High Pressure Grinding Rolls (HPGRs)have 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 circulation loops, to final grinding of <0.4mm material to high Blaine values in the preparation of pellet feed.
HPGR grinding significantly enhances over all through put. This results in the creation of a large proportion of finished product and the reduced Bond Work Index of the pressed material. This generally allows for a reduction in the projected number of equipment units in tertiary crushing, quaternary crushing and grinding.
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.
This particle bed is created between two choke-fed, counter-rotating rolls. Between these rolls, a particle bed is pressed to a density of up to roughly 85%of the actual material density. This compression is achieved by applying high pressure of up to nearly 300Mpa, exceeding the compression strength of the feed material. During this compacting process the material is ground to a wide particle size distribution with a large proportion of fines, compacted into flakes.
HPGR grinding significantly enhances over all through put. This results in the creation of a large proportion of finished product and the reduced Bond Work Index of the pressed material. This generally allows for a reduction in the projected number of equipment units in tertiary crushing, quaternary crushing and grinding.
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.
This particle bed is created between two choke-fed, counter-rotating rolls. Between these rolls, a particle bed is pressed to a density of up to roughly 85%of the actual material density. This compression is achieved by applying high pressure of up to nearly 300Mpa, exceeding the compression strength of the feed material. During this compacting process the material is ground to a wide particle size distribution with a large proportion of fines, compacted into flakes.