METHOD FOR TREATMENT OF WASTEWATER GENERATED DURING SYNTHESIS OF BATTERY CATHODEODE MATERIAL PRECURSORS

Abstract

This patent application discloses a method for treating wastewater generated during the synthesis of a battery cathode material precursor, and belongs to the field of wastewater treatment engineering. The method includes: subjecting wastewater generated during the synthesis of a battery cathode material precursor to impurity removal and concentration to obtain a concentrate, making the concentrate into a suspension, and subjecting the suspension to a solid-liquid separation (SLS) to obtain a first de-alkalized mother liquor; removing sodium bicarbonate in the first de-alkalized mother liquor to obtain a second de-alkalized mother liquor; and subjecting the second de-alkalized mother liquor to evaporative crystallization to obtain an ammonium nitrogen fertilizer primarily including ammonium sulfate.This method can increase the conversion rate of sodium sulfate, and allows the sodium sulfate produced during the synthesis of battery cathode material precursors to be used effectively while avoiding the formation of solid waste.

Description

METHODS FOR TREATMENT OF WASTEWATER GENERATED DURING SYNTHESIS BATTERY CATHODEOSE PRECURSOR MATERIAL Invention Engineering Field This patent application relates to the field of engineering wastewater treatment for cathode material precursor synthesis batteries, and specifically relates to methods for treat wastewater generated during precursor synthesis battery cathode material. Background of the Invention During the production process of cathode material precursors for batteries lithium-ion battery (LIB) / sodium ion battery (sodium-ion battery (SIB)), a large amount of wastewater that containing sodium sulfate will be produced in the procedure sedimentation: and wastewater generated during synthesis further ternary and multi-element precursors include ammonia. According to the chemical reaction formula, it is estimated that 1.53 tons of sodium sulfate will be produced in the production of each ton ternary lithium ion battery (LIB) / sodium ion battery (SIB) and multi-element ternary cathode material precursor, and about 1.41 tons sodium sulfate will be produced in the production of each ton of ferrite phosphate precursor cathode material lithium iron phosphate (LFP) batteries lithium ion (LIB). With the increasingly rapid development of the lithium ion industry electronics and new energy vehicle industry, the number of shipments ternary precursors reached 618,000 tons and the number of ferry shipments phosphate reached about 330,000 tons in China in 2021, and therefore, approximately 1.41 million tons of sodium sulfate produced in 2021. It is estimated that the total number of sodium sulfate produced in the precursor industry will exceed 5 million tonnes by 2025. Several methods for treating the wastewater produced during the production of lithium ion battery (LIB) cathode material precursors / sodium ion battery (SIB) in the prior art has problems such as high evaporation energy consumption and massive accumulation of sodium sulfate, and in some methods in the prior art, sodium sulfate in the wastewater of ferrous phosphate is converted to the by-product phosphogypsum, which causing excessive amounts of solid waste, and not economical and environmentally friendly. In addition, the method for treat wastewater generated during precursor synthesis provided in the prior art relates to the rate of low sodium sulfate conversion, which is around 758. In view of this, this patent application is proposed special. Brief Description of the Invention The purpose of this patent application is to provide a method for treating wastewater produced during synthesis of precursors for battery cathode materials. This method can increase the conversion rate of sodium sulfate, and allow sodium sulfate by-product produced during the synthesis precursors of battery cathode materials can be used effectively in downstream while avoiding the formation of solid waste, so that avoid problems such as pollution and environmental damage. This patent application can be implemented as following: This patent application provides a method for treat wastewater generated during precursor synthesis battery cathode material, includes the following steps: Sl: removes wastewater impurities containing sodium sulfate and is produced during the synthesis of precursor materials battery cathode to obtain sodium sulfate solution, S2: concentrate sodium sulfate solution to obtain sodium sulfate concentrate: S3: make sodium sulfate concentrate into a suspension that contains sodium bicarbonate: S4: wearing a suspension containing sodium bicarbonate with solid-liquid separation (SLS) to obtain the first wet product of sodium bicarbonate and first mother liquor from which alkali is removed: S5: concentrates the first mother liquor removed alkali to obtain concentrated mother liquor, using liquid concentrated parent stock with cooling crystallization to precipitate