Green steel: How plastic waste and coffee grounds can be an alternative material in steelmaking

Kaycee Enerva

Kaycee Enerva


Waste such as coffee grounds and plastic can be used to make “Green Steel” according to a discovery by the University of New South Wales Centre for Sustainable Materials Research and Technology (UNSW Smart), and mining company, Molycop.

Steel is one of the most essential materials in the modern industrial world, used to make everything from bridges and buildings to machinery and cutlery. Unfortunately, traditional steelmaking is not sustainable. It requires removing oxygen from iron ore to create pure iron metal, made with coal or natural gas in a process that releases CO2. 

Nearly two tonnes of CO2 are emitted for every tonne of steel produced on average, accounting for an estimated 7 per cent of greenhouse gas emissions worldwide. 

In contrast, Green Steel – UNSW Smart’s patented technology – uses hydrogen made from renewable energy instead of fossil fuels. 

Green steel:  How plastic waste and coffee grounds can be an alternative material in steelmaking
Electric arc furnace / UNSW Smart

A process called Polymer Injection Technology uses high-temperature reactions in electric arc furnace (EAF) steelmaking to transform waste tyres, coffee grounds and plastic waste in the production of high‐quality steel.

Prof Veena Sahajwalla, the lead researcher of Green Steel, UNSW Smart, explained that the metal produced doesn’t have any memory of whether the parent material was coffee or coal. Steel is still steel.

“Steelmakers [still] have to meet … quality requirements,” said Sahajwalla. 

According to Sahajwalla, the team has proven that Green Steel is comparable with traditional steel in terms of performance. 

“If I’m going to be so bold and brave, I’d love to show that it can do even better,” she added. “It will be an interesting shift towards valuing our waste resources and thinking about those inno­vative supply chains where recycling and manufacturing can be coupled together.”

Kaycee Enerva

Kaycee Enerva

A digital content manager based in the Philippines, Kaycee Enerva has written for multiple publications over several years. A graduate of Computer Science, she exchanged a career in IT to pursue her passion for writing. She's slowly practicing sustainability through period cups, and eating more plant-based food.



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