System and method for recycling lithium from battery waste

Abstract

Embodiments herein relate to recycling of used lithium battery materials. In some aspects, a method may include suspending a lithium source in a solvent containing an oxidizing agent to extract lithium, forming an extracted lithium solution, separating the extracted lithium solution from residual solids of the lithium source, purifying the extracted lithium solution by precipitating and filtering impurities, and precipitating lithium in the purified lithium solution to produce lithium carbonate (Li2CO3). In some embodiments, the method may also include pre-treating the lithium source to improve the kinetics of the lithium extraction. In some embodiments, the pretreatment may include a cutting or comminution step to reduce the size of the lithium source. In some embodiments, the lithium source may include lithium ion battery waste. In some embodiments, the oxidizing agent may include sodium persulfate (Na2S2O8), potassium persulfate ((NH4) 2S2O8), ammonium persulfate (NH4) 2S2O8, hydrogen peroxide (H2O2), ozone (O3), and / or nitrous oxide (N2O).

Description

[0001] Related applications

[0002] This application claims priority and benefit to U.S. Provisional Application No. 63 / 488,378, filed March 3, 2023, entitled "Systems and Methods for the Recycling of Lithium from Battery Waste," and U.S. Provisional Application No. 63 / 469,950, filed May 31, 2023, entitled "Systems and Methods for the Recycling of Lithium from Battery Waste," the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The implementation scheme described herein relates to systems and methods for recycling lithium from spent battery materials. Background Technology

[0004] Lithium-ion batteries (LIBs) are widely used in portable electronic devices, electric vehicles, and grid energy storage due to their low self-discharge rate, high energy and power density, and long cycle life. The LIB market is expected to continue growing in the future. Among cathode active materials, olivine-type lithium iron phosphate (LiFePO4, also known as LFP) and its derivatives have attracted considerable attention and possess several distinct advantages over their counterparts. When LFP and its derivatives are used as cathode materials in LIBs, they are inherently safer, cheaper, and highly durable compared to other cathode materials. However, the LIB production process results in the formation of undesirable byproducts. Capturing and utilizing these byproducts can significantly improve the efficiency of the entire LIB production process. Summary of the Invention

[0005] The embodiments described herein relate to the recycling of used lithium battery materials. In some aspects, a method may include suspending a lithium source in a solvent containing an oxidizing agent to extract lithium, forming an extracted lithium solution, separating the extracted lithium solution from residual solids of the lithium source, purifying the extracted lithium solution by precipitation and filtration of impurities, and precipitating lithium in the purified lithium solution to generate lithium carbonate (Li₂CO₃). In some embodiments, the method may further include pretreating the lithium source to improve the kinetics of lithium extraction. In some embodiments, pretreatment may include a cutting or pulverizing step to reduce the size of the lithium source. In some embodiments, the lithium source may include lithium-ion battery waste. In some embodiments, the oxidizing agent may include sodium persulfate (Na₂S₂O₈), potassium persulfate ((NH₄)₂S₂O₈), ammonium persulfate (NH₄)₂S₂O₈, hydrogen peroxide (H₂O₂), ozone (O₃), and / or nitrous oxide (N₂O). Attached Figure Description

[0006] Figure 1 This is a flowchart of a method for producing Li2CO3 from a lithium source according to an implementation plan.

[0007] Figure 2 This is a flowchart of a method for processing and extracting lithium solution according to an implementation plan.

[0008] Figure 3 This is a flowchart of a method for treating lithium-containing wastewater according to an implementation plan.

[0009] Figure 4 The X-ray diffraction (XRD) pattern of lithium carbonate generated by the embodiment is shown compared with the standard lithium carbonate XRD pattern.

[0010] Figure 5 The XRD pattern of ferric phosphate with extracted Li generated by the embodiment is shown compared with the standard ferric phosphate XRD pattern.

[0011] Figure 6 The XRD pattern of lithium phosphate generated by the embodiment is shown compared with the standard lithium phosphate XRD pattern. Detailed Implementation Plan

[0012] This document describes systems and methods for recycling used batteries. Abundant lithium sources are important for the continued production of new battery materials, including cathode compounds. Global demand for lithium has increased in recent decades. Industries driving this growth include the battery materials industry, the ceramics industry, and the chemical additives industry. High-purity Li₂CO₃ is the most widely used lithium precursor for producing various lithium-ion battery cathode materials. Lithium hydroxide (LiOH) is also a common lithium precursor. Extracting lithium as Li₂CO₃ or LiOH is an effective and economical way to recycle low-cost LFPs and their derivatives, which can include end-of-life, used, discarded, defective LFP batteries, constituent materials, or work-in-process materials.

[0013] The embodiments described herein can develop high-purity Li₂CO₃ products. Methods for producing high-purity Li₂CO₃ include suspending a lithium source and extracting lithium from the suspended lithium source. Precipitation and filtration can be used to improve the purity of the captured Li₂CO₃. In some embodiments, the lithium source material may be derived from electrodes (also called lithium source electrodes), electrode materials, and / or waste electrode materials. In some embodiments, the lithium source may include at least one chemical composition and / or chemical structure comprising lithium. In some embodiments, the lithium source may be included in a mixture or attached to other materials that do not contain lithium. In some embodiments, the lithium source may include components in a system (e.g., full-cell cells, half-cell cells, battery manufacturing waste, battery manufacturing work-in-process materials). In some embodiments, the components may be crushed, cut, milled, or ground into powder or flakes (e.g., black lumps).

[0014] As used herein, the singular forms “a,” “an,” and “the (described)” include plural indicators unless the context clearly indicates otherwise. Thus, for example, the term “a component” is intended to mean a single component or a combination of components, and “a material” is intended to mean one or more materials or a combination thereof.

[0015] When used in conjunction with "cylindrical," "linear," and / or other geometric relationships, the term "substantially" is intended to express that a structure as defined is nominally cylindrical, linear, etc. As an example, a portion of a support member described as "substantially linear" is intended to express that, although linearity is expected, some non-linearity may occur within the "substantially linear" portion. This non-linearity can be caused by manufacturing tolerances or other practical considerations (e.g., pressure or force applied to the support member). Therefore, a geometry modified by the term "substantially" includes such geometric characteristics within a tolerance of ±5% of said geometry. For example, a "substantially linear" portion is a portion defined as an axis or centerline within ±5% of the linearity.

[0016] As used herein, the terms “group” and “multiple” can refer to multiple features or a single feature having multiple parts. For example, when referring to a group of electrodes, the group of electrodes can be considered as a single electrode having multiple parts, or the group of electrodes can be considered as multiple different electrodes. Similarly, for example, when referring to multiple electrochemical units (cells), the multiple electrochemical units can be considered as multiple different electrochemical units or a single electrochemical unit having multiple parts. Thus, a group of parts or multiple parts can include multiple parts that are continuous or discontinuous with each other. Multiple particles or multiple materials can also be manufactured from multiple articles that are produced separately and subsequently joined together (e.g., via mixing, adhesives, or any suitable method).

[0017] Figure 1 This is a flowchart of a method 10 for producing Li₂CO₃ according to one embodiment. Optional steps are shown in dashed boxes. As shown, method 10 optionally includes a step 11 pretreating the lithium source to improve the kinetics of lithium extraction. Method 10 further includes a step 12 suspending the lithium source in a solvent containing an oxidizing agent to extract lithium and form an extracted lithium solution. Method 10 optionally includes a step 13 treating the lithium-extracted material. Method 10 further includes a step 14 separating the extracted lithium from the residual solids of the lithium source, a step 15 purifying the extracted lithium solution by precipitation and filtration of impurities, and a step 16 precipitating lithium in the purified lithium solution to generate Li₂CO₃. Method 10 optionally includes a step 17 separating lithium-containing wastewater, a step 18 adding one or more reagents to the lithium-containing wastewater, and a step 19 further treating the lithium-containing wastewater.

[0018] Step 11 is optional and includes pretreatment of the lithium source to improve the kinetics of lithium extraction. In some embodiments, pretreatment may include mechanical, chemical, and / or thermal treatment of the lithium source. Pretreatment steps can enable or improve the oxidative extraction of the lithium source. Higher reaction kinetics result in higher oxidation reaction rates, thus leading to faster lithium production rates. In some embodiments, pretreatment may alter the properties of the lithium source to enhance ease of lithium extraction. In some embodiments, pretreatment of the lithium source may include crushing, pulverizing, and / or grinding the lithium source. In some embodiments, the lithium source material (e.g., a battery) undergoes a cutting / crushing step to expose the internal cathode material for oxidation and extraction in step 12. In some embodiments, the lithium source material may be reduced in size to flakes or sheets via methods such as crushing, cutting, grinding, or grinding. In some embodiments, the lithium source material may undergo a fine-grinding process to reduce its size to the micrometer / nanometer scale. In some embodiments, the fine-grinding process may include tamping milling, toothed milling, knife milling, ball milling, jet milling, mortar milling, and crushing.

[0019] In some embodiments, pretreatment can improve the wettability of the lithium source material prior to the oxidative extraction in step 12. In some embodiments, the lithium source material can be vacuum-filled to enhance wettability. In some embodiments, the lithium source material can be ultrasonically treated in water prior to and / or during the oxidative extraction in step 12. In some embodiments, the lithium source material can be heated in water to a temperature not exceeding about 100°C, not exceeding about 90°C, not exceeding about 80°C, not exceeding about 70°C, not exceeding about 60°C, not exceeding about 50°C, or not exceeding about 40°C prior to and / or during the oxidative extraction in step 12. In some embodiments, during the pretreatment in step 11, the lithium source material can be heated in air or other gas mixtures (e.g., N2, Ar) to a temperature not exceeding about 800°C, not exceeding about 700°C, not exceeding about 600°C, not exceeding about 500°C, not exceeding about 400°C, not exceeding about 300°C, not exceeding about 200°C, or not exceeding about 100°C. This heating can be used to remove certain components, such as binders or organic matter, from the lithium source, which can allow for a more convenient oxidation process (treatment) in step 12.

[0020] Step 12 includes suspending the lithium source in a solvent containing an oxidizing agent to extract lithium, thereby forming an extracted lithium solution. In some embodiments, the lithium source may include a lithium source electrode (i.e., a lithium-containing electrode). In some embodiments, the lithium source may be derived from a used battery. In some embodiments, the lithium source electrode may include LiFePO4. In some embodiments, the lithium source electrode may include Li x M y PO4, where M is at least one transition metal and x and y are integers. In some embodiments, the lithium source electrode may include a doped derivative of lithium iron phosphate (e.g., LiM). x Fe 1-x PO4 or Li1-xM x PO4, where M can be one or more transition metals, and x and y are integers. In some embodiments, the lithium source electrode may include lithium cobalt oxide (LCO), lithium nickel cobalt manganese oxide (NCM or NMC), lithium nickel cobalt aluminum oxide (NCA), and / or lithium manganese oxide (LMO). In some embodiments, the lithium source electrode may include a composite containing any of the aforementioned materials. In some embodiments, the lithium source electrode may be coated with any of the aforementioned materials.

[0021] In some embodiments, the lithium source may include defective, discarded, or end-of-life lithium-ion batteries. In some embodiments, the lithium source may include used or end-of-life electrode sheets. In some embodiments, the lithium source may include electrode waste. In some embodiments, the lithium source may include used, defective, discarded, or end-of-life lithium-ion batteries. In some embodiments, electrode waste material may include cathode, anode, and / or battery in-process slurry. In some embodiments, electrode waste material may include other battery component or in-process materials or mixtures thereof. In some embodiments, the lithium source may include crushed and / or pulverized end-of-life battery materials. In some embodiments, the lithium source may include mixtures of the electrode forms described above.

