Method for efficiently and resourcefully preparing high-tap-density sodium electric precursor

Abstract

The invention discloses a method for efficiently and resourcefully preparing a high-tap-density sodium electric precursor, and belongs to the technical field of sodium ion battery materials. According to the method, the ferro-manganese elements in the metallurgical waste residues are recycled, the ferro-manganese mixed salt solution is prepared by combining the ferro-manganese elements with the nickel salt, and then the ferro-manganese-based hydroxide precursor material which is good in sphericity degree, high in tap density and uniform in element distribution is prepared by adopting a multi-stage crystal growth technology. When the prepared nickel-iron-manganese-based hydroxide precursor is applied to a sodium ion battery, the energy density of the battery can be improved, the cycle life of the battery can be prolonged, meanwhile, part of raw materials for preparing the nickel-iron-manganese-based hydroxide precursor come from waste residues, waste liquid generated by washing is converted into by-products through chemical precipitation, pollution is reduced, and the nickel-iron-manganese-based hydroxide precursor is suitable for industrial production. The resource utilization rate is improved, and the waste is converted into a battery material.

Description

Technical Field

[0001] The invention belongs to the technical field of sodium ion battery materials, and in particular relates to a method for efficiently and resourcefully preparing a sodium battery precursor with a high tap density. Background Art

[0002] As a new type of energy storage material, sodium-ion batteries are rich in resources, have high crustal abundance, and are green and environmentally friendly. At the same time, sodium-ion batteries have higher internal resistance than lithium-ion batteries, generate less instantaneous heat in the case of a short circuit, have lower temperature rise, and have higher thermal runaway temperatures. They have higher safety and are widely used in electric vehicles, smart grids, and other fields.

[0003] However, the impact of process parameters on material properties and waste liquid pollution in the preparation of positive electrode materials for sodium ion batteries have limited their large-scale commercial application. When preparing ternary precursors by the traditional co-precipitation method, due to the large differences in the precipitation coefficients of metal ions, it is easy to cause uneven precipitation and affect material properties. In addition, if the waste liquid generated during the preparation process is not properly handled, it will increase environmental pollution and energy consumption. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a method for preparing a sodium electrode precursor with high tap density in an efficient and resource-saving manner.

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

[0006] The present invention provides a method for efficiently and resourcefully preparing a sodium electrode precursor with a high tap density, comprising the following steps:

[0007] (1) subjecting metallurgical waste slag to two-stage sulfuric acid roasting, separating and extracting iron and manganese elements, and supplementing nickel salt to obtain a nickel-iron-manganese mixed salt solution;

[0008] (2) under a protective atmosphere, adding the nickel-iron-manganese mixed salt solution obtained in step (1) and a precipitant in parallel to a base liquid containing a complexing agent to carry out a coprecipitation reaction, and then aging, washing and drying to obtain a nickel-iron-manganese-based hydroxide precursor;

[0009] (3) chemically precipitating and evaporating the waste liquid generated by washing in step (2) to complete the recycling of the waste liquid.

[0010] The present invention recycles the iron and manganese elements in the metallurgical waste slag, combines with nickel salt to prepare a nickel-iron-manganese mixed salt solution, and then adopts a multi-stage crystal growth technology to prepare a nickel-iron-manganese-based hydroxide precursor material with good sphericity, high tap density and uniform element distribution. At the same time, the present invention realizes the recycling of resources and effective control of pollutants by harmlessly treating the washing waste liquid generated in the preparation process and recovering the by-products.

[0011] Furthermore, in step (1), the contents of each element in the metallurgical waste slag satisfy the following requirements: Fe≥15.6%, Mn≥10.9%, W≤2.5%, Ca≤20.0%, Si≤3.8%, Zn≤0.3%, Sn≤0.7%, Na≤1.2%, S≤1.4%, Al≤0.8%, and Pb≤0.3%.

[0012] Furthermore, in step (1), the two-stage sulfation roasting includes low-temperature roasting and high-temperature roasting; the temperature of the low-temperature roasting is 120-350°C and the time is 20-180 minutes; the temperature of the high-temperature roasting is 500-800°C and the time is 50-200 minutes.

