As the negative impacts of human activity on the climate have become apparent in recent decades, scientists have explored alternative forms of energy generation and storage. Chief among the natural resources that have emerged to meet this demand is lithium.
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However, while the benefits of lithium are well recognized, some key technical and environmental challenges persist with its extraction. This article will provide an in-depth analysis of the current state of lithium extraction and emerging technologies.
The Key Role of Lithium in the Transition to Net Zero
Lithium has become ubiquitous in the modern world and humanity’s transition to net zero carbon emissions. Present in a multitude of electronic products, lithium is integral to batteries for use in key green technologies, such as electric vehicles, solar panels, and wind turbines.
Lithium’s high energy density and lightweight nature make it the ideal candidate for high-performance energy storage batteries. Lithium-ion batteries, the leading technology that exploits this key resource, have benefits such as high stability and longevity, low self-discharge rates, high voltage capacity, and rechargeability.
Technical evolution is not the only factor driving this increased demand for lithium extraction. Environmental regulations encouraging the move from fossil fuel exploitation in transportation and energy also play a crucial role.
Many experts believe lithium is crucial to sustainable development and the circular economy. Due to the mineral-rich nature of the current transition to a more sustainable future involving widespread electrification and technological evolution, lithium demand is expected to increase in the coming years.
Current Lithium Extraction Methods
Lithium is found naturally in brine aquifers, clay deposits, igneous rocks, and seawater as dissolved minerals. The primary economic sources of lithium are rock ores and brine, with brines accounting for around 60% of global production.
Current extraction is performed via one of two main routes: mining and surface brine extraction.
Ore mining is an expensive and time-consuming process, requiring exploration and geological surveys before the start of extraction. Heavy machinery use and widespread environmental damage are vital concerns for environmentalists.
While less geologically and environmentally intensive, brine extraction still requires vast amounts of water. Lithium brine is pumped to surface pools, mixed with chemicals, and allowed to evaporate, with the separated and concentrated lithium salts then collected and processed into useable materials.
Chemical precipitation is the main route for lithium recovery in brine extraction. A relatively simple and inexpensive approach, pH adjustment is an essential step. Using counter-ions reduces lithium ions' solubility, with solid precipitates then separated by filtration or sedimentation.
Technical Challenges of Lithium Extraction
The efficiency of brine evaporation methods is heavily dependent on the presence of other ions and impurities, which can co-precipitate and complicate the extraction process. Magnesium, for example, possesses similar ionic properties to lithium, and both have similar radii.
Producing high-purity lithium from high Mg/Li ratio brines is a critical technical challenge for scientists working in the lithium extraction industry.
One of the most commonly used industrial extraction methods is carbonate precipitation. However, this method requires relatively high concentrations of lithium to function correctly.
Carbonate precipitation is unsuitable for newly discovered brine sources with low lithium concentrations. Therefore, a better method needs to be developed if brine evaporation is to be a future-proofed lithium extraction method.
What are the Environmental Concerns?
There are several environmental concerns linked to lithium extraction and exploitation. Mining scars the environment, and brine evaporation requires vast amounts of water and chemicals to separate precious lithium metal from liquid. Furthermore, lithium is a finite natural resource.
Current lithium extraction methods' environmental, technological, and socioeconomic challenges make finding alternative methods crucial for scientists, industry, and governmental bodies worldwide. Changing land use, resource bottlenecks, and even fossil fuel emissions hamper the green potential of lithium extraction.
Habitat destruction from mining and pollution leads to biodiversity loss. It has implications for local food chains and security for vulnerable populations who rely on local environments for food and economic income. Chemical pollution of local aquifers and rivers has a severe knock-on effect on future generations.
Addressing these environmental concerns and technological challenges is essential if the sustainability of lithium extraction and its related technologies is to be ensured. Consequently, ensuring that lithium extraction methods do not damage the environment as much as possible is a crucial pillar of the green revolution.
Due to the growing demand for lithium and an increased awareness of the environmental impact of extraction methods, many scientists and companies are developing new technologies. For example, Lilac Solutions is developing an innovative modular ion exchange method that improves extraction efficiency and reduces environmental damage and water use. Meanwhile, EnergyX is using metal-organic framework nanoparticles to provide direct lithium extraction.
In other research, ion exchange resins are emerging as a viable alternative to current methods, while scientists in Germany and the UK have explored the viability of extracting lithium in geothermal energy plants from lithium-enriched granite.
New precipitation methods have also been investigated in recent years. Studies have explored using sodium phosphate salts to improve lithium recovery rates, essential to extracting resources from dwindling deposits.
Other studies have used phosphoric acid to recover lithium from alkaline leach solutions.
However, while promising, some key challenges persist. For instance, aluminate precipitation has emerged as a suitable method in high Mg/Li concentration brines, but it is expensive and consumes high levels of alkali compounds. More study is needed to improve new advances in lithium extraction.
Exploiting Waste Streams and the Role of Recycling
Lithium is a finite natural resource, which presents a potential future bottleneck: one day, the natural reserves of lithium will run out. Therefore, to secure the long-term availability of lithium resources and the viability of green technologies, scientists are turning to exploiting waste streams and improving lithium recycling.
Recovering waste lithium to produce value-added products fits with the aims of the circular economy model and the UN’s Sustainability Goals to achieve net zero carbon emissions by 2050.
E-waste is a critical potential waste lithium source. Being a ubiquitous component in nearly all electronic products, lithium-ion batteries, and renewable energy technologies, recovering lithium from electronic products that would otherwise go to landfill and cause further environmental damage is highly attractive.
However, infrastructure must be improved to efficiently recycle e-waste and lithium-ion batteries. Moreover, the role of environmental policies which encourage recycling, reuse, and the circular economy is crucial.
Lithium is vital in the current green economy transition and the fourth industrial revolution.
Demand is predicted to escalate in the coming decades as industry increasingly electrifies and the world moves away from fossil fuel exploitation to more renewable forms of energy.
However, current lithium extraction techniques are incredibly harmful to the environment and use vast amounts of resources like water and chemicals. Furthermore, lithium is a limited resource.
In conclusion, extraction methods must be improved urgently, and emerging technologies are playing a huge part in ensuring the continuation of lithium exploitation and humankind’s transition to a more sustainable, green future.
Read More: Using Solar Technology for Ultrafast Lithium Extraction
References and Further Reading
Vega Garcia, L et al. (2023) Lithium in a Sustainable Circular Economy: A Comprehensive Review. Processes. 11:2 [online] mdpi.com. Available at: https://www.mdpi.com/2227-9717/11/2/418
Egan, T (2022) Can Lithium Mining Really be Sustainable? [online] energyx.com. Available at: https://energyx.com/blog/lithium-mining-sustainable/
Wolf, F (2021) New technologies for lithium extraction [online] mergeflow.com. Available at: https://mergeflow.com/research/new-technologies-for-lithium-extraction