Lithium Mining in the Ocean
Mining the ocean is here.
And in much cooler ways than previously imagined.
Here’s the science behind it:
As you likely know, Lithium (Li) is one of the more popular metals in circulation right now due to its ability to store much more energy than most metals and other substances.
The development of electric cars and such has led to a massive demand increase of around 180,000 tons in 2015 to an estimated 1.6 million tons by 2030.
There are about 43.6 million tons of land-based Lithium and by 2080 all of the mineable ore and brine concentrations will be exhausted.
However, in the ocean, there is an estimated over 200 billion tons of lithium. These ions are much more diluted than in places like the salt flats of South America but it’s still a nearly unlimited amount. The only issue is at .180 to .2 parts per million it is still very hard to get to with our present technology.
Current mining strategies
Most Lithium today is located in the briny salt flats of Bolivia and Argentina. Here, the concentration of Li is much higher at around 100 ppm. They even store the briny water in large evaporation ponds to concentrate it even more. This process is time-intensive and can take months to evaporate enough of the water.
But with the ocean, that’s not really an option. The amount of water and other minerals is simply staggering. Right now the best we can do is sort of filter out the ions by size.
The current strategy pioneered by materials scientists at Stanford is through electrochemical extraction where a Titanium oxide-coated Iron phosphate membrane is electrically charged. Scientists can get the lithium in but also Sodium.
Basically, the lithium ions are attracted with electricity but this also attracts sodium (Na). In order to keep as much Na out, they start with positive voltage and briefly shut it off and then turn it on again but this time with a negative voltage. They cycle this about 10 times until the ratio is about 1:1 of sodium to lithium.
The biggest issues right now are the amount of time, cycles, and energy it still takes that isn’t near enough to compete with land-based mining. But it’s just a matter of time.
Solar energy is getting cheaper year after year. Now, it’s actually one of the cheapest forms of electricity we have, the price of which has decreased about 90% in the past 10 years!
I’m excited for the other potentials of literally just pulling elements out of the sea. Operations are already underway to vacuum up nodules of other metals on the seafloor. Right now this is still in its beginning stages but more and more companies are seeking mining contracts. I believe we’ll be able to make it profitable soon, and the next step; mining space.
Stay tuned for more!