[0013] Furthermore, in step (1), the mass fraction of sulfuric acid used in the two-stage sulfation roasting is 40-50%.

[0014] Furthermore, in step (1), the nickel-iron-manganese mixed salt solution contains nickel salt, divalent iron salt and manganese salt; the molar ratio of the nickel salt, divalent iron salt and manganese salt is x:y:(1-xy), wherein 0.1≤x≤0.5, 0.2≤y≤0.5; and the concentration of the nickel-iron-manganese mixed salt solution is 1.0-3.5 mol / L in terms of metal ion concentration.

[0015] Furthermore, in step (2), the precipitant is a sodium hydroxide solution; and the concentration of the sodium hydroxide solution is 1-6 mol / L.

[0016] Furthermore, in step (2), the base liquid containing the complexing agent consists of oxygen-free water, an antioxidant and a complexing agent; and the complexing agent is ammonia water.

[0017] Further, in step (2), the coprecipitation reaction includes a first stage and a second stage;

[0018] The first stage is the nucleation stage, and the reaction parameters are: the pH value of the reaction system is 10.00-12.30, the concentration of the complexing agent is 0.06-0.50 mol / L, and the nucleation time is 8-12h;

[0019] The second stage is the growth stage, and the reaction parameters are: the pH value of the reaction system is 9.80-11.00, the concentration of the complexing agent is 0.06-0.50 mol / L, and the growth time is 12-20 hours.

[0020] Furthermore, in step (2), the D50 (median particle size) of the nickel-iron-manganese-based hydroxide precursor is 4-10 μm, and the SPAN (particle size distribution width) is 0.5-0.8.

[0021] Furthermore, in step (3), the precipitant used for the chemical precipitation is a barium chloride solution; and the concentration of the barium chloride solution is 1-3 mol / L.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] (1) The method provided by the present invention is simple and easy to implement, the raw material cost is low, the prepared precursor morphology is controllable, the tap density is high, and it is suitable for large-scale production.

[0024] (2) The nickel-iron-manganese-based hydroxide precursor prepared by the present invention, when applied to a sodium ion battery, helps to improve the energy density and cycle life of the battery. At the same time, part of the raw materials for preparing the nickel-iron-manganese-based hydroxide precursor by the present invention come from waste residues, and the waste liquid generated by washing is also converted into by-products through chemical precipitation, thereby reducing pollution, improving resource utilization, and realizing the transformation of waste into battery materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary 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 accompanying drawings:

[0026] Figure 1 This is a process flow chart of Example 1-2 of the present invention;

[0027] Figure 2 This is a SEM image of the high tap density sodium electrode precursor prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The embodiment of the present invention provides a method for efficiently and resourcefully preparing a sodium electrode precursor with a high tap density, comprising the following steps:

[0031] (1) subjecting metallurgical waste slag to two-stage sulfuric acid roasting, separating and extracting iron and manganese elements, and supplementing nickel salt to obtain a nickel-iron-manganese mixed salt solution;

[0032] (2) under a protective atmosphere, adding the nickel-iron-manganese mixed salt solution obtained in step (1) and a precipitant in parallel to a base liquid containing a complexing agent to carry out a coprecipitation reaction, and then aging, washing and drying to obtain a nickel-iron-manganese-based hydroxide precursor;

[0033] (3) chemically precipitating and evaporating the waste liquid generated by washing in step (2) to complete the recycling of the waste liquid.

[0034] In a preferred embodiment, step (1) is specifically as follows: drying the metallurgical waste slag through a 200-mesh sieve and mixing it with sulfuric acid to obtain a black paste; low-temperature roasting the obtained black paste to obtain a low-temperature roasting product, high-temperature roasting the obtained low-temperature roasting product, and filtering the obtained low-temperature roasting product with water to obtain a filtrate containing manganese sulfate and a leached residue containing Fe2O3; removing impurities from the obtained filtrate containing manganese sulfate to obtain a manganese sulfate solution; stirring and acid leaching the obtained leached residue containing Fe2O3 and adding excess iron powder, filtering to obtain a divalent iron salt solution; mixing the obtained manganese sulfate solution and the divalent iron salt solution to obtain an iron-manganese mixed salt solution; adding nickel salt to the obtained iron-manganese mixed salt solution, adjusting the pH, and obtaining a nickel-iron-manganese mixed salt solution with a desired ratio.

