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%.
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