Method for recovering valuable metal elements from waste battery material

Abstract

The present disclosure provides a method of recovering a spent battery cathode material comprising lithium and at least one of nickel, cobalt and / or manganese, the method comprising: heating the spent battery cathode material in a reducing atmosphere to form a heat-treated spent battery cathode material comprising LiF and one or more of LijO, LiOH and LijCOs; washing the heat treated waste battery cathode material in an aqueous solvent to extract lithium-containing species and fluorine-containing species wherein the aqueous solvent is free of alkaline earth metal hydroxides or other species intended to reduce or prevent soluble fluorine species from remaining dissolved in the aqueous solvent; separating an aqueous solvent comprising lithium and fluorine species from the heat treated waste battery material; after separating an aqueous solvent comprising lithium and fluorine species from the heat-treated waste battery material, treating the aqueous solvent to separate lithium species from fluorine species; recycling a lithium substance in the form of lithium hydroxide or lithium carbonate; forming an acidic aqueous recovery feed comprising one or more of nickel, cobalt and / or manganese by leaching the heat treated waste battery cathode material with a mineral acid after the step of separating the aqueous solvent from the heat treated waste battery material; and recovering one or more of nickel, cobalt and / or manganese from the acidic aqueous recovery feed by a further process step selected from one or more of solvent extraction, solid phase extraction, electrochemical extraction and precipitation processes.

Description

[0001] Related Applications

[0002] This application claims priority to UK patent application No. GB2213410.0 filed on September 14, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a method for recovering valuable metal elements from waste battery materials. The method is applicable to waste battery cathode materials containing lithium, fluorine substances and one or more of nickel, cobalt and / or manganese. However, it should be understood that the present invention is not limited to this specific field of application. Background Art

[0004] Lithium-ion batteries are now ubiquitous in modern society, used not only in small portable devices such as mobile phones and laptops, but also increasingly in electric vehicles. Lithium-ion batteries typically contain a cathode and a graphite anode separated by an electrolyte through which lithium ions flow during the charge and discharge cycles. The cathode in a lithium-ion battery can contain a lithium transition metal oxide, such as lithium nickel oxide, lithium cobalt oxide, or lithium manganese oxide.

[0005] While lithium-ion batteries and other modern rechargeable batteries offer a promising low-carbon energy source for the future, one concern is that the metals required to manufacture these batteries, such as lithium, nickel, cobalt and / or manganese, are often expensive due to their limited availability and difficulty in extracting from natural resources. Therefore, a method of recovering or purifying metals present in batteries, such as those present in the cathode of a battery, is needed to provide materials that can be used as raw materials in battery manufacturing.

[0006] In the process of battery material recovery, a waste solution containing valuable metal elements such as cobalt and nickel is produced, which can be used to make new battery materials if these metal elements can be extracted with sufficient purity. This solution can be produced by leaching from waste battery materials, including so-called "black mass", that is, a mixture of valuable metals and unwanted impurities. Leaching can be carried out using inorganic acids such as sulfuric acid to produce an acidic aqueous recovery feed containing a mixture of valuable metal substances. One or more valuable metal elements can then be recovered from the acidic aqueous recovery feed by one or more additional process steps selected from solvent extraction, solid phase extraction, electrochemical extraction and precipitation processes.

[0007] In a method for a battery cathode material comprising lithium, manganese, cobalt and nickel, all of these elements are dissolved in an inorganic acid and then selectively separated from an aqueous acidic feed. However, it may be difficult to extract manganese, cobalt and nickel without lithium contamination, and conversely, it may also be difficult to extract lithium without introducing sodium ion contamination during the treatment of the acidic feed. Therefore, it has been proposed that for waste battery materials comprising lithium and one or more of nickel, cobalt and / or manganese, it may be advantageous to extract lithium from the waste battery material before forming an acidic aqueous recovery feed comprising one or more of nickel, cobalt and / or manganese. For example, WO2022 / 079409 discloses the selective leaching of lithium from waste battery materials using an organic acid such as formic acid before forming an acidic aqueous recovery feed comprising one or more of nickel, cobalt and / or manganese by dissolution with an inorganic acid.

[0008] Another example of recovering lithium from waste battery materials is disclosed in WO2020011765. This prior art document discloses a method comprising: heating a lithium-containing transition metal oxide material to a temperature of 200°C to 900°C in the presence of hydrogen; leaching lithium species from the heat-treated material with water or a weak acid; and recovering lithium in the form of hydroxide or carbonate from the leachate by precipitation.

[0009] Another example of recovering lithium from waste battery materials is disclosed in WO2021018778. This prior art document discloses a method similar to the method described in WO2020011765, but uses an aqueous solution of an alkaline earth metal hydroxide (e.g., calcium hydroxide) to leach lithium species from heat-treated waste battery materials. In other words, the method includes: heating a lithium-containing transition metal oxide material in the presence of hydrogen; leaching lithium species from the heat-treated material using an aqueous solution of an alkaline earth metal hydroxide; separating the leachate from the remaining solid residue; and recovering lithium in the form of hydroxide or carbonate from the leachate by precipitation. The alkaline earth metal hydroxide reacts with a soluble fluorine-containing substance to precipitate an alkaline earth metal fluoride. Therefore, fluorine is retained in the solid waste battery material residue instead of being dissolved into the leachate with the lithium species. This has the advantage that the lithium-containing leachate has much less fluorine contamination and can improve the purity of the lithium hydroxide or lithium carbonate precipitated from the leachate (for example, when compared to the method described in WO2020011765).

[0010] The purpose of the present specification is to at least partially address this problem, or at least provide a useful alternative.