[0022] Step 12 includes the oxidation and extraction of the lithium source. This may include oxidizing the transition metal in the lithium source via one or more oxidizing agents (via an oxidant). The lithium is then extracted from the suspension as an extracted lithium solution. The extracted lithium solution can be separated from the residual solids of the lithium source. In some embodiments, the oxidant may include Na₂S₂O₈. Na₂S₂O₈ has a standard redox potential of 1.96 V. The high oxidation voltage of Na₂S₂O₈ can result in a shorter extraction time compared to other oxidants. In some embodiments, the oxidant may include K₂S₂O₈, (NH₄)₂S₂O₈, or any combination thereof. In some embodiments, the oxidant may include H₂O₂. Hydrogen peroxide has a standard redox potential of 1.763 V. The use of H₂O₂ can significantly reduce the sodium / potassium concentration solution, which can introduce less sodium impurities into the produced lithium carbonate. Because the concentration of sodium salts is reduced when H₂O₂ is used as an oxidant, lithium can also precipitate with a smaller final volume (i.e., in step 16 described below) (because less liquid is needed to prevent sodium compounds from precipitating). Therefore, by reducing the amount of Li₂CO₃ dissolved in a smaller volume of solution, the yield of Li₂CO₃ can be increased. In some embodiments, the oxidant may include O₃. Ozone (O₃) has a standard redox potential of 2.07 V. In some embodiments, the oxidant may include N₂O gas. N₂O gas has a standard redox potential of 1.77 V. In some embodiments, the oxidant used in the extraction step may include chlorine gas, which has a standard redox potential of 1.396 V. In some embodiments, the oxidant used in the extraction step may include any combination of the above-mentioned oxidants. In some embodiments, multiple oxidants may be used sequentially or at least partially simultaneously.

[0023] In some embodiments, the amount of oxidant used during oxidation may be at least about 0.25, at least about 0.5, at least about 0.6, at least about 0.7, at least about 0.8, at least about 0.9, at least about 1, at least about 1.1, at least about 1.25, at least about 1.5, at least about 1.75, at least about 2, at least about 2.25, at least about 2.5, at least about 2.75, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, or at least about 9 times the stoichiometric amount required to extract all lithium from the lithium source. In some embodiments, the amount of oxidant used during oxidation may be no more than about 10 times, no more than about 9 times, no more than about 8 times, no more than about 7 times, no more than about 6 times, no more than about 5 times, no more than about 4 times, no more than about 3 times, no more than about 2.75 times, no more than about 2.5 times, no more than about 2.25 times, no more than about 2 times, no more than about 1.75 times, no more than about 1.5 times, no more than about 1.25 times, no more than about 1.1 times, no more than about 1 times, no more than about 0.9 times, no more than about 0.8 times, no more than about 0.7 times, no more than about 0.6 times, or no more than about 0.5 times the stoichiometric ratios described above are also possible (e.g., at least about 0.25 and no more than about 10 or at least about 1 and no more than about 5), including all values ​​and ranges therebetween. In some implementations, the amount of oxidant used during oxidation may be about 0.25, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1, about 1.1, about 1.25, about 1.5, about 1.75, about 2, about 2.25, about 2.5, about 2.75, about 3, about 4, about 5, about 6, about 7, about 8, about 9, or about 10 times the stoichiometric amount required to extract all lithium from the lithium source.

[0024] In some embodiments, the oxidant can oxidize water and generate oxygen and free protons in the extracted lithium solution, thereby creating an acidic environment. For example, Na₂S₂O₈ (or K₂S₂O₈ or (NH₄)₂S₂O₈) is used as the oxidant to generate H₂SO₄. Transition metals in the lithium source can gradually dissolve into the lithium solution under acidic conditions. High concentrations of these impurity ions result in more precipitate during purification in step 15 (described below) and lead to slower extraction rates (e.g., slower if a filtration process is used in the step). Additionally, the dissolution of transition metals into the lithium solution can degrade the structure of the lithium-extracted electrode material and may negatively impact its recyclability (e.g., recycled FePO₄ used for extraction from LFP source materials). In some embodiments, a mixture of Na₂S₂O₈ (or K₂S₂O₈ or (NH₄)₂S₂O₈) and H₂O₂ is used for oxidative extraction. The ratio of Na₂S₂O₈ to H₂O₂ can be adjusted to serve different extraction preferences.

[0025] In some implementations, the wt:wt ratio of Na2S2O8 to H2O2 can be at least about 1:10, at least about 1:9, at least about 1:8, at least about 1:7, at least about 1:6, at least about 1:5, at least about 1:4, at least about 1:3, at least about 1:2, at least about 1:1, at least about 2:1, at least about 3:1, at least about 4:1, at least about 5:1, at least about 6:1, at least about 7:1, at least about 8:1, or at least about 9:1. In some implementations, the wt:wt ratio of Na2S2O8 to H2O2 may not exceed about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, or about 1:9. Combinations of the above weight ratios are also possible (e.g., at least about 1:10 and no more than about 10:1 or at least about 1:3 and no more than about 3:1), including all values ​​and ranges therebetween. In some implementations, the wt:wt ratio of Na2S2O8 to H2O2 can be about 1:10, about 1:9, about 1:8, about 1:7, about 1:6, about 1:5, about 1:4, about 1:3, about 1:2, about 1:1, about 2:1, about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, or about 10:1.

[0026] At higher Na₂S₂O₈ to H₂O₂ ratios, extraction can be faster, and the dissolution of transition metals is reduced due to the lower pH. In some embodiments, the pH of the extracted lithium solution can be controlled during the oxidative extraction process to reduce the dissolution of transition metals. In some embodiments, the pH of the extracted lithium solution can be monitored intermittently or continuously during the oxidative extraction. In some embodiments, alkaline and / or acidic reagents can be added to the extracted lithium solution to maintain the pH of the extracted solution at neutral. In some embodiments, the pH of the extracted lithium solution can be controlled between about 2 and about 3, about 3 and about 4, about 4 and about 5, about 5 and about 6, about 6 and about 7, about 7 and about 8, or about 8 and about 9, including all values ​​and ranges therebetween.

[0027] In some embodiments, acetic acid can be used to control the pH of the extracted lithium solution between about 3.8 and about 5.8. In some embodiments, a mixture of two or more substances from citric acid, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, boric acid, acetic acid, sodium dihydrogen phosphate, and disodium hydrogen phosphate can be used as a pH buffer to control the pH of the extracted lithium solution within a wide range of about 3 to about 9 or even wider. In some embodiments, potassium dihydrogen phosphate (KH2PO4) and / or sodium dihydrogen phosphate (NaH2PO4) can be used to control the pH of the extracted lithium solution between about 6.2 and about 8.2. In some embodiments, 25 parts of 0.2 mol / L K2HPO4, which is mixed with 23.6 parts of 0.1 mol / L sodium hydroxide and diluted to 100 parts with water, can be used to control the pH at about 6.8. The kinetics of the oxidation reaction of some LFP derivatives may be slower than that of LFP. In some embodiments, the LFP derivatives may include Mn, Ni, and Co substituents.

[0028] After the oxidative extraction in step 12 is completed, a lithium-extracted material from which lithium has been removed is generated. Step 13 is optional and includes further processing of the lithium-extracted material. In some embodiments, the lithium-extracted material can be a lithium-deficient or delithiated compound, such as Li 1-x FePO4 (for 0 < x ≤ 1) or a similar compound corresponding to the lithium source material. In some embodiments, the lithium-extracted material can be directly recycled as a precursor for producing the original cathode material. In some embodiments, the lithium-extracted material can be washed with water at least once, at least twice, at least three times, or at least four times to remove any soluble lithium and sodium salt impurities from the oxidative extraction in step 12. In some embodiments, battery-grade FePO4 precursor can be recovered from the lithium-extracted material in step 13. In some embodiments, the precursor can be generated by separating FePO4 from other lithium-extracted materials or impurities and heating FePO4 to remove other unwanted impurities (such as binders, carbon, or other organic compounds). In some embodiments, the lithium-extracted material, such as FePO4 or Li 1-x FePO4 can be heated in air or any other gaseous environment or mixture (such as N2, Ar) to a temperature not exceeding about 1,000 °C, not exceeding about 900 °C, not exceeding about 800 °C, not exceeding about 700 °C, not exceeding about 600 °C, not exceeding about 500 °C, not exceeding about 400 °C, not exceeding about 300 °C, not exceeding about 200 °C, or not exceeding about 100 °C, including all values and ranges therebetween.

[0029] In some embodiments, the lithium-extracted material can be combined with new lithium source material (including the material pretreated in step 11) and subjected to oxidative extraction in step 12 to further extract any residual lithium from the source material. In some embodiments, the oxidative extraction in step 12 can be performed a third or additional time to improve the extraction efficiency of method 10. In some embodiments, after the oxidative extraction in step 12, the lithium-extracted material can be rinsed and washed with water or other solvents to collect residual lithium (which may include a lithium solution or a lithium-containing compound) remaining in the porous structure of the lithium-extracted electrode material. In some embodiments, the residual lithium remaining in the porous structure of the lithium-extracted electrode material can be collected by a centrifugal dryer.

[0030] In step 14, the lithium extracted during step 12 is separated from residual solids or impurities of the lithium source. Step 15 includes precipitating and filtering these impurities to form a purified lithium solution. Step 14 can improve the lithium purity of the extracted lithium solution formed in step 12. Residual solids that can be removed during step 14 may include, but are not limited to, Fe, Mn, Ni, Co, Mg, Ca, P, Al, and Cu. In some embodiments, these impurities can be precipitated as solids at a specific pH range and then removed from the extracted lithium solution. In some embodiments, Fe impurities can be removed by adjusting the pH of the extracted lithium solution to a low Fe solubility pH (e.g., about 8). In some embodiments, an oxidizing agent (e.g., hydrogen peroxide, oxygen, nitric acid, and sodium / potassium / ammonium persulfate) can be added to the extracted lithium solution to remove any Fe impurities. 2+ Oxidized to Fe 3+ To better facilitate the precipitation of Fe in the extracted lithium solution. In some embodiments, Cu impurities are removed when the pH of the extracted lithium solution is adjusted to a low Cu solubility pH (e.g., pH about 9). In some embodiments, Co impurities are removed when the pH of the extracted lithium solution is adjusted to a low Co solubility pH (e.g., pH about 10 to 12 or between 10 and 12). In some embodiments, Ni impurities are removed when the pH of the extracted lithium solution is adjusted to a low Ni solubility pH (e.g., pH about 10 or higher). In some embodiments, Zn impurities are removed when the pH of the extracted lithium solution is adjusted to a low Zn solubility pH (e.g., pH about 10). In some embodiments, Al impurities are removed when the pH of the extracted lithium solution is adjusted to a low Al solubility pH (e.g., pH about 6.5). In some embodiments, the techniques described above for separating and removing precipitates from the extracted lithium solution include, but are not limited to, filtration, centrifugation, sedimentation, or decantation, or any combination thereof.

