Method for treating sodium sulfate-containing residue process stream for battery process

Abstract

The present invention relates to a method for producing a potassium sulfate-containing fertilizer composition from a sodium sulfate-containing residue process stream of a battery production process or a battery recovery process wherein the residue process stream is provided from a battery production process or a battery recovery process, wherein the residue process stream is obtained from the production of batteries comprising at least sodium and iron (Na, Fe), or from the recovery of batteries comprising at least sodium and iron (Na, Fe); optionally providing water; providing potassium chloride; and providing and reacting a mixture comprising the optional water, potassium chloride and a residue process stream wherein potassium sulfate is obtained.

Description

Technical Field

[0001] The present invention relates to a method for providing a value-added product from a residual process stream from a battery production process. Background Art

[0002] The increased awareness of climate change and the limited supply of fossil fuels has driven the search for alternative energy sources for the operation of vehicles, for example. The demand for batteries is growing rapidly. This also means that emissions, solid and liquid residues from battery production increase. Therefore, recycling and material optimization have become relevant issues in recent years.

[0003] The battery manufacturing industry is constantly striving to minimize the supply of residuals and aims to recycle process essential chemicals like cobalt, lithium and manganese, which helps reduce the operating costs of the facility. Residues from the battery manufacturing process may be aqueous wastewater streams, ammonia, n-methylpyrrolidone and hazardous wastes such as battery metal components. However, since the residual streams, especially the wastewater streams, may be large in volume, it is desirable to reduce the amount of residuals and provide value-added components from streams classified as wastes to improve the overall operation of the battery manufacturing facility in terms of cost and raw material usage, and allow the reuse of the earth's limited resources. In addition, considering the residuals and discharges provided from the process, especially with regard to discharges to water receivers, local or national regulations may affect whether battery production is allowed. High levels of undesirable elements (like sulfates and sodium) may be provided in battery production, and they will have a negative impact on the residual process streams because their disposal costs are high, and if they are directly transferred to sewers and / or wastewater treatment plants, they will put a lot of pressure on the downstream processes, and the presence or presence of large amounts of sulfates and sodium may hinder the approval of permits to establish battery production facilities today. Sodium sulfate is a problematic byproduct for battery manufacturers to deal with. The costs for handling sodium sulfate can be significant given the volume of production, and not addressing chemical handling can prevent companies from getting the permits they need to continue their production or obtaining new permits for production increases or to build new production facilities.

[0004] Today, the sodium sulfate present in the residual process stream may be discharged, for example, to a wastewater system via drains or sewers, or discharged to a landfill or separated from the residual stream and sold as a low-grade chemical. Residual process streams from battery production facilities that contain sodium sulfate mainly originate from the oxidation step of cathode production. Even though sodium sulfate is considered a waste material, it may become a valuable asset if a use can be provided for it, since sodium sulfate may be present in large quantities. For battery manufacturing facilities, handling the obtained sodium sulfate is considered a problem. However, if the sodium sulfate can be fully utilized, it may become a value-added product in the overall process.

[0005] The problem with the current residual process streams at battery manufacturing facilities is that potentially valuable chemicals are not being recovered or recycled from them. In fact, large amounts of chemicals are always discharged to landfills, disposed of as low-grade chemicals, or sent to wastewater systems.

[0006] Today, there is also a greater focus on obtaining environmentally sustainable processes and obtaining as many value-added or recyclable products as possible from the processes in order to avoid as much waste and loss as possible.

[0007] Therefore, there is a need to obtain more efficient methods. There is a need for methods that reduce the need to place materials into landfills and discharge valuable chemicals into wastewater systems. There is also a need to provide additional value-added products from waste materials from battery production or recycling facilities, which improves the economics of the entire battery production or recycling facility. Summary of the invention

[0008] By means of the method of the invention, a high-value product can be obtained and at the same time a more environmentally sustainable solution for waste disposal is provided. By providing an added-value product that is in demand and can be sold on the market, the overall economics of a battery production or recycling facility is improved and nature's resources are used with care. Furthermore, the method enables the possibility of meeting requirements and regulations related to waste disposal from battery manufacturing.