[0011] It is an object of the present invention to overcome or ameliorate one or more disadvantages of the prior art, or at least to provide a useful alternative. Summary of the invention

[0012] The method described in WO2021018778 focuses on improving the purity of the lithium-containing leachate by ensuring that the fluorine in the soluble fluorine-containing substance such as LiF is retained in the solid residue of the waste battery material. In this regard, an alkaline earth metal hydroxide is used to ensure that any fluoride dissolved in the aqueous leachate is precipitated back into the solid residue in the form of alkaline earth metal fluoride, so that lithium is leached mainly in the form of LiOH. Although this method can improve the purity of the lithium-containing leachate, it is problematic if the remaining solid residue of the waste battery material is subsequently subjected to inorganic acid leaching to form an acidic aqueous recovery feed containing one or more of nickel, cobalt and / or manganese. This is because the alkaline earth metal fluoride retained in the solid residue of the waste battery material will cause HF to be formed in the acidic aqueous recovery feed. For example, although calcium fluoride is insoluble in water and therefore does not enter the lithium leachate in the aqueous lithium leaching step, it reacts with sulfuric acid to form calcium sulfate and hydrogen fluoride (HF). In view of the serious environmental health and safety risks and materials compatibility issues associated with HF, it is desirable to remove fluorine-containing species present in spent battery materials which would result in the generation of HF if the material were subjected to mineral acid dissolution.

[0013] Therefore, the present specification provides a method for recovering spent battery cathode material containing lithium and at least one of nickel, cobalt and / or manganese, the method comprising:

[0014] Heating the spent battery cathode material in a reducing atmosphere to form a heat-treated spent battery cathode material comprising LiF and one or more of Li2O, LiOH and Li2CO3;

[0015] washing the thermally treated spent battery cathode material in an aqueous solvent (e.g., water) to extract lithium-containing species and fluorine-containing species, wherein the aqueous solvent does not contain alkaline earth metal hydroxides or other substances intended to prevent fluorine from remaining dissolved in the aqueous solvent;

[0016] separating an aqueous solvent containing lithium and fluorine species from the thermally treated spent battery material;

[0017] After separating the aqueous solvent containing lithium and fluorine species from the thermally treated waste battery material, treating the aqueous solvent to separate the lithium species from the fluorine species;

[0018] Recovering lithium material in the form of lithium hydroxide or lithium carbonate;

[0019] After the step of separating the aqueous solvent from the thermally treated spent battery material, leaching the thermally treated spent battery cathode material with a mineral acid to form an acidic aqueous recovery feed comprising one or more of nickel, cobalt and / or manganese; and

[0020] One or more of nickel, cobalt and / or manganese are recovered from the acidic aqueous recovery feed by an additional process step selected from one or more of solvent extraction, solid phase extraction, electrochemical extraction and precipitation processes.

[0021] Therefore, the method of the present invention is intended to extract lithium species (e.g., in the form of LiOH and / or Li2CO3) and soluble fluorine species (e.g., in the form of LiF) from the waste battery cathode material before the waste battery cathode material is subjected to inorganic acid leaching. Only after the lithium / fluorine-containing leachate is separated from the heat-treated waste battery cathode material, the leachate is subjected to a treatment step to separate lithium and fluorine. The step of treating the aqueous solvent to separate the lithium species from the fluorine species may include adding an alkaline earth metal hydroxide so that the fluorine species is precipitated in the form of an alkaline earth metal fluoride, and then separating the alkaline earth metal fluoride from the aqueous solvent by a solid-liquid separation process. However, the difference here is that the alkaline earth metal hydroxide is added to the aqueous solvent only after the aqueous solvent is separated from the heat-treated waste battery material. The advantage of doing this is that high-purity LiOH (or Li2CO3) can be obtained, while also ensuring that HF-forming substances (e.g., alkaline earth metal fluorides) will not remain in the solid waste battery material in the subsequent inorganic acid leaching step. The lithium is then recovered from the aqueous solvent, either by precipitation as LiOH or by adding CO2 in a manner similar to that described in WO2021018778 to recover it in the form of Li2CO3.

[0022] As an alternative to using alkaline earth metal hydroxides to precipitate fluoride, other reactants may be used to precipitate fluoride species, thereby separating fluoride and lithium species using a solid-liquid separation process. Examples of fluoride precipitation reactants include chlorides, hydroxides, carbonates, bicarbonates, acetates, formates of alkali and alkaline earth metals, and mixtures of two or more of these reactants. For example, a combination of CaCl2 and Ca(OH)2 or NaOH and CaCl2 may be used in the fluoride precipitation process. Other examples include calcium chloride, calcium bicarbonate, calcium acetate, and calcium formate. In this regard, it is also noted that calcium hydroxide has a poor solubility and is therefore not preferred for precipitating large amounts of CaF2. Using a more soluble calcium salt allows for better control of the Ca in solution. 2+ concentration to precipitate a large amount of CaF2.

[0023] As an alternative to using one or more of the above reactants to precipitate fluorine, a solid phase extractor (SPE) can be used to extract fluorine from an aqueous solvent containing fluorine and lithium species. The SPE can be a silica-based adsorbent, a metal-based adsorbent, and / or an ion exchange resin that can adsorb / react with fluorine. Examples of ion exchange resins include amino-methylphosphonic acid functionalized chelating resins preloaded with zirconium or aluminum, strongly basic anion exchange resins containing quaternary ammonium functional groups, preloaded with metal ions (e.g., Fe 3+ 、Al 3+ 、Ce 3+ and / or La 3+ ) or cryptands. Preferably, the SPE is a silica-based adsorbent, such as a glass material, such as a barium silicate glass material which can be provided in the form of a glass powder. The fluorine-containing wash solution can be passed through a packed column or bed with such an adsorbent to remove fluorine. The adsorbent can be periodically replaced and / or treated to remove fluorine and regenerated for reuse.