[0031] The solubility of some impurities in the extracted lithium solution may increase with increasing temperature. In some embodiments, the purification step 15 may include increasing the temperature of the environment in which the purification is performed. The solubility of some impurities may decrease with increasing temperature. In some embodiments, the purification step 15 may include increasing the temperature of the environment in which the purification is performed. In some embodiments, more than one impurity may be removed via pH adjustment. In some embodiments, Fe, Cu, Co, Mg, Mn, Ni and / or Zn may be precipitated and removed at pH values ​​of about 9 to about 10, about 10 to about 11, about 11 to about 12, about 12 to about 13, or about 13 to about 14, including all values ​​and ranges therebetween. In some embodiments, Fe, Cu, Co, Mg, Mn, Ni and / or Zn may be precipitated and removed at pH values ​​of at least about 9, at least about 10, at least about 11, at least about 12, or at least about 13. In some embodiments, Fe, Cu, Co, Mg, Mn, Ni, and / or Zn can be precipitated and removed at pH values ​​not exceeding about 14, about 13, about 12, about 11, or about 10. Combinations of the above pH values ​​are also possible (e.g., at least about 9 and not exceeding about 13 or at least about 10 and not exceeding about 12), including all values ​​and ranges therebetween. In some embodiments, Fe, Cu, Co, Mg, Mn, Ni, and / or Zn can be precipitated and removed at pH values ​​of about 9, about 10, about 11, about 12, or about 13.

[0032] In some embodiments, purifying the extracted lithium solution in step 15 may include adding a salt to the extracted lithium solution. In some embodiments, the salt may include Na₂CO₃, K₂CO₃, sodium oxalate, potassium oxalate, oxalic acid, or a combination thereof. In some embodiments, purifying the extracted lithium solution in step 15 may include adjusting the pH of the extracted lithium solution multiple times. In some embodiments, purifying the extracted lithium solution in step 15 may include a first pH adjustment and a second pH adjustment.

[0033] In some embodiments, the first pH adjustment may be to a pH of at least about 5, at least about 5.5, at least about 6, at least about 6.5, at least about 7, at least about 7.5, at least about 8, or at least about 8.5. In some embodiments, the first pH adjustment may be to a pH of no more than about 9, no more than about 8.5, no more than about 8, no more than about 7.5, no more than about 7, no more than about 6.5, no more than about 5, or no more than about 5. Combinations of the above pH values ​​are also possible (e.g., at least about 5 and no more than about 9 or at least about 6 and no more than about 8), including all values ​​and ranges therebetween. In some embodiments, the first pH adjustment may be to a pH of about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, about 8, about 8.5, or about 9.

[0034] In some embodiments, the second pH adjustment may be to a pH of at least about 8, at least about 8.5, at least about 9, at least about 9.5, at least about 10, or at least about 10.5. In some embodiments, the second pH adjustment may be to a pH of no more than about 11, no more than about 10.5, no more than about 10, no more than about 9.5, no more than about 9, or no more than about 8.5. Combinations of the above pH values ​​are also possible (e.g., at least about 8 and no more than about 11 or at least about 8.5 and no more than about 10.5), including all values ​​and ranges therebetween. In some embodiments, the second pH adjustment may be to a pH of about 8, about 8.5, about 9, about 9.5, about 10, about 10.5, or about 11.

[0035] In some embodiments, step 15 may include filtering the extracted lithium solution to remove precipitated impurities. In some embodiments, step 15 may include evaporating at least a portion of the water present in the extracted lithium solution.

[0036] In some embodiments, the extracted lithium solution may be heated to a temperature of at least about 40°C, at least about 50°C, at least about 60°C, at least about 70°C, at least about 80°C, or at least about 90°C to precipitate Fe, Cu, Co, Mg, Mn, Ni, and / or Zn. In some embodiments, the extracted lithium solution may be heated to a temperature not exceeding about 100°C, not exceeding about 90°C, not exceeding about 80°C, not exceeding about 70°C, not exceeding about 60°C, not exceeding about 50°C, not exceeding about 40°C, or not exceeding about 30°C. Combinations of the above temperatures are also possible (e.g., at least about 40°C and not more than about 100°C or at least about 50°C and not more than about 80°C, including all values ​​and ranges therebetween). In some embodiments, the extracted lithium solution may be heated to temperatures of about 40°C, about 50°C, about 60°C, about 70°C, about 80°C, about 90°C, or about 100°C to precipitate Fe, Cu, Co, Mg, Mn, Ni, and / or Zn. In some embodiments, the pH of the extracted lithium solution may be adjusted via CaO, Ca(OH)2, NaOH, KOH, HNO3, HCl, H2SO4, or any combination thereof.

[0037] In some embodiments, phosphorus impurities can be removed from the extracted lithium solution by adding a Ca salt to the solution. In some embodiments, phosphorus can be precipitated as calcium phosphate (e.g., Ca3(PO4)2), which is largely insoluble in water. Phosphorus can then be removed from the extracted lithium solution via filtration or other similar solids removal methods described herein. In some embodiments, CaCl2 and / or CaSO4 can be added to the extracted lithium solution to precipitate phosphate (PO4). 3-In some embodiments, during phosphate precipitation, the extracted lithium solution can be heated to a temperature of at least about 70°C, at least about 75°C, at least about 80°C, at least about 85°C, at least about 90°C, or at least about 95°C. In some embodiments, during phosphate precipitation, the extracted lithium solution can be heated to a temperature not exceeding about 100°C, not exceeding about 95°C, not exceeding about 90°C, not exceeding about 85°C, not exceeding about 80°C, or not exceeding about 75°C. Combinations of the above temperatures are also possible (e.g., at least about 70°C and not exceeding about 100°C, or at least about 75°C and not exceeding about 95°C), including all values ​​and ranges therebetween. In some embodiments, during phosphate precipitation, the extracted lithium solution can be heated to a temperature of about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C, or about 100°C.

[0038] In some embodiments, a Ca salt may be added during step 12. The phosphorus extracted during step 12 reacts with the Ca salt to form a phosphate precipitate. In some embodiments, the phosphate precipitate is separated and removed by filtration, centrifugation, sedimentation, and decantation, or a combination thereof.

[0039] In some embodiments, phosphate precipitation may occur over a period of at least about 1 hour, at least about 2 hours, at least about 3 hours, at least about 4 hours, at least about 5 hours, at least about 6 hours, at least about 7 hours, at least about 8 hours, at least about 9 hours, or at least about 10 hours. In some embodiments, phosphate precipitation may be carried out at a pH of about 8, about 9, about 10, about 11, about 12, about 13, or about 14, including all values ​​and ranges therein. In some embodiments, phosphate precipitation may be removed from the extracted lithium solution by filtration, centrifugation, or sedimentation and decantation, or a combination thereof. In some embodiments, CaCO3 may be added as a pH buffer during step 12. When the aforementioned pH, temperature, and / or time are reached, the calcium ions dissolved in the extracted lithium solution may precipitate phosphate (phosphate ions).

[0040] In some embodiments, calcium can be removed from the extracted lithium solution by adding carbonate. In some embodiments, Na₂CO₃ and / or K₂CO₃ can be added to the extracted lithium solution to precipitate calcium. In some embodiments, the amount of carbonate added is at least about 1.1 times, at least about 1.2 times, at least about 1.3 times, at least about 1.4 times, at least about 1.5 times, at least about 1.6 times, at least about 1.7 times, at least about 1.8 times, at least about 1.9 times, at least about 2.0 times, at least about 2.1 times, at least about 2.2 times, at least about 2.3 times, at least about 2.4 times, at least about 2.5 times, at least about 2.6 times, at least about 2.7 times, at least about 2.8 times, at least about 2.9 times, or at least about 3.0 times the stoichiometry of calcium to ensure efficient and / or effective removal of calcium ions. In some embodiments, excess carbonate does not react to form lithium carbonate beyond the solubility of the extracted lithium solution. In some embodiments, calcium can be removed by adding a hydroxide to the extracted lithium solution. The calcium precipitates as calcium hydroxide and can then be removed from the extracted lithium solution. In some embodiments, NaOH and / or KOH can be added to the extracted lithium solution to precipitate calcium. In some embodiments, the pH of the extracted lithium solution can be maintained at a level of at least about 9, at least about 10, at least about 11, at least about 12, at least about 13, or at least about 14 to effectively remove calcium ions.

[0041] In some embodiments, calcium can be removed from the extracted lithium solution by adding an oxalate source to the extracted lithium solution. In some embodiments, the oxalate source may include sodium oxalate, potassium oxalate, oxalic acid, or a combination thereof. In some embodiments, the amount of oxalate added is at least about 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 times the stoichiometry of calcium to ensure efficient and / or effective removal of calcium ions. In some embodiments, the pH of the extracted lithium solution may be maintained at at least about 9, 10, 11, 12, 13, or 14 to effectively remove calcium ions.

[0042] In some embodiments, calcium and / or magnesium ions in the extracted lithium solution are removed by passing the extracted lithium solution through an ion exchange resin. In some embodiments, the ion exchange resin has an iminodiacetic acid functional group. In some embodiments, the ion exchange resin has an aminophosphonic acid functional group. In some embodiments, the ion exchange resin has phosphonic acid and / or sulfonic acid functional groups. In some embodiments, the ion exchange resin has an aminomethylphosphonic acid functional group. In some embodiments, more than one ion exchange stage is performed.

[0043] In some embodiments, the extracted lithium solution may be partially evaporated to reduce the volume of the extracted lithium solution. In some embodiments, evaporation is performed prior to the Ca removal step. In some embodiments, evaporation is performed at the end of step 15 and before step 16. A smaller solution volume results in less dissolved Li₂CO₃ and increases the Li₂CO₃ yield. In some embodiments, the volume of the purified lithium solution may be adjusted, varied, or otherwise monitored to ensure it is large enough to dissolve all lithium salts at the precipitation temperature. In some embodiments, sodium and / or potassium salts may precipitate at the end of evaporation. In some embodiments, the precipitated sodium and / or potassium salts are removed via filtration, centrifugation, or sedimentation and decantation, or a combination thereof.

[0044] In some embodiments, the lithium-extracted solution may be heated to a temperature of at least about 60°C, at least about 65°C, at least about 70°C, at least about 75°C, at least about 80°C, at least about 85°C, at least about 90°C, or at least about 95°C to induce calcium precipitation. In some embodiments, the lithium-extracted solution may be heated to a temperature not exceeding about 100°C, not exceeding about 95°C, not exceeding about 90°C, not exceeding about 85°C, not exceeding about 80°C, not exceeding about 75°C, not exceeding about 70°C, or not exceeding about 65°C to induce calcium precipitation. Combinations of the above temperature ranges are also possible (e.g., at least about 60°C and not exceeding about 100°C, or at least about 70°C and not exceeding about 90°C), including all values ​​and ranges therebetween. In some embodiments, the lithium-extracted solution may be heated to a temperature of about 60°C, about 65°C, about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C, or about 100°C to induce calcium precipitation.

[0045] In some embodiments, calcium precipitation can occur over a period of at least about 1 hour, at least about 2 hours, at least about 3 hours, at least about 4 hours, at least about 5 hours, at least about 6 hours, at least about 7 hours, at least about 8 hours, at least about 9 hours, or at least about 10 hours, including all values ​​and ranges therebetween. In some embodiments, the lithium-extracted solution can be maintained at a pH of about 7, about 8, about 9, about 10, about 11, about 12, about 13, or about 14, including all values ​​and ranges therebetween.