some sodium bicarbonate, and put on a system that produced by solid-liquid separation (SLS) for obtain the second wet product of sodium bicarbonate and liquid the second parent from which the alkali is removed, and S6: wearing the second removed mother liquor alkali by evaporative crystallization to obtain fertilizer Ammonium nitrogen mainly includes ammonium sulfate. In an optional embodiment example, when the precursor material battery cathodes are precursors to ternary cathode materials and / or multi-element cathode material precursors, S1 includes: remove ammonia from wastewater containing ammonia and sodium sulfate and are produced during precursor synthesis battery cathode material to obtain waste liquid remove ammonia, and remove metal hydroxide residues in wastewater from which ammonia is removed to obtain sodium sulfate solution is free from ammonia and heavy metal ions. In an optional embodiment example, the method further includes: condensing and absorbing evaporated ammonia gas during the removal of ammonia to make ammonium hydroxide, and return ammonium hydroxide to the synthesis procedure. In an optional embodiment example, when the precursor material battery cathode is a precursor to lithium iron phosphate cathode material (LFP), S1 includes: removing phosphate ions from wastewater which contains phosphate and sodium sulfate ions and is produced during the synthesis of battery cathode material precursors to obtain sodium sulfate solution from which phosphorus has been removed. In an optional embodiment example, the sodium sulfate solution which has had its phosphorus removed is obtained through the process as follows: following: mixing the wastewater to be treated with suspension calcium sulfate, and removes calcium phosphate deposits that produced to obtain a solution containing 10on calcium: and mix the solution containing calcium ions with the solution sodium carbonate, and removes calcium carbonate deposits produced to obtain a sodium sulfate solution phosphorus removed. In an optional embodiment example, the mass concentration of sodium sulfate in sodium sulfate concentrate obtained in S2 not less than 30 g / L. In an optional embodiment example, sodium sulfate concentrate is a nearly saturated solution of sodium sulfate or sodium hydroxide solution saturated sulfate. In an optional embodiment example, the resulting pure water during the concentration of the sodium sulfate solution is returned to the procedure precursor synthesis front end. In an optional embodiment example, in S3, the suspension containing sodium bicarbonate obtained by mixing sodium sulfate concentrate with ammonium bicarbonate, or, suspension containing sodium bicarbonate is obtained by mixing sodium sulfate concentrate with ammonium hydroxide and carbon dioxide. In an optional embodiment example, the weight ratio of sodium sulfate concentrate to ammonium bicarbonate is (1- 1,2):1. In an optional embodiment example, sodium sulfate concentrate and ammonium bicarbonate are mixed under stirring. In an optional embodiment, stirring is performed at stirring speed 120 rpm to 600 rpm, and / or, stirring is carried out for no less than 60 minutes. In an optional embodiment example, in S5, the mother liquor concentrated after cooling has a temperature not higher than 20”C. In an optional embodiment example, the method further includes SYA: drying wet products sodium bicarbonate first and / or second sodium bicarbonate wet product for later use. In an optional embodiment example, the method further includes S7B: calcining wet product of sodium bicarbonate first and / or second sodium bicarbonate wet product for obtain sodium carbonate products. In an optional embodiment example, the calcination is carried out at 140”cC to 210”C: and / or, calcination is carried out not less than from 30 minutes. This patent application has the beneficial effect of following: In this patent application, wastewater containing sodium sulfate and is produced during the synthesis of precursor materials battery cathodes are subjected to impurity removal and concentration to obtain sodium sulfate concentrate directly which can be used for the manufacture of alkali, and sodium concentrate sulfate is made into a suspension containing sodium bicarbonate, and suspensions containing sodium bicarbonate further made into soda ash and ammonium nitrogen fertilizer, so that sodium sulfate in wastewater and ammonium raw materials bicarbonate is converted to high-value sodium carbonate and high-value ammonium nitrogen fertilizer, which brings benefits huge economic benefits for precursor manufacturers while solves the dilemma that precursor manufacturers hoard sodium sulfate in large quantities, and provides a method of water treatment waste that is suitable for the cathode material precursor production industry lithium ion battery (LIB) / sodium ion battery (SIB). In addition, in this patent application, through two concentration, most of the water is separated, which reduces subsequent evaporative crystallization