[0024] Heat treatment under a reducing atmosphere is intended to decompose the waste battery cathode material, thereby releasing lithium. In principle, as the lithium nickel manganese cobalt oxide (NMC) cathode material is reduced, Li2O is released from the NMC cathode material (the NMC structure collapses). According to the partial pressure of water during the heat treatment process, Li2O can be hydrolyzed into LiOH during the thermal process. XRD analysis of the reduced heat-treated material shows an example with Li2O or LiOH. Whether lithium is in the form of Li2O or LiOH, during washing in an aqueous solvent, these lithium species are hydrolyzed and extracted into the solution in the form of LiOH. In addition, the reduced, heat-treated waste battery cathode material contains LiF and may also contain some Li2CO3, both of which are also dissolved in the aqueous solvent during washing. Therefore, after washing the heat-treated waste battery cathode material in an aqueous solvent, the aqueous solvent contains LiF and one or two of LiOH and Li2CO3 (and there may also be a small amount of other lithium species, such as lithium phosphate). However, it should be noted that LiF is more difficult to dissolve than LiOH and Li2CO3. Thus, while the first washing cycle may extract substantially all of the Li2O (in the form of LiOH), LiOH and Li2CO3, in order to ensure that substantially all of the LiF is also extracted, it may be advantageous to subject the thermally treated spent battery cathode material to one or more additional washings in an aqueous solvent, the aqueous solvent resulting from the one or more additional washings comprising at least LiF, but if residual amounts of LiOH and Li2CO3 remain in the solid material after the first washing cycle, these one or more subsequent washings may also release small amounts of LiOH and Li2CO3.

[0025] Although the main purpose of heat treatment is to decompose the waste battery cathode material to convert lithium into a form that can be washed out of the material with an aqueous solvent, the heat treatment can also volatilize and remove a portion of the fluorine-containing substances that would otherwise be washed out during the subsequent lithium aqueous phase leaching process. This can reduce the amount of fluorine substances washed out during the subsequent lithium aqueous phase leaching process, thereby reducing the number of washing cycles required to remove soluble fluorine substances from the solid heat-treated waste battery cathode material. However, if the heat treatment is carried out at a sufficiently high temperature to cause the insoluble fluorine components (e.g., polyvinylidene fluoride PVDF) to decompose into soluble fluorine substances, this may have the opposite effect, i.e., increasing the amount of soluble fluorine substances in the waste battery cathode material, thereby requiring more washing to extract all the soluble fluorine, which would otherwise result in the formation of HF during the mineral acid leaching. Therefore, a balance can be reached, i.e., heating the material to a temperature sufficient to release lithium in soluble form, while the temperature is not so high that the insoluble fluorine components are decomposed to release soluble fluorine. For example, the spent battery cathode material can be heated to at least 200°C, 250°C, 300°C, 350°C or 400°C in a reducing atmosphere; not more than 600°C, 550°C, 500°C, 450°C, 400°C, 350°C, 300°C or 250°C; or a temperature within a range defined by any combination of the above lower and upper limits. The heating can be performed for at least 5 minutes, 10 minutes, 20 minutes or 30 minutes; not more than 3 hours, 2 hours or 1 hour; or a time within a range defined by any combination of the above lower and upper limits. The reducing atmosphere can be hydrogen or hydrogen in an inert gas, which is optionally nitrogen.

[0026] It has also been found that a small amount of lithium is lost during the thermal treatment. Although the calculated lithium losses are within experimental error, a small amount of lithium loss may be at least partially caused by reactions with the container in which the material is placed during the thermal treatment. Therefore, it is advantageous that the thermal treatment is carried out in a container formed of one or more of nickel, nickel alloys, graphite, silicon carbide, highly dense alumina ceramics or mullite porcelain or a container lined with such materials. This helps to reduce lithium losses during the thermal treatment.

[0027] In addition to the reduction heat treatment as described above, optionally, the method also includes heating the waste battery cathode material in an oxidizing atmosphere before or after heating the waste battery cathode material in a reducing atmosphere. This oxidative heat treatment can be used to remove volatile organics. However, as with the reduction heat treatment, care should be taken to avoid decomposing insoluble fluorine-containing substances such as PVDF into soluble fluorine substances, which require more washing to remove before leaching the material with inorganic acids. Therefore, heating the waste battery cathode material in an oxidizing atmosphere can be carried out at a temperature below 400°C, for example, at a temperature of 250°C to 350°C. The oxidizing atmosphere can include water and / or NH4OH in an oxidizing gas (e.g., air). For example, these additives can affect the amount of organic fluorine compounds formed during the oxidative heat treatment. In other words, it should also be noted that the reduction heat treatment can effectively remove volatile organics, and in some applications, the oxidative heat treatment may not be required. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to better understand the invention and to show how it may be carried into effect, certain embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0029] Figure 1 An example of a battery material recycling process is shown;

[0030] Figure 2 Another example of a battery material recycling process is shown;

[0031] Figure 3 A flow chart showing a method according to the present specification;

[0032] Figure 4 Another flow chart of the method according to the present description is shown, it being noted that the initial calcination step (oxidative heat treatment) is optional;

[0033] Figure 5 An example of parameters used to test washing with water to extract lithium and fluorine species after a reductive heat treatment is shown;

[0034] Figure 6 Shows that following Figure 5 An example of lithium distribution (deportments) in the process of;

[0035] Figure 7 Shows that following Figure 5 Another example of lithium distribution in the process of;

[0036] Figure 8 Shows that following Figure 5 An example of fluorine distribution in a process;

[0037] Fig. 9An example of parameters used to test washing with water to extract fluorine species after oxidative heat treatment (calcination) is shown;

[0038] Figure 10 shows that for the following three different oxidation atmospheres Fig. 9 Examples of fluorine distribution for processes of: (a) dry air; (b) water in air; and (c) NH4OH in air; and

[0039] Fig.11 An example of a flow chart combining calcination and reduction treatments is shown. Specific implementation plan

[0040] Figure 1 An example of a battery material recycling process is shown. The starting material is cathode waste or so-called "black powder", which typically contains lithium, nickel, cobalt, manganese and impurities including copper and iron. The material is subjected to an acid dissolution or leaching step to obtain an acidic aqueous recovery feed containing constituent metal species in solution. The acidic aqueous recovery feed also contains impurities, such as iron that may interfere with subsequent extraction steps. Therefore, before further processing the acidic aqueous recovery feed, it is desirable to selectively remove these impurities. An organic solvent extraction step can then be applied to separate cobalt and nickel (in the organic phase) from manganese and lithium. Before eluting cobalt and nickel into the cobalt and nickel aqueous solution, the organic phase can be additionally acid-washed to remove any remaining impurities. The organic phase can be regenerated and recycled for further extraction of cobalt and nickel. Figure 1 The method is able to separate cobalt and nickel from cathode black powder. However, to separate lithium and manganese from each other, additional process steps are required.

