Short note 2021

This is a big laugh. The cost problem is acknowledged but there are many other difficulties.

Biggest of all is that electric arc furnaces are big users of electricity and that current has to be delivered in a stable way. So where will they get all that electricity? From coal-fired power stations, almost certainly. So they are still using coal to make steel but in a more complicated way!

Also amusing is that the newspaper's copy reader does not know the difference between an ark and an arc. Noah's arc would be amusing

The heating up of old car tyres to make steel could one day spell the end of coal - threatening one of Australia's key exports to China.

University of New South Wales engineering and science professor Veena Sahajwalla has pioneered world-first 'green steel' technology where hydrogen and solid carbon are extracted from waste rubber to make metal.

The former judge on the ABC's New Inventors show told Daily Mail Australia her innovation, also known as Polymer Injection Technology, had the potential to one day make metallurgical coal redundant.

'Oh, absolutely. Absolutely,' she said. 'We are certainly looking at a future where the dependency on coal for steel making is completely eliminated.

What is green steel technology?

Green steel technology involves extracting hydrogen and carbon from waste tyres to make metal

This method, also known as Polymer Injection Technology, relies on an electric ark furnace instead of a traditional blast furnace powered by coking coal

'So the goal very much is to say that we want to get to zero coal and coke in the process of making steel.'

China, Australia's biggest trading partner, last year bought $10billion worth of Australia's metallurgical coal exports and it still relies on old-fashioned blast furnaces that are heavily dependent on this fossil fuel.

'It's basically asking the question: "Where will the tipping point be for many countries like China and others?",' Professor Sahajwalla said.

Most of the world's existing steel production involves heating coking coal in a blast furnace at 1,000C, but green steel technology is about phasing this out and replacing it with a new method of making liquid steel.

'A traditional blast furnace will always have coke not just from a heat point of view but coke also provides a structure - it is a solid product that sits inside a furnace,' Professor Sahajwalla said.

'The traditional coke that is used as a source in a furnace, we're talking about replacing that coke with, of course, waste tyres.

'The science shows that it works.'

A smaller proportion of steel production involves electric ark furnace which uses high-current electric arcs to melt scrap steel and convert it into liquid steel.

Green steel production relies on this method to turn rubber tyres into metal.

Newcastle mining materials supplier Molycop, a former division of Arrium, uses green steel technology to make replacement metal wheels for Waratah trains servicing Sydney, Newcastle, the Central Coast, the Blue Mountains, and Wollongong.

Michael Parker, the company's president, said its manufacturing, combining coking coal and oil with crumbed tyre rubber and the use of renewable solar energy - to power an electric ark furnace - produced 80 per cent less carbon emissions than traditional steel making.

The green steel method, for now, has significantly reduced the need for coal in steel production but is has not completely eliminated it.

'This polymer injection technology allows us to substitute probably about half of that with crumbed rubber,' Mr Parker told Daily Mail Australia.

'Use the carbon and hydrogen out of waste tyres to replace virgin, raw materials.'

As part of the green steel production, tyres are put into a high-temperature electric ark furnace to extract hydrogen so iron oxide can be turned into iron as part of a chemical transformation. 'It's the rubber that contains all these other elements,' Professor Sahajwalla said.

'It's the tyres that give you these other molecules like hydrogen which then participates in the reaction and that's what allows us to convert the iron oxide into iron which is what becomes steel.'

The finished product sold to customers depends on added alloys and additives.

Though rubber tyres can replace the need for coking coal, a lot of the success of green steel will also rely on recycling existing scrap metal.

Mr Parker said waste metal was unexpectedly in short supply. 'There's not enough scrap steel in the world to replace the demand for new steel,' he said.

British billionaire Sanjeev Gupta hopes to use renewable energy and scrap metal recycling to turn the old Whyalla steelworks in South Australia into a major supplier of new green steel.

He has a long-term plan to phase out old-fashioned blast furnaces and replace them with electric ark furnaces.

His GFG Alliance bought Arrium, which previously owned Molycop, before American private equity group American Industrial Partners rescued it in 2017.

Professor Sahajwalla said green steel was slowly replacing coking coal. 'Ultimately, the goal is full replacement,' she said. 'Are we already on that journey? The short answer's yes.'

Unlike coking coal, tyres can also produce hydrogen, which can be turned into gas or a liquid.

Nonetheless, Mr Parker conceded green steel production, involving an electric ark furnace instead of a traditional blast furnace, was still a costlier method of making steel than coal or iron ore-derived methods.

'The issue is the cost of producing hydrogen through electrolysis is very high so there's got to be some breakthrough technically to get it down to a cost where you can afford to use hydrogen to make or produce iron ore to go into something like an electric ark furnace,' he said.

Making steel out of old tyres at least solves the problem of landfill. 'It's about being clever, let's use it in a way that maximises value from this waste,' Professor Sahajwalla said.

https://www.dailymail.co.uk/news/article-9066539/Revolutionary-green-technology-using-old-car-tyres-make-steel-spell-end-coal.html