energy consumption to make ammonium nitrogen fertilizer: and the mother liquor removed the resulting alkali is subjected to evaporative crystallization directly to produce ammonium nitrogen fertilizer mainly includes ammonium sulfate, which realizes full utilization of nitrogen in the raw materials. During the manufacture alkali, the first mother liquor from which the alkali is removed further concentrated with a membrane filtration system, which increase the yield of sodium bicarbonate and the rate of sodium conversion sulfate, and the conversion rate of sodium sulfate can reach 858 or higher. Short Description of Image To explain the engineering solution in an example embodiment from this patent application clearly, the attached drawings required in this example embodiment is described in detail briefly below. It should be understood that, the images The following attachments only show some examples of the embodiment of this patent application, and thus may not considered as a limitation on the scope of this patent application. Those who are experts in this field still are can get other related accompanying images from these accompanying images without any creative effort. Figure 1 is a flow chart of the first process of the method. to treat wastewater generated during synthesis battery cathode material precursors provided in the application this patent: and Figure 2 is a flow chart of the second process of the method for treat wastewater generated during precursor synthesis battery cathode materials provided in this patent application. Complete Description of the Invention To establish the objectives, technical solutions, and benefits of example of the embodiment of this patent application becomes clear, the solution techniques in the example embodiments of this patent application will explained clearly and completely below. If there is no special conditions specified in the example embodiments, for example This embodiment will be implemented under conventional conditions. or conditions recommended by the manufacturer. All reagents or instruments used that are not specified by manufacturers are conventional products that are available commercially. commercial. Methods for treating wastewater generated during synthesis of precursors for battery cathode materials provided by This patent application is specifically described below. As shown in Figure 1 and Figure 2, This patent application provides a method for treating water waste generated during the synthesis of cathode material precursors battery, includes the following steps: Sl: Impurities are removed from wastewater containing sodium sulfate and is produced during the synthesis of precursor materials battery cathode to obtain sodium sulfate solution. The battery cathode material can be an ion battery cathode material. lithium (LIB) or sodium ion battery (SIB) cathode material. The cathode material precursor can be a cathode material precursor ternary or multi-element cathode material precursors, or can in the form of a precursor to lithium iron phosphate (LFP) cathode material (such as ferric phosphate). In some examples of optional embodiments, such as those shown in Figure 1, when the cathode material precursor batteries are precursors to ternary cathode materials and / or precursors multi-element cathode materials, S1 thus includes: ammonia is removed from wastewater containing ammonia and sodium sulfate and are produced during precursor synthesis battery cathode material to obtain waste liquid ammonia is removed, and metal hydroxide residues in the liquid waste from which ammonia is removed is removed to obtain sodium sulfate solution free of ammonia and heavy metal ions. The above process can be carried out in a rectification tower. Furthermore, after the removal of ammonia, the ammonia gas that evaporated during ammonia removal is condensed and absorbed (for example, evaporated ammonia gas is condensed and absorbed by the condenser at the top of the rectification tower) for make ammonium hydroxide, and the ammonium hydroxide is returned to the synthesis procedure. The waste liquid from which the ammonia is removed is obtained after removal of ammonia can be excreted through the section bottom of the rectification tower, subject to heat exchange, and then filtered to remove residual metal hydroxide (where metals may include, for example, nickel, cobalt, manganese, and / or iron) which is precipitated due to the removal of ammonia for obtain a sodium sulfate solution that is free from ammonia and ions heavy metal. It should be noted that the specific molecular formula of the precursor the above-mentioned ternary cathode materials and / or precursors multi-element cathode materials may refer to prior art, which is not specifically defined here. In some other optional embodiment examples, such as shown in Figure 2, the precursor of battery cathode material is a precursor to lithium iron phosphate (LEFP) cathode material (precursor is for solution to precipitate ferric phosphate with sodium phosphate), and