Lithium Extraction Research Articles

Molecular insight into the separation mechanism of crown Ether-Based channels for lithium Extraction

The shortage of lithium resources can be effectively improved by using membrane separation technology to extract lithium from salt lake brines that contain rich Li. In this study, GO modified with functionalized crown ether group (2)-hydroxymethyl-15-crown-5,15C) was used as a separation membrane for Li+/Mg2+. The effect of 15C and its content on the separation mechanism of Li+/Mg2+ in membrane was designed and studied by molecular dynamics simulation. Improving water permeability of the membrane can be achieved with the appropriate amount of 15Cs, but an excessive amount of 15C will result in channel obstruction, which is not conducive to the transport of water molecules. In addition, the special recognition of Li+ by 15Cs enhances the transmission of Li+ within the channel. Finally, it is found that the dehydration behavior of Li+ is facilitated by the interaction between 15Cs and Li+. As the diameter of Li+ is smaller than the diameter of the 15C cavity, dehydrated Li+ passes through the 15C cavity with ease under pressure. This means that during the separation process, Li+ enters a “dual transport” mode. The membrane gains higher permeability for Li+ while blocking Mg2+. This study clarifies the rapid transport mechanism of Li+ in GO-15C，which provides a feasible strategy for designing highly selective Li+/Mg2+ separation membranes.

Highly selective lithium extraction from salt lake via carbon-coated lithium vanadium phosphate capacitive electrode

Recently, with the rapid development of lithium-ion batteries and electric vehicles, the demand for lithium resources in the world has undoubtedly greatly intensified. Based on the advantages of high selectivity and low energy consumption, capacitive deionization (CDI) technology is well-suited for the selective extraction of lithium resources from salt lakes. Herein, carbon-coated Li3V2(PO4)3 (LVP@C) is developed as a cathode electrode for the first time by using a hybrid CDI device to selectively extract Li+ ions from salt lake brine, due to its high theoretical capacity and excellent cycling capacity. The electrochemical (de)intercalation mechanism of Li+ ions in the LVP@C has been evaluated by electrochemical, X-ray photoelectron spectroscopy (XPS), and in-situ X-ray diffraction (XRD) techniques, demonstrating a reversible transition of the V valence state during electrosorption/desorption based on Faradaic redox reaction. The optimized LVP@2C delivers a maximum Li+ electrosorption capacity of 25.8 mg g−1, and still maintains a high retention of 78 % even after 50 cycles. The LVP@2C has lithium selectivity coefficients of 444.7 and 351.2 at high Mg-Li ratios of 1:5 and high Na-Li ratios of 1:15. Density Functional Theory (DFT) calculations further reveal that the selective electrosorption mechanism in the LVP@2C electrode is mostly ascribed to the smaller hydrated ionic radius and lower ionic diffusion energy barrier of Li+ ions in comparison with Mg2+ ions. Finally, the effectiveness evaluation of the lithium selective extraction from the brine of a natural salt lake in Tibet indicates that the LVP@2C has highly selective electrosorption of lithium (α(Li/Mg) = 187.50, α(Li/K) = 136.11, α(Li/Na) = 116.88, α(Li/Ca) = 4.92) and can serve as a potential electrode for the extraction of lithium from salt lake brine.

Experimental Study of Lithium Extraction in the Solid-Liquid Conversion of Low-Grade Solid Potash Ore

There are considerable reserves of low-grade solid potash resources in the shallow part of Mahai Salt Lake in the Qaidam Basin, and the lithium brine resources resulting from solid–liquid conversion and mining are quite abundant. The comprehensive utilization of these resources is an important and urgent problem. In this study, to fully utilize these resources, the shallow low-grade solid potash ore in Mahai Salt Lake was used for systematic simulated ore dissolution experiments, combined with geochemical and X-ray diffraction analyses. The following key results were obtained: (1) Most Li+ in the Mahai mining area was deposited on the soluble salt minerals in silt or clay, and the appropriate concentration of solvent can help to dissolve more Li+ and K+; (2) the saturation time of Li+ was longer than that of K+. Therefore, the dissolution time for the mine can be appropriately extended during the production process to dissolve more Li+; (3) the solid–liquid conversion aqueous solution mining method can separate the lithium part of clay deposits and is associated with salt rock in the brine, which is a potential lithium resource. These experimental results provide a theoretical basis for salt pan production.

