Method for removing fluoride from alkaline hydroxide solution

Abstract

A method for extracting fluoride from a high-pH solution containing greater than 0.1 moles per liter of alkali hydroxide and / or alcoholate dissolved in a polar solvent is described. The polar solvent is selected from water, lower alcohols, and mixtures thereof. The method comprises contacting the liquid solution with a) an alkaline earth salt containing a carbonate, oxo, sulfate, or phosphate anion, and a mixture of such anions or a mixture of such anions with a hydroxyl anion, and b) a cation-binding resin loaded with one or more trivalent cations selected from the group consisting of Al, Ga, In, Fe, Cr, Sc, Y, La, and trivalent cations of the lanthanides.

Description

[Technical Field]

[0001] This application claims the benefit of European Patent Application No. 20208982.7, filed on November 20, 2020, the contents of which are incorporated herein by reference in their entirety.

[0002] The project leading to this application is funded by the Bundesministerium fuer Wirtschaft und Energie (DE;FKZ:16BZF101A), and all disclosures in this document are the responsibility of the applicant.

[0003] This disclosure relates to a method for extracting fluoride from a high pH, ​​typically pH 13 or higher, alkaline aqueous solution, characterized by contacting an alkaline solution with a solid-phase adsorbent selected from alkaline earth salts containing carbonate anions, oxo anions, sulfate anions, phosphate anions, or mixtures thereof, or mixtures thereof with hydroxyl anions, and cation-binding resins loaded with one or more trivalent cations. An example of application of this method is the removal of fluoride from a solution of lithium hydroxide that can be obtained from used lithium-ion batteries. [Background technology]

[0004] Removing fluoride from aqueous solutions is often necessary in the treatment of drinking water. Ion exchange is one common method for defluoridating drinking water with a pH near neutral.

[0005] One application of this method is the recovery of high-purity lithium hydroxide from lithium-containing resources that also contain fluoride ions. Such resources may be geological, for example, lepidolite, which is a lithium mineral, or anthropogenic waste lithium-ion batteries containing at least one transition metal selected from nickel, manganese, and cobalt.

[0006] A typical method for lithium extraction from lepidolite is calcining the mineral with limestone. From mineral solutions containing lithium hydroxide and lithium fluoride, most of the lithium fluoride can be removed after concentration and filtration. The resulting filtrate may still contain small amounts of fluoride, determined by solution equilibrium.

[0007] Similar situations can occur in the recycling of lithium-ion batteries or lithium-ion battery materials. In recycling, lithium is extracted as lithium hydroxide and / or lithium carbonate, and the material and liquid stream typically also contain fluoride. International Publication No. WO2020 / 011765 describes such extraction, particularly in its Examples 2-4.

[0008] Fluoride-containing lithium hydroxide solutions may also result from the electrochemical conversion of solutions of lithium salts, such as lithium chloride or lithium sulfate. Such electrochemical conversions, including electrolysis or electrodialysis, are also described in the context of lithium-ion batteries or the recycling of lithium-ion battery materials (WO2014138933, EP2906730).

[0009] The alkaline solutions treated by this disclosure may also arise from lithium-containing materials such as brine, ore, slag, and flue gas ash. The amount of fluoride impurities is typically about 121 ppm or more, e.g., about 300 ppm or more, or about 500 ppm or more, e.g., 1% or more, 0.05–5%, or 1.4–3.2% of ionic fluorides, each relative to the total mass of lithium contained, and dissolved in such liquids. The alkali salts present include hydroxides and alcoholates. In the case of lithium hydroxide, it may exist in a dry form, either anhydrous or as lithium hydroxide monohydrate. The liquid may contain one or more further impurities from the group of other alkali salts, aluminum salts, and / or zinc salts. The total amount of alkali, aluminum, and zinc impurities is approximately 100 to 500 ppm or more, for example, approximately 500 to 10,000 ppm or approximately 500 to 5,000 ppm, relative to the dry mass of the crude alkali hydroxide (or alkole) solid.

[0010] High concentrations of hydroxyl ions are known to displace fluoride from potential binding sites on adsorbents so that they are present at high pH values ​​(P. Loganathan et al., J. Haz. Mat. 248-249 (2013), see, for example, Figure 1 on page 3 and paragraph 3.1 on page 4; Loganathan has also reported numerous adsorbents that are active in the pH range of 12 or less). [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] International public access number WO2020 / 011765 [Patent Document 2] WO2014138933 [Patent Document 3] EP2906730 [Non-patent literature]

[0012] [Non-Patent Document 1] P.Loganathan et al.,J.Haz.Mat.248-249(2013) [Overview of the project] [Means for solving the problem]

[0013] Here, it was found that a certain adsorbent is remarkably effective in removing fluorides from high pH solutions. This disclosure relates to a method for extracting fluorides from a solution containing more than 0.1 moles of alkali hydroxides and / or alkoles per liter dissolved in a polar solvent, wherein the liquid solution is: a) Alkaline earth salts containing carbonate anions, oxo anions, sulfate anions, or phosphate anions, and alkaline earth salts containing mixtures of such anions or mixtures of such anions and hydroxyl anions, b) A cation-bonded resin loaded with one or more trivalent cations selected from trivalent cations of Al, Ga, In, Fe, Cr, Sc, Y, La, and lanthanides. Contact with a more selected solid-phase adsorbent.

[0014] The polar solvent is selected from water, lower alcohols, and mixtures thereof. The lower alcohol is selected from C1-C4 alcohols or mixtures thereof, such as methanol and / or ethanol. The lower alcohol used as a polar solvent or contained in a polar solvent is an industrial product containing about 6% by mass or less of water, the remainder of the product being mainly other alcohols and / or water, and other impurities, such as non-alcoholic organic solvents, may be present in amounts of 1% by mass or less of the lower alcohol product or solvent mixture based on such alcohol. The polar solvent is selected from water, methanol, ethanol, and mixtures thereof. In some embodiments, the polar solvent contains at least 50% by mass of water and / or methanol (each by the mass of the total liquid). In some embodiments, the polar solvent contains 70% by mass or more of water and / or methanol (each by the mass of the total liquid). In some embodiments, the polar solvent contains 80% by mass or more of water and / or methanol (each by the mass of the total liquid). In some embodiments, the polar solvent contains 90% by mass or more of water and / or methanol (each by the mass of the total liquid). In some embodiments, the polar solvent comprises 95% by mass or more of water and / or methanol (each by mass of the total liquid).

[0015] The solid-phase adsorbents are as follows: a) Alkaline earth salts including calcium phosphate, calcium hydroxyphosphate, calcium sulfate, magnesium carbonate, magnesium oxide, calcium hydroxyapatite and / or tricalcium phosphate, and b) A cation-bonded resin loaded with one or more trivalent cations selected from the trivalent cations of aluminum and lanthanum. More likely to be selected.

