Electrons Make Waves

Narrative

What do conventional microwave ovens and the mining industry have in common? On the surface this may seem like a rather bizarre question, but look a bit deeper and the answer is the source of the microwaves themselves.This source is called a magnetron, and the same ubiquitous magnetron technology that heats your food in a microwave oven could also be used to help extract minerals and ore from rock by the mining industry.

The research group, led by Adrian Cross at the University of Strathclyde, are experts in designing and developing high-power microwave sources, such as magnetrons. If the group is successful in its bid to design higher power magnetrons with a commercially viable price-tag, these could then be exploited by the mining industry and radically reduce the amount of energy that is used in the mineral extraction process.

The impact this would have is twofold. First, there is the obvious benefit to the environment, but second, the development and ultimate commercialisation of such technology would create wealth for the UK’s economy.

The current extraction process used by the mining industry involves passing rocks through a crusher to reduce them to a fine dust from which minerals and ore can be removed. However, this simple process comes at a high cost and uses an estimated 4% of the world’s energy resources. This is where high-power magnetrons could make a big difference.

When you put something unsuitable in your microwave, like a china cup, it tends to crack. If you do the same with rock, it also cracks, so that when you come to crush it, it just crumbles. High-power magnetrons would be used to pre-treat rocks with microwaves in order to reduce the amount of energy required to crush them.

Currently magnetrons produced for this application are rated at around 100kW – about 100 times more powerful than a conventional kitchen microwave. If this could be increased to 250kW by the Cross group, the technology would be world-leading and attract substantial interest from mining giants.

Funding provided by the EPSRC, under its Pathways to Impact programme, will help Adrian Cross and his team to reach their goal. The award will be used to initialise a collaboration with e2v Technologies, a UK-based company already manufacturing and selling world-class magnetron technology. “e2v is one of the companies in the UK that can exploit the technology that we are developing,” explains Cross. “We want to provide impact by working with e2v, who have the market to sell these high-power magnetrons worldwide.”

Two members of the Strathclyde group are already working in tandem with e2v, thanks to the EPSRC’s funding. The hope is that the collaboration will pool together the design expertise of the Cross group with the manufacturing capabilities of e2v to produce a truly world-leading high-power magnetron.

“Based on our group’s wealth of experience, we are confident that we can improve on the existing 100kW technology,” says Cross. “It is more a question of designing a magnetron that is commercially viable as there has to be a profit margin for e2v. If we can give them the design for a high-power magnetron, then we are certain e2v can manufacture it and would be able to sell it for years to come.”

Impact status	Open
Category of impact	Economic and commerce, Other