[0035] In a preferred embodiment, in step (1), the content of each element in the metallurgical waste slag satisfies: Fe≥15.6%, Mn≥10.9%, W≤2.5%, Ca≤20.0%, Si≤3.8%, Zn≤0.3%, Sn≤0.7%, Na≤1.2%, S≤1.4%, Al≤0.8%, Pb≤0.3%. Most of the iron and manganese elements in the metallurgical waste slag exist in the form of oxides.

[0036] In a preferred embodiment, in step (1), the mass fraction of sulfuric acid used in the two-stage sulfation roasting is 40-50%; and the mass ratio of the metallurgical waste slag to sulfuric acid is 1:3.2.

[0037] In a preferred embodiment, in step (1), the two-stage sulfation roasting includes low-temperature roasting and high-temperature roasting. The present invention performs two-stage sulfation roasting on metallurgical waste slag, separates and extracts iron and manganese elements from the metallurgical waste slag, and uses the obtained iron and manganese elements to prepare sodium battery precursors, thereby making full use of the metallurgical waste slag, reducing the pollution of the metallurgical waste slag to the environment, improving resource utilization, and realizing the transformation of waste into battery materials.

[0038] In a preferred embodiment, the temperature of the low-temperature roasting is 120-350°C, preferably 180-280°C; the time of the low-temperature roasting is 20-180 minutes, preferably 30-150 minutes. The present invention converts the metal oxides and sulfur elements in the waste residue into stable sulfates through low-temperature roasting.

[0039] In a preferred embodiment, the temperature of the high temperature roasting is 500-800°C, preferably 600-800°C; the time of the high temperature roasting is 50-200min, preferably 60-180min. The present invention decomposes ferrous sulfate into Fe2O3 by high temperature roasting, while manganese sulfate is not decomposed, and the obtained filtrate containing manganese sulfate is removed to obtain a manganese sulfate solution, and the obtained Fe2O3 is converted into divalent iron by oxidation-reduction reaction, thereby obtaining an iron-manganese raw material that can be used to prepare a sodium electric precursor.

[0040] In a preferred embodiment, the temperature of the stirred acid leaching is 25-95° C., and the time is 2-4 hours; the acid used in the stirred acid leaching is sulfuric acid, and the mass fraction of the sulfuric acid is 40-50%; the stirred acid leaching is carried out in an electric constant temperature water bath.

[0041] In a preferred embodiment, in step (1), the nickel salt is nickel sulfate.

[0042] In a preferred embodiment, in step (1), the nickel-iron-manganese mixed salt solution contains nickel salt, divalent iron salt and manganese salt; the molar ratio of the nickel salt, divalent iron salt and manganese salt is x:y:(1-xy), wherein 0.1≤x≤0.5, 0.2≤y≤0.5; and the concentration of the nickel-iron-manganese mixed salt solution is 1.0-3.5 mol / L in terms of metal ion concentration.

[0043] In a preferred embodiment, the pH value of the nickel-iron-manganese mixed salt solution is 4-6.

[0044] In a preferred embodiment, when the molar ratio of nickel salt, divalent iron salt and manganese salt in the nickel-iron-manganese mixed salt solution does not meet x:y:(1-xy), 0.1≤x≤0.5, 0.2≤y≤0.5, the corresponding sulfate is supplemented.

[0045] In a preferred embodiment, step (2) is specifically as follows: a protective gas is introduced into the reactor, and then a base liquid containing a complexing agent is added, and at the same time, the nickel-iron-manganese mixed salt solution obtained in step (1) and a precipitant are added into the reactor in parallel to carry out a co-precipitation reaction. After the co-precipitation reaction is completed, the reaction solution is transferred to an aging kettle for aging, and then alkali-washed, water-washed, dehydrated, dried and sieved to obtain the nickel-iron-manganese-based hydroxide precursor (i.e., sodium positive electrode material precursor).

