Process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater

Abstract

A process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater, comprising the following steps: S1: Mixing a carbon black powder with an ammonium salt solution, heating for a hydrothermal reaction, and then filtering; washing a resulting filter residue with acid to obtain ammonium salt-modified carbon black; mixing a mixed nickel-cobalt-manganese salt and a sodium salt to obtain a mixture; mixing the mixture with an organic acid solution, evaporating to remove water, and conducting a heating reaction in an inert atmosphere; washing a resulting product after the heating reaction with acid to obtain a mixed nickel-cobalt-manganese sodium salt; S2: Mixing the mixed nickel-cobalt-manganese sodium salt, the ammonium salt-modified carbon black, and a binder, and compacting, drying, and heating a resulting mixture to obtain a multimetal carbon-based adsorbent; wherein, in step S1, the carbon black powder is obtained by acid oxidation leaching of battery powder obtained from a lithium battery; In step S1, the ammonium salt solution is at least one selected from ammonium sulfate, ammonium bisulfate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium phosphate, and ammonium dihydrogen phosphate solutions; wherein a solid-liquid ratio of the carbon black powder to the ammonium salt solution is 10 g / l to 500 g / l, and a mass concentration of the ammonium salt solution is 0.1% to 30%; in step S1, the nickel-cobalt-manganese mixed salt is produced by battery recycling; and the mass ratio of the sodium salt to the nickel-cobalt-manganese mixed salt is 1-10: 0.1-30; and In stage S2, the mass ratio of the nickel-cobalt-manganese-sodium mixed salt to the ammonium salt-modified carbon black to the binder is 10-50: 30-70: 0.1-8.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of wastewater treatment, in particular to a process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater and the use of a ternary precursor of the wastewater adsorbent in the treatment of ternary precursor wastewaters. BACKGROUND

[0002] Currently, ternary cathode material is obtained through the synthesis by sintering lithium salt and ternary precursor. The synthesis process of the ternary precursor includes the following two types: 1. Lithium-ion battery waste / electrode plates are disassembled and recycled to obtain battery powder, which is calcined, leached by acid oxidation, extracted, and purified to obtain a mixed nickel-cobalt-manganese salt, to which alkali and ammonia are added to obtain ternary precursor products. 2. Various minerals undergo acid leaching, precipitation and impurity removal, extraction, and purification to obtain a nickel, cobalt, and manganese salt, respectively, which is used in combination with alkali and ammonia in the synthesis to obtain ternary precursor products.Both synthesis processes of the above-mentioned synthetic ternary precursors inevitably require the use of acids, especially sulfuric acid as a leaching agent, alkali as a precipitating and regulating agent, ammonia as a complexing agent, and organic extractants to extract nickel, cobalt, and manganese metal ions. To prevent ammonium salts, sulfates, and organic extractants from remaining in the nickel-cobalt-manganese salt solution, resulting in a higher content of ammonium salts, sulfates, and organic extractants in the ternary precursor that exceeds the permissible norm for the product, multiple pressure filtration and washing are often used to remove sodium ions. Therefore, more pure water is required to repeatedly wash out ammonium salts, sulfates, organic extractants, and other soluble impurities.Water consumption will increase, wastewater generation will increase, and wastewater treatment costs will rise. On the other hand, the concentration of ammonium salts, sulfates, and organic extractants in the wastewater will decrease with the number of washing cycles, making treatment difficult and deep removal of ammonium salts, sulfates, and organic extractants impossible.

[0003] WO 2019 / 054214 A1 discloses a liquid-phase heavy metal treatment agent comprising an activated carbon on which a compound containing a first transition metal element is applied. The invention also discloses a method for producing the heavy metal treatment agent. The method comprises a process in which a metal compound, a polar solvent, and activated carbon are brought into contact with each other, wherein the metal in the metal compound used in the contact process is the first transition metal, and the Snyder polarity parameter of the polar solvent used in the contact process is 3.5 or higher.

