P. Paranthaman
Oak Ridge National Laboratory,
United States
Keywords: critical REE and lithium
Summary:
The demand for lithium is expected to increase drastically in the near future due to the increased usage of rechargeable lithium-ion batteries (LIB) in electric vehicles, smartphones and other portable electronics. To alleviate the potential risk of undersupply, lithium can be extracted from raw sources consisting of minerals and brines or from recycled batteries. The main goal of this research is to develop materials and processing technologies to improve the economics of lithium extraction and production from naturally occurring geothermal and other brines for energy storage applications. A novel sorbent, lithium aluminum layered double hydroxide chloride (LDH) (pure and iron-doped), is synthesized and characterized. Each cycle of the column extraction process consists of three steps: (1) loading the sorbent with lithium chloride from brine; (2) intermediate washing to remove unwanted ions; and (3) final washing for unloading the lithium chloride ions. Using a column extraction process, this team has demonstrated that optimized LDH sorbents that can achieve a recovery efficiency of ~91% and possess excellent Li apparent selectivity of 47.8 compared to Na ions and 212 compared to K ions, respectively in the brine. Li extraction time is few minutes compared to 18 months in South America (see Figure 1). Though concentration of lithium is relatively low in geothermal brines compared to lithium from Salar brines, it does not require mining and no wells have to be drilled because the brines are already being exploited for power production. LiCl in the downstream has been successfully concentrated using forward osmosis and purified using solvent extraction methods. Solvent extraction task has developed new family of selective Li extractants that operate as weak cation exchangers. Lithium has also been successfully recovered from clay mineral sulfate leachate stream and as well as recycled LIBs through solvent extraction, sorption, membrane solvent extraction, electrochemical extraction methods and processes. Solvent extraction studies on Rio Tinto high alkalinity sulfate brine as well as high alkalinity and salinity brine simulant show high preference for Li cation in the presence of sodium and potassium ions with more than 98% Lithium extraction and separation factors for Sf Li/Na>1750 and Sf Li/K >1750. Life cycle analysis and Technoeconomic analysis have been conducted on some of these approaches. We will discuss in detail about these methods. This research demonstrates that lithium has been selectively extracted from brines, minerals and recycled lithium ion batteries, thus offering the possibility of effective application of lithium salts in lithium-ion batteries leading to a fundamental shift in the lithium supply chain.