[0041] Figure 2 Another example of a battery material recycling process is shown. The starting material is also cathode waste or so-called "black powder", which typically contains lithium, nickel, cobalt, manganese and impurities including copper and iron (aluminum is usually the third major impurity). However, in this example, lithium is first removed by treating with a suitable solvent (e.g., an organic acid, such as formic acid) that dissolves lithium but does not dissolve other metal substances. The remaining material is subjected to an acid dissolution or leaching step to obtain an acidic aqueous recovery feed containing the remaining constituent metal substances in the solution. The acidic aqueous recovery feed also contains impurities, such as iron that may interfere with subsequent extraction steps. Therefore, before further processing the acidic aqueous recovery feed, it is desirable to selectively remove these impurities. An organic solvent extraction step can then be applied to separate cobalt and nickel (in the organic phase) from manganese. Before eluting cobalt and nickel into the cobalt and nickel aqueous solution, the organic phase can be further acid-washed to remove any remaining impurities. The organic phase can be regenerated and recycled for further extraction of cobalt and nickel. Figure 2 The advantage of the method is that it can achieve an efficient 4-way separation of lithium, manganese, cobalt and nickel.

[0042] For reference Figure 1 and Figure 2 Any of the battery material recycling processes described are problematic due to the presence of fluorine-containing species in the starting black powder material, which generate HF during material processing. Since HF is a serious environmental health and safety risk, it is desirable to remove the fluorine species from the black powder material prior to performing processing steps to recover valuable metal elements from the material.

[0043] This manual covers Figure 2 The battery material recycling method shown in the figure, in which lithium is extracted from the spent battery cathode material before the sulfuric acid dissolution step. As described in the "Summary of the Invention" section and Figure 3 As shown in the flow chart of the present specification, a method for recovering a waste battery cathode material containing lithium and at least one of nickel, cobalt and / or manganese is provided, the method comprising: heating the waste battery cathode material in a reducing atmosphere to form a heat-treated waste battery cathode material containing LiF and one or more of Li2O, LiOH and Li2CO3; washing the heat-treated waste battery cathode material in an aqueous solvent (e.g., water) to extract lithium-containing substances and fluorine-containing substances, wherein the aqueous solvent does not contain alkaline earth metal hydroxides or other substances intended to prevent fluorine from remaining dissolved in the aqueous solvent; separating the waste battery cathode material containing lithium and fluorine from the heat-treated waste battery material; an aqueous solvent containing lithium and fluorine substances; after separating the aqueous solvent containing lithium and fluorine substances from the heat-treated waste battery material, treating the aqueous solvent to separate the lithium substance from the fluorine substance; recovering the lithium substance in the form of lithium hydroxide or lithium carbonate; after the step of separating the aqueous solvent from the heat-treated waste battery material, forming an acidic aqueous recovery feed containing one or more of nickel, cobalt and / or manganese by leaching the heat-treated waste battery cathode material with an inorganic acid; and recovering one or more of nickel, cobalt and / or manganese from the acidic aqueous recovery feed by one or more additional process steps selected from solvent extraction, solid phase extraction, electrochemical extraction and precipitation processes.

[0044] Figure 4Another flow chart of the method according to the present specification is shown. Optionally, the black powder is first calcined, that is, it is heated in an oxidizing atmosphere. This oxidative heat treatment can be used to remove volatile organics, including volatile fluorine-containing substances (e.g., HF and volatile organic fluorine compounds). For example, the oxidative heat treatment can be used to remove volatile organic solvents (e.g., from electrolyte solutions), fluorinated electrolytes present as additives, and fluorinated degradation products present in scrapped batteries. Care should be taken to avoid decomposing insoluble fluorine-containing substances such as PVDF into soluble fluorine substances, which require more washing to remove before leaching the material with inorganic acids. Therefore, heating the waste battery cathode material in an oxidizing atmosphere can be carried out at a temperature below 400°C, for example, at a temperature of 250°C to 350°C. The oxidizing atmosphere can include additives in the oxidizing gas (e.g., air), such as water and / or NH4OH. For example, these additives can affect the amount of organic fluorine compounds formed during the oxidative heat treatment. Such additives can also affect the decomposition of PVDF, although this is not a serious problem when the temperature is maintained below 350°C.

[0045] Next, the black powder is heated in a reducing atmosphere (e.g., hydrogen or a mixture of hydrogen and an inert gas such as nitrogen). This heat treatment decomposes the spent battery cathode material to convert the lithium into a form that can be washed out of the material with an aqueous solvent. The heat treatment also volatilizes and removes a portion of the fluorine-containing substances that would otherwise be washed out during the subsequent lithium aqueous phase leaching process (e.g., LiFP6 decomposition products or volatile fluorinated electrolyte solvents, such as fluoroethylene carbonate FEC). This can reduce the amount of fluorine substances washed out during the subsequent lithium aqueous phase leaching process, thereby reducing the number of washing cycles required to remove soluble fluorine substances from the solid heat-treated spent battery cathode material. However, with respect to the calcination step, if the heat treatment is carried out at a sufficiently high temperature to result in the decomposition of insoluble fluorine components (e.g., PVDF) into soluble fluorine substances, then this may have the opposite effect, i.e., increasing the amount of soluble fluorine substances in the spent battery cathode material, thereby requiring more washing to extract all of the soluble fluorine, which would otherwise result in the formation of HF during the mineral acid leaching. Therefore, a balance can be reached,

