When the computer or phone you’re using right now blinks its last blink and you drop it off for recycling, do you know what happens?

At the recycling center, powerful magnets will pull out steel. Spinning drums will toss aluminum into bins. Copper wires will get neatly bundled up for resale. But as the conveyor belt keeps rolling, tiny specks of valuable, lesser-known materials such as gallium, indium and tantalum will be left behind.

Those tiny specks are critical materials. They’re essential for building new technology, and they’re in short supply in the U.S. They could be reused, but there’s a problem: Current recycling methods make recovering critical minerals from e-waste too costly or hazardous, so many recyclers simply skip them.