Lithium batteries – recycle, rethink
Written by Zachary Gray, BEng.Biosci, Chemical Engineering & Bioengineering
Electricity is in, and fuel is out — The Royal Dutch Shell’s 50-year plan is in motion. Much to long-time shareholder’s chagrin, the 112-year-old global behemoth is pivoting their business model away from fossil fuels in the decades to come in favour of more sustainable forms of energy, including wind, solar, and hydrogen.
The Royal Dutch Shell transition is not limited to ethereal boardroom speak, placating the dry martini-sipping corporate climate change activists, but aligns with the tenets of the Paris Accord and emerging trends in consumer behaviour: more electric vehicles and charging stations, less crude oil.
Indeed Canadians with ambivalent, and often geopolitically divergent attitudes towards their energy sector are purchasing electric vehicles (“EVs”) at an accelerating pace: EV sales increased 125% from 2017 to 2018, putting an additional 100,000 on our roadways.
The problem to avoid is exchanging one environmental sin for another. There is a greater understanding among the general road-faring population that the fuel they are pumping into their cars, on the way to doing more important things with their time, combusts, adding to the greenhouse gases accumulating in the atmosphere.
Meanwhile, charging one’s EV adds a degree of separation between drivers and their energy source.
Generally, driving an EV in Ontario, where 93% of the province’s energy comes from carbon-free sources, is far better for the environment than the combustion box on wheels sitting in the queue at the Shell station.
Not so much in Kentucky, where 92% of the state’s energy comes from low-energy-density coal; or worse: Illinois, Ohio, Indiana, or Texas, where they burn far more to keep the lights on – or, EVs cruising along their streets.
An EV’s positive environmental impact is only as good as its energy supply and battery.
Often, the EV’s greatest sin is its battery. In a study comparing Tesla’s Model S alongside a comparable internal combustion engine vehicle, the former’s manufacturing process generated 15% more greenhouse gas (“GHG”) emissions.
Despair not, however, the same study acknowledged that a Tesla generally rack up fewer GHGs over its lifespan compared with the latter.
For context, Tesla’s position is far better than the first generation of Toyota’s hybrid vehicle, the 1997 Prius. Between mining nickel for its catalysts in Northern Ontario and the spiderweb of trans-continental shipping bringing together the car’s disparate components across Toyota’s decentralised manufacturing sites, the first Prius’s GHG emissions over the course of lifetime dwarfed those of military-grade Hummers – which, some readers may be surprised to learn, are not known for their fuel economy.
Tesla’s cathode and electrolyte are its central issues.
There are three components to EV’s lithium-based batteries: the anode, made from graphite; the lithium electrolyte; and cathode, often a mixture of nickel, aluminium, and manganese cobalt. Tesla’s cathodes, a combination of nickel, cobalt, and aluminium, are the main environmental culprit; the lithium is salt on the wound.
Analysts estimate that Argentina, Bolivia, and Chile hold 15% of the world’s lithium reserves.
Abundance, however, is not the problem: water usage and isolation are. Clean water is scarce high in the Andes, and mining operations use immense volumes in their salt brine ponds to separate the lithium from magnesium and potassium that are also present.
Lithium brine ponds now litter the famous Salar de Uyuni salt flats.
While TIME magazine may celebrate the wealth potential, and the relative cleanliness of lithium mining throughout these South American countries, consumers should remain vigilant to ensure extractors are not given carte blanch over the region’s resources – besides, who gets a medal for not placing last?
For some perspective, the Guangdong province in China used mining to further its economy, much like the three South American nations are doing, feeding the world’s growing appetite for electronics with its vast supply of heavy metals – perfect for batteries and processors.
Now, it costs US$29/kg to remediate soil in the region. Nor do few publications outside of Canada’s right-wing press celebrate the economic value which the Oil Sands mines deliver to Albertans.
There is also the social impact to consider outside of the environmental damage brought on the world’s growing appetite for electronics and the batteries which keep them charged.
The Democratic Republic of Congo is one of the largest global producers of cobalt, a critical element in Tesla’s cathodes. There are also an estimated 35,000 child laborers working in the Congo’s cobalt mines.
