High Pressure Grinding Rolls (HPGR) were introduced as a new grinding technology in 1984. Since then, they have been successfully installed in a large number of plants throughout the world, mainly for cement and limestone. More recently, HPGRs have also been applied in mineral processing plants, largely in iron ore and diamond treatment. In these industries, the application of HPGR ranges from coarse grinding, e.g. the grinding of 65mm (2.5”) size excess pebbles in AG circulation loops, to final grinding of <100μm material to high Blaine values in the preparation of pellet feed.
High pressure grinding is achieved by an advanced type of grinding roll. Contrary to conventional crushing rolls, the particles are broken by compression in a packed particle bed, and not by direct nipping of the particles between the two rolls.