Simulation improves battery recycling

March 31, 2021 // By Nick Flaherty
Simulation improves battery recycling
Researchers at Aalto University are conducting life-cycle assessment to determine the actual carbon footprint of battery recycling.

Researchers at Aalto University in Finland are using a simulation-based life-cycle analysis to look at the environmental effects of a hydrometallurgical recycling process for battery recycling.  The analysis considered energy and water consumption, as well as process emissions.

“Battery recycling processes are still developing, so their environmental footprints haven't yet been studied in detail. To be beneficial, recycling must be proven to be more ecological than producing raw materials- we can't just assume recycling is automatically better, even though we know mining the raw materials has large environmental impacts, like high energy and water consumption,” said Mari Lundström, Assistant Professor at Aalto University.

Battery recycling often uses smelting, which typically loses lithium and other raw materials. New hydrometallurgical processes, which separate battery metals from waste by dissolution, enable the recovery of all metals but consume large amounts of energy and chemicals, and often produce contaminated wastewaters.

According to the results, the carbon footprint of the raw material obtained by the recycling process studied is 38 percent smaller than that of the virgin raw material. The difference is even greater if copper and aluminium recovered during mechanical pre-treatment are included. The results also point to problem areas.

“Life-cycle analysis identifies the areas where recycling can be improved. For example, we noticed that using sodium hydroxide as a neutralizing chemical significantly increases the environmental load of our process,” said Marja Rinne, a doctoral student at Aalto University.

This analysis is rarely done for battery recycling but can be done before new processes are taken into use. It is useful for determining how certain choices or process parameters affect the environmental impacts of a process, so it can be a beneficial decision-making tool for both industry and policymakers. “Simulation-based life-cycle analysis can be used even at the design stage of recycling processes to assess the environmental impacts and find the best possible options,” said Lundström.

The potential benefits of finding the best recycling processes are substantial; the EU aims to recycle 70 percent of the mass battery waste by the end of the decade. It is also setting targets for specific metals used in batteries: 95 percent of cobalt, nickel and copper, and 70 percent of lithium must be recycled by 2030.

It is estimated that the global lithium battery recycling market will be worth $19bn by 2030. Now is the time to develop alternative recycling methods, as the amount of battery waste will skyrocket with the rapid growth of electric cars, says Lundström. “We will have a massive need for recycling, and we have to find the most viable and ecological recycling processes. Research into technological innovations and their environmental impact go hand in hand,” she says.

In the study, the team also assessed the industrial scalability of the process and made recommendations on how to best modify the process accordingly.

www.aalto.fi

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Picture: 
PHOTO: VALERIA AZOVSKAYA/AALTO UNIVERSITY

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