Electrochemical production of alkali metal hydroxides and sulfuric acid from battery manufacturing and recovery outlet streams

Abstract

A method of producing sodium hydroxide (NaOH) or lithium hydroxide (LiOH) and sulfuric acid (H2SO4) includes generating sodium sulfate (Na2SO4) or lithium sulfate (Li2SO4) from battery manufacture and recovery and converting the generated Na2SO4 or Li2SO4 to NaOH, LiOH and H2SO4 by an electrochemical salt decomposition process. The treatment step may be performed in a closed system such that the generated Na2SO4 or Li2SO4 may be used during the conversion process, and optionally a purification step. In particular, LiOH, NaOH, and Na2SO4 are recovered to a battery recovery or battery manufacturing process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 409,167, filed on September 22, 2022. The above application is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates generally to chemical manufacturing and recovery, and in particular to the production of alkali metal hydroxide and sulfuric acid from battery manufacturing and recovery outlet streams. Background Art

[0004] Sodium hydroxide (NaOH), lithium hydroxide (LiOH), and sulfuric acid (H2SO4) are important commodity chemicals that are widely used in chemical, pharmaceutical, energy, paper and pulp, and water industries, etc. For example, NaOH is widely used in the manufacture of other chemicals due to its alkalinity, LiOH is used to produce cathode active materials for battery applications, and H2SO4 is used in large quantities to manufacture phosphate fertilizers.

[0005] Existing technologies for producing NaOH, LiOH, and H2SO4 are either complex processes or produce other chemicals that are hazardous. For example, high-purity NaOH is primarily produced from brine using a chlor-alkali process that produces dangerous chlorine gas (Cl2). In some cases, the production of LiOH may involve the extraction and purification of lithium carbonate (Li2CO3) from chloride-containing lithium minerals. For example, lithium chloride (LiCl) can be converted to Li2CO3 using sodium carbonate (Na2CO3), and then Li2CO3 can be further converted to LiOH using calcium hydroxide (Ca(OH)2), all starting from salty brine. In other cases, LiOH can be produced by converting lithium sulfate (Li2SO4) generated from minerals into LiOH using NaOH. Finally, the production of H2SO4 can consist of multiple steps, including the extraction of sulfur and its conversion into sulfur dioxide (SO2) through refining technology, the high-temperature catalytic conversion of SO2 into sulfur trioxide (SO3), and the subsequent conversion of SO3 into H2SO4 using water. Summary of the invention

[0006] One or more embodiments of the present disclosure include systems and methods for generating one or more of NaOH, LiOH, or H2SO4 by electrochemical salt-splitting. For example, one or more embodiments include utilizing an outlet stream from a lithium-ion battery manufacturing or recycling process to generate sodium cations (Na + ) or lithium cation (Li + ) and sulfate anions (SO4 2-This embodiment performs electrochemical salt decomposition to generate sodium cations (Na + ) or lithium cation (Li + ) and sulfate anions (SO4 2- ) to prepare one or more of NaOH, LiOH or H2SO4.

[0007] For example, in one or more embodiments, the method includes generating Na2SO4 from a battery manufacturing process. The method also involves converting the generated Na2SO4 into NaOH and H2SO4 through an electrochemical salt decomposition process. For example, the method involves electrochemical salt decomposition of Na2SO4 using an electrochemical cell including two or more compartments separated by one or more ion exchange membranes. In addition, the method optionally includes converting the generated Na2SO4 into NaOH and H2SO4 without the need for one or more purification techniques required by conventional industrial methods.

[0008] In another embodiment, the method includes generating Li2SO4 from a battery recovery process. The method also involves converting the generated Li2SO4 into LiOH and H2SO4 by an electrochemical salt decomposition process. For example, the method involves electrochemical salt decomposition of Li2SO4 using an electrochemical cell including two or more compartments separated by one or more ion exchange membranes. In addition, the method optionally includes converting the generated Li2SO4 into LiOH and H2SO4 without the need for one or more purification techniques required by conventional industrial methods.

[0009] Additional features and advantages of one or more embodiments of the disclosure are outlined in the description which follows, and in part may be determined from the description, or may be learned by practicing the exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure will describe one or more embodiments of the present invention in a more specific and detailed manner by referring to the accompanying drawings. The following paragraphs briefly introduce these drawings, in which:

[0011] Figure 1 A process flow diagram for generating sodium sulfate (Na2SO4) from a battery manufacturing process according to one or more embodiments is shown.

[0012] Figure 2 A process flow diagram is shown for converting Na2SO4 into sodium hydroxide (NaOH) and sulfuric acid (H2SO4) through an electrochemical salt decomposition process according to one or more embodiments.

[0013] Figure 3 A process flow diagram for generating lithium sulfate (Li2SO4) from a battery recycling process according to one or more embodiments is shown.

[0014] Figure 4 A process flow diagram is shown for converting Li2SO4 into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) via an electrochemical salt decomposition process according to one or more embodiments.

[0015] Figure 5 The conversion of Na2SO4 into NaOH and H2SO4 through a salt decomposition process using a dual compartment electrolysis cell and a triple compartment electrolysis cell according to one or more embodiments is shown.

[0016] Figure 6 The conversion of Li2SO4 into LiOH and H2SO4 through a salt decomposition process using a dual compartment electrolysis cell and a triple compartment electrolysis cell according to one or more embodiments is shown.

[0017] Figure 7 The conversion of Li2SO4 into LiOH and H2SO4 through a salt decomposition process using a three-compartment bipolar membrane electrodialysis cell is shown according to one or more embodiments.

[0018] Figure 8 The conversion of Na2SO4 into NaOH and H2SO4 through a salt splitting process using a three-compartment bipolar membrane electrodialysis cell is shown according to one or more embodiments.

[0019] Fig. 9 and Fig.10 A bipolar membrane electrodialysis cell using a dual compartment is shown to convert Li2SO4 into LiOH and H2SO4 through a salt decomposition process according to one or more embodiments.

[0020] Fig.11 A flow chart is shown of a series of operations for generating Na2SO4 from battery manufacturing and converting it to NaOH and H2SO4 through an electrochemical salt decomposition process according to one or more embodiments.

[0021] Fig.12 A flow chart showing a series of operations for generating Li2SO4 from battery recycling and converting it to LiOH and H2SO4 through an electrochemical salt decomposition process according to one or more embodiments. DETAILED DESCRIPTION

[0022] The present disclosure describes one or more embodiments of methods and systems for generating Na2SO4 and Li2SO4 from a battery manufacturing process and a battery recycling process, respectively, and converting Na2SO4 and Li2SO4 into NaOH and LiOH, respectively, combined with H2SO4. For example, in some embodiments, the systems and methods of the present disclosure use an electrochemical cell having two or more compartments separated by one or more ion exchange membranes to electrochemically separate Na2SO4 or Li2SO4 outlet streams from battery manufacturing and recovery in aqueous solution to generate NaOH or LiOH combined with H2SO4. The ion exchange membrane may allow alkali metal cations or SO4 to be converted into NaOH and LiOH, respectively. 2- transported to the corresponding individual compartments. In one or more embodiments, the electrochemical salt decomposition process comprises electrolysis with an oxygen depolarized cathode, electrolysis with a hydrogen depolarized anode, electrolysis with a dimensionally stable anode, or bipolar membrane electrodialysis.

[0023] In one or more embodiments, the system utilizes electrolysis or bipolar membrane electrodialysis to perform these salt decomposition processes. In addition, in one or more embodiments, the electrochemical salt decomposition process for converting Na2SO4 or Li2SO4 into NaOH or LiOH combined with H2SO4, respectively, can include bipolar membrane electrodialysis. In electrolysis, the anode and cathode reactions can produce protons (H + ) and hydroxide (OH - ), therefore, H2SO4 and NaOH or H2SO4 and LiOH can be produced and accumulated in the anolyte and catholyte, respectively. In bipolar membrane electrodialysis, the bipolar ion exchange membrane is H + and OH - is the main generator, rather than the anode and cathode reactions.