[0046] That is, the material is heated to a temperature sufficient to release lithium in soluble form, while the temperature is not so high that the insoluble fluorine component is decomposed to release soluble fluorine. For example, the spent battery cathode material can be heated in a reducing atmosphere to a temperature of at least 200°C, 250°C, 300°C, 350°C or 400°C; not more than 600°C, 550°C, 500°C, 450°C, 400°C, 350°C, 300°C or 250°C; or a temperature within the range defined by any combination of the above lower and upper limits. The heating can be carried out for at least 5 minutes, 10 minutes, 20 minutes or 30 minutes; not more than 3 hours, 2 hours or 1 hour; or a time within the range defined by any combination of the above lower and upper limits. The reducing atmosphere can contain at least 2%, 3%, 4% or 5%; not more than 100%, 50%, 30%, 20% or 10%; or a volume percentage of hydrogen within the range defined by any combination of the above lower and upper limits. The reducing atmosphere may contain nitrogen as an inert gas in which hydrogen is present. Thus, the reducing atmosphere may contain hydrogen or a mixture of nitrogen and hydrogen, or may consist essentially of hydrogen or a mixture of nitrogen and hydrogen.

[0047] It has also been found that a small portion of lithium is lost during the thermal treatment. It is believed that this is at least partially due to a reaction with the container in which the material is placed during the thermal treatment. Therefore, it is advantageous that the thermal treatment (reduction thermal treatment, or optionally also oxidation calcination) is carried out in a container formed by one or more of nickel, nickel alloy, graphite, silicon carbide, dense alumina ceramic or mullite porcelain or a container lined with such material. This can help reduce lithium losses during the thermal treatment.

[0048] Next, the black powder is washed with water to extract lithium and remaining soluble fluorine species from the solid material while leaving nickel, cobalt and manganese species in the solid black powder. The purpose of this is to extract lithium and soluble fluorine species before the subsequent acid dissolution step. The soluble fluoride and lithium are extracted into an aqueous leachate containing LiOH, Li2CO3 and LiF. The solubility of LiF is lower than the solubility of Li2O (which is hydrolyzed to LiOH during washing), LiOH and Li2CO3. Therefore, although the first washing cycle can extract substantially all of the Li2O, LiOH and Li2CO3, in order to ensure that substantially all of the LiF is also extracted, it may be advantageous to subject the thermally treated spent battery cathode material to one or more additional washings in an aqueous solvent, the aqueous solvent produced by the one or more additional washings containing at least LiF, but if residual amounts of LiOH and Li2CO3 are left in the solid material after the first washing cycle, these one or more subsequent washings may also release small amounts of LiOH and Li2CO3.

[0049] The remaining solid black powder can then be subjected to mineral acid dissolution in sulfuric acid (optionally with hydrogen peroxide) to extract nickel, cobalt and manganese materials into the acid recovery feed. Then known methods are used to perform an impurity removal process, as well as separation and purification of nickel, cobalt and manganese. A key feature is that the acid recovery feed is substantially free of HF or fluorine materials that form HF, otherwise these materials can cause harm to health and safety and damage to processing equipment. The process of the present invention removes soluble HF forming materials during the initial lithium removal, so that the solid waste can be acid-dissolved without the need for other processing steps. For example, after heating the solid waste as described herein and washing to extract lithium and fluorine, nickel, cobalt and / or manganese can be leached into the acidic aqueous recovery feed without the need to subject the solid waste to other processing / separation steps after lithium extraction and before acid dissolution.

[0050] The soluble fluoride and lithium extracted in the previous water wash can be further processed to separate the lithium and fluorine species and recover the lithium. For example, by adding Ca(OH)2, LiF can be converted into soluble LiOH and insoluble CaF2. The CaF2 can then be removed by solid-liquid separation, followed by recovery of the lithium in the form of LiOH by crystallization, or by adding CO2 to recover the lithium in the form of Li2CO3. Alternatively, different alkaline earth metal hydroxides can be used to separate the fluorine species from the lithium species.

[0051] As an alternative to using alkaline earth metal hydroxides to precipitate fluoride, other reactants may be used to precipitate fluoride species, thereby separating fluoride and lithium species using a solid-liquid separation process. Examples of fluoride precipitation reactants include chlorides, hydroxides, carbonates, bicarbonates, acetates, formates of alkali and alkaline earth metals, and mixtures of two or more of these reactants. For example, a combination of CaCl2 and Ca(OH)2 or NaOH and CaCl2 may be used in the fluoride precipitation process. Other examples include calcium chloride, calcium bicarbonate, calcium acetate, and calcium formate. In this regard, it is also noted that the solubility of calcium hydroxide is relatively poor and is therefore not preferred for precipitating large amounts of CaF2. The use of calcium salts with better solubility allows for better control of the Ca in solution. 2+ concentration to precipitate a large amount of CaF2.

[0052] As an alternative to using one or more of the above reactants to precipitate fluorine, a solid phase extractor (SPE) can be used to extract fluorine from an aqueous solvent containing fluorine and lithium species. The SPE can be a silica-based adsorbent, a metal-based adsorbent, and / or an ion exchange resin that can adsorb / react with fluorine. Examples of ion exchange resins include amino-methylphosphonic acid functionalized chelating resins preloaded with zirconium or aluminum, strongly basic anion exchange resins containing quaternary ammonium functional groups, preloaded with metal ions (e.g., Fe 3+ 、Al3+ 、Ce 3+ and / or La 3+ ) or cryptands. Preferably, the SPE is a silica-based adsorbent, such as a glass material, such as a barium silicate glass material which can be provided in the form of a glass powder. The fluorine-containing wash solution can be passed through a packed column or bed with such an adsorbent to remove fluorine. The adsorbent can be periodically replaced and / or treated to remove fluorine and regenerated for reuse.

[0053] Alternatively, other types of separation methods may be used to extract and purify lithium from the wash solution, for example, electrochemical separation using a cation exchange membrane to extract Li + ions and subsequently recover lithium in the form of LiOH or Li2CO3.

