Originally Posted by Smallville13
Interesting and good guesses. I'm gonna theorize that it's like a 'spirit world' like phantom zone inside the Black Zero where Krypton's prisoners are subjected too and contained in. After Zod speaks to Kal aboard his ship (with Lois and Faora there) he roughs him up (him dropping to his knees and throwing up blood) and then puts him in this containment skeleton prison hell vortex (where he's reaching out for Lois).
I love the sound of that so basically they dump him in the Phantom Zone. Infact I like your theory better than both of mine.