[0004] CN 110813235 A discloses a nickel ion adsorbent and a method for its production. The production method comprises the following steps: drying green walnut shells to obtain dried walnut shells; crushing and mixing the dried walnut shells and ammonium oxalate to obtain a mixed sample; carbonizing and pyrolyzing the mixed sample to obtain a starting adsorbent; sequentially immersing and reactivating the starting adsorbent to obtain an activated adsorbent; and modifying the activated adsorbent with a potassium permanganate solution to obtain the nickel ion adsorbent.

[0005] CN 107376862 A discloses a method for producing an adsorbent from waste and scrap zinc-manganese batteries and biomass. An anode material and hydrochloric acid are weighed according to the molar concentration of ZnCl2, and a quantity of deionized water and a mass of a mixed raw material consisting of a cathode material and pulverized biomass are determined according to the weighed anode material and hydrochloric acid. The mixed raw material mass is activated in two steps under specific conditions. After the two-step activation, the products are carbonized. The carbonized products are repeatedly washed with distilled water until a neutral pH is reached. Subsequently, the materials are dried in an oven, and the dried samples are thoroughly ground to produce the waste and scrap zinc-manganese battery biomass adsorbent. SUMMARY

[0006] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this reason, the present invention proposes a process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater and the use of a ternary precursor of the wastewater adsorbent in the treatment of ternary precursor wastewater. The first aim is to produce a wastewater adsorbent, and the second aim is to provide a wastewater treatment process that uses the aforementioned wastewater treatment agent for the deep removal of ammonium salts, sulfates, and organic extractants.

[0007] According to one aspect of the present invention, a process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater is proposed, comprising the following steps: S1: Mixing a carbon black powder with an ammonium salt solution, heating for a hydrothermal reaction, and then filtering; washing a resulting filter residue with acid to obtain ammonium salt-modified carbon black; mixing a mixed nickel-cobalt-manganese salt and a sodium salt to obtain a mixture; mixing the mixture with an organic acid solution, evaporating to remove water, and conducting a heating reaction in an inert atmosphere; washing a resulting product after the heating reaction with acid to obtain a mixed nickel-cobalt-manganese sodium salt; S2: Mixing the mixed nickel-cobalt-manganese sodium salt, the ammonium salt-modified carbon black and a binder, and compacting, drying and heating a resulting mixture to obtain a multimetal carbon-based adsorbent;wherein, in step S1, the carbon black powder is obtained by acid oxidation leaching of battery powder obtained from a lithium battery; In step S1, the ammonium salt solution is at least one selected from ammonium sulfate, ammonium bisulfate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium phosphate, and ammonium dihydrogen phosphate solutions; wherein a solid-liquid ratio of the carbon black powder to the ammonium salt solution is 10 g / l to 500 g / l, and a mass concentration of the ammonium salt solution is 0.1% to 30%; in step S1, the nickel-cobalt-manganese mixed salt is produced by battery recycling; and the mass ratio of the sodium salt to the nickel-cobalt-manganese mixed salt (1-10): (0.1-30); and in stage S2, the mass ratio of the nickel-cobalt-manganese-sodium mixed salt to the ammonium salt-modified carbon black to the binder is (10-50): (30-70): (0.1-8).

[0008] The heating in step S2 is carried out under a nitrogen gas atmosphere.

[0009] After compaction, a specific shape is obtained, such as a leaf shape, a block shape, a long rod shape, a spherical shape and an irregular polygon shape.

[0010] In some preferred embodiments of the present invention, in step S1, the average particle size of the carbon black powder is less than 0.1 mm.

[0011] In some preferred embodiments of the present invention, the ammonium salt solution in step S1 is ammonium sulfate and / or ammonium bisulfate solution.

[0012] In some preferred embodiments of the present invention, the solid-liquid ratio of the carbon black powder to the ammonium salt solution is 50 g / l to 200 g / l.

[0013] In some preferred embodiments of the present invention, the mass concentration of the ammonium salt solution is 1% to 10%.

[0014] In some preferred embodiments of the present invention, in step S1, the temperature of the hydrothermal reaction is 100°C to 400°C; and the hydrothermal reaction lasts 1 h to 10 h.