Sl thus includes: phosphate ions are removed from wastewater containing ions phosphate and sodium sulfate and are produced during the synthesis precursor of battery cathode material to obtain sodium solution sulfate that has had its phosphorus removed. In particular, the sodium sulfate solution is removed The phosphor can be obtained through the following process: waste stream to be processed is mixed with suspension calcium sulfate resulting in excessive phosphate ions in the water waste is precipitated in the form of calcium phosphate, and the sediment the calcium phosphate produced is then removed (e.g., calcium phosphate deposits can be removed by filtration): and the solution containing calcium ions obtained after calcium phosphate precipitate is removed by mixing with a solution sodium carbonate to precipitate excess calcium ions in the form of calcium carbonate, and calcium carbonate precipitates produced is further removed (e.g., calcium deposits carbonate can be removed by filtration) to obtain sodium sulfate solution from which phosphorus has been removed. In some other optional embodiments, water waste generated during the synthesis of cathode material precursors battery includes at least two selected from the cluster which consists of wastewater produced during synthesis precursor of ternary cathode material, wastewater generated during synthesis of multi-element cathode material precursors, and wastewater produced during the synthesis of lithium cathode material precursors iron phosphate (LFP), and in this case, different types of Each waste stream is processed according to Sl for precursors different battery cathode materials, and then a sodium solution The resulting sulfates are combined for the next step. S2: Sodium sulfate solution is concentrated to obtain sodium sulfate concentrate (which can be used for the manufacture of alkali). For example, this step can be done with the system membrane filtration, which is not limited to it. For reference, the mass concentration of sodium sulfate in sodium sulfate concentrate not less than 30 g / L, such as 30.4 g / L, 32 g / L, 35.5 g / L, or 47.6 g / L. Preferably, sodium sulfate concentrate is a solution nearly saturated sodium sulfate or sodium sulfate solution saturated, which facilitates an increase in the rate of sodium conversion sulfate. Furthermore, pure water is produced during concentration. sodium sulfate solution can also be returned to the end procedure front of precursor synthesis. S3: Sodium sulfate concentrate is made into a suspension which contains sodium bicarbonate. This step can be done in a reactor. In some exemplary embodiments, a suspension containing Sodium bicarbonate can be obtained by mixing concentrate sodium sulfate with ammonium bicarbonate. In some examples another embodiment, a suspension containing sodium bicarbonate can also be obtained by mixing sodium concentrate sulfate with ammonium hydroxide and carbon dioxide. For reference, the weight ratio of sodium concentrate sulfate to ammonium bicarbonate can be (1-1,2):1, such as 1l:l, 1.05:1, 1.08:1, 1.1l:1, 1.12:1, 1.15:1, 1.2:1, or other values in the range (1-1.2):1. Preferably, sodium sulfate and ammonium concentrate bicarbonate is mixed under stirring, so that both can react quickly and uniformly. For example, stirring can be done at a speed stirring 120 rpm to 600 rpm (more preferably 400 rev / min): and preferably stirring can be done done in no less than 60 minutes. S4: Suspension containing sodium bicarbonate is applied solid-liquid separation (SLS) to obtain wet products the first sodium bicarbonate and the first mother liquor that de-alkali (i.e., mother liquor I de-alkali) alkali in Figure 1). For reference, solid-liquid separation (SLS) can be carried out in a vacuum filter. After solid-liquid separation (SLS) is complete, the resulting solid can also be washed. S5: The first mother liquor that has had its alkali removed concentrated to obtain concentrated mother liquor, mother liquor This concentrate is subjected to cooling crystallization to precipitate some sodium bicarbonate, and the resulting system subjected to solid-liquid separation (SLS) to obtain the product second wet sodium bicarbonate and second mother liquor which de-alkali (i.e., mother liquor II de-alkali) alkali in Figure 1). In this step, concentration is carried out using the system membrane filtration. For example, the first mother liquor is de-alkalised can be concentrated until the resulting concentrate volume is 458, 508, or 628 volumes of sodium sulfate solution added. Preferably, the mother liquor is concentrated after cooling. have a temperature not higher than 20”C, such as 20”C, 18”c, 15”C, 12”C, 10”C, or 9C. Temperature control of the cooled concentrated mother liquor can be make the concentration of mother liquor I which has had its alkali removed approaching saturation concentration to increase the conversion rate sodium, and can also effectively control the concentration ammonium sulfate to avoid synchronous precipitation of