含铁添加剂代替膨润土对球团矿性能的影响  

Effect of Iron-Containing Additive as Substitute for Bentonite on Pellet Properties

作　　者：任杰 罗果萍[1] 朱建国[1] 宋巍[1] 柴轶凡[1] REN Jie;LUO Guo-ping;ZHU Jian-guo;SONG Wei;CHAI Yi-fan(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014000,Inner Mongolia,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014000

出　　处：《矿冶工程》2022年第4期106-111,共6页Mining and Metallurgical Engineering

基　　金：国家自然科学基金(51364030)。

摘　　要：以某钢厂使用的2种磁铁精粉为原料,分别配加一定比例优等成球性的含铁添加剂代替膨润土,探究含铁添加剂对生球性能、预热球强度及焙烧球强度、还原性和还原膨胀性的影响。结果表明,随着含铁添加剂配比增加,生球抗压和落下强度明显提高,爆裂温度逐渐下降,该添加剂适宜配比为6%~8%,在此区间内,生球落下强度大于4次/(0.5 m),抗压强度大于10 N/个,生球爆裂温度大于600℃,焙烧球强度大于2 000 N/个,均满足生产要求。显微观察发现,随着含铁添加剂配比增加,球团显微结构中大片FeO晶体区域逐渐变小,焙烧球晶桥连接受阻、晶粒互连程度降低、连晶面积减小,晶体间均匀细小的孔隙逐渐聚集、变大。添加剂配比从4%增加到10%,焙烧球强度从2 425.5 N/个降到1 890.6 N/个,球团矿还原度从71.46%提高到76.04%,还原膨胀率由11.3%降低到8.1%。Factsage7.1热力学计算结果表明,添加剂配比增加会使球团矿液相生成温度提高,液相生成量减少,当焙烧温度低于1 300℃时,液相生成量在生产允许范围之内(约低于5%)。Two kinds of magnetite concentrate from a steel plant were taken as raw materials in an experiment on pelletization, and a kind of iron-containing additive, good for pelletizing, was added to replace bentonite respectively according to a certain proportion for exploring the effect of this additive on the properties of green pellets, including the strength of preheated pellets, the strength, reducibility and reduction swellability of the roasted pellets. It is found that increasing the proportion of this iron-containing additive can obviously improve the compressive strength and drop strength of green pellets, but gradually decreases their cracking temperature. The appropriate amount of the additive is decided to be 6%-8%. Within this range, the drop number and the compressive strength of green pellets is more than 4 times/(0.5 m) and more than 10 N per pellet, respectively, the cracking temperature is more than 600 ℃, and the strength of roasted pellets is more than 2 000 N per pellet, indicating all meeting the production requirements. Microscopic observation shows that by increasing the amount of iron-containing additive, the larger area of FeOcrystal in the microstructure of pellets becomes smaller, the connection among the crystals in the roasted pellets is hindered, the interconnection degree of crystal grain is reduced, the area of intergrown crystals decreases, and the uniform and fine pores between crystals gradually conglomerate and become larger. With the adding amount of additive increased from 4% to 10%, the strength of roasted pellets decreases from 2 425.5 N per pellet to 1 890.6 N per pellet, the reduction degree of pellets increases from 71.46% to 76.04%, and the reduction swellability rate decreases from 11.3% to 8.1%. The thermodynamic calculation with Factsage 7.1 shows that increasing the amount of the additive can raise the generation temperature of liquid phase of pellets, leading to a reduction of generated liquid phase. With the roasting temperature lower than 1 300 ℃, the generated li

关 键 词：球团 含铁添加剂 抗压强度 还原性能 磁铁矿 烧结球团 

分 类 号：TF046[冶金工程—冶金物理化学]