Will a plumbago crucible conduct electricity, so allowing it to be used as the anode ?

Can a silica crucible be used with graphite anode ?

Any other material I can use for the crucible ?

sorry forgot to say, trying to make calcium

I don't think you'll want your crucible to serve as anode, because that will make it very difficult to keep the chlorine away from the calcium metal.
I found cast iron the only material that didn't either break or dissolve when melting salts at 600+ degs.

---

Hansje high in proteine and fibre!