Friday, 16 July 2010

Confidence in HPGR technology continues to grow

High pressure grinding rolls (HPGR) have been much in the news lately (see posting of 18th May).

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.

A paper by van der Meer and Gruenden of HPGR manufacturer KHD Humboldt Wedag, Germany (Minerals Engineering Volume 23 issue 9, 2010) summarizes the basic principles of the equipment and of various options of how to include an HPRG in the grinding circuit for most efficient use. Case studies demonstrate the application of HPGRs 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.

7 comments:

  1. There are a schools of thoughts - none established though - HPGR breaks the Crystalline structure and thus the Grinding energy requirement downstream decreases. How far is this true? My personal feeling is thet the BWi does not change if you SAG and Ball vs HPGR and Ball.

    Debjit Mukherjee, Bateman, India

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  2. Hello, I have just read the article above. There does not seem to be many manufacturers of HPGR at present. Would you know if a HPGR must use electric motors to power the rolls or could a diesel or gas engine work ?

    Jean-Yves TILLIER, Thermofluids CAE, UK

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  3. Diesel or gas generators certainly will work to power a HPGR dual drive electric motor.
    Even hydraulic drives would work. HPGR can be either variable speed or fixed Speed, depentent on application.

    Edward Wipf, Weir Minerals, Canada

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  4. Controlled piston-die tests indicate that closed-circuit conventional crushers (designed for interparticle crushing under choke-feed conditions), should have about the same energy energy efficieny (based on net power) as a single-pass HPGR at fine sizes. In other words, for a given specific energy, the size distributions at fine sizes (down to 38 microns) are very similar. However, closed circuit cone crushing should be more energy efficient than a single-pass HPGR crushing at the 80 to 95 per cent product passing sizes.

    The no-load power of HPGR's seem to be attractively low (less than about 7 per cent) compared with conventional crushers (possibly up to 50 per cent). I would welcome comments from crusher suppliers on the minimum no-load powers one can expect for both conventional cone crushers and HPGR's.

    Adrian Hinde, Mintek, South Africa

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  5. Cristian Garrido22 July 2010 at 16:13

    Last year I attended the course "Application of HPGR's to the mineral industry" of PROCEMIN2009 (http://www.procemin.cl/cierre2009/) and there was little application to the copper industry. Has changed this situation?

    El año pasado asistí al curso "Application of HPGR's to the mineral industry" del PROCEMIN2009 (http://www.procemin.cl/cierre2009/) y era escasa la aplicacion a la industria del cobre. Ha cambiado esta situacion?

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  6. Conventional cone crushers work well but wear life reduces highly with hard abrasive material. Further, cone crushing may not be recommended for crushing down anything below 6 mm. With abrasive material (Abrasiveness > 1500 g/t) the liner life might not exceed 500 hrs for such crushing application.
    How shall HPGR contribute to crushing hard abrasive material down to 6 mm. Can a product as coarse as 6 mm be produced....what is the recomended top size in feed?
    Debjit Mukherjee, Bateman India

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  7. Could anyone give me the number of HPGR units installed in 2012 or 2013 across the globe. Alternately, kindly suggest average number of units installed each year.

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