Resourceful treatment process for production waste liquid of sodium-ion battery positive electrode material precursor

Abstract

The invention discloses a resourceful treatment process for production waste liquid of a sodium-ion battery positive electrode material precursor, and belongs to the technical field of water treatment. The method comprises the following steps: rectifying the production waste liquid of the positive electrode material precursor of the sodium-ion battery to convert ammonia water in the waste liquid into volatile substance ammonia gas, and recovering the volatile substance ammonia gas by combining two-stage absorption treatment; particles in the waste liquid are reduced through physical adsorption, and insoluble suspended pollutants in the waste liquid are separated and recovered through multiple times of filtration; finally, a proper precipitator is selected for precipitating SO4 < 2-> in the waste liquid, so that the purpose of recovering SO4 < 2-> is achieved. NH < 4 + > generated in the precipitation process is recycled in a crystallization mode. According to the method disclosed by the invention, the concentration of polluting zwitterions and cations in the waste liquid is reduced, high-value byproducts are obtained, sulfate radicals in the production waste liquid of the sodium-ion battery positive electrode material precursor are effectively recovered, and meanwhile, no wastewater is discharged.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and particularly relates to a resource treatment process for the waste liquid produced in the production of the precursor of the positive electrode material of a sodium-ion battery. Background Art

[0002] Currently, in the industrial production process of the precursor of the positive electrode material of a sodium-ion battery, the co-precipitation method is generally used to synthesize the nickel-iron-manganese ternary precursor. The waste liquid produced by this process mainly contains ammonium sulfate, unreacted metal sulfates (such as MnSO 4 , FeSO 4 , NiSO 4 ) and trace amounts of ammonia water and other pollutants. The traditional treatment process has the following defects: (1) End-of-pipe treatment relies on the coagulation-precipitation process, and coagulants such as polyaluminum chloride (PAC) need to be added, resulting in high treatment costs and the generation of secondary sludge; (2) The sulfate radical resources in the waste liquid are not effectively recovered, causing resource waste; (3) It is difficult for the ion concentration in the treated effluent to stably meet the requirements of Class IV limit values in the "Groundwater Quality Standard" (GB / T 14848-2017); (4) When using the calcium hydroxide precipitation method to treat sulfate wastewater, although calcium sulfate precipitation can be generated, the residual calcium ions are likely to cause pipeline scaling, and the purity of calcium sulfate is low and it is difficult to be recycled.

[0003] Therefore, there is an urgent need for a resource treatment process for the waste liquid produced in the production of the precursor of the positive electrode material of a sodium-ion battery that can effectively recover sulfate radicals and has no wastewater discharge. Summary of the Invention

[0004] To solve the above technical problems, the present invention proposes a resource treatment process for the waste liquid produced in the production of the precursor of the positive electrode material of a sodium-ion battery.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a resource treatment process for the waste liquid produced in the production of the precursor of the positive electrode material of a sodium-ion battery, including the following steps:

[0007] (1) Detect the composition of the waste liquid produced in the production of the precursor of the positive electrode material of a sodium-ion battery;

[0008] (2) Subject the waste liquid produced in the production of the precursor of the positive electrode material of a sodium-ion battery to rectification and two-stage absorption treatment in sequence to recover the volatile components, and at the same time obtain the first treated waste liquid;

[0009] (3) Let the first treated waste liquid obtained in step (2) stand for filtration and adsorptive filtration with activated alumina to recover the insoluble suspended pollutants, and obtain the second treated waste liquid;

[0010] (4) Add a precipitating agent to the second treated waste liquid obtained in step (3) for a metathesis reaction, then let it stand and filter to obtain a filtrate and a filter residue, and the filter residue is recycled.

[0011] (5) Evaporate and concentrate, cool and crystallize, filter, wash and dry the filtrate obtained in step (4) in sequence to recover by-products, and complete the resource treatment of the waste liquid from the production of the precursor of the positive electrode material for sodium-ion batteries.

