MgO对碱金属球团还原膨胀性能的影响

Influence of MgO on the reduction swelling performance of alkali pellets

采用压团、焙烧、分步还原(Fe_2O_3→Fe_3O_4,Fe_3O_4→Fe_xO,Fe_xO→Fe)及测定各还原阶段的还原膨胀率的方法来揭示MgO抑制含K、Na碱金属球团还原膨胀的机理。结果表明,随着MgO含量的增加,试样焙烧后磁铁矿或铁酸镁相增加,降低了第一还原阶段的还原膨胀率;含MgO试样焙烧时会生成高熔点渣相,从而抑制第二还原阶段的还原膨胀;MgO的添加抑制了铁晶须的生长,使得第三还原阶段的还原膨胀率降低。

The mechanism of restraining reduction swelling of K and Na containing pellets with MgO was revealed by adop- ting such methods as briquetting, roasting, and step reduction （Fe2O3→Fe3O4,Fe3O4→FexO,FexO→Fe） and measuring the re- duction swelling index of each reduction stage. The results show that, with the increase of MgO content, the roasting of samples leads to increase of magnetite and magnesium ferrite phase,which reduces the swelling index of frrst step reduction ;The roasting of MgO samples will lead to generation of high melting point slag phase, which restrains the second step reduction; The addition of MgO restrains the growth of iron whiskers,which reduces the reduction swelling index of the third step reduction.