Flowsheet considerations for optimal use of high pressure grinding rolls

Abstract High pressure grinding roll (“HPGR”) technology is very rapidly gaining a wide acceptance within the mineral processing industry. Benefits, including a superior energy efficiency and a lower overall operating cost of an HPGR based circuit compared to alternative technologies have been demonstrated at a number of operations throughout the world. Increasing numbers of units are presently being installed in the minerals industry world-wide. This trend is an excellent reflection of the confidence now placed in the technology by new and existing users. This paper summarizes basic principles of the equipment and of various options how to include an HPRG in the grinding circuit for most efficient use. Case studies demonstrate the application of HPGR’s in different grinding circuit set-ups and for the comminution of different ore types. Benefits of the options of open circuit grinding, closed circuit grinding incorporating wet and dry screening as well as the option of achieving a finer grind by recirculating part of the HPGR product using a mechanical splitter are discussed. From a processing point of view the effects of partial product recycle are detailed and some guidance for selection of cut size between HPGR and ball mill is provided.