[0046] In a preferred embodiment, in step (2), the protective gas includes one or more of nitrogen, helium and argon.

[0047] In a preferred embodiment, in step (2), the base liquid containing the complexing agent is composed of oxygen-free water, an antioxidant and a complexing agent; the complexing agent is ammonia water, and the concentration of the ammonia water is 3-8 mol / L; the antioxidant is sodium citrate, sodium thiosulfate or sodium sulfite. The amount of the antioxidant used in the present invention is not particularly limited, as long as it can prevent the oxidation of divalent iron ions.

[0048] In a preferred embodiment, in step (2), the pH value of the base solution containing the complexing agent is 8-13.

[0049] In a preferred embodiment, in step (2), the flow rate of the nickel-iron-manganese mixed salt solution is 1-30 L / h.

[0050] In a preferred embodiment, in step (2), the precipitant is a sodium hydroxide solution; and the concentration of the sodium hydroxide solution is 1-6 mol / L.

[0051] In a preferred embodiment, in step (2), the coprecipitation reaction includes a first stage and a second stage.

[0052] In a preferred embodiment, the first stage is a nucleation stage, and the reaction parameters are: the pH value of the reaction system is 10.00-12.30, the concentration of the complexing agent is 0.06-0.50 mol / L, and the nucleation time is 8-12h; the stirring speed of the first stage is 350-500 rpm / min.

[0053] In a preferred embodiment, the second stage is a growth stage, and the reaction parameters are: the pH value of the reaction system is 9.80-11.00, the concentration of the complexing agent is 0.06-0.50 mol / L, and the growth time is 12-20 hours; the stirring speed of the second stage is 500-850 rpm / min. The concentration of the complexing agent in the first stage and the second stage refers to the concentration of the complexing agent in the entire coprecipitation reaction system.

[0054] In a preferred embodiment, in step (2), the reaction temperature of the coprecipitation reaction is 25-75°C.

[0055] In a preferred embodiment, in step (2), the aging time is 8-16 hours, the temperature is controlled at 25-75° C., and the stirring speed is 400-750 rpm / min.

[0056] In a preferred embodiment, the alkali washing agent is a sodium hydroxide solution at 35-85°C with a concentration of 0.05-15.00 mol / L; the end point of the alkali washing is washing until SO4 2- ≤300ppm.

[0057] In a preferred embodiment, the water washing uses pure water at a temperature of 50-80°C; the end point of the water washing is washing to Na + ≤400ppm.

[0058] In a preferred embodiment, the dehydration method is centrifugal dehydration; the drying method is vacuum drying, and the vacuum degree of the vacuum drying is -150Pa; the mesh size of the sieve used for screening is 325 meshes.

[0059] In a preferred embodiment, in step (2), the D50 of the nickel-iron-manganese-based hydroxide precursor is 4-10 μm, and the SPAN is 0.5-0.8.

[0060] In a preferred embodiment, step (2) adopts a full-process online pH automatic control system consisting of a pH sensor, a peristaltic pump, and a PID regulator.

[0061] In a preferred embodiment, step (3) is specifically as follows: adding barium chloride to the waste liquid generated by washing in step (2) to generate barium sulfate and a mother liquor, wherein the mother liquor is a mixed solution of ammonium chloride and sodium chloride; concentrating the mixed solution of ammonium chloride and sodium chloride once, cooling and filtering the obtained concentrated solution at room temperature to obtain a filtrate and a filter residue; preheating the obtained filtrate and then concentrating it twice, then cooling and crystallizing it to separate ammonium chloride and sodium chloride, and returning the crystallization mother liquor to the first concentration step. The present invention realizes efficient utilization of resources and control of pollutants by harmlessly treating the waste liquid generated in the preparation process and recovering byproducts such as barium sulfate and ammonium chloride.

[0062] In a preferred embodiment, in step (3), the main components of the waste liquid generated by the washing are sodium sulfate and ammonium sulfate.