[0054] Figure 5 An example of parameters used to test water washing after a reduction heat treatment to extract lithium and fluorine species is shown. A sample of spent battery cathode material was heat treated at 500°C for 4 hours under an atmosphere of 5% hydrogen in nitrogen. The heat treated material was then water washed: 10 grams of solid material per liter of water for 2 hours. Lithium measurements were made using inductively coupled plasma spectroscopy and lithium mass balance calculations were performed.

[0055] Figure 6 Shows that following Figure 5 An example of the lithium distribution of a process of FIG. 1 is shown. In this example, the feed was a mixture comprising approximately 60 wt% NMC 622 and 40 wt% graphite. Mass balance calculations indicate that 91% of the lithium is recovered in the water wash, 9% of the lithium is lost during heat treatment, and 3% of the lithium remains in the solid wash residue. The lithium losses in the heat treatment are likely to be, at least in part, experimental error. However, there may be small amounts of lithium lost during the heat treatment due to reactions with the alumina crucibles used for testing, which may be reduced by selecting an alternative crucible, such as a crucible formed from or lined with one or more of nickel, nickel alloys, graphite, silicon carbide, dense alumina ceramic, or mullite ceramic. The remaining 3% lithium in the solids may also be an experimental error, but if there is any remaining lithium in the solids then this may be extracted by further downstream processing of the solid material. It should also be noted that Figure 6 The -3% error shown in means that the mass balance when all the distributed components are compared to the lithium in the feed totals 103%. Therefore, we have overestimated the individual distributed components by a total of 3%.

[0056] Figure 7 Shows that following Figure 5Another example of lithium distribution for a process of . In this example, the feed is a commercially available black powder sample. Mass balance calculations indicate that 75% of the lithium is recovered in the water wash, 15% of the lithium is lost during heat treatment, and 19% of the lithium remains in the solid wash residue. As in the previous example, the lithium losses in the heat treatment are likely to be at least partially experimental error. However, there may be small amounts of lithium lost during the heat treatment due to reactions with the alumina crucibles used for testing, which may be reduced by selecting an alternative crucible, such as a crucible formed from or lined with one or more of nickel, nickel alloys, graphite, silicon carbide, dense alumina ceramic, or mullite ceramic. The remaining 19% of lithium in the solids may also be at least partially experimental error, but if there is any remaining lithium in the solids then this may be extracted by further downstream processing of the solid material. It should also be noted that Figure 7 The -9% error shown in means that the mass balance when all the distributed components are compared to the lithium in the feed totals 109%. Therefore, we have overestimated the individual distributed components by a total of 9%.

[0057] In addition to the measurement / calculation of lithium, a fluorine mass balance was calculated based on combustion ion chromatography measurements (IC-AQF). Figure 8 The feed containing NMC 622 and PVDF follows Figure 5 An example of the fluorine distribution for a process of . The figure shows that about 54% of the fluorine is volatilized in the thermal treatment (as volatile organic fluorine compounds and HF gas) and about 27% is washed out in the water wash. 2% remains in the solid residue, but this is within the experimental error. Removing fluorine from the feed in this way means that the solid residue after the water wash is more suitable for dissolution by inorganic acids without the generation of HF.

[0058] Fig. 9 An example of parameters used to test washing with water after oxidative heat treatment (calcination) to extract fluorine species is shown. The feeds used in these tests included NMC 622 and PVDF. In these experiments, calcination was carried out at 500°C for 3 hours under three different oxidizing atmospheres: dry air; H2O in air; and NH4OH in air. The heat treated material was then washed in water for 2 hours with 10 grams of solid material per liter of water. Figure 10 shows the parameters of the three different oxidizing atmospheres followed by Fig. 9Examples of fluorine distribution for processes: (a) dry air; (b) H2O in air; and (c) NH4OH in air. In each case, about 50% of the fluorine is volatilized during the thermal treatment and about 50% of the fluorine is washed out during the water wash. However, different atmospheres change the ratio of volatile organic fluorine compounds (CF) and HF gases emitted during the thermal treatment. Experiments have shown that if PVDF decomposes (intentionally or accidentally), then additives such as NH4OH appear to reduce the content of organic fluorine compounds. Although these oxidation tests were conducted at 500°C, in practice, if the spent battery cathode material contains a large amount of insoluble fluorine-containing species, such as PVDF, then it may be desirable to remove the volatile organics and fluorine species before washing without degrading the PVDF into large amounts of soluble fluorine species. Therefore, one approach is to use a flow chart that combines calcination and reduction treatments, such as Fig.11 As shown. In this method, the wet chopped black powder is subjected to an oxidation treatment (e.g., at 200-300°C) and then a reduction treatment (e.g., at 200-500°C, optionally below 300°C). The heat-treated material is then washed with water to extract lithium and fluorine species before dissolution with an inorganic acid. Other steps are as described above for treating the wash fluid to recover lithium and treating the acidic recovery feed to recover cobalt, nickel and manganese.

[0059] As indicated above, for some applications, oxidation treatment may not be required. Alternatively, oxidation treatment may be performed after reduction treatment and washing. In other words, the process may include the following steps: (i) reduction heat treatment of black powder; (ii) washing / leaching of lithium / fluorine; (iii) oxidation heat treatment of black powder; and (iv) acid dissolution of black powder. The exact optimized parameters of the heat treatment will vary depending on the variability of the initial spent battery cathode feed. In general, advantageously, the source material is in powder form, for example, a powder having a maximum particle size of less than 1 mm. Such a powder material may be formed by grinding the source material before heat treatment. It is easier to extract fluorine and lithium from such a small particle size source material than from a source material containing larger pieces / chunks of solid material in which fluorine and / or lithium species may be entrained within the material. The source material may be battery waste, such as black powder battery waste derived from a battery cathode material containing lithium and at least one of nickel, cobalt and / or manganese. In this case, the black powder may be ground to a small particle size before heat treatment.

[0060] As used herein, the term "include" means "comprising". Variations of the word "include" have correspondingly varying meanings. As used herein, the terms "include" and "include" are non-exclusive. As used herein, the terms "include" and "include" do not imply that the specified integer represents a major portion of the whole.

