Method for efficiently preparing battery-grade manganous-manganic oxide from electrolytic manganese residue leachate and harmless treatment method for tail liquid of battery-grade manganous-manganic oxide

Abstract

The invention relates to the field of preparation of battery materials and precursors of the battery materials, and discloses a method for efficiently preparing battery-grade manganous-manganic oxide by using electrolytic manganese residue leachate and a harmless treatment method for tail liquid of the battery-grade manganous-manganic oxide. Treating the manganese residue leachate concentrated water obtained in the previous step with ammonia water and oxygen to prepare battery-grade manganous-manganic oxide; adjusting the pH value of the filtrate obtained in the previous step to prepare magnesium hydroxide; the filtrate obtained in the previous step is subjected to evaporative crystallization, ammonium sulfate is prepared, finally, harmless treatment of preparation of battery-grade manganous-manganic oxide from the manganese residue leachate and the tail liquid of the battery-grade manganous-manganic oxide is achieved, and the recovery efficiency of valuable components is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of preparation of battery materials and their precursors, and specifically to a method for efficiently preparing battery-grade manganese tetraoxide from electrolytic manganese residue leachate and a method for harmless treatment of the tail liquid thereof. Background Art

[0002] Electrolytic manganese residue is a high-moisture industrial solid waste generated during the production of electrolytic manganese metal, which contains a large amount of soluble manganese sulfate and ammonium sulfate. The main chemical components of electrolytic manganese residue are CaSO4, SiO2, Al2O3, Fe2O3, MnO and SO3, etc., and its phase composition is mainly gypsum dihydrate and silicon dioxide. The contents of manganese and ammonia nitrogen in electrolytic manganese residue are relatively high, and the highest contents reach 34762 mg / kg and 2987 mg / kg respectively. In addition, it also contains sulfates, and its content is as high as 38378 mg / kg. For electrolytic manganese enterprises, electrolytic manganese residue is mostly treated by stacking or direct landfill, and a large amount of leachate containing high concentrations of heavy metals and ammonia nitrogen will be generated during the stacking process of electrolytic manganese residue, which has caused serious pollution to the surface water, groundwater, rivers, etc. around electrolytic manganese enterprises. At present, a large number of studies have been carried out on the harmless treatment of electrolytic manganese residue leachate in China. For example, the method described in the patent "CN106186455A" realizes the harmless treatment of electrolytic manganese residue leachate by sequentially adding saturated clarified lime water, sodium silicate, sodium chloride and an electric field, but this method has a complex process flow and high cost; the patent "CN106242180A" discloses a device and method for deep treatment and reuse of electrolytic manganese residue leachate. This method uses an iron filings microelectrolysis bed to remove chromium in electrolytic manganese residue leachate, a stripping tower to remove ammonia nitrogen, a reaction tank and an inclined tube sedimentation tank to remove heavy metal ions, and a microbial manganese removal tank to remove manganese. This method has clear functions, thoroughly removes heavy metal pollutants, is ecologically friendly and has no secondary pollution, but its reaction process is complex, the conditions are strict, and the device is complex. Therefore, the present invention proposes a method for efficiently preparing battery-grade manganese tetraoxide from electrolytic manganese residue leachate and a method for harmless treatment of the tail liquid thereof. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for efficiently preparing battery-grade manganese tetraoxide from electrolytic manganese residue leachate and a method for harmless treatment of the tail liquid thereof, so as to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solutions: A method for efficiently preparing battery-grade manganese tetraoxide from electrolytic manganese residue leachate and a method for harmless treatment of the tail liquid thereof, including the following steps:

[0005] Step 1, take a certain amount of electrolytic manganese residue leachate, and concentrate the leachate by using an ion membrane. After the electrolytic manganese residue leachate passes through the ion membrane concentration treatment process, an electrolytic manganese residue leachate concentrate is obtained;

[0006] Step 2: Take a certain amount of concentrated electrolytic manganese residue leachate, use a small amount of it as the reaction bottom liquid, and add the concentrated leachate and the alkaline precipitant to the flask with the reaction bottom liquid in a co-current manner. Control the reaction temperature at 25 - 90 °C, and introduce an oxidizing gas into the reaction system. By controlling the flow rate of the precipitant, adjust the pH of the reaction system to be between 7.0 - 8.5, and the reaction time is 4 - 16 h. After filtration, washing, and drying, battery-grade manganese tetroxide is obtained, and the filtrate is recovered;

[0007] Step 3: Collect the filtrate obtained in Step 2 above, add ammonia water to adjust the pH to 8.5 - 11.0, precipitate Mg in the leachate in the form of Mg(OH)₂, and obtain the Mg(OH)₂ precipitate after filtration, and recover the filtrate;

[0008] Step 4: Perform ion membrane concentration treatment on the filtrate obtained in Step 3 to obtain a concentrated filtrate of the filter tail liquid;

[0009] Step 5: Perform evaporation crystallization on the concentrated filtrate of the filter tail liquid obtained in Step 4 to obtain (NH₄)₂SO₄ crystals.