Biomimetic construction of smart nanochannels in covalent organic framework membranes for efficient ion separation

Smart nanochannels can regulate ion transport behavior by external stimulus and display precise ion selectivity in biological membrane systems, but constructing artificial membranes with responsive and tunable channel remains a severe challenge. Herein, smart covalent organic framework (COF) membranes decorated with photo-responsive azobenzene derivatives (COF-Azo) were fabricated by a biomimetic nanochannel modulation (BNM) strategy, endowing membranes with charged and switchable sub-nanochannels. Under different wavelength of light, the smart COF-Azo membranes simultaneously exhibited outstanding mono/monovalent and mono/divalent ion selectivity (K+/Li+ ideal selectivity of 17.9 and Li+/Mg2+ ideal selectivity of 24.9) via closing and opening channels. The conversion of effective pore size at angstrom level is realized by photoisomerization of azobenzene. After several photoswitch cycles, the smart membranes still maintained K+/Li+ selectivity of 6.1 and Li+/Mg2+ selectivity of 20.7 in mixed salt solution, exhibiting great potentials in lithium extraction. This work may blaze a trail in constructing photo-responsive nanochannel membranes for energy-efficient ion separation.

Fast and stable lithium extraction enabled by less-defective graphene supported LiMn2O4 conductive networks in hybrid capacitive deionization

Hybrid capacitive deionization (HCDI) technology for lithium (Li+) extraction from brine has received growing concern owing to its easy operation, low energy consumption, and environmental friendliness. LiMn2O4 (LMO) as an affordable Li+ extraction material offers a high theoretical capacity, while the slow ion insertion kinetics and unavoidable Mn dissolution restrict its wide usage. Herein, an LMO-based electrode supported by less-defective (inherent lattice defects and oxygen-containing defects), interconnected graphene conductive networks is proposed for fast and stable Li+ extraction from brine using HCDI. The rGO/LMO electrode displays an excellent conductivity of 0.42 S·cm−1 and a high specific capacitance of 418.26 F·g−1. In the HCDI system, the rGO/LMO electrode delivers a Li+ adsorption capacity up to 4.34 mmol·g−1 with a rapid adsorption rate of 0.33 mmol·g−1·min−1 (0.05 mol·L–1 LiCl, 1.0 V), demonstrating both of the outstanding adsorption capacity and rate abilities as defined by Ragone plots. In a solution with a high Mg2+/Li+ molar ratio of 20, the separation factor can reach 71.32. By employing rGO/LMO electrode to simulated Atacama brine, the separation factor of Li+ from Na+, K+, Ca2+, and Mg2+ are calculated to be 473.89, 74.86, 63.07, and 38.55. Particularly, the rGO/LMO electrode shows remarkable cycling stability with a capacity retention rate of 90.73 % (50 cycles). This developed less-defective graphene-wrapped LMO electrode holds significant importance in enhancing selective Li+ extraction performance with fast rate and stability.

Priority recovering of lithium from spent lithium-ion battery cathode powder by pyrolysis reduction of Bidenspilosa

In this paper, the invasive plant Bidens pilosa was used as a carbon material to roast and reduce the cathode powder of spent ternary lithium-ion batteries (LiNixCoyMn1-x-yO2), to alleviate lithium resource scarcity and the problems of large spent of batteries which is harmful to the environment. The transition metals in the cathode powder were reduced to Ni, Co, and MnO, respectively, and the Li element in the cathode powder was reacted to generate Li2CO3. The experiment explored the reduction effect of high valent metals in spent lithium-ion batteries at different roasting temperatures and biomass ratios, and the impact of different time on the leaching of Li element. Results showed that the optimal experimental conditions of reduction roasting were as follows: temperature 700 °C, biomass ratio 20%. The leaching efficiency of Li obtained under optimal roasting conditions through leaching was 94.15%. TG-DSC/MS, XRD, XPS, SEM, and other instruments characterized the experimental results. This method not only efficiently converts Bidens pilosa into a carbon-reducing agent and solves the problem of plant invasion, but also promotes the decomposition of spent cathode powder, reduces high valence metals to single metals and low valence oxides, and generates Li2CO3 through reaction, which can selectively extract lithium element and reduce the amount of reagent added and the use of reducing agent in the subsequent leaching process.

