RE: RE: air ships For what its worth:
Chromite is an iron chromium oxide: FeCr 2 O 4.
That's why Smelting was not mentioned. Rather High Temp Melting to reduce the Oxygen is better called PyroMet treatment as sulpher is not involved.
There is a possibility than some significant Chromites contain some PGMs which may be concentrated during melting & recovered as in the Norway HydoMet Ni Cu Co PGM Au Ag Refinery.
Some Chromites with PGMs can be mined selectively as in S Africa.