How to extract lithium

 By Peter Ward

The rise of the electric car has been heralded as a crucial tool in the fight against emissions and climate change, and the world would certainly be a cleaner place if we all switched from fossil fuel guzzlers. If electric cars are to be so crucial to our future, how can we ensure the resources used to build their batteries are in plentiful supply and sustainable?…

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Lithium is an integral ingredient when building either an electric car, or a large scale battery system for energy storage. Two huge industries, the energy and automotive, could soon rely on a steady supply of lithium, and those gathering the resource are already feeling the strain.

Reserves around the world

The world’s total lithium reserves stand at 14,000,000 MT, according to the most recent data from the U.S. Geological Survey. Lithium can be found in large quantities in certain countries, and some of these countries are producing it on a large scale, while others are not.
In 2016, Australia produced 14,300 MT of lithium, the most in the world. The country holds over 2,000,000 MT of lithium reserves, and exports most of it to China as spodumene, a mineral ore.
The country with the largest reserves, however, is Chile, which has 7,500,000 MT within its borders, according to the U.S. Chile also holds most of the world’s “economically extractable” lithium, the Financial Times has reported, and its Salar de Atacama accounts for 37 percent of the world’s lithium reserve base. Chile is the world’s second largest producer of lithium, adding 12,000 MT to the world’s supply.
Argentina is the third biggest producer of lithium in the world as of 2016. Its production increased in 2016, reaching 5,700 MT. The South American country is expected to be an even bigger player in lithium in the future, and according to Reuters, lithium carbonate production in the country will triple by 2020. China and Zimbabwe make up the top five lithium-producing countries.

Lithium mine of Salar del Hombre Muerto, Argentina (NASA Earth Observatory, Wikimedia)

Production methods

If lithium is the new oil, then it’s best everyone understands exactly how to produce it. Lithium is the lightest metal, and found in abundance across the world, but often in hard to reach places.
Commercial lithium production has historically used mineral ore sources like spodumene, petalite and lepiodolite. But extracting lithium from this kind of hard rock is significantly more expensive than the newer method which has been introduced in recent years. Estimates by Visual Capitalist suggest the development of a lithium mine from hard rock can cost up to $40 million and take around four years. That’s much costlier than the lithium brine method, which supposedly costs $10 million during the development phase and takes 1-2 years.
Salar brines are underground reservoirs that contain a large concentration of dissolved salts like lithium and sodium. They are usually found beneath the surface of dried lakebeds, called salars. To extract lithium from these brines, the waters are pumped to the surface and into a series of evaporation ponds, where the water evaporates over a number of months. Potassium is usually harvested first from the early ponds, and then later ponds contain a larger concentration of lithium.
The lithium chloride which is left in the ponds is allowed to reach optimum concentration, before it is pumped to a recovery plant to remove any boron or magnesium. It’s then treated with sodium carbonate to create lithium carbonate, which is filtered and dried and is then ready for delivery.
But lithium carbonate is still not a battery. It is however, a white powder that can be converted into industrial salts or lithium metal.

A sample of lithium carbonate (Walkerma, Wikimedia)

Hard rock

Extracting lithium from hard rock is much more difficult and involves a number of hydrometallurgical processes. There are different ways of getting to the lithium, including crushing and heating the ore to allow the lithium to be displaced by sodium. That resulting concentrate is then cooled and made into a fine powder before being mixed with sulpheric acid and roasted again. Filtering then removed the waste, and finally soda ash is added before the lithium carbonate is crystallized, heated, filtered and dried.
There will no doubt be countless advances in extracting lithium in the future, and the major players around the world will chop and change. But the demand for lithium in electric vehicles and renewable energy storage systems is only going in one direction, so producers will need to keep up in the coming years.

READ MORE: Canadian miners and lithium by Andrew Burger

about the author
Peter Ward
Business and technology reporter based in New York. MA in Business Journalism at Columbia University Journalism School 2013. Five years experience reporting in the U.S., the U.K., and the Middle East.