Waste into steel

Steel is an alloy of iron and carbon. And the source of carbon is usually coal or coke. But one researcher has gone looking for another source of carbon at the local tip where approximately 1 million tons of waste plastic is dumped each year in Australia.

“We've shown that waste plastic can do the job instead of coal,” says Fresh Innovator Professor Veena Sahajwalla from the University of NSW.

“This is exciting because there is so much waste plastic in Australia, and the world, and it can be used as a carbon resource for the iron and steel industry,” says Veena.

The steel industry supplies Australian and international companies with steel for cars, construction of buildings and bridges even your kitchen appliances.

Veena has proved the idea by testing various waste plastic materials using a laboratory scale furnace at 1,600°C.

“What we have found so far is promising,” says Veena. “We can replace up to 30 per cent of the coal with recycled plastic and we are aiming for more. It is very exciting as it will not only assist with the conservation of our resources by lowering the consumption of coal, it will also help alleviate the huge waste plastic problem.”

Currently, waste plastic from drink bottles and other containers are recycled to some extent, but 2002 recycling figures indicate that on average, only 13% of plastics are recycled. It hardly dents the amount that hits the dump.

Waste industry expert, Geoff McNeill of Resitech industries, has suggested that there are a number of plastics that can be considered for this project, particularly those that are not easily recycled through current processes.

“When plastic is treated at low temperatures it produces toxic fumes. However in steelmaking reactions, the furnaces operate at a temperature much higher than an incinerator and it is expected that virtually no toxic emissions will be produced.”

“So when your kids hit the car yards looking for their first car in a few years time, they could be looking at a product of their own consumption,” says Veena.

Veena has presented her work to the media, schools and businesses as part of Fresh Innovators – a national initiative to bring the work of early career innovators to public attention. The 16 finalists selected in the national competition were brought together at the Australian Technology Park for media and presentation training. One of the 16 will win a study tour to the UK courtesy of the British Council Australia.

The technology IP has been registered for patent protection and is currently undergoing commercialisation. Veena and Unisearch, the Technology Commercialisation arm of UNSW, are now in discussion with both Australian and Overseas steel manufacturers, as well as members of the waste plastic industry

Professor Sahajwalla is the leader of the Sustainable Materials Processing Research within the School of Materials Science and Engineering at the University of NSW. She completed her Masters in Materials Science and Engineering (Uni of British Columbia in Canada) and PhD in Materials Science and Engineering (Uni of Michigan in USA).

For interview or more information: Veena Sahajwalla ph 02 9385 4426 A/hrs 02 9567 3010

UNSW furnace to study plastics reactions at high temperatures	Electric Arc Furnace for steel making	Schematic diagram of Electric Arc Furnace
Waste Resources	Plastic Products	Plastic Products

Feeding in plastic, pulling out steel

Media release 19 September 2004

A Sydney researcher is proving that much of the coal used in steel making can be replaced by plastic.