Production process of electrolytic manganese dioxide

Abstract

The invention discloses a production process of electrolytic manganese dioxide, and belongs to the technical field of electrolytic manganese dioxide preparation processes, and the production process comprises the following steps: 1, disassembling and sorting waste lithium ion batteries, recovering heavy metal elements, separating to obtain a solution mainly containing Mn < 2 + > ions, adjusting the pH value to 3-3.5, adding an extracting agent to extract the Mn < 2 + > ions, and carrying out back extraction to obtain a solution containing the Mn < 2 + > ions; 2, adjusting the concentration of sulfuric acid in the solution to obtain an electrolyte; the electrolysis process occurs in the diaphragm electrolytic cell, the cathode plate and the anode plate are respectively arranged on two sides of the proton exchange membrane diaphragm, electrolyte is introduced into the anode chamber, and ammonia water is introduced into the cathode chamber; electrolyte at the temperature of 40-50 DEG C is introduced into an anode chamber for electrolysis, the anode current density is 50-60 A / m < 2 >, and the cell voltage is 1.5-2 V; and step 3, taking out of the tank after electrolysis, crushing, rinsing, grinding and drying to prepare the electrolytic manganese dioxide. The purity and the current efficiency of the electrolytic manganese dioxide product can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic manganese dioxide preparation technology, and more specifically, to a production process of electrolytic manganese dioxide. Background Art

[0002] Electrolytic manganese dioxide is an important chemical product and an important chemical raw material. It can be used in medicine, papermaking, battery raw materials and the preparation of other manganese salts. The production principle of electrolytic manganese dioxide is to oxidize manganese ions into manganese dioxide through the electrolysis process using the action of electric current. In the electrolytic production process, the raw materials are dissolved, purified, electrolyzed and other steps to generate manganese dioxide, and then stripped, crushed, rinsed, neutralized, dried and other treatments to obtain electrolytic manganese dioxide products. The raw materials required for the production of electrolytic manganese dioxide are usually manganese ore. There are fewer and fewer high-grade manganese ore resources in the current industry market. It is urgent to reduce the excessive use of manganese ore resources, expand the raw materials required for the production of electrolytic manganese dioxide, reduce environmental pollution, improve purity, and improve the utilization of resources and energy, etc., to meet the production needs of electrolytic manganese dioxide.

[0003] In this regard, the prior art discloses a method for recovering manganese and copper resources from waste lithium-ion batteries (Announcement No. CN104037468B), which separates waste lithium-ion batteries to obtain a solution mainly containing Cu2+ and Mn2+ ions as a raw material, and uses a copper sheet as a cathode and a graphite sheet as an anode for electrolysis to obtain manganese dioxide and copper. Although two products are obtained, in actual production, the presence of copper ions and other metal ions will not only have a negative impact on the purity of the electrolytic manganese dioxide product, but also affect the electrochemical properties of the electrolytic manganese dioxide, as well as the output rate of manganese dioxide. Summary of the invention

[0004] The purpose of the present invention is to provide a production process of electrolytic manganese dioxide, which is obtained by disassembling, sorting and separating waste lithium-ion batteries to obtain electrolytic manganese dioxide mainly containing Mn 2+ ion solution, and then use the extractant to remove Mn 2+ Loaded in the organic phase, and then stripped Mn 2+ In the water phase, the influence of other metal ions on the purity and electrochemical performance of electrolytic manganese dioxide products is reduced. And the reaction of ammonia water in the cathode chamber is formed by using the proton exchange membrane as a diaphragm, which can not only reduce the side reaction of hydrogen evolution, but also improve the current efficiency, reduce the electrolysis temperature, reduce energy consumption, and improve the utilization effect of resources and energy.