[0063] In a preferred embodiment, in step (3), the precipitant used for the chemical precipitation is a barium chloride solution; the concentration of the barium chloride solution is 1-3 mol / L.

[0064] In a preferred embodiment, in step (3), SO4 in the mother liquor is detected by TIC-660 ion chromatograph. 2- Concentration, when SO4 in mother liquor 2- Stop adding barium chloride when the concentration is lower than 1 mg / mL.

[0065] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0066] Example 1

[0067] A method for preparing a sodium electrode precursor with high tap density in an efficient and resource-saving manner. The process flow is shown in Figure 1 , the specific steps are as follows:

[0068] (1) The dried metallurgical waste slag is passed through a 200-mesh sieve and then mixed with a 40% sulfuric acid solution in a mass ratio of 1:3.2 in a porcelain crucible to obtain a black paste; the obtained black paste is placed in a muffle furnace and roasted at 180° C. for 30 minutes to obtain a low-temperature roasted product; the obtained low-temperature roasted product is placed in a muffle furnace again and roasted at 600° C. for 60 minutes, and after water leaching and filtration, a filtrate containing manganese sulfate and a leached residue containing Fe2O3 are obtained; the obtained filtrate containing manganese sulfate is The method comprises the following steps: obtaining a manganese sulfate solution after removing impurities; mixing the obtained leached residue containing Fe2O3 with sulfuric acid and excess iron powder, placing the mixture in an electric constant temperature water bath, stirring and acid leaching for 2 hours at 60°C, and filtering to obtain a divalent iron sulfate solution; mixing the above manganese sulfate solution and the divalent iron sulfate solution to obtain an iron-manganese mixed sulfate solution; adding nickel sulfate to the obtained iron-manganese mixed sulfate solution, adjusting the pH value, and obtaining a nickel-iron-manganese mixed sulfate solution, wherein the molar ratio of nickel salt, divalent iron salt and manganese salt in the nickel-iron-manganese mixed sulfate solution is Ni: 0.33 Fe 0.33 Mn 0.33 , the pH value of the nickel-iron-manganese mixed sulfate solution is 4, and the concentration of the nickel-iron-manganese mixed sulfate solution is 1.0 mol / L in terms of metal ion concentration; if the ratio of nickel salt, divalent iron salt and manganese salt in the nickel-iron-manganese mixed sulfate solution after the reaction does not reach the above molar ratio, then supplement the corresponding sulfates;

[0069] Among them, most of the iron and manganese in metallurgical waste slag exist in the form of oxides, and the content of each element meets the following requirements: Fe≥15.6%, Mn≥10.9%, W≤2.5%, Ca≤20.0%, Si≤3.8%, Zn≤0.3%, Sn≤0.7%, Na≤1.2%, S≤1.4%, Al≤0.8%, and Pb≤0.3%.

[0070] (2) adopting a full-process online pH automatic control system composed of a pH sensor, a peristaltic pump, and a PID regulator; introducing nitrogen into the reactor, and then adding a mixed solution composed of oxygen-free water, sodium citrate and ammonia water as a base liquid, and at the same time, adding the nickel-iron-manganese mixed sulfate solution prepared in step (1) and a sodium hydroxide solution with a concentration of 3 mol / L to the base liquid at a flow rate of 5 L / h to carry out a co-precipitation reaction. After the co-precipitation reaction is completed, the reaction solution is transferred to an aging kettle, aged at 45° C. and 400 rpm / min for 8 hours, and then washed with a sodium hydroxide solution at a concentration of 1.00 mol / L at 35° C. to remove SO4 2- ≤300ppm, then wash with 70℃ pure water until Na +≤400ppm, after centrifugal dehydration, place in a vacuum oven, adjust the vacuum degree to -150Pa, dry and dehydrate, pass through a 325 mesh sieve, and obtain a nickel-iron-manganese-based hydroxide precursor, that is, a high tap density sodium electrode precursor, the D50 of the nickel-iron-manganese-based hydroxide precursor is 4-10μm, and the SPAN is 0.5-0.8;

[0071] The pH of the base solution is 11, and the concentration of ammonia in the base solution is 3 mol / L;

[0072] The temperature of the coprecipitation reaction is 55°C; the coprecipitation reaction is divided into a first stage and a second stage. The reaction parameters of the first stage are: the pH value of the reaction system is 11.00, the nucleation time is 12h, and the stirring speed is 350rpm / min; the reaction parameters of the second stage are: the pH value of the reaction system is 10.50, the growth time is 20h, and the stirring speed is 500rpm / min.