[0016] In the method of the present disclosure, a calcium phosphate adsorbent is used. Among Ca phosphates, two types show a remarkable improvement in fluoride adsorption at high pH: Ca5(PO4)3OH and Ca hydroxyapatite having a hydroxyapatite crystal structure (P63 / m), and tricalcium phosphate having the formula Ca3(PO4)2 and a beta-tricalcium phosphate structure (R3ch). Both are related materials because Ca-deficient Ca-hydroxyapatite releases one water molecule at high temperature and is converted to a beta-tricalcium phosphate structure (Ca 4.5 (H 0.5 PO4)3OH → 1.5Ca3(PO4)2 + H2O). Therefore, in the material treated at high temperature, usually both materials are mixed.

[0017] Various types are commercially available from both classes of adsorbents (a) and (b). Cation-binding ion exchange resins are based on a cross-linked polystyrene matrix and have binding sites of -COOH type (for example, a functional group consisting of two carboxylic acid groups -COOH, such as a chelating iminodiacetic acid group) or phosphonic acid group (C-PO(OH)2, for example, a chelating aminomethylphosphonic acid group, etc., bonded to a nitrogen atom bonded to the polymer structure of the resin). The loading of cations can be carried out by well-known methods.

[0018] The dissolved alkali hydroxide treated by this method is selected from the hydroxides of lithium, sodium, potassium, cesium, and rubidium. In some embodiments, the alkali hydroxide is lithium hydroxide, and water or methanol or a mixture thereof is used as the polar solvent. In the case of an alkali hydroxide other than lithium hydroxide, the polar solvent mainly contains water. When a lower alcohol is selected as the polar solvent, the dissolved alkali species may contain or consist of alkali alcoholates such as lithium, sodium, potassium, cesium, and / or rubidium, and methanolate. When the polar solvent is a mixture of water and a lower alcohol, the alkali species may be an alkali hydroxide.

[0019] In some embodiments, the method is effective for removing fluoride dissolved from a high pH solution. In some embodiments, this method treats a solution containing a hydroxide and / or alcoholate concentration exceeding 0.1 mol / l. For example, an alkali hydroxide and / or alcoholate solution contacted with the adsorbent (a) or (b) according to the present disclosure may contain, in dissolved state, 0.2 mol or more of alkali hydroxide and / or alcoholate per liter of solution. In some embodiments, this method is used to treat a solution containing 0.35 mol or more of alkali hydroxide and / or alcoholate per liter of solution in dissolved state. In some embodiments, this method is used to treat a solution containing 0.5 mol or more of alkali hydroxide and / or alcoholate per liter of solution in dissolved state. In some embodiments, this method is used to treat a solution containing 0.7 mol or more of alkali hydroxide and / or alcoholate per liter of solution in dissolved state. As an example, dissolved lithium hydroxide or lithium methoxide at a concentration of 0.1 to the solubility limit (the maximum dissolved concentration), for example, 0.1 to 10 mol per liter of solution, for example 0.2 to 8 mol per liter, 0.5 to 6 mol per liter, or 0.7 to 5.3 mol per liter. In some embodiments, the lithium content in such a solution may range from about 0.2 to about 3.7% by mass of the solution.

[0020] The method may be carried out under various pressure conditions, and compression of the adsorbent is to be avoided. In some embodiments, the operating pressure may be selected, for example, from 0.1 bar to 100 bar. For example, the operating pressure of the liquid during contact with the adsorbent may be 0.5 bar to 25 bar, for example 0.5 bar to 5 bar.

[0021] In some embodiments, high temperatures are advantageous for adsorption, while temperature limitations are imposed by polar solvents, which should remain within their liquid range, and, if resin adsorbents (b) are selected, by the operating temperature range of the resin, which is approximately 85°C or less. Thus, typical operating temperatures are higher than the melting temperature of the liquid and below the boiling point of the liquid at the operating pressure, for example, 0°C to 150°C for mineral adsorbents (a) or 0°C to 85°C for resin adsorbents (b). [Brief explanation of the drawing]

[0022] [Figure 1] Figure 1 shows the configuration of the column for fluoride reduction at high pH according to this disclosure. [Figure 2] Figure 2 shows a block flow diagram of a lithium leaching process starting from black lumps (particulate matter, PM) obtained from waste lithium-ion batteries, illustrating the fluoride reduction process of the present invention, exemplified by the F-adsorption step onto apatite. [Figure 3] Figure 3 shows a block flow diagram of another embodiment of a lithium leaching process starting from black lumps (particulate matter, PM) obtained from waste lithium-ion batteries, illustrating the fluoride reduction process of the present invention, exemplified by the F-adsorption step to apatite. [Figure 4] Figure 4 shows the X-ray powder diffraction pattern (Mo Ka) of the reduced aggregate from the waste lithium-ion battery after heating / reduction treatment, obtained in Example 1a and used in Educt Example 2a, as well as the reference diffraction patterns for graphite, cobalt, manganese(II) oxide, cobalt oxide, and nickel. [Figure 5] Figure 5 shows the X-ray powder diffraction (Mo Ka) and reference diffraction patterns of graphite, lithium aluminate, and lithium carbonate of the reduced aggregate from the waste lithium-ion battery after heating / reduction treatment, obtained in Example 1a and used in Educt Example 2a. [Figure 6]Figure 6 shows the X-ray powder diffraction pattern (Cu Ka) of the reduced aggregate from the waste lithium-ion battery after heating / reduction treatment, obtained in Example 1a and used in Educt Example 2a, as well as reference diffraction patterns for graphite, cobalt, manganese(II) oxide, cobalt oxide, and nickel. [Figure 7] Figure 7 shows the X-ray powder diffraction pattern (CuKa) of the reduced aggregate from waste lithium-ion batteries after heating / reduction treatment, obtained in Example 1a and used in Educt Example 2a, as well as reference diffraction patterns for graphite, lithium aluminate, and lithium carbonate. [Figure 8] Figure 8 shows the X-ray powder diffraction pattern (Cu Ka) of the LiOH monohydrate obtained in Educt Example 5. [Modes for carrying out the invention]

[0023] General definition: Unless otherwise specified, "contains" any substance generally means the presence of the substance in an amount typically still detectable by X-ray powder diffraction, e.g., 1% by mass or more, or the presence of the component in an amount typically detectable by ICP after suitable digestion, e.g., 10 ppm by mass or more.

[0024] The term "approximately" indicates a potential deviation of up to 5% in any direction, and especially up to 1%, with respect to any specified quantity.

[0025] Preparation of fluoride-containing LiOH solution from used lithium-ion batteries The alkaline solution processed by this disclosure is a process step as follows: (A) A step of providing a transition metal compound and / or particulate matter (PM) containing a transition metal, wherein the transition metal is selected from Mn, Ni and Co, and further, at least a portion of Ni and / or Co is in an oxidation state lower than +2, e.g., metallic, if present, and at least a portion of Mn is manganese(II) oxide if present, and the particulate matter further contains a lithium salt and a fluoride salt, and (B) A step in which the material provided in step (A) is treated with a polar solvent, such as an alkaline earth hydroxide, to separate the solid from the liquid, and optionally the solid residue is then washed with a polar solvent, such as water. This is obtained by performing the following. The liquid thus obtained may be subsequently processed according to the present disclosure. Details of such steps (A) and (B) are as follows.

