The "Brimstone process" is, from what I'm reading, still in the experimental stage. A "pilot project" was scheduled to be finished in 2025 but I can't find anything indicating the results. The process involves chemical heap leaching and just the mention of "leach" sent environmental shivers down my spine.
I am a mining historian with a PhD so I know something about how the industry works. It's always been 98% speculation and 2% production. Oh and yeah, I worked in an aluminum plant for six years.
If something sounds to good to be true it probably is. Turning ordinary "feedrock" (whatever that is) into aluminum sounds a bit fairy tale-ish to me. It is the fourth most common element in the earth's crust but also one of the most reactive. It grabs onto anything and everything and holds on tight. Breaking the bond and forcing/tricking it into binding with itself requires very special conditions and a LOT of energy. And I know this why? Because my first postgraduate work was in the sciences, primarily biology but also heavy loads in chemistry and physics. I don't know everything ... but I tried hard.