How to get recommendations for PhD program when outside academia I'm looking into applying to another grad school to get another PhD, whether again in mathematics or a closely related subject. In assembling the application, where I should get recommendations from? I can't ask my advisor (I wouldn't be in this situation if he hadn't screwed me over the first time); and while there are certainly some other professors who remember me favorably, enough time has passed that I'm not sure they would have anything more than a desultory blurb to contribute. Math departments have little interest in recommendations from people in industry, and related subjects are presuambly similar. Is it possible to get some sort of recommendation or other bona fides available from industry that a PhD admissions committee in math, mathematical physics, etc. would care about?
Who did write you the recommendation letters for the first PhD? Maybe you could use them again. I think there is nothing wrong in using recommendation letters from industry, in any case. I was in the industry when I started my PhD and I showed my boss' recommendation letter, but my field is not math but physics. 
On the other hand, I agree with people that recommend you to try a post-doc instead of a second PhD.