[0026] A) Provision of particulate matter (PM; reduced black clumps) Several authors have described the heat treatment of waste lithium-ion batteries or components containing electrode active materials of this type of battery at temperatures above 400°C. As a result of such heat treatment, the electrolyte solvent contained in the battery completely evaporates and the polymer components decompose. The material obtained from such heat treatment can be subjected to different mechanical treatments and separation operations to separate different metal fractions and powdery materials containing electrode active materials mainly from the anode, i.e., graphite, and electrode active materials from the cathode, i.e., lithium-containing transition metal materials. These powders are often referred to as "black lumps," "black powders," or "active lumps." In the following disclosure, these powders are described as particulate matter (PM). Depending on the reaction conditions, the latter material is often at least partially reduced to contain metallic Ni and Co phases, manganese oxide phases, and lithium salts, such as LiOH, Li2CO3, LiF, LiAlO2, and Li3PO4. Reduction is carried out by introducing a reducing gas such as hydrogen or carbon monoxide (e.g., provided in International Publication No. WO2020 / 011765) during heat treatment under reduction conditions, or by introducing carbonaceous materials contained in the waste battery material, namely graphite and soot, at temperatures exceeding 500°C. For example, reference J. Li et al., J. Hazard. Mat. 2016, 302, 97 onwards discloses an oxygen-free roasting / wet magnetic separation process for recycling cobalt, lithium carbonate, and graphite from used LiCoO2 / graphite batteries.

[0027] B) Lithium extraction from particulate matter Furthermore, International Publication WO2020 / 011765 discloses that the above lithium salts, such as LiOH, Li2CO3, LiF, LiAlO2, and Li3PO4, can be extracted by treating the at least partially reduced product with a polar medium, usually an aqueous medium. Alkaline earth hydroxides (AEHs) are used to convert the contained lithium species into lithium hydroxides. The aqueous medium, such as an aqueous solvent or aqueous liquid, mainly contains water (i.e., 50% or more by mass, 80% or more by mass, or 90% or more by mass). It contains water and mixtures of water with one or more alcohols, and may further contain dissolved substances as long as the main water content is maintained within one or more of the above ranges.

[0028] Lithium hydroxide extraction provides a suspension of particulate matter in a polar solvent. This may be carried out by heating. Treatment with alkaline earth hydroxides is carried out at temperatures in the range of about 60°C to about 200°C, or about 70°C to about 150°C. If the temperature exceeds the boiling point of the polar solvent, the treatment is carried out under pressure to keep the solvent or at least a portion of it in a liquid state. The temperature range is around the boiling point of water, i.e., about 70°C to 150°C, and the treatment can be carried out using aqueous liquid or water at atmospheric pressure or a slightly increased pressure (e.g., 5 bar or less). Alternatively, this step (B) can be carried out by applying higher temperatures and pressures, e.g., 150°C to 300°C and 1.5 bar to 100 bar.

[0029] The treatment is carried out by combining an amount of alkaline earth hydroxide with particulate matter, the amount of which corresponds to at least 5% and no more than 100% of the mass of alkaline earth hydroxide, for example, 50 to 1000 g of AEH per 1 kg of PM, e.g., 100 to 1000 g of AEH, or 200 to 1000 g of AEH per 1 kg of PM. The amount of polar solvent is selected to ensure the miscibility of the components, for example, 1 part by mass of the combined solid (PM and AEH), 0.5 to 95 parts by mass of polar solvent, about 2.5 to 21 parts by mass, or in certain cases, 1 to 20 parts by mass of polar solvent, e.g., about 2 to 10 parts by mass.

[0030] In some embodiments of this disclosure, extraction is carried out in a container protected from strong bases, such as a molybdenum and copper-enriched steel alloy, a nickel-based alloy, a duplex stainless steel or glass-lined container, or an enamel or titanium-coated steel container. Further examples are polymer liners and polymer containers made from base-resistant polymers, such as polyethylenes, such as HDPE and UHMPE, fluorinated polyethylene, perfluoroalkoxyalkanes ("PFA"), polytetrafluoroethylene ("PTFE"), PVdF, and FEP. FEP represents copolymers from fluorinated ethylene propylene polymer, tetrafluoroethylene, and hexafluoropropylene.

[0031] The process is carried out using a mixing device, such as a stirrer, applying a power of 10 W or less per kg of suspension, for example, 0.5 to 10 W / kg, and / or circulating by a pump, to achieve good mixing and avoid settling of insoluble components. Shearing can be further improved by using baffles. Furthermore, the slurry obtained in step (B) may be subjected to grinding, for example, in a ball mill or a stirred ball mill. Such grinding provides better access of the polar solvent to the particulate lithium containing the transition metal oxide material. The shearing and grinding devices to be used are typically well corrosion-resistant and may be manufactured from the same materials and coatings as described above for the containers.

[0032] In some embodiments of this disclosure, the extraction has a duration ranging from 20 minutes to 24 hours, for example, 1 to 10 hours.

[0033] In some embodiments, extraction is performed at least twice to achieve an optimal recovery rate of lithium hydroxide or lithium salt. Solid-liquid separation is performed between each treatment. The resulting lithium salt solutions may be combined or treated separately to recover the solid lithium salt.

[0034] In some embodiments of the present disclosure, step (B), which includes extraction and solid-liquid separation, is performed in batch mode.

[0035] In some embodiments of the present disclosure, extraction and solid-liquid separation are performed in a continuous mode, for example, in a cascade of stirring vessels and / or a cascade of stirring vessels and centrifuges.

[0036] In some embodiments of the present disclosure, the polar solvent in step (B) is an aqueous medium, and the ratio of the aqueous medium to the material provided in step (A) is in the range of 1:1 to 99:1 by mass, for example, 5:1 to 20:1.

[0037] Alkaline earth hydroxides are selected from Mg, Ca, Sr, and Ba hydroxides. In some embodiments, alkaline earth hydroxides are selected from calcium hydroxides, barium hydroxides, and mixtures thereof. In some embodiments, the alkaline earth hydroxide is calcium hydroxide. The alkaline earth hydroxide used in step (B) may be used as is, or it may be added in the form of an oxide or a mixture of an oxide and a hydroxide and brought into contact with a polar solvent selected from the above-mentioned protic solvents to form an alkaline earth hydroxide.

[0038] The particulate matter provided in step (A) includes material obtained from lithium-containing transition metal oxide materials such as lithium-ion battery waste after performing a preliminary step (i) in which the material is heated to a temperature in the range of 80°C to 900°C, for example, 200°C to 850°C or 200°C to 800°C, under inert or reducing conditions. Preliminary step (i) is typically performed immediately after the discharge, dismantling, and / or crushing of the lithium-ion battery, as will be described in more detail below. In some applications, crushing and / or dismantling is performed after preliminary step (i). The lithium-ion battery used, and therefore the particulate matter provided in step (a), typically contains carbon, for example, in the form of graphite.

[0039] Where high temperatures are observed (for example, in the processing of materials in step (i) of the present invention), the exposure time, if indicated, defines the total residence time (synonymous with residence time) in a reactor or furnace heated to a high temperature. The temperature of the material should reach a temperature from a given range for at least a portion of the residence time.