[0009] By the present invention, a large amount of chemicals present in the residual process stream (i.e., sodium sulfate) can be used and the negative environmental impact from the battery residual process stream can be eliminated. Since a high grade fertilizer is obtained by the present invention, the nutritional chemicals can also be transferred to the plants that need them, rather than transferring them to the drain or sewer, or to a landfill or separated as a low grade chemical.

[0010] The scope of the invention is consistent with the following claims.

[0011] The present invention relates to a method for producing a fertilizer composition containing potassium sulfate, K2SO4, from a battery production process or a battery recycling process. The present invention relates to a method for producing a fertilizer composition containing potassium sulfate from a residual process stream containing sodium sulfate of a battery production process, wherein the residual process stream is provided from a battery production process, wherein the residual process stream is obtained from a battery containing at least sodium and iron (Na, Fe); optionally water is provided; potassium chloride is provided; and a mixture comprising the optional water, potassium chloride and the residual process stream is provided and reacted, wherein potassium sulfate is obtained. The present invention relates to a method for producing a fertilizer composition containing potassium sulfate from a residual process stream containing sodium sulfate of a battery production process or a recycling process, wherein the residual process stream is provided from a battery production process or a recycling process, wherein the residual process stream is obtained from the production of a battery containing at least sodium and iron (Na, Fe), or from the recycling of a battery containing at least sodium and iron (Na, Fe); optionally water is provided; potassium chloride is provided; and a mixture comprising the optional water, potassium chloride and the residual process stream is provided and reacted, wherein potassium sulfate is obtained. The residue process stream may be provided from a process in the production of a battery containing sodium and iron, and optionally cyanide, or may be provided from a recovery process of a battery containing sodium and iron, and optionally cyanide.

[0012] A method is provided for producing a fertilizer composition containing potassium sulfate from a residual process stream containing sodium sulfate of a battery production process, wherein:

[0013] The residual process stream is provided from a battery production process, wherein the residual process stream is obtained from a battery comprising at least sodium and iron (Na, Fe);

[0014] optionally providing water;

[0015] Providing potassium chloride; and

[0016] A mixture comprising the optional water, potassium chloride and a residual process stream is provided and reacted, wherein potassium sulfate is obtained. The cell may additionally contain cyanide.

[0017] According to one embodiment, potassium chloride and a residue process stream are provided in any order or simultaneously to provide the mixture. The optional water and residue process stream are preferably added before the potassium chloride.

[0018] According to one embodiment, an acid is mixed into the mixture. Preferably sulfuric acid and / or hydrochloric acid is used, more preferably sulfuric acid. Preferably the acid is added before the addition of potassium chloride. This addition may be done to adjust the pH of the mixture.

[0019] According to one embodiment, the residue process stream is contacted with potassium chloride.

[0020] According to one embodiment, sodium hydroxide and / or potassium hydroxide is added to the water, potassium chloride and residue process stream mixture. This is done to adjust the pH, for example if an acid has been added.

[0021] According to one embodiment, glauberite is obtained by reaction of water, potassium chloride and a residual process stream, the glauberite is removed and mixed with additional potassium chloride and / or leached with water to provide potassium sulfate. Potassium sulfate can then be removed for further use or sale. It should be noted that the mixing of potassium chloride and leaching with water can be carried out in any order. However, in a preferred embodiment, the reaction with potassium chloride is carried out first, followed by leaching with water.

[0022] According to one embodiment, the mixture remaining after removal of the potassium sulfate is concentrated, wherein after removal of any sodium chloride present, for further use.

[0023] According to one embodiment, the removed sodium chloride is forwarded to a tank membrane process where it is converted into sodium hydroxide, hydrogen and chlorine.