[0005] In order to achieve these objects of the present invention, the present invention provides a production process of electrolytic manganese dioxide, comprising: Step 1: Disassemble and sort the waste lithium-ion batteries, recover the heavy metal elements, and then separate the main Mn 2+ion solution, add sulfuric acid to adjust the solution pH to 3~3.5, and then add the extractant to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ A first solution of ions; Step 2: adding sulfuric acid to the first solution, adjusting the concentration of sulfuric acid in the solution to 0.2-2 mol / L, and obtaining an electrolyte; the electrolysis process occurs in a diaphragm electrolytic cell, the cathode plate and the anode plate are arranged on both sides of the diaphragm, the bottom of the cell on both sides of the diaphragm are provided with a liquid inlet, and the cell wall is provided with a liquid outlet, the electrolyte is introduced into the anode chamber, and the ammonia water is introduced into the cathode chamber; wherein the anode plate is a titanium-manganese alloy electrode, the cathode plate is a copper plate, and the diaphragm is a proton exchange membrane; the electrolysis process continuously discharges waste liquid and replenishes new liquid, the anode chamber is electrolyzed by passing the electrolyte at 40-50°C, and the anode current density is 50-60A / m 2 , cell voltage 1.5~2V; Step 3: After electrolysis, the mixture is discharged from the tank, crushed, rinsed, ground and dried to obtain electrolytic manganese dioxide.

[0006] Preferably, in step 1, an extractant is added to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ The specific method of the first solution of ions is: Take di(2-ethylhexyl) phosphate, sodium hydroxide solid and kerosene for saponification, then place in a 60℃ constant temperature water bath for heating and aging, heat at constant temperature for 50 minutes, cool to room temperature, and obtain an extractant; at room temperature, add the extractant to a solution containing mainly Mn at a pH of 3 to 3.5. 2+ ion solution, mixed and stirred for 1.5 hours, allowed to stand for 30 minutes, the upper organic phase was taken, sulfuric acid was added, the pH was adjusted to 1, the manganese extracted by back extraction was transferred to the aqueous phase, and the Mn-containing 2+ The concentration of the first solution is 40g / L; wherein the volume ratio of the extractant to the solution is 1-2:1, and the mass volume ratio of di(2-ethylhexyl) phosphate: sodium hydroxide solid: kerosene is 60ml:6g:150ml.

[0007] Preferably, in step 2, the ammonia water introduced into the cathode chamber is ammonia water at room temperature and with a concentration of 5-10%.

[0008] Preferably, it also includes a vegetable oil film package, the bottom size of which is adapted to the upper surface of the anode chamber. For example, if the upper surface of the anode chamber is square, the bottom size of the vegetable oil film package is correspondingly set to a square to form a cube or a rectangular vegetable oil film package. The vegetable oil film package is filled with vegetable oil and gas, and is used to float on the upper surface of the electrolyte in the anode chamber.

[0009] Preferably, the vegetable oil film bag uses a high temperature resistant soft film bag as an outer packaging, the vegetable oil in the film bag can be peanut oil or soybean oil, etc., when the vegetable oil is evenly spread on the upper surface of the electrolyte, the thickness of the vegetable oil is 0.1~0.5cm, the air pressure in the film bag is equal to the atmospheric pressure, and the volume ratio of the vegetable oil and gas in the film bag is 1:2~5. The material of the high temperature resistant soft film bag can be TPU film, PVC film, etc.

[0010] Preferably, it also includes an ultrasonic oscillator and a magnet or an electromagnet. The magnet is set up outside the electrolytic cell, the south end face of the magnet is close to and facing one end of the diaphragm, the north end face of the magnet is close to and facing the other end of the diaphragm, and the area of ​​the south end face and the north end face of the magnet is 2 to 10 times the corresponding end face of the diaphragm; the ultrasonic vibrator of the ultrasonic oscillator is connected to the bottom of the magnet, and during the electrolysis process, the frequency of starting the ultrasonic vibrator is 20 to 30kHz, which prompts the magnet to oscillate along the height direction of the electrolytic cell. It can not only help reduce the blockage of the diaphragm, but also promote the flow of ion transmission and improve the current efficiency. The ultrasonic oscillator can be started at intervals as needed, such as starting for about 5 minutes at an interval of 2 to 3 hours, and the Lorentz force generated by the temperature difference thermal potential energy between the anode chamber and the cathode chamber and the magnetic field of the oscillating magnet promotes the ion transmission flow force, reduces the blockage of the diaphragm, and is conducive to prolonging the use effect of the diaphragm and improving the current efficiency.

