Mine Canada’s E-Waste for Metals

When I tell people I work in urban mining, they sometimes (incorrectly) picture me sporting a hard hat and chipping away at old office towers with a pickaxe. In the past, the main way to obtain in-demand materials—like those precious critical minerals everyone’s fighting over—was through primary mining, digging deep into the ground in remote locations to extract them. But since 2014, in my chemical engineering lab at the University of Toronto, I’ve been plumbing another abundant source in Canada’s cities: e-waste, a term for the discarded electronics and batteries rusting in our landfills.

For a culture that’s constantly tapping on technology, we rarely think about the untapped resources inside it. Critical elements power many of our modern machines: for example, smartphone and computer circuit boards are rich in copper, gold, silver, indium and tin. Electric motors and wind turbines use magnets with high concentrations of rare-earth elements, like neodymium. And EV batteries are chock full of cobalt, manganese and nickel. Regular miners might be able to extract one or two per cent of a desired element from a small chunk of ore, but in a similarly sized chunk of e-waste—where the rocky impurities are already removed—that concentration can shoot up to 30 per cent.

If only we weren’t throwing away the very materials we desperately need. Less than a quarter of global e-waste is properly recycled, making it one of the world’s fastest-growing waste streams. According to the United Nations, we collectively produced 62 million tonnes of it in 2022 alone, an increase of 82 per cent since 2010. By 2030, that number is expected to hit 82 million tonnes. In Canada alone, we’re projected to generate 1.2 million tonnes annually by then. When e-waste is recycled, it’s often at dangerous processing sites in poorer countries. Before the Agbogbloshie scrapyard in Ghana officially closed in 2021, child workers were melting wires over open flames to extract scraps of copper and prying apart plastic casings with makeshift tools to reach the metals inside—without protective gear. Sites like these are still operating elsewhere in Africa, as well as in China and India.

At U of T, my team is developing more efficient, environmentally friendly extraction methods, with the goal of making exploitative sites like Agbogbloshie relics of the past. Two of the most commonly used techniques are pyrometallurgy (i.e., smelting) and hydrometallurgy (my Ph.D. focus), which has a relatively small carbon footprint and uses acid or alkaline solutions to dissolve metals at lower temperatures.

Another approach with a lot of promise is supercritical fluid extraction. The technique isn’t new: it’s already used in coffee decaffeination and the production of medical-grade cannabis. But my lab is the first in the world to adapt it for metal recycling. We capture carbon dioxide—either from the air or from industrial sources, like cement production—to be used as a solvent. Once pressurized and heated, the CO₂ can extract metal without needing acids or creating hazardous byproducts. That CO₂ can also be reused repeatedly, making the process even cleaner. We’re still in the pilot phase, but our process already has demonstrated success in extracting metals from magnets, fluorescent lamps and lithium-ion and nickel–metal hydride batteries.

Canada has the scientific talent to be a global leader in urban mining but, right now, we’re not at the front of the pack. In the 2010s, for instance, the Chinese government and several private recyclers invested roughly $13 billion to build 49 sites for collecting and recycling urban waste, with a combined capacity to process more than 40 million tonnes each year.

Japan also offers a solid model for turning high-volume e-waste recovery into national policy. In 2022, the country passed its Economic Security Promotion Act, which allowed the Japan Organization for Metals and Energy Security, a government-owned entity, to fund critical-mineral projects. One is a pilot program to build a fully independent supply chain for lithium-ion batteries via recycling. Initiatives like this have enabled resource-poor Japan to recover metals like indium, tin and tantalum from e-waste so effectively that its domestic urban mining efforts now account for more than 10 per cent of the world’s metal reserves.

The good news is Canada isn’t starting from scratch. Through the National Research Council’s Critical Battery Materials Initiative, researchers are collaborating on R&D with Canadian and German universities and businesses to commercialize better lithium-ion battery-recycling processes. Natural Resources Canada is also exploring ways to recycle magnets and improve metal extraction from both ores and e-waste. Still, it’s going to take hundreds of millions of dollars of investment in infrastructure and training to make methods like supercritical fluid extraction standard practice. In my lab, we’re performing it with small, 200-millilitre reactors, supported by an array of pumps, vessels and carbon dioxide delivery and control systems. At an industrial scale, however, supercritical fluid extraction requires entire plants built around high-pressure reactors that are sometimes thousands of litres in size.

Everyday Canadians have a role to play at the start of the urban mining supply chain: collection. Many people still don’t know what to do with their old phones or broken appliances and, as a result, a measly 20 per cent of e-waste in Canada is properly collected and recycled. Some tech companies, like Apple and Dell, offer buy-back programs and handle material recycling internally, but that isn’t happening widely enough. And many technologies, like wind turbines and EV batteries, are still so new that we haven’t yet figured out what happens at the end of their life cycles.

To prevent these objects from languishing in landfills or catch-all kitchen drawers, we’ll need to build large, warehouse-style facilities all across the country where they can be sorted, cleaned and shipped to the right processing places. Each facility would easily need to employ dozens of urban miners, thus creating thousands of jobs—and a brand new Canadian workforce. (Plucking metals from our own phones in addition to the Arctic would give us a leg up against China and the U.S. in the Great Critical Mineral Race, too.)

Urban mining won’t outright replace Canada’s traditional mining industry, but it can complement it, reducing our reliance on imported materials and moving us toward a more circular economy. I’m in the process of incorporating a startup to commercialize our lab’s urban mining method in partnership with U of T. If even a third of recyclers incorporated this technology around the world—making use of billions of dead devices—it could drastically clean up our cities. Innovating isn’t just about what we throw away; it’s also about what we choose to keep.

Gisele Azimi is the Canada Research Chair in Urban Mining Innovations and a professor at the University of Toronto.