We don't need large centrifuges for casting. Small ones are good enough. They are used even in Earth gravity where it is not sufficient (higher-melting metals typically have high surface tension and need a bit of help to get to the mold; a long neck to use hydrostatic pressure is one variant, but spin-casting is another popular one).
Zero-g can have quite some advantages. Many materials, including metals, are diamagnetic, therefore they can be pushed around with magnetic fields. Youtube has demos with pieces of e.g. bismuth or other stuff on a string, or on a paper boat on water. Or you can buy kits with little pieces of pyrolytic carbon levitating above magnets, At zero-g, the metal can be melted with a lens, the liquid glob insulated with the vacuum then pushed around to the ingot mould, the mould spun up and down (two counterrotating ones can be used to avoid reaction force to the rest of the satellite, the ingots cool down while the mold spins by conductive heat transfer to the mold (which then loses heat by radiation into space during the next melting cycle). Regenerative braking can be used to retrieve most of the energy needed to spin the mould up.
For sintering from lunar regolith, see the experiment done with Fresnel lens and a desert sand. Youtube has more videos of melting sand and rock with a lens.