[0024] The invention also relates to the use of the method according to the invention for producing a fertilizer comprising potassium sulfate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A diagram outlining a process according to one embodiment of the present invention for producing potassium sulfate from Na2SO4 derived from the Prussian White production process is shown.

[0026] Figure 2 A block diagram of a process for producing cathode material is shown, along with the Na2SO4 residual waste stream generated in the production of Prussian White. DETAILED DESCRIPTION

[0027] The present invention is directed to providing valuable components from residual process streams produced by or recovered from sodium-iron batteries.

[0028] The process of the invention for producing a fertilizer composition containing potassium sulfate from a residual process stream containing sodium sulfate of a battery production process comprises the following steps:

[0029] The residual process stream is provided from a battery production process, wherein the residual process stream is obtained from the production of a battery comprising at least sodium and iron (Na, Fe);

[0030] optionally providing water;

[0031] Providing potassium chloride; and

[0032] A mixture comprising said optional water, potassium chloride and a residual process stream is provided and reacted, wherein potassium sulfate is obtained. Optionally, the cell further comprises cyanide.

[0033] The process of the invention for producing a fertilizer composition containing potassium sulfate from a residual process stream containing sodium sulfate of a battery recovery process comprises the following steps:

[0034] The residue process stream is provided from a battery recycling process, wherein the residue process stream is obtained from the recycling of batteries comprising at least sodium and iron (Na, Fe);

[0035] optionally providing water;

[0036] Providing potassium chloride; and

[0037] A mixture comprising said optional water, potassium chloride and a residual process stream is provided and reacted, wherein potassium sulfate is obtained. Optionally, the cell further comprises cyanide.

[0038] The residue process stream may be mixed with water and at least partially dissolved in water. Preferably the residue process stream is a solution. Preferably the components of the residue process stream are dissolved. The aqueous mixture of the residue process stream may optionally be treated with an acid, preferably sulfuric acid. The optional use of an acid may depend on the composition of the residue process stream.

[0039] The residual process stream may vary in chemical content and may contain the following impurities: Na2SO4, sodium, calcium, lithium, aluminum, iron and manganese. A subsequent step of pH adjustment using an alkaline compound may optionally be used, for example if the above-mentioned acids have been added in the process. Preferably KOH and / or NaOH are used as alkaline compounds. The addition of alkaline compounds can be used to increase the pH and achieve the correct stoichiometric relationship with respect to K2SO4 and NaCl.

[0040] Potassium chloride KCl is added to an aqueous mixture comprising a residual process stream in order to obtain potassium sulfate. The solid phase obtained in the process may comprise a salt called glauberite (K3Na(SO4)2) consisting of potassium sulfate and sodium sulfate. In one embodiment, the intermediate product obtained in the process of the invention after the first addition of potassium chloride is glauberite.

[0041] The obtained glauberite salt is removed from the treated residue process stream (liquid remainder of the mixture) and can be further treated with KCl to produce K2SO4. The obtained K2SO4 can thereafter be removed.

[0042] These reactions are used to produce the intermediates glauberite and K2SO4, which are disclosed below.

[0043] Glauber's Salt:

[0044] 6KCl+4Na2SO4→2K3Na(SO4)2+6NaCl

[0045] K2SO4:

[0046] 2KCl+2K3Na(SO4)2→4K2SO4+2NaCl

[0047] As an alternative treatment, the obtained glauberite salt can be leached in water after removal from the treated residue process stream to provide K2SO4.

[0048] However, in other embodiments, the method of the invention may comprise a combination of the two mentioned treatment steps for glauberite in any order. The glauberite salt obtained may then be first treated with KCl and thereafter leached in water to produce K2SO4, or vice versa.