[0040] C) LiOH solution from lithium hydroxide leaching By performing the lithium hydroxide leaching described above, a solution containing lithium, typically as LiOH, at the aforementioned concentrations is obtained. Therefore, the pH of this solution is strongly basic, for example, pH 13 or higher.

[0041] This LiOH solution contains several characteristic impurities, such as, but not limited to, fluorine. A typical fluorine load is 500 ppm or more relative to dry LiOH, as further described above. In some embodiments of this disclosure, the fluorine concentration is in the range of 0.05% to 5% by mass, for example, 0.1% to 4% by mass or 0.1% to 2% by mass, respectively, relative to dry LiOH. The removal of this fluorine, described as anionic fluoride, is the subject of this disclosure.

[0042] D) Removal of fluoride using adsorbents The method for removing fluoride is characterized by contacting an alkaline solution with a solid-phase adsorbent selected from the above-mentioned alkaline earth salts and loading resins.

[0043] Adsorption utilizes the tendency of one or more components of a liquid or gas to accumulate on a solid surface. This tendency can be used to remove solutes from a liquid or gas, or to separate components that have different affinities to a solid. This process may be used for waste treatment or the purification of valuable components in a feedstream. In an adsorption process, the solid is called the adsorbent, and the solute is called the adsorbed material.

[0044] It is highly porous, with a pore surface area of ​​approximately 100 m². 2 / g~1,200m2 Commercially available adsorbents in the range of / g are useful. Their large surface area allows for the adsorption of a large amount relative to their mass, sometimes far exceeding their own weight. Furthermore, they can reduce the solute level in the treatment solution to a fraction of ppm.

[0045] The affinity of a fluid component for a particular adsorbent depends on its molecular properties, such as size, shape, polarity, partial pressure or concentration in the fluid, and system temperature (J. Wilcox, Carbon Capture, New York: Springer Science+Business Media, LLC, 2012). The strength of surface forces depends on the properties of both the solid and the adsorbent. When the forces are relatively weak and involve only van der Waals interactions, known as dispersion repulsion, and electrostatic forces arising from polarization, dipole, quadrupole, and high-polarity interactions, it is called physicoadsorption or physioscopy. Van der Waals forces exist in all systems, while electrostatic interactions exist only in systems containing charge, and the surface of the adsorbent is accompanied by functional groups and surface defects. When the interaction forces are strong and involve considerable electron transfer, it is called chemiadsorption. Generally, physicoadsorption occurs when the heat of adsorption is less than about 10-15 kcal / mol, while chemiadsorption occurs when the heat of adsorption is greater than 15 kcal / mol. However, these are general principles, and exceptions exist. Physical adsorption is a non-active, reversible, and rapid process in which polarization is possible, but electron transfer does not occur. Chemisorption is a slower process than physical adsorption due to the electron transfer that leads to bonding between the adsorbent and the surface, and the activation barriers that must be overcome to form the bonded complex.

[0046] Ion exchange is generally defined as a reversible chemical interaction between a solid and a fluid in which selected ions are exchanged between the solid and the fluid. An exemplary ion exchange process involves a fluid passing through a bed of porous resin beads containing charged, mobile cations or anions, such as hydrogen ions or hydroxide ions, which are available for exchange with metal ions or anions present in the fluid. The ion exchange resin readily exchanges hydrogen ions with metal ions, or hydroxide ions with other anions, as the liquid passes through the bed. Over time, the number of hydrogen ions or hydroxide ions available for exchange with metal ions or other anions decreases.

[0047] Eventually, the resin is consumed, and further ion exchange becomes impossible (i.e., all available exchange sites are filled). However, the resin can be regenerated. In the case of cation exchange resins, regeneration is achieved by using a regeneration solution containing an acid, i.e., a large amount of excess hydrogen ions, and passing it over the ion exchange beads to expel the collected ions from the resin, thereby returning the ion exchange resin to its original form. An example of a cation exchange process is the purification / softening of tap water. In this process, a weakly acidic ion exchange resin uses carboxylic acid groups in anionic form (e.g., sodium form) as cation exchange sites. Sodium ions are charged, mobile cations. Alkaline earth metals present in tap water, such as calcium and magnesium, are exchanged with the sodium cations of the resin as the water passes through the bed of ion exchange resin beads.

[0048] The removal of calcium and magnesium ions from water by exchange with sodium ions via a weakly acidic cation exchange resin is not limited to water purification / softening applications, but also includes softening liquids such as clay suspensions, sugar syrup, and blood to make them suitable for further processing. When the exchange capacity of the ion exchange resin is exhausted, the acidic form of the resin can be regenerated using a weak acid, and then the acidic form of the resin can be converted back to the sodium form using dilute sodium hydroxide. Similarly, anion exchange resins containing anionic functional groups remove anions such as nitrates and sulfates from solutions. Anion exchange resins can also be regenerated, for example, with a sodium hydroxide solution. Due to the reversibility of the ion exchange process, the ion exchange resin can be repeatedly used for long periods before replacement becomes necessary.

[0049] The effective lifespan of an ion exchange resin is related to several factors, including, but not limited to, the amount of swelling and shrinkage that occurs during the ion exchange and regeneration processes, and the amount of oxidizing agent present in the fluid passing through the resin bed.

[0050] Cation exchange resins are typically highly crosslinked polymers containing carboxylic acid groups, phenolic groups, phosphonic acid groups, sulfonic acid groups, and approximately equal amounts of mobile, exchangeable cations. Anion exchange resins are similarly highly crosslinked polymers containing amino groups and approximately equal amounts of mobile, exchangeable anions. A suitable exchange resin is one that (a) has enough crosslinking to make the resin insoluble and has low swelling, (b) has sufficient hydrophilicity to allow ions to diffuse throughout its structure, (c) contains sufficiently accessible mobile cation or anion exchange groups, (d) is chemically stable and resistant to degradation during normal use, and (e) is denser than water when swollen.

[0051] Description of bead production from powder: As mentioned above, commercially available adsorbents are often highly porous and provide a large surface area. When such inorganic adsorbents (a) are commercially available as powders rather than as porous beads, it may be advantageous to produce beads from such powders.

[0052] Various methods for producing porous beads are described in the literature. The highest porosity is usually achieved by flocculation. In flocculation apparatus, a binder solvent is added to the particles. This apparatus can use any type of mixer, such as a plow shear mixer, free-fall mixer, fluidized bed, or granulite plate. Another method is to create a suspension of powder and binder, which is then dried, for example, in a spray dryer or drum dryer. Press flocculation in an extruder, pelletizer, or tablet press is also possible. To obtain porosity, it is preferable to prepare a sponge from the powder or to add a material that is then removed, for example, by combustion or dissolution.

[0053] To obtain a product with a stable shape and to prevent the material from collapsing later during application, the materials can then be sintered together, for example, by calcination.

[0054] Typically, porous beads are used for adsorption or ion exchange. In most cases, fixed-bed adsorbents or ion exchangers are used. However, fluidized-bed adsorbents or pulsed-bed adsorbents can also be used. If the adsorbent has a short lifespan, solid-liquid separation can be performed afterward using a moving bed or agitated container.

