CUPERTINO, Calif. -- It took Apple less than a decade to sell a billion iPhones, but where do those devices land at the end of their life? Some of them wind up with Daisy, the second-generation ...

Inside a nondescript warehouse on the outskirts of Austin, Texas, Apple's Daisy robot has been designed to break apart iPhones so that 14 minerals, including lithium, can be extracted and recycled.

Apple has continually updated that figure in the 7.5 years since Daisy arrived. The robot now handles 29 different models, up from 18 a year and a half ago. The stark difference in cycle times between ...