[0073] (3) adding barium chloride with a concentration of 1 mol / L to the waste liquid generated by alkali washing and water washing in step (2); the ammonium sulfate and sodium sulfate in the waste liquid react with the barium chloride to generate a by-product barium sulfate and a mother liquor, wherein the mother liquor is a mixed solution of ammonium chloride and sodium chloride; and detecting SO4 in the mother liquor by a TIC-660 ion chromatograph. 2- Concentration, when SO4 2- When the concentration is lower than 1 mg / mL, stop adding barium chloride; pump the mixed solution of ammonium chloride and sodium chloride into an evaporator for primary concentration, cool and filter the concentrated solution at room temperature to obtain a filtrate and a filter residue; preheat the filtrate and then enter the evaporator again for secondary concentration, then cool and crystallize to separate ammonium chloride and sodium chloride, and return the crystallization mother liquor to the primary concentration step.

[0074] The SEM image of the high tap density sodium electrode precursor obtained in this example is as follows: Figure 2 As shown. Figure 2 It can be seen that the high tap density sodium electrode precursor obtained in the embodiment of the present invention is spherical and has a high degree of sphericity.

[0075] Example 2

[0076] A method for preparing a sodium electrode precursor with high tap density in an efficient and resource-saving manner. The process flow is shown in Figure 1 , the specific steps are as follows:

[0077] (1) The dried metallurgical waste slag is passed through a 200-mesh sieve and then mixed with a 40% sulfuric acid solution in a mass ratio of 1:3.2 in a porcelain crucible to obtain a black paste; the obtained black paste is placed in a muffle furnace and roasted at 180° C. for 30 minutes to obtain a low-temperature roasted product; the obtained low-temperature roasted product is placed in a muffle furnace again and roasted at 600° C. for 60 minutes, and after water leaching and filtration, a filtrate containing manganese sulfate and a leached residue containing Fe2O3 are obtained; the obtained filtrate containing manganese sulfate is The method comprises the following steps: obtaining a manganese sulfate solution after removing impurities; mixing the obtained leached residue containing Fe2O3 with sulfuric acid and excess iron powder, placing the mixture in an electric constant temperature water bath, stirring and acid leaching for 2 hours at 60°C, and filtering to obtain a divalent iron sulfate solution; mixing the above manganese sulfate solution and the divalent iron sulfate solution to obtain an iron-manganese mixed sulfate solution; adding nickel sulfate to the obtained iron-manganese mixed sulfate solution, adjusting the pH value, and obtaining a nickel-iron-manganese mixed sulfate solution, wherein the molar ratio of nickel salt, divalent iron salt and manganese salt in the nickel-iron-manganese mixed sulfate solution is Ni: 0.33 Fe 0.33 Mn 0.33 , the pH value of the nickel-iron-manganese mixed sulfate solution is 4, and the concentration of the nickel-iron-manganese mixed sulfate solution is 1.0 mol / L in terms of metal ion concentration; if the ratio of nickel salt, divalent iron salt and manganese salt in the nickel-iron-manganese mixed sulfate solution after the reaction does not reach the above molar ratio, then supplement the corresponding sulfates;

[0078] Among them, most of the iron and manganese in metallurgical waste slag exist in the form of oxides, and the content of each element meets the following requirements: Fe≥15.6%, Mn≥10.9%, W≤2.5%, Ca≤20.0%, Si≤3.8%, Zn≤0.3%, Sn≤0.7%, Na≤1.2%, S≤1.4%, Al≤0.8%, and Pb≤0.3%.

