Abstract
The comminution of commodity particles such as ore minerals in mining and metals from recycling of slags, armoured concrete, and incinerator slags by crushing, grinding, and milling makes up the biggest single cost factor in mineral processing. In spite of a marked lack in the development of new and significantly more efficient comminution equipment, an engineering start-up, PMS Hamburg, has invented and produced an innovative high- velocity impact crusher, the VeRo Liberator®, featuring highly improved particle size reduction ratios and very high degrees of particle liberation together with low levels of energy consumption and operational noise and operates dry, i.e. without using any water.
The VeRo Liberator® is currently designed for a throughput of approximately 100 t per hour and has been tested on a number of different typical bulk ore and slag samples from mines and smelters around the world. Massive sulphide ore from the classic Rio Tinto Mine of the Iberian Pyrite Belt in Spain has been test-comminuted by the VeRo Liberator®. The ore and rare gangue minerals have been reduced in size by an amazing reduction ratio of 480 and have been liberated to a very high degree.
According to our current understanding, these results are due to the unique working principle of the VeRo Liberator®, which is based on high-frequency, high-velocity and therefore high-kinetic-energy impacts inflicted on the material by hammer tools. The hammer tools are mounted on three separate levels of a vertical axle-in-axle system and rotate at variably high speeds clockwise and counter-clockwise against each other. The material and particle stream within the machine is thus highly turbulent and each particle is certainly hammered with high impact forces several times at a high frequency. These high- frequency and high-velocity impacts occur apparently so fast, that stress builds up along the particle boundaries due to differential mechanical behaviour of the inhomogeneous materials. The high frequency of the impacts prevents the various minerals from relaxing sufficiently so that the stress between the different particles is not released quickly enough. Eventually this results in fracture formation along particle boundaries. This new comminution concept offered by the VeRo Liberator® allows the significantly more efficient comminution of ores and recycling materials at far lower energy costs and with far higher
degrees of particle liberation. Due to its enormous reduction ratio the VeRo Liberator® can also replace two to three traditional crushing and milling stages, saving substantially both in CAPEX and OPEX.
Parts of the following text has been presented at various conferences, in conference proceedings volumes and various aspects of the comminution results and on the working principle have been published by Borg et al. (2015 a, b, c).
1 PMS, Abteistrasse 1, Hamburg, Germany
² Economic Geology and Petrology Research Unit, Martin Luther University Halle- Wittenberg, Germany
This paper was presented at the International Comminution and Classification Congress 2015 (ICCC 2015) held in San Luis Potosi, Mexico from 11th to 15th August 2015. Please contact the authors for a full copy of the paper.
Prof. Dr. Gregor Borg
Economic Geology and Petrology Research Unit
Institute for Geosciences and Geography
Commissioner of the University Senate for Foreigners
Martin Luther University Halle-Wittenberg
Von-Seckendorff-Platz 3, D-06120 Halle, Germany
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