[0012] Technical principle:

[0013] The components to be recovered in the waste liquid from the production of the precursor of the positive electrode material for sodium-ion batteries are mainly SO 4 2- and NH 4 + . In the present invention, the waste liquid from the production of the precursor of the positive electrode material for sodium-ion batteries is first subjected to rectification treatment to convert the ammonia water in the waste liquid into volatile ammonia gas, and the volatile ammonia gas is recovered by combining two-stage absorption treatment; then the particulate matter in the waste liquid is reduced by physical adsorption, and the insoluble suspended pollutants in the waste liquid are recovered by combining multiple filtrations and separations; finally, a suitable precipitating agent is selected to precipitate SO 4 2- in the waste liquid, so as to achieve the purpose of recovering SO 4 2- ; NH 4 + generated during the precipitation process is recovered by crystallization. The method of the present invention reduces the concentrations of polluting anions and cations in the waste liquid, obtains high-value by-products, effectively recovers sulfate radicals in the waste liquid from the production of the precursor of the positive electrode material for sodium-ion batteries, and there is no wastewater discharge at the same time.

[0014] Further, in step (1), the concentration of SO 4 2- in the waste liquid from the production of the precursor of the positive electrode material for sodium-ion batteries is 11.8 - 12.6 g / L, and the concentration of NH 4 + is 7.9 - 8.7 g / L.

[0015] Further, in step (2), the top temperature of the rectification is 120 - 150 °C, and the bottom temperature is 100 - 130 °C.

[0016] Further, in step (2), the temperature of the two-stage absorption treatment is ≤ 50 °C; the absorbent used for the two-stage absorption treatment is cold water.

[0017] Further, in step (3), the temperature of the standing filtration is 40 - 80 °C, and the time is 8 - 12 h.

[0018] Further, in step (3), the adsorption temperature of the activated alumina adsorption is 30 - 60°C, and the adsorption time is 4 - 8 h.

[0019] Further, in step (4), the precipitating agent is a water-soluble barium salt; the water-soluble barium salt is selected from one or more of barium chloride, barium hydroxide, and barium nitrate.

[0020] Further, in step (4), based on Ba 2+ calculated, the molar ratio of the precipitating agent to the second treated waste liquid based on SO 4 2- calculated is 1:1.05.

[0021] Further, in step (4), the temperature of the metathesis reaction is 20 - 40°C.

[0022] Further, in step (5), the mother liquors generated from evaporation and concentration, cooling and crystallization, filtration, and washing are all returned to the evaporation and concentration process.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] (1) The present invention follows the "whole-process treatment" to treat the end-of-pipe waste liquid, comprehensively combines physical and chemical methods during the treatment process to realize the resource utilization of the waste liquid. After treatment, it meets the national Class IV groundwater quality standard and meets the requirements of green chemistry. At the same time, by-products such as barium sulfate and ammonium chloride in the present invention can achieve considerable economic benefits and reduce the treatment cost. The treatment process of the present invention saves the treatment cost, reduces the pollution risk brought by the experimental process, provides ideas for the treatment method of chemical process waste liquid, lays a foundation for new chemical production, and further promotes the development of green chemistry.

[0025] (2) The treatment process steps of the present invention are safe and simple, the treatment effect is obvious, and no complex equipment is required. The treatment process of the present invention uses rectification, two-stage adsorption, physical adsorption, and multiple filtrations to pre-treat the waste liquid, reducing the material interference for subsequent chemical precipitation. Then, the main polluting ions are removed by the precipitating agent. The multi-level treatment process makes the treatment effect of the waste liquid better.

[0026] (3) The treatment process of the present invention reduces the waste liquid treatment cost, and at the same time, the by-products can also achieve certain economic benefits.

[0027] (4) The treatment process of the present invention provides a new idea for waste liquid treatment and lays a foundation for realizing the green preparation of the precursor of the battery cathode material. Description of the Drawings

[0028] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 It is the process flow diagram of Embodiments 1-4 of the present invention. Detailed implementation manners

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0032] The embodiment of the present invention provides a resource treatment process for the production waste liquid of the sodium-ion battery cathode material precursor, including the following steps:

[0033] (1) Detect the composition of the production waste liquid of the sodium-ion battery cathode material precursor;

[0034] (2) Subject the production waste liquid of the sodium-ion battery cathode material precursor to rectification and two-stage absorption treatment in sequence to recover the volatile components, and at the same time obtain the first treated waste liquid;

[0035] (3) Let the first treated waste liquid obtained in step (2) stand for filtration and adsorb and filter with activated alumina to recover the insoluble suspended pollutants, and obtain the second treated waste liquid;

[0036] (4) Add a precipitant to the second treated waste liquid obtained in step (3) for a metathesis reaction, then let it stand for filtration to obtain a filtrate and a filter residue, and the filter residue is recycled;

[0037] (5) Subject the filtrate obtained in step (4) to evaporation concentration, cooling crystallization, filtration, washing, and drying in sequence to recover the by-products, and complete the resource treatment of the production waste liquid of the sodium-ion battery cathode material precursor.

