Apple uses Liam robot to extract material from non-functioning iPhones. Apple has a policy to replace defective iPhone when you surrender it to the service center. If the iPhone is repairable service center people repair it, if it fails to work, then they return it to the Apple godown.
Finally, Apple uses Liam robot to disassemble the iPhone and extract valuable metal from it.
According to the Business Insider report Apple extracted $40 million worth Gold from damaged iPhones, and 6 million worth copper from the damaged ones.
In traditional methods, it’s expensive to extract Gold from iPhones, that’s why Apple uses Liam robot for the purpose.
You can watch above video to get an idea about it.