[0015] In some preferred embodiments of the present invention, the sodium salt in step S1 is at least one selected from: sodium acetate, sodium hydroxide, sodium sulfate, sodium phosphate, sodium chloride, sodium nitrate, sodium oxalate, sodium citrate, sodium manganate and sodium carbonate.

[0016] In some preferred embodiments of the present invention, in step S1 the average particle size of the mixture is less than 100 µm.

[0017] In some preferred embodiments of the present invention, the acid in step S1 is at least one selected from sulfuric acid, nitric acid, phosphoric acid, and hydrochloric acid; more preferably, the concentration of the acid is 0.1 mol / L to 5 mol / L. In some preferred embodiments of the present invention, in step S1, the organic acid solution is one or more solutions of acids selected from oxalic acid, citric acid, formic acid, and acetic acid; the solid-liquid ratio of the mixture to the organic acid solution is preferably 10 g : 50-200 ml, and the mass concentration of the organic acid solution is 1% to 40%.

[0018] In some preferred embodiments of the present invention, the temperature of the heating reaction in step S1 is 300 °C to 1100 °C; and the heating reaction lasts 2 h to 24 h.

[0019] In some preferred embodiments of the present invention, the binder in step S2 is at least one selected from calcium silicate, calcium alginate, clay silicate and sodium aluminosilicate.

[0020] In some preferred embodiments of the present invention, in step S2, the resulting mixture is heated to 300°C to 800°C, and more preferably, the resulting mixture is heated for 2 h to 24 h.

[0021] In some preferred embodiments of the present invention, in step S2, the density after compaction of the resulting mixture is more than 1.8 g / cm 3 .

[0022] The present invention also provides the use of the wastewater adsorbent prepared by the above process in the treatment of ternary precursor wastewaters.

[0023] In some embodiments of the present invention, the method for treating ternary precursor wastewater comprises settling, filtering, and strongly oxidizing the ternary precursor wastewater to obtain primary treated wastewater, adding the wastewater adsorbent to the primary treated wastewater for adsorption treatment, soaking the wastewater adsorbent after treatment in an acid for desorption, after 2-6 times of adsorption-desorption treatment, sending the treated wastewater for secondary treatment, and reusing the wastewater adsorbent for adsorption treatment. It should be noted that the ternary precursor wastewater is the wastewater produced by acid leaching, precipitation and impurity removal, extraction and separation, alkali addition, ammonia addition, and aging in the ternary precursor production process.

[0024] In some preferred embodiments of the present invention, the solid-liquid ratio of the wastewater adsorbent to the primary treated wastewater is 0.5-20 kg : 30-200 l.

[0025] In some preferred embodiments of the present invention, the acid used for soaking and desorption is at least one selected from sulfuric acid, nitric acid, phosphoric acid and hydrochloric acid, and more preferably its concentration is 0.01 mol / L to 3 mol / L.

[0026] According to a preferred embodiment of the present invention, it has at least the following advantageous effects.

[0027] 1. The wastewater adsorbent of the present invention has high stability and diverse adsorption properties. After the carbon black powder in the wastewater adsorbent is modified with hydrothermal ammonium salt, the polarity and acid-base properties of the carbon black powder are significantly changed, and the adsorption performance for the ammonium radical is improved.In the nickel-cobalt-manganese salt mixture, manganese salt is the main material of the adsorbent polymetallic salt. The addition of cobalt salt / nickel salt to strengthen the stability of the adsorbent, the use of carbon black powder as the base material of the adsorbent, and the heating to synthesize the multi-metal carbon-based adsorbent can further enhance the inherent excellent properties of the porous carbon in the carbon black powder, improve its surface properties, promote the interaction between the adsorbent and the ions, and improve the adsorption performance. The multi-metal carbon-based adsorbent prepared in the present invention has a specific adsorption capacity for sodium, ammonium, and sulfate. As a base carbon material, carbon black powder can simultaneously adsorb calcium, iron, manganese, cobalt, and many other ions. It has a wide range of adsorption properties.In addition, the adsorbent can be reused after desorption treatment and has the ability of repeated adsorption.

