Fluence Treatment Plants at Lithium Mining Operations
Arid regions where evaporative lithium extraction takes place benefit from water-saving technologies
With electric vehicles and solar power gaining momentum around the world, the demand for lithium — a main component of batteries — is growing in step. How is lithium sourced? One of the main methods is extracting the reactive metal from brine.
Lithium extraction from brine still relies globally on the low-tech method of evaporation in ponds.
In one type of lithium mining, water is first pumped into subterranean lithium deposits, where it dissolves the lithium as well as other salts and any impurities present. The resulting brine is then pumped to the surface and sent on to shallow evaporation ponds, where it takes 10-24 months for the sun to evaporate the brine to concentrations high enough for harvest.
Typically, lime is used to convert any magnesium present into magnesium hydroxide, which can be efficiently filtered out. The brine may then be further evaporated or concentrated with other methods and reacted with solvents that bind to lithium ions and separate them from other ions. The brine is then treated with sodium carbonate (soda ash), which precipitates the lithium as lithium carbonate, a standard commercial form of lithium. Once the lithium carbonate is filtered, washed, and dried, it may be further converted to lithium hydroxide using calcium hydroxide, depending on the end use.
Approximately 26,400-210,000 gallons (100-800 m3) of water is evaporated per 2,205 pounds (1,000 kg) of lithium carbonate produced, depending on the source. The vast volumes of water lost to evaporation have understandably raised concerns about the sustainability of lithium extraction, especially considering that evaporation operations require arid climates, where water already tends to be in short supply. More than 90% of the salts that crystalize are considered waste, creating potential environmental risks.
Because of these considerations, processes that can make brine waste more manageable, increase water efficiency, and accelerate lithium extraction offer significant value to the lithium mining industry. The lithium mining sector can address these challenges with advanced water treatment technologies.
Advanced Membrane Processes
Water treatment with advanced membrane processes such as reverse osmosis, nanofiltration, and ultrafiltration are used to remove impurities and improve brine quality. Reverse osmosis systems use membranes to remove dissolved salts and minerals. Nanofiltration systems use a similar membrane, but with larger pores that allow operation at lower pressures to remove divalent cations and anions. Ultrafiltration membranes have even larger pores and are used to remove suspended solids and large particles.
Reverse osmosis can purify well water used for lithium brine mining, preventing the introduction of contaminants. Although reverse osmosis cannot fully separate water from lithium, it can enhance the concentration of lithium in the brine extracted from the ground.
Ion Exchange in Lithium Extraction
Ion exchange can enhance the brine purification process, optimizing efficiency and achieving the quality required for lithium products like batteries. In the process of electrodeionization (EDI), ion-exchange membranes and ion-exchange resins remove various ions — including calcium, magnesium, sodium, and potassium — from brine. EDI can continuously regenerate ion-exchange materials with no need for chemical regeneration, setting it above traditional ion exchange processes. EDI is more energy-efficient than competing processes used in lithium brine concentration and integrates well with membrane processes such as reverse osmosis and nanofiltration in lithium recovery and purification.
Continuous EDI (CEDI) systems require less maintenance than batch processes for more consistent production and quality.
Wastewater Treatment in Lithium Mining
At lithium mining and extraction sites, there are also opportunities to improve water and wastewater treatment systems for the workers employed there. In remote workforce housing camps like one in Carlsbad, New Mexico, in the Southwestern United States, Fluence is treating the domestic wastewater that is then reused on-site for applications like toilet flushing, dust reduction, equipment washing, and even for reuse in mining operations, cutting total water use without affecting quality of life.
To address these needs, Fluence offers a proven solution. The customizable Ecobox™ modular containerized units come pre-tested and pre-engineered for streamlined logistics, quick delivery, and easy installation at remote sites with no hidden costs. These units are ideal for lithium mining operations, providing efficient and reliable wastewater treatment to support both domestic and industrial water reuse applications, enhancing sustainability and operational efficiency.
Ecobox™ can effectively treat industrial wastewater streams for reuse anywhere in the world, at a competitive cost.
Fluence Case Studies in the Lithium Industry
Fluence has earned a solid reputation in the South American mining industry as a strong, mid-size company that can deliver decentralized plants ready for service in harsh, remote environments.
Fluence has strong references when it comes to brine concentration. We provided Ady Resources Limited (Enirgi Group–Salar del Rincón) with a 50,000 GPD (2,100 8 m3/h) lithium brine purification system to reduce hardness and concentrate lithium brine. The system uses reverse osmosis to produce water to use in the manufacturing process. We also delivered a high-pressure, 792,500 GPD (125 m3/h) reverse osmosis lithium brine concentration plant to FMC-Minera del Altiplano’s Salar del Hombre Muerto operation in Argentina.
Fluence solutions can also provide drinking water. For example, we supplied an ultrafiltration plus double-pass reverse osmosis water treatment plant to Eramine, a major player in the South American lithium mining sector. The plant produces demineralized and drinking water, and provides for the reuse of service water. Fluence also provided engineering services for the development of a lithium brine oxidation operation.
Sustainable Lithium Mining and Extraction
The mining sector has many options when it comes to addressing the challenges of increased regulation, limited water access, and the need to improve environmental, social, and governance (ESG) profiles:
- Water Reuse: Reusing wastewater for various purposes within the mining operation can significantly reduce freshwater withdrawals.
- Improved Water Efficiency and Conservation: Mining operations can implement strategies to reduce water consumption, especially in arid regions where brine extraction occurs.
- Energy Sustainability: Efficient technologies such as updated membrane filtration and EDI can help reduce energy consumption.
- Reduced Chemical Usage: Processes like EDI, which use fewer and less harmful chemicals, can protect the surrounding environment.
Fluence is ready for all phases of the lithium mining and extraction process, from purification of water for mining and brine purification and concentration, to water reuse solutions that take advantage of the wastewater generated at worker camps. Contact our experts to learn how Fluence solutions can help your operations.