At US$83,000 per metric tonne, the high commodity prices for this scarce metal are incentivising the less than stable Congolese government to turn a blind eye to the increasing rate of child enslavement in their country. Meanwhile, citizens in developed nations enjoy faster charging times for their phones and better performance in their EVs, for which they can thank cobalt’s presence.
That’s how it is: Fossil fuel reliance diminishes as society increasingly coalesces around electronics and sustainable forms of energy. Metals such as lithium and cobalt, play a critical part in the transition’s material infrastructure.
However controversial, mining provides the initial access to these vital materials. Consumers can take heart knowing that battery components, while not non-renewable, are recyclable – unlike the proceeding technology.
The rare earth elements can feed a closed-loop supply chain as they enter circulation while robust recycling technologies ensure their place within it.
The importance of battery recycling
Tesla ensured that recycling as part of its battery’s supply chain. The company recycles 60% of spent cells from its cars, reuses a further 10%, and landfills the rest due to technical difficulties.
They use Kinsbursky Brothers in North America and Umicore in Europe. Both of these recyclers use traditional furnace techniques called pyrometallurgy to process the spent batteries.
Four high-level events place during the pyrometallurgical process; they are:
- Preparing the furnace load, including the battery components and coke
- Treating the off-gas, filtering the batteries’ vaporised plastic parts, before discharging to the atmosphere
- Removing slag from the kiln, including aluminium, silicon, and iron
- Completing the smelting process.
The resultant product is a copper, lithium, cobalt, and nickel alloy, representing 40% of the batteries contents, while the treated off-gas and slag account for the remaining 60%.
For reference, a Model S has 7,100 battery cells, weighing 540 kg, meaning that the heating-based approach recovers ~220 kg of valuable cathodic materials, representing approximately 80-85% of the original amount, for the industry’s growing closed-loop supply chain.
Altogether, the pyrometallurgical recycling of lithium-ion batteries reduces GHG emissions by 70% over-using new resources, further lowering the environmental impact for the next generation of EVs.
Umicore’s process can handle 7,000 metric tonnes per year, equivalent to 35,000 EV batteries. Right now, the company is focusing on better serving smaller-scale electronics and pivoting their technical model towards less-energy intensive forms of battery recycling.
Fully embracing hydrometallurgical techniques, the process extracting metal ions from aqueous solutions and forming salts, is the new frontier in lithium battery recycling.
One Canadian company stands out in the emerging technical group: Li-Cycle.
The Mississauga-based Li-Cycle Corporation is piloting its two-step, closed-loop recycling technology in Southern Ontario.
First, the “Spoke” mechanically reduces the size of the battery’s components, leading to the “Hub,” which leverages hydrometallurgical technologies to yield high-value salts.
In addition to emitting few GHGs and expending little solid waste, the company also treats and reuses its water and acid. Encouragingly, the company achieved a >90% recovery rate for critical metals during their pilot-scale operations.
Li-Cycle’s technology minimises energy usage and operational inputs while outperforming competitor’s return.
Going forward, the company will separate the two components business units, better serving regional markets: Multiple Spokes, each processing 5,000 tonnes of used batteries per year, will supply a 15-20,000 tonne Hub.
A constellation of Li-Cycle’s units would increase the availability of critical metals from other electronics, such as cell phones, for the rapidly expanding EV market.
Tesla recently announced its concern about the impending shortage of metals critical to their batteries’ chemistry. In the future, companies such as Canada’s Li-Cycle and Umicore will be able to mediate discrepancies in the EV supply chain.
Used batteries languishing in the dump are harmful to the environment and damage the growing, technical infrastructure around recycling rare earth metals. Mining brings the batteries’ minerals into circulation while recycling keeps them in use.
Recycling will be an integral part of the EVs’ industrial arc as they proliferate in usage, while the energy paradigm continues to shift from fossil fuels to sustainable forms of electricity and new generations of battery technology minimise the use of precious minerals.
Source: HazMat Magazine