"No, I didn't conceive of global expansion immediately, but as a gradual process. First recover from the war; perhaps, disarm the federal armies; build up military power; enjoy the fruits of slavery; ruin the land -- then, get more; acquire more land (maybe from weaker states) by intimidation or aggression. (Who's going to interfere?)

Repeat the above cycle with each nation conquered -- one at a time -- and in a couple of decades, we have a growing Slave empire. Strong enough to resist European objections (even if they formed an alliance)."

If the Confederacy had maintained its independence that would have been a major achievement. But they didn't have the manpower to take on the world.
Each of the European countries I listed were larger in population than the CSA.

Anyways... mechanization in farming would have been the death knell to slavery.

"Slave Empire"...don't think so.