[0011] The present invention has at least the following beneficial effects: 1. The present invention disassembles, sorts and separates waste lithium-ion batteries to obtain the main Mn 2+ ion solution, and then use the extractant to remove Mn 2+ Loaded in the organic phase, and then stripped Mn 2+ In the aqueous phase, it reduces the influence of other metal ions on the purity and electrochemical properties of electrolytic manganese dioxide products.

[0012] 2. The present invention uses a proton exchange membrane as a diaphragm to form ammonia water reaction in the cathode chamber, thereby reducing hydrogen evolution side reactions, improving current efficiency, lowering electrolysis temperature, reducing energy consumption, and improving resource and energy utilization.

[0013] 3. The present invention uses a vegetable oil film package to float on the upper surface of the electrolyte for heat preservation, which is conducive to recycling, and combines a magnet and an ultrasonic oscillator to further improve current efficiency and reduce diaphragm blockage.

[0014] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1A schematic diagram of the structure of a diaphragm electrolytic cell for realizing a production process of electrolytic manganese dioxide of the present invention; Among them, the anode chamber 1; the diaphragm 2; the cathode chamber 3; the south pole of the magnet 4; and the north pole of the magnet 5. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to examples so that those skilled in the art can implement the invention with reference to the description.

[0017] It should be understood that the terms "having", "comprising" and "including" used herein do not exclude the presence or addition of one or more other elements or combinations thereof. It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified. The electrolytic cells used in the production processes of the following examples and comparative examples are of the same material and size, and the corresponding electrode plates are of the same material and size, and the same batch and category of waste lithium-ion batteries are processed.

[0018] Example 1 A production process of electrolytic manganese dioxide, comprising: Step 1: Disassemble and sort the waste lithium-ion batteries, recover the heavy metal elements, and then separate the main Mn 2+ ion solution, sulfuric acid was added to adjust the pH value of the solution to 3.5, and then the extractant was added to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ A first solution of ions; Step 2: add sulfuric acid to the first solution, adjust the concentration of sulfuric acid in the solution to 2 mol / L, and obtain an electrolyte; the electrolysis process occurs in a diaphragm electrolytic cell, the cathode plate and the anode plate are arranged on both sides of the diaphragm, the bottom of the cell on both sides of the diaphragm are provided with a liquid inlet, and the cell wall is provided with a liquid outlet, the electrolyte is introduced into the anode chamber, and the ammonia water is introduced into the cathode chamber; wherein, the anode plate is a titanium-manganese alloy electrode, the cathode plate is a copper plate, and the diaphragm is a proton exchange membrane; the electrolysis process continuously discharges waste liquid and replenishes new liquid, and the anode chamber is passed through a 50°C electrolyte for electrolysis for 3 h, and the anode current density is 60A / m 2 , slot voltage 2V; Step 3: After electrolysis, the mixture is discharged from the tank, crushed, rinsed, ground and dried to obtain electrolytic manganese dioxide.

[0019] Among them, the method for recovering heavy metal elements (such as Pb, Ni, Co and other elements) in step 1 can be selected from the existing acid dissolution method, alkali dissolution method, precipitation method, vibrating screen screening method, flotation separation method or ultrasonic oscillation method.