[0010] Preferably: The ion membrane for concentrating the leachate in Step 1 refers to manganese solution ion concentration, including but not limited to ion exchange membranes and nanofiltration membranes. The types of manganese ion exchange concentration membranes include but are not limited to heterogeneous ion exchange membranes, homogeneous ion exchange membranes, and semi-homogeneous ion exchange membranes. The types of nanofiltration membranes include but are not limited to polyamide nanofiltration membranes, sulfonated polysulfone and sulfonated polyethersulfone nanofiltration membranes, composite nanofiltration membranes, intelligent responsive nanofiltration membranes, etc.

[0011] Preferably: The oxidizing gas in Step 2 includes but is not limited to air and oxygen.

[0012] Preferably: For the manganese tetroxide obtained in Step 2, after mixing it evenly with lithium carbonate, it is sintered at high temperature in a muffle furnace to prepare a lithium manganese oxide cathode material, which can be used as a cathode material for lithium-ion batteries.

[0013] Preferably: The main component of the precipitate obtained in Step 3 is Mg(OH)₂, which is dissolved in dilute sulfuric acid to prepare MgSO₄.

[0014] Preferably: The ion membrane for concentrating the filter tail liquid in Step 4 refers to manganese solution ion concentration, including but not limited to ion exchange membranes and nanofiltration membranes. The types of manganese ion exchange concentration membranes include but are not limited to heterogeneous ion exchange membranes, homogeneous ion exchange membranes, and semi-homogeneous ion exchange membranes. The types of nanofiltration membranes include but are not limited to polyamide nanofiltration membranes, sulfonated polysulfone and sulfonated polyethersulfone nanofiltration membranes, composite nanofiltration membranes, intelligent responsive nanofiltration membranes, etc.

[0015] Preferably, the tail liquid concentrate obtained in the fifth step is evaporated and crystallized at 70-90 °C to obtain ammonium sulfate.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] The present invention not only realizes the efficient recovery of manganese resources during the treatment of electrolytic manganese residue leachate, but also provides dual economic and environmental benefits for wastewater treatment through the generation of a series of by-products (such as magnesium hydroxide, magnesium sulfate, ammonium sulfate, etc.). Among them, the recovery rates of Mn and Mg in the present invention can reach 98.47%. Its comprehensive resource recovery and environmental protection treatment characteristics not only enhance the economic value of the process, but also make a positive contribution to the realization of zero discharge of industrial wastewater and resource recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the process flow chart of the present invention;

[0019] Figure 2 is the X-ray diffraction (XRD) comparison spectrum of Example 1 of the present invention;

[0020] Figure 3 is the scanning electron microscope (SEM) image of Example 1 of the present invention;

[0021] Figure 4 is the charge-discharge curve of Example 1 of the present invention under the charge-discharge conditions of 3.0-4.3 V in the first cycle at 0.1C. DETAILED DESCRIPTION OF THE INVENTION

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] Please refer to Figures 1-4 , a method for efficiently preparing battery-grade manganese tetroxide from electrolytic manganese residue leachate and a method for harmless treatment of its tail liquid in the figure, including the following steps:

[0024] Step 1: Take 1500 ml of electrolytic manganese residue leachate, and concentrate the leachate using an ion membrane. After the ion membrane concentration treatment process, the concentrated water of the electrolytic manganese residue leachate is obtained.

[0025] Step 2: Take 800 ml of electrolytic manganese slag leachate with a Mn mass concentration of 5 - 20 g / L and a Mg mass concentration of 5 - 15 g / L. Use 200 ml of it as the reaction bottom liquid. Add 600 ml of leachate and 60 ml of a 13% precipitant to the flask with the reaction bottom liquid in a co-current manner. Control the reaction temperature at 25 - 90 °C, and introduce an oxidizing gas into the reaction system. Adjust the pH of the reaction system to be between 7.3 - 8.0 by controlling the flow rate of the precipitant to precipitate manganese tetroxide. After filtration, washing, and drying, battery-grade manganese tetroxide is obtained, and the filtrate is recycled;

