Scots researchers believe they’ve mapped a way to recover rare metals vital to rebuild and replace ageing wind turbines. Stereotypically enough, whisky plays a part in their success.
New process research funded by the Industrial Biotechnology Innovation Centre (IBioIC), Aberdeenshire-based “circular economy” innovators SEM and Edinburgh University’s researchers, has unearthed a route to extracting highly valuable elements from waste alloys.
Rare metals such as niobium, tantalum and rhenium are critical to strengthening steel, adding stability & endurance to high-impact structures including turbine towers. But such resources are mined outside the UK, often using methods harmful to the environment.
Manufacturers know that, by recovering rare metals at the end of a structure’s lifecycle – including from many of Scotland’s older wind turbines – they could re-use them in making new alloys, and cutting down Britain’s exposure to imports.
No suitable extraction plant currently exists in the UK, sadly, though. Fabricators, including of turbines, must send end-of-life waste to be processed in Canada, home to the world’s only rejuvenation facilities.
Using waste compounds supplied by Advanced Alloy Services, a Sheffield-based maker of specialist metals for the aerospace & energy sectors, the researchers reckon they’ve hit on a solution.
The trick is to begin by treating the elderly compounds with a combination of bio-based chemicals, some derived from whisky distilling, to separate the alloys’ components.
Using chemicals by-produced on the way to making Scotland’s “water of life”, SEM’s pioneering DRAM system acts as a filter to ensure the resultant waste liquids are safe to dispose of. The DRAM technology was developed to safely extract valuable metals from waste electronics.
SEM’s lead metallurgist Leigh Cassidy said: “These rare metals are essential for the integrity of steel-based components commonly used in wind turbines and other high-temperature engines, but most of the stocks are still mined from the earth.
At the same time, we have ageing infrastructure coming to the end of its life. Substantial amounts of the components could be re-used”.
One DRAM thing after another
Cassidy went on; “We’ve already worked with the University of Edinburgh on methods for safely extracting metals from waste electronics. We saw an opportunity to explore a similar technique for separating the different metals in alloys.
“If used at scale, this type of process could be a big boost for UK manufacturing and unlock a new sustainable, circular supply chain where rare metals are recovered from existing alloys.
“Only small quantities of these rare metals are obtained as a result of the destructive mining processes, but with a process like this adopted at scale, there should be no need to cause additional harm to the planet”, the SEM metallurgist added.
“The project has contributed to the company’s mission of turning waste into value by focusing on resource recovery. We’re excited to continue exploring ways to collaborate with others and further advance solutions that showcase the art of the possible for industries looking to build upon sustainable processes.”
Dr Liz Fletcher, director of business engagement at IBioIC, added: “SEM is a great example of a business taking a bio-based process and applying it to multiple sectors to help companies achieve environmental goals.
“By joining forces with academic experts, SEM has developed potentially game-changing processes for sustainably treating various types of waste. Recycling at an industrial scale will be key to achieving net zero, while also reducing the carbon footprint and environmental damage associated with imported raw materials.”