[0020] The specific method of recycling heavy metal elements in this example is as follows: after discharging the waste lithium-ion battery, disassemble and sort it to obtain a positive electrode material containing lithium cobalt oxide, and then immerse the positive electrode material in an alkaline solution to obtain a black powder with low aluminum content; then dissolve the black powder in dilute sulfuric acid, and then add Fe powder and concentrated sulfuric acid for reduction and dissolution, and the pH value of the solution is controlled at 0.5; finally, use 3 mol / L sulfuric acid for high acid dissolution to completely dissolve the metal elements in the black powder, and then separate the solid and liquid. The obtained solid is acetylene black slag, which is transferred to waste recycling treatment, such as used as a building material raw material. The obtained solution is oxidized and neutralized to deeply remove Al and Fe, and then filtered and washed with clean water. The iron and aluminum slag are used as building materials, and the filtrate and washing liquid are combined into a solution. Chitosan, sodium dimethylaminosulfonate, and sodium chloride are mixed in a mass ratio of 1: 1:0.2 to obtain a composite, and the composite is added to the combined solution. The pH is adjusted to 6 at 20°C and stirred for 15 minutes, and the slag is filtered to obtain a composite containing mainly Mn. 2+ ions in the solution; sulfuric acid was added to adjust the pH value of the solution to 3, and then the extractant was added to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ A first solution of ions; Add the extractant to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ The specific method of the first solution of ions is: Di(2-ethylhexyl) phosphate, sodium hydroxide solid and kerosene were saponified, and then placed in a 60°C constant temperature water bath for heating and aging. After constant temperature heating for 50 minutes, the extractant was cooled to room temperature to obtain an extractant. At room temperature, the extractant was added to a solution containing mainly Mn at a pH of 3.5. 2+ ion solution, mixed and stirred for 1.5 hours, allowed to stand for 30 minutes, the upper organic phase was taken, sulfuric acid was added, the pH was adjusted to 1, the manganese extracted by back extraction was transferred to the aqueous phase, and the Mn-containing 2+ The concentration of the first solution is 40g / L; wherein the volume ratio of the extractant to the solution is 2:1, and the mass volume ratio of di(2-ethylhexyl) phosphate: sodium hydroxide solid: kerosene is 60ml:6g:150ml. The concentration of sulfuric acid added during the test is 3mol / L.

[0021] Among them, in step 2, the ammonia water introduced into the cathode chamber is ammonia water at room temperature and with a concentration of 5%, and the normal temperature of the ammonia water is 25°C.

[0022] Example 2 A production process of electrolytic manganese dioxide, comprising: Step 1: Disassemble and sort the waste lithium-ion batteries, recover the heavy metal elements, and then separate the main Mn 2+ion solution, sulfuric acid was added to adjust the pH value of the solution to 3.5, and then the extractant was added to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ A first solution of ions; Step 2: add sulfuric acid to the first solution, adjust the concentration of sulfuric acid in the solution to 0.2 mol / L, and obtain an electrolyte; the electrolysis process occurs in a diaphragm electrolytic cell, the cathode plate and the anode plate are arranged on both sides of the diaphragm, the bottom of the cell on both sides of the diaphragm are provided with a liquid inlet, and the cell wall is provided with a liquid outlet, the electrolyte is introduced into the anode chamber, and the ammonia water is introduced into the cathode chamber; wherein, the anode plate is a titanium-manganese alloy electrode, the cathode plate is a copper plate, and the diaphragm is a proton exchange membrane; the electrolysis process continuously discharges waste liquid and replenishes new liquid, and the anode chamber is passed through a 40°C electrolyte for electrolysis for 3 h, and the anode current density is 50A / m 2 , cell voltage 1.5V; Step 3: After electrolysis, the mixture is discharged from the tank, crushed, rinsed, ground and dried to obtain electrolytic manganese dioxide.

[0023] Among them, in step 1, the method for recovering heavy metal elements is specifically as follows: after discharging the waste lithium-ion battery, dismantle and sort it to obtain a positive electrode material containing lithium cobalt oxide, and then immerse the positive electrode material in an alkaline solution to obtain a black powder with low aluminum content; then dissolve the black powder in dilute sulfuric acid, and then add Fe powder and concentrated sulfuric acid for reduction dissolution, and the pH value of the solution is controlled at 2.0; finally, use 3 mol / L sulfuric acid for high acid dissolution to completely dissolve the metal elements in the black powder, and then separate the solid and liquid. The obtained solid is acetylene black slag, which is transferred to waste recycling treatment, such as used as a building material raw material. The obtained solution is oxidized and neutralized to remove Al and Fe in depth, and then filtered and washed with clean water. The iron and aluminum slag are used as building materials, and the filtrate and washing liquid are combined into a solution. Chitosan, sodium dimethylaminosulfonate, and sodium chloride are mixed in a mass ratio of 1: 1:0.2 to obtain a composite, and the composite is added to the combined solution. The pH is adjusted to 7 at 25°C and stirred for 15 minutes, and the slag is filtered to obtain a composite containing mainly Mn. 2+ ion solution; sulfuric acid was added to adjust the solution pH to 3.5, and then the extractant was added to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ A first solution of ions; Add the extractant to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ The specific method of the first solution of ions is: Take di(2-ethylhexyl) phosphate, sodium hydroxide solid and kerosene for saponification, then place in a 60℃ constant temperature water bath for heating and aging, heat at constant temperature for 50 minutes, cool to room temperature, and obtain an extractant; at room temperature, add the extractant to a solution containing mainly Mn at a pH of 3 to 3.5.2+ ion solution, mixed and stirred for 1.5 hours, allowed to stand for 30 minutes, the upper organic phase was taken, sulfuric acid was added, the pH was adjusted to 1, the manganese extracted by back extraction was transferred to the aqueous phase, and the Mn-containing 2+ The concentration of the first solution is 40g / L; wherein the volume ratio of the extractant to the solution is 1:1, and the mass volume ratio of di(2-ethylhexyl) phosphate: sodium hydroxide solid: kerosene is 60ml:6g:150ml. The concentration of sulfuric acid added during the test is 3mol / L.