ammonium sulfate and the introduction of ammonium sulfate into sodium bicarbonate which is deposited. S6: The second mother liquor with the alkali removed is subjected to evaporative crystallization to obtain ammonium nitrogen fertilizer especially those that include ammonium sulfate (which is available for for sale). In some exemplary embodiments, methods for treating water waste generated during the synthesis of cathode material precursors further batteries include STA: sodium wet product first bicarbonate and / or sodium bicarbonate wet product both are dried for later use (which is available for for sale). In some other exemplary embodiments, methods for treat wastewater generated during precursor synthesis battery cathode materials further include S1B: wet products first sodium bicarbonate and / or sodium wet product The second bicarbonate is calcined to obtain the sodium product carbonate (which is available for sale). For example, calcination can be carried out at 140”C to 210”C (such as 140”C, 150”C, 180”C, 200”C, or 210”C, and more preferably 160”C): and / or, calcination can be done as long as it does not less than 30 minutes (such as 30 minutes, 60 minutes, or 90 minutes, and preferably 65 minutes). It should be noted that, according to actual needs, some of the first wet sodium bicarbonate products can be used for S7A and the remaining part of the sodium wet product bicarbonate can first be used for S7 / B, and similarly, some of the second wet product of sodium bicarbonate can be used for S7A and the remaining part of the sodium wet product The second bicarbonate can be used for S / B: and wet products The first sodium bicarbonate can be used entirely for S7A and the second sodium bicarbonate wet product can be used entirely for S7B, and likewise, the sodium wet product the second bicarbonate can be used entirely for S7 / A and products The first wet sodium bicarbonate can be used entirely for S / B. In short, in the method for treating wastewater that produced during the synthesis of precursors for battery cathode materials. provided by this patent application, wastewater is subject to removal of impurities and membrane concentration to obtain sodium sulfate concentrate directly that can be used for the manufacture of alkali: and sodium sulfate concentrate is made into a suspension containing sodium bicarbonate, and a suspension containing sodium bicarbonate was further prepared into soda ash and ammonium nitrogen fertilizer, so that sodium sulfate in wastewater and raw material ammonium bicarbonate converted into high-value sodium carbonate and fertilizer high-value ammonium nitrogen, which brings economic benefits which is huge for precursor manufacturers while solving the dilemma that precursor manufacturers stockpile sodium sulfate in Large quantities, and provide a method of wastewater treatment. suitable for the industrial production of cathode material precursors lithium ion battery (LIB) / sodium ion battery (SIB). In addition, in this patent application, through two concentration of wastewater and residual mother liquor from manufacturing alkali by membrane filtration system, most of the water separated, which reduces the energy consumption of crystallization. the next evaporative to make ammonium nitrogen fertilizer: and the resulting mother liquor from which the alkali is removed subjected to direct evaporative crystallization for producing ammonium nitrogen fertilizers mainly including ammonium sulfate, which realizes the full utilization of nitrogen in raw materials. During the manufacture of alkali, the first mother liquor that removed alkali further concentrated with the system membrane filtration, which increases the yield of sodium bicarbonate and sodium sulfate conversion rate, and sodium sulfate conversion rate can reach 858 or higher. Features and properties of this patent application explained further in detail below along with example of embodiment. Example of Embodiment 1 As shown in FIG. 1, in an example embodiment This is a method for treating the wastewater produced during the synthesis of lithium ion battery (LIB) cathode material precursors provided, includes the following steps: Sl: Wastewater (includes ammonia, sodium sulfate, nickel, cobalt, and manganese) produced during the synthesis of nickel- cobalt-manganese hydroxide (precursor of ion battery cathode material) lithium (LIB)) is fed directly into the tower rectification and subject to removal of ammonia, the ammonia gas evaporated condensed and absorbed by the condenser in the section top of the tower to obtain ammonium hydroxide, and ammonium hydroxide is returned to the synthesis procedure, and the waste liquid which has its ammonia removed at the bottom of the tower is subjected to heat exchange with waste water and then filtered to remove the resulting sediment (which is deposited mainly in the form of nickel, cobalt, and manganese hydroxides in state complex due to the removal of ammonia) to obtain a solution sodium sulfate which is free from ammonia and heavy