[0046] In step 16, lithium is precipitated from the purified lithium solution to form a lithium-containing compound. In some embodiments, the lithium-containing compound may include Li₂CO₃. The precipitated lithium-containing compound (e.g., in the form of precipitated Li₂CO₃) is then separated from and removed from the purified lithium solution. In some embodiments, Na₂CO₃ and / or K₂CO₃ may be added to the purified lithium solution to precipitate the lithium-containing compound. In some embodiments, the purified lithium solution may be filtered with the Na₂CO₃ and / or K₂CO₃ solution to remove any insoluble impurities before adding the Na₂CO₃ and / or K₂CO₃ solution to the purified lithium solution. As the temperature of the purified lithium solution increases, the solubility of the Na and / or K salts increases, while the solubility of Li₂CO₃ decreases.

[0047] In some embodiments, the precipitation of lithium carbonate is carried out at a temperature of at least about 70°C, at least about 75°C, at least about 80°C, at least about 85°C, at least about 90°C, or at least about 95°C. In some embodiments, the precipitation of lithium carbonate is carried out at a temperature not exceeding about 95°C, not exceeding about 90°C, not exceeding about 85°C, not exceeding about 80°C, or not exceeding about 75°C. Combinations of the above temperature ranges are also possible (e.g., at least about 70°C and not exceeding about 100°C, or at least about 75°C and not exceeding about 90°C), including all values ​​and ranges therebetween. In some embodiments, the precipitation of lithium carbonate is carried out at a temperature of about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C, or about 100°C.

[0048] In some embodiments, the purified lithium solution may be partially evaporated before or during the precipitation of the lithium-containing compound to reduce the volume of the purified lithium solution. A smaller solution volume results in less dissolved Li₂CO₃ and increases the yield of Li₂CO₃. In some embodiments, the volume of the purified lithium solution may be adjusted, varied, or monitored to ensure it is large enough to dissolve all Na and / or K salts at the precipitation temperature, as evaporating too much purified lithium solution can cause the Na and / or K salts to precipitate along with the lithium carbonate. In some embodiments, carbon dioxide (CO₂) gas may be pumped into the purified lithium solution to precipitate the dissolved lithium-containing compound. CO₂ can react with hydroxide ions in the purified lithium solution to form carbonate ions, which then form Li₂CO₃, which can then precipitate from the purified lithium solution. In some embodiments, the Li₂CO₃ precipitate may be separated and collected via filtration, centrifugation, sedimentation, decantation, or a combination thereof.

[0049] In some embodiments, the particle size of the precipitated lithium carbonate is controlled by adjusting the conditions during the precipitation step. In some embodiments, these conditions include precipitation temperature, solution stirring speed, the manner in which the lithium solution is added to the Na₂CO₃ and / or K₂CO₃ solution or the Na₂CO₃ and / or K₂CO₃ solution is added to the lithium solution, and solution mixing speed. In some embodiments, higher stirring speeds precipitate smaller lithium carbonate particles. Sodium and / or potassium impurities can be encapsulated by the lithium carbonate particles. Smaller lithium carbonate particles reduce Na and / or K impurities. In some embodiments, the Na₂CO₃ and / or K₂CO₃ solution undergoes a purification step to remove impurities. In some embodiments, the impurities include Ca and / or Mg. In some embodiments, the purification step includes adding oxalate and / or passing the purified lithium solution through an ion exchange resin.

[0050] In some embodiments, the purity of the lithium-containing compound precipitated from the purified lithium solution can be increased through further processing. In some embodiments, Na and / or K are the main impurities in the collected lithium-containing compound (e.g., Li₂CO₃). In some embodiments, the lithium-containing compound can be washed with water or any other suitable solvent to dissolve any residual Na and / or K salts in the lithium-containing compound. In some embodiments, the lithium-containing compound may undergo a washing process with water or any other suitable solvent.

[0051] In some embodiments, the washing process can be carried out at temperatures at least about 70°C, at least about 75°C, at least about 80°C, at least about 85°C, at least about 90°C, or at least about 95°C. In some embodiments, the washing process can be carried out at temperatures not exceeding about 95°C, not exceeding about 90°C, not exceeding about 85°C, not exceeding about 80°C, or not exceeding about 75°C. Combinations of the above temperature ranges are also possible (e.g., at least about 70°C and not exceeding about 100°C, or at least about 75°C and not exceeding about 90°C), including all values ​​and ranges therebetween. In some embodiments, the washing process can be carried out at temperatures at temperatures at least about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C, or about 100°C. In some embodiments, the washed lithium-containing compounds can be separated and collected by filtration, centrifugation, or sedimentation and decantation, or any combination thereof. In some embodiments, the washing process can be repeated multiple times to reduce the Na and K concentrations in the lithium-containing compounds.

[0052] In some embodiments, lithium carbonate may undergo size reduction before or between multiple washing processes. In some embodiments, size reduction is achieved via grinding, crushing, pulverizing, or a combination thereof.

[0053] Step 17 is optional and includes separating the lithium-containing wastewater. The lithium-containing wastewater can be further treated via a wastewater recycling subsystem, which is related to... Figure 3 To describe in more detail. The wastewater recycling subsystem can be used to further extract lithium from the wastewater from the precipitate and the purified wastewater from step 16. Wastewater separation and treatment can increase the overall lithium extraction yield of method 10 and reduce waste.

[0054] Step 18 is optional and includes adding one or more reagents to the lithium-containing wastewater. In some embodiments, the reagent may include phosphate. In some embodiments, the reagent may include Na3PO4. In some embodiments, the reagent may include K3PO4. The addition of the reagent may include further precipitates, such as Li3PO4.

[0055] Step 19 is optional and includes further treatment of the lithium-containing wastewater. In some embodiments, further treatment may include filtration to capture precipitates. In some embodiments, step 19 may include separating and further treating the precipitates. In some embodiments, the precipitates may include Li3PO4.

[0056] In some embodiments, method 10 can produce Li₂CO₃ with the following purities: at least about 70 wt%, at least about 75 wt%, at least about 80 wt%, at least about 85 wt%, at least about 90 wt%, at least about 95 wt%, at least about 96 wt%, at least about 97 wt%, at least about 98 wt%, at least about 99 wt%, at least about 99.5 wt%, at least about 99.9 wt%, or at least about 99.99 wt%, including all values ​​and ranges therein. In some embodiments, method 10 can produce battery-grade Li₂CO₃.

[0057] In some embodiments, the produced Li₂CO₃ may include less than about 1% by weight of impurities. In some embodiments, the produced Li₂CO₃ may include less than about 1% by weight of sodium. In some embodiments, the produced Li₂CO₃ may contain less than about 0.9% by weight, less than about 0.8% by weight, less than about 0.7% by weight, less than about 0.6% by weight, less than about 0.5% by weight, less than about 0.4% by weight, less than about 0.3% by weight, less than about 0.2% by weight, less than about 0.1% by weight, less than about 0.09% by weight, less than about 0.08% by weight, less than about 0.07% by weight, less than about 0.06% by weight, less than about 0.05% by weight, less than about 0.04% by weight, less than about 0.03% by weight, less than about 0.02% by weight, or less than about 0.01% by weight of sodium, including all values ​​and ranges therebetween.

[0058] In some embodiments, the produced Li₂CO₃ may include less than about 1% by weight and less than about 0.9% by weight of calcium. In some embodiments, the produced Li₂CO₃ may include less than about 0.8% by weight, less than about 0.7% by weight, less than about 0.6% by weight, less than about 0.5% by weight, less than about 0.4% by weight, less than about 0.3% by weight, less than about 0.2% by weight, less than about 0.1% by weight, less than about 0.09% by weight, less than about 0.08% by weight, less than about 0.07% by weight, less than about 0.06% by weight, less than about 0.05% by weight, less than about 0.04% by weight, less than about 0.03% by weight, less than about 0.02% by weight, or less than about 0.01% by weight of calcium, including all values ​​and ranges therein.

[0059] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of copper. In other embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, less than about 0.09 ppm by weight, and less than about 0.08 ppm by weight. Copper with a weight of ppm less than about 0.07 ppm, less than about 0.06 ppm, less than about 0.05 ppm, less than about 0.04 ppm, less than about 0.03 ppm, less than about 0.02 ppm, or less than about 0.01 ppm, including all values ​​and ranges in between.

[0060] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of iron. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Iron less than about 0.08 ppm by weight, less than about 0.07 ppm by weight, less than about 0.06 ppm by weight, less than about 0.05 ppm by weight, less than about 0.04 ppm by weight, less than about 0.03 ppm by weight. Iron less than about 0.02 ppm by weight, or less than about 0.01 ppm by weight, including all values ​​and ranges in between.

[0061] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of zinc. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Zinc concentrations of less than 0.08 ppm by weight, less than 0.07 ppm by weight, less than 0.06 ppm by weight, less than 0.05 ppm by weight, less than 0.04 ppm by weight, and less than 0.03 ppm by weight. Zinc concentrations of less than 0.02 ppm by weight or less than 0.01 ppm by weight, including all values ​​and ranges in between.

[0062] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of aluminum. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Less than about 0.08 ppm by weight, less than about 0.07 ppm by weight, less than about 0.06 ppm by weight, less than about 0.05 ppm by weight, less than about 0.04 ppm by weight, less than about 0.03 ppm by weight. Less than about 0.02 ppm by weight, or less than about 0.01 ppm by weight, aluminum, including all values ​​and ranges in between.

[0063] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of nickel. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Less than about 0.08 ppm by weight, less than about 0.07 ppm by weight, less than about 0.06 ppm by weight, less than about 0.05 ppm by weight, less than about 0.04 ppm by weight, less than about 0.03 ppm by weight. Less than about 0.02 ppm by weight, or less than about 0.01 ppm by weight, including all values ​​and ranges therein. In some embodiments, method 10 may produce other lithium-containing compounds, such as LiOH, lithium phosphate (Li3PO4), and / or lithium chloride (LiCl).

[0064] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of non-lithium alkali metal. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Less than about 0.08 ppm by weight, less than about 0.07 ppm by weight, less than about 0.06 ppm by weight, less than about 0.05 ppm by weight, less than about 0.04 ppm by weight, less than about 0.03 ppm by weight. Less than about 0.02 ppm by weight, or less than about 0.01 ppm by weight for non-lithium alkali metals, including all values ​​and ranges in between.

[0065] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of alkaline earth metals. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Less than about 0.08 ppm by weight, less than about 0.07 ppm by weight, less than about 0.06 ppm by weight, less than about 0.05 ppm by weight, less than about 0.04 ppm by weight, less than about 0.03 ppm by weight. Less than about 0.02 ppm by weight, or less than about 0.01 ppm by weight of alkaline earth metals, including all values ​​and ranges in between.

[0066] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of transition metals. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Less than about 0.08 ppm by weight, less than about 0.07 ppm by weight, less than about 0.06 ppm by weight, less than about 0.05 ppm by weight, less than about 0.04 ppm by weight, less than about 0.03 ppm by weight. Transition metals less than about 0.02 ppm by weight or less than about 0.01 ppm by weight, including all values ​​and ranges therein.