[0049] The potassium chloride used in the method of the present invention can be subjected to a pretreatment step (including washing and optionally evaporation) before being added to the residue process stream. The pretreatment carried out by washing with water allows the removal of by-products or impurities present. The potassium chloride products provided on the market usually contain some by-products or impurities, such as sodium chloride. By subjecting potassium chloride to water washing, any impurities present can be removed from potassium chloride and the quality of the potassium chloride to be added to the residue process stream can be improved. By using water washing and optionally evaporating water for pretreatment, the quality of potassium chloride can be improved to contain up to 1wt% sodium chloride from containing about 4wt% sodium chloride, for example. When the conversion to potassium sulfate is carried out at a pH of about 5-9, such as about 6 to 8, and preferably about 6-7, this increase in the purity of the potassium chloride used in the method of the present invention increases the output of potassium sulfate obtained in the conversion step by at least five times.

[0050] The treated residual process stream remaining after separation of the K2SO4 can be further processed, for example by a cooling step in order to precipitate the sodium sulfate and increase the sulfate yield by returning the sulfate to the process.

[0051] The treated residue process stream remaining after separation of K2SO4 can be further processed, for example by evaporation to precipitate sodium chloride (NaCl), which can be removed as a solid phase. It can then be used, for example, as road salt.

[0052] The present invention can be further supplemented by using a membrane tank process that can convert the obtained NaCl into NaOH, H2 and Cl2. NaOH is a valuable chemical and is used by battery production and / or recycling plants. The two other products H2 and Cl2 can be collected and used as energy in the case of H2 or sold to third parties to improve the economics and profitability of the battery process.

[0053] In this way, value-added products beyond the fertilizer produced can be obtained and reused in the battery production process or other processes or sold.

Claims

1. A method for producing a fertilizer composition containing potassium sulfate from a residual process stream containing sodium sulfate of a battery production process or a battery recycling process, wherein: The residual process stream is provided from the battery production process or the battery recycling process, wherein the residual process stream is obtained from the production of batteries comprising at least sodium and iron (Na, Fe), or from the recycling of batteries comprising at least sodium and iron (Na, Fe); optionally providing water; Provide potassium chloride; as well as A mixture comprising said optional water, potassium chloride and a residual process stream is provided and reacted, wherein potassium sulfate is obtained.

2. The method according to claim 1, wherein: The residual process stream is obtained from the production of batteries containing sodium, iron and cyanide (Na, Fe, CN) or from the recovery of batteries containing sodium, iron and cyanide (Na, Fe, CN).

3. The method according to claim 1 or 2, wherein: The water, the potassium chloride and the residue process stream are mixed in any order or simultaneously to provide said mixture, preferably the water and residue process stream are added before the potassium chloride.

4. The method according to any one of claims 1 to 3, wherein: The acid is preferably mixed into the mixture prior to adding the potassium chloride.

5. The method according to any one of claims 1 to 4, wherein: The residue process stream has been pretreated in an evaporation step to produce a dry material which is contacted with the water and thereafter with the potassium chloride.

6. The method according to any one of claims 1 to 5, wherein: Sodium hydroxide and / or potassium hydroxide is added to the water, potassium chloride and residue process stream mixture.

7. The method according to any one of claims 1 to 6, wherein: Glauberite is obtained by reaction of the water, the potassium chloride and the residual process stream, which is removed and mixed with additional potassium chloride and / or leached with water to provide potassium sulfate.

8. The method according to claim 7, wherein: The mixture remaining after removal of the potassium sulfate is concentrated, followed by removal of any sodium chloride present.

9. The method according to claim 8, wherein: This removed sodium chloride is transferred to a cell membrane process where it is converted into sodium hydroxide, hydrogen and chlorine.

10. The method according to any one of claims 1 to 9, wherein: The potassium chloride added to the residue process stream has been subjected to a pretreatment step comprising washing with water and optionally subsequent evaporation to remove any impurities present in the potassium chloride.

11. Use of the method according to any one of claims 1 to 10 for producing a fertilizer comprising potassium sulfate.

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