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%.