[0024] For example, in one or more embodiments, the method includes generating Na2SO4 from a battery manufacturing process. The method also involves converting the generated Na2SO4 into NaOH and H2SO4 through an electrochemical salt decomposition process. For example, the method involves electrochemical salt decomposition of Na2SO4 using an electrochemical cell having two or more compartments separated by one or more ion exchange membranes.

[0025] In one or more embodiments, the method involves generating Na2SO4 in a closed system and converting the generated Na2SO4 into NaOH and H2SO4. In other words, once Na2SO4 is generated from an outlet stream of a battery manufacturing process, the method involves introducing the outlet stream in situ (e.g., locally or on-site) into an electrochemical cell for use in a salt decomposition process within a closed-loop system (e.g., an integrated plant including battery material manufacturing and electrolytic recycling). Some embodiments involve reintroducing the resulting products of the electrochemical salt decomposition process, i.e., NaOH and H2SO4, into the battery manufacturing and recycling process.

[0026] In addition, some embodiments involve performing the conversion of Na2SO4 to NaOH and H2SO4 to manage the upstream concentration and purity in the synthesis of the precursor cathode active material (pCAM). Additionally or alternatively, the method includes utilizing high purity water to manage impurities. By managing inputs and impurities, the system can eliminate one or more purification steps required by most industrial electrochemical salt decomposition technologies, as discussed in further detail below.

[0027] In another embodiment, the method includes generating Li2SO4 from a battery recovery process. The method also involves converting the generated Li2SO4 into LiOH and H2SO4 by an electrochemical salt decomposition process. For example, the method involves electrochemical salt decomposition of Li2SO4 using an electrochemical cell having two or more compartments separated by one or more ion exchange membranes.

[0028] In addition, some embodiments involve generating Li2SO4 in a closed or closed-loop system and converting the generated Li2SO4 into LiOH and H2SO4. In other words, once Li2SO4 is generated from the outlet stream of the battery recycling process, the method involves introducing the outlet stream into an electrochemical cell in situ (e.g., locally or on-site) within the closed or closed-loop system for use in a salt decomposition process. Similarly, some embodiments involve reintroducing the resulting products (i.e., LiOH and H2SO4) into the battery manufacturing and recycling process. In addition, one or more embodiments may include controlling the concentration and purity of the inputs in the process of recycling battery materials during the battery recycling process, which can omit or simplify downstream purification and processing steps when converting Li2SO4 to LiOH and H2SO4.

[0029] Electrochemical salt decomposition of alkali metal sulfates has recently attracted interest as a modular platform to produce their constituent hydroxides and acids. However, technical challenges are posed by the presence of impurities in battery manufacturing and recycling streams that can contaminate anodes, cathodes, and membranes, leading to increased cell resistance, loss of current efficiency, and increased downtime to replace these components, resulting in higher costs and lower productivity. Additionally, there are technical challenges in producing contaminated acid streams because contaminated acids are not commercially replaceable products.

[0030] In practice, conventional industrial techniques typically require multiple purification steps, including: (1) starting with a NaCl or brine solution, (2) dissolving or formulating the solution into a concentrated brine, (3) removing any organic matter or solid particles (e.g., microorganisms, algae, dust) in the brine by ultrafiltration, (4) removing initial hardness by carbonation using CO2 or soda, caustic soda (NaOH), CaCl2, Ba(OH)2, which can remove Ca, Mg, and SO4, (5) filtering and removing solid precipitates, typically through candle filters or other filtration methods, (6) IX purification step to further remove Ca, Mg, (7) evaporation to concentrate the brine to near saturation; and (8) pH adjustment to the target pH (pH = 7).

[0031] Additionally, interest in the electrochemical salt decomposition of sodium sulfate (Na2SO4) (as well as lithium sulfate (Li2SO4)) stems from recent macro trends that have led to challenges in handling or selling Na2SO4, including, but not limited to, the rapid expansion of the battery industry due to the popularity of electric vehicles (EVs), thereby increasing the production of Na2SO4, the global shift away from powdered detergents (the largest end market for Na2SO4), and increased global oversight of restrictions on the dumping of Na2SO4 into rivers, lakes and oceans and the environmental impacts / regulations of cross-border sales of Na2SO4.

[0032] As described in more detail below, the advantages of the disclosed systems and methods include, for example, but not limited to, eliminating one or more purification steps to remove unwanted metal impurities from the Na2SO4 or Li2SO4 outlet streams of cell manufacturing and recycling required for industrial electrochemical salt decomposition technology. In addition, when these outlet streams are highly concentrated with Na2SO4 and Li2SO4, the disclosed system provides improved productivity and intensifies the process by electrochemically co-producing NaOH or LiOH with H2SO4.

[0033] More specifically, in some embodiments, the method of generating Na2SO4 can include controlling the concentration and purity of inputs in the synthesis of the precursor cathode active material (pCAM), which can save some purification steps when converting Na2SO4 to NaOH and H2SO4. Similarly, one or more embodiments can include controlling the concentration and purity of inputs in the process of recycling battery materials during battery recycling, which can save or simplify downstream purification and processing steps when converting Li2SO4 to LiOH and H2SO4.

[0034] Similarly, in some embodiments, the method of generating Li2SO4 and converting Li2SO4 into LiOH and H2SO4 can include controlling the concentration and purity of the inputs in the process of recycling battery materials during the battery recycling process, such as by controlling the raw materials and reagents used. In addition, in some embodiments, the method can include controlling impurities by utilizing high purity water. In fact, by controlling the inputs and impurities, the system can save some purification steps (such as crystallization techniques) and simplify the process to save capital and operating expenses and simplify the process, as described in more detail below.

[0035] Reference Figure 1 , which shows a process flow diagram for generating sodium sulfate (Na2SO4) from a battery manufacturing process 100 according to one or more embodiments. In one or more embodiments, the battery manufacturing process 100 can generate Na2SO4 as a byproduct from the synthesis of a precursor cathode active material (pCAM). For example, in one embodiment, the battery manufacturing process 100 includes synthesizing a metal hydroxide (M(OH)2), also referred to as pCAM, using a pCAM reactor 102. In some embodiments, the battery manufacturing process 100 can react a metal sulfate (M(SO)4) (which can be a single metal sulfate (e.g., NiSO4, CoSO4, MnSO4) or a mixture of metal sulfates) with sodium hydroxide (NaOH) in the presence of ammonium hydroxide (NH4OH). In this or other embodiments, the battery manufacturing process 100 can use NaOH as a precipitant while using NH4OH as a chelating agent to control the precipitation reaction. The entire precipitation reaction can be shown as shown in the following equation (1).

[0036] M(SO4) (aq) + 2NaOH (aq) → M(OH)2 (s) + Na2SO4 (aq) (1)

[0037] In some embodiments, as shown in equation (1), the battery manufacturing process 100 can precipitate M(OH)2 solids while producing Na2SO4 as a byproduct. In one or more embodiments, the battery manufacturing process 100 can pass the aqueous byproduct stream containing Na2SO4 through an ammonia recovery process 104 to remove valuable ammonia (NH3) as NH4OH solution, which the battery manufacturing process 100 can then recycle back to the factory for pCAM production. In some embodiments, the battery manufacturing process 100 can produce a Na2SO4 solution 106 having specifications as shown in Table 1 after ammonia recovery 104.

[0038] Table 1. Composition of sodium sulfate solution

[0039]

[0040]

[0041] Although the Na 2 SO 4 solution 106 may have the composition shown above, those skilled in the art will appreciate that the Na 2 SO 4 solution 106 may have other compositions or concentrations, depending on the processing steps.

[0042] In some embodiments, the battery manufacturing process 100 can generate a Na2SO4 solution 106 having a low contaminant concentration from the battery manufacturing process 100. In fact, the battery manufacturing process 100 can generate a Na2SO4 solution 106, wherein the concentration of at least some of the contaminants in the Na2SO4 solution 106 is less than 20 ppm (20 parts per million). The generated Na2SO4 solution 106 may include various contaminants in the form of aqueous ions, such as nickel ions (Ni 2+ ), cobalt ions (Co 2+ ), manganese ion (Mn 2+ ), aluminum ions (Al 3+ ), potassium ion (K + ), calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), chloride ion (Cl - ) or fluoride ion (F - ). In some embodiments, the system may include various methods for minimizing the concentration of these contaminants in the Na2SO4 solution 106 generated by the battery manufacturing process.

