Material reforming: Veena Sahajwalla

A sudden trade war has nearly all of us thinking about the products and produce we need, want, consume, where they come from and what international relationships make them happen. 

America is not the manufacturing powerhouse it was at the beginning of the 20th century. Neither is Australia. 

Over the years, Australia’s industry has moved from agriculture (so many sheep) to manufacturing (think the Ford factories in Geelong) to a service economy. I’m pretty sure a wealthy businessman I met thought the service economy meant lots of call centres (he worked in textiles), but it’s more like having great doctors and surgeons, Universities that compete on the world stage, amazing culinary experiences, and all those consultants doing something…though we’re not sure what, exactly. Either way, it’s a service, not a physical product. 

But perhaps we could be more. Professor Veena Sahajwalla is focused on the circular economy: a world where materials are not extracted from nature – be it underground, from forests, from oceans – but from our rubbish. Nothing is new, but everything is renewed. 

Most of us know the three ‘Rs’ to help us cut down on waste: reduce, reuse, recycle. ‘Recycle’ as the term we know today came into use in the 1960s. It means to put resources back into the manufacturing system, reclaim the waste product to be converted again into something useful. 

There’s a bit more than just the three Rs these days. There’s eight more Rs in this article by Cleanup Australia (rethink, refuse, refill, repair, resale, rent, repurpose, rot). For Veena, there is also ‘reform’ and ‘remanufacture’, in order to ‘renew’.

Veena’s work is all about how waste can become treasure. As a material engineer, she is looking deep into a waste product at the molecular level and imagining ways it can be reformed into something useful.  

Her first invention is called “Green Steel”; a polymer injection into the steel making process that created the same, if not better, product but without using coal. 

The process of creating steel involves extracting oxygen from the iron ore and adding carbon to it under extremely hot conditions. There’s more chemistry here than physics. Much of the industry uses coke (the coal kind, not the cola kind) as the carbon source for the iron. 

When Veena was studying the process, she realised that all it needed was a rich source of hydrogen to draw the oxygen away from the iron, and carbon to bond with the iron. This didn’t have to come from energy-intensive coke, which is produced by heating coal in a specialised oven for nearly a day, it could come from something that nobody wanted. 

Tyres can be retreaded to extend their life but at some point, they can no longer function safely as a tyre. They become a waste, dumped in huge piles. Or, as Veena discovered, they can be reformed as a vital component in the steel-making process. She turned the tyres into a hydrocarbon-rich polymer to be injected into a furnace, replacing the need to use coke. 

As she says, “knowing a sector that produces all these important metals like steel, you don't want to be part of the problem. You want to be part of a solution.”

The 3Rs focuses on us as individuals to do the right thing. The truth is, responsibility needs to fall to big business to make positive changes in our world. From the latest National Waste and Resource Recovery report, municipal (household) waste contributes around 18% of Australia’s total waste. The rest is commercial, industrial, construction and demolition. 

We should be impressed – 63% of the 75 million tonnes of rubbish produced across the country is recycled. But I reckon we’d all agree this doesn’t go far enough. 

Veena’s latest work, and that of her colleagues at the SMaRT centre, are looking into shifting ‘business as usual’, by introducing small-scale remanufacturing. It comes back to looking at deeply at our waste products, their molecular composition, and thinking about how those elements can be rearranged into something renewed. I suppose that’s a basic law of physics – nothing created nor destroyed, just changing form. There are no new atoms in the Universe, they just keep reforming: hydrogen to helium, helium to carbon.

Her team have come up with the idea, and built, MICROfactories. These will take the waste products that can no longer be reused, and reform them into something entirely different.