[0067] In some embodiments, the produced Li₂CO₃ may include less than about 100 ppm by weight of a metalloid. In some embodiments, the produced Li₂CO₃ may include less than about 90 ppm by weight, less than about 80 ppm by weight, less than about 70 ppm by weight, less than about 60 ppm by weight, less than about 50 ppm by weight, less than about 40 ppm by weight, less than about 30 ppm by weight, less than about 20 ppm by weight, less than about 10 ppm by weight, less than about 9 ppm by weight, less than about 8 ppm by weight, less than about 7 ppm by weight, less than about 6 ppm by weight, less than about 5 ppm by weight, less than about 4 ppm by weight, less than about 3 ppm by weight, less than about 2 ppm by weight, less than about 1 ppm by weight, less than about 0.9 ppm by weight, less than about 0.8 ppm by weight, less than about 0.7 ppm by weight, less than about 0.6 ppm by weight, less than about 0.5 ppm by weight, less than about 0.4 ppm by weight, less than about 0.3 ppm by weight, less than about 0.2 ppm by weight, less than about 0.1 ppm by weight, and less than about 0.09 ppm by weight. Less than about 0.08 ppm by weight, less than about 0.07 ppm by weight, less than about 0.06 ppm by weight, less than about 0.05 ppm by weight, less than about 0.04 ppm by weight, less than about 0.03 ppm by weight. Less than about 0.02 ppm by weight, or less than about 0.01 ppm by weight, all values ​​and ranges in between.

[0068] Figure 2 This is a flowchart of a method 110 for processing an extracted lithium solution according to one embodiment. As shown, method 110 includes adding CaCl2 to the extracted lithium solution in step 111, adjusting the pH of the extracted lithium solution to approximately 10 to approximately 12 in step 112, filtering the extracted lithium solution in step 113, adjusting the pH of the extracted lithium solution to approximately 5 to approximately 9 in step 114, filtering the extracted lithium solution in step 115, optionally adding Na2CO3 to the extracted lithium solution in step 116, optionally adjusting the pH of the extracted lithium solution to approximately 8 to approximately 11 in step 117, and optionally filtering the extracted lithium solution in step 118 to form a purified lithium solution.

[0069] Step 111 involves adding CaCl2 to the extracted lithium solution. In some embodiments, the extracted lithium solution may be the same as or substantially similar to the extracted lithium solution formed in step 12, as described above. Figure 1As described. In some embodiments, step 111 may include adding H2O2 to the extracted lithium solution. In some embodiments, when at least about 0.1%, at least about 1%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, or at least about 10% of phosphate from a lithium source (e.g., a lithium source derived from LFP or LFP derivatives) is leached during oxidative extraction (e.g., in step 11), an amount of CaCl2 may be added to react stoichiometrically with all dissolved phosphate in the extracted lithium solution.

[0070] In some embodiments, when at least about 0.1%, at least about 1%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, or at least about 10%m of Fe(II) is leached during oxidative extraction (e.g., in step 11), the amount of H2O2 added during step 111 can stoichiometrically oxidize at least all Fe(II) in the extracted lithium solution to form Fe(III). By adding H2O2, Fe(II) in the solution can be oxidized to Fe(III).

[0071] Step 112 includes adjusting the pH of the extracted lithium solution to a value between approximately 10 and approximately 12. In some embodiments, step 112 includes adjusting the pH of the extracted lithium solution to a value between approximately 9 and approximately 10. In some embodiments, the pH of the extracted lithium solution can be adjusted to a value between approximately 9, approximately 9.5, approximately 10, approximately 10.5, approximately 11, approximately 11.5, or approximately 12, including all values ​​and ranges therein. Adjusting the pH to such a value can precipitate Fe, Cu, Co, Mg, Mn, Ni, and / or Zn ions. In some embodiments, the pH can be adjusted to a value between approximately 10 and approximately 12 by adding NaOH and / or KOH to the extracted lithium solution. In some embodiments, phosphate ions in the extracted lithium solution can be precipitated by adding CaCl2 (e.g., in the form of Ca3(PO4) by adding calcium ions).

[0072] Step 113 includes filtering the extracted lithium solution to remove precipitated impurities. Step 114 includes adjusting the pH of the extracted lithium solution to approximately 9. In some embodiments, the pH of the extracted lithium solution can be approximately 5, approximately 5.5, approximately 6, approximately 6.5, approximately 7, approximately 7.5, approximately 8, approximately 8.5, or approximately 9, including all values ​​and ranges therein. Adjusting the pH to a value between approximately 5 and approximately 9 can help precipitate aluminum impurities. In some embodiments, the pH adjustment in step 114 can be performed by adding acid to the extracted lithium solution. Step 115 includes another repetition of the filtration. The filtration in step 115 can remove aluminum impurities from the extracted lithium solution.

[0073] Step 116 is optional and includes adding Na₂CO₃ to the extracted lithium solution. Na₂CO₃ can facilitate the precipitation of calcium ions from the extracted lithium solution. Step 117 is optional and includes adjusting the pH of the extracted lithium solution to a value between about 8 and about 11. In some embodiments, the pH can be adjusted to a value of about 8, about 8.5, about 9, about 9.5, about 10, about 10.5, or about 11, including all values ​​and ranges therein. In some embodiments, the pH can be adjusted to a value of at least about 8, at least about 8.5, at least about 9, at least about 9.5, at least about 10, or at least about 10.5. In some embodiments, pH adjustment can be facilitated by adding Na₂CO₃. pH adjustment can facilitate the precipitation of calcium ions.

[0074] Step 118 is optional and includes filtering the extracted lithium solution to form a purified lithium solution. In some embodiments, the filtration in steps 113, 115, and / or 118 may include filtration, centrifugation, sedimentation, decantation, or a combination thereof. In some embodiments, the steps of method 110 may be performed in any order or any step may be omitted. In some embodiments, additional purification steps may be added or the purification steps may be repeated to further improve the purity of the purified lithium solution.

[0075] In some embodiments, the pH adjustment in step 114 and the filtration in step 115 can be performed before the pH adjustment step 112 and the filtration step 113. In some embodiments, step 117 can be omitted when the pH adjustment in step 114 and the filtration in step 115 are performed before the pH adjustment in step 112 and the filtration in step 113.

[0076] In some embodiments, method 110 may include the step of partially evaporating the extracted lithium solution. Evaporation ensures that the final volume of the extracted lithium solution is at least an amount sufficient to dissolve all lithium salts in the solution at all temperatures between room temperature and the evaporation temperature. In some embodiments, Na and / or K salts may precipitate after evaporation. In some embodiments, the evaporation step may include removing the precipitate. In some embodiments, the precipitated Na and / or K salts are removed via filtration, centrifugation, sedimentation, and decantation, or a combination thereof. In some embodiments, the evaporation step may occur before step 111. In some embodiments, the evaporation step may occur after step 111 and before step 112. In some embodiments, the evaporation step may occur after step 113 and before step 114. In some embodiments, the evaporation step may occur after step 115 and before step 116. In some embodiments, the evaporation step may occur just before the ion exchange resin treatment described below.

[0077] In some embodiments, step 116 is optional. In some embodiments, steps 112 and 113 occur after steps 114 and 115, and steps 116, 117, and 118 are optional. In some embodiments, method 110 may include the step of passing the extracted lithium solution through an ion exchange resin to remove Ca and / or Mg ions from the extracted lithium solution. In some embodiments, the ion exchange resin treatment removes Al ions from the extracted lithium solution. In some embodiments, the ion exchange resin is in its lithium form. In some embodiments, the ion exchange resin is in other cation forms, including Na and K. In some embodiments, a partial evaporation step is performed prior to the ion exchange resin treatment. In some embodiments, the ion exchange resin treatment occurs after steps 112 and 113. In some embodiments, steps 112 and 113 occur after steps 114 and 115, and the ion exchange resin treatment occurs after steps 112 and 113. In some embodiments, the ion exchange resin treatment occurs after step 118. In some embodiments, the ion exchange resin treatment occurs at the end of method 110.

[0078] Figure 3 This is a flowchart of method 210 for treating lithium-containing wastewater according to an embodiment. As shown, method 210 optionally includes step 211 washing Li2CO3, step 212 adding a reagent to the lithium-containing wastewater, step 213 filtering the lithium-containing wastewater to remove precipitated Li3PO4, step 214 filtering the extracted lithium solution to remove precipitated Li3PO4, step 215 adding Li3PO4 to a CaCl2 solution to form a LiCl solution, step 216 filtering the precipitate, optionally adding LiCl to the extracted lithium solution in step 217, and optionally purifying Li2CO3 in step 218.

[0079] Step 211 is optional and includes washing the Li2CO3. In some embodiments, the Li2CO3 can be precipitated from a lithium source (e.g., method 10, as described above). Figure 1 (Description). In some embodiments, washing can be performed with water. Washing can improve the purity of LiCO2 and dissolve or otherwise remove precipitates. Step 212 includes adding a reagent to the lithium-containing wastewater. In some embodiments, the lithium-containing wastewater can originate from the Li2CO3 production process (e.g., method 10, as referenced above). Figure 1 (Description). In some embodiments, lithium-containing wastewater may include precipitated wastewater (e.g., as referenced above). Figure 1 The wastewater produced in step 16 described herein is purified wastewater (e.g., generated from a washing process for further purification of Li₂CO₃ products). In some embodiments, the precipitated wastewater has undergone a precipitation step but still contains dissolved lithium. In some embodiments, the dissolved lithium may be in the form of Li₂CO₃. In some embodiments, the molar ratio of Na and / or K to Li in the precipitated wastewater may be greater than about 5:1, greater than about 6:1, greater than about 7:1, greater than about 8:1, greater than about 9:1, greater than about 10:1, greater than about 15:1, greater than about 20:1, greater than about 25:1, greater than about 30:1, or greater than about 35:1. In some embodiments, the molar ratio of Na and / or K in the precipitated wastewater may not exceed about 5:1. In some embodiments, the molar ratio of Na and / or K to Li in the precipitated wastewater may be at least about 35:1.

[0080] In some embodiments, the purified wastewater also contains dissolved lithium. In some embodiments, the dissolved lithium may be in the form of Li₂CO₃. In some embodiments, the molar ratio of Na and / or K to Li in the purified wastewater may not exceed about 4:1, about 3:1, about 2:1, about 1:1, about 0.5:1, about 0.1:1, or about 0.1:1. In some embodiments, the molar ratio of Na and / or K to Li in the purified wastewater may be greater than about 4:1. In some embodiments, the lithium-containing wastewater may be recycled to extract Li₂CO₃. This wastewater recycling process may also reduce the total amount of waste from lithium extraction and may increase the total yield of lithium carbonate from lithium extraction.

[0081] In some embodiments, the reagent added in step 212 may include a phosphate. In some embodiments, the reagent added in step 212 may include Na3PO4, potassium phosphate (K3PO4), and / or ammonium phosphate ((NH4)3PO4). In some embodiments, Na3PO4 can precipitate Li from lithium-containing wastewater. In some embodiments, Na3PO4 can react with dissolved lithium and precipitate lithium as Li3PO4. In some embodiments, Li3PO4 can precipitate at pH values ​​greater than about 4, about 5, about 6, about 7, about 8, about 9, or about 10. In some embodiments, Li3PO4 can precipitate at pH values ​​greater than about 11. Li3PO4 can precipitate at temperatures greater than about 50°C, about 60°C, about 70°C, about 80°C, or about 90°C. In some embodiments, the phosphate added to the lithium-containing wastewater may be at least about 1.0 times, at least about 1.5 times, at least about 2.0 times, at least about 2.5 times, or at least about 3.0 times the stoichiometric amount required to precipitate all lithium from the lithium-containing wastewater. In some embodiments, the phosphate is dissolved in water and filtered to remove any insoluble impurities before being added to the lithium-containing wastewater. In some embodiments, the dissolved Li₂CO₃ in the wastewater is first converted to a more soluble lithium salt by adding an acid, such as HCl or H₂SO₄, before the addition of Na₃PO₄. In some embodiments, the dissolved Li₂CO₃ is converted to LiCl by adding HCl. In some embodiments, the dissolved Li₂CO₃ is converted to Li₂SO₄ by adding H₂SO₄.

