Investigation the Effect of Grinding Mechanism of Concentrated Fe in Gol-E-Gohar Mine on Quality Indices of Green Pellet

The present study aims to evaluate the effects of fracture mechanism on physical parameters such as size, shape, and specific surface area and to provide a description on how the grinding mechanisms of ball mill and High-Pressure Grinding Roll (HPRG) work. Moreover, the effects of these parameters on qualitative indicators of green pellets were also investigated. Furthermore, the amount of fine particle and surface shape of the obtained particles were compared. Results showed that the specific surface area of particles produced through HPGR is more than Ball Mill. This feature was recognized as the result of the increasing fine particles in the range of 7-25 µm and the presence of micro and macro cracks and fractures on the surface of the most particles manufactured by HPGR. In addition, pelletizing processes of HPGR and ball mill products at the same particle size distribution of 80% less than 43 and 90 µm showed that green pellets produced with HPGR product in d80=90 µm have more drop number and compressive strength in both dry (D.C.S) and wet (W.C.S) modes compared to ball mill. Also, the green pellets produced from HPGR product at d80=43 µm had higher drop number and W.C.S than ball mill product. But, compressive strength of green pellets in HPGR product showed 63.18% lower values of D.C.S than pellets produced by ball mill product at d80=43 µm. The reason for the lower D.C.S of the HPGR product is the increase of fine particles and specific surface area that consequently led to high water absorption by the fine particles.