Replacing coke with coffee: researchers find new uses for waste in steelmaking

Researchers from University of NSW Sydney’s SMaRT Centre have published new research showing the potential of coffee grounds and other waste as inputs in electric arc furnace (EAF) steelmaking. 

In a statement on Friday, the university said the work continued the progress of Green Steel Polymer Injection Technology (PIT), which was invented by SMaRT Centre’s Director, Professor Veena Sahajwalla, nearly two decades ago. PIT substitutes a portion of coke in EAF steelmaking with polymers derived from end-of-life materials such as old car tyres.

The papers demonstrate further sources of waste as a source of carbon and hydrogen in the process, UNSW said

“The metal that gets produced doesn’t have any memory of whether the parent material that went in was coal or coffee,” explained Sahajwalla.

Sahajwalla, who is also the current NSW Australian of the Year, said that the research – carried out with Molycop – demonstrated potential productivity improvements that any commercial operator would want, and has proven to do the job at “a comparable level” to what it is replacing.

“If I’m going to be so bold and brave, I’d love to show that it can do even better,” said Sahajwalla.

“We (Australian steelmakers) are leaders in the space globally. 

“We’re the first to be able to take all of these technological advances and show that it can be done.

“The ideal would be if we completely eliminate the coke… If you have a combination of materials, you get a better outcome because you’re able to finetune and customise green steel and take the kinds of materials that do the best job.”

(The three research papers can be accessed here, here and here.)

Previous iterations of Green Steel have been licenced to Molycop (the global leader in grinding media balls for mineral processing) and other steelmakers.

Molycop was awarded a $750,000 grant through the Advanced Manufacturing Growth Centre Commercialisation Fund in October last year to commercialise green steel “using recycled rubber from end-of-life tyres and other sources in steelmaking.” 

Other R&D efforts to make its steel more sustainable include R&D in partnership with Biocarbon, which is creating a specially tailored coke substitute out of agricultural waste-derived biochar. (An interview with Biochar from January is available here.)

Picture: Molycop

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