[0043] For example, a method for minimizing the concentration of contaminants in the generated Na2SO4 solution 106 may include managing the inputs to the battery manufacturing process 100. For example, conventional battery manufacturing systems typically utilize municipal water treated with reverse osmosis, which leaves a large amount of the above-mentioned contaminants in product streams such as the Na2SO4 solution 106. This level of purity is acceptable for conventional manufacturing systems, but is generally unacceptable for electrochemical salt decomposition processes. In contrast, one or more embodiments may include utilizing deionized water in the battery manufacturing process 100 as a method for minimizing the introduction of contaminants. In addition, many reagents and raw materials used in battery manufacturing also introduce various contaminants. In contrast, one or more embodiments also include utilizing reagents and raw materials that are free of contaminants or contain only trace amounts of contaminants in the battery manufacturing process 100.

[0044] The method described herein can further process the generated Na2SO4 solution 106 to generate NaOH and H2SO4. By minimizing the Na2SO4 solution 106, the system can eliminate certain downstream technologies that are usually required to generate NaOH and H2SO4 from the Na2SO4 solution 106.

[0045] As described above, in some embodiments, the system can also process Na2SO4 in solution form (e.g., Na2SO4 solution 106 or Na2SO4 solution 204) generated from the battery manufacturing process 202. For example, Figure 2 A flow chart of a method 200 for converting Na2SO4 into sodium hydroxide (NaOH) 218 ​​and sulfuric acid (H2SO4) 220 via an electrochemical salt decomposition process 212 is shown. The method 200 may include various intermediate treatments of the Na2SO4 solution 204 prior to subjecting the Na2SO4 solution 204 to the electrochemical salt decomposition process 212. For example, in various embodiments, the method 200 may include intermediate treatment steps such as treating the Na2SO4 solution 204 through a crystallizer and / or removing contaminants 208 from the Na2SO4 solution 204 via ion exchange purification.

[0046] For example, in one embodiment, the method 200 may process the Na2SO4 solution 204 through a crystallizer to produce anhydrous Na2SO4 in the form of a crystalline solid or a powder thereof. In addition, in some embodiments, the Na2SO4 solution 204 may include contaminants 208, and the method 200 may further treat the contaminants 208 through an ion exchange process, as discussed in further detail below. In fact, the Na2SO4 solution 204 may include trace amounts of various metals (e.g., nickel (Ni), cobalt (Co), manganese (Mn), aluminum (Al)) with considerable value. The method 200 can process these metals through, for example, crystallization or precipitation reactions, so that the method can separate, recover and / or recycle these trace metals from the Na2SO4 solution 204 and input them back into the battery recycling process 222. In fact, since these processes are located within a combined plant, they can be directly connected to each other to achieve process intensification.

[0047] In one or more embodiments, the byproduct Na2SO4 solution 204 generated by the method 200 from the ammonia recovery process in the battery manufacturing process 202 may include metal contaminants in the form of aqueous ions, such as Ni 2+ 、Co 2+ , Mn 2+ 、Al3 + The pollutants 208 generated by the method 200 may also include chloride and fluoride ions (e.g., Cl - and F -). In some embodiments, the method 200 can generate anhydrous Na2SO4 solid 206 by subjecting the Na2SO4 stream to a crystallizer after ammonia recovery. Typically, the crystallization step is used as a purification step to reduce impurities. In one or more embodiments, a liquid purge stream containing Na2SO4 and contaminants is separated while the Na2SO4 solid main stream is subjected to salt decomposition or sent for sale.

[0048] As described above, in some embodiments, the method 200 can also remove contaminants 208 from the Na2SO4 solution 204 before subjecting the Na2SO4 solution 204 to the electrochemical salt decomposition process 212 to generate NaOH 218 and H2SO4 220. Because electrochemical devices are sensitive to metal impurities, residual metals in the solution stream can poison the membrane and electrodes, thereby increasing the cell resistance and reducing performance. Therefore, many salt decomposition systems require the raw materials to be pure, which requires additional purification steps to remove residual metals, such as those described above. In some embodiments, the method 200 can ensure that the Na2SO4 solution 204 is pure enough to be used in the electrochemical salt decomposition process 212 without one or more purification steps that are conventionally required. For example, in one or more embodiments, the pCAM process serves as a Ca, Mg removal process. In such an embodiment, the method includes an IX purification step and omits the precipitation step.

[0049] For example, in one or more embodiments, the method 200 can utilize a single purification step (e.g., ion exchange purification) to remove contaminants 208 from the Na2SO4 solution 204. In many conventional systems, multiple methods are required to remove various contaminants 208 (e.g., Ca 2+ and Mg 2+ ). For example, conventional systems require multiple processes, including an initial hardness removal step and an ion exchange purification step. In fact, many conventional systems require initial hardness removal to remove ions such as Ca 2+ and Mg 2+ These conventional systems then require an ion exchange purification step to remove the contaminants to concentrations in the parts per billion (ppb) range (e.g., less than 50 ppb for all contaminants and less than 10 ppb for Ca 2+ and Mg 2+Less than 20 ppb). However, the disclosed systems and methods are superior to conventional systems, for example, by eliminating the initial hardness removal step. In these or other embodiments, the method 200 can utilize a single ion exchange purification to remove multivalent ion contaminants to acceptable levels (e.g., less than 20 ppb to 50 ppb) for the electrochemical salt decomposition process 212. The method 200 can remove contaminants 208 via a single purification step, at least in part because the resulting Na2SO4 solution 204 has a low contaminant concentration, as described above with respect to Figure 1 In fact, in one or more embodiments, a single purification step can reduce the contaminant concentration to less than 200 ppb, less than 100 ppb, less than 50 ppb, less than 20 ppb, less than 15 ppb, less than 10 ppb, or less than 5 ppb. In other embodiments, the nature of the battery manufacturing or recycling process can enable the electrochemical salt decomposition process to operate under less stringent contaminant limits and can tolerate up to 5 ppm of impurities.

[0050] In some embodiments, the method of one or more embodiments can purify the Na2SO4 outlet stream (e.g., Na2SO4 204) with an online ion exchange column similar to the ion exchange process described in Spanish Patent Application ES2056752A6 published on October 1, 1994 and U.S. Patent No. 4,707,347 issued on November 17, 1987, both of which are incorporated herein by reference in their entirety. In other embodiments, the method of one or more embodiments can utilize a cation exchange resin to absorb Ni, Co, Mn, Al, and any other residual ionic metal impurities in the solution out of the solution, and then feed the solution into an electrochemical salt decomposition device. As described above, in one or more embodiments, the method of one or more embodiments can recycle the contaminants 208 (e.g., metal contaminants) back into the battery recycling process 222 as recycled metal feedstock.

[0051] In one or more embodiments, the method of one or more embodiments may further process the purified Na2SO4 solution 210 by converting the generated Na2SO4 into NaOH 218 and H2SO4 220 through an electrochemical salt decomposition process 212. In some embodiments, the electrochemical salt decomposition process 212 may include electrolysis 214 or bipolar membrane electrodialysis 216. In one or more embodiments, the electrochemical device may include two compartments or multiple compartments separated by an ion exchange membrane. In addition, the electrochemical salt decomposition process 212 may utilize a membrane electrode design that includes any combination of stainless steel electrodes, nickel-plated steel electrodes, nickel electrodes, and / or mixed metal oxide electrodes. Alternatively, the electrochemical salt decomposition process 212 may utilize an electrode design that changes the electrode half-reactions for oxygen production and / or hydrogen production. For example, one or more embodiments utilize gas diffusion electrodes. Further details on the use of the electrochemical salt decomposition process 212 to decompose Na2SO4 in the purified Na2SO4 solution 210 into NaOH 218 and H2SO4 220 will be referred to. Figures 5 to 10 .