[0055] In a fixed-bed system, adsorption columns or ion exchange columns are arranged in series or parallel, and the fluid may be operated in upflow or downflow mode. When the bed becomes saturated with adsorbent, the adsorbent is replaced or regenerated. If the columns are continuous, the next bed in the sequence becomes the first bed, and a new bed is added to the final position.

[0056] When using powder as an adsorbent, adsorption is performed in batches within a stirring vessel, and then liquid-solid separation can be performed in batches or continuously, for example, by a filter press or membrane separation. It is also possible to use a stirring vessel cascade in continuous mode.

[0057] Treatment of discharged inorganic adsorbents (a): Hydroxyapatite and fluoroapatite are used as raw materials for phosphate-containing fertilizers and phosphate production. The apatite structure is dissolved with a strong acid such as sulfuric acid or nitric acid, and the dissolved phosphate is further treated to phosphate or a phosphate salt. Therefore, the fluoride-containing apatite obtained by the claimed method is a valuable raw material and can be introduced into these industrial processes.

[0058] The present disclosure is further illustrated by the following embodiments. [Examples]

[0059] Abbreviation: In this disclosure, atmospheric pressure means 1 atm or 10¹³ millibars. "Normal conditions" means atmospheric pressure and 20°C. Nl means normal liters, liters under normal conditions (1 atm, 20°C). PFA stands for perfluoroalkoxy polymer. ICP stands for inductively coupled plasma mass spectrometer unless otherwise specified. DI stands for deionized. BV stands for bed volume (dimensionless unit; for example, a 50 ml mini-column running at 1-2 BV / h results in a flow rate of 50-100 ml / h).

[0060] Percentages and quantities expressed in ppm (parts per million) refer to mass% or mass ppm unless otherwise defined, and may also be specified as wt.% or wt.ppm. The expressions mass% and wt% are used interchangeably. Where mentioned, the terms “room temperature” and “ambient temperature” refer to temperatures between approximately 18 and 25°C. XRD refers to powder X-ray investigation (radiation as indicated, typically 154 pm Cu k-alpha 1 radiation or 71 pm Mo k-alpha 1 radiation).

[0061] Description of the method: D 50 Particle size distribution measurements, including the determination of particle size, were performed in accordance with ISO 13320 EN:2009-10.

[0062] Elemental analysis of lithium, calcium, and manganese (in particular, performed to determine the Li, Ca, and Mn content of the particulate matter provided in step (a)): The reagents were deionized water, hydrochloric acid (36%), K2CO3-Na2CO3 mixture (dried), Na2B4O7 (dried), and 50% by volume hydrochloric acid (a 1:1 mixture of deionized water and hydrochloric acid (36%)), and all reagents were PA grade.

[0063] Sample preparation: 0.2–0.25 g of particulate matter from the main process (a) (typically obtained from waste lithium-ion batteries after the preliminary reduction process (i)) was weighed into a Pt crucible and subjected to K2CO3-Na2CO3 / Na2B4O7 molten hot immersion: the sample was burned in an uncovered flame and then completely ashed in a muffle furnace at 600°C. The remaining ash was mixed with K2CO3-Na2CO3 / Na2B4O7 (0.8 g / 0.2 g) and melted until a clear molten material was obtained. The cooled molten cake was dissolved in 30 mL of water and 12 mL of 50 vol% hydrochloric acid was added. This solution was filled to the specified volume of 100 mL. This procedure was repeated independently three times. Furthermore, a blank sample was prepared as a control.

[0064] measurement: The Li, Ca, and Mn content in the obtained solution was measured by inductively coupled plasma emission spectroscopy (ICP-OES). Instrument: ICP-OES Agilent5100SVDV, Wavelengths: Li 670.783nm, Ca 396.847nm, Mn 257.610nm, Internal standard: Sc 361.383nm, Dilution ratio: Li 100, Ca 10, Mn 100, Calibration: External.

[0065] Elemental analysis of fluorine and fluorides was performed to determine the overall fluorine content (waste sample) according to the standardized method for sample preparation: DIN EN14582:2016-12, and the detection method was ion-selective electrode measurement. DIN38405-D4-2:1985-07 (Water sample, fluoride determination using warm immersion of inorganic solid followed by acid-supported distillation and ion-selective electrode).

[0066] Other metallic impurities and phosphorus were similarly determined by elemental analysis using ICP-OES (inductively coupled plasma-emission spectroscopy) or ICP-MS (inductively coupled plasma-mass spectrometry). Total carbon was determined after combustion using a thermal conductivity detector.

[0067] Unless otherwise noted, the following standard methods were used to test the adsorbents of the present invention: A mixture containing 50-100 g of the target alkaline aqueous solution (typically a LiOH leaching filtrate with a Li concentration ranging from 0.5% to 3.4% by mass) and 0.1% to 10% by mass of adsorbent was prepared in an Erlenmeyer flask or a glass or HDPE bottle. All percentages were relative to the total mass of the mixture. The mixture was shaken at room temperature or 60°C for at least 24 hours (maximum 96 hours). The adsorbent was removed by filtration, and the filtrate was analyzed using ISE (ion-selective electrode) for fluoride, and ICP-OES (inductively coupled plasma emission spectroscopy) or AAS (atomic absorption spectroscopy) for alkali metals such as Li and other metals. The amount of solid fluoride loaded was determined by comparing the fluoride content with that of blind samples.

[0068] Educt 1: Synthetic Educt Sample 78.8g of spent cathode active material (nickel, cobalt, and manganese) is used, approximated by Li(Ni 0.34 Co 0.33 Mn 0.33 (Containing the same molar amount as O2), 62.2 g of graphite and organic carbon in the form of soot 47.0 g of organic electrolyte mixture (containing LiPF6) 7.4g of polyvinylidene fluoride as a binder, 2.4g of aluminum powder, 0.2g of iron powder, 2.0g of copper metal 200g of simulated used battery scrap containing It was placed in a 500 mL quartz round-bottom flask and attached to a rotary evaporator such that the flask was immersed in an oven. Within 4.5 hours, the rotating flask was heated to 800 °C over 2 hours under an argon flow (20 l / h), and this temperature was maintained for 1 hour under a dry air flow (20 l / h) before cooling to ambient temperature. A heat-treated material with a quantity of 173.3 g containing the phase composition of Ni / Co alloy, iron manganese oxide, Li2CO3, LiF, and graphite was obtained.

[0069] Educt 1a: Provision of a reduced mass from spent lithium-ion batteries ~1 t of mechanically processed battery scrap containing used cathode active material containing nickel, cobalt and manganese, organic carbon in the form of graphite and soot, and residual electrolyte, and further impurities including especially fluorine compounds, phosphorus and calcium was processed to obtain a reduced mass (according to the method described in Jia Li et al., Journal of Hazardous Materials 302 (2016) 97 - 104). The atmosphere in the roasting system was air, and its oxygen reacted with the carbon in the battery scrap to produce carbon monoxide. The processing temperature was 800 °C.