Lithium extraction from geothermal brines: Adsorption-desorption studies on 226Ra (228Ra) and 210Pb on lithium-titanium-oxides (LTO)

Extracting lithium from geothermal brines contributes to meet the growing demand for lithium-ion batteries and other energy applications. Deep geothermal brines of the Upper Rhine Graben (URG) contain up to 200 mg L−1 of lithium and a wide range of dissolved elements, including Th–U series radionuclides. This study presents data from a radiochemical monitoring conducted as part of pilot tests for lithium extraction at the Bruchsal geothermal site under site-specific thermodynamic conditions (T = 60 °C; p = 18 bar). The results show an uptake of the long-lived radionuclides 226Ra (228Ra) and 210Pb by the granulated lithium-titanium-oxide (LTO) sorbent employed. Increasing pH values favor the adsorption of the naturally occurring radionuclide, due to increasing negative charge of the LTO surface. The radioactive uptake of radium was found to be nearly in adsorption equilibrium state after 12 extraction cycles performed. In contrast, 210Pb is permanently removed from the Bruchsal brine by more than 96 % reflecting its high capability to approach the adsorbent surface during adsorption compared to the competing cations. Radioactive load of both radium and lead isotopes on the LTO adsorbent could be reduced using 0.5 M HCl as desorption agent. In this context, desorption percentages ranging from 50 to 100 % per extraction cycle were obtained.

Reduced Lattice Constant in Al-Doped LiMn2O4 Nanoparticles for Boosted Electrochemical Lithium Extraction.

Extracting lithium selectively and efficiently from brine sources is crucial for addressing energy and environmental challenges. The electrochemical system employing LiMn2O4 (LMO) electrodes has been recognized as an effective method for lithium recovery. However, the lithium selectivity and stability of LMO need further enhancement for its practical applications. Herein, the Al-doped LMO with reduced lattice constant is successfully fabricated through a facile one-step solid-state sintering method, leading to enhanced lithium selectivity. The reduced lattice constant in Al-doped LMO is proved through spectroscopic analyses and theoretic calculations. Compared to the original LMO, the Al-doped LMO (LiAl0.05Mn1.95O4, LMO-Al0.05) exhibits highercapacitance, lower resistance, and improved stability. Moreover, the LMO-Al0.05 with reduced lattice constant can offer higher Li+ diffusion coefficient and lower intercalation energy revealed by cyclic voltammetry and multiscale simulations. When employed in hybrid capacitive deionization (CDI), the LMO-Al0.05 obtains a Li+ intercalation capacity of 21.7mgg-1 and low energy consumption of 2.6Whmol-1 Li+. Importantly, the LMO-Al0.05 achieves a high Li+ extraction percentage (≈86%) with Li+/Na+ and Li+/Mg2+ selectivity of 1653.8 and 434.9, respectively, in synthetic brine. The results demonstrate that the Al-doped LMO with reduced lattice constant could be a sustainable solution for electrochemical lithium extraction.

Highly Selective Lithium Transport through Crown Ether Pillared Angstrom Channels.

Biological ion channels use the synergistic effects of various strategies to realize highly selective ion sieving. For example, potassium channels use functional groups and angstrom-sized pores to discriminate rival ions and enrich target ions. Inspired by this, we constructed a layered crystal pillared by crown ether that incorporates these strategies to realize high Li+ selectivity. The pillared channels and crown ether have an angstrom-scale size. The crown ether specifically allows the low-barrier transport of Li+ . The channels attract and enrich Li+ ions by up to orders of magnitude. As a result, our material sieves Li+ out of various common ions such as Na+ , K+ , Ca2+ , Mg2+ and Al3+ . Moreover, by spontaneously enriching Li+ ions, it realizes an effective Li+ /Na+ selectivity of 1422 in artificial seawater where the Li+ concentration is merely 25 μM. We expect this work to spark technologies for the extraction of lithium and other dilute metal ions.

