There was a study back in 2018 on the extraction of REE from...

There was a study back in 2018 on the extraction of REE from triple phosphate byproducts and phosphate rock.

https://dc.engconfintl.org/phosphates_viii/37/

REE yields from triple phosphate byproducts; amine tailings, phosphogypsum and clay (in order from greatest to lowest REE yield)

We only do phosphate rock at this stage (Not triple phosphate and its byproducts) and the best extraction they got from phosphate rock was 56% Scandium and 15% Praseodymium.

The problem with extracting these REE's is that their potential is disguised behind a lack of reliable pricing. There is no public market or futures for scandium. Prices are kept somewhat private. There are also various types of scandium products with big differences in price. It doesn't say what type of scandium it is (Oxide or 99% etc).

Scandium Oxide may sit around $5 per gram... $2.8 million per tonne of phosphate rock at 56% extraction best case. I have no idea about the cost of extraction so I can't gauge feasibility.

To be able to propose a REE product we would have to get a cost effective and consistent (yield) extraction method to be able to guarantee an economic output. Consistent extraction is difficult as there is a great degree of variability in yield.

I think REE is too risky. The opportunity cost would be potentially to forgo a strong phosphate rock market to investigate something that is quite under-researched.