[0070] After cooling to room temperature after the reaction, the heat-treated material was recovered from the furnace and mechanically processed to obtain particulate matter, which was analyzed by X-ray powder diffraction (Figures 4 and 5: Mo Ka radiation, Figures 6 and 7: Cu Ka radiation), elemental analysis (Table 1) and particle size distribution (Table 2).

[0071] The Li content was 3.6 mass%, which functions as a reference for any further leaching examples (see below). Fluorine was represented mainly as inorganic fluoride (88%). The particle size was well below 1 mm. D 50 was determined to be 17.36 μm.

[0072] By comparing the obtained XRD patterns with calculated reference patterns for Ni (identical to that of CoxNi1-x, x=0~0.6), Co, Li2CO3, and LiAlO2, it was concluded that Ni was exclusively present as a metallic phase, either as pure Ni or as an alloy with Co. For clarification, this result was confirmed by applying two different radiation sources. The presence of metallic nickel was supported by qualitative observation that the entire sample exhibited typical ferromagnetic behavior when in contact with a permanent magnetic material. As lithium salts, Li2CO3 and LiAlO2 were clearly identified by their characteristic diffraction patterns.

[0073] The composition of the obtained black powder (PM) was as shown in Table 1.

[0074] [Table 1]

[0075] [Table 2]

[0076] Educt 2: Leaching using Ca(OH)2 5 g of the above-mentioned reduced battery scrap material (obtained as shown in Example 1a) was placed in a PFA flask and mixed with 5, 1.5, 1.0, and 0.5 g of solid Ca(OH)2, respectively. 200 g of water was added while stirring, and the entire mixture was refluxed for 4 hours.

[0077] After 4 hours, the solids were filtered, and the filtrate sample was taken and analyzed for Li, F, carbonate, OH, and Ca. The results are summarized in Table 3 below.

[0078] [Table 3]

[0079] Educt 2a: Leaching using Ca(OH)2, addition of solids to liquids Example 2 was repeated, except that 5 g of the black powder obtained as shown in Example 1a and a predetermined amount of solid Ca(OH)2 were simultaneously added to 200 g of water while stirring. The results were similar to those reported in Table 2.

[0080] Educt 3: Higher solids content 10, 20, and 30 g portions of the particulate matter (PM) described in Example 1a were placed in PFA flasks and mixed with solid Ca(OH)2 at a fixed mass ratio of PM:Ca(OH)2 = 3.3:1. Further treatment with the addition of 200 g of water followed the procedure in Example 2, except that each sample was refluxed for 6 hours. The results are shown in Table 4.

[0081] From these results, it was concluded that the efficiency of the leaching method of the present invention is not affected by the PM solid content.

[0082] [Table 4]

[0083] Educt 4: Parameter changes Following the procedure of Example 2a, solid Ca(OH)2 and particulate matter (PM) described in Example 1a were added to 836.8 g of preheated water in a baffled glass reactor while stirring (3-stage cross-beam stirrer, 60 mm diameter). Stirring was continued at a constant temperature for the time (t) shown in Table 5, after which the solid was filtered off and the filtrate sample was analyzed. The amounts of Ca(OH)2 and PM, temperature, stirring parameters, and analytical results (% = g found in 100 g of filtrate) are also summarized in Table 5.

[0084] [Table 5]

[0085] Educt 5: Solid LiOH from leached lithium filtrate The filtrate obtained from the process according to Example 2 was further processed to obtain solid LiOH as a monohydrate: 1 L of filtrate containing 0.21 mass% lithium was concentrated by evaporation (40°C, 42 mbar), and finally dried by applying 40°C and a constant flow rate of nitrogen for 24 hours. Figure 8 shows the obtained LiOH monohydrate along with trace impurities of Li2CO3. The latter is due to contact with air at almost all process steps. Following carbon-based impurities, elemental analysis detected F, Na, Ca, K, and Cl as major impurities (>200 ppm), and Al and Zn as trace impurities (<200 ppm).

[0086] Example of fluoride extraction (batch process) A mixture of 0.1% to 10% by mass of adsorbent and 50 to 100 g of LiOH leaching filtrate with a Li concentration of 0.5% by mass (diluted filtrate) or 3.4% by mass (concentrated filtrate) obtained in the above educt example was prepared in an Erlenmeyer flask. Alternatively, a glass or HDPE bottle can be used. This mixture was shaken for 48 hours (for inorganic adsorbent) or 24 hours (for resin adsorbent) at the temperatures shown in Table 6 or Table 7 below. The adsorbent was then removed by filtration, and the filtrate was analyzed using ISE (ion-selective electrode) for fluoride, and ICP-OES (inductively coupled plasma emission spectroscopy) or AAS (atomic adsorption spectroscopy) for Li and other metals. The amount of fluoride loaded onto the solid was determined by comparing the fluoride content with a blind sample (a sample without added adsorbent).

[0087] The results obtained using alkaline earth salt adsorbents are summarized in Tables 6a and 6b below, and the results obtained using ion exchange resins loaded with trivalent cations are summarized in Tables 7(a and b) below. Comparative tests were conducted using a different type of mineral adsorbent (La(OH)3) and a resin loaded with tetravalent Zr instead of trivalent cations.

[0088] The cation-bonded ion exchange resin was loaded with the indicated cations according to the following procedure: A mini-column was set up and an appropriate amount of resin was packed in a delivery form. The resin was first thoroughly washed with DI water to remove any possible contaminants, dirt, and debris.

[0089] The resin was doped by passing an aqueous solution containing a soluble salt of the desired metal, such as aluminum(III) chloride, lanthanum(III) chloride, or zirconyl(IV) chloride, through the resin bed at a low speed (usually 1-2 BV / h or more).

[0090] A very large excess amount of salt (usually expressed as eq / l or mol / l) was supplied to the resin compared to the active functional groups of the resin. The loading solution was passed through the resin bed multiple times using a recirculation pump to increase the contact time and enhance the possibility and effectiveness of metal loading. Metal loading was generally carried out at room temperature, but may be carried out at different temperatures. Next, the resin was thoroughly rinsed with DI water to wash away any possible doping solution residue. The resin with the metal loaded was ready for immediate use.

[0091] The ion exchange resin was based on a divinylbenzene crosslinked polystyrene matrix and had the following binding sites: Lewatit® Monoplus TP207 and Lewatit® Monoplus TP208 contain chelating iminodiacetate groups (cation-bonded resin). Lewatit® Monoplus TP260 contains chelateable aminomethylphosphonic acid groups (cation-bonded resin). Lewatit® Monoplus type ion exchange resins are commercially available, particularly from Lanxess.

