Grinding iron ore concentrate by using HPGR and ball mills and their effects on pelletizing and reduction stages - a pilot-scale study

Abstract

ABSTRACT An iron ore concentrate sample was ground separately in a pilot-scale HPGR mill in multiple passes and a dry open-circuit ball mill to increase the specific surface area of particles. The effects of grinding mechanisms on generating pellet feed were assessed and pellets and DRIs were produced. Drop number, green and dry compression strengths of green pellets produced by HPGR samples were improved. For fired pellets, CCS was more than 2793 N/P, FeO content was lower than 1%, and porosity of HPGR samples decreased by 2.7%. In Linder tests, the reduction degree of DRIs produced by HPGR samples decreased by 4%. All DRIs have equal metallization degree and reduction disintegration index. Total and metallic Fe values obtained through ball mill samples increased by 1%−2%, and CCS of DRIs was within the 598–715 N/P range. As a result, applying ball mill grinding compared to HPGR produces DRIs with higher quality.