A good discussion and just goes to show that building, commissioning and optimising a Hard Rock Lithium Plant isn't easy. Every orebody has different mineralogy that has to be dealt with and obtaining optimal recovery v SC% balance and reducing cash cost of production is a fine balance, one which many of the future producers will have to go through.
Have a look at Mt Marion. Flat out doing 4% and ongoing plant improvements are being carried out to lift that closer to the 5.5-6% SC region. It will cost money and lots of it.
The former Altura plant ( Now Ngungaju Plant ) that PLS picked up for a song. Modifications were required to improve plant recovery, not so much SC% level. This plant was struggling to get to 60% recovery when Altura were running it so it was running well below below nameplate design even though all the DFS pilot plant work indicated it would be higher. PLS spent the money and have commissioned this during the last two quarters. From the amount of SC PLS shipped during the September Quarter, I would assume this plant is now close to nameplate near 180-200kt pa.
I refer back to this PLS March Quarter Operations Update
https://1pls.irmau.com/site/pdf/24aa5069-44b9-4e79-9d32-22a9ee9d902c/March-Quarter-Operations-Update.pdf which states the amount of SC6.0 shipped for the quarter. From that I think we can assume the PLS Pilgan Plant is capable of producing 6% SC.
Now having listened to every quarterly investor conference over the last few years, I do remember some of the answers during the Q & A sessions.
KB and DH have both discussed this point several times in the conference calls and various podcasts.
From what they have said, discussions with customers about SC5.5 or SC6.0 requirements come down to this. If the customer accepts SC5.5, PLS are able to supply more LIthia units as the recovery is higher. Yes it requires more processing by the customer at their end but they actually get more Lithium.
The benefit for PLS is reduced operating costs per/t as recovery is higher. It's a win win for customer and supplier in this time of demand/supply imbalance. The customer needs every Lithia unit they can get their hands on so accepting a lower % SC makes sense.
Now I've read a bit on Greenbushes also and believe me, they are going through the same issue with balancing recovery % with SC%. Maybe 5-5.5% SC will be the new norm in this time of Lithium shortage.
And then there is the downstream processing to Hydroxide/ Carbonate and aren't Kemerton and Kwinana plants having fun commissioning those Hydroxide plants.
We'll see how the Posco / PLS JV facility goes towards the end of 2023 when they start commissioning their plant in South Korea.
(20min delay)