[0061] Where applicants define an invention or a portion of an invention using open-ended terms such as "comprising", it is readily understood that (unless otherwise stated) the description should be interpreted as also using the terms "consisting essentially of" or "consisting essentially of" to describe such an invention. In other words, with respect to the terms "comprising", "consisting essentially of", and "consisting essentially of", when one of these three terms is used herein, the subject matter disclosed and claimed herein may include the use of any of the other two terms. Thus, in some embodiments not explicitly recited, any instance of "comprising" may be replaced with "consisting essentially of" or "consisting essentially of".

[0062] The transitional phrase "consisting of" excludes any unspecified element, step, or ingredient. If in a claim, this would cause the claim to contain only the recited materials, except for the impurities normally associated therewith. When the phrase "consisting of" appears in a clause in the body of a claim rather than immediately following the preamble, it limits only the elements listed in that clause; it does not exclude other elements in the claim as a whole.

[0063] The transitional phrase "consisting essentially of" is used to qualify compositions, processes, or methods that include additional materials, steps, features, components, or elements in addition to the materials, steps, features, components, or elements literally disclosed, provided that such additional materials, steps, features, components, or elements do not materially affect the basic and novel characteristics of the claimed invention. The term "consisting essentially of" is intermediate between "comprising" and "consisting of."

[0064] In addition, unless expressly stated otherwise, "or" refers to an inclusive rather than an exclusive or. For example, any of the following satisfies condition A or B: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0065] In addition, the indefinite articles "a" and "an" before the elements or components of the present invention are not intended to limit the number of instances of the elements or components (i.e., the number of occurrences). Therefore, "a" or "an" should be understood to include one or at least one, and the singular form of the elements or components also includes the plural form, unless the number obviously means the singular.

[0066] Except in the operating examples or as otherwise indicated, all numerals used herein to represent the quantity of ingredients or reaction conditions are to be understood as being modified in all cases by the term "about". These examples are not intended to limit the scope of the invention. Except as otherwise indicated herein, "%" or "wt%" will mean "% by weight".

[0067] Unless otherwise defined, the terms "mainly" and "substantially" as used herein mean comprising greater than 50% by weight.

[0068] Unless otherwise limited, the terms "about," "approximately," and "substantially" as used herein with respect to numbers within a numerical range should be understood to refer to a range of -10% to +10% of the number being addressed, preferably -5% to +5% of the number being addressed, more preferably -1% to +1% of the number being addressed, and most preferably -0.1% to +0.1% of the number being addressed. In addition, with respect to numerical ranges, these terms should be interpreted as providing support for claims directed to any number or subset of numbers within the range. For example, a disclosure of 1 to 10 should be interpreted as supporting ranges of 1 to 8, 3 to 7, 1 to 9, 3.6 to 4.6, 3.5 to 9.9, 8 to 10, etc.

[0069] As used herein, wt % refers to the weight of a particular component relative to the total weight of the referenced composition.

[0070] The entire disclosures of the patents, patent documents, and publications cited herein are incorporated by reference in their entirety, as if each were individually incorporated.

[0071] The forms of the present invention include:

[0072] 1. A method for recovering spent battery cathode material containing lithium and at least one of nickel, cobalt and / or manganese, the method comprising:

[0073] Heating the spent battery cathode material in a reducing atmosphere to form a heat-treated spent battery cathode material comprising LiF and one or more of Li2O, LiOH and Li2CO3;

[0074] Washing the thermally treated spent battery cathode material in an aqueous solvent to extract lithium-containing species and fluorine-containing species, wherein the aqueous solvent does not contain alkaline earth metal hydroxides or other substances intended to reduce or prevent soluble fluorine species from remaining dissolved in the aqueous solvent;

[0075] separating an aqueous solvent containing lithium and fluorine species from the thermally treated spent battery material;

[0076] After separating the aqueous solvent containing lithium and fluorine species from the thermally treated waste battery material, treating the aqueous solvent to separate the lithium species from the fluorine species;

[0077] Recovering lithium material in the form of lithium hydroxide or lithium carbonate;

[0078] forming an acidic aqueous recovery feed comprising one or more of nickel, cobalt and / or manganese by leaching the thermally treated spent battery cathode material with a mineral acid after the step of separating the aqueous solvent from the thermally treated spent battery material; and

[0079] One or more of nickel, cobalt and / or manganese are recovered from the acidic aqueous recovery feed by an additional process step selected from one or more of solvent extraction, solid phase extraction, electrochemical extraction and precipitation processes.

[0080] 2. The method according to form 1,

[0081] After the heat-treated waste battery cathode material is washed in an aqueous solvent, the aqueous solvent contains LiF, and one or two of LiOH and Li2CO3.

[0082] 3. The method according to form 1 or 2,

[0083] After washing the heat-treated waste battery cathode material in an aqueous solvent, the heat-treated waste battery cathode material is subjected to one or more additional washings in an aqueous solvent, and the aqueous solvent produced by the one or more additional washings contains at least LiF.

[0084] 4. A method according to any of the preceding forms,

[0085] The step of treating the aqueous solvent to separate the lithium species from the fluorine species includes adding a precipitation reactant to precipitate the fluorine species in the form of fluoride, and then separating the fluoride from the aqueous solvent by a solid-liquid separation process.

[0086] 5. The method according to form 4,

[0087] The precipitation reactant is selected from the group consisting of hydroxides, chlorides, hydroxides, carbonates, bicarbonates, acetates, formates of alkali metals and alkaline earth metals, and mixtures of two or more of these reactants.

[0088] 6. A method according to any one of forms 1 to 3,

[0089] Wherein the step of treating the aqueous solvent to separate the lithium species from the fluorine species comprises adsorbing the fluorine onto a solid phase extractant.

[0090] 7. The method according to form 6,

[0091] The solid phase extractant is one or more of a silica-based adsorbent, a metal-based adsorbent, a solid phase support medium functionalized with basic anion exchange groups, and a solid phase support medium functionalized with a chelating ligand optionally preloaded with metal ions.

