还原气氛和脉石成分对氧化球团还原膨胀的影响

以Fe2O3粉为原料,分别配加SiO2,CaO及MgO制备氧化球团,系统研究了H2和CO两种还原气氛及不同脉石成分对氧化球团还原膨胀的影响,并进行了理论分析.研究表明,还原气氛中H2含量的增加,有利于降低球团的还原膨胀率,还原后球团晶体结构完整,品质较好;Fe2O3球团中配加少量CaO,有利于焙烧时产生少量液相而改善球团的冶金性能,但CaO含量不宜过大;在保证产品质量前提下,适当控制球团矿品位,含有少量SiO2等脉石杂质,有利于焙烧时产生渣相连接,提高球团的强度,降低还原膨胀率;球团中添加MgO有利于形成稳定的晶体结构,从而改善球团的性能.

Effects of Reducing Atmosphere and Gangue Composition on Reduction Swelling of Oxidized Pellets

The oxidized pellets were prepared with Fe2O3 and additional SiO2,CaO and MgO separately.The influences of two reducing atmospheres,including H2 and CO and gangue composition on pellets’ reduction swelling were investigated.The results showed that the increasing of H2 in reducing atmosphere is good for lowering the reduction swelling,which ensures the intact grain structure and good quality of pellets.Meanwhile by adding a little CaO in Fe2O3 pellets,some liquid phases are generated in sintering and the metallurgical properties of pellets are improved.However,the amount of CaO should be controlled.Guaranteeing the product quality,slag connection can be obtained in sintering by controlling the TFe of pellets properly and adding some gangue,which lead to the improved strength and reduced reduction swelling.In addition,the properties of the pellets containing some MgO are improved due to the formation of a stable crystal structure.