More Efficient Comminution Process with High-Voltage Pulses Developed
It has been estimated that about 7% of the electrical energy generated worldwide is used for comminution processes. In mining, comminution is the use of crushing, grinding, cutting, or vibrating to reduce the particle size of a material to a smaller average particle size.
In most comminution methods, the feed material is just mechanically stressed. Such processes are very inefficient and have efficiency rarely exceeding 1%. However, a less energy consuming and more resource-saving processing of raw materials using high-voltage pulse technology has increasingly been studied in scientific research in recent years.
Specifically, the hybrid technology, that combines the weakening of the material using means of high-voltage pulses, preferably along grain boundaries of the microstructure, with subsequent mechanical comminution appears to have some potential. For example, an energy savings of 46% could be shown in processing copper ore on a laboratory scale.
The selective liberation of metal-bearing minerals frees the quartz sand of undesired ferrous contaminants. Other advantages over the entirely mechanical comminution techniques used previously include a higher recovery of material and an increased concentrate quality. Also, dust emissions often associated with the comminution processes are significantly reduced.
So far, systems for high-voltage comminution have almost entirely been limited to laboratory systems in batch operation. The few systems currently designed for continuous operation with high current pulses have weaknesses due to the stressing of moving components such as conveyor parts.
However, the Conti-E-Impulse Comminution method presented allows for the continuous use of the technology on an industrial scale with a process room and a scalable pulse generator. The process for the first time does not require any mechanical moving parts and is, therefore, suitable for the processing of both, primary and secondary raw materials as well as building materials. The technology was nominated for the Bauma 2019 innovation award.
The system development was carried out by a team of scientists from the TU Bergakademie Freiberg and the TU Dresden and engineers from the medium-sized, family-owned companies Haver Engineering GmbH, GEOS Ingenieurgesellschaft mbH and Thomas Werner Industrielle Elektronik e.Kfm. In addition to opening up worldwide market potential for equipment deliveries from the participating companies, there are opportunities for consulting services and the possibility of spin-offs by participating scientists. Likewise, the use of the technology in a raw material project of a partner is currently being discussed.
“With lower overall costs, raw materials are used more sustainably by Conti-E-Pulse Comminution and the environmental impact of raw material production is reduced. Thus, even smaller or more complex deposits with strategic elements (such as indium, tungsten, germanium) that were previously not economically viable can be developed in an environmentally friendly manner and used sustainably – an important contribution to the long-term security of Europe’s raw material base. In the field of secondary raw materials, slag processing appears to be particularly interesting. Not only can valuable raw materials be recovered, but also waste can be cleared of contaminants and thus sustainably reused as aggregate, instead of occupying valuable landfill space.”