Köppern Aufbereitungstechnik GmbH & Co. KG (Freiberg, Germany):

Heinicke F., Senior Technologist, PhD in Engineering Sciences, f.heinicke@koeppern.de

Technical University of Bergakademie Freiberg (Freiberg, Germany):

Lieberwirth H., Director of Institute for Mineral Processing
Machines, Doctor of Engineering Sciences, Professor, Holger.Lieberwirth@iam.tufreiberg.de

Kühnel R., Researcher

Saint-Petersburg Mining University (St. Petersburg, Russia):
Aleksandrova Т. N., Head of Chair, Doctor of Engineering Sciences, Professor, Aleksandrova_TN@pers.spmi.ru

It is well known that the use of high-pressure grinding rolls (HPGR) in crushing circuits improves subsequent power consumption through the output of finer material: the yield of fine fractions in the HPGR product is higher than that in the product of traditional crushers (including third and even fourth stage crushing). It has been established that the use of screens in HPGR circuits is inadvisable and would limit the circuit capacity due to lower friction and the fact that screen performance depends on the size of the finished product. In addition, the use of water (its availability and cost) for spiral classifiers, screens, or hydrocyclones remains a major problem in the industry. The alternative option involving air classification has been used in the cement industry for several decades to separate material fractions in the size range of 0.01–1.0 mm, but has yet to find its way to mineral processing plants. It has been shown that volumetric fracturing in HPGR improves subsequent selective separation. Adequate distribution of the ore components in air classifiers allows the separation boundary to be optimized. The expediency of using HPGR in combination with air classification has been substantiated as it allows, in some cases, to eliminate subsequent ball grinding at industrial plants. This is revolutionizing the ore preparation process. The authors are grateful to Köppern for their research support.
The work was carried out with the support of the Russian Foundation for Basic Research (project No. 20-55-12002).

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