[0052] In addition, the method of one or more embodiments recycles the generated NaOH 218 and / or H2SO4 220 into the battery manufacturing process 202 to form a closed system. For example, whether the electrochemical salt decomposition process 212 is performed using electrolysis 214 or bipolar membrane electrodialysis 216, the method of one or more embodiments can decompose Na2SO4 in the purified Na2SO4 solution 210 to generate NaOH 218 and H2SO4 220, such as Figure 2As shown. In addition, the method of one or more embodiments can recycle the generated NaOH 218 and H2SO4 220 into the battery manufacturing process 202. Therefore, the method of one or more embodiments can be operated as a closed system, wherein the Na2SO4 generated from the battery manufacturing process 202 is incorporated into the process for converting Na2SO4 into NaOH 218 and H2SO4 220, and the NaOH 218 and H2SO4 220 generated by decomposing Na2SO4 are incorporated into the battery manufacturing process 202. By forming a single closed system for circulation, the method of one or more embodiments can achieve high efficiency, thereby saving capital and cost. For example, by forming a closed system, the method can avoid the need for a large amount of equipment originally used to concentrate H2SO4 to a high concentration. In addition to eliminating the impurity removal or concentration step in the electrochemical salt decomposition process by controlling impurities, other methods and embodiments can achieve efficiency by adjusting the battery manufacturing process to achieve process intensification of the electrochemical process. One such embodiment is to modify the battery manufacturing process to handle impure acids or bases, so that a more efficient but impure acid or base dual-compartment electrochemical cell can be selected. For example, modifications to the cell manufacturing process may include changing the recipe and operating conditions (concentration, pH, temperature, residence time) of the pCAM reactor process, or changing the conditions of the pCAM filtration process (amount of rinse solution, composition of rinse solution, etc.).

[0053] Reference now Figure 3 , which shows a process flow diagram of a method 300 for generating lithium sulfate (Li2SO4) from a battery recycling process according to one or more embodiments. For example, in one embodiment, the method 300 can extract Li2SO4 and other valuable metals (e.g., Ni, Co, Mn, Al) from the processed recycled battery material 302 in a reduction leaching process using H2SO4 and hydrogen peroxide (H2O2). Some reactions are described by simplified chemical reaction equations (2), (3), and (4) shown below.

[0054] MO (s) + H2SO4 (aq) → MSO4 (aq) + H2O (l) (2)

[0055] Li2O (s) + H2SO4 (aq) → Li2SO4 (aq) + H2O (l) (3)

[0056] Al2O3 (s) + 3H2SO4 (aq) → Al2(SO4)3(aq) + 3H2O (l) (4)

[0057] With respect to equation (2), the metal oxide (MO) solid contains a metal (M), such as Ni, Co, and Mn, to name a few. Similarly, the resulting aqueous form of the metal sulfate (MSO4) contains the corresponding metal, such as NiSO4, CoSO4, and MnSO4, among others.

[0058] After the leaching process, the method 300 can separate the mixture of MSO4, Li2SO4, and Al2(SO4)3 dissolved in the leachate 304 into their components, such as Al precipitate 310, metal precipitate 312, and Li2SO4 (e.g., from Li2SO4 solution 308) using separation techniques involving crystallization, precipitation, solid-liquid separation, and particle size separation. The metal precipitate 312 can include, but is not limited to, MSO4, Al(OH)3, and M(OH)2 solids, where the metal (M) includes Ni, Co, and Mn, to name a few examples. The method 300 can also crystallize solid Li2SO4 as lithium sulfate monohydrate (Li2SO4·H2O) 314 from the Li2SO4 solution 308 produced by the separation technique. In one embodiment, the method 300 can produce a relatively pure final Li2SO4·H2O 314, which can have a composition as described in Table 2 below.

[0059] Table 2. Approximate composition of lithium sulfate monohydrate (LSM)

[0060] element unit value Li wt% 10.43 Na ppm 100 Ca wt% 0.5 Mg ppm 1-200 Al ppm 0 Fe ppm 0 Ni ppm 100 Co ppm 0 Cu ppm 0 <![CDATA[SO4]]> wt% 75-76％ <![CDATA[H2O]]> wt% 14.4-14.5％

[0061] As shown in Table 2, the lithium weight percent can be about 10.43, with a theoretical limit of about 10.85, which means that the total purity of the Li2SO4 outlet stream recovered from the lithium battery is about 96%. Residual sodium is a contaminant resulting from the use of municipal water, which the method 300 can remove or minimize by treating the water with reverse osmosis or by deionization. The presence of calcium (Ca) and magnesium (Mg) is due to the reagents used by the method 300 during the recovery process. The method 300 can remove Al, iron (Fe), Co, and copper (Cu) before chemical treatment, but it is possible that some Ni will be carried into the composition of the Li2SO4·H2O 314.

[0062] The weight percentage of the remaining chemical elements such as sulfate (SO4) can be about 75% to about 76%, with a theoretical limit of about 75%, a slight excess from impurities, and most of it in the form of sulfate. The weight percentage of water (H2O) can be about 14.1% to about 14.5%, most of which is combined in monohydrates, and very little free water remains.

[0063] In some embodiments, the method 300 can produce a Li2SO4 product having a low contaminant concentration, such as Li2SO4·H2O 314 or a Li2SO4 solution. In fact, the method 300 can produce a Li2SO4 solution in which the concentration of at least some contaminants in the solution is less than 20 parts per million (ppm). The resulting Li2SO4 solution may contain various contaminants in the form of aqueous ions, such as nickel ions (Ni 2+ ), cobalt ions (Co 2+ ), copper ions (Cu 2+ ), aluminum ions (Al3+), iron ions (Fe 2+ ), calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), chloride ion (Cl - ) and / or fluoride ions (F - ). In some embodiments, method 300 may include various methods to minimize the concentration of these contaminants in the Li2SO4 solution generated from the battery recycling process.

[0064] For example, methods for minimizing the concentration of contaminants in the generated Li2SO4 solution may include managing the inputs to the battery recycling process. For example, conventional battery manufacturing systems typically utilize water from municipal sources with little or no filtration of the water, which can introduce various of the above-mentioned contaminants into product streams such as Li2SO4 solutions. For example, as described above, using tap water may introduce sodium into the system. However, method 300 can minimize the sodium in the Li2SO4 solution by utilizing reverse osmosis water and / or deionized water, such as water used in a leaching process containing H2SO4 and H2O2. Method 300 can further minimize other contaminants by ensuring that reagents (e.g., precipitating reagents 306) and raw materials are free of contaminants or have only trace amounts of contaminants. For example, method 300 can utilize a Ca-free 2+ or Mg 2+ In addition, method 300 can be performed by utilizing the method without introducing F - reagents and utilizing battery raw materials (e.g., battery waste) without electrolytes (such as processed recycled battery materials 302) to minimize F - Additionally, in some embodiments, the method 300 can utilize the generated LiOH to control the pH, rather than using NaOH as the pH control.

[0065] In certain embodiments, by minimizing the concentration of contaminants in the Li2SO4 solution, the method 300 can minimize downstream purification technologies. For example, the method 300 can further process the resulting Li2SO4 solution to generate LiOH and H2SO4. By minimizing the concentration of contaminants in the Li2SO4 solution, the method 300 can eliminate certain downstream technologies that are typically required to generate LiOH and H2SO4 from the Li2SO4 solution, as discussed in further detail below.

[0066] As described above, in some embodiments, the method 300 can further process the Li2SO4 in solution (e.g., Li2SO4 solution 404) generated from the battery recycling process 402. For example, Figure 4 A process flow diagram of a method 400 for converting Li2SO4 into LiOH 418 and H2SO4 420 via an electrochemical salt decomposition process 412 according to one or more embodiments is shown. The method 400 may include various intermediate treatments of the Li2SO4 solution 404 prior to subjecting the Li2SO4 solution 404 to the electrochemical salt decomposition process 412, such as Figure 4 For example, in various embodiments, the method 400 may include intermediate processing steps, such as treating the Li2SO4 solution 404 through a crystallizer and / or removing contaminants 408 from the Li2SO4 solution 404 through ion exchange purification.

