[Fuzz]

To extract those needles, recyclers rely on two techniques, known as pyrometallurgy and hydrometallurgy. The more common is pyrometallurgy, in which recyclers first mechanically shred the cell and then burn it, leaving a charred mass of plastic, metals, and glues. At that point, they can use several methods to extract the metals, including further burning. “Pyromet is essentially treating the battery as if it were an ore” straight from a mine, Gaines says. Hydrometallurgy, in contrast, involves dunking battery materials in pools of acid, producing a metal-laden soup. Sometimes the two methods are combined.

Each has advantages and downsides. Pyrometallurgy, for example, doesn’t require the recycler to know the battery’s design or composition, or even whether it is completely discharged, in order to move ahead safely. But it is energy intensive. Hydrometallurgy can extract materials not easily obtained through burning, but it can involve chemicals that pose health risks. And recovering the desired elements from the chemical soup can be difficult, although researchers are experimenting with compounds that promise to dissolve certain battery metals but leave others in a solid form, making them easier to recover. For example, Thompson has identified one candidate, a mixture of acids and bases called a deep eutectic solvent, that dissolves everything but nickel.

Both processes produce extensive waste and emit greenhouse gases, studies have found. And the business model can be shaky: Most operations depend on selling recovered cobalt to stay in business, but batterymakers are trying to shift away from that relatively expensive metal. If that happens, recyclers could be left trying to sell piles of “dirt,” says materials scientist Rebecca Ciez of Purdue University.

https://www.sciencemag.org/news/2021...dead-batteries


A few other good points made here. With millions of EV's out there already, is this going to be a bit of a disaster in a decade? Glueing cells together doesn't seem like any thought has been put into the recylcability of these things. I wonder if we will be paying EV disposal fees, or deposits in the future.