[0038] In a preferred embodiment, in step (1), the concentration of SO 4 2- in the production waste liquid of the sodium-ion battery cathode material precursor is 11.8 - 12.6 g / L, and the concentration of NH 4 + is 7.9 - 8.7 g / L.

[0039] In a preferred embodiment, in step (1), the waste liquid from the production of the sodium-ion battery cathode material precursor is the waste liquid from the production of the nickel-iron-manganese precursor; the waste liquid from the production of the nickel-iron-manganese precursor mainly contains ammonium sulfate, MnSO 4 , FeSO 4 , NiSO 4 and trace amounts of ammonia water and other pollutants.

[0040] In a preferred embodiment, in step (2), the top temperature of the rectification is 120 - 150 °C, more preferably 125 - 150 °C; the bottom temperature of the rectification is 100 - 130 °C, more preferably 110 - 120 °C. In the present invention, through rectification, the low-boiling component ammonia water in the waste liquid from the production of the sodium-ion battery cathode material precursor is converted into ammonia gas, achieving the purpose of removing ammonia water pollutants from the waste liquid.

[0041] In a preferred embodiment, in step (2), the temperature of the two-stage absorption treatment is ≤ 50 °C, more preferably 30 - 45 °C; the absorbent used in the two-stage absorption treatment is cold water. In the present invention, through the two-stage absorption treatment, the ammonia gas generated in the rectification process is absorbed, achieving the purpose of recovering ammonia water in the waste liquid, and the recovered ammonia water can also achieve certain economic benefits.

[0042] In a preferred embodiment, in step (3), the temperature of the static filtration is 40 - 80 °C, and the time is 8 - 12 h. In the present invention, through static filtration, solid particle pollutants in the waste liquid from the production of the sodium-ion battery cathode material precursor are removed.

[0043] In a preferred embodiment, in step (3), the adsorption temperature of the activated alumina adsorption is 30 - 60 °C, and the adsorption time is 4 - 8 h. In the present invention, by using activated alumina for adsorption filtration, insoluble suspended pollutants in the waste liquid from the production of the sodium-ion battery cathode material precursor are removed, reducing the material interference for subsequent chemical precipitation.

[0044] In a preferred embodiment, in step (4), the precipitating agent is a water-soluble barium salt; the water-soluble barium salt includes one or more of barium chloride, barium hydroxide, and barium nitrate, more preferably barium chloride, and the barium chloride is added in the form of a barium chloride solution, and the mass concentration of the barium chloride solution is 25%. In the present invention, by adding a precipitating agent for a metathesis reaction, the main pollutant ion SO 4 2- in the waste liquid from the production of the sodium-ion battery cathode material precursor is converted into a precipitate, and then barium sulfate is recovered by filtration, reducing the concentration of polluting anions in the waste liquid.

[0045] In a preferred embodiment, in step (4), the precipitating agent based on Ba 2+ and SO4 2- The molar ratio of the second treated waste liquid formulated is 1:1.05.

[0046] In a preferred embodiment, in step (4), the temperature of the double decomposition reaction is 20 - 40 °C.

[0047] In a preferred embodiment, in step (5), the temperature of the evaporation and concentration is 60 - 100 °C. The present invention recovers NH in the filtrate after the double decomposition reaction through evaporation and concentration, cooling crystallization, filtration, washing, and drying. 4 + Finally, the ion concentration in the effluent of the treated waste liquid stably reaches the limit requirements of Class IV of the "Groundwater Quality Standard" (GB / T 14848 - 2017).

