Effect of BaSO₄ on the compressive strength and reduction behavior of pellets

To provide theoretical basis for the production of pellets, the effect of BaSO₄ in the range of 0 to 5.0% on properties of pellets was studied under experimental conditions. The influence mechanism of BaSO₄ on the compressive strength of preheated pellets as well as roasted pellets and reduction behavior of roasted pellets was investigated by means of scanning electron microscopy-energy dispersive spectrometer (SEM-EDS). From the results, it can be observed that the compressive strength of preheated pellets varies slightly whereas roasted pellets has a great change when BaSO₄ content increases from 0 to 5%. The compressive strength of roasted pellets initially increases then decreases, which reaches the peak value of 3411 N with BaSO₄ content of 1.5%. The reduction degree enhances from 80.7 to 97.9% and FeO content reduces from 2.33 to 1.57% with increasing BaSO₄ content from 0 to 5.0%. The degree of polycrystalline of hematite improves and the hole size increases obviously when BaSO₄ content varies from 0 to 1.5%. The crystallization of hematite decreases and the holes whose distribution is uneven increases when BaSO₄ content is more than 1.5%. In reduction process, the wustite reduces and metallic iron increases with increasing BaSO₄ content from 0 to 5.0%.