[0028] 2. With the process of the present invention, production costs are significantly reduced. On the one hand, the raw material source of the multi-metal carbon-based adsorbent synthesized by the invention can be the product recovered from the waste battery, where the carbon black powder can come from the anode material of the waste battery, and the nickel-cobalt-manganese-sodium mixed salt can come from the cathode material of the waste battery. Therefore, the main materials of the adsorbent are obtained through the secondary recycling of the waste material. On the other hand, the adsorbent produced by the present invention can be reused. After adsorbing the wastewater from the primary treatment, the adsorbent can be added to an acid for desorption treatment and reused. Therefore, the recycling rate of the material in the present invention is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be described in more detail below in conjunction with the accompanying drawings and embodiments, in which: Fig. 1 is a process flow diagram for Embodiment 1 of the present invention; Fig. 2 is an SEM photograph of the wastewater adsorbent prepared in Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Hereinafter, the concept of the present invention and the achieved technical effects will be described clearly and completely in conjunction with the embodiments in order to fully understand the purpose, features and effects of the present invention. Example 1

[0031] A process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater and a wastewater treatment process based on Fig. refers to, the specific procedure being as follows: (1) Modification of soot residue: The battery powder obtained from the lithium battery was subjected to leaching with acidic oxidants to obtain soot residue. The soot residue was washed, dried, and ground to an average particle size of less than 0.1 mm to obtain soot residue powder. 34 g of soot residue powder was mixed with 200 ml of 3.3% ammonium sulfate solution and stirred to obtain a soot residue slurry. The soot slurry was placed in a closed container for heating and subjected to hydrothermal treatment at 160°C for 3 hours and 3 minutes; it was cooled and filtered. The filter residue was washed with dilute acid and dried to obtain ammonium sulfate-modified soot residue. (2) Preparation of nickel-cobalt-manganese-sodium mixed salt: The nickel-cobalt-manganese mixed salt produced by battery recycling was mixed with sodium sulfate and ground to an average particle size of less than 100 μm to obtain a mixture. The mixture was uniformly mixed with 6.12 wt% oxalic acid solution, subjected to solid-liquid separation, and evaporated to remove water. It was heated at 430 °C for 3 hours and 44 minutes under an inert atmosphere and cooled. The resulting product was pickled with 0.34 mol / L hydrochloric acid, washed, and dried to obtain a nickel-cobalt-manganese sodium mixed salt. wherein the mass ratio of sodium sulfate to the nickel-cobalt-manganese mixed salt is 3:12 and the solid-liquid ratio of the mixture to the oxalic acid solution is 10:50 g / ml. (3) Synthesis of a multimetal carbon-based adsorbent: 15.8 g of nickel-cobalt-manganese-sodium mixed salt, 34 g of ammonium sulfate-modified carbon black residue, and 5 g of silicate clay were mixed and compacted to form a specific flake shape with a compaction density of 2.53 g / cm 3 which was dried, heated at 485 °C in a nitrogen atmosphere for 2 h and 12 min, and cooled to obtain a multimetal carbon-based adsorbent. (4) Wastewater treatment by adsorption using adsorbents: The wastewater generated during the production of the ternary precursor was settled, filtered, and highly oxidized to obtain the primary treated wastewater, and the multimetal carbon-based adsorbent was added for adsorption treatment. After treatment, the adsorbent was soaked in 0.34 mol / L hydrochloric acid for desorption. After five adsorption-desorption treatments, the treated wastewater was sent to the secondary treatment, and the adsorbent was reused for adsorption treatment. where the solid-liquid ratio of adsorbent to wastewater is 1: 13 g / ml. Example 2