metal ions. S2: Sodium sulfate solution obtained above concentrated with a membrane filtration system to obtain sodium sulfate concentrate (where the mass concentration of sodium sulfate is 47.6 g / L) and pure water, and the pure water is returned to the front-end procedure of precursor synthesis. S3: Sodium sulfate concentrate obtained above added together with ammonium bicarbonate to the reactor to obtain a suspension containing sodium bicarbonate, where is the mass ratio of sodium sulfate concentrate to ammonium bicarbonate is about 1.12:1:7 and stirring is done at stirring speed 250 rpm for 120 minutes. S4: Suspension containing sodium bicarbonate is applied solid-liquid separation (SLS) with vacuum filter and washing to obtain the first wet product of sodium bicarbonate and the first mother liquor from which the alkali is removed (i.e., the mother liquor parent I from which the alkali is removed). S5: The first mother liquor that has had its alkali removed concentrated with a membrane filtration system to obtain concentrated mother liquor (the first mother liquor removed) The alkali is concentrated to a volume of concentrated mother liquor that The volume of sodium sulfate solution produced is 628 added), the concentrated mother liquor is subjected to crystallization cooling to obtain a concentrate with sodium precipitate bicarbonate, and the concentrate is subjected to solid-liquid separation (SLS) with vacuum filter and washing to obtain the product second wet sodium bicarbonate and second mother liquor which de-alkali (i.e., mother liquor II de-alkali) alkali), where the concentrated mother liquor after cooling has a temperature 10”C and ammonium sulfate concentration of about 71.4 g / L. S6: The second mother liquor from which the alkali is removed obtained above was subjected to evaporative crystallization to obtaining ammonium nitrogen fertilizer mainly includes ammonium sulfate. S7: First wet product of sodium bicarbonate and product The second wet sodium bicarbonate obtained above each each calcined (calcination temperature: 200”C, and calcination time: 30 minutes) to make sodium carbonate products for sale: or, the first wet product of sodium bicarbonate and the wet product the second sodium bicarbonate is dried and then immediately for sale. It has been calculated that the conversion rate of sodium sulfate According to this method it is around 8885. Example of Embodiment 2 As shown in FIG. 2, in an example embodiment This is a method for treating the wastewater produced during the synthesis of precursors for lithium ion battery (LIB) cathode materials provided, includes the following steps: Sl: Wastewater (including sodium sulfate and sodium phosphate) produced during the synthesis of ferric phosphate (a precursor to lithium ion battery (LIB) cathode is added to the suspension calcium sulfate in appropriate quantities so that sodium phosphate reacts with calcium sulfate to produce calcium precipitate phosphate, and the sediment is removed by filtration, and then sodium carbonate solution in appropriate amount is added so that excess calcium ions are precipitated into calcium carbonate, and then the resulting calcium carbonate precipitate removed by filtration to obtain a sodium solution phosphorus-reduced sulfate. S2: Sodium sulfate solution obtained above concentrated with a membrane filtration system to obtain sodium sulfate concentrate (where the mass concentration of sodium sulfate is 35.5 g / L) and pure water, and the pure water is returned to the front-end procedure of precursor synthesis. S3: Sodium sulfate concentrate obtained above added together with ammonium bicarbonate to the reactor to obtain a suspension containing sodium bicarbonate, where is the mass ratio of sodium sulfate concentrate to ammonium bicarbonate is about 1.08:1: and stirring is done at stirring speed 600 rpm for 60 minutes. S4: Suspension containing sodium bicarbonate is applied solid-liquid separation (SLS) with vacuum filter and washing to obtain the first wet product of sodium bicarbonate and the first mother liquor from which the alkali is removed (i.e., the mother liquor parent I from which the alkali is removed). S5: The first mother liquor that has had its alkali removed concentrated with a membrane filtration system to obtain concentrated mother liquor (the first mother liquor removed) The alkali is concentrated to a volume of concentrated mother liquor that The volume of sodium sulfate solution produced is 458 added), the concentrated mother liquor is subjected to crystallization cooling to obtain a concentrate with sodium precipitate bicarbonate, and the concentrate is subjected to solid-liquid separation (SLS) with vacuum filter and washing to obtain the product second wet sodium bicarbonate and second mother liquor which de-alkali (i.e., mother liquor II de-alkali) alkali), where the concentrated mother liquor after cooling has a temperature 20”C and ammonium sulfate concentration of about 73.4 g / L. S6: The second mother liquor from which the alkali is