上存在八面体裂解,导致氧化沿八面体裂解或解理缝发展,形成条状或菱形格氧化结构。氧化温度对球团氧化有直接的影响,氧化温度以900～950℃为宜。脉石成分对球团氧化过程没有影响,但是对高温焙烧影响明显。由于冀东磁铁矿粒度粗、SiO2含量高,其焙烧温度不宜过高,冀东磁铁精矿球团最佳焙烧温度以1250～1275℃之间为宜。更多还原

【Abstract】 Considering the characteristics of the Jidong magnetite concentrates. It is researched and analyzed that the influence of moisture, contents of bentonite and granularity composition of fine ore powders on the balling capability; the oxidized and roasted mechanism of Jidong magnetite pellets and the main factors related to the roasting quality. Brought forward the measures to improve the balling and roasting of Jidong magnetite fine.By mineralogical analysis of Jidong magnetite concentrates what can be found is that: It is mainly composed of magnetite, concentrate grain is medium-coarse granular crystal texture, the most is subidiomorphic or xenomorphic, is chevron and granulated, surface of the concentrate is smooth, minority of concentrate has inclusion or intergrowth, grain inch normally is 0.05~0.16mm, there is incompletely cleavage in concentrate grain. Gangue minerals mostly is quartz, the ratio of quartz is 4%~6%, also there are few pyrite、carbonate and silicate ect.By balling experiment what can be found is that: because glazed surface of Jidong fine magnetite concentrate, moreover water intake capacity and adhesion of glassiness crystal surface is worse than that of coarse surface, so friction between grains is small; as well as owing to high gangue content, and that gangue has big impact on hydrophile of iron ore, low wettability of quartz, so hydrophile of Jidong fine magnetite concentrate is reduced, result in balling capacity is bad. Therefore at production, bentonite proportion in Jidong magnetite concentrates more that in other high quality concentrate. With bentonite ratio increasing, not only can improves green ball drop number and compression strength, but also can increases green ball shock temperature; moisture has markedly effect on green ball properties, optimal balling moisture should be 7.9%~8.4%; With reduction of concentrate inch, green ball strength increases, but shock temperature decreases markedly.By roasting oxidation experiment what can be found is that: The oxidation process of Jidong magnetite concentrate pellets obeys“unreacted core model”macroscopically, but in microscopic, there is incompletely cleavage in Jidong magnetite concentrate grain, and octahedron crack exists in magnetite crystal, oxidation develops along octahedron crack or cleavage seam, forms strip oxidation texture or diamond lattice oxidation texture. Oxidized temperature has directly effect on balling oxidation, the oxidizing temperature is reasonable between 900℃to 950℃. Gangue composition has no impact on pellets’oxidation process, but has markedly impact on roasting. The optimal roasting temperature of Jidong magnetite concentrate pellets is between 1250℃to 1275℃.更多还原