[0067] For example, in one or more embodiments, the method 400 can further process the Li2SO4 solution 404 through a crystallizer to produce anhydrous lithium sulfate solid. In addition, in some embodiments, the Li2SO4 solution 404 may include contaminants 408, and the method 400 can further process the contaminants 408 through an ion exchange process, as discussed in further detail below. In practice, the Li2SO4 solution 404 may include contaminants 408, such as metal contaminants in the form of water ions, such as Ni 2+ 、Co 2+ 、Al 3+ and / or other contaminants such as chloride and fluoride ions (e.g. Cl - and F - ). In some embodiments, the method 400 may subject the Li2SO4 solution 404 to a crystallizer process to produce anhydrous lithium sulfate (Li2SO4) solid 406. The method 400 may also produce metals (including chlorine and fluorine contaminants) in their solid ionic form in the Li2SO4 solid 406 as part of the Li2SO4 solid crystal structure. In some embodiments, the method 400 may extract the solid ionic form and recycle it back into the battery recycling process 402. In fact, because these processes are located in an integrated plant, they can be directly connected to each other to achieve process intensification.

[0068] Although the Li2SO4.H2O may have the composition shown above, those skilled in the art will appreciate that the Li2SO4.H2O may have other compositions or concentrations depending on the processing steps.

[0069] In addition, in some embodiments, method 400 can utilize a single stage crystallization to crystallize LiOH. Indeed, in these or other embodiments, method 400 can eliminate the need for multiple stages of crystallization by minimizing the sodium content in the feedstock (e.g., Li2SO4 solution 404). For example, method 400 can limit the sodium content by utilizing LiOH 418 produced from the electrochemical salt decomposition process 412 as a pH control rather than using NaOH, as described in further detail below. In addition, in some cases, method 400 can use LiOH instead of lime to form a metal precipitate. In other cases, LiOH can be combined with CO2 to form a Li2CO3 solution, which can be used as part of the impurity removal step in place of Na2CO3. In addition, as described above with respect to methods for generating Li2SO4 from battery recycling processes (see Figure 3 ), method 400 can minimize sodium by utilizing reverse osmosis water and / or deionized water in an intermediate purification process prior to electrochemical salt decomposition process 412. In addition, method 400 can utilize reagents that do not introduce sodium, specifically by replacing Na2CO3 with CO2 in a process including a multivalent cation removal step prior to salt decomposition, using lime instead of caustic soda in a precipitation step of an optional pre-salt decomposition purification step, and using an electrochemical process instead of a chemical process where possible. In addition, method 400 can utilize battery raw materials that do not contain sodium (e.g., battery waste in battery recycling process 402). In addition, in one or more embodiments, method 400 can include venting to manage impurity accumulation, as discussed in further detail below.

[0070] As described above, in some embodiments, the method 400 may further remove contaminants 408 from the Li2SO4 solution 404 before subjecting the Li2SO4 solution 404 to the electrochemical salt decomposition process 412 to produce LiOH 418 and H2SO4 420. As described above, because electrochemical devices are sensitive to metal impurities, residual metals in the solution stream can poison the membrane and electrodes, thereby increasing cell resistance and reducing performance. Therefore, many salt decomposition systems require the feedstock to be pure, which requires additional purification steps to remove residual metals. Therefore, in some embodiments, the method of one or more embodiments can ensure that the Li2SO4 solution 404 is pure enough for use in the electrochemical salt decomposition process 412 without the need for a large number of purification steps. For example, the method of one or more embodiments can purify the Li2SO4 solution 404 with an online ion exchange column or cation exchange resin, such as with respect to the purification and Figure 2 described.

[0071] In addition, the methods of one or more embodiments may utilize a single purification step (e.g., ion exchange purification) similar to the above description of Na2SO4 solution and Figure 2 The ion exchange purification method described above removes contaminants 408 from the Li2SO4 solution 404. In fact, the method of one or more embodiments can use a similar method at least in part for the Li2SO4 solution 404, because as described above with respect to Figure 3 The concentration of contaminants 408 in the Li2SO4 produced from the battery recycling process is extremely low.

[0072] As described above, in some embodiments, the method of one or more embodiments can convert the Li2SO4 generated from the battery recycling process 402 into LiOH418 and H2SO4 420 in the purified Li2SO4 solution 410 through the electrochemical salt decomposition process 412. In addition, the method of one or more embodiments can utilize the same method as described above with respect to Figure 2 The same method and apparatus described for converting Na2SO4 into NaOH and H2SO4, converts the Li2SO4 in the purified Li2SO4 solution 410 into LiOH 418 and H2SO4 420. In fact, the reference Figures 5 to 10 Some methods and equipment are discussed in further detail.

[0073] Additionally, in one or more embodiments, method 400 may include generating Li2SO4 from a battery recycling process and converting the generated Li2SO4 into LiOH 418 and H2SO4 420 in a closed system, at least by recycling H2SO4 420 into the battery recycling process. Figure 4As shown, whether the electrochemical salt decomposition process 412 is performed using electrolysis 414 or bipolar membrane electrodialysis 416, the method 400 can decompose the Li2SO4 in the purified Li2SO4 solution 410 to generate LiOH418 (e.g., in a LiOH solution) and H2SO4 420 (e.g., in a solution). In fact, by incorporating the Li2SO4 generated from the battery recycling process 402 into the process of converting the Li2SO4 into LiOH 418 and H2SO4 420, and recycling the H2SO4 420 back to the process of generating Li2SO4, the method 400 can be operated as a closed system. For example, the H2SO4 420 can be recycled back to the process of leaching the treated recycled battery material 302. In addition, the method 400 can recycle the generated LiOH 418 (e.g., as a LiOH solution) back to the battery recycling process 402 or the battery manufacturing process 422. In practice, the LiOH solution containing LiOH 418 can be sent to a crystallizer to generate a LiOH·H2O solid, which can be sold or sent to a battery manufacturing process 422. In addition to eliminating impurity removal or concentration steps in the electrochemical salt decomposition process by managing impurities, other methods and embodiments can achieve efficiency by adjusting the battery recycling process to achieve process intensification of the electrochemical process. One such embodiment would be to modify the battery recycling process to handle impure acids or bases, enabling the selection of a more efficient dual-compartment electrochemical cell that produces impure acids or bases. In addition, modifications to the battery recycling process can include one or more of the following: (1) changing the location of acid recovery back into the battery recycling process, (2) reducing the addition of water and purchased acid (or base) to accommodate impure acids (or bases), or (3) controlling the conditions of salt decomposition and battery recycling to avoid causing any link in the system to become supersaturated with Li2SO4, resulting in Li2SO4 crystallization, thereby causing product loss and operational failure.

[0074] In addition, in some embodiments, the method 400 of generating Li2SO4 from a battery recycling process and converting the generated Li2SO4 into LiOH 418 and H2SO4 420 in a closed system may include removing impurity accumulation through bleed. For example, in a closed or closed-loop system, trace concentrations of impurities can accumulate over time, leading to inefficiency and degradation of system devices and equipment and reduced product quality. In one or more embodiments, the method 400 may also include recovering valuable materials within the bleed stream, such as generating lithium carbonate (Li2CO3) from the bleed stream to maximize Li + In these or other embodiments, method 400 can utilize CO2 and LiOH in the exhaust stream to avoid introducing Na2CO3 by adding Na2CO3. +Additionally, the blowdown stream can be processed in a zero liquid discharge evaporator to recover water.

[0075] Reference now Figure 5 , which shows the electrolytic salt decomposition process using a two-compartment electrolysis cell 502 and a three-compartment electrolysis cell 504 to remove Na2SO4 from, for example, Figure 1 The Na2SO4 outlet stream produced in Figure 2 Method 500 for converting a purified Na2SO4 solution into NaOH and H2SO4. Similarly, Figure 6 The electrolytic salt decomposition process using a dual compartment electrolysis cell 602 and a triple compartment electrolysis cell 604 is shown to convert Li2SO4 from, for example, Figure 2 The Li2SO4 outlet stream produced in Figure 4 A method 600 for converting a purified Li2SO4 solution into LiOH and H2SO4.

