Waste to wealth! Scientists develop revolutionary method using common mineral to extract 5 times more lithium from waste liquids, boosting domestic supply and promoting a greener future.
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| Challenges and opportunities: New lithium extraction method offers a path towards domestic independence but requires further development for large-scale implementation. |
Oak Ridge, Tennessee, United States, April 21, 2024:
Researchers at the Oak Ridge National Laboratory (ORNL) have developed a game-changing method for extracting lithium from waste liquids. This innovation could revolutionize the domestic lithium supply chain and promote a more sustainable future.
The new process utilizes a readily available mineral, aluminum hydroxide, to extract lithium from waste liquids generated during mining, oil production, and even used batteries. This approach offers several key advantages over traditional methods.
Firstly, the process boasts an impressive five-fold increase in lithium extraction efficiency compared to existing techniques. This translates to significantly more lithium being recovered from the same amount of waste liquid.
Secondly, the method is considerably more environmentally friendly. It operates at a lower temperature (140 degrees Celsius) compared to traditional methods that require high heat (250-1000 degrees Celsius). Additionally, it eliminates the need for harsh acids, reducing greenhouse gas emissions.
Thirdly, the process aligns with the principles of a circular economy. Instead of relying solely on new lithium mines, it leverages waste streams as a valuable resource, promoting a more sustainable approach to lithium extraction.
The secret weapon behind this innovation lies in a specific form of aluminum hydroxide – the amorphous form. Unlike its more stable crystalline counterparts, amorphous aluminum hydroxide is highly reactive, readily grabbing lithium ions from the waste liquid.
The process itself involves two key steps: lithiation and delithiation. During lithiation, the aluminum hydroxide powder acts like a magnet, attracting lithium ions from the solution and forming a stable layered double hydroxide (LDH). Then, in the delithiation stage, hot water is used to release the captured lithium from the LDH, regenerating the aluminum hydroxide for reuse. This creates a cyclical process, maximizing efficiency and minimizing waste.
Another crucial aspect of the method is its selectivity. The size of the vacancies within the aluminum hydroxide structure acts as a filter, allowing only lithium ions (positively charged) to pass through. Larger ions, such as sodium and potassium, are simply too big to fit, ensuring a high concentration of lithium in the final product.
The researchers achieved near-perfect efficiency in their experiments. A single step of the process captured an impressive 37 milligrams of lithium per gram of recoverable sorbent, significantly exceeding the capacity of previously used crystalline forms of aluminum hydroxide. Additionally, a two-step approach allows for the extraction of virtually all the lithium present in the waste liquid.
Beyond efficiency, the researchers also analyzed the environmental impact of this new method. Compared to the standard sodium carbonate extraction process, the ORNL approach utilizes less energy and materials, resulting in a significant reduction in greenhouse gas emissions.
However, there are still some challenges to overcome before large-scale implementation. One key area of focus is optimizing the regeneration process. Currently, the delithiation step transforms the highly reactive amorphous aluminum hydroxide into a less reactive crystalline form. Researchers are working on a method to efficiently convert the sorbent back to its original state, ensuring long-term sustainability and cost-effectiveness.
Another challenge lies in scaling up the process for industrial applications. While the lab results are promising, further research is needed to determine the feasibility and efficiency of large-scale lithium extraction using this method.
Despite these challenges, the potential benefits of this new lithium extraction method are undeniable. By offering increased efficiency, environmental friendliness, and a path towards domestic lithium independence, this innovation could be a major step forward in securing a sustainable future for lithium-ion battery technology and other applications that rely on this critical element.