Is pursuing a second PhD in the same or related field a viable means of returning to academia after a decade in industry? I have a PhD from a reasonably good program in pure math, but I had no support from my department or adviser and so went into industry afterward. I'm unhappy with the situation, and I'd love to return to academia. The situation is a bit tricky, though, and I was wondering if a second doctorate (whether again in math or in another related area like mathematical physics) would help at all. Further complicating the issue is the fact that I've been in industry for the last decade, so my CV has hardly gotten any better than it was when I applied, or even left, grad school the first time. (The situation may be different in other areas, but there's very little you can do in industry that looks appealing to an admissions committee in pure math.) So, would applying to PhD #2 be a waste of time, or is this a weird but possible means of clawing my way back into academia?
In order to return to academia, you will need to satisfy certain requirements.


Most academic jobs require holding a Ph.D. in the relevant field. You already have one. A second Ph.D. won't help you here.
Teaching jobs require demonstrated teaching experience. A second Ph.D. won't help you here. You could certainly try to build a track record of successful teaching by getting in touch with a local community college and offering to teach a few courses - possibly even while holding your industry day job. If you are serious about returning to academia, this would be an investment, not a source of income, so you could offer to teach for little or no remuneration.
Research (and teaching) jobs require publications. A second Ph.D. won't help you here. Instead, get up to speed on current research, find a good open problem, work on it and publish some papers.
Finally, contacts will be invaluable. A second Ph.D. won't help you here. Instead, attend conferences, give presentations, get to know people, leave a good impression and hint that you would like to return to academia.


Note the common thread going through all these points: a second Ph.D. in the same field won't help you. Instead, invest your time in building the kind of portfolio (teaching, publications, contacts) that you do need.

This will likely be an uphill battle, but if you are motivated enough, then go for it. Good luck!