[0076] In general, Figure 5 and Figure 6 The two transformations shown in are basically similar, except that the initial chemical solutions are Na2SO4 and Li2SO4, respectively, and the resulting products are NaOH and LiOH, respectively. Both transformations can produce H2SO4.

[0077] like Figure 5 and Figure 6 As shown, for three-compartment electrolysis cell 504, the method of one or more embodiments may include an anion exchange membrane and a cation exchange membrane. Depending on the nature, these membranes may be semipermeable to allow specific ions (e.g., anions or cations) to be transported across the membrane. For two-compartment electrolysis cell 502, the method of one or more embodiments may utilize a cation exchange membrane or an anion exchange membrane.

[0078] In the three-compartment electrolysis cell 504, the method of one or more embodiments may include providing a Na2SO4 solution 506 to the center compartment between the anion exchange membrane and the cation exchange membrane ( Figure 5 Under the applied voltage, the sodium ions (Na + ) can migrate to the cathode compartment through the cation exchange membrane (CEM), while sulfate ions (SO4 2- ) can migrate to the anode compartment through an anion exchange membrane (AEM). Through the anode and cathode reactions, the method of one or more embodiments can generate H by water oxidation and reduction, respectively. + and OH - The reaction is as described in formula (5) and (6).

[0079] Anode: 2H2O → O2 + 4H + +4e - (5)

[0080] Cathode: 4H2O + 4e - → 2H2 + 4OH - (6)

[0081] In the anode chamber, H + With SO4 2- Combine to form H2SO4, while in the cathode chamber, OH - with Na + In some embodiments, the method of one or more embodiments may utilize other electrochemical reactions besides oxidation and reduction of water to produce H at the anode. + and OH is produced at the cathode - For example, one or more embodiments include variations that utilize oxygen to depolarize the cathode and hydrogen to depolarize the anode.

[0082] In a dual compartment electrolysis cell 502 with a CEM, the method of one or more embodiments may include providing a Na2SO4 solution 506 to the anode compartment. Similarly, under an applied voltage, Na + can migrate through the CEM to the cathode compartment, where Na + With the generated OH - Combined to produce NaOH. In the anode chamber, SO4 2- With the generated H + Combination produces H2SO4.

[0083] In a dual compartment electrolysis cell 502 with an AEM, the method of one or more embodiments may include providing a Na2SO4 solution 506 to the cathode compartment. Similarly, under an applied voltage, SO4 2- can migrate through the AEM to the anode chamber, where SO4 2- With the generated H + Combine to produce H2SO4. In the cathode chamber, Na + With the generated OH - The combination produces NaOH.

[0084] As described above, in some embodiments, the method may use the dual or triple compartment electrolysis cells 502 to 504 as described above to convert the Na2SO4 solution 506 generated from the outlet stream of the battery manufacturing process into NaOH and H2SO4 through an electrochemical salt decomposition process. In addition, as described above, the method of one or more embodiments may return the resulting NaOH to the process for producing the precursor cathode active material (pCAM) (see equation (1)) and return the H2SO4 to the battery recycling process (see equations (2), (3) and (4)), so that the electrochemical salt decomposition allows for a closed-loop battery recycling and manufacturing process. In other words, the system generates Na2SO4 in a closed-loop battery recycling and manufacturing system and converts it into NaOH and H2SO4, so that the Na2SO4 outlet stream generated from the battery manufacturing process is fed into the process for converting Na2SO4 into NaOH and H2SO4, and the NaOH and H2SO4 generated in the conversion process are fed into the battery manufacturing process.

[0085] for Figure 6 In the process of decomposing the Li2SO4 salt in the present invention, the method of one or more embodiments can be carried out by replacing Na2SO4 with Li2SO4, using the same method as described above for Figure 5 The described Na2SO4 salt decomposition process is similar to that of the two-compartment and three-compartment electrolysis cells and will not be described in detail herein. However, in this case, the system produces LiOH instead of NaOH on the cathode side, while still producing H2SO4 on the anode side.

[0086] In some embodiments, the method of one or more embodiments may use a dual compartment electrolysis cell 602, a three compartment electrolysis cell 604, or an electrochemical cell having more than three compartments as described above to convert a Li2SO4 solution 606 generated from an outlet stream of a battery recycling process into LiOH and H2SO4 through an electrochemical salt decomposition process. In further embodiments, the method of one or more embodiments may further process and calcine the resulting LiOH and M(OH)2 to produce a lithium-rich cathode active material (CAM), while reusing H2SO4 in the battery recycling process (see equations (2), (3), and (4)), such that the electrochemical salt decomposition allows for a battery recycling and manufacturing closed loop process. In other words, the method of one or more embodiments generates Li2SO4 in a closed loop battery recycling and manufacturing system and converts it into LiOH and H2SO4, such that the Li2SO4 outlet stream generated from the battery recycling process is fed into a process for converting Li2SO4 into LiOH and H2SO4, and the LiOH and H2SO4 generated by the conversion process are fed into a battery recycling process and / or a battery manufacturing process.

[0087] Furthermore, in some embodiments, the methods of one or more embodiments may utilize bipolar membrane electrodialysis as the salt decomposition process as described above. For example, Figure 7 A method 700a for converting Li2SO4 into LiOH and H2SO4 by a salt decomposition process using bipolar membrane electrodialysis is shown according to one or more embodiments. Figure 7 The salt decomposition process using bipolar membrane electrodialysis is shown to convert Li2SO4 from e.g. Figure 4 The Li2SO4 outlet stream produced in Figure 4 The purified Li2SO4 solution is converted into LiOH and H2SO4.

[0088] like Figure 7 As shown, in one or more embodiments, the methods of one or more embodiments may utilize an electrodialysis cell comprising an anode and a cathode separated by a plurality of membranes defining a plurality of compartments. For example, Figure 7 A bipolar membrane electrodialysis system is shown, which includes an anode, followed by a series of membranes, such as a CEM, an AEM, a bipolar exchange membrane (BPM), a second CEM, a second AEM, a second BPM, and a third CEM, followed by a cathode. Figure 7 As shown, the bipolar membrane electrodialysis system includes compartments between each membrane, between the anode and the first CEM, and between the cathode and the third CEM. Depending on the nature, the CEM and AEM may be semipermeable to allow specific ions (e.g., anions or cations) to be transported across the membrane. Figure 7 and Figure 8 The bipolar membrane electrodialysis system shown comprises two cells, and each cell has three compartments. In alternative embodiments, the bipolar membrane electrodialysis system comprises two compartments, three compartments or more compartments per cell. In further embodiments, the bipolar membrane electrodialysis system can comprise any non-zero number of cells.

[0089] In some embodiments, a method of utilizing the above-described electrodialysis cell may include injecting an electrolyte, a Li2SO4 solution 702, a dilute acid, and a dilute base into compartments of the cell to produce a strong base (e.g., LiOH) and a strong acid (e.g., H2SO4). For example, the method may include injecting an electrolyte into a compartment between an end electrode and a CEM. In addition, the method may include injecting a Li2SO4 solution 702 into a compartment between a CEM and an AEM, injecting a dilute acid into a compartment between an AEM and a BPM, and injecting a dilute base into a compartment between a BPM and a CEM. Under an applied voltage and / or current, the Li2SO4 solution 702 is injected into the compartment between the AEM and the BPM. + can migrate from the Li2SO4 solution compartment to the adjacent base compartment through the CEM, while SO4 2-can migrate from the Li2SO4 solution compartment through the AEM to the adjacent acid compartment. Through the BPM reaction driven by applied voltage and / or current, the system can generate H from water through ion transfer. + and OH - Each BPM may include a cation exchange layer (CEL) and an anion exchange layer (AEL). The reaction is as described in equation (7).

