Process for the simultaneous production of lead and manganese dioxide by solid phase electrolysis in the same bath

Abstract

The application discloses a method for co-production of lead and manganese dioxide by solid-phase electrolysis in the same tank, and relates to the technical field of solid-phase electrolysis. The method uses lead-containing solid waste as a solid-phase cathode, uses a manganese-containing precursor as a solid-phase anode, uses a sodium sulfate aqueous solution with an initial pH of 6-8 and a concentration of 10 g / L-400 g / L as an electrolyte in the same electrolysis tank, electrolyzes at 20-95 DEG C, controls the anode current density to be 10-1000 A / m 2 ~1000A / m 2 , and controls the cathode current density to be twice the anode current density; after electrolysis, the stripping product is obtained, and the lead and the manganese dioxide energy storage material with high added value, high specific capacitance and controllable morphology meet the standard requirements of YS / T 71-2013 crude lead Pb96.0C; and the electrolyte is recycled after pH adjustment to 6-8 to ensure continuous production. Compared with the traditional hydrometallurgy, the total energy consumption of the method for co-production of lead and manganese dioxide per ton is reduced by 70.3%, and the production efficiency is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-phase electrolysis, in particular to a method for co-production of metallic lead and manganese dioxide by solid-phase electrolysis in the same tank. BACKGROUND

[0002] Achieving clean production and energy saving and carbon reduction is the core goal of the industrial society and China's "double carbon" strategy. Therefore, developing a technology that can save energy and reduce emissions, efficiently couple solid waste treatment, and scale production of high-value manganese dioxide (MnO2) energy storage materials has become a key research direction in this field. MnO2, as a high-valent stable oxide of manganese, has high added value due to its important application in battery energy storage. At the same time, if heavy metal lead in lead-containing solid waste is not properly disposed of, it will pose a serious threat to the environment and human health, and an effective method for recovering metallic lead needs to be developed.

[0003] Currently, industrial production of MnO2 mainly uses the electrolytic hot manganese sulfate method, which works on the principle that MnO2 is deposited on the anode, and hydrogen evolution occurs on the cathode. The hydrometallurgical process for treating lead-containing solid waste generally uses the "reduction leaching-electrodeposition" method, which obtains metallic lead by electrodeposition on the cathode, and oxygen evolution occurs on the anode. It can be seen that both of these existing processes only obtain the target product at a single electrode (anode in the former and cathode in the latter), and the energy consumption of the other electrode is wasted in gas evolution reactions, resulting in significant energy waste. Specifically, the energy consumption for producing MnO2 by electrolysis alone is as high as 2500kWh / t~3000kWh / t, and the energy consumption for producing metallic lead by electrodeposition alone is also as high as 500kWh / t~900kWh / t. SUMMARY

[0004] The present application addresses the shortcomings of the prior art by coupling the solid-phase electrolysis of MnO2 and metallic lead processes, developing a method for solid-phase electrolysis to recover metallic lead on the cathode simultaneously, and directly converting high-value MnO2 products on the anode, significantly reducing energy consumption and improving resource utilization efficiency. This has important theoretical and practical significance for promoting energy saving and consumption reduction, quality improvement and efficiency enhancement in related hydrometallurgical processes.

[0005] To this end, the present application provides a method for co-production of metallic lead and manganese dioxide by solid-phase electrolysis in the same tank, comprising the following steps:

[0006] Electrode preparation: mix lead-containing solid waste with deionized water to form a paste, coat it on the cathode plate and wrap it in a bag to make a solid-phase cathode; mix manganese oxide precursors with deionized water to form a paste, coat it on the anode plate and wrap it in a bag to make a solid-phase anode;

[0007] The same tank electrolysis: the solid phase cathode and the solid phase anode are placed in the same electrolysis tank, and the initial pH is 6-8, the concentration of the sodium sulfate aqueous solution is 10 g / L-400 g / L, and the electrolysis is carried out at 20℃-95℃, and the anode current density in the electrolysis process is controlled to be 10 A / m 2 ~1000A / m 2 , and the cathode current density is 2 times of the anode current density.

[0008] Product processing: after the electrolysis is completed, the cathode product is stripped, cleaned and dried to obtain the metal lead, and the anode product is stripped, cleaned and dried to obtain the manganese dioxide;

[0009] Electrolyte circulation: after each electrolysis, the pH of the electrolyte is adjusted to 6-8 for recycling.

[0010] Further, the lead-containing solid waste includes at least one of waste lead paste, lead-containing tailings and lead-containing tailings; and the manganese oxide precursor includes at least one of manganese minerals, a manganese-containing solid oxide obtained by reacting a divalent manganese ion aqueous solution with sodium hydroxide.

[0011] Further, in the same tank electrolysis step, the initial pH of the sodium sulfate aqueous solution is 6.2-7.2, and the concentration is 100 g / L-300 g / L.

[0012] Further, in the same tank electrolysis step, the electrolysis temperature is 25℃-40℃ or 60℃-90℃.