[0082] Step 213 includes filtering the lithium-containing wastewater to remove precipitated Li3PO4. Step 214 includes filtering the extracted lithium solution to remove precipitated Li3PO4. In some embodiments, the extracted lithium solution may be derived from an oxidative extraction process (e.g., step 12, as referenced above). Figure 1(Description). In some embodiments, the filtration in steps 213 and / or 214 may include filtration, centrifugation, sedimentation, decantation, or any combination thereof to separate Li3PO4. In some embodiments, the collected Li3PO4 may be washed with water to further remove Na and / or K impurities to produce high-purity Li3PO4. In some embodiments, the filtration in steps 213 and / or 214 produces Li3PO4 with the following purities: at least about 95 wt%, at least about 96 wt%, at least about 97 wt%, at least about 98 wt%, at least about 99.5 wt%, at least about 99.6 wt%, at least about 99.7 wt%, at least about 99.8 wt%, or at least about 99.9 wt%, including all values ​​and ranges therebetween. In some embodiments, high-purity Li3PO4 can be directly reused as a precursor for the production of LFP cathode materials or LFP derivative cathode materials. In some embodiments, high-purity Li3PO4 can be directly used in other industries or production processes.

[0083] In step 215, Li3PO4 is added to the CaCl2 solution to convert Li3PO4 into a soluble LiCl solution. Step 216 includes filtering the precipitate. Li3PO4 reacts with CaCl2 to form soluble LiCl and Ca3(PO4)2 precipitate. In some embodiments, the Ca3(PO4)2 precipitate can be separated and removed by filtration, centrifugation, sedimentation, or decantation, or a combination thereof, to obtain a solution containing LiCl. In some embodiments, the solution is heated to a temperature of at least about 70°C, at least about 75°C, at least about 80°C, at least about 85°C, at least about 90°C, or at least about 95°C to convert Li3PO4 into soluble LiCl. In some embodiments, the solution is heated to a temperature not exceeding about 100°C, not exceeding about 95°C, not exceeding about 90°C, not exceeding about 85°C, not exceeding about 80°C, or not exceeding about 75°C to convert Li3PO4 into soluble LiCl. Combinations of the above temperatures are also possible (e.g., at least about 70°C and no more than about 100°C, or at least about 75°C and no more than about 95°C), including all values ​​and ranges therebetween. In some embodiments, the solution is heated to temperatures of about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C, or about 100°C to convert Li3PO4 into soluble LiCl.

[0084] In some embodiments, the formation of soluble LiCl can occur over a time period of at least about 1 hour, at least about 2 hours, at least about 3 hours, at least about 4 hours, at least about 5 hours, at least about 6 hours, at least about 7 hours, at least about 8 hours, at least about 9 hours, or at least about 10 hours, including all values ​​and ranges therebetween. In some embodiments, the formation of soluble LiCl can occur at pH values ​​of about 7, about 8, about 9, about 10, about 11, about 12, about 13, or about 14, including all values ​​and ranges therebetween. In some embodiments, undetectable Na and / or K may be present in the LiCl solution. In some embodiments, the molar ratio of Na and / or K to Li in the LiCl solution may be less than about 1.5:1, less than about 1:1, less than about 0.5:1, less than about 0.4:1, less than about 0.3:1, less than about 0.2:1, less than about 0.1:1, or less than about 0.01:1.

[0085] In some embodiments, the LiCl solution may undergo a calcium impurity removal step to remove residual calcium from the LiCl solution. In some embodiments, calcium can be removed by reacting and precipitating it in solution. In some embodiments, calcium is precipitated by adding at least one carbonate-containing compound to the LiCl solution. Calcium precipitates as CaCO3 and is then removed from the LiCl solution. In some embodiments, Na2CO3 and / or K2CO3 can be added to the LiCl solution to precipitate calcium. In some embodiments, the amount of carbonate added to the LiCl solution may exceed the stoichiometry of calcium to ensure efficient and / or effective removal of calcium ions. In some embodiments, excess carbonate does not react to form Li2CO3 exceeding the solubility of the LiCl solution.

[0086] In some embodiments, calcium can be removed from the LiCl solution by adding a hydroxide. The calcium can then precipitate as Ca(OH)₂ and be removed from the LiCl solution. In some embodiments, NaOH and / or KOH are added to the LiCl solution to precipitate calcium. In some embodiments, the pH of the LiCl solution can be maintained at a level of at least about 10, at least about 10.5, at least about 11, at least about 11.5, at least about 12, at least about 12.5, at least about 13, at least about 13.5, or at least about 14 to efficiently remove calcium ions from the LiCl solution. The LiCl solution can then undergo precipitation and purification to produce high-purity Li₂CO₃. In some embodiments, the low Na and / or K concentration of the LiCl solution allows for greater evaporation or removal of water from the solution during lithium precipitation and can result in higher yields due to the lower amount of Li₂CO₂ dissolved.

[0087] In step 217, the LiCl solution is optionally combined with the extracted lithium solution (e.g., the extracted lithium solution formed in step 11). The combined solution containing LiCl and the extracted lithium solution can be further purified in step 218. Impurity removal may include lithium precipitation and purification to produce lithium carbonate. In some embodiments, the lithium-containing wastewater generated from the combination of the LiCl solution and the extracted lithium solution can be recycled and further treated (e.g., as described above).

[0088] In some embodiments, the LiCl solution can be combined with the lithium-containing wastewater before the reagent is added to the lithium-containing wastewater in step 212. In some embodiments, LiCl can enhance the purification process of Li₂CO₃. In some embodiments, the remaining lithium-containing wastewater can be treated multiple times via method 210. This can allow for the extraction of more lithium from the lithium-containing wastewater. In some embodiments, the purified wastewater described above with respect to step 212 can be recycled separately by evaporating the purified wastewater to precipitate the dissolved Li₂CO₃. In some embodiments, the final volume of evaporation is sufficient to dissolve all sodium salts in the purified wastewater.

[0089] In some embodiments, method 210 can produce Li₂CO₃ with the following overall purities: at least about 70 wt%, at least about 75 wt%, at least about 80 wt%, at least about 85 wt%, at least about 90 wt%, at least about 92 wt%, at least about 95 wt%, at least about 96 wt%, at least about 97 wt%, at least about 98 wt%, or at least about 99 wt%. In some embodiments, method 210 can produce battery-grade Li₂CO₃ with an overall purity of at least about 99.5 wt%. In some embodiments, method 210 can produce enhanced battery-grade Li₂CO₃ with an overall purity of at least about 99.9 wt%. In some embodiments, method 210 can produce excellent battery-grade Li₂CO₃ with an overall purity of at least about 99.99 wt%.

[0090] In some embodiments, the produced Li2CO3 may include no more than about 1% by weight, no more than about 0.9% by weight, no more than about 0.8% by weight, no more than about 0.7% by weight, no more than about 0.6% by weight, no more than about 0.5% by weight, no more than about 0.4% by weight, no more than about 0.3% by weight, no more than about 0.2% by weight, no more than about 0.1% by weight, no more than about 0.09% by weight, no more than about 0.08% by weight, no more than about 0.07% by weight, no more than about 0.06% by weight, no more than about 0.05% by weight, no more than about 0.04% by weight, no more than about 0.03% by weight, no more than about 0.02% by weight, or no more than about 0.01% by weight of sodium.

[0091] In some embodiments, the produced Li2CO3 may include no more than about 1% by weight, no more than about 0.9% by weight, no more than about 0.8% by weight, no more than about 0.7% by weight, no more than about 0.6% by weight, no more than about 0.5% by weight, no more than about 0.4% by weight, no more than about 0.3% by weight, no more than about 0.2% by weight, no more than about 0.1% by weight, no more than about 0.09% by weight, no more than about 0.08% by weight, no more than about 0.07% by weight, no more than about 0.06% by weight, no more than about 0.05% by weight, no more than about 0.04% by weight, no more than about 0.03% by weight, no more than about 0.02% by weight, or no more than about 0.01% by weight of calcium.

[0092] In some implementations, the produced Li2CO3 may include no more than about 100 ppm by weight, no more than about 90 ppm by weight, no more than about 80 ppm by weight, no more than about 70 ppm by weight, no more than about 60 ppm by weight, no more than about 50 ppm by weight, no more than about 40 ppm by weight, no more than about 30 ppm by weight, no more than about 20 ppm by weight, no more than about 10 ppm by weight, no more than about 9 ppm by weight, no more than about 8 ppm by weight, no more than about 7 ppm by weight, no more than about 6 ppm by weight, no more than about 5 ppm by weight, no more than about 4 ppm by weight, no more than about 3 ppm by weight, no more than about 2 ppm by weight, no more than about 1 ppm by weight, no more than about 0.9 ppm by weight, no more than about 0.8 ppm by weight, no more than about 0.7 ppm by weight, no more than about 0.6 ppm by weight, no more than about 0.5 ppm by weight, no more than about 0.4 ppm by weight, no more than about 0.3 ppm by weight, no more than about 0.2 ppm by weight, no more than about 0.1 ppm by weight, no more than about 0.09 ppm by weight, no more than about 0.08 ppm by weight, and no more than about 0.07 ppm by weight. Copper not exceeding about 0.06 ppm by weight, not exceeding about 0.05 ppm by weight, not exceeding about 0.04 ppm by weight, not exceeding about 0.03 ppm by weight, not exceeding about 0.02 ppm by weight, or not exceeding about 0.01 ppm by weight.

[0093] In some implementations, the produced Li2CO3 may include no more than about 100 ppm by weight, no more than about 90 ppm by weight, no more than about 80 ppm by weight, no more than about 70 ppm by weight, no more than about 60 ppm by weight, no more than about 50 ppm by weight, no more than about 40 ppm by weight, no more than about 30 ppm by weight, no more than about 25 ppm by weight, no more than about 20 ppm by weight, no more than about 10 ppm by weight, no more than about 9 ppm by weight, no more than about 8 ppm by weight, no more than about 7 ppm by weight, no more than about 6 ppm by weight, no more than about 5 ppm by weight, no more than about 4 ppm by weight, no more than about 3 ppm by weight, no more than about 2 ppm by weight, and no more than about 1 ppm by weight. Iron in the following amounts: not exceeding about 0.9 ppm by weight, not exceeding about 0.8 ppm by weight, not exceeding about 0.7 ppm by weight, not exceeding about 0.6 ppm by weight, not exceeding about 0.5 ppm by weight, not exceeding about 0.4 ppm by weight, not exceeding about 0.3 ppm by weight, not exceeding about 0.2 ppm by weight, not exceeding about 0.1 ppm by weight, not exceeding about 0.09 ppm by weight, not exceeding about 0.08 ppm by weight, not exceeding about 0.07 ppm by weight, not exceeding about 0.06 ppm by weight, not exceeding about 0.05 ppm by weight, not exceeding about 0.04 ppm by weight, not exceeding about 0.03 ppm by weight, not exceeding about 0.02 ppm by weight, and not exceeding about 0.01 ppm by weight.