[0090] H2O → H + + OH - (7)

[0091] AEL prevents Li + Migrate through each BPM while allowing OH - Entering the alkali compartment. CEL prevents SO4 2- Migrate through each BPM while allowing the generated H + In the base compartment, OH - With Li + Combined to produce LiOH, in the acid compartment, H + With SO4 2- Combined to produce H2SO4. In addition, although not shown in the figure, it can be understood from the disclosure herein that all CEMs can have Li + , and all AEMs can have SO4 passing through them 2- In some embodiments, the method may include using other arrangements of membranes within an electrodialysis cell to achieve electrochemical salt decomposition, as would be readily appreciated by one of ordinary skill in the art.

[0092] also, Figure 8 A method 802 for converting Na2SO4 into NaOH and H2SO4 by a salt decomposition process using bipolar membrane electrodialysis is shown according to one or more embodiments. Figure 8 The salt decomposition process using bipolar membrane electrodialysis is shown to remove Na2SO4 from e.g. Figure 2 The Na2SO4 outlet stream produced in Figure 2 The purified Na2SO4 solution is converted into NaOH and H2SO4.

[0093] like Figure 8 As shown, in one or more embodiments, the methods of one or more embodiments may utilize an electrodialysis cell comprising an anode and a cathode separated by a plurality of membranes defining a plurality of compartments. For example, Figure 8 A bipolar membrane electrodialysis system is shown, which includes an anode, followed by a series of membranes, such as a CEM, an AEM, a bipolar exchange membrane (BPM), a second CEM, a second AEM, a second BPM, and a third CEM, followed by a cathode. Figure 8 As shown, the bipolar membrane electrodialysis system includes compartments between each membrane, between the anode and the first CEM and between the cathode and the third CEM. Depending on the nature, the CEMs and AEMs may be semipermeable to allow transport of specific ions (eg, anions or cations) across the membrane.

[0094] In some embodiments, a method of utilizing the above electrolytic cell may include injecting an electrolyte, a Na2SO4 solution 702b, a dilute acid, and a dilute alkali into compartments of the cell to produce a strong base (e.g., NaOH) and a strong acid (e.g., H2SO4). For example, the method may include injecting an electrolyte into a compartment between the anode and the first CEM and a compartment between the cathode and the third CEM. In addition, the method may include injecting a Na2SO4 solution 702b into a compartment between the CEM and the AEM, injecting a dilute acid into a compartment between the AEM and the BPM, and injecting a dilute alkali into a compartment between the BPM and the CEM. Under an applied voltage, Na + can migrate through the second CEM to the compartment between the first BPM and the second CEM, SO4 2- can migrate to the compartment between the second AEM and the second BPM through the second AEM. Through the BPM reaction, the system can produce H through the oxidation and reduction of water + and OH - Each BPM may include a cation exchange layer (CEL) and an anion exchange layer (AEL).

[0095] The AEL of the first BPM prevents Na + Migrate through the first BPM, the CEL of the second BPM blocks SO4 2- Migrate through the second BPM. In the compartment between the first BPM and the second CEM, OH - with Na + Combined to produce NaOH, in the compartment between the second AEM and the second BPM, H + With SO4 2- In some embodiments, the method can utilize other electrochemical reactions other than the oxidation and reduction of water to generate H at the BPM. + and OH - Furthermore, although not shown in the figure, it is understood that all CEMs may have Na + , and all AEMs can have SO4 passing through them 2- .

[0096] In some embodiments, the method may include using other arrangements of membranes within an electrodialysis cell to achieve electrochemical salt decomposition, as would be readily appreciated by one of ordinary skill in the art. For example, Fig. 9 and10 The conversion of Li2SO4 to LiOH and H2SO4 through a salt decomposition process using a bipolar membrane electrodialysis cell with a dual compartment is shown according to one or more embodiments. The dual compartment bipolar electrodialysis functions similarly to the three compartment except that the central salt compartment is combined with either the acid compartment or the base compartment.

[0097] For example, in a dual compartment bipolar electrodialysis cell system 900 with a CEM, the method of one or more embodiments may include injecting a Li2SO4 solution 902 into the acid compartment. Under an applied voltage, Li + can migrate to the alkaline compartment through CEM, where Li + With the generated OH - Combine to produce LiOH. In the acid compartment, SO4 2- With the generated H + The combination produces H2SO4. A mixture of Li2SO4 solution and H2SO4 flows out of the acid compartment. Pure LiOH solution flows out of the base compartment.

[0098] In a dual compartment electrodialysis cell 1000 with an AEM, the method of one or more embodiments may include injecting a Na2SO4 solution 1002 into the base compartment. Similarly, under an applied voltage, SO4 2- It can migrate to the acid compartment through AEM, where SO4 2- With the generated H + Combine to produce H2SO4. In the base compartment, Li + With the generated OH - The combination produces LiOH. A mixture of Li2SO4 solution and LiOH flows out of the base compartment. Pure H2SO4 solution flows out of the acid compartment.

[0099] Although Fig. 9 and Fig.10 Dual-chamber bipolar electrodialysis cell systems 900 and 1000 are shown for converting Li2SO4 to LiOH and H2SO4, but it is apparent to one of ordinary skill in the art that similar systems can be used to convert Na2SO4 to NaOH and H2SO4. For example, the method of one or more embodiments may include injecting Na2SO4 solution into system 900 and system 1000 instead of Li2SO4 solution to convert Na2SO4 to H2SO4 via the above-described method. Fig. 9 and Fig.10 Similar mechanisms are described for the generation of NaOH and H2SO4.

[0100] Figures 1 to 10, corresponding text and embodiments provide a variety of different systems and methods for generating Na2SO4 and Li2SO4 from a battery manufacturing process and a battery recycling process, respectively, and converting Na2SO4 and Li2SO4 into NaOH and LiOH in combination with H2SO4, respectively. In addition to the foregoing, embodiments may also be described in terms of flow charts including operations for achieving specific results. For example, Fig.11 and Fig.12 A flowchart illustrating an example operational sequence according to one or more embodiments is shown.

[0101] Although Fig.11 and 12 Steps according to some embodiments are shown, but alternative embodiments may omit, add, reorder, and / or adjust Fig.11 and 12 Any of the actions shown in . Fig.11 and Fig.12 The operation can be performed as part of a method. Alternatively, the system can perform Fig.11 and Fig.12 In addition, the operations described herein may be performed repeatedly or in parallel with each other, or in parallel with different instances of other identical or similar operations.

[0102] Fig.11 A series of exemplary operations 1100 for generating Na2SO4 from a battery manufacturing process and converting Na2SO4 into NaOH and H2SO4 are shown. The series of operations 1100 may include an operation 1102 of generating sodium sulfate (Na2SO4) from a battery manufacturing process; and an operation 1104 of converting the generated sodium sulfate (Na2SO4) into sodium hydroxide (NaOH) and sulfuric acid (H2SO4).

[0103] For example, in one or more embodiments, a series of operations 1100 may include generating sodium sulfate (Na2SO4) from a battery manufacturing process; and converting the generated sodium sulfate (Na2SO4) into sodium hydroxide (NaOH) and sulfuric acid (H2SO4) through an electrochemical salt decomposition process.

[0104] In one or more embodiments, the electrochemical salt decomposition process comprises one of electrolysis or bipolar membrane electrodialysis.

[0105] Furthermore, in some embodiments, the electrochemical salt splitting process utilizes a membrane electrode design that includes at least one of a stainless steel electrode, a nickel-plated steel electrode, a nickel electrode, or a mixed metal oxide electrode.

[0106] Furthermore, in some embodiments, the electrochemical salt decomposition process utilizes a membrane electrode design that changes the electrode half-reactions for oxygen production and / or hydrogen production. More specifically, in one or more embodiments, the electrode design includes a gas diffusion electrode.

[0107] Additionally, in some embodiments, wherein generating sodium sulfate (Na2SO4) from a battery manufacturing process includes generating a sodium sulfate solution, wherein the concentration of contaminants in the sodium sulfate solution is less than 20 ppm (20 parts per million).

[0108] In some embodiments, the contaminants include nickel ions (Ni 2+ ), cobalt ions (Co 2+ ), manganese ion (Mn 2+ ), aluminum ions (Al 3+ ), potassium ion (K + ), calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), chloride ion (Cl - ) or fluoride ion (F - )

[0109] Additionally, in some embodiments, converting the generated sodium sulfate (Na2SO4) into sodium hydroxide (NaOH) and sulfuric acid (H2SO4) includes removing contaminants from the sodium sulfate solution using a single ion exchange purification.