[0013] Further, in the same tank electrolysis step, the anode current density in the electrolysis process is controlled to be 50 A / m 2 ~200A / m 2 .

[0014] Further, in the same tank electrolysis step, the initial pH of the sodium sulfate aqueous solution is 6.7±0.2, the concentration is 180 g / L-220 g / L, the electrolysis temperature is 28℃-32℃ or 78℃-82℃, and the anode current density in the electrolysis process is controlled to be 90 A / m 2 ~110A / m 2 .

[0015] Further, when the electrolysis temperature is 28℃-32℃: the product manganese dioxide is nanospherical structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1400 kWh-1500 kWh, and the specific capacitance is 80 F / g-90 F / g; the chemical composition mass fraction of the product metal lead satisfies: Pb content≥96.0%, Sb content≤0.9%, As content≤0.7%, and the energy consumption per ton of metal lead is 950 kWh-1000 kWh.

[0016] Further, when the electrolysis temperature is 78-82 DEG C, the product manganese dioxide is in nanorod structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1000-1100 kWh, and the specific capacitance is 60-70 F / g; the chemical composition of the product lead meets the requirements of Pb content being not less than 96.0%, Sb content being not more than 0.9%, and As content being not more than 0.7%, and the energy consumption per ton of lead is 700-750 kWh.

[0017] Further, in the same-tank electrolysis step, the initial pH is 6.7±0.2, the concentration of the sodium sulfate aqueous solution is 180-220 g / L, the electrolysis temperature is 78-82 DEG C, the anode current density is 90-110 A / m 2 2 , and the total energy consumption per ton of co-produced lead and manganese dioxide is less than 500 kWh.

[0018] Further, the electrolyte circulation further comprises:

[0019] After each 5 electrolysis cycles, the electrolyte is subjected to manganese removal, sodium hydroxide is added to the electrolyte to adjust the pH value to 7.5±0.2, so that the manganese ions in the electrolyte are precipitated in the form of trimanganese tetroxide, the trimanganese tetroxide is returned to the electrode preparation step as a manganese raw material for preparing the anode paste, and the electrolyte after manganese removal is recycled for the next electrolysis.

[0020] Further, the electrolysis time is 3-6 h.

[0021] Compared with the prior art, the present application has at least the following beneficial effects:

[0022] The method for co-producing lead and manganese dioxide by the same-tank solid-phase electrolysis provided by the present application can produce high-value-added, high-specific-capacitance and morphology-controllable manganese dioxide energy storage materials at the anode while producing lead meeting the requirements of YS / T 71-2013 crude lead Pb96.0C standard at the cathode, and the total energy consumption per ton of co-produced lead and manganese dioxide is reduced by 70.3% compared with the traditional hydrometallurgical process, and the production efficiency is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0024] Figure 1 ​XRD patterns of the co-tank solid-phase electrolysis co-production of metal lead and manganese dioxide provided by the embodiment of the present application; wherein, Figure 1 a is the XRD pattern of the co-tank electrolysis anode manganese dioxide product at different electrolysis temperatures, Figure 1 b is the XRD pattern of the co-tank electrolysis cathode metal lead product at different electrolysis temperatures.

[0025] Figure 2a SEM morphology of the anode manganese dioxide product prepared by the co-tank electrolysis at 80 DEG C provided by the embodiment 1 of the present application.

[0026] Figure 2b SEM morphology of the cathode metal lead product prepared by the co-tank electrolysis at 80 DEG C provided by the embodiment 1 of the present application.

[0027] Figure 3a SEM morphology of the anode manganese dioxide product prepared by the co-tank electrolysis at 30 DEG C provided by the embodiment 2 of the present application.

[0028] Figure 3b SEM morphology of the cathode metal lead product prepared by the co-tank electrolysis at 30 DEG C provided by the embodiment 2 of the present application.

[0029] Figure 4 Cyclic voltammetry curve of the manganese dioxide product prepared by the co-tank electrolysis anode at 80 DEG C provided by the embodiment 1 of the present application at different scan speeds.

[0030] Figure 5 Charge-discharge curve of the manganese dioxide product prepared by the co-tank electrolysis anode at 80 DEG C provided by the embodiment 1 of the present application at different current densities.

[0031] Figure 6 Electrochemical impedance spectrum of the manganese dioxide product prepared by the co-tank electrolysis anode at 80 DEG C provided by the embodiment 1 of the present application.

[0032] Figure 7 Cyclic voltammetry curve of the manganese dioxide product prepared by the co-tank electrolysis anode at 30 DEG C provided by the embodiment 2 of the present application at different scan speeds.

[0033] Figure 8 Charge-discharge curve of the manganese dioxide product prepared by the co-tank electrolysis anode at 30 DEG C provided by the embodiment 2 of the present application at different current densities.

[0034] Figure 9 Electrochemical impedance spectrum of the manganese dioxide product prepared by the co-tank electrolysis anode at 30 DEG C provided by the embodiment 2 of the present application.

