The Sustainable Materials Research and Technology (SMaRT) Center at the University of New South Wales (UNSW) has recently published three research papers, showing that waste coffee grounds and hydrogen may be utilized to produce green steel.
As governments and businesses pledged to cut carbon dioxide emissions, green steel, which replaces coke and coal, traditional materials for ore-based steel making, becomes an important topic for the steel industry along with renewable electricity and hydrogen.
In collaboration with OneSteel, the SMaRT Center Green Steel Polymer Injection Technology (PIT) uses recycled polymers (such as car tires) as an alternate carbon injectant to produce foaming slag in the steel making process.
SMaRT Center has recently released three papers on PIT, noting that industrial trials with partner Molycop have shown that various wastes can be used to produce steel in electric arc furnaces in a more sustainable way.
In conventional steelmaking process, coke and coal are important ingredients as carbon sources. In UNSW’s research, on the other hand, plastic and coffee grounds with discarded rubber tires were used as an alternate carbon injectant, which significantly improves the efficiency and energy required for the process with the element hydrogen.
“Steelmakers must adhere to strict quality standards,” remarked Veena Sahajwalla, head of the UNSW SMaRT Centre, “The metal that gets produced doesn’t have any memory of whether the parent material that went in was coal or coffee.”
“It gives you the kind of productivity requirements that any commercial operator will want. We’ve proven that it does the job at a comparable level, so we’re going to be at least sitting at an equivalent performance,” she added.
Sahajwalla went on saying that it would be ideal if coke could be completely removed from the steelmaking process, and that with a combination of materials, they would be able to take kinds of components that do the best job to finetune and customize green steel.
“This isn't a waste, it's a really useful resource,” she stated, “It’s going to be an interesting shift towards valuing our waste resources and thinking about those innovative supply chains where recycling and manufacturing can be coupled together.”