[0024] Among them, in step 2, the ammonia water introduced into the cathode chamber is ammonia water at room temperature and with a concentration of 10%, and the normal temperature of the ammonia water is 20°C.

[0025] Example 3 A production process of electrolytic manganese dioxide is the same as that of Example 2, except that in step 2, the electrolysis process further includes a vegetable oil film bag, and the bottom size of the vegetable oil film bag is adapted to the upper surface of the anode chamber, such as Figure 1 The upper surface of the anode chamber is square, and the bottom size of the vegetable oil film bag is correspondingly set to a square, forming a cube or rectangular vegetable oil film bag, which is filled with vegetable oil and gas, and is used to float on the upper surface of the electrolyte in the anode chamber. The vegetable oil film bag uses a high-temperature resistant and soft film bag as an outer packaging. The vegetable oil filled in the film bag is peanut oil. When the vegetable oil is flatly spread on the upper surface of the electrolyte, the thickness of the vegetable oil is 0.3 cm, the air pressure in the film bag is equal to the atmospheric pressure, and the volume ratio of the vegetable oil and gas in the film bag is 1:4. The material of the high-temperature resistant and soft film bag is TPU film.

[0026] Example 4 A production process of electrolytic manganese dioxide is the same as that of Example 3, except that in step 2, the electrolysis process also includes an ultrasonic oscillator and a magnet or an electromagnet, such as Figure 1As shown in the diagram, the diaphragm 2 in the diaphragm electrolyzer separates the electrolyzer into an anode chamber 1 and a cathode chamber 3, the anode plate is placed in the anode chamber 1, and the cathode plate is placed in the cathode chamber 3, and the anode plate and the cathode plate are not shown in the diagram. The magnet is set up outside the electrolyzer, the south pole 4 end face of the magnet is close to and facing one end of the diaphragm 2, and the north pole 5 end face of the magnet is close to and facing the other end of the diaphragm 2, and the area of ​​the south pole end face and the north pole end face of the magnet is 2 to 10 times the corresponding end face of the diaphragm 2; the ultrasonic vibrator of the ultrasonic oscillator is connected to the bottom of the magnet, and during the electrolysis process, the frequency of starting the ultrasonic vibrator is 20 to 30 kHz, which prompts the magnet to oscillate along the height direction of the electrolyzer; wherein the magnetic induction intensity of the magnet is 1 tesla. This design can not only help reduce the blockage of the diaphragm 2, but also promote the flow of ion transmission and improve the current efficiency. The ultrasonic oscillator can be started at intervals as needed, for example, at intervals of about 5 minutes every 2 to 3 hours, and the Lorentz force generated by the temperature difference thermal potential energy between the anode chamber 1 and the cathode chamber 3 and the magnetic field of the oscillating magnet can promote the ion transmission flow force and reduce the blockage of the diaphragm 2, which is beneficial to prolong the use effect of the diaphragm 2 and improve the current efficiency.

[0027] Example 5 A production process for electrolytic manganese dioxide is the same as that in Example 2, and in step 2, the electrolysis process does not include a vegetable oil film package. Unlike Example 2, the electrolysis process also includes an ultrasonic oscillator and a magnet or an electromagnet. The magnet is set up outside the electrolytic cell, the south end surface of the magnet is close to and faces one end of the diaphragm, and the north end surface of the magnet is close to and faces the other end of the diaphragm. The areas of the south end surface and the north end surface of the magnet are 2 to 10 times the corresponding end surfaces of the diaphragm; the ultrasonic vibrator of the ultrasonic oscillator is connected to the bottom of the magnet. During the electrolysis process, the frequency of starting the ultrasonic vibrator is 20 to 30 kHz, which causes the magnet to oscillate along the height direction of the electrolytic cell; wherein the magnetic induction intensity of the magnet is 1 Tesla.

