Catherine Brochard-Lalande, Engin Deniz, Julie Jung, Finn Lawlor, Aidan Mitha, Keagan Read and Lily Scholtens
- Community Partner: Hatch Ltd.
- Degree: Bachelor of Applied Science
- Campus: Vancouver
Global demand for batteries is expected to increase from 420 GWh in 2022 to 2,000 GWh by 2030. We need to find ways to reduce our reliance on the raw materials used in batteries by finding effective and sustainable ways to recover and reuse the valuable metals in spent batteries. This can help prevent hazardous waste from being released into the environment and reduce the high social and environmental impacts associated with mining. To address this issue, engineering consulting firm Hatch asked us to design a process to recycle 30,000 metric tonnes of lithium-ion battery black mass into valuable battery-grade nickel-manganese-cobalt hydroxides in southwestern Ontario.
Our design process and challenges
"We wanted our process to be as energy-efficient and low impact as possible."
One of our biggest design challenges was figuring out how to remove impurities from the black mass feedstock. We needed to remove various metals – including copper, graphite, magnesium, iron and cesium – to isolate our product and purify it to the specifications. This involved a lot of research on solvent extraction and ion exchange. Another challenge was scaling up processes to be viable at the large scale of our plant.
Many benchtop experiments achieved what we were aiming for, but finding the right equations to make this work at a facility with 30,000 metric tonnes of annual capacity required significant research and reaching out to our mentors at both UBC and Hatch We also opted for using a hydrometallurgical process over the more energy-intensive and market-dominant pyrometallurgical process.
The advantage of hydrometallurgy is that it can offer higher efficiency of metals recovery, is less energy intensive and produces fewer pollutants. In fact, the only air emissions released from our process is oxygen. In our proposed process, the black mass is leached with H2SO4 and H2O2 in three continuous stirred tank reactors and then combined with make-up alloy streams. Impurities are removed in three steps using solvent extraction. Nickel, manganese and cobalt are then co-precipitated to metal hydroxides and the end product is washed and dried to meet specifications for use in a new battery.
What excited us most
"As chemical engineers, we are equipped to design and build the entire process, which is very exciting."
It was exciting to bring together so many of the things we’ve been learning and working on over the past four years in a real-world context. And at the same time, it was great to have the opportunity to learn so many new things. We had little prior experience of metallurgy, and this capstone project opened up a whole new area of chemical engineering for us. In terms of impact, it was very inspiring to work on a project to transform used batteries into new batteries – and in doing so helping reduce the need to mine raw materials.
Using hydrometallurgy over pyrometallurgy reflects our full life-cycle perspective on this process. There is little point in recycling batteries if you are going to be producing significant pollutants and using large amounts of energy to do so. Finally, it was rewarding to work on the design of the plant itself once we had figured out a viable process. This included completing the design drawings, choosing and costing out the needed equipment, determining the position of each area of the plant, and identifying the piping and other systems that need to be in place.
Our project’s future
The project report we submitted to our client has about 30% of the design detail you’d need to build a feasible plant. We’ll see what Hatch decides to do with it! We are very proud of the work we’ve done and it’s exciting to know that there is a real need out there for projects with this kind of impact.