Scientia Professor Veena Sahajwalla is using previously unexplored high temperature reactions to transform some of the world’s most problematic and toxic wastes into commercially viable new ‘green’ materials.
Her successes have led her to be dubbed the ‘modern-day alchemist’ and could lead to a new manufacturing revolution.
The internationally recognised materials scientist and engineer is the director of UNSW’s Centre for Sustainable Materials Research and Technology (SMaRT@UNSW), and also leads an $8.8 million ARC green manufacturing research hub developing new processes to direct waste back into industrial production.
In her sights are complex automotive waste materials, which can be transformed into metal alloys, renewable agricultural waste that can be integrated into ferrous processing and new green ceramics that use waste plastics.
As an Australian Laureate Fellow, Sahajwalla is also working to deliver cost effective solutions for e-waste – the world’s fastest growing waste stream – that could transform this toxic mix of plastics and metals into valuable alloys. This would use her locally deployable new technology called “micro-recycling”.
Her revolutionary approach to waste, she says, is “to always look for the beauty within”.
Sahajwalla’s initial breakthrough came more than a decade ago when she began investigating carbon reactions at high temperatures, leading to her famous ‘green steel’ making process that partially replaces non-renewable coke with waste tyres and plastics in electric arc steel furnaces (EAF). Ultimately, she aims to eliminate coke injected in EAF steelmaking altogether by using renewable agricultural waste as a carbon source.
The green steel technology achieved a major milestone recently, with its use in Australia preventing more than two million waste rubber tyres from ending up in landfill. If stacked one on top of each other, the discarded tyres would reach as high as the International Space Station.
Green steel is now in commercial production around the world, under licence to research industry partner Arrium. It is reducing coke consumption, cutting electricity usage and absorbing millions of waste tyres. As well as attracting numerous national and international innovation and science awards, green steel was named on the 2012 list of Innovations that could change the way we manufacture by the US Society for Manufacturing Engineers and prompted her invitation to become the first woman to deliver the Howe Memorial Lecture in 2013, the global steel industry’s most prestigious address.
Sahajwalla’s research is underpinned by a highly original ‘waste to value’ approach. Today’s conventional waste management processes, she says, either recycle waste – turning glass back into more glass, for example, usually with a reduction in quality and performance – or burn waste for energy.
However, by considering waste in terms of its elements and by investigating how those elements can be recombined, or reacted, at high temperatures, Sahajwalla has opened up an almost infinite number of possibilities for transforming waste into new value-added materials. An example is her recent world first transformation of laminated automotive glass into a ferrous alloy, by reacting the waste with iron oxide at high temperatures.
“What was so fascinating with that was none of the inputs were metallic. By reacting waste glass, plastic and iron oxide, the output is a metallic alloy,” she says.
Although it’s not quite alchemy, as it was understood in the Middle Ages, Sahajwalla is succeeding in transforming rubbish into valuable resources. That, she says, amounts to a manufacturing revolution and “is just as satisfying”.
“We’ve had success with green steel-making, and we can do so much more through green manufacturing. There are so many opportunities. That’s what drives me on.”