Chromium Extraction from Hard Disk Platters
Q. Is the extraction of chromium from hard disk platters economically feasible and are there any companies that you know of that are actively extracting the chromium commercially?
A. It isn't clear to us that chromium is even among the various metallic alloy elements that make up the underlayers. Even if it was, I don't think there would be enough to make it economical to recover.
That said, if you could remove it, with acid or alkaline solutions, it would have to be reformulated in a usable form like chromic acid and that is no easy task.
Best of luck.