Producing lithium is slow and dirty. Is there a fix?
A SUBSTANCE seen as critical to the green energy revolution, lithium, is at risk of a future supply crunch.
Even though a recent surplus of the metal has been crashing prices, demand for lithium is set to grow by almost nine times over the next 15 years in a scenario where the world meets the Paris Agreement goals for limiting global warming, according to estimates from the International Energy Agency.
Extracting lithium from the rocks and salt water where it is found can be a slow process that often harms the environment. So a race is on to develop more efficient, less damaging production methods.
One promising area of innovation is direct lithium extraction (DLE), which can slash the time it takes to remove the metal from brine from as long as 18 months to a matter of days, or even hours.
DLE remains an uncertain technology, with daunting technical challenges to be overcome before it can be rolled out at scale.
Still, its importance to lithium’s future was underscored in October last year, when mining giant Rio Tinto unveiled a planned US$6.7 billion takeover of Arcadium Lithium, a company’s that’s been deploying DLE technology in Argentina.
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Why is lithium so important?
Lithium is a key ingredient in the batteries that power electric vehicles and store the energy generated by wind farms and solar panels. The low mass and radius of lithium atoms ensure that lithium-ion batteries can quickly absorb and store more electricity than other batteries of the same weight. The weight aspect is crucial when it comes to electric vehicles (EVs) as a lighter car will travel further on the same charge.
The anticipated surge in demand raises the risk of future supply bottlenecks that could inflate prices of lithium and potentially slow the global shift to EVs. Hence the search for more efficient extraction methods that could open up new, commercially-viable sources of the metal.
What are the traditional ways of producing lithium?
Lithium is a soft, silvery-white metal in its pure form, extracted either from rocks or from lakes of salt water that are common in elevated expanses within mountainous regions – mostly in Latin America or in the west of China. It needs to be processed further into a fine powder – usually lithium carbonate or hydroxide – before it’s added to batteries.
Extracting lithium from rock requires several stages of processing to remove unwanted materials and get at the mineral. These include a technique known as leaching, in which the ore is bathed in sulphuric acid to extract the lithium and convert it into a salt form.
In the second method, brine found on the Earth’s surface or sucked up from underground is pumped into a series of ponds. The lithium concentration of the solution increases as the water evaporates under sunlight. Large amounts of fresh water are used to process the raw material.
What are the problems with lithium mining?
These techniques are time consuming and energy intensive, limiting the number of lithium reserves that are commercially viable. What’s more, the damage often caused to the environment is tarnishing the green image that’s an important selling point for electric vehicles.
EVs are supposed to lower the world’s carbon-dioxide emissions. But mining spodumene, a primary source of lithium, is an energy-intensive process that’s often powered by carbon-spewing fossil fuels. And there’s the risk that the sulphuric acid will leak into the local water system, posing a threat to wildlife.
What is DLE?
DLE uses new approaches to recover lithium from brine using industrial equipment rather than via the long, slow process of evaporation. Some, for example, use lithium-attracting beads. Others employ membranes that selectively filter the metal. Startups have pursued DLE for years, but the technology has only recently matured to a point at which it can potentially compete with existing methods.
Why is DLE so hard?
There are still uncertainties surrounding the technology.
Recovery rates of lithium can be low with DLE, and capital costs are high. Every source of brine is different, and that unique composition usually requires modifications in the process. The fact that each DLE project requires site-specific adjustments adds to the complexity and cost. BLOOMBERG
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