removed obtained above was subjected to evaporative crystallization to obtaining ammonium nitrogen fertilizer mainly includes ammonium sulfate. S7: First wet product of sodium bicarbonate and product The second wet sodium bicarbonate obtained above each each calcined (calcination temperature: 190”C, and calcination time: 40 minutes) to make sodium carbonate products for sale: or, the first wet product of sodium bicarbonate and the wet product the second sodium bicarbonate is dried and then immediately for sale. It has been calculated that the conversion rate of sodium sulfate According to this method it is around 878. Example of Embodiment 3 As shown in FIG. 1, in an example embodiment Here, a method is provided to treat wastewater which produced during the synthesis of precursors for ion battery cathode materials sodium (SIB), includes the following steps: Sl: Wastewater (includes ammonia, sodium sulfate, nickel, iron, and manganese) produced during the synthesis of nickel-iron- manganese hydroxide (precursor of sodium ion battery cathode material) (SIB)) is inserted directly into the rectification tower and subjected to ammonia removal, ammonia gas evaporates condensed and absorbed by the condenser at the top tower to obtain ammonium hydroxide, and ammonium hydroxide is returned to the synthesis procedure, and the waste liquid which has its ammonia removed at the bottom of the tower is subjected to heat exchange with waste water and then filtered to remove the resulting sediment (which is deposited mainly in the form of hydroxides of nickel, iron, and manganese in complex state due to the removal of ammonia) to obtain sodium sulfate solution free of ammonia and metal ions heavy. S2: Sodium sulfate solution obtained above concentrated with a membrane filtration system to obtain sodium sulfate concentrate (where the mass concentration of sodium sulfate is 30.4 g / L) and pure water, and the pure water returned to the precursor synthesis front-end procedure. S3: Sodium sulfate concentrate obtained above added together with ammonium bicarbonate into reactor to obtain a suspension containing sodium bicarbonate, where the mass ratio of sodium sulfate concentrate to ammonium bicarbonate is about 1.10:1j: and stirring is done at a stirring speed of 150 revolutions / minute for 180 minutes. S4: Suspension containing sodium bicarbonate is applied solid-liquid separation (SLS) with vacuum filter and washing to obtain the first wet product of sodium bicarbonate and the first mother liquor from which the alkali is removed (i.e., the mother liquor parent I from which the alkali is removed). S5: The first mother liquor that has had its alkali removed concentrated with a membrane filtration system to obtain concentrated mother liquor (the first mother liquor removed) The alkali is concentrated to a volume of concentrated mother liquor that The volume of sodium sulfate solution produced is 508 added), the concentrated mother liquor is subjected to crystallization cooling to obtain a concentrate with sodium precipitate bicarbonate, and the concentrate is subjected to solid-liquid separation (SLS) with vacuum filter and washing to obtain the product second wet sodium bicarbonate and second mother liquor which de-alkali (i.e., mother liquor II de-alkali) alkali), where the concentrated mother liquor after cooling has a temperature 99C and ammonium sulfate concentration of about 56.5 Y / L. S6: The second mother liquor from which the alkali is removed obtained above was subjected to evaporative crystallization to obtaining ammonium nitrogen fertilizer mainly includes ammonium sulfate. S7: First wet product of sodium bicarbonate and product The second wet sodium bicarbonate obtained above each each calcined (calcination temperature: 17 / 589C, and calcination time: 50 minutes) to make sodium carbonate products for sale: or, the first wet product of sodium bicarbonate and the wet product the second sodium bicarbonate is dried and then immediately for sale. It has been calculated that the conversion rate of sodium sulfate is According to this method it is around 8585. In short, the method for treating wastewater is produced during the synthesis of precursors for battery cathode materials. provided by this patent application may increase the rate conversion of sodium sulfate, and allows for by-products sodium sulfate is produced during the synthesis of cathode material precursors batteries to be utilized effectively downstream while avoid the formation of solid waste, thus avoiding problems such as pollution and environmental damage. The above is just an example of a preferred embodiment of this patent application, and is not intended to limit this patent application, and various changes and modifications can be carried out by those who are experts in this field this patent application. Any modification, equivalent substitution, improvements, or the like made in the spirit and the principles of this patent application will fall within the scope protection of this patent application.

