High Pressure Grinding Rolls (HPGRs) is similar in principle to regular grinding rolls but material is subjected to much higher forces. HPGRs consists of a pair of counter rotating rolls, one fixed and the other floating. Material is fed between the rolls with the floating roll pressing against the material flow by means of hydraulic pressure in excess of 50 MPa. The resulting force causes the material to compact by inter particle breakage. Pressures and roll speeds are adjusted to obtain optimum grinding conditions. The roll faces are typically studded because of improved wear characteristics.