[0048] In a preferred embodiment, in step (5), the mother liquors generated from evaporation and concentration, cooling crystallization, filtration, and washing are all returned to the evaporation and concentration process. The present invention returns the mother liquors generated from evaporation and concentration, cooling crystallization, filtration, and washing to the evaporation and concentration process, realizing the recycling of the mother liquors, enabling zero wastewater discharge, and making the production process more environmentally friendly.

[0049] Unless otherwise specified, the raw materials in the embodiments of the present invention are all obtained through commercial channels.

[0050] Example 1

[0051] A resource treatment process for the waste liquid in the production of the precursor of the positive electrode material of a sodium-ion battery. The process flow is shown in Figure 1 and the specific steps are as follows:

[0052] (1) Detect the composition of the waste liquid in the production of the nickel-iron-manganese precursor. It is measured that the concentration of SO in the waste liquid in the production of the nickel-iron-manganese precursor is 12.5 g / L, and the concentration of NH is 8.7 g / L. The waste liquid in the production of the nickel-iron-manganese precursor is passed through a rectification column with a top temperature of 120 °C and a bottom temperature of 100 °C to remove the low-boiling component ammonia gas, obtaining the first treated waste liquid; the obtained ammonia gas enters a two-stage absorption column with a temperature of 30 °C and filled with cold water, and after two-stage absorption treatment, ammonia water is obtained; 4 2- 4 +

[0053] (2) Let the first treated waste liquid obtained in step (1) stand for 8 h at 50 °C, filter, add activated alumina to the filtered filtrate for adsorption at 40 °C, with an adsorption time of 6 h, and filter to recover the insoluble suspended pollutants, obtaining the second treated waste liquid;

[0054] (3) Add a barium chloride solution with a mass concentration of 25% to the second treated waste liquid obtained in step (2), with Ba 2+The molar ratio of the barium chloride solution prepared and the second treated waste liquid calculated as SO 4 2- is 1:1.05. The double decomposition reaction is carried out at 20 °C. After the double decomposition reaction is completed, it is allowed to stand and filtered to obtain a filtrate and barium sulfate precipitate, and the barium sulfate precipitate is recycled;

[0055] (4) The filtrate obtained in step (3) is successively subjected to evaporation concentration, cooling crystallization, filtration, washing and drying to obtain solid NH 4 Cl. The mother liquor generated by evaporation concentration, cooling crystallization, filtration and washing is returned to the evaporation concentration process; wherein, the temperature of evaporation concentration is 80 °C.

[0056] Example 2

[0057] A resource treatment process for the waste liquid in the production of the precursor of the positive electrode material of a sodium ion battery. The process flow is shown in Figure 1 , and the specific steps are as follows:

[0058] (1) Detect the composition of the waste liquid in the production of the nickel-iron-manganese precursor. It is measured that the concentration of SO 4 2- in the waste liquid in the production of the nickel-iron-manganese precursor is 12.1 g / L, and the concentration of NH 4 + is 8.2 g / L. The waste liquid in the production of the nickel-iron-manganese precursor is passed through a rectification column with a top temperature of 130 °C and a bottom temperature of 110 °C to remove the low-boiling component ammonia gas to obtain the first treated waste liquid; the obtained ammonia gas enters a two-stage absorption column with a temperature of 35 °C and filled with cold water, and ammonia water is obtained after two-stage absorption treatment;

[0059] (2) The first treated waste liquid obtained in step (1) is allowed to stand for 9 h at 40 °C and filtered. Activated alumina is added to the filtrate obtained by filtration and adsorbed at 30 °C for 8 h. The insoluble suspended pollutants are filtered and recovered to obtain the second treated waste liquid;

[0060] (3) Add a barium chloride solution with a mass concentration of 25% to the second treated waste liquid obtained in step (2). The molar ratio of the barium chloride solution calculated as Ba 2+ and the second treated waste liquid calculated as SO 4 2- is 1:1.05. The double decomposition reaction is carried out at 25 °C. After the double decomposition reaction is completed, it is allowed to stand and filtered to obtain a filtrate and barium sulfate precipitate, and the barium sulfate precipitate is recycled;

[0061] (4) The filtrate obtained in step (3) is successively subjected to evaporation concentration, cooling crystallization, filtration, washing and drying to obtain solid NH 4 Cl. The mother liquor generated by evaporation concentration, cooling crystallization, filtration and washing is returned to the evaporation concentration process; wherein, the temperature of evaporation concentration is 80 °C.