[0026] Step 3: Mix the manganese tetroxide obtained in Step 2 with lithium carbonate according to the chemical formula of LiMn2O4 in a stoichiometric ratio with 5% excess Li. Mix them evenly and sinter at 780 °C in a muffle furnace to obtain the lithium manganese oxide cathode material;

[0027] Step 4: Take 500 ml of the filtrate obtained in Step 2 above, add ammonia water to adjust the pH to 8.0 - 9.0 to precipitate Mg in the leachate in the form of Mg(OH)2. After filtration, the Mg(OH)2 precipitate is obtained, and the filtrate is recycled;

[0028] Step 5: Take 5 g of the Mg(OH)2 precipitate obtained in Step 4 above and dissolve it in 50 ml of 20% by mass dilute sulfuric acid to obtain a MgSO4 solution;

[0029] Step 6: Take 500 ml of the filtrate obtained in Step 4 above for ion membrane concentration treatment to obtain concentrated filtrate;

[0030] Step 7: Take the concentrated filtrate obtained in Step 6 above for evaporation crystallization to obtain (NH4)2SO4 crystals.

[0031] A typical case of the electrolytic manganese slag leachate treatment method of the present invention is shown in Comparative Example 1:

[0032] Comparative Example 1

[0033] When the mass concentration of Mn in the initial manganese slag leachate is 12.45 g / L and the mass concentration of Mg is 8.9 g / L, 800 ml of the manganese slag leachate is taken. Using 200 ml of the manganese slag leachate as the reaction bottom liquid, the remaining 600 ml of the leachate and ammonia water with a mass concentration of 13% are added to the reaction system in a co-current manner. The reaction temperature is 70 °C, the stirring rate is 400 rpm, the reaction time lasts for 8 h, the oxidation atmosphere is oxygen, and the pH during the reaction process is controlled at 7.8 to obtain manganese tetraoxide with a manganese recovery rate of 85%; 1000 ml of the filtrate from Step 1 is collected, ammonia water with a concentration of 13% is added to it, and the pH is adjusted to 8.2 to obtain magnesium hydroxide precipitate with a magnesium recovery rate of 80.1%; the filtrate from Step 2 is evaporated and concentrated at 90 °C to obtain ammonium sulfate crystals.

[0034] Example 1

[0035] When the mass concentration of Mn in the initial manganese slag leachate is 12.45 g / L and the mass concentration of Mg is 8.9 g / L, the initial manganese slag leachate is subjected to membrane concentration treatment according to the above steps, so that the mass concentration of Mn is 82.05 g / L and the mass concentration of Mg is 58.65 g / L. Similarly, 800 ml of the concentrated manganese slag leachate is taken, and manganese tetraoxide is prepared by the method of Comparative Example 1 with a manganese recovery rate of 98.15%; the pH in Step 4 is adjusted to 8.5, and the magnesium recovery rate is 92.07%.

[0036] Example 2

[0037] Compared with Example 1, the difference is only that the degree of membrane concentration of the manganese slag leachate in Step 1 is changed, and the experimental groups are as follows:

[0038] Group A: The mass concentration of Mn is 20 g / L and the mass concentration of Mg is 14.28 g / L.

[0039] Group B: The mass concentration of Mn is 54.7 g / L and the mass concentration of Mg is 39.1 g / L.

[0040] Group C: The mass concentration of Mn is 109.4 g / L and the mass concentration of Mg is 78.21 g / L.

[0041] Other operations and parameters are the same as in Example 1.

[0042] Example 3

[0043] Compared with Example 1, the difference is only that the reaction temperature in Step 1 is changed, and the experimental groups are as follows:

[0044] A: The reaction temperature is 50 °C, and other operations and parameters are the same as in Example 1;

[0045] B: The reaction temperature is 60 °C, and other operations and parameters are the same as in Example 1;

[0046] C: The reaction temperature is 80 °C, and other operations and parameters are the same as in Example 1;

[0047] Other operations and parameters are the same as in Example 1.

[0048] Example 4

[0049] Compared with Example 1, the difference is only that the pH control of the reaction in Step 1 is changed. The experimental groups are as follows:

[0050] A: The reaction pH is 7.3, and other operations and parameters are the same as in Example 1;

[0051] B: The reaction pH is 7.6, and other operations and parameters are the same as in Example 1;

[0052] C: The reaction pH is 8.0, and other operations and parameters are the same as in Example 1;

[0053] Example 5

[0054] Compared with Example 1, the difference is only that the pH control of the reaction in Step 2 is changed. The experimental groups are as follows:

[0055] A: The reaction pH is 8.3, and other operations and parameters are the same as in Example 1;

[0056] B: The reaction pH is 8.7, and other operations and parameters are the same as in Example 1;