[0092] [Table 6]

[0093] [Table 7]

[0094] *) Magnesium carbonate DC90S / C, manufactured by Dr. Paul Lohmann GmbH, 4MgCO3*Mg(OH)2*5H2O, with 10% gelatinized starch; white, coarse granules; particle size <0.8 mm, approximately 99.0%. **) MagGran(registered trademark) 82660; MgO 98.8%; Particle size: 10%: 20-30 mesh, 52%: 30-60 mesh, 32%: 60-100 mesh, 6%: >100 mesh. ***) A white, fine powder containing over 99% MgO. ****) MagGran(registered trademark) 82600; MgO 100.0%; Particle size: 16%: 20-30 mesh, 66%: 30-60 mesh, 12%: 60-100 mesh, 5%: >100 mesh. #) MagGran(registered trademark) MC81820; Particle size 250-600 micrometers, approximately 85%. Ca-hydroxyapatite 1: Technical grade Aldrich powder (Lot #BCC5175); purity >90%, D50 = 7.0 μm. Aldrich powder containing Ca-hydroxyapatite 2:99.9% (Lot#MKCG0750); granule size = 0.5~2mm. Ca-Hydroxyapatite 3: Technical grade Aldrich powder (Lot #BCC5175), purity >90%, granular (0.5~2mm) Ca-Hydroxyapatite 4: 99% Solvay Capterall® powder (D 50 (=22μm).

[0095] [Table 8]

[0096] [Table 9]

[0097] Fluoride reduction in the column Experimental Setup: In the column experiment, the application of a filter column running continuously on a filter bed with a fixed supply flow was simulated. A standard experimental setup is shown in Figure 1.

[0098] The supply solution is stored in a tank (T1). The tank is mounted on a balance so that the amount of solution consumed can be easily determined by measuring its mass. A pump (P) delivers the supply solution at a continuous volumetric flow rate to the head of the ion exchange column (C). The supply flow can be heated by passing it over a heat exchanger (H) located between the storage tank (T1) and the column (C). The column (C) is equipped with a heating jack. Proper insulation of the column (C), heat exchanger (H), and associated tubing is recommended.

[0099] The three-way valve (V1) at the top of the column is used to remove gas bubbles from the column head. This can also be used to supply regenerator or rinse water in a later step of the process.

[0100] The column outlet has a second three-way valve (V2), a siphon (S), and a third three-way valve (V3). Valve V2 is used to drain liquid from the column as needed. It also functions as an inlet or outlet for regeneration, rinsing, and backflushing operations.

[0101] The siphon (S) is connected to V2 and V3 by a flexible rubber tube. By changing its position, the water level in the column can be adjusted: the height of the siphon can control the liquid level in the column. The siphon prevents the column from being depleted by the suction effect generated from the outlet flow.

[0102] Behind the siphon, the product flows through valve V3 towards the purified product recovery tank T2. Valve V3 can be used for sampling.

[0103] Using a balance under T2, the mass of the filtered product can be measured.

[0104] In the configuration shown in Figure 1, the column is operating in downflow mode. This column can also be operated in the upflow direction. In this case, the positions of the supply and discharge pipes are changed as appropriate. In some cases, it may not be necessary to use a siphon.

[0105] Online measurement probes, such as pH, temperature, and electrical conductivity (LF;λ), are installed. By monitoring both the feed and discharge flows online, parameters that can later be used for process control purposes can be identified. Automated samplers are effective for conducting column experiments overnight and are therefore useful for monitoring breakthrough curves with cycle times longer than one day. If the operating capacity is the target parameter to be determined, the dynamic adsorption method should not be stopped during running tests. Stopping it would hinder the accumulation of concentration profiles within the column and the pores of the resin beads. Therefore, interrupted filtration tests will not accurately depict the effects of motion resistance.

[0106] Further improvements are needed for regeneration and rinsing. Additional containers will be installed for storing new regeneration solution and rinse water, and for collecting used regeneration solution and rinse water.

[0107] Pumps are also installed to control the transport of these liquids. Regeneration can be performed with reverse or simultaneous current, compared to the direction of flow applied in the service phase.

[0108] To implement a "read-lag mode" that alternately operates two columns, running one while regenerating the other, more advanced settings are required.

[0109] Filtration experiments should not be stopped when the first signs of breakthrough are observed. They should continue until the breakthrough stage is reached. This proves whether breakthrough truly occurred and that it was not merely a false breakthrough caused by one or two high concentration values. The complete shape of the breakthrough curve allows for conclusions to be drawn about the rate and / or damping effect. To measure the complete breakthrough curve, a feed volume of at least 50% excess is prepared, based on the filtrate volume calculated (estimated) for the breakthrough point.

[0110] Column preparation: The column (ID 30 mm, H 500 mm) is filled with the specified amount of adsorbent (e.g., resin) (e.g., 340 ml = 1 BV). When filling with resin, the column must not be empty; half of the column volume must already be filled with DI water.

[0111] Before supplying the stock solution to the column, distilled water of several BVs was passed through the column. For example, but not limited to, water was passed until the pH was approximately 7 or until the LF did not exceed 3 mS / cm.

[0112] After the water test, the product flow was supplied to the column and the operation time was performed. For example, the LiOH solution was delivered to the column in upflow mode at room temperature or above (e.g., 60°C) at 340 ml / h (1 BV / h). The specific rate can usually be in the range of 0.1 BV / h to 100 BV / h or less. In particular, when using inorganic adsorbents, the pressure may be increased, but compression of the adsorbent should be avoided.

[0113] Column wastewater samples were taken sequentially according to a predetermined plan, taking into consideration the conductivity of the outlet in particular: For λ ≤ 100 mS / cm: Diluted flows were collected and disposed of separately. For λ > 100 mS / cm: One fraction was collected for each BV. Loading stopped at 48BV.

[0114] Any other criteria for verification and suspension may be used in combination as needed.

[0115] After loading the adsorbent, the bed was rinsed with distilled water of several BV values, for example 2 BV / h, until the pH was approximately 7 or the LF was no higher than 3 mS / cm, to wash away any remaining traces of LiOH products. During the rinsing process, samples of the column effluent were taken sequentially according to a predetermined plan, taking into account, for example, the conductivity of the effluent (but not solely): For λ ≥ 3 mS / cm: One fraction was collected for each BV. When λ < 3 mS / cm, rinsing was stopped.

[0116] During the regeneration process (if necessary), an alkaline solution (for example, NaOH solution with a concentration ranging from 4% to 20% by mass, though not exclusively) was pumped through the column at, for example, 2 BV / h. Regeneration could be carried out simultaneously or counter-clockwise at room temperature or higher. During the regeneration process, samples of the column effluent were taken sequentially according to a predetermined plan, advantageously taking into account the pH of the outlet: If pH < 12: Diluted flows were collected and discarded separately. If pH > 12: One fraction was taken from each BV (Body Volume). Playback stopped after 18BV.

[0117] After the regeneration process, the floor was rinsed with distilled water of several BV values, for example 2 BV / h, until the pH reached approximately 7, or the LF was no higher than 3 mS / cm, to wash away any remaining traces of the NaOH solution.

[0118] Subsequently, another loading cycle was performed. The adsorbent was either regenerated or removed from the column and replaced with new adsorbent.

[0119] The collected samples were analyzed for their target components as appropriate, and the loading and regeneration experiments were evaluated.

[0120] Next, the present disclosure will be described with reference to the following embodiments, but it should be understood that the present disclosure is not limited to these embodiments and can be implemented or carried out in other embodiments and in various other ways.