[0032] A process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater and a process for wastewater treatment were provided, and the specific process was as follows: (1) Modification of soot residue: The battery powder obtained from the lithium battery was subjected to leaching with acidic oxidants to obtain soot residue. The soot residue was washed, dried, and ground to an average particle size of less than 0.1 mm to obtain soot residue powder. 45 g of soot residue powder was mixed with 280 ml of 3.7% ammonium sulfate solution and stirred to obtain a soot residue slurry. The soot residue slurry was placed in a closed container for heating and subjected to hydrothermal treatment at 185°C for 2 hours and 13 minutes, cooled, and filtered. The filter residue was washed with diluted acid and dried to obtain ammonium sulfate-modified soot residue. (2) Preparation of nickel-cobalt-manganese-sodium mixed salt: The nickel-cobalt-manganese mixed salt obtained by battery recycling was mixed with sodium sulfate and ground to an average particle size of less than 100 μm to obtain a mixture. The mixture was uniformly mixed with 3.41 wt% oxalic acid solution, subjected to solid-liquid separation, evaporated to remove water, heated at 425 °C for 3 hours and 54 minutes under an inert atmosphere, and cooled. The resulting product was pickled with 0.34 mol / L hydrochloric acid, washed, and dried to obtain a nickel-cobalt-manganese-sodium mixed salt. wherein the mass ratio of sodium sulfate to the nickel-cobalt-manganese mixed salt is 5:17 and the solid-liquid ratio of the mixture to the oxalic acid solution is 10:65 g / ml. (3) Synthesis of a multimetal carbon-based adsorbent: 22 g of a mixed nickel-cobalt-manganese sodium salt, 45 g of a carbon black residue modified with ammonium sulfate, and 7 g of silicate clay were mixed and compacted to form a specific flake shape with a compaction density of 2.23 g / cm 3 which was dried, heated at 485 °C in a nitrogen atmosphere for 2 h and 12 min, and cooled to obtain a multimetal carbon-based adsorbent; where the mass ratio of mixed nickel-cobalt-manganese sodium salt to ammonium sulfate modified soot residue to silicate clay was 35: 70: 2.3. (4) Wastewater treatment by adsorption using adsorbents: The wastewater generated during the production of the ternary precursor was settled, filtered, and highly oxidized to obtain the primary treated wastewater, and the multimetal carbon-based adsorbent was added for adsorption treatment. After treatment, the adsorbent was soaked in 0.34 mol / L hydrochloric acid for desorption. After five adsorption-desorption treatments, the treated wastewater was sent to the secondary treatment, and the adsorbent was reused for adsorption treatment. where the solid-liquid ratio of adsorbent to wastewater is 1: 9 kg / l.

[0033] Fig. Figure 2 is an SEM image of the wastewater adsorbent produced in this embodiment. From the figure, it can be seen that the adsorbent has a structure with a rough surface and pores inside. Example 3

[0034] A process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater and a process for wastewater treatment were provided, and the specific process was as follows: (1) Modification of soot residue: The battery powder obtained from the lithium battery was subjected to leaching with acidic oxidants to obtain soot residue. The soot residue was washed, dried, and ground to an average particle size of less than 0.1 mm to obtain soot residue powder. 36 g of soot residue powder was mixed with 240 ml of 4.4% ammonium chloride solution and stirred to obtain a soot residue slurry. The soot slurry was placed in a closed container for heating and subjected to hydrothermal treatment at 160°C for 2 hours and 33 minutes, cooled, and filtered. The filter residue was washed with dilute acid and dried to obtain ammonium chloride-modified soot residue. (2) Preparation of nickel-cobalt-manganese-sodium mixed salt: The nickel-cobalt-manganese mixed salt produced by battery recycling was mixed with sodium sulfate and ground to an average particle size of less than 100 μm to obtain a mixture. The mixture was uniformly mixed with 6.33 wt% oxalic acid solution, subjected to solid-liquid separation, and evaporated to remove water. It was heated at 430 °C for 3 h and 34 min under an inert atmosphere and cooled. The resulting product was pickled with 0.34 mol / L hydrochloric acid, washed, and dried to obtain a nickel-cobalt-manganese-sodium mixed salt. wherein the mass ratio of sodium sulfate to the nickel-cobalt-manganese mixed salt is 4:13 and the solid-liquid ratio of the mixture to the oxalic acid solution is 10:50 g / ml. (3) Synthesis of a multimetal carbon-based adsorbent: 17 g of nickel-cobalt-manganese-sodium mixed salt, 36 g of ammonium chloride-modified carbon black residue, and 5 g of silicate clay were mixed and compacted to form a specific block shape with a compaction density of 2.07 g / cm 3 which was dried, heated at 485 °C in a nitrogen atmosphere for 2 h and 12 min, and cooled to obtain a multimetal carbon-based adsorbent. (4) Wastewater treatment by adsorption using adsorbents: The wastewater generated during the production of the ternary precursor was settled, filtered, and highly oxidized to obtain the primary treated wastewater, and the multimetal carbon-based adsorbent was added for adsorption treatment. After treatment, the adsorbent was soaked in 0.34 mol / L hydrochloric acid for desorption. After five adsorption-desorption treatments, the treated wastewater was sent to the secondary treatment, and the adsorbent was reused for adsorption treatment. where the solid-liquid ratio of adsorbent to wastewater was 1:7 kg / l. Example 4