[0028] The same effect can be achieved by using an electromagnet with the same design as a magnet.

[0029] Comparative Example 1 A production process of electrolytic manganese dioxide is the same as that of Example 2, except that in step 1, the method for recovering heavy metal elements is different. Step 1 of Comparative Example 1 is specifically as follows: The method for recovering heavy metal elements is as follows: after discharging the waste lithium-ion battery, disassembling and sorting it to obtain a positive electrode material containing lithium cobalt oxide, then immersing the positive electrode material in an alkaline solution to obtain a black powder with a low aluminum content; then dissolving the black powder in dilute sulfuric acid, adding Fe powder and concentrated sulfuric acid for reduction dissolution, and controlling the pH value of the solution at 2.0; finally, using 3 mol / L sulfuric acid for high-acid dissolution to completely dissolve the metal elements in the black powder, and then separating the solid and the liquid, the obtained solid is acetylene black slag, which is transferred to waste recycling treatment, such as being used as a building material raw material, and the obtained solution is oxidized and neutralized to deeply remove Al and Fe, and then filtered and washed with clean water, the iron and aluminum slag is used as a building material, and the filtrate and the washing liquid are combined into a solution; sulfuric acid is added to adjust the pH value of the combined solution to 3.5, and then an extractant is added to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ A first solution of ions; Add the extractant to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ The specific method of the first solution of ions is: Take di(2-ethylhexyl) phosphate, sodium hydroxide solid and kerosene for saponification, then place in a 60℃ constant temperature water bath for heating and aging, heat at constant temperature for 50 minutes, cool to room temperature, and obtain an extractant; at room temperature, add the extractant to a solution containing mainly Mn at a pH of 3 to 3.5. 2+ ion solution, mixed and stirred for 1.5 hours, allowed to stand for 30 minutes, the upper organic phase was taken, sulfuric acid was added, the pH was adjusted to 1, the manganese extracted by back extraction was transferred to the aqueous phase, and the Mn-containing 2+ The concentration of the first solution is 40g / L; wherein the volume ratio of the extractant to the solution is 1:1, and the mass volume ratio of di(2-ethylhexyl) phosphate: sodium hydroxide solid: kerosene is 60ml:6g:150ml. The concentration of sulfuric acid added during the test is 3mol / L.

[0030] Comparative Example 2 A production process of electrolytic manganese dioxide is the same as that of Example 2, except that in step 1, an extractant is not added to the solution to extract Mn 2+ ions, and then back-extracted. Step 1 of Comparative Example 2 is specifically as follows: The method for recovering heavy metal elements is as follows: after discharging the waste lithium-ion battery, disassemble and sort it to obtain a positive electrode material containing lithium cobalt oxide, and then immerse the positive electrode material in an alkaline solution to obtain a black powder with low aluminum content; then dissolve the black powder in dilute sulfuric acid, and then add Fe powder and concentrated sulfuric acid for reduction and dissolution, and the pH value of the solution is controlled at 2.0; finally, use 3 mol / L sulfuric acid for high acid dissolution to completely dissolve the metal elements in the black powder, and then separate the solid and liquid. The obtained solid is acetylene black slag, which is transferred to waste recycling treatment, such as used as a building material raw material. The obtained solution is oxidized and neutralized to remove Al and Fe in depth, and then filtered and washed with clean water. The iron and aluminum slag are used as building materials, and the filtrate and washing liquid are combined into a solution. Chitosan, sodium dimethylaminosulfonate, and sodium chloride are mixed in a mass ratio of 1: 1:0.2 to obtain a composite, and the composite is added to the combined solution. The pH is adjusted to 7 at 25°C and stirred for 15 minutes, and the slag is filtered to obtain a composite containing mainly Mn. 2+ ion solution; adding sulfuric acid to adjust the pH value of the solution to 3.5 to obtain a first solution.