[0121] 1. A method for extracting fluoride from a solution, wherein the solution is as follows: a) Alkaline earth salts containing carbonate anions, oxo anions, sulfate anions, or phosphate anions, and alkaline earth salts containing mixtures of such anions or mixtures of such anions and hydroxyl anions, b) A cation-bonded resin loaded with one or more trivalent cations selected from trivalent cations of Al, Ga, In, Fe, Cr, Sc, Y, La, and lanthanides. This includes contacting with a more selected solid-phase adsorbent, and A method wherein the solution comprises more than 0.1 moles per liter of alkali hydroxide and / or alkalate dissolved in a polar solvent selected from water, lower alcohols, and mixtures thereof.

[0122] 2. The method according to Embodiment 1, wherein the solution is an alkaline aqueous solution.

[0123] 3. The solid-phase adsorbent is a) Alkaline earth salts including calcium phosphate, calcium hydroxyphosphate, calcium sulfate, magnesium carbonate, magnesium oxide, calcium hydroxyapatite and / or tricalcium phosphate, and b) A cation-bonded resin loaded with one or more trivalent cations selected from the trivalent cations of aluminum and lanthanum. A method according to embodiment 1 or 2, which is more selected.

[0124] 4. The method according to Embodiment 1 or 3, wherein the solution is an alkaline aqueous solution and / or methanol-alkaline solution containing more than 0.1 moles of alkali hydroxide and / or methanol per liter, and 50% by mass or more of the total liquid consists of water and / or methanol.

[0125] 5. A method according to any one of the embodiments described above, wherein the alkali hydroxide is a lithium hydroxide and the alkali alcoholate is a lithium alcoholate, such as methanelate.

[0126] 6. A method according to any one of the above embodiments, wherein the solution of the alkali hydroxide and / or alkalate contains 0.2 moles or more, or 0.35 moles or more, of alkali hydroxide and / or alkalate in a dissolved state per liter.

[0127] 7. A method according to any one of the above embodiments, wherein the contact between the alkaline solution liquid and the solid-phase adsorbent is carried out at a pressure between 0.1 bar and 100 bar, and at a temperature higher than the melting temperature of the liquid under actual pressure conditions but below the boiling point of the liquid, or between 0°C and 150°C.

[0128] 8. The solid-phase adsorbent (a) is a powder or granular material, or has a diameter (D 50 A method according to any one of the above embodiments, wherein the material is in the form of beads or pellets measuring 10 micrometers to 10 mm, or 100 micrometers to 5 mm.

[0129] 9. A method for producing high-purity lithium hydroxide from lithium materials, the following: A process of processing a lithium material to form a water-soluble lithium salt solution, wherein the lithium material is selected from brine, ore, slag and flue ash, and the lithium material forms an alkaline solution containing more than 121 ppm by mass of ionic fluoride, this amount relative to the lithium content of the solution, and optionally converting the lithium salt to lithium hydroxide, and A step for purifying lithium hydroxide according to any one of Embodiments 1 to 8. A method that includes this.

[0130] 10. A method according to Embodiment 9, wherein the process includes acid leaching, followed by dissolving a lithium salt in a polar solvent to form a solution containing more than 121 ppm by mass of ionic fluoride, the amount being relative to the mass of lithium in the solution, thereby converting the lithium salt to lithium hydroxide.

[0131] 11. The method according to Embodiment 9, wherein the process for forming a water-soluble lithium salt comprises a heat treatment process followed by a lithium extraction process using a polar solvent, optionally in the presence of an alkaline earth oxide or hydroxide, and the water-soluble lithium salt is lithium carbonate, lithium bicarbonate, and / or lithium hydroxide.

[0132] 12. A method for producing high-purity lithium hydroxide from lithium materials, the following: A process of processing a lithium material to form a water-soluble lithium salt solution, wherein the lithium material is selected from lithium-ion batteries, lithium-ion battery components, or manufacturing scrap from the manufacture of lithium-ion batteries, cells, or electrode active materials, and the lithium material forms an alkaline solution containing more than 121 ppm by mass of ionic fluoride, the amount of which is relative to the lithium content of the solution. The process of converting lithium salts to lithium hydroxides, A step of dissolving and purifying a lithium hydroxide solution according to any one of Embodiments 1 to 8. A method that includes this.

[0133] 13. A method according to Embodiment 12, wherein the process comprises an acid leaching process, the lithium salt being a salt of this acid anion, and the lithium salt subsequently being converted to lithium hydroxide.

[0134] 14. A method for producing high-purity lithium hydroxide from lithium-containing wastewater, the following: i) A step of concentrating the lithium content of wastewater, or precipitating, extracting, or adsorbing lithium ions, wherein the wastewater contains ionic fluoride in a concentration exceeding 121 ppm relative to the lithium content of the wastewater, and ii) A step of converting the concentrated lithium salt from step i) into a solution of lithium hydroxide in a polar solvent, and iii) A step of purifying lithium hydroxide according to any one of Embodiments 1 to 8. A method that includes this.

Claims

1. A method for extracting fluoride from a solution, wherein the solution is as follows: a) Alkaline earth salts containing carbonate anions, oxo anions, sulfate anions, or phosphate anions, and alkaline earth salts containing mixtures of such anions or mixtures of such anions and hydroxyl anions, b) A cation-bonded resin loaded with one or more trivalent cations selected from trivalent cations of Al, Ga, In, Fe, Cr, Sc, Y, La, and lanthanides. This includes contacting with a more selected solid-phase adsorbent, and A method wherein the solution comprises more than 0.1 moles per liter of alkali hydroxide and / or alkolate dissolved in a polar solvent selected from water, C1-C4 alcohols, and mixtures thereof.

2. The method according to claim 1, wherein the solution is an alkaline aqueous solution.

3. The solid-phase adsorbent is a) Alkaline earth salts containing calcium phosphate, calcium hydroxyphosphate, calcium sulfate, magnesium carbonate, magnesium oxide, calcium hydroxyapatite and / or tricalcium phosphate, and b) A cation-bonded resin loaded with one or more trivalent cations selected from the trivalent cations of aluminum and lanthanum. A method according to claim 1 or 2, more preferably selected.

4. The method according to claim 1 or 3, wherein the solution is an alkaline aqueous solution and / or methanol-alkaline solution containing more than 0.1 moles of alkali hydroxide and / or methanol per liter, and 50% by mass or more of the total liquid consists of water and / or methanol.

5. The method according to any one of claims 1 to 4, wherein the alkali hydroxide is a lithium hydroxide and the alkali alcoholate is a lithium alcoholate.

6. The method according to any one of claims 1 to 5, wherein the solution of the alkali hydroxide and / or alkalate contains 0.2 moles or more, or 0.35 moles or more, of alkali hydroxide and / or alkalate in a dissolved state per liter.

7. The method according to any one of claims 1 to 6, wherein the contact between the alkaline solution liquid and the solid-phase adsorbent is carried out at a pressure between 0.1 bar and 100 bar, and at a temperature higher than the melting temperature of the liquid under actual pressure conditions and below the boiling point of the liquid, or between 0°C and 150°C.

8. The solid-phase adsorbent (a) is a powdered or granular material, or has a diameter (D ５０ The method according to any one of claims 1 to 7, wherein the material is in the form of beads or pellets measuring 10 micrometers to 10 mm, or 100 micrometers to 5 mm.

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