EVALUATION OF HPGR AND VRM FOR DRY COMMINUTION OF .This is a result of growing challenges associated with the . technologies, such as High Pressure Grinding Rolls (HPGR) and Vertical Roller Mills (VRM), have been successfully used in other industries such as cement and coal for decades, and the literature claims that these . counter rotating rolls, one fixed, and one.back pressure problems in rollers of bowl mills,The Characteristics of Comminution with High Pressure Roller Mills tUniversity ClausthaP. High pressure roller mills have been used successfully for grinding brittle materials . force and energy absorption, the capacity issue and the wear problem. 1. Introduction . for slags, burnt lime, coal, line, diamond ore, silicium ... classifier coarse is sent back to the HP-roller mill, which then is.
back pressure problems in rollers of bowl mills