[0094] In some implementations, the produced Li2CO3 may include no more than about 100 ppm by weight, no more than about 90 ppm by weight, no more than about 80 ppm by weight, no more than about 70 ppm by weight, no more than about 60 ppm by weight, no more than about 50 ppm by weight, no more than about 40 ppm by weight, no more than about 30 ppm by weight, no more than about 25 ppm by weight, no more than about 20 ppm by weight, no more than about 10 ppm by weight, no more than about 9 ppm by weight, no more than about 8 ppm by weight, no more than about 7 ppm by weight, no more than about 6 ppm by weight, no more than about 5 ppm by weight, no more than about 4 ppm by weight, no more than about 3 ppm by weight, no more than about 2 ppm by weight, no more than about 1 ppm by weight, no more than about 0.9 ppm by weight, no more than about 0.8 ppm by weight, no more than about 0.7 ppm by weight, no more than about 0.6 ppm by weight, no more than about 0.5 ppm by weight, no more than about 0.4 ppm by weight, no more than about 0.3 ppm by weight, no more than about 0.2 ppm by weight, no more than about 0.1 ppm by weight, no more than about 0.09 ppm by weight, and no more than about 0.08 ppm by weight. Zinc not exceeding about 0.07 ppm by weight, not exceeding about 0.06 ppm by weight, not exceeding about 0.05 ppm by weight, not exceeding about 0.04 ppm by weight, not exceeding about 0.03 ppm by weight, not exceeding about 0.02 ppm by weight, or not exceeding about 0.01 ppm by weight.

[0095] In some implementations, the produced Li2CO3 may include no more than about 100 ppm by weight, no more than about 90 ppm by weight, no more than about 80 ppm by weight, no more than about 70 ppm by weight, no more than about 60 ppm by weight, no more than about 50 ppm by weight, no more than about 40 ppm by weight, no more than about 30 ppm by weight, no more than about 25 ppm by weight, no more than about 20 ppm by weight, no more than about 10 ppm by weight, no more than about 9 ppm by weight, no more than about 8 ppm by weight, no more than about 7 ppm by weight, no more than about 6 ppm by weight, no more than about 5 ppm by weight, no more than about 4 ppm by weight, no more than about 3 ppm by weight, no more than about 2 ppm by weight, no more than about 1 ppm by weight, no more than about 0.9 ppm by weight, no more than about 0.8 ppm by weight, no more than about 0.7 ppm by weight, no more than about 0.6 ppm by weight, no more than about 0.5 ppm by weight, no more than about 0.4 ppm by weight, no more than about 0.3 ppm by weight, no more than about 0.2 ppm by weight, no more than about 0.1 ppm by weight, no more than about 0.09 ppm by weight, and no more than about 0.08 ppm by weight. Aluminum not exceeding about 0.07 ppm by weight, not exceeding about 0.06 ppm by weight, not exceeding about 0.05 ppm by weight, not exceeding about 0.04 ppm by weight, not exceeding about 0.03 ppm by weight, not exceeding about 0.02 ppm by weight, or not exceeding about 0.01 ppm by weight.

[0096] In some implementations, the produced Li2CO3 may include no more than about 100 ppm by weight, no more than about 90 ppm by weight, no more than about 80 ppm by weight, no more than about 70 ppm by weight, no more than about 60 ppm by weight, no more than about 50 ppm by weight, no more than about 40 ppm by weight, no more than about 30 ppm by weight, no more than about 25 ppm by weight, no more than about 20 ppm by weight, no more than about 10 ppm by weight, no more than about 9 ppm by weight, no more than about 8 ppm by weight, no more than about 7 ppm by weight, no more than about 6 ppm by weight, no more than about 5 ppm by weight, no more than about 4 ppm by weight, no more than about 3 ppm by weight, no more than about 2 ppm by weight, no more than about 1 ppm by weight, no more than about 0.9 ppm by weight, no more than about 0.8 ppm by weight, no more than about 0.7 ppm by weight, no more than about 0.6 ppm by weight, no more than about 0.5 ppm by weight, no more than about 0.4 ppm by weight, no more than about 0.3 ppm by weight, no more than about 0.2 ppm by weight, no more than about 0.1 ppm by weight, no more than about 0.09 ppm by weight, and no more than about 0.08 ppm by weight. Nickel not exceeding about 0.07 ppm by weight, not exceeding about 0.06 ppm by weight, not exceeding about 0.05 ppm by weight, not exceeding about 0.04 ppm by weight, not exceeding about 0.03 ppm by weight, not exceeding about 0.02 ppm by weight, or not exceeding about 0.01 ppm by weight.

[0097] Example

[0098] Example 1: 1,000 g of LFP waste electrode (consisting of LFP cathode, binder, and carbon) was pretreated by cutting LFP waste electrode into 1.5 cm LFP waste flakes and immersing it in 2.5 L of water to form a mixture. Then, 712 g of Na₂S₂O₈ powder was added to the mixture for an oxidation extraction step. The LFP waste flakes were stirred in the solution for 40 min. An oxidation reaction was observed by raising the temperature of the solution to approximately 70 °C. The extracted lithium solution was separated from the lithium-extracted LFP waste electrode material by filtration and showed a pH of approximately 3.5. Next, the extracted lithium solution underwent an impurity removal process. The pH of the extracted lithium solution was adjusted to approximately 12 by adding NaOH, and the solution turned green due to the presence of Fe(II). After adding another 68 g of Na₂S₂O₈ to the solution to oxidize Fe(II) to Fe(III), a yellow precipitate was observed. The clear and purified lithium solution was collected after filtration. The elemental analysis of the purified lithium solution by inductively coupled plasma mass spectrometry (ICP) (compared to the initial extracted Li solution before purification) is shown in Table 1. The comparison shows that most of the impurities of Al, P, Ca, Mn, and Zn were removed.

[0099] Next, 300 g of Na₂CO₃ was completely dissolved in 1 L of water and filtered. The Na₂CO₃ solution was added to the purified lithium solution to precipitate lithium. The precipitation reaction was carried out at 90-95 °C for 4 h. The collected initial lithium carbonate was subjected to a series of water washes at room temperature to purify the lithium carbonate. ICP elemental analysis of the final lithium carbonate product (Table 2) showed that Li₂CO₃ had a purity of at least 99.20%. Additionally, Figure 4 The X-ray diffraction (XRD) spectrum of the lithium carbonate product shown is well matched with the standard powder XRD spectrum of lithium carbonate.

[0100] The lithium-extracted LFP waste electrode material after oxidation extraction underwent multiple water washes to remove any residual lithium and sodium. Although trace amounts of carbon and binder may still be present in the material, all XRD patterns of FePO4 were detected in the lithium-extracted LFP waste material, such as... Figure 5 As shown in the figure. This result demonstrates that the disclosed oxidative extraction procedure can extract lithium while retaining the olivine structure of FePO4 in the lithium-extracted material. This recovered FePO4 can be further purified for LFP synthesis and / or reused in another application.

[0101] Example 2: In another example, a mixture comprising 7.5 g of LiMn0.8Fe0.2PO4 electrode (composed of LiMn0.8Fe0.2PO4 cathode, binder, carbon, and Al current collector), 30 g of waste LiFePO4 electrode (composed of LiFePO4 cathode, binder, carbon, and Al current collector), and 30 g of black LiFePO4 powder (composed of LiFePO4 cathode, graphite anode, binder, carbon, and a small amount of Al / Cu impurities) was used as a mixed lithium source. The electrode was pulverized into 1.5 cm flakes and mixed with the black powder in 200 ml of water. After sonication for 10 minutes, 30 g of sodium persulfate was added. The solution was heated to approximately 75°C for 3 h, and the clear lithium solution was collected by filtration. Next, 2 mL of 30 wt% H2O2 and 1.1 g of CaCl2·2H2O were added to the solution. The pH of the solution was adjusted to 12, and the solution was heated to >80°C for 1.5 h. The clear solution was collected after filtration. To remove Al, the pH of the solution was adjusted to 7 using HCl. The solution became turbid and was filtered back to a clear solution using 1-micron filter paper. Next, the pH of the solution was adjusted to 11 and 2 g of Na₂CO₃ was added. After mixing for 2 hours and filtering, the purified lithium solution was collected. Then, 13 g of Na₂CO₃ was completely dissolved in 40 mL of water and filtered. The Na₂CO₃ solution was added to the purified lithium solution for lithium precipitation. The precipitation reaction was carried out at 90 °C for 4 hours. The collected initial lithium carbonate underwent a series of water washes at temperatures >80 °C. ICP elemental analysis of the final lithium carbonate product showed that Li₂CO₃ had a purity of at least 99.20%.

[0102] Another embodiment involves recycling lithium from lithium-containing wastewater generated during lithium extraction. The wastewater composition is represented using a solution containing approximately 7.5 g of Li₂CO₃ and 37.5 g of NaCl dissolved in 1,100 ml of water. Hydrochloric acid was added to the solution to convert all dissolved Li₂CO₃ to LiCl, and the pH of the solution was then adjusted to approximately 8. Next, 28 g of Na₃PO₄·12H₂O was added to the solution to react with Li and precipitate Li₃PO₄. The solution was heated to approximately 80°C for 3 hours, and 7.0 g of Li₃PO₄ powder was collected. Figure 6The XRD pattern of the Li3PO4 product shown matches well with the standard powder XRD spectrum of Li3PO4. Next, 5.3 g of Li3PO4 powder and 11 g of CaCl2·2H2O were added to 100 mL of water. The solution was heated to 85 °C and held for 2 h to convert Li3PO4 to LiCl solution, followed by filtration. The collected LiCl solution was then subjected to a Ca removal step. 4 g of Na2CO3 was added to the solution and stirred for 2 h. Filtration was performed to remove the CaCO3 precipitate. Finally, 3.6 g of Na2CO3 was completely dissolved in 20 mL of water and filtered. The Na2CO3 solution was added to the purified LiCl solution for lithium precipitation. The precipitation reaction was carried out at 90 °C for 4 h. The collected initial lithium carbonate underwent a series of water washes at temperatures >80 °C. ICP elemental analysis of the final lithium carbonate product showed that Li2CO3 had a purity of 99.7% (Table 3).

[0103] Another embodiment involves recovering lithium from LFP waste electrode material. Approximately 600g of LFP waste electrode (consisting of LFP cathode, binder, and carbon) was pretreated by cutting it into 1.5 cm LFP waste flakes and immersing it in 1L of water to form a mixture. Then, 475g of Na₂S₂O₈ powder was added to the mixture for an oxidation extraction step. The LFP waste flakes were stirred in the solution for 40 min. The oxidation reaction was observed by raising the temperature of the solution to approximately 70°C. The extracted lithium solution was separated from the lithium-extracted LFP waste electrode material by filtration and showed a pH of approximately 3.5. Next, the extracted lithium solution underwent an impurity removal process. Approximately 15ml of H₂O₂ and 32g of CaCl₂ were added to the extracted lithium solution and stirred for 2 h. The pH of the extracted lithium solution was adjusted to approximately 6.5 by adding NaOH. The lithium solution was filtered to remove precipitates. The pH of the extracted lithium solution was then adjusted to approximately 10 and stirred for 1 h. The lithium solution was filtered to remove precipitates. Na₂CO₃ was added to the solution and stirred for 1 h. The solution was filtered to remove the precipitate, and then partially evaporated. The extracted lithium solution was then passed through an ion exchange resin to further remove Ca ions. The clear and purified lithium solution was collected after filtration. The ICP elemental analysis of the purified lithium solution (compared to the initial extracted Li solution before purification) is shown in Table 4. The comparison shows that most of the Al, P, Ca, Fe, and Zn impurities were removed.

