"Extraction rope" technology is expected to solve the problem of lithium mass production



Lithium as one of the important raw materials for batteries, most of them are currently taken from the lithium salt lake extraction process, the whole process is cumbersome and time-consuming, but also requires a large amount of land and space, bringing huge environmental costs. For this resource-intensive, high-cost process, the United States Princeton University, a research team recently developed a new rope-based lithium extraction technology, not only subverted the traditional process, and even more environmentally friendly way of low-cost lithium mass production.

The core of the "extraction rope" technology is a set of porous fibers twisted into a rope, with a hydrophilic core and hydrophobic surface, with the rapid evaporation of water on the surface of the rope, the salt concentration is getting higher and higher, and ultimately the formation of sodium chloride and lithium chloride crystals. Nature Water/Figure

No chemicals needed and saving water

The team led by Jason Ren, professor of civil and environmental engineering at Princeton University's Andlinger Center for Energy and the Environment and head of the research group, published a research report in the academic journal Nature Water stating that the core of the new technology is a set of porous fibers twisted into a rope with a hydrophilic core and a hydrophobic surface, and that by immersing the end of the rope in a brine solution, the water moves upward along the rope through the capillary tubes, and that the whole process is similar to the way that same process by which a tree absorbs water from its roots to its leaves. As the water continues to evaporate from the surface of the rope, the salt concentration increases, eventually forming sodium chloride and lithium chloride crystals.

Jason Ren says that lithium and sodium crystallize at different locations on the rope due to different physical properties. The sodium salt is less soluble and crystallizes at the lower end of the rope, while the highly soluble lithium salt crystallizes near the top of the rope. Due to the natural separation of the two, the lithium and sodium can be collected separately, where previously additional chemicals were usually required for separation.

"The whole process is like hanging an evaporation cell from a rope." Study co-author Sean Zheng, a postdoctoral fellow at the Andlinger Center for Energy and the Environment, said, "Lithium can be accessed with a significantly reduced space footprint, and more precise control of the process is also possible."

Jason Ren's team aimed to concentrate, separate and access lithium through the basic processes of evaporation and capillary phenomena, and they demonstrated the potential scalability of the technology by building an array of 100 "extraction ropes". Compared to traditional evaporation methods, the technology saves a lot of water, is easy to operate and reduces the carbon footprint even more.

"Further improvements in the future could also lead to wide-scale applications, making it an environmentally friendly solution to key energy challenges." Jason Ren emphasizes.

Saving site area and reducing time

Currently, it is understood that most of the world's lithium is extracted from brine reservoirs located on salt flats, a production method that typically requires hundreds of square kilometers of land and takes months or even years to produce lithium ready for use in batteries.

Globally, there are only a few areas with high enough initial lithium concentrations, abundant available land, and arid climates to produce lithium commercially. For example, there is only one active lithium brine extraction site in the U.S., located in Nevada, which covers an area of over 18.13 square kilometers.

Additionally, traditional brine extraction requires the construction of a series of huge evaporation ponds from salt flats, salty lakes, or underground aquifers to concentrate the lithium, a process that can take months to years. In contrast, the "extraction rope" technology is more compact and can reduce the area and time required for production, resulting in smaller costs and faster production. Notably, the new technology can also unlock lithium resources that were previously considered too scarce and rare to be commercially viable, such as abandoned oil and gas wells and geothermal brines.

In addition, the "extraction rope" technology can also be used in more humid environments, and the rate of evaporation even increases rather than decreases. Jason Ren's team has already begun to discuss the prospects of using the technology to extract lithium from seawater.

Based on current research, Nature Water estimates that the "extraction rope" technology could reduce land use by more than 90 percent, speed up the evaporation process by a factor of 20 or more, and obtain lithium in less than a month compared to traditional evaporation ponds.

"As the technology continues to innovate and mature, large-scale lithium extraction is no longer a dream. This provides new ideas for clean lithium production." Jason Ren said.

A new way for commercial lithium mass production

Luft pointed out that there are only 101 lithium mines in normal production worldwide, and hundreds of lithium mines are still being explored. According to the International Energy Agency data, the development of lithium mines between 2010-2019, from start-up to production took an average of more than 16 years. In other words, commercial lithium mass production is still a daunting task globally at present.

Jason Ren's team has reportedly formed a start-up company around the Extraction Rope technology with the goal of advancing the commercialization of the technology, and is also developing a second generation of Extraction Rope technology to achieve higher efficiency, higher yields, and better control of the crystallization process, higher yields and better control of the crystallization process.

"Our method is cheap, easy to operate and requires very little energy, making it an environmentally friendly solution," says Jason Ren. Jason Ren said, "As it becomes commercialized and eventually moves towards mass production, it could open up new ways to extract lithium in an environmentally friendly and scalable way, cracking the lithium shortage dilemma."

Colleen Blanchard, Head of Lithium and Cleantech Research at Deutsche Bank, said, "We believe there will be a shortage of lithium from time to time. Supply will continue to grow, but demand will grow at a faster rate." Deutsche Bank expects a shortfall of about 40,000-60,000 tons of lithium carbonate by the end of 2025, with the gap widening to 768,000 tons by the end of 2030. Fitch Solutions, on the other hand, expects the world to face a lithium shortage as early as 2025.

According to McKinsey data, in 2021, total lithium demand will be 500,000 tons of lithium carbonate equivalent, which is expected to grow to 2-3 million tons by 2030. In addition, less than 30% of lithium demand came from batteries in 2015, and with the accelerating popularity of electric vehicles and energy storage technologies, batteries will account for 95% of lithium demand by 2030. In the context of the global green transition, lithium supply will be earlier than expected, as soon as possible to crack the problem of mass production is undoubtedly a top priority.