Needless to say, I always come away from doing a review like...

Needless to say, I always come away from doing a review like this finding out much more than I knew before hand, so I don't mind spending a few hours doing so.

For instance - I've found a new AI to talk to, literally, which was unbelievably helpfulcalled Pi - would recommend to anyone.

From this I now know why low arsenic in the Fluoride is so important :

However, slag from silicon production can contain trace amounts of heavy metals like arsenic, cadmium, or lead, which can be toxic if they leach into water sources or contaminate soil.

Also I'm firmly of the opinion that the acid grade fluorspar process is relatively simple with no new technologies & so few steps that the process plant cost, value adding part of the facility will be reasonable, quick to build & similarly commission.
Could potentially be flotation circuit into vacuum filter belts or centrifuges, dryed & bagged & the product is ready to ship. All the other gear up to this point is a dime a dozen - every mine everywhere will have variations of this equipment.

And lastly, Sumitomo make silicon equipment.

Sumitomo is a large corporation with various divisions, and some of them do produce equipment and materials related to silicon production.
Sumitomo Corporation Kyushu has been engaged in the development and trial production of silicon photonic featuring optical technology.
Sumitomo Precision Products produces MEMS/semiconductor manufacturing equipment and silicon deep RIE systems.
Sumitomo Heavy Industries produces machines for manufacturing high-strength, high-quality single-crystal silicon.
Sumitomo-shi-demag produces liquid silicone rubber injection moulding equipment.
Sumco Corporation, a producer of silicon wafers, has merged with Mitsubishi Materials Corp to create a new wafer company with nearly 25% share in the blank silicon substrate market.
Sumitomo Electric is developing silicon carbide (SiC) crystals and epitaxial wafers using MPZ™ growth technology.