Highly Selective Lithium Transport through Crown Ether Pillared Angstrom Channels

AbstractBiological ion channels use the synergistic effects of various strategies to realize highly selective ion sieving. For example, potassium channels use functional groups and angstrom‐sized pores to discriminate rival ions and enrich target ions. Inspired by this, we constructed a layered crystal pillared by crown ether that incorporates these strategies to realize high Li+ selectivity. The pillared channels and crown ether have an angstrom‐scale size. The crown ether specifically allows the low‐barrier transport of Li+. The channels attract and enrich Li+ ions by up to orders of magnitude. As a result, our material sieves Li+ out of various common ions such as Na+, K+, Ca2+, Mg2+ and Al3+. Moreover, by spontaneously enriching Li+ ions, it realizes an effective Li+/Na+ selectivity of 1422 in artificial seawater where the Li+ concentration is merely 25 μM. We expect this work to spark technologies for the extraction of lithium and other dilute metal ions.

Lithium recovery from geothermal brines: An investigation into radioactive nuclide uptake on lithium‑manganese-oxide (LMO) granules

Due to the growing demand for lithium, the exploitation of non-conventional lithium sources such as Li-bearing geothermal brines is currently on the rise. These brines contain up to 200 mg L−1 of lithium along with a diverse range of other dissolved elements, including naturally occurring radionuclides. In this study, data from a radiochemical monitoring process performed during the pilot plant testing of direct lithium extraction (DLE) at a geothermal site in the Upper Rhine Graben (URG) are presented. The tests were conducted under thermodynamic p-T conditions of the geothermal plant (T = 60 °C, p = 18 bar). The results present an uptake of the long-lived radionuclides 226Ra (228Ra) and 210Pb by the granulated lithium‑manganese-oxides (LMO) sorbent employed. Elevated pH values enhance the sorption of nuclides formed in the Th-U decay series, due to the increased negative charge on the LMO surface. The radioactivity uptake on the sorbent was found to be time-dependent. Experiments with a 5-min contact time resulted in relatively low sorption capacities, while extending the sorption time to 30 min significantly increased the accumulation of Ra isotopes and 210Pb on the sorbent surface. During the regeneration phase, the radioactive load on the LMO sorbent could be reduced using 0.5 M HCl. The mass balance analysis of the investigated radionuclides demonstrates desorption percentages ranging from 16% to 100% per extraction cycle.

International solidarity for a de-colonised Just Transition: electric vehicles and lithium in Mexico and Europe

ABSTRACT The term ‘Just Transition’ (JT) gained global prominence through the Silesia Declaration on Solidarity and Just Transition agreed at the 2018 UN Climate Change Conference (COP24). However, there has been a gap in both theory and practice regarding how to develop the global solidarity called for in this declaration. Some have even viewed JT as another form of neo-colonialism, benefitting the Global North through exploiting the Global South. This paper discusses how to avoid perpetuating colonial dynamics through JT by developing worker-led civil society solidarity across the Global North and South. It focusses on Mexico where vast increases in lithium extraction will be necessary to enable the enormous increase in the use of Electric Vehicles proposed for the Global North. While the main beneficiaries of this technology transition will be the companies, governments and consumers of the Global North, the costs will be borne by low-income communities in Mexico, among other Global South localities. Strategies are suggested for a de-colonised JT led by the relevant unions, including car workers.

Lithium recovery from brine by PEG-modified porous LiFePO4/FePO4 electrode system

Lithium recovery from high Mg/Li brine through the electrochemical intercalation /de-intercalation technology has attracted great attention due to its good selectivity. To obtain higher equipment capacity, the LiFePO4/FePO4 electrodes with higher coating density are applied for lithium extraction. Unfortunately, it also brings a problem of slow diffusion of Li+ within the electrode, which limits the intercalation rate of lithium. To solve the problem of Li+ diffusion, a PEG-modified porous LiFePO4 electrode was prepared for lithium recovery. After modification, a “microcracks-microporosity” composite structure appears on the electrode, and the agglomeration of electrode materials reduces due to the dispersing effect of PEG. Therefore, the diffusion resistance of Li+ within the electrode decreases, and the electrode polarization reduces. Using the PEG-modified porous LiFePO4/FePO4 system to recover lithium, the Li+ intercalation rate reaches 4.45 g(Li)·m−2·h−1, while that of unmodified electrode is only 2.10 g(Li)·m−2·h−1. Besides, the intercalation of Na+ was significantly reduced from 0.28 to 0.07 of Na/Fe ratio in FePO4 cathode, which means better selectivity and circularity. Therefore, the application of PEG-modified porous electrode systems can efficiently recover lithium from brines.

