Ann: Pilot Hydromet Plant Delivers Exceptional Recoveries of MREC, page-13

All comes down to recoveries

so from the inner spiral to the outside

by specific gravity equivalent

oversize(low inertia) by memory
monazite
zircon
rutile
illmenite
leucoxene
quartz

so if you tio2 minerals like leucoxene are tiny, your recoveries are crap, zircon not as bad ie SFX, because the SG is larger but this is assuming same grain size.

mineral technologies is the only company with a spirals, maybe edi downer had some at one stage.

the clay size particuls matter also, to how easy the minerals can be washed of clay before hitting the spirals

there are other things that help besides spirals to deal with oversize quartz removal like Derrick screens and bubble flotation (can't remember the name)

Everything is possible, it's just slower and less economic the more Capex opex to process such fine grains ?