[0031] Comparative Example 3 A production process of electrolytic manganese dioxide is the same as that of Example 2, except that in step 2, the ammonia water introduced into the cathode chamber is replaced by an electrolyte.

[0032] According to the detection method of industry standard QB / T2629-2021, the Pb, Ni, Co, and Cu contents (ug / g) of the electrolytic manganese dioxide products prepared by the production processes of Examples 2 to 5 and Comparative Examples 1 to 2 were tested, as shown in Table 1.

[0033] Table 1 The current efficiency index was calculated for the electrolysis process in step 2 of Examples 2 to 5 and Comparative Example 3. The calculation formula of the current efficiency ζ (%) is: ,in, m is the mass of manganese dioxide deposited at the anode (g), q is the electrochemical equivalent, i is the current density (A / m 2 ), t is the electrolysis time (h), and the results are shown in Table 2.

[0034] Table 2 From the data in Table 1 and Table 2, we can see that: Comparative Example 1 does not include the recovery of the composite to remove heavy metal ions, and the purity of the electrolytic manganese dioxide product is low, and the content of heavy metals such as Pb, Ni, and Co is relatively high. Comparative Example 2 does not include the extraction of Mn by an extractant, and the electrolytic manganese dioxide product is doped with a high content of metal Cu, which affects the quality of the electrolytic manganese dioxide. The electrolyte is introduced into the anode chamber and the cathode chamber of Comparative Example 3, and the diaphragm lacks the reaction of forming ammonia water in the cathode chamber, which affects the current efficiency. Example 2 uses a proton exchange membrane as a diaphragm, introduces a 40°C electrolyte into the anode chamber, and introduces room temperature ammonia water into the cathode chamber. Compared with Comparative Example 3, the current efficiency of Example 2 is significantly improved. Analysis shows that the reason may be that the hydrogen ions electrolyzed by the anode plate combine with ammonia water through the proton exchange membrane to produce ammonium ions and hydroxide ions. The ammonium ions obtain electrons to form ammonia water in water, and the cyclic reaction reduces the side reaction of hydrogen evolution and improves the current efficiency. Compared with Comparative Examples 1 and 2, the electrolytic manganese dioxide product obtained by electrolysis in Example 2 has a higher purity. The reason is that the chitosan-modified sodium dimethylaminosulfonate macromolecules contain a large number of hydroxyl and amino groups, which have a strong chelating effect on metal ions. After sodium chloride is precipitated, it is precipitated together with the chelate to better recover Pb, Ni, and Co heavy metal ions, and then combined with the extractant to extract Mn and separate the residual Cu to improve the purity of the electrolyte, thereby improving the purity and electrochemical properties of the electrolytic manganese dioxide product. Example 3 is insulated by floating the vegetable oil film package on the upper surface of the electrolyte, which is conducive to the formation of a temperature difference between the electrolyte in the cathode chamber and the ammonia water in the cathode chamber, which is conducive to the use of the temperature difference thermal potential energy, promoting the transmission and flow of hydrogen ions to the cathode chamber, and is conducive to improving the current efficiency. Compared with Example 4, the current efficiency of Example 5 has decreased. It may be analyzed that there is no insulation of the vegetable oil film package, which affects the active flow of ions formed by the temperature difference thermal potential energy, affects the relative motion of hydrogen ions and the magnetic field, reduces the transmission flow force of hydrogen ions between the diaphragms, and affects the current efficiency. Example 4: Under the action of the temperature difference thermal potential energy between the anode chamber and the cathode chamber and the magnetic field of the oscillating magnet, the Lorentz force generated promotes the ion transmission flow force, reduces the blockage of the diaphragm, is beneficial to prolong the use effect of the diaphragm, and further improves the current efficiency.

[0035] The above results show that the present invention uses a vegetable oil film package to float on the upper surface of the electrolyte for heat preservation, which is beneficial to recycling, and combines a magnet and an ultrasonic oscillator to further improve current efficiency and reduce diaphragm blockage, lower the electrolysis temperature, and reduce energy consumption. It has guiding significance for improving the efficiency of large-scale industrial production and the recycling of waste lithium-ion batteries.