[0057] C: The reaction pH is 9.0, and other operations and parameters are the same as in Example 1;

[0058] The ICP data of the electrolytic manganese slag leachate and the manganese tetroxide prepared in Example 1 are shown in Table 1:

[0059] Table 1 ICP data of electrolytic manganese slag leachate and manganese tetroxide

[0060]

[0061] The ICP physical and chemical indexes of the manganese tetroxide prepared from the electrolytic manganese slag leachate meet the industry standards of battery-grade manganese tetroxide. The Mn and Mg recovery efficiency data of the above examples and comparative examples are shown in Table 2:

[0062] Table 2 Mn and Mg recovery efficiency data of specific cases

[0063]

[0064]

[0065] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0066] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for efficiently preparing battery-grade manganese tetraoxide using electrolytic manganese slag leachate and a method for harmless treatment of tail liquid thereof, characterized in that: The steps include: Step 1, taking a certain amount of electrolytic manganese slag leachate, and concentrating the leachate using an ion membrane, wherein the manganese slag leachate is concentrated by the ion membrane to obtain a manganese slag leachate concentrate; Step 2, taking a certain amount of electrolytic manganese slag leachate concentrate, using a small amount of it as a reaction base liquid, adding the leachate concentrate and an alkaline solution precipitant to a flask with the reaction base liquid in parallel, controlling the reaction temperature to 25-90° C., and introducing an oxidizing gas into the reaction system, by controlling the flow rate of the precipitant, adjusting the pH of the reaction system to between 7.0 and 8.5, the reaction time is 4-16 hours, filtering, washing and drying to obtain battery-grade manganese tetraoxide, and recovering the filtrate; Step 3, collecting the filtrate obtained in the above step 2, adding ammonia water thereto to adjust the pH to 8.5-11.0, precipitating the Mg in the filtrate in the form of Mg(OH)2, obtaining the Mg(OH)2 precipitate after filtration, and recovering the filtrate; Step 4, subjecting the filtrate obtained in step 3 to ion membrane concentration treatment to obtain filtrate tail liquid concentrate; Step 5, evaporating and crystallizing the concentrated water of the filtered tail liquid obtained in step 4 to obtain (NH4)2SO4 crystals.

2. The method for efficiently preparing battery-grade manganese tetraoxide by utilizing electrolytic manganese slag leachate and the harmless treatment method of the tail liquid thereof according to claim 1, characterized in that: The ion membrane used to concentrate the leachate in step 1 refers to a manganese liquid ion concentration membrane, including but not limited to an ion exchange membrane and a nanofiltration membrane. The types of manganese ion exchange concentration membranes include but are not limited to heterogeneous ion exchange membranes, homogeneous ion exchange membranes and semi-homogeneous ion exchange membranes. The types of nanofiltration membranes include but are not limited to polyamide nanofiltration membranes, sulfonated polysulfone and sulfonated polyethersulfone nanofiltration membranes, composite nanofiltration membranes, intelligent response nanofiltration membranes, etc.

3. The method for efficiently preparing battery-grade manganese tetraoxide by utilizing electrolytic manganese slag leachate and the harmless treatment method of the tail liquid thereof according to claim 2, characterized in that: The oxidizing gas in step 2 includes but is not limited to air and oxygen.

4. The method for efficiently preparing battery-grade manganese tetraoxide by utilizing electrolytic manganese slag leachate and the harmless treatment method of the tail liquid thereof according to claim 3, characterized in that: The manganese tetraoxide obtained in step 2 is mixed evenly with lithium carbonate and then sintered at high temperature in a muffle furnace to prepare a lithium manganate positive electrode material, which can be used as a positive electrode material for lithium ion batteries.

5. The method for efficiently preparing battery-grade manganese tetraoxide by utilizing electrolytic manganese slag leachate and the harmless treatment method of tail liquid thereof according to claim 4, characterized in that: The main component of the precipitate obtained in step three is Mg(OH)2, which is dissolved in dilute sulfuric acid to prepare MgSO4.

6. The method for efficiently preparing battery-grade manganese tetraoxide by utilizing electrolytic manganese slag leachate and the harmless treatment method of the tail liquid thereof according to claim 5, characterized in that: The filtrate obtained in step 4 is concentrated by an ion membrane to obtain a tail liquid concentrate.

7. The method for efficiently preparing battery-grade manganese tetraoxide by utilizing electrolytic manganese slag leachate and the harmless treatment method of the tail liquid thereof according to claim 6, characterized in that: The tail liquid concentrate obtained in step 6 is evaporated and crystallized at 70-90° C. to obtain ammonium sulfate.

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