[0062] Example 3

[0063] A resource treatment process for the waste liquid produced in the production of the precursor of the cathode material for sodium-ion batteries. The process flow is shown in Figure 1 , and the specific steps are as follows:

[0064] (1) Detect the composition of the waste liquid produced in the production of nickel-iron-manganese precursor. It is measured that the concentration of SO 4 2- in the waste liquid produced in the production of nickel-iron-manganese precursor is 12.6 g / L, and the concentration of NH 4 + is 7.9 g / L. Pass the waste liquid produced in the production of nickel-iron-manganese precursor through a distillation column with a top temperature of 125 °C and a bottom temperature of 120 °C to remove the low-boiling component ammonia gas, and obtain the first treated waste liquid; the obtained ammonia gas enters a two-stage absorption column with a temperature of 40 °C and filled with cold water, and ammonia water is obtained after two-stage absorption treatment;

[0065] (2) Let the first treated waste liquid obtained in step (1) stand for 10 h at 60 °C, filter, add activated alumina to the filtered filtrate for adsorption at 50 °C, the adsorption time is 7 h, filter and recover the insoluble suspended pollutants, and obtain the second treated waste liquid;

[0066] (3) Add a barium chloride solution with a mass concentration of 25% to the second treated waste liquid obtained in step (2). The molar ratio of the barium chloride solution calculated by Ba 2+ and the second treated waste liquid calculated by SO 4 2- is 1:1.05. Carry out a metathesis reaction at 30 °C. After the metathesis reaction ends, let it stand and filter to obtain a filtrate and barium sulfate precipitate, and the barium sulfate precipitate is recycled;

[0067] (4) Evaporate, concentrate, cool and crystallize, filter, wash and dry the filtrate obtained in step (3) in sequence to obtain solid NH 4 Cl. The mother liquor generated during evaporation, concentration, cooling crystallization, filtration and washing is returned to the evaporation and concentration process; among them, the temperature of evaporation and concentration is 80 °C.

[0068] Example 4

[0069] A resource treatment process for the waste liquid produced in the production of the precursor of the cathode material for sodium-ion batteries. The process flow is shown in Figure 1 , and the specific steps are as follows:

[0070] (1) Detect the composition of the waste liquid produced in the production of nickel-iron-manganese precursor. It is measured that the concentration of SO 4 2- in the waste liquid produced in the production of nickel-iron-manganese precursor is 11.8 g / L, and the concentration of NH 4 +The concentration is 8.5 g / L. The nickel-iron-manganese precursor production waste liquid is passed through a distillation column with a top temperature of 150 °C and a bottom temperature of 130 °C to remove the low-boiling component ammonia, obtaining the first treated waste liquid; the obtained ammonia enters a two-stage absorption column with a temperature of 45 °C and filled with cold water, and ammonia water is obtained after two-stage absorption treatment.

[0071] (2) The first treated waste liquid obtained in step (1) is left standing for 12 h at 80 °C, filtered, activated alumina is added to the filtrate obtained by filtration, and adsorption is carried out at 60 °C for 8 h. The insoluble suspended pollutants are filtered and recovered to obtain the second treated waste liquid.

[0072] (3) A barium chloride solution with a mass concentration of 25% is added to the second treated waste liquid obtained in step (2). The molar ratio of the barium chloride solution calculated as Ba 2+ and the second treated waste liquid calculated as SO 4 2- is 1:1.05. A double decomposition reaction is carried out at 40 °C. After the double decomposition reaction ends, it is left standing and filtered to obtain a filtrate and barium sulfate precipitate. The barium sulfate precipitate is recycled.

[0073] (4) The filtrate obtained in step (3) is successively subjected to evaporation concentration, cooling crystallization, filtration, washing and drying to obtain solid NH 4 Cl. The mother liquor generated by evaporation concentration, cooling crystallization, filtration and washing is returned to the evaporation concentration process; among them, the temperature of evaporation concentration is 80 °C.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that the order of steps (2) and (3) is reversed, and the specific steps are as follows:

[0076] (1) The composition of the nickel-iron-manganese precursor production waste liquid is detected. It is measured that the SO 4 2- concentration in the nickel-iron-manganese precursor production waste liquid is 12.5 g / L and the NH 4 + concentration is 8.7 g / L. The nickel-iron-manganese precursor production waste liquid is passed through a distillation column with a top temperature of 120 °C and a bottom temperature of 100 °C to remove the low-boiling component ammonia, obtaining the first treated waste liquid; the obtained ammonia enters a two-stage absorption column with a temperature of 30 °C and filled with cold water, and ammonia water is obtained after two-stage absorption treatment.