Claims

1. A method for treating the wastewater produced during the synthesis of battery cathode material precursors, which include the following steps: Sl: removes impurities from wastewater containing sodium sulfate and is produced during the synthesis of precursor materials battery cathode to obtain sodium sulfate solution, S2: concentrate sodium sulfate solution to obtain sodium sulfate concentrate: S3: make sodium sulfate concentrate into a suspension that contains sodium bicarbonate: S4: wearing a suspension containing sodium bicarbonate with solid-liquid separation (SLS) to obtain the first wet product of sodium bicarbonate and first mother liquor from which alkali is removed: S5: concentrates the first mother liquor removed alkali to obtain concentrated mother liquor, using liquid concentrated parent stock with cooling crystallization to precipitate some sodium bicarbonate, and put on a system that produced by solid-liquid separation (SLS) for obtain the second wet product of sodium bicarbonate and liquid the second parent from which the alkali is removed, and S6: wearing the second removed mother liquor alkali by evaporative crystallization to obtain fertilizer Ammonium nitrogen mainly includes ammonium sulfate.

2. Methods for treating wastewater produced during synthesis of a battery cathode material precursor according to claim 1, where when the precursor of the battery cathode material is a precursor ternary cathode materials and / or precursors of multi- cathode materials elements, Sl includes: remove ammonia from wastewater containing ammonia and sodium sulfate and are produced during precursor synthesis battery cathode material to obtain waste liquid ammonia removed, and remove metal hydroxide residues in wastewater which has its ammonia removed to obtain a sodium solution sulfate that is free from ammonia and heavy metal ions.

3. Methods for treating wastewater produced during synthesis of a battery cathode material precursor according to claim 2, further includes: condensing and absorbing ammonia gas which evaporates during the removal of ammonia to make ammonium hydroxide, and return ammonium hydroxide to the synthesis precursor to battery cathode materials.

4. Methods for treating wastewater produced during synthesis of a battery cathode material precursor according to claim 1, where when the precursor of the battery cathode material is a precursor lithium iron phosphate (LFP) cathode material, S1 covers: removing phosphate ions from wastewater contains phosphate ions and sodium sulfate produced during synthesis of precursors for battery cathode materials to obtain solutions phosphorus-reduced sodium sulfate.

5. Methods for treating wastewater produced during synthesis of a battery cathode material precursor according to claim 4, where the sodium sulfate solution has had its phosphorus removed obtained through the following process: mixing the wastewater to be treated with suspension calcium sulfate, remove the calcium phosphate deposits produced to obtain a solution containing calcium ions: mixing a solution containing calcium ions with sodium carbonate solution, and remove the resulting calcium carbonate deposits to obtain a solution of sodium sulfate which is removed the phosphor.

6. Methods for treating wastewater produced during synthesis of precursors for battery cathode materials according to one of the claims of claims 1 to 5, wherein the mass concentration of sodium sulfate in sodium sulfate concentrate obtained in S2 not less than 30 g / Lj preferably, sodium sulfate concentrate is a solution saturated sodium sulfate: and preferably, pure water produced during concentration sodium sulfate solution is returned to the front end procedure from synthesis of ternary cathode material precursors.

1. Methods for treating wastewater produced during synthesis of a battery cathode material precursor according to claim 6, where in S3, the suspension contains sodium bicarbonate obtained by mixing sodium sulfate concentrate with ammonium bicarbonate, or, a suspension containing sodium bicarbonate is obtained by mixing sodium concentrate sulfate with ammonium hydroxide and carbon dioxide, preferably, the weight ratio of sodium sulfate concentrate to ammonium bicarbonate is (1-1,2):1j: preferably, sodium sulfate and ammonium concentrate bicarbonate mixed under stirring: and preferably, stirring is done at high speed stirring 120 rpm to 600 rpm, and / or, stirring is carried out for no less than 60 minutes.

8. Methods for treating wastewater produced during synthesis of precursors for battery cathode materials according to one of the claims of claims 1 to 5, wherein in S5, the mother liquor is concentrated after cooling has a temperature not higher than from 20”C. 9, Methods for treating wastewater generated during synthesis of precursors for battery cathode materials according to one of the claims from claims 1 to 5, further including S7TA: drying the first wet product of sodium bicarbonate and / or second use sodium bicarbonate wet product Later.

10. Methods for treating wastewater generated during synthesis of precursors for battery cathode materials according to one of the claims from claims 1 to 5, further including S7B: calcining the first wet product of sodium bicarbonate and / or a second sodium bicarbonate wet product to obtain sodium carbonate products, where preferred, calcination is carried out at 140”Cc to 210”C: and / or, calcination is carried out for not less than 30 minute.

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