[0036] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. They can be applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized.

Claims

1. A production process for electrolytic manganese dioxide, characterized in that: include: Step 1: Disassemble and sort the waste lithium-ion batteries, recover the heavy metal elements, and then separate the main Mn 2+ ion solution, add sulfuric acid to adjust the solution pH to 3~3.5, and then add the extractant to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ A first solution of ions; Step 2: adding sulfuric acid to the first solution to adjust the concentration of sulfuric acid in the solution to 0.2-2 mol / L to obtain an electrolyte; The electrolysis process takes place in a diaphragm electrolytic cell, wherein the cathode plate and the anode plate are arranged on both sides of the diaphragm, the bottom of the cell on both sides of the diaphragm are provided with a liquid inlet, and the cell wall is provided with a liquid outlet, the electrolyte is introduced into the anode chamber, and the ammonia water is introduced into the cathode chamber; wherein the anode plate is a titanium-manganese alloy electrode, the cathode plate is a copper plate, and the diaphragm is a proton exchange membrane; during the electrolysis process, waste liquid is continuously discharged and new liquid is replenished, the electrolyte at 40-50°C is introduced into the anode chamber for electrolysis, and the anode current density is 50-60A / m 2 , cell voltage 1.5~2V; Step 3: After electrolysis, the mixture is discharged from the tank, crushed, rinsed, ground and dried to obtain electrolytic manganese dioxide.

2. The production process of electrolytic manganese dioxide according to claim 1, characterized in that: In the step 1, an extractant is added to the solution to extract Mn 2+ ions, and then stripped to obtain Mn 2+ The specific method of the first solution of ions is: Take di(2-ethylhexyl) phosphate, sodium hydroxide solid and kerosene for saponification, then place in a 60℃ constant temperature water bath for heating and aging, heat at constant temperature for 50 minutes, cool to room temperature, and obtain an extractant; at room temperature, add the extractant to a solution containing mainly Mn at a pH of 3 to 3.

5. 2+ ion solution, mixed and stirred for 1.5 hours, allowed to stand for 30 minutes, the upper organic phase was taken, sulfuric acid was added, the pH was adjusted to 1, the manganese extracted by back extraction was transferred to the aqueous phase, and the Mn-containing 2+ The concentration of the first solution is 40g / L; wherein the volume ratio of the extractant to the solution is 1-2:1, and the mass volume ratio of di(2-ethylhexyl) phosphate: sodium hydroxide solid: kerosene is 60ml:6g:150ml.

3. The production process of electrolytic manganese dioxide according to claim 1 or 2, characterized in that: In the step 2, the ammonia water introduced into the cathode chamber is ammonia water at room temperature and with a concentration of 5-10%.

4. The production process of electrolytic manganese dioxide as claimed in claim 3, characterized in that: It also includes a vegetable oil film bag, the bottom size of which is adapted to the upper surface of the anode chamber, the vegetable oil film bag is filled with vegetable oil and gas, and the vegetable oil film bag is used to float on the upper surface of the electrolyte in the anode chamber.

5. The production process of electrolytic manganese dioxide according to claim 4, characterized in that: The vegetable oil film bag uses a high-temperature resistant and soft film bag as an outer packaging. When the vegetable oil in the film bag is spread flat on the upper surface of the electrolyte, the thickness of the vegetable oil is 0.1-0.5 cm, the air pressure in the film bag is equal to the atmospheric pressure, and the volume ratio of the vegetable oil and gas in the film bag is 1:2-5.

6. The production process of electrolytic manganese dioxide according to claim 5, characterized in that: It also includes an ultrasonic oscillator and a magnet or an electromagnet. The magnet is set up outside the electrolytic cell, the south end surface of the magnet is close to and faces one end of the diaphragm, and the north end surface of the magnet is close to and faces the other end of the diaphragm. The areas of the south end surface and the north end surface of the magnet are 2 to 10 times the corresponding end surfaces of the diaphragm. The ultrasonic vibrator of the ultrasonic oscillator is connected to the bottom of the magnet. During the electrolysis process, the frequency of starting the ultrasonic vibrator is 20 to 30 kHz, which prompts the magnet to oscillate along the height direction of the electrolytic cell.

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