[0104] Next, 169 g of Na₂CO₃ was completely dissolved in 1 L of water and filtered. The Na₂CO₃ solution was added to the purified lithium solution to precipitate lithium. The precipitation reaction was carried out at 90-95 °C for 4 h. The collected initial lithium carbonate was subjected to a series of water washes at 85-95 °C to purify the lithium carbonate. The lithium carbonate was then calcined at 300-400 °C for 2-4 h to remove water content. ICP elemental analysis (Table 5) shows the impurity concentration of the final lithium carbonate product. Li₂CO₃ has a purity of at least 99.50%.

[0105] Table 1. ICP elemental analysis of purified lithium solution

[0106]

[0107] ICP elemental analysis of lithium carbonate products

[0108]

[0109] ICP elemental analysis of lithium carbonate products

[0110]

[0111] Table 4. ICP elemental analysis of purified lithium solution

[0112]

[0113] Table 5. ICP elemental analysis of lithium carbonate products

[0114]

[0115] Various concepts can be embodied as one or more methods, and at least one example of a method has been provided. Actions performed as part of a method can be ordered in any suitable manner. Therefore, embodiments in which actions are performed in an order different from the order shown can be constructed, which may include the simultaneous execution of some actions, even if shown as sequential actions in the illustrative embodiments. In other words, it should be understood that these features may not necessarily be limited to a particular execution order, but can be performed serially, asynchronously, concurrently, in parallel, simultaneously, synchronously, etc., in a manner consistent with this disclosure. Therefore, some of these features may be contradictory, as they cannot coexist in a single embodiment. Similarly, some features may apply to one aspect of the innovation but not to others.

[0116] Furthermore, this disclosure may include other innovations not currently described. The applicant reserves all rights to such innovations, including the right to implement such innovations, file additional applications, continuation applications, partial continuation applications, divisional applications, etc. Therefore, it should be understood that the advantages, embodiments, examples, functions, features, logic, operation, organization, structure, topology, and / or other aspects of this disclosure should not be considered as limitations on the disclosure as defined by the embodiments or on equivalents of the embodiments. Depending on the specific expectations and / or characteristics of individual and / or enterprise users, database configuration and / or relational models, data types, data transmission and / or network frameworks, syntax structures, etc., various embodiments of the technologies disclosed herein can be implemented in a manner with considerable flexibility and customization as described herein.

[0117] All definitions defined and used herein should be understood as control dictionary definitions, definitions in referenced incorporated literature, and / or the general meaning of the terms defined.

[0118] As used herein, in certain embodiments, when preceding a numerical value, the terms “about” or “approximately” indicate a range of values ​​plus or minus 10%. Where a range of values ​​is provided, it should be understood that, unless the context explicitly specifies otherwise, every intermediate value between the upper and lower limits of that range (to one-tenth of the lower limit unit) and any other value or intermediate value within that range is included within this disclosure. The upper and lower limits of these smaller ranges may be included independently within the smaller range, and also within this disclosure, subject to any specific exclusions within the range. Where a range includes one or both of the included limits, the range excluding any one or both of those included limits is also included in this disclosure.

[0119] The phrase “and / or” as used herein in the specification and embodiments should be understood to mean “any one or both” of the elements so combined, i.e., elements that exist together in some cases and separately in others. Multiple elements listed with “and / or” should be interpreted in the same way, i.e., “one or more” of the elements so combined. In addition to the elements specifically identified by the “and / or” clause, other elements may optionally be present, whether related to or unrelated to those specifically identified. Thus, as a non-limiting example, when used in conjunction with open-ended language such as “including,” a reference to “A and / or B” may in one embodiment refer only to A (optionally including elements other than B); in another embodiment, only to B (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements); and so on.

[0120] As used herein in the specification and embodiments, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” should be interpreted as inclusive, i.e., including multiple elements or at least one of the elements in the list, but also including more than one, and optionally including additional unlisted items. Only terms that explicitly indicate the opposite, such as “only one of…” or “exact one of…”, or when used in embodiments, “consisting of…” will refer to including multiple elements or exactly one of the elements in the list. Generally, when preceded by an exclusive term (e.g., “any one,” “one of…,” “only one of…,” or “exact one of…”), the term “or” as used herein should only be interpreted as indicating an exclusive alternative (i.e., “one or another but not both”). When used in embodiments, “consisting substantially of…” should have its ordinary meaning as used in the field of patent law.

[0121] As used herein in the specification and embodiments, the phrase "at least one" relating to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the element list, but does not necessarily include at least one of each element specifically listed in the element list, and does not exclude any combination of elements in the element list. This definition also allows for the optional presence of elements other than those specifically identified in the element list referred to by the phrase "at least one," whether related to or unrelated to those specifically identified elements. Thus, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B," or equivalently, "at least one of A and / or B") in one embodiment may refer to at least one A, optionally including more than one A, without B (and optionally including elements other than B); in another embodiment, it may refer to at least one B, optionally including more than one B, without A (and optionally including elements other than A); in yet another embodiment, it may refer to at least one A, optionally including more than one A, and at least one B, optionally including more than one B (and optionally including other elements); and so on.

[0122] In the embodiments and in the foregoing description, all transitional phrases, such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “consisting of,” etc., should be understood as open-ended, meaning including but not limited to. Only the transitional phrases “consisting of” and “substantially consisting of” should be closed or semi-closed transitional phrases, respectively, as in Section 2111.03 of the U.S. Patent Examination Procedure Manual.

[0123] While specific embodiments of the present disclosure have been outlined above, many alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, the embodiments described herein are intended to be illustrative rather than restrictive. Various changes can be made without departing from the spirit and scope of the present disclosure. Where the methods and steps described above indicate that certain events occur in a certain order, those skilled in the art who benefit from the present disclosure will recognize that the order of certain steps can be modified, and such modifications are variations of the invention. Furthermore, certain steps may be performed simultaneously in parallel processes, and in the order described above, where possible. Embodiments have been specifically shown and described; however, it should be understood that various changes in form and detail are possible.

Claims

1. A method comprising: Lithium is extracted by suspending a lithium source in a solvent containing an oxidizing agent to form an extracted lithium solution. The extracted lithium solution was separated from the residual solids of the lithium source; The extracted lithium solution was purified by precipitation and filtration of impurities; and Lithium is precipitated in a purified lithium solution to form Li2CO3.

2. The method according to claim 1, further comprising: Pretreatment of lithium sources improves lithium extraction kinetics.

3. The method of claim 2, wherein the pretreatment includes a cutting or crushing step to reduce the size of the lithium source.

4. The method according to claim 1, wherein the lithium source includes lithium-ion battery waste.

5. The method according to claim 1, wherein the oxidizing agent comprises at least one of Na2S2O8, (NH4)2S2O8, (NH4)2S2O8, H2O2, O3 or N2O.

6. The method of claim 1, wherein the purified lithium comprises: Add CaCl2 and H2O2 to the extracted lithium solution; The pH of the extracted lithium solution was adjusted to approximately 10 to approximately 12; and The extracted lithium solution is filtered to remove precipitated impurities.

7. The method of claim 6, wherein the pH is adjusted to about 10 to about 12 by adding at least one of NaOH or KOH.

8. The method of claim 6, wherein the purified lithium solution further comprises: The pH of the extracted lithium solution was adjusted to approximately 5 to approximately 9; and The extracted lithium solution is filtered to remove precipitated impurities.

9. The method of claim 8, wherein the purified lithium solution further comprises: Add Na2CO3, K2CO3, sodium oxalate, potassium oxalate, oxalic acid, or a combination thereof to the extracted lithium solution; The pH of the extracted lithium solution was adjusted to approximately 8 to approximately 11; and The extracted lithium solution is filtered to remove precipitated impurities.

10. The method of claim 9, wherein the purified lithium further comprises: Evaporate at least a portion of the water present in the extracted lithium solution.

11. The method of claim 9, further comprising: The extracted lithium solution is passed through an ion exchange resin.

12. The method of claim 11, wherein the ion exchange resin contains an iminodiacetic acid functional group, an aminophosphonic acid functional group, a phosphonic acid and / or sulfonic acid functional group, or an aminomethylphosphonic acid functional group.

13. The method of claim 1, wherein Li2CO3 is generated by adding at least one of Na2CO3 or K2CO3 to a purified lithium solution.

14. The method of claim 1, wherein Li2CO3 is generated by applying carbon dioxide to a purified lithium solution.

15. The method of claim 1, further comprising: Wash Li2CO3 in water.

16. The method of claim 13, further comprising: Lithium is extracted from lithium-containing wastewater generated from lithium precipitation and washing of Li2CO3.

17. The method of claim 16, wherein the extraction of lithium from lithium-containing wastewater to produce Li3PO4 comprises: Add at least one of Na3PO4 or K3PO4 to lithium-containing wastewater; and Filter lithium-containing wastewater to remove precipitated Li3PO4.

18. The method of claim 17, further comprising: Li2CO3 was washed in water to improve the purity of Li3PO4.

19. The method of claim 16, wherein the extraction of lithium from lithium-containing wastewater to produce LiCl comprises: Add Li3PO4 to the CaCl2 solution; and Filter the CaCl2 solution to produce a LiCl solution.

20. The method of claim 19, further comprising: Add at least one of Na₂CO₃, K₂CO₃, NaOH, or KOH to a LiCl solution; and Filter the LiCl solution to increase its concentration.

21. The method of claim 19, further comprising: Lithium is precipitated in LiCl solution to generate additional Li2CO3.

22. The method of claim 21, wherein precipitating lithium in a LiCl solution to generate additional Li2CO3 is carried out by adding at least one of Na2CO3 or K2CO3 to the LiCl solution.

23. The method of claim 21, wherein precipitating lithium in a LiCl solution to generate additional Li2CO3 is carried out by adding carbon dioxide to the LiCl solution.

24. The method of claim 21, further comprising: Additional Li2CO3 was washed in water to further purify it.

25. The method of claim 24, further comprising: Additional lithium can be extracted from the wastewater generated from washing other Li2CO3.

26. The method of claim 19, further comprising: The LiCl solution is fed into the extracted lithium solution to generate more Li2CO3.

27. The method of claim 26, further comprising: Combine the LiCl solution with another lithium source.

28. A method comprising: Add CaCl2 and H2O2 to the extracted lithium solution; The pH of the extracted lithium solution was adjusted to approximately 9 to approximately 12. The lithium solution extracted during the first filtration; The pH of the extracted lithium solution was adjusted to approximately 5 to approximately 9; and The lithium solution extracted by the second filtration.

29. The method of claim 28, further comprising: Add Na2CO3 to the extracted lithium solution.

30. The method of claim 28, further comprising: The pH of the extracted lithium solution was adjusted to approximately 8 to approximately 11.

31. The method of claim 30, further comprising: The lithium solution was filtered a third time to form a purified lithium solution.

32. A method comprising: A reagent was added to lithium-containing wastewater to form Li3PO4 precipitate; Filter lithium-containing wastewater to remove the first amount of Li3PO4 precipitate; The extracted lithium solution was filtered to remove a second amount of Li3PO4 precipitate; The first amount of Li3PO4 precipitate and the second amount of Li3PO4 precipitate were added to the CaCl2 solution to form a LiCl solution; And filter the precipitate from the LiCl solution.

33. The method of claim 32, further comprising: Li₂CO₃ is washed to form an extracted lithium solution.

34. The method of claim 33, further comprising: LiCl was added to the extracted lithium solution.

35. The method of claim 33, further comprising: Purify Li2CO3.

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