Nothing like a thought exercise on extracting Lithium from the ocean....
Manono has 400 MT @ 1.65% (16,500ppm) Li2O. This gives 6.6 MT of Li2O or 3.08 MT of elemental Li. My comparisons assume 100% recovery of the Manono lithium (which I know isn't possible, it's late and I'm being "efficient").
The ocean (from a quick search) has a concentration of 0.1-0.2 ppm of Li. Let's go on the high end with 0.2 ppm. The mass of seawater required to equal the lithium in the currently defined resource at Manono would be 15,400,000 MT. Let's take 1 tonne of water to equal 1.02 m3 so this would be a volume of 15,708,000,000,000 m3. How much water is this exactly?
The largest wastewater plant in the world (Lyuberetskiye wastewater treatment facilities in Moscow according to Wikipedia) treats 3 000 000 m3 per day. This is 14,345 years of flow.
How about in our backyard? Largest WWTP in Australia is the Eastern Treatment Plant in Melbourne that gets about 41% of the city's sewage. It treats 485 000 m3/day. This is 88,733 years of flow.
Everyone's favourite liquid comparison, Olympic Swimming Pools! You would need 6.28 billion pools - not quite 1 for every person on the planet.
Let's go for an equivalent LOM (20 years). This would require an annual water transfer of 785,400,000,000 m3.
The single highest flow pump in the world can move 60m3/s (at a low head of 0.5-5m as it is a propeller pump). This would require 415 pumps of this size running 24/365 - the pumps also consume 4,000 kW at their most efficient point, so this would require 1,660 MW of power input.
Olympic swimming pools again...this would require processing 314,160,000 per year.
As a fun aside, apparently the oceans are 1.332 billion cubic kilometers in total volume, which equates to a lithium reserve equal of 39,572 Manonos.
Ignoring the frankly incomprehensible scale of the numbers here, the water will need to be processed, either with chemical or physical separation techniques. There's also the issue of sea water containing other contaminants/elements and can't be assumed to be homogeneous. A quick search suggests that it's a possible option however no-one appears to be doing this commercially and efforts are either lab or pilot scale. The low concentration of seawater (0.2ppm of seawater vs 300-700ppm for typical brine deposits vs 16,500ppm of Manono) is what will stop it from being a viable option at this point. Let's entertain the seawater option; as you extract the lithium, the concentration will drop (albeit, slowly) so progressively larger volumes would be required each year. Until hard-rock and brine reserves run out, tapping into the ocean's reserves makes little to no economic sense just purely from the mind boggling scales required to match the production from current technologies.
So, how big an issue was the transport out of the DRC again? If Manono will "never be mined" due to a few km of roads and rail, 15.7 trillion cubic meters of the ocean is sure as hell not being processed.
P.s. It's late and I'm liable to have got something out by a factor of 10,100 or 1000. Regardless, you get the point. You need an absolutely incomprehensible volume of seawater to get access to the lithium that will come out of Manono. DYOR, DYEL, etc,etc.
AVZ Price at posting:
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