My read is that the Lithium Salt being referred to is indeed Lithium Phosphate (Li3O4P). The latter paragraph mentioning the possibility of PLS independently building and operating it's own Li3O4P operation all but confirms the chosen salt.
As you mentioned, Li3O4P is considered by some to be the best precursor for LFP (LiFePO4) cathode production. From a chemistry POV it makes sense but also financially given the upstream feed, be it brine (POSCO using a Li3O4P process at SDV North in Argentina), hardrock, or sedimentary can avoid further costly processing to Li2CO3 or LiOH.H2O.
Lithium Australia (LIT) has had a particular focus on Li3O4P with several methods developed depending on feed. Their LieNa process most closely resembles what PLS appears to be working towards with Calix (CXL) as it deals with Spodumene as a feed. The LIT approach is to avoid traditional decrepitation via calciner (kiln) using a caustic digest method
The Calix approach PLS is investigating uses a different type of calciner to traditional converters and is not only able to deal with very fine material (potential for processing what may end up in tailings) but crucially is electric, not gas or coal fired.
This is an environmentally friendly process, even moreso if coupled with renewable energy (PV would appear suitable for the location) and as such a pathway towards a Zero Carbon Lithium product (Yes I am aware that term has been trademaked). Rather than a replacement, it could be an ideal adjunct to PLS's main SC6 offering; increasing the proportion of the resource utilized. Overall recoveries from PLS ore could be substantially lifted by applying this tech to product that may be destined to tailings.
Keep in mind that Li3O4P can still be used to produce Li2CO3 or LiOH.H2O if desired by customers, but it could clearly be a low cost alternative to those LiFePO4 manufacturers currently using Li2CO3. There have also been recent reports of some producers using LiOH.H2O for LiFePO4 cathodes.
Li3O4P could be a very wise choice of salt, particularly in comparison to Lithium Sulphate (Li2SO4), when it comes to a midstream product. The optionallity to sell direct to the LiFePO4 market along with customers in the EU and elsewhere looking for a precursor for Li2CO3 or LiOH.H2O production with an extremely low carbon footprint will be advantageous.
LiFePO4 cells really were the story of 2020 in my view. What once was considered a dying legacy cell type became a very low cost, extremely safe (no thermal runaway concerns), and with BYD's blade and CATL's CTP technologies, adequate range alternative for many passenger vehicle types to high nickel cells.
We are yet to see the full impact of those achievements as patent restrictions effectively confining LiFePO4 to China will begin to lift in 2022. Take the time to check out the links below, but here is an excerpt from Roskill
"Simultaneously, the limitation of LFP exports on Chinese producers will be largely removed, along with the licensing fee for non-Chinese LFP cell producers. The removal of this IP barrier could become the largest opportunity for LFP-based Li-ion batteries to rapidly gain market share in the EV market outside China."
What we are seeing with PLS evaluating the Calix tech and looking to produce Li3O4P shows a multifaceted approach to the company's future growth.
1: Expansion of Pilgan plant output and plans to restart Ngungaju while keeping some product uncontracted to take advantage of desperation from independent converters.
2: Downstream exposure to LiOH.H2O outside China through the POSCO JV in South Korea (undergoing final due dilligence).
3: Serious commitment to evaluate new processing methods unlocking recoveries and shifting downstream locally to offer a potentially carbon free midstream product to target jurisdictions like the EU and leverage exposure to LiFePO4 growth.
(20min delay)