[0110] Furthermore, in some embodiments, the series of operations 1100 may include recycling at least one of sodium hydroxide (NaOH) or sulfuric acid (H2SO4) into the battery manufacturing process to form a closed system.

[0111] Fig.12 An example of a series of operations 1200 for generating Li2SO4 from a battery recycling process and converting Li2SO4 into LiOH and H2SO4 is shown. The series of operations 1200 may include an operation 1202 of generating lithium sulfate (Li2SO4) from a battery recycling process; and an operation 1204 of converting the generated lithium sulfate (Li2SO4) into lithium hydroxide (LiOH) and sulfuric acid (H2SO4).

[0112] Furthermore, in some embodiments, the series of operations 1200 may include generating lithium sulfate (Li2SO4) from a battery recycling process; and converting the generated lithium sulfate (Li2SO4) into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) through an electrochemical salt decomposition process.

[0113] In one or more embodiments, the electrochemical salt decomposition process comprises one of electrolysis or bipolar membrane electrodialysis.

[0114] Furthermore, in some embodiments, the electrochemical salt decomposition process utilizes an electrochemical electrode design that includes at least one of a stainless steel electrode, a nickel-plated steel electrode, a nickel electrode, or a mixed metal oxide electrode.

[0115] Furthermore, in some embodiments, the electrochemical salt decomposition process utilizes an electrode design that alters the electrode half-reactions for oxygen production and / or hydrogen production. More specifically, in one or more embodiments, the electrode design includes a gas diffusion electrode.

[0116] Additionally, in some embodiments, generating lithium sulfate (Li2SO4) from a battery recycling process includes leaching the recovered battery material with a leaching solution comprising sulfuric acid (H2SO4), hydrogen peroxide (H2O2), and at least one of deionized water or reverse osmosis water.

[0117] In some embodiments, generating lithium sulfate (Li2SO4) from a battery recycling process includes generating a lithium sulfate solution, wherein a concentration of contaminants in the lithium sulfate solution is less than 20 ppm (20 parts per million).

[0118] Additionally, in some embodiments, the contaminants include nickel ions (Ni 2+ ), cobalt ions (Co 2+ ), copper ions (Cu 2+ ), aluminum ions (Al 3+ ), iron ions (Fe 2+ ), calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), chloride ion (Cl - ) or fluoride ion (F - )

[0119] Furthermore, in some embodiments, generating the lithium sulfate solution includes limiting the battery feedstock in the battery recycling process to at least one of battery waste that does not contain an electrolyte or battery cells that use an electrolyte that does not contain fluorine.

[0120] Additionally, in some embodiments, converting the generated lithium sulfate (Li2SO4) into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) includes removing contaminants from the lithium sulfate solution using a single ion exchange purification.

[0121] In one or more embodiments, converting the generated lithium sulfate (Li2SO4) into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) includes crystallizing the lithium hydroxide (LiOH) using a single stage crystallization.

[0122] Furthermore, in some embodiments, lithium sulfate (Li2SO4) is generated from the battery recycling process, and the generated lithium sulfate (Li2SO4) is converted into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) in a closed system by recycling the sulfuric acid (H2SO4) into the battery recycling process.

[0123] Furthermore, in some embodiments, the series of operations 1200 can include recycling the generated lithium hydroxide (LiOH) back to at least one of a battery recycling process or a battery manufacturing process.

[0124] Although exemplary embodiments have been specifically shown and described, it will be appreciated by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the embodiments covered by the appended claims. For example, other useful embodiments may be realized if the operations of the disclosed techniques are performed in a different order and / or if the components in the disclosed systems are combined in a different manner and / or replaced or supplemented by other components. Therefore, other embodiments are within the scope of the present disclosure.

Claims

1. A method comprising: Sodium sulfate (Na2SO4) is generated from the battery manufacturing process; and The generated sodium sulfate (Na2SO4) is converted into sodium hydroxide (NaOH) and sulfuric acid (H2SO4) through an electrochemical salt decomposition process.

2. The method of claim 1, wherein the electrochemical salt decomposition process comprises one of electrolysis or bipolar membrane electrodialysis.

3. The method of claim 2, wherein the electrochemical salt decomposition process utilizes a membrane electrode design comprising at least one of a stainless steel electrode, a nickel-plated steel electrode, a nickel electrode, or a mixed metal oxide electrode.

4. The method of claim 2, wherein the electrochemical salt decomposition process utilizes an electrode design that changes the electrode half-reaction for oxygen or hydrogen production.

5. The method of claim 1, wherein generating sodium sulfate (Na2SO4) from the battery manufacturing process comprises generating a sodium sulfate solution, wherein the concentration of contaminants in the sodium sulfate solution is less than 20 parts per million (ppm).

6. The method according to claim 5, wherein the contaminants include nickel ions (Ni 2+ ), cobalt ions (Co 2+ ), manganese ion (Mn 2+ ), aluminum ions (Al 3+ ), potassium ion (K + ), calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), chloride ion (Cl - ) or fluoride ion (F - ) 7. The method of claim 5, wherein converting the generated sodium sulfate (Na2SO4) into sodium hydroxide (NaOH) and sulfuric acid (H2SO4) comprises removing contaminants from the sodium sulfate solution using single ion exchange purification.

8. The method of claim 1, further comprising recycling at least one of sodium hydroxide (NaOH) or sulfuric acid (H2SO4) into the battery manufacturing process to form a closed system.

9. A method comprising: Lithium sulfate (Li2SO4) is produced from the battery recycling process; and The generated lithium sulfate (Li2SO4) is converted into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) through an electrochemical salt decomposition process.

10. The method of claim 9, wherein the electrochemical salt decomposition process comprises one of electrolysis or bipolar membrane electrodialysis.

11. The method of claim 10, wherein the electrochemical salt decomposition process utilizes an electrochemical electrode design comprising at least one of a stainless steel electrode, a nickel-plated steel electrode, a nickel electrode, or a mixed metal oxide electrode.

12. The method of claim 10, wherein the electrochemical salt decomposition process utilizes an electrode design that modifies the electrode half-reactions for oxygen or hydrogen production.

13. The method of claim 9, wherein generating lithium sulfate (Li2SO4) from the battery recycling process comprises leaching the recovered battery material with a leaching solution comprising sulfuric acid (H2SO4), hydrogen peroxide (H2O2), and at least one of deionized water or reverse osmosis water.

14. The method of claim 9, wherein generating lithium sulfate (Li2SO4) from the battery recycling process comprises generating a lithium sulfate solution, wherein the concentration of contaminants in the lithium sulfate solution is less than 20 parts per million (ppm).

15. The method of claim 14, wherein the contaminants include nickel ions (Ni 2+ ), cobalt ions (Co 2+ ), copper ions (Cu 2+ ), aluminum ions (Al 3+ ), iron ions (Fe 2+ ), calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), chloride ion (Cl - ) or fluoride ion (F - ) 16. The method of claim 14, wherein generating the lithium sulfate solution comprises limiting the battery feedstock in the battery recycling process to at least one of battery waste that does not contain an electrolyte or battery cells that use an electrolyte that does not contain fluorine.

17. The method of claim 14, wherein converting the generated lithium sulfate (Li2SO4) into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) comprises removing contaminants from the lithium sulfate solution using single ion exchange purification.

18. The method of claim 9, wherein converting the generated lithium sulfate (Li2SO4) into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) comprises crystallizing lithium hydroxide (LiOH) using a single-stage crystallization.

19. The method according to claim 9, wherein generating lithium sulfate (Li2SO4) from the battery recycling process and converting the generated lithium sulfate (Li2SO4) into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) is performed in a closed system by recycling the sulfuric acid (H2SO4) into the battery recycling process.

20. The method of claim 9, further comprising recycling the generated lithium hydroxide (LiOH) back to at least one of a battery recycling process or a battery manufacturing process.

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