[0092] 8. The method according to form 7,

[0093] The adsorbent is barium silicate glass material.

[0094] 9. A method according to any preceding form,

[0095] Wherein the spent battery cathode material is heated in a reducing atmosphere to a temperature of at least 200°C, 250°C, 300°C, 350°C or 400°C; not more than 600°C, 550°C, 500°C, 450°C, 400°C, 350°C, 300°C or 250°C; or a temperature within a range defined by any combination of the above lower limit and upper limit values.

[0096] 10. A method according to any preceding form,

[0097] The reducing atmosphere is hydrogen or hydrogen in an inert gas, and the inert gas is optionally nitrogen.

[0098] 11. A method according to any preceding form,

[0099] The spent battery cathode material is heated in a reducing atmosphere for at least 5 minutes, 10 minutes, 20 minutes or 30 minutes; not more than 3 hours, 2 hours or 1 hour; or a time within a range defined by any combination of the above lower and upper limits.

[0100] 12. A method according to any preceding form,

[0101] The heating of the waste battery cathode material in a reducing atmosphere is carried out in a container, which is formed by one or more of nickel, nickel alloy, graphite, silicon carbide, alumina ceramic or mullite porcelain, or is lined with one or more of nickel, nickel alloy, graphite, silicon carbide, alumina ceramic or mullite porcelain.

[0102] 13. A method according to any preceding form,

[0103] The method further comprises heating the spent battery cathode material in an oxidizing atmosphere before or after heating the spent battery cathode material in a reducing atmosphere.

[0104] 14. The method according to form 13,

[0105] The heating of the spent battery cathode material is carried out at a temperature below 400° C. in an oxidizing atmosphere.

[0106] While the invention has been particularly shown and described with reference to certain embodiments, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention as defined in the following claims.

Claims

1. A method for recovering spent battery cathode material containing lithium and at least one of nickel, cobalt and / or manganese, the method comprising: Heating the spent battery cathode material in a reducing atmosphere to form a heat-treated spent battery cathode material comprising LiF and one or more of Li2O, LiOH, and Li2CO3; washing the thermally treated spent battery cathode material in an aqueous solvent to extract lithium-containing species and fluorine-containing species, wherein the aqueous solvent does not contain alkaline earth metal hydroxides or other substances intended to reduce or prevent soluble fluorine species from remaining dissolved in the aqueous solvent; separating the aqueous solvent containing lithium and fluorine species from the thermally treated spent battery material; after separating the aqueous solvent containing lithium and fluorine species from the thermally treated waste battery material, treating the aqueous solvent to separate the lithium species from the fluorine species; Recovering the lithium substance in the form of lithium hydroxide or lithium carbonate; forming an acidic aqueous recovery feed comprising one or more of nickel, cobalt and / or manganese by leaching the thermally treated spent battery cathode material with a mineral acid after the step of separating the aqueous solvent from the thermally treated spent battery material; and One or more of nickel, cobalt and / or manganese are recovered from the acidic aqueous recovery feed by an additional process step selected from one or more of solvent extraction, solid phase extraction, electrochemical extraction and precipitation processes.

2. The method according to claim 1, After washing the heat-treated waste battery cathode material in the aqueous solvent, the aqueous solvent contains LiF, and one or two of LiOH and Li2CO3.

3. The method according to claim 1 or 2, After washing the heat-treated waste battery cathode material in the aqueous solvent, the heat-treated waste battery cathode material is subjected to one or more additional washings in the aqueous solvent, and the aqueous solvent produced by the one or more additional washings contains at least LiF.

4. The method according to any one of the preceding claims, The step of treating the aqueous solvent to separate the lithium species from the fluorine species includes adding a precipitation reactant so that the fluorine species precipitates in the form of fluoride, and then separating the fluoride from the aqueous solvent through a solid-liquid separation process.

5. The method according to claim 4, The precipitation reactant is selected from the group consisting of hydroxides, chlorides, hydroxides, carbonates, bicarbonates, acetates, formates of alkali metals and alkaline earth metals, and mixtures of two or more of these reactants.

6. The method according to any one of claims 1 to 3, Wherein the step of treating the aqueous solvent to separate the lithium species from the fluorine species comprises adsorbing the fluorine onto a solid phase extractant.

7. The method according to claim 6, The solid phase extractant is one or more of a silica-based adsorbent, a metal-based adsorbent, a solid support medium functionalized with basic anion exchange groups, and a solid support medium functionalized with a chelating ligand optionally preloaded with metal ions.

8. The method according to claim 7, The adsorbent is a barium silicate glass material.

9. The method according to any one of the preceding claims, wherein the spent battery cathode material is heated in the reducing atmosphere to at least 200°C, 250°C, 300°C, 350°C or 400°C; not more than 600°C, 550°C, 500°C, 450°C, 400°C, 350°C, 300°C or 250°C; or a temperature within the range defined by any combination of the above lower limit and upper limit values.

10. The method according to any one of the preceding claims, The reducing atmosphere is hydrogen or hydrogen in an inert gas, and the inert gas is optionally nitrogen.

11. The method according to any one of the preceding claims, The spent battery cathode material is heated in the reducing atmosphere for at least 5 minutes, 10 minutes, 20 minutes or 30 minutes; not more than 3 hours, 2 hours or 1 hour; or for a time within the range defined by any combination of the above lower and upper limits.

12. The method according to any one of the preceding claims, The heating of the waste battery cathode material in the reducing atmosphere is carried out in a container, which is formed by one or more of nickel, nickel alloy, graphite, silicon carbide, alumina ceramic or mullite porcelain, or is lined with one or more of nickel, nickel alloy, graphite, silicon carbide, alumina ceramic or mullite porcelain.

13. The method according to any one of the preceding claims, The method further comprises heating the spent battery cathode material in an oxidizing atmosphere before or after heating the spent battery cathode material in the reducing atmosphere.

14. The method according to claim 13, The heating of the spent battery cathode material in the oxidizing atmosphere is performed at a temperature below 400°C.

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