[0077] (2) A barium chloride solution with a mass concentration of 25% is added to the first treated waste liquid obtained in step (1). The barium chloride solution calculated as Ba 2+ and the SO 4 2-The molar ratio of the first treated waste liquid is 1:1.05, and the double decomposition reaction is carried out at 20 °C. After the double decomposition reaction, it is allowed to stand and filtered to obtain a filtrate and barium sulfate precipitate, and the barium sulfate precipitate is recycled.

[0078] (3) The filtrate obtained in step (2) is allowed to stand at 50 °C for 8 h, filtered, and activated alumina is added to the filtrate obtained by filtration for adsorption at 40 °C for 6 h. The insoluble suspended pollutants are filtered and recovered to obtain the second treated waste liquid.

[0079] (4) The second treated waste liquid obtained in step (3) is successively subjected to evaporation concentration, cooling crystallization, filtration, washing and drying to obtain solid NH 4 Cl. The mother liquor generated from evaporation concentration, cooling crystallization, filtration and washing is returned to the evaporation concentration process; among them, the temperature of evaporation concentration is 80 °C.

[0080] Comparative Example 2

[0081] The difference from Example 1 is that rectification and two-stage absorption treatment are not carried out, and the specific steps are as follows:

[0082] (1) Detect the composition of the nickel-iron-manganese precursor production waste liquid. It is measured that the concentration of SO 4 2- in the nickel-iron-manganese precursor production waste liquid is 12.5 g / L, and the concentration of NH 4 + is 8.7 g / L. The nickel-iron-manganese precursor production waste liquid is allowed to stand at 50 °C for 8 h, filtered, and activated alumina is added to the filtrate obtained by filtration for adsorption at 40 °C for 6 h. The insoluble suspended pollutants are filtered and recovered to obtain the first treated waste liquid.

[0083] (2) Add a barium chloride solution with a mass concentration of 25% to the first treated waste liquid obtained in step (1). The molar ratio of the barium chloride solution based on Ba 2+ and the first treated waste liquid based on SO 4 2- is 1:1.05, and the double decomposition reaction is carried out at 20 °C. After the double decomposition reaction, it is allowed to stand and filtered to obtain a filtrate and barium sulfate precipitate, and the barium sulfate precipitate is recycled.

[0084] (3) The filtrate obtained in step (2) is successively subjected to evaporation concentration, cooling crystallization, filtration, washing and drying to obtain solid NH 4 Cl. The mother liquor generated from evaporation concentration, cooling crystallization, filtration and washing is returned to the evaporation concentration process; among them, the temperature of evaporation concentration is 80 °C.

[0085] Comparative Example 3

[0086] The difference from Example 1 is that step (2) is omitted, and the specific steps are as follows:

[0087] (1) Detect the composition of the waste liquid from the production of nickel-iron-manganese precursor. It is measured that the concentration of SO 4 2- in the waste liquid from the production of nickel-iron-manganese precursor is 12.5 g / L, and the concentration of NH 4 + is 8.7 g / L. The waste liquid from the production of nickel-iron-manganese precursor is passed through a rectifying column with a top temperature of 120 °C and a bottom temperature of 100 °C to remove the low-boiling component ammonia gas, and a first treated waste liquid is obtained; the obtained ammonia gas enters a two-stage absorption column with a temperature of 30 °C and filled with cold water, and ammonia water is obtained after two-stage absorption treatment;

[0088] (2) Add a barium chloride solution with a mass concentration of 25% to the first treated waste liquid obtained in step (1). The molar ratio of the barium chloride solution calculated based on Ba 2+ to the first treated waste liquid calculated based on SO 4 2- is 1:1.05. A double decomposition reaction is carried out at 20 °C. After the double decomposition reaction ends, it is allowed to stand and filtered to obtain a filtrate and barium sulfate precipitate, and the barium sulfate precipitate is recycled;

[0089] (3) The filtrate obtained in step (2) is successively subjected to evaporation concentration, cooling crystallization, filtration, washing and drying to obtain solid NH 4 Cl. The mother liquor generated during evaporation concentration, cooling crystallization, filtration and washing is returned to the evaporation concentration process; among them, the temperature of evaporation concentration is 80 °C.

