aluminum carbide reprocessing 6 alum.carbide =10 alum.hydroxide
alumina from hydroxide 10 alum.hydroxide = 12 alumina
alum. ingot 8 alumina = 6 alum.ingot AND 8 alum.carbide
if you do the math each cycle gains you 2 more carbide than you started with AND 9 ingots besides

This is what happens to those who ignore chemistry for the sake of the "fun factor" :)

Al₄C₃ -> 4 Al(OH)₃
4 Al(OH)₃ -> 2 Al₂O₃
2 Al₂O₃ -> 4 Al
4 Al -> Al₄C₃

Seriously though, the mods who strive to be realistic should create recipes that correspond to mols of matter.
What I mean is that 1 aluminium ingot should be considered as equal or analogous to 1 mol of aluminium.
There is no other way to achieve realism IMO. Or you are in a hell of inconsistencies.