Mineral Brine Concentration and development of Lithium Extraction Technologies

The alkaline metal’s electrochemical properties coupled with its low weight make Lithium ideal for use in batteries. Lithium is an essential element for the rechargeable battery market, as Lithium batteries can pack a lot of energy into a relatively small and light device. The United States Geological Society (USGS) estimates that batteries constitute 65% of the end-use market for lithium. Worldwide, manufacturers use more than 160,000 MT of lithium minerals annually. In 2020, 71% of that material was used to make batteries, according to data from the USGS, up from 23% in 2010, when the main applications for Lithium were glass and ceramics.
These batteries are a driving force in the modern economy, from powering personal electronics to grid storage systems and automobiles. Lithium is not a rare resource; it is found abundantly in the lithosphere and available from brines and hard rock deposits.

Current methods of Lithium mining

Currently, Lithium is mined on land. Estimates of the total amount of lithium in terrestrial sources vary widely because of differences in the way supplies of natural resources are tallied. USGS estimates it is about 21 million MT, but the same source estimates it can go up to 86 million MT when supplies of Lithium that can be mined in the near term are added. The difference reflects findings from extensive geological surveys in Bolivia, Chile, Australia, and other countries, in response to growing demand for the lightweight metal.

Historically Lithium is extracted from mineral brines using Evaporation methods. The highest concentration of Lithium in brines is found in the Lithium Triangle which is located in South America. Salar de Atacama is situated within the Lithium triangle and is classified as a marginal high desert climate. To produce concentrated brine, a low-concentration brine (~0.17% lithium concentration, which is 70% water by mass and the remainder other minerals) is pumped to the desert surface and into Evaporative ponds for around 1 year where it can be exposed to the sun and heat to facilitate evaporation to allow the extraction of various salts and increase concentrations of Lithium to around 6%. This final brine is then shipped to Antaforgasta for conversion to Li2CO3 (Lithium Carbonate). This method is less expensive than the other common industrial methods – extracting the metal from Lithium-bearing mineral ores.
Since the increase in demand for Lithium, where according to market analysts, manufacturers are on track to consume one third of the land-based Lithium in the next few decades, it has become apparent that using evaporative pond process may not be hugely efficient. Apart from the huge water loss via evaporation which is more than 60% of input brine mass it is estimated that potential loss of Lithium in the evaporative mining process is around 28% with some reporting in the industry that is could be as high as 40%. In addition, it appears that each ton of Li2CO3 requires 30m3 of water, which indeed means a radical new step in the processing is needed to reduce the risk of loss of resource and also the extraction of fresh water from already depleted aquifers.