Lithium recovery from low-grade sources such as mine tailings, seawater, and brines has gained attention due to the growing demand for lithium-ion batteries and the limited availability of high-grade lithium deposits. Traditional lithium extraction from hard rock or high-concentration brine requires significant energy and resources, making low-grade sources an attractive alternative. However, the low lithium concentration in these sources presents technical and economic challenges. This article examines pre-concentration techniques, innovative sorbents, and economic barriers while highlighting pilot projects and policy incentives that support lithium recovery from unconventional sources.

Pre-concentration techniques are essential for improving lithium recovery efficiency from low-grade sources. Nanofiltration, a membrane-based separation method, selectively filters lithium ions while rejecting larger ions like magnesium and calcium. This process reduces the volume of solution needing further treatment, lowering operational costs. Solar evaporation is another widely used method, particularly in brine sources. By leveraging natural solar energy, lithium-containing solutions are concentrated over time, though this method is slow and weather-dependent. Electrodialysis, which uses ion-exchange membranes and an electric field, has also shown promise in selectively extracting lithium from diluted solutions. These pre-concentration steps are critical for making downstream extraction processes economically viable.

Innovative sorbents have emerged as a key technology for selectively capturing lithium ions from low-grade solutions. Lithium-ion sieves, such as manganese oxide-based adsorbents, exhibit high selectivity for lithium due to their specific ion-exchange properties. These materials can be regenerated and reused, improving long-term cost efficiency. Aluminum-based adsorbents have also been tested for their ability to extract lithium from seawater, where concentrations are as low as 0.1–0.2 ppm. Functionalized polymer sorbents and metal-organic frameworks (MOFs) are under development to enhance adsorption capacity and kinetics. These materials must balance selectivity, stability, and scalability to be commercially viable.

Economic viability remains a significant barrier to large-scale lithium recovery from low-grade sources. The energy intensity of extraction processes, coupled with low lithium yields, often results in high production costs compared to conventional mining. Infrastructure requirements, such as pumping seawater or processing large volumes of mine tailings, further increase capital expenditures. Additionally, competing ions like sodium and magnesium necessitate additional purification steps, adding complexity. A cost-benefit analysis must consider fluctuating lithium prices, technological advancements, and potential policy support to determine feasibility.

Several pilot projects have demonstrated the potential of low-grade lithium recovery. In Chile, a project tested direct lithium extraction (DLE) from low-concentration brines using adsorption and ion-exchange technologies. Germany has explored extracting lithium from geothermal waters, where lithium concentrations are higher than seawater but still lower than traditional brine sources. Japan has invested in research to recover lithium from seawater using advanced sorbent materials, though scalability remains a challenge. These initiatives provide valuable data on process efficiency, environmental impact, and cost structures.

Policy incentives play a crucial role in promoting lithium recovery from unconventional sources. Governments are implementing subsidies for research and development in critical material extraction, including lithium. The European Union’s Critical Raw Materials Act emphasizes securing domestic supply chains, encouraging investments in alternative lithium sources. Tax incentives for recycling and sustainable mining practices further support innovation in this sector. Regulatory frameworks must also address environmental concerns, such as water usage and chemical disposal, to ensure sustainable operations.

The future of lithium recovery from low-grade sources depends on technological advancements, cost reductions, and supportive policies. While challenges remain, the combination of improved pre-concentration methods, advanced sorbents, and strategic investments could make these sources a viable supplement to traditional lithium supplies. Continued research and collaboration between academia, industry, and governments will be essential to overcoming current limitations and scaling up these technologies.

In summary, recovering lithium from low-grade sources requires a multi-faceted approach involving efficient pre-concentration, selective extraction technologies, and economic strategies. Pilot projects demonstrate technical feasibility, while policy incentives help mitigate financial risks. As demand for lithium grows, diversifying supply through unconventional sources will be critical for sustainable battery production and energy storage solutions.