[0079] (2) adopting a full-process online pH automatic control system composed of a pH sensor, a peristaltic pump, and a PID regulator; introducing nitrogen into the reactor, and then adding a mixed solution composed of oxygen-free water, sodium citrate and ammonia water as a base liquid, and at the same time, adding the nickel-iron-manganese mixed sulfate solution prepared in step (1) and a sodium hydroxide solution with a concentration of 4 mol / L to the base liquid at a flow rate of 4 L / h to carry out a co-precipitation reaction. After the co-precipitation reaction is completed, the reaction solution is transferred to an aging kettle, aged at 50° C. and 500 rpm / min for 10 hours, and then washed with a sodium hydroxide solution at a concentration of 1.00 mol / L at 35° C. to remove SO4 2- ≤300ppm, then wash with 70℃ pure water until Na +≤400ppm, after centrifugal dehydration, place in a vacuum oven, adjust the vacuum degree to -150Pa, dry and dehydrate, pass through a 325 mesh sieve, and obtain a nickel-iron-manganese-based hydroxide precursor, that is, a high tap density sodium electrode precursor, the D50 of the nickel-iron-manganese-based hydroxide precursor is 4-10μm, and the SPAN is 0.5-0.8;

[0080] The pH of the base solution is 10, and the concentration of ammonia in the base solution is 4 mol / L;

[0081] The temperature of the coprecipitation reaction is 60°C; the coprecipitation reaction is divided into a first stage and a second stage. The reaction parameters of the first stage are: the pH value of the reaction system is 10.00, the ammonia concentration is 0.08 mol / L, the nucleation time is 10 h, and the stirring speed is 400 rpm / min; the reaction parameters of the second stage are: the pH value of the reaction system is 9.80, the ammonia concentration is 0.08 mol / L, the growth time is 18 h, and the stirring speed is 600 rpm / min.

[0082] (3) adding barium chloride with a concentration of 1 mol / L to the waste liquid generated by alkali washing and water washing in step (2); the ammonium sulfate and sodium sulfate in the waste liquid react with the barium chloride to generate a by-product barium sulfate and a mother liquor, wherein the mother liquor is a mixed solution of ammonium chloride and sodium chloride; and detecting SO4 in the mother liquor by a TIC-660 ion chromatograph. 2- Concentration, when SO4 2- When the concentration is lower than 1 mg / mL, stop adding barium chloride; pump the mixed solution of ammonium chloride and sodium chloride into an evaporator for primary concentration, cool and filter the concentrated solution at room temperature to obtain a filtrate and a filter residue; preheat the filtrate and then enter the evaporator again for secondary concentration, then cool and crystallize to separate ammonium chloride and sodium chloride, and return the crystallization mother liquor to the primary concentration step.

[0083] Example 3

[0084] The difference from Example 1 is that in step (2), the pH value of the first-stage reaction system is 10.50, and the pH value of the second-stage reaction system is 10.30. The rest is the same as Example 1.

[0085] Example 4

[0086] The difference from Example 1 is that in step (2), the pH value of the first-stage reaction system is 12.00, and the pH value of the second-stage reaction system is 11.00. The rest is the same as Example 1.

[0087] Example 5

[0088] The difference from Example 1 is that in step (2), the temperature of the coprecipitation reaction is 40° C., and the rest is the same as Example 1.

[0089] Example 6

[0090] The difference from Example 1 is that in step (2), the temperature of the coprecipitation reaction is 70° C., and the rest is the same as Example 1.

[0091] Example 7

[0092] The difference from Example 1 is that in step (2), the stirring speed in the first stage is 500 rpm / min, and the stirring speed in the second stage is 800 rpm / min, and the rest is the same as Example 1.

[0093] Example 8

[0094] The difference from Example 1 is that in step (2), the stirring speed in the first stage is 450 rpm / min, and the stirring speed in the second stage is 700 rpm / min, and the rest is the same as Example 1.

[0095] Comparative Example 1

[0096] The difference from Example 1 is that in step (2), the temperature of the coprecipitation reaction is 90° C., and the rest is the same as Example 1.

[0097] Comparative Example 2

[0098] The difference from Example 1 is that in step (2), the stirring speed in the first stage is 500 rpm / min, and the stirring speed in the second stage is 500 rpm / min, and the rest is the same as Example 1.

