
DLE: DIRECT LITHIUM
EXTRACTION
Current lithium production from brine mines, most found in South America, use evaporation ponds to concentrate lithium in a solution and precipitate contaminants as the water volume is reduced. This method requires relatively high lithium concentrations, arid environments to facilitate evaporation, and large tracts of land to hold brine ponds. The average extraction efficiency of lithium using evaporative extraction is between 40-60% and can take between 12-18 months start to finish. Once concentrated, the lithium concentrate can be sent for further purification at a nearby processing facility.
Not everywhere in the world lends itself to evaporative extraction methods. Subsurface brine resources in Canada, the United States, Europe, and even certain regions of South America will require new technologies to unlock their lithium resources.
The most promising technology emerging is Direct Lithium Extraction (DLE). It’s advantageous as it does not require the evaporation of water to concentrate lithium. It selectively pulls the lithium from the water and transfers it to a new solution while the lithium-barren source brine remains relatively unchanged. The DLE technologies, developed so far, have lithium recovery values up to 70 – 95% and, contrary to conventional evaporative techniques, are suitable for lower concentration brines, potentially as low as 60 mg/L.
To put it simply, DLE is a process that can remove small concentrations of lithium from a brine containing high concentrations of other ionic impurities. However, DLE is not just one process. Different companies are developing separate DLE methods for different resources based on the chemistry of the source brine.
EMERGING TECHNOLOGIES
Four technologies are emerging as the leading processes for Direct Lithium Extraction:




Each of these DLE technologies have specific advantages and disadvantages, even within the same family of technology. It is important to note that a successful technology deployed in one part of the world will not be successful in another due to differences in brine chemistries.
When we look at evaluating the performance of each technology, we consider five key performance indicators:
These five KPI’s for DLE technologies are related in some way and feed into the overall capital and operating expenses that a technology can achieve for a given brine resource.
PRAIRIE LITHIUM'S DLE TECHNOLOGY

Prairie Lithium’s DLE technology was developed in house by scientists and engineers employed by the company. It is an ion exchange process that uses a proprietary material called Plix (Prairie Lithium Ion Exchange). The Plix material is highly selective to lithium and was developed specifically to work with subsurface brines produced from Prairie Lithium’s resource area.
Prairie Lithium is diligently working to scale the Plix technology and process to commercial production of lithium chemicals. Moving from the lab to an operational environment with a successful concept is one of the biggest challenges currently faced by DLE developers.
Below is a general schematic of how Plix takes a brine with a lithium concentration of 111 mg/L and converts it into a concentrated LiCl solution suitable for purification of battery grade lithium chemicals.
LOADING
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Fresh PLIX is mixed with lithium rich brine
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Lithium exchanges with hydrogen into the PLIX crystal structure
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The lithium depleted brine is separated from the PLIX and sent to disposal
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The lithium rich PLIX is ready for desorption

LITHIUM
RICH BRINE


STRIPPING
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Fresh PLIX is mixed with lithium rich brine
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Lithium exchanges with hydrogen into the PLIX crystal structure
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The lithium depleted brine is separated from the PLIX and sent to disposal
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The lithium rich PLIX is ready for desorption

HYDROCHLORIC ACID



SEPARATION
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The regenerated PLIX is separated from the lithium chloride solution
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Regenerated PLIX is used in a new adsorption cycle
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Concentrated lithium chloride is sent for purification and manufacturing