Recycling of Valuable Metals from the Priority Lithium Extraction Residue Obtained through Hydrogen Reduction of Spent Lithium Batteries

The selective separation of lithium from spent ternary positive materials is achieved through hydrogen reduction followed by water leaching. Almost 98% of the Li is transformed into soluble LiOH⋅H2O, while the Ni, Co and Mn species are all transformed into insoluble metals or their oxides, so the recovery of Ni, Co and Mn at this stage is challenging. The traditional acid leaching process has drawbacks such as high oxidant consumption, the low recovery of valuable metals and high production costs. Thus, sulfation roasting followed by water leaching was studied in this project. The leaching levels of Ni, Co, Mn and Al reached 87.13%, 99.87%, 96.21% and 94.95%, respectively, with 1.4 times the theoretical amount of sulfuric acid used at 180 °C for 120 min. To avoid the adverse effects of Mn and Al on the quality of the Ni and Co sulfate products, Mn2+ was first separated and precipitated via the KMnO4 oxidation–precipitation method, and >98% of the Mn was removed and precipitated within 30 min with a Kp/Kt (ratio of actual usage to theoretical usage of KMnO4) of 1.0 at pH = 2.0 and 25 °C. After removal of the Mn, the solvent extraction method was adopted by using P204 as an extractant to separate Al. More than 98% of the Al was extracted in 30 min with 20% (v/v) P204 + 10% (v/v) TBP with an A/O ratio of 1:1 at 30 °C. This optimized process for extracting lithium residues improved the hydrogen reduction process of waste lithium batteries and will enable industrialization of the developed processes.

Selective and efficient extraction of lithium from spodumene via nitric acid pressure leaching

The thriving electric vehicle market has fueled a remarkable surge in the demand for lithium. Consequently, a heightened emphasis has emerged on the extraction of lithium from spodumene deposits. However, the sustainable growth of the lithium industry encounters challenges. The traditional process has the disadvantages of high acid consumption, high extraction rate of impurities and difficult purification of leach liquor. To address these challenges, this study proposes a process for the selective and efficient extraction of lithium from spodumene via nitric acid pressure leaching. In an autoclave at 200 °C, initial nitric acid concentration of 1 mol/L, liquid-to-solid ratio of 2.5 mL/g, and holding time of 30 min, 95 % Li was extracted, with low extraction rate of impurity elements. During pressure leaching, the aluminum–silicate cage structure of β-spodumene remains intact, while H+ freely exchanges with Li+ within the structure, resulting in the formation of HAlSi2O6. Subsequently, the leach liquor underwent thermal decomposition at 250 °C to achieve lithium-aluminum separation. It's noteworthy that nitric acid can be recycled in the process, resulting in low acid consumption. The proposed process has the potential to contribute significantly to the lithium industry by facilitating the adoption of environmentally friendly and sustainable practices.

Livent invests in direct lithium extraction

Livent invests in direct lithium extraction

Extraction of Lithium and Synthesis of Kaolinite from α‐Spodumene via Alkali Calcination

AbstractExtracting lithium from spodumene by sulfuric acid roasting is the largest commercialized way at present, which not only consumes a large amount of energy but also produces massive waste residue that will cause environmental problems. In this work, a new process for extracting lithium by directly decomposing α‐spodumene through alkali calcination is designed. The reaction of α‐spodumene with Na2CO3 at 750 °C for 2 h can decompose it and form nepheline and lithium silicate/sodium silicate. The nepheline and soluble lithium silicate/sodium silicate are separated by water leaching, and 93.9 % of lithium can be leached under optimal conditions. In addition, the synthesis of nano‐kaolinite is investigated with nitric acid solutions. Conversions of 98.7 % were obtained with 0.4 M nitric acid at 250 °C and an L/S ratio of 17.5 L/kg. The water leachate can precipitate Li2CO3 with a purity of 99.0 % by CO2 after desilicated by CaO. The final yields of Li2CO3 and kaolinite relative to the Li and Si content of the starting minerals are 91.4 % and 48.5 %, respectively. This new method achieves the full utilization of spodumene with lower energy consumption and demonstrates great potential for industrial applications.

