Scientists at the CENIM are working to recover and reuse strategic metals from batteries. One of their processes makes it possible to obtain nickel, cobalt and lithium with very high yields and purity. Another procedure, also developed by the same team, recovers lithium from electrolytes in the form of salts in a simpler way, with less energy requirements and a lower environmental impact.
According to figures on the Eurostat website, nearly half (46%) of the portable batteries and accumulators sold in the EU were collected for recycling in 2022.
Lithium-ion batteries contain a high percentage of valuable critical metals, so their recovery is essential for preserving natural resources and the environment. Lithium, cobalt, nickel or graphite are critical materials with a high and growing demand. Although natural resources of them are available, their costly extraction and the undeniable environmental impact of mining make recycling a better option. Nevertheless, recycling remains one of the sector's areas for improvement.
According to figures on the Eurostat website, nearly half (46%) of the portable batteries and accumulators sold in the EU were collected for recycling in 2022. In 2022, 244 000 tonnes of portable batteries and accumulators were sold in the EU. In the same year, 111 000 tonnes of used portable batteries and accumulators were collected for recycling.
At the CSIC's National Metallurgical Research Centre (CENIM) scientists work to develop processes to recycle critical metals from the black mass of discarded lithium-ion batteries.
The black mass is the material resulting from the dismantling of the batteries and the shredding of the cells. Typically, the black mass is the mixture of the anode, cathode and electrolytes of the battery. This black mass contains lithium, nickel, cobalt, manganese, copper and graphite. The challenge is how to separate these elements so that they can be reused.
High performance and high material purity
A first process developed in the CENIM laboratories is based on the carbothermal reduction (chemical reaction using carbon) of the black mass. This process allows the recovery of lithium from the cathode, which is recovered in the form of Li2CO3. After this step, different stages are applied with the aim of producing value-added materials.
One of them is a magnetic separation process that enables the obtention of a nickel concentrate which can be used in the manufacture of stainless steels. It is also possible to recover the graphite contained in the battery cathode. The materials can be reused in other industrial processes, including battery manufacturing.
A great advantage of this first method is that metals are obtained with a purity above 98% and a high yield—98%, 92%, and 99% for nickel, cobalt, and lithium, respectively.
A second, simpler and more sustainable method
A second method, also developed at CENIM, makes it possible to recover lithium from the degradation of the electrolytes of exhausted batteries in the form of lithium salts, which can then be used to manufacture new electrolytes or to be integrated into the manufacture of new batteries.
The recovery method in this case consists of hydrolysis (chemical reaction of water with another substance), filtration, evaporation and optional heat treatment. It is a simple process, which does not require any purification steps or reprocessing of the lithium salts. Additionally, it uses water as the only reagent and low temperatures. The process recovers lithium in the form of LiF and Li3PO4.
Both procedures have been developed at the laboratory scale and tested in a batch pilot plant. They are currently patented across Europe and are part of CSIC's technological offering. The researchers are initiating discussions with industry to further develop and transfer both processes to the commercial sector.
These processes represent a breakthrough in the recovery of critical and strategic metals from post-consumer products. The increase in raw material prices, geostrategic constraints and the need to replace mineral raw materials mean that these recovery technologies using recycling processes are necessary strategies to be addressed and developed.
Furthermore, these technologies developed by the CSIC can be applied to other types of batteries—most notably LiFeP batteries (lithium iron phosphate), a widely available chemistry that could potentially replace current lithium-nickel-cobalt battery compositions.
Contact:
Marisa Carrascoso
Vicepresidencia de
Innovación y Transferencia - CSIC