[0035] A process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater and a process for wastewater treatment were provided, and the specific process was as follows: (1) Modification of soot residue: The battery powder obtained from the lithium battery was subjected to leaching with acidic oxidants to obtain soot residue. The soot residue was washed, dried, and ground to an average particle size of less than 0.1 mm to obtain soot residue powder. 25 g of soot residue powder was mixed with 200 mL of 5.3% ammonium chloride solution and stirred to obtain a soot slurry. The soot slurry was placed in a closed container for heating and subjected to hydrothermal treatment at 160 °C for 3 hours and 8 minutes, cooled, and filtered. The filter residue was washed with dilute acid and dried to obtain ammonium chloride-modified soot residue. (2) Preparation of nickel-cobalt-manganese-sodium mixed salt: The nickel-cobalt-manganese mixed salt obtained by battery recycling was mixed with sodium sulfate and ground to an average particle size of less than 100 μm to obtain a mixture. The mixture was uniformly mixed with 6.12 wt% oxalic acid solution, subjected to solid-liquid separation, and evaporated to remove water. The mixture was heated at 430 °C for 3 h and 17 min under an inert atmosphere and cooled. The resulting product was pickled with 0.34 mol / L hydrochloric acid, washed, and dried to obtain a nickel-cobalt-manganese sodium mixed salt. wherein the mass ratio of sodium sulfate to the nickel-cobalt-manganese mixed salt is 5:15 and the solid-liquid ratio of the mixture to the oxalic acid solution is 10:50 g / ml. (3) Synthesis of a multimetal carbon-based adsorbent: 8 g of nickel-cobalt-manganese-sodium mixed salt, 25 g of ammonium chloride-modified carbon black residue, and 3 g of siliceous clay were mixed and compacted to form a specific block shape with a compaction density of 2.47 g / cm 3 which was dried, heated at 485 °C under a nitrogen atmosphere for 2 h and 12 min, and cooled to obtain a multimetal carbon-based adsorbent. (4) Wastewater treatment by adsorption using adsorbents: The wastewater generated during the production of the ternary precursor was settled, filtered, and highly oxidized to obtain the primary treated wastewater, and the multimetal carbon-based adsorbent was added for adsorption treatment. After treatment, the adsorbent was soaked in 0.34 mol / L hydrochloric acid for desorption. After five adsorption-desorption treatments, the treated wastewater was sent to the secondary treatment, and the adsorbent was reused for adsorption treatment. where the solid-liquid ratio of adsorbent to wastewater is 1: 10 g / l. Comparison example 1

[0036] The difference between this comparative example and working example 1 was that the soot residue was not modified in step (1). Comparison example 2

[0037] The difference between this comparative example and working example 1 was that the nickel-cobalt-manganese sodium salt mixture was not added in step (3). Comparison example 3

