Separation Of Lithium From Brine In An Essay.

Extracting lithium from brine yields more lithium than from recycled materials.

What is lithium separation?

Lithium separation entails various chemical processes that isolate lithium from a source sample and convert it into a saleable form of the element.

How does lithium separation work?

Mineral ore and underground brine deposits are the major sources of commercial lithium. The separation of lithium is dependent on the element’s source. The separation of lithium from brine has been chosen in this work, which is in line with the assignment task- to investigate an industrial separation technique in obtaining an element from its source.

Salars- liquid brine reservoirs are located beneath salt flats. Salars are located in high-elevation areas of Chile, Argentina, and Bolivia.

Figure 1: showing a pond with salt-rich water

 

Figure 2: showing lithium harvested from salt-rich waters

Once the lithium chloride in the ponds has reached ideal concentration, the solution is pumped into a lithium recovery facility for extraction

Figure 3: a flow chart showing the extraction of lithium from brine

The industrial separation of lithium, as shown above, involves five major steps. These include pretreatment, chemical treatment, filtration, and saleable lithium production. 

Lithium element has a melting point of 180.54⁰C. This physical property of lithium is utilized in the separation of lithium from seawater and purification through precipitation from other substances that may be present in brine. The industrial separation of elements from brine can also be used to obtain sodium. 

There are various separation methods used in extracting lithium from waste lithium-ion batteries. These include pyrometallurgy, hydrometallurgy, and direct recycling (Bae and Kim, 2021)

This separation method involves the removal of organic materials at higher temperatures via evaporation and causing cathodic and anodic reactions that make lithium water-soluble. It is from this aqueous solution that lithium is recycled. Pretreated materials are powered and calcinated. At the higher temperatures, the cathodic and anodic oxides of lithium react, forming metal oxides and carbonate of lithium

Water is added to the calcinated powder to dissolve the Li₂CO₃ which is separated from the insoluble metal oxides through filtration. The solution is evaporated to obtain Li₂CO₃. Pyrometallurgy is simple and can process many disposed lithium-ion batteries (Bae and Kim, 2021). 

The separation of lithium from lithium-ion batteries using direct recycling involves several approaches. These approaches include cathode- healing, mechanical, cathode to cathode, and electrochemical technologies. These approaches are based on recovering functional cathode particles with a minimal decomposition of substituent elements. Generally, direct separation involves separating black mass components obtained from the shredding of cells using physical processes such as gravity separation. The separated materials are recovered with minimal treatment and without chemical modifications (Gaines, 2018).

Question

Hydrometallurgy is the separation method that has been used in the stimulus material provided. Hydrometallurgy is the most lithium extraction method used. The process involves ionizing lithium using acids and bases within pretreated materials. The materials are then leached to obtain Li⁺. Inorganic acids like nitric acid, hydrochloric acid, and sulfuric acid are used. The leaching efficiency is increased by heating or initiating redox reactions using H₂O₂, H₂SO₃, and NH₂OH. After leaching, the materials are precipitated, followed by solvent extraction to obtain lithium compounds (Bae and Kim, 2021).

The physical property that is used for the separation of lithium utilizing this method is solubility. The solubility differences of the metal compounds, which are temperature and specific pH-dependent, are used to separate lithium from leached solutions. Low soluble transition metal oxides and hydroxides are precipitated, leaving an aqueous solution of Li₂CO_3, from which lithium is extracted.

Energy use

High-quality water use is required in recovering lithium from brine, which contributes to water footprint and high energy consumption. Separating lithium from disposed of lithium-ion batteries requires the use of acids or bases at a higher temperature which is energy-intensive. Thus, separating lithium from brine and the recycled materials process consumes a lot of energy.

Percentage yield of the final product

Lithium salt-water (brine) reservoirs account for up to 2600 billion tons of lithium. Approximately 7000ppm of lithium can be obtained from brine extraction. Approximately 60% of lithium can be obtained from brine extraction. Disposed lithium-ion batteries contain other materials that are not lithium. Lithium forms just a part of the batteries. In a typical separation of lithium from lithium-ion disposed batteries, a maximum percentage yield of 33.2 % of lithium is recovered. Therefore, the separation of lithium from brine yields a large percentage of lithium than the recycling process.

Environmental impact of lithium separation from brine

The Lithium separation from brine poisons the local ecosystem and results in pollution of a large amount of water that creates an adverse imbalance in local ecosystems. The industrial recovery of the element increases carbon dioxide emissions, among other greenhouse gases, to the environment. Approximately 500,000 gallons of water are required to extract a tone of lithium. This high water requirement causes an environmental depletion. The extraction process denies many trees with shallow-root systems the opportunity to photosynthesize and make them productive.

The future of brine lithium extraction

The current extraction of lithium from brine takes several months and up to two years. Therefore, the future of lithium extraction from brine is centered on the speed of extraction. New techniques of filtration that can mimic living cells are developed to filter ions in a highly selective and ultra-fast manner particularly. New technologies are being developed to increase the extraction speed of lithium from seawater sources (Fawthrop, 2020). 

Reference list

Bae, H. and Kim, Y. (2021). Technologies of lithium recycling from waste lithium-ion batteries: A Review. Materials Advances.

Fawthrop, A. (2020). This tech breakthrough could revolutionize lithium extraction | Greenbiz. [online] www.greenbiz.com. Available at: https://www.greenbiz.com/article/tech-breakthrough-could-revolutionize-lithium-extraction.

Gaines, L. (2018). Lithium-ion battery recycling processes: Research towards a sustainable course. Sustainable Materials and Technologies, 17, p.e00068.

Murodjon, S., Yu, X., Li, M., Duo, J. and Deng, T. (2018). Open Access Books | IntechOpen. [online] Intechopen.com. Available at: https://www.intechopen.com/books.

1. Kudryavtsev (2016). (PDF) LITHIUM IN NATURE, APPLICATION, METHODS OF EXTRACTION (REVIEW) A review of the world’s largest lithium deposits, made the analysis of its global production and reserves. Deposits of lithium are known in Chile. [online] ResearchGate. Available at: https://www.researchgate.net/publication/308972413_LITHIUM_IN_NATURE_APPLICATION_METHODS_OF_EXTRACTION_REVIEW_A_review_of_the_world [Accessed 11 Mar. 2022].

Royal Society of Chemistry (2011). Lithium - Element information, properties and uses | Periodic Table. [online] Rsc.org. Available at: https://www.rsc.org/periodic-table/element/3/lithium.

Sethurajan, M., van Hullebusch, E.D., Fontana, D., Akcil, A., Deveci, H., Batinic, B., Leal, J.P., Gasche, T.A., Ali Kucuker, M., Kuchta, K., Neto, I.F.F., Soares, H.M.V.M. and Chmielarz, A. (2019). Recent advances on hydrometallurgical recovery of critical and precious elements from end of life electronic wastes - a review. Critical Reviews in Environmental Science and Technology, 49(3), pp.212–275.

Sloop, S., Crandon, L., Allen, M., Koetje, K., Reed, L., Gaines, L., Sirisaksoontorn, W. and Lerner, M. (2020). A direct recycling case study from a lithium-ion battery recall. Sustainable Materials and Technologies, 25, p.e00152.

Zheng, X., Zhu, Z., Lin, X., Zhang, Y., He, Y., Cao, H. and Sun, Z. (2018). A Mini-Review on Metal Recycling from Spent Lithium Ion Batteries. Engineering, 4(3), pp.361–370.