A novel approach for extracting lithium from overhaul slag by low temperature roasting – water leaching

Overhaul slag, as one of the hazardous wastes generated in the aluminum industry, which can pollute the environment and waste resources when arbitrarily stockpiled or landfilled. Scientific and standardized recycling of overhaul slag with both valuable and pollutant characteristics can avoid environmental pollution, and greatly alleviate the global resource shortage crisis. In this paper, an innovative process of sulfuric acid roasting and water leaching is proposed, which can efficiently and environmentally recover F, Al and Li from overhaul slag. The effects of roasting parameters including H2SO4 dosage, roasting temperature and time were systematically investigated. The optimal conditions have been established as: m(H2SO4)/m(overhaul slag) of 1.4:1, roasting temperature of 360 ℃, and time of 2.0 h. Under this conditions, the lithium was converted to NaLi(SO4) and the aluminum was converted to NaAl(SO4)2, during which the HF volatilization rate reached 99.4 %. The roasted clinker was then subjected to water leaching for the extraction of lithium and aluminum. About 99.5 % of lithium and 72.57 % of aluminum was extracted by the leaching process under the optimal conditions. After the leaching solution was treated by pH adjustment, roasting and water leaching, lithium and aluminum could be effectively separated, and the leaching rates of lithium and aluminum were 99.34 % and 0.12 %, respectively. The process proposed in this paper is not limited to the treatment of overhaul slag, but can also be applied to the processing of other aluminum industrial wastes and has a wide application potential.

Solar-driven membrane separation for direct lithium extraction from artificial salt-lake brine

The demand for lithium extraction from salt-lake brines is increasing to address the lithium supply shortage. Nanofiltration separation technology with high Mg2+/Li+ separation efficiency has shown great potential for lithium extraction. However, it usually requires diluting the brine with a large quantity of freshwater and only yields Li+-enriched solution. Inspired by the process of selective ion uptake and salt secretion in mangroves, we report here the direct extraction of lithium from salt-lake brines by utilizing the synergistic effect of ion separation membrane and solar-driven evaporator. The ion separation membrane-based solar evaporator is a multilayer structure consisting of an upper photothermal layer to evaporate water, a hydrophilic porous membrane in the middle to generate capillary pressure as the driving force for water transport, and an ultrathin ion separation membrane at the bottom to allow Li+ to pass through and block other multivalent ions. This process exhibits excellent lithium extraction capability. When treating artificial salt-lake brine with salt concentration as high as 348.4 g L−1, the Mg2+/Li+ ratio is reduced by 66 times (from 19.8 to 0.3). This research combines ion separation with solar-driven evaporation to directly obtain LiCl powder, providing an efficient and sustainable approach for lithium extraction.

Enhancing stability and ionic sieving efficiencies of GO membranes via copper ion crosslinking and tannic acid intercalation

Graphene oxide (GO) membranes have exhibited excellent molecular sieving properties in several areas, such as water treatment and gas separation, but unsatisfactory permeability and/or selectivity for ionic separation. Meanwhile, the instability of pure GO membranes in acidic solution has significantly impeded the ionic sieving applications. In this study, a kind of GO composite membranes (GO-Cu-TAa) with exceptional aqueous stability and superior ionic sieving properties are successfully prepared by employing a unique natural deposition strategy to introduce copper ions and tannic acid (TA). Based on the synergistic effect of the two cross-linking agents of copper ion and TA, the structural stability and ionic sieving performance of GO-Cu-TAa membranes are obviously enhanced. The resultant membrane with 20% TA loading displays excellent ionic sieving performance in a mixed solution containing K+, Mg2+ and Cr3+ three metal cations, and the selectivities of K+/Mg2+ and K+/Cr3+ are 46.43 and 185.32, respectively. Especially, the permeation rate of K+ ion reaches up to 0.75 mol m-2 h-1. Meanwhile, the ionic sieving property of such GO membranes possesses outstanding reusability and long-term stability. Such a membrane can also effectively separate mono-/multivalent metal cations from the mixed solution contained of the nine metal cations. The selectivities of monovalent/divalent metal cations (such as K+/Pb2+, K+/Ca2+, K+/Mg2+) are as high as 7.69–51.49, and those of monovalent/trivalent metal cations (such as K+/Fe3+, K+/Cr3+, K+/Al3+) are as high as 247.62–346.67. These results indicate that the GO-Cu-TAa membranes fabricated by the method of natural deposition strategy are expected to be used in the practical applications of lithium extraction from Salt Lake and wastewater purification, etc.