Thought I might give my take on the maths people are all looking at here. My understanding, and as also stated in the article below, that lithium in Tesla EVs constitutes 63kg of Lithium Carbonate Equivalent. Obviously depending on vehicle (and battery type) can be higher or lower
https://electrek.co/2016/11/01/breakdown-raw-materials-tesla-batteries-possible-bottleneck/
If you say take an average grade for PLS of say 1.26% Li20 at a 77.5% recovery rate, as per the DFS for the 2mtpa facility, you need 6.2 tonnes of ore to get to 6% spodumene concentrate (6.2 tonnes of ore feed *1.26% * 77.5% = 1 tonne of 6% grade spodumene). So at 2mtpa ore feed produce say 322,600 tonnes of 6% grade spodumene.
Spodumene grades theoretically 8.03% Li20, so if exporting 6% grade spodumene in effect saying 74.7% of that concentrate is spodumene -
https://www.911metallurgist.com/blog/froth-flotation-spodumene-processing-lithium-extraction. At 8.03% theoretical Li20, essentially saying Li content is 3.72% (as you divide by 2.153 to go from Li20 to Li) -
https://rocktechlithium.com/lithium-conversion-table/
So 6% grade spodumene in effect has equivalent Li of 2.79% (74.7% * 3.72%). Which means you need, as someone above correctly called, 7.5 tonnes of 6% grade spodumene to produce one tonne of lithium carbonate, as lithium carbonate grades 18.8% Li using a 90% recovery rate assumption in the conversion of spodumene to carbonate (i.e. 2.79% Li * 7.5 tonnes of 6% grade spodumene feed * 90% = 18.8% Li).
So the PLS Stage 1 production here is essentially 43,000 tonnes of lithium carbonate equivalent (i.e. 322,600/7.5)
Now if you need 63kg of lithium carbonate equivalent in a lithium battery (one tonne = 1000kg), then each tonne of lithium carbonate is good for 15.87 vehicles (1000/63). You get to about 682,500 vehicles from 43,000 tonnes of lithium carbonate equivalent above.
If just wanting to go with using spodumene figures, for each tonne of 6% spodumene concentrate you get 2.12 vehicles where you assume 63kg LCE euivalent is the battery need. At 50 kg per lithium batteries I do get the 2.7 cars per tonne of 6% grade spodumene quoted (i.e. you get to 860,000 vehicles from the 43,000 LCE number above - i.e 1000kg/50kg = 20 vehicles and then multiply by 43,000).
Close enough but the discussion herein does show the likely demand for lithium chemicals, and therefore demand for 6% grade spodumene, as EV takeup increases (and I suspect it will increase exponentially because as demand increases economies of scale kicks in, and as the EVs become cheaper, EV takeup increases further due to falling vehicle prices etc etc).
My current understanding is that current world production of LCE in 2018 was around 300,000 tonnes, and that EV sales were around 2 million units in 2018. Using say 50kg as an assumption (i.e. I could use 63kg but everyone on this thread is using 50 kg) suggests 100,000 of that LCE was for the EV's, the rest for the other uses of lithium (the other 200,000 LCE for 2018) (i.e 2 million sales * 50kg and then divide answer by 1000 = 100,000 LCE).
What is actually been suggested is that for every 1,000,000 additional sales of EVs (above the base 2 million sold in 2018) requires an additional 50,000 LCE, which translates to an additional need for 375,000 tonnes of 6% grade spodumene feed (i.e. 50,000 * 7.5). Essentially each demand growth of 1 million EV per year requires a new mine, or expansion of an existing mine, slightly bigger than PLS Stage 1 development discussed above. If some of the forward estimates I have read do come to fruition then a number of new mines (and expansions of existing mines) will be required (and obviously one assumption would be that hard rock is better placed than brine to meet that demand especially in the growing lithium hydroxide market).
https://www.benchmarkminerals.com/lithium-supply-revisited/
https://about.bnef.com/electric-vehicle-outlook/
All IMO IMO, but hopefully might help in understanding the conversions.
(20min delay)