[0090] The SO 4 2- and NH 4 + ion concentrations in the waste liquid (the filtrate before evaporation concentration) after the treatment of Examples 1-4 and Comparative Examples 1-3 are detected by an ion chromatograph (IC), and the ammonia molecule recovery rate and sulfate removal rate are calculated. The results are shown in Table 1; the production of BaSO 4 and the recovery amount of NH 4 Cl in Examples 1-4 and Comparative Examples 1-3 are counted, and the purity of BaSO 4 is detected. The results are shown in Table 1; the crystallization efficiency after the mother liquor (referring to the mother liquor obtained after cooling crystallization and filtration to recover ammonium chloride) in Examples 1-4 and Comparative Examples 1-3 is reused 3 times is counted, and the results are shown in Table 1.

[0091] Table 1

[0092]

[0093] As can be seen from Table 1, for the resource treatment process of the waste liquid produced in the production of the cathode material precursor of the sodium-ion battery provided by the present invention, the ammonia molecule recovery rate can reach 90.8 - 92.3%, the sulfate removal rate can reach 98.8 - 99.5%, the yield of BaSO 4 is 25.87 - 26.64 kg / m 3 , the purity of BaSO 4 is 98.8 - 99.7%, the recovery amount of NH 4 Cl is 11.7 - 12.3 kg / m 3 , and the crystallization efficiency after the mother liquor is recycled three times is 87 - 91%. For Comparative Examples 1 - 3, the order of steps (2) and (3) was respectively swapped, the rectification and two-stage adsorption treatment were omitted, and step (2) was omitted, and both the ammonia molecule recovery rate and the sulfate removal rate decreased.

[0094] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries, characterized in that: The following steps are involved: (1) Detect the composition of the wastewater produced by the production of sodium ion battery cathode material precursors; (2) subjecting the sodium ion battery positive electrode material precursor production waste liquid to distillation and two-stage absorption treatment in sequence to recover volatile components, thereby obtaining a first treated waste liquid; (3) subjecting the first treated waste liquid obtained in step (2) to static filtration and activated alumina adsorption filtration to recover insoluble suspended pollutants, thereby obtaining a second treated waste liquid; (4) adding a precipitant to the second treated waste liquid obtained in step (3) to carry out a double decomposition reaction, then standing and filtering to obtain a filtrate and a filter residue, and recycling the filter residue; (5) The filtrate obtained in step (4) is sequentially evaporated and concentrated, cooled and crystallized, filtered, washed and dried to recover the by-products, thereby completing the resource treatment of the waste liquid produced by the production of the positive electrode material precursor of the sodium ion battery.

2. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (1), SO4 2- The concentration is 11.8-12.6g / L, NH4 + The concentration is 7.9-8.7g / L.

3. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (2), the top temperature of the distillation tower is 120-150°C, and the bottom temperature of the tower is 100-130°C.

4. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (2), the temperature of the two-stage absorption treatment is ≤50°C; and the absorbent used in the two-stage absorption treatment is cold water.

5. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (3), the temperature of the static filtration is 40-80°C and the time is 8-12 hours.

6. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (3), the adsorption temperature of the activated alumina is 30-60°C, and the adsorption time is 4-8h.

7. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (4), the precipitant is a water-soluble barium salt; the water-soluble barium salt is selected from one or more of barium chloride, barium hydroxide and barium nitrate.

8. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 7, characterized in that: In step (4), Ba 2+ The precipitant and SO4 2- The molar ratio of the second treated waste liquid is 1:1.

05.

9. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (4), the temperature of the metathesis reaction is 20-40°C.

10. The process for recycling waste liquid produced from the production of positive electrode material precursors for sodium ion batteries according to claim 1, characterized in that: In step (5), the mother liquor produced by evaporation concentration, cooling crystallization, filtration and washing is returned to the evaporation concentration step.

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