BaSO4对球团矿抗压强度的影响

以磁铁精矿粉和膨润土为原料、BaSO4为添加剂生产球团，基于直接配入法的组分调控方式，结合热重实验结果，研究了BaSO4对球团矿抗压强度的影响，并采用压汞仪、矿相显微镜和扫描电子显微镜?能谱仪等分析了球团矿焙烧过程中BaSO4对球团矿抗压强度的影响机理和钡的转变行为。结果表明，随BaSO4含量增加，预热球团抗压强度变化较小，焙烧球团抗压强度先升高后逐渐降低。BaSO4添加量小于1.5wt%时，有利于焙烧球团内部磁铁矿氧化和新生赤铁矿再结晶，孔隙率略有增加，内部氧分压提高，增强了晶粒间的固结程度，球团抗压强度提高。BaSO4含量进一步增加，球团矿内部孔隙尺寸增大，降低了内部基体的整体性，使晶粒间的连晶程度减弱，球团矿抗压强度降低。

Effect of BaSO4 on the compressive strength of pellets

The magnetite concentrate powder and bentonite which were obtained from a domestic iron and steel enterprise were used as raw material to produce pellets. The chemical composition of pellets was adjusted by adding different proportions of raw materials, and the effect of BaSO4 on compressive strength of pellets was studied on the basis of the thermogravimetric experiment results in this paper. The influence mechanism of BaSO4 on compressive strength of pellets and the transformation behavior of barium in pellets were analyzed mostly by using the mercury porosimetry, mineral phase microscope and scanning electron microscope?energy dispersive spectroscopy (SEM?EDS). The results showed that the compressive strength of preheated pellets changed little and the compressive strength of roasted pellets increased firstly and then decreased gradually with the mass fraction of BaSO4 increasing. As far as the roasted pellets were concerned, the porosity increased slightly and interior oxygen partial pressure was also increased when BaSO4 content was less than 1.5wt%, which contribute to the oxidation of magnetite and recrystallization of regenerated hematite in pellets. In addition, the degree of bonding between grains was strengthened. Owing to the above-mentioned reasons, the compressive strength of pellets increased. However, when the mass fraction of BaSO4 was further increased, the large size pores were produced, which destroys the integrity of the matrix inside the pellets and decreased the degree of crystalline between the grains. Therefore, the compressive strength of pellets was reduced when the content of BaSO4 was more than 1.5wt%.