Effect of the Recycling Load on the High Pressure Grinding Rolls' Performance - A Case Study with the Industrial Unit During Cement Clinker Grinding

DÜNDAR H., AYDOĞAN N., Benzer H., Lynch A. J.

10th Mill Operators Conference, Adelaide, Australia, 12 - 14 October 2009, pp.161-163 identifier

  • Publication Type: Conference Paper / Full Text
  • City: Adelaide
  • Country: Australia
  • Page Numbers: pp.161-163
  • Hacettepe University Affiliated: Yes


It is well known that the high pressure grinding rolls (HPGR) can only be operated efficiently under choke feeding conditions in which a material bed is built up between the rollers to ensure interparticle breakage. By increasing the fines amount in the material bed up to a specific level with the recycling load, a uniform material bed is created and higher pressure gradient along the roller width is obtained which results in compact flakes including more fines. Extensive test work has been carried out with an industrial HPGR unit grinding cement clinker in a cement plant in Turkey. During the test work the recycling load of the circuit was changed to achieve different ratios to the fresh feed rate in order to identify the effect of the recycling load on the circuit performance. Six different tests were performed with the circuit at steady state. For each test, samples were collected from HPGR fresh feed and discharge, and total feed, then the particle size distributions of the samples were determined and mass balances around the circuit were calculated. The conclusion was that the reduction ratio of the HPGR increased with increase in recycling load. The flake densities showed the same trend with more compacted flakes being produced for higher recycling loads.