[0038] The difference between this Comparative Example and Working Example 3 is that the nickel-cobalt-manganese sodium salt mixture was not added in step (3). Table 1 The impurity content of the wastewater before and after the adsorption treatment of Working Examples 1-4 and Comparative Examples 1-3. element Ni (mg / l) Fe (mg / l) Na (mg / l) Ca (mg / l) Total nitrogen (mg / l) Total phosphorus (mg / l) Example 1 before adsorption 145,7 486 2634 778 3566 387 after adsorption 66,3 132 371 298 768 49 Example 2 before adsorption 173,4 450 2431 763 3323 344 after adsorption 51,8 107 325 268 413 38,4 Example 3 before adsorption 155,3 631 3157 831 3978 396 after adsorption 70,9 78 323 325 743 54,7 Example 4 before adsorption 164,5 539 2568 764 3516 354 after adsorption 54,0 32 344 274 935 73,3 Comparison example 1 before adsorption 147,6 472 2544 770 3480 383 after adsorption 93,5 177 383 356 1156 81,6 Comparison example 2 before adsorption 143,1 482 2643 815 3398 302 after adsorption 111,7 156 554 372 934 77,5 Comparison example 3 before adsorption 153,3 636 3176 863 3824 387 after adsorption 118,6 174 638 396 928 68,3

[0039] Table 1 shows that, compared to Comparative Example 1, the removal of ammonia and nitrogen in the wastewater of Working Examples 1-4 was significantly improved after the ammonium salt modification. On the other hand, compared to Comparative Examples 2 and 3, the removal of nickel and sodium in the wastewater was significantly improved after the addition of the nickel-cobalt-manganese-sodium mixed salt.

Claims

[1] A process for producing a wastewater adsorbent for use in the treatment of ternary precursor wastewater, comprising the following steps: S1: Mixing a carbon black powder with an ammonium salt solution, heating for a hydrothermal reaction, and then filtering; washing a resulting filter residue with acid to obtain ammonium salt-modified carbon black; mixing a mixed nickel-cobalt-manganese salt and a sodium salt to obtain a mixture; mixing the mixture with an organic acid solution, evaporating to remove water, and conducting a heating reaction in an inert atmosphere; washing a resulting product after the heating reaction with acid to obtain a mixed nickel-cobalt-manganese sodium salt; S2: Mixing the mixed nickel-cobalt-manganese sodium salt, the ammonium salt-modified carbon black, and a binder, and compacting, drying, and heating a resulting mixture to obtain a multimetal carbon-based adsorbent; wherein, in step S1, the carbon black powder is obtained by acid oxidation leaching of battery powder obtained from a lithium battery; In step S1, the ammonium salt solution is at least one selected from ammonium sulfate, ammonium bisulfate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium phosphate, and ammonium dihydrogen phosphate solutions; wherein a solid-liquid ratio of the carbon black powder to the ammonium salt solution is 10 g / l to 500 g / l, and a mass concentration of the ammonium salt solution is 0.1% to 30%; in step S1, the nickel-cobalt-manganese mixed salt is produced by battery recycling; and the mass ratio of the sodium salt to the nickel-cobalt-manganese mixed salt is 1-10: 0.1-30; and In stage S2, the mass ratio of the nickel-cobalt-manganese-sodium mixed salt to the ammonium salt-modified carbon black to the binder is 10-50: 30-70: 0.1-8. [2] The manufacturing method according to claim 1, wherein in step S1, the temperature of the hydrothermal reaction is 100 °C to 400 °C; and the hydrothermal reaction lasts for 1 h to 10 h. [3] The manufacturing method according to claim 1, wherein in step S1, the organic acid solution is one or more solutions of acids selected from oxalic acid, citric acid, formic acid, and acetic acid; wherein a solid-liquid ratio of the mixture to the organic acid solution is 10 g: 50-200 ml, and a mass concentration of the organic acid solution is 1% to 40%. [4] The manufacturing method according to claim 1, wherein in step S1, the temperature of the heating reaction is 300 °C to 1100 °C; and the heating reaction lasts 2 h to 24 h. [5] The manufacturing method according to claim 1, wherein in step S2, the binder is at least one selected from calcium silicate, calcium alginate, clay silicate and sodium aluminosilicate. [6] Use of a ternary precursor of the wastewater adsorbent in the treatment of ternary precursor wastewaters, wherein the ternary precursor wastewater adsorbent is produced by the production process according to any one of claims 1 to 5.

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