[0099] Comparative Example 3

[0100] The difference from Example 1 is that in step (2), the stirring speed in the first stage is 250 rpm / min, and the stirring speed in the second stage is 900 rpm / min, and the rest is the same as Example 1.

[0101] Performance Characterization

[0102] The sphericity and tap density of the high tap density sodium electrolyte precursors prepared in Examples 1-8 and Comparative Examples 1-3 were measured. The results are shown in Table 1.

[0103] Table 1

[0104]

[0105]

[0106] It can be seen from Table 1 that the sphericity of the high tap density sodium electrode precursor obtained in the embodiment of the present invention can reach 0.923, and the tap density can reach 1.75 g / cm 3Compared with Example 1, Comparative Example 1 changed the temperature of the coprecipitation reaction, and Comparative Examples 2 and 3 changed the stirring speeds of the first stage and the second stage, and the sphericity and tap density of the obtained sodium electrode precursor decreased to varying degrees.

[0107] The above are only preferred specific embodiments 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 a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for efficiently and resourcefully preparing a high tap density sodium electrode precursor, characterized in that: The following steps are involved: (1) subjecting metallurgical waste slag to two-stage sulfuric acid roasting, separating and extracting iron and manganese elements, and supplementing nickel salt to obtain a nickel-iron-manganese mixed salt solution; (2) under a protective atmosphere, adding the nickel-iron-manganese mixed salt solution obtained in step (1) and a precipitant in parallel to a base liquid containing a complexing agent to carry out a coprecipitation reaction, and then aging, washing and drying to obtain a nickel-iron-manganese-based hydroxide precursor; (3) chemically precipitating and evaporating the waste liquid generated by washing in step (2) to complete the recycling of the waste liquid.

2. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (1), the contents of each element in the metallurgical waste slag satisfy the following requirements: Fe≥15.6%, Mn≥10.9%, W≤2.5%, Ca≤20.0%, Si≤3.8%, Zn≤0.3%, Sn≤0.7%, Na≤1.2%, S≤1.4%, Al≤0.8%, and Pb≤0.3%.

3. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (1), the two-stage sulfation roasting includes low-temperature roasting and high-temperature roasting; the temperature of the low-temperature roasting is 120-350°C and the time is 20-180 minutes; the temperature of the high-temperature roasting is 500-800°C and the time is 50-200 minutes.

4. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (1), the mass fraction of sulfuric acid used in the two-stage sulfation roasting is 40-50%.

5. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (1), the nickel-iron-manganese mixed salt solution contains nickel salt, divalent iron salt and manganese salt; the molar ratio of the nickel salt, divalent iron salt and manganese salt is x:y:(1-xy), wherein 0.1≤x≤0.5, 0.2≤y≤0.5; and the concentration of the nickel-iron-manganese mixed salt solution is 1.0-3.5 mol / L in terms of metal ion concentration.

6. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (2), the precipitant is a sodium hydroxide solution; the concentration of the sodium hydroxide solution is 1-6 mol / L.

7. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (2), the base liquid containing the complexing agent is composed of oxygen-free water, an antioxidant and a complexing agent; and the complexing agent is ammonia water.

8. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (2), the coprecipitation reaction includes a first stage and a second stage; The first stage is the nucleation stage, and the reaction parameters are: the pH value of the reaction system is 10.00-12.30, the concentration of the complexing agent is 0.06-0.50 mol / L, and the nucleation time is 8-12h; The second stage is the growth stage, and the reaction parameters are: the pH value of the reaction system is 9.80-11.00, the concentration of the complexing agent is 0.06-0.50 mol / L, and the growth time is 12-20 hours.

9. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (2), the D50 of the nickel-iron-manganese-based hydroxide precursor is 4-10 μm, and the SPAN is 0.5-0.

8.

10. The method for preparing a sodium-ion battery precursor with high tap density in an efficient and resource-saving manner according to claim 1, characterized in that: In step (3), the precipitant used for the chemical precipitation is a barium chloride solution; the concentration of the barium chloride solution is 1-3 mol / L.

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