[0035] Figure 10The cycle stability test curve of the supercapacitor device made of the nanospherical manganese dioxide product prepared by the same-tank electrolysis anode at 30 DEG C for the embodiment 2 of the present application.

[0036] Figure 11a The SEM morphology of the manganese dioxide product prepared by the single solid phase electrolysis at 80 DEG C for the comparative example 3 of the present application.

[0037] Figure 11b The SEM morphology of the manganese dioxide product prepared by the single solid phase electrolysis at 30 DEG C for the comparative example 4 of the present application. DETAILED DESCRIPTION

[0038] In order to better understand the above technical solutions, the technical solutions of the embodiments of the present application are described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments and the specific features in the examples are detailed descriptions of the technical solutions of the embodiments of the present application, and are not limitations of the technical solutions of the present application. In the case of no conflict, the technical features in the embodiments and the examples can be combined with each other.

[0039] The embodiment of the present application provides a method for co-production of metal lead and manganese dioxide by same-tank solid phase electrolysis, comprising the following steps:

[0040] Preparation of electrode: the lead-containing solid waste is mixed with deionized water to form a paste, which is coated on a cathode plate and wrapped to form a solid phase cathode; the manganese oxide precursor is mixed with deionized water to form a paste, which is coated on an anode plate and wrapped to form a solid phase anode;

[0041] Same-tank electrolysis: the solid phase cathode and the solid phase anode are placed in the same electrolysis tank, and the electrolysis is carried out at 20 DEG C ~ 95 DEG C with an initial pH of 6 ~ 8 and a concentration of 10 g / L ~ 400 g / L of sodium sulfate aqueous solution as electrolyte, and the anode current density is controlled to be 10 A / m 2 ~ 1000 A / m 2 , and the cathode current density is 2 times of the anode current density;

[0042] Product treatment: after the electrolysis is completed, the cathode product is peeled off, washed and dried to obtain metal lead, and the anode product is peeled off, washed and dried to obtain manganese dioxide;

[0043] Electrolyte circulation: in order to ensure the electrolysis effect of continuous production, the pH of the electrolyte is adjusted to 6 ~ 8 after each electrolysis and recycled.

[0044] It can be understood that in the prior art, the recovery of lead from lead-containing solid waste and the preparation of manganese dioxide by electrolysis are completed by two independent electrolysis processes. In these two processes, the target product (metal lead or manganese dioxide) is only generated at a single electrode (cathode or anode), and the other electrode undergoes a gas evolution reaction (hydrogen evolution or oxygen evolution), resulting in about half of the electrical energy being wasted instead of being used for product generation. Therefore, the treatment of lead-containing solid waste and the preparation of manganese dioxide by the prior art have the problems of high energy consumption and high cost, and the acidic or alkaline electrolyte brought by the gas evolution reaction also causes harm to operators and equipment.

[0045] The method for co-production of metal lead and manganese dioxide in the same tank provided by the embodiments of the present application can produce metal lead meeting the requirements of the crude lead Pb96.0C standard of YS / T 71-2013 at the cathode while simultaneously producing high-value-added, high-specific-capacitance and morphology-controllable manganese dioxide energy storage materials at the anode. Compared with the traditional hydrometallurgical process, the total energy consumption of the method for co-production of metal lead and manganese dioxide per ton is reduced by 70.3%, and the production efficiency is significantly improved.

[0046] In some embodiments, the lead-containing solid waste includes at least one of waste lead paste, lead-containing tailings and lead-containing tailings; and the manganese oxide precursor includes at least one of manganese minerals, a manganese-containing solid oxide obtained by reacting a divalent manganese ion aqueous solution with sodium hydroxide.

[0047] Specifically, the lead-containing solid waste includes but is not limited to waste lead paste, lead-containing tailings and lead-containing tailings (such as galena PbS, cerussite, etc.), and the lead-containing solid waste as the cathode raw material can not only safely dispose of high-risk solid waste on a large scale and reduce environmental risks, but also efficiently recover valuable metal lead resources. The manganese oxide precursor is selected from low-valence manganese minerals (such as manganosite MnOOH, hausmannite MnO, rhodochrosite MnCO3) or is prepared by a simple precipitation method (a divalent manganese ion aqueous solution reacts with sodium hydroxide to generate a manganese-containing solid oxide precipitate, such as Mn3O4, Mn2O3 and Mn(OH)2, etc.).

[0048] In the same-tank electrolysis step, the electrolysis temperature is preferably 25°C to 40°C or 60°C to 90°C, more preferably the electrolysis temperature is 28°C to 32°C or 78°C to 82°C, further, the energy consumption is the lowest, and more preferably the electrolysis temperature is 80°C, at which the manganese dioxide product has a nanorod morphology and good electrochemical energy storage performance, and more preferably the electrolysis temperature is 30°C, at which the manganese dioxide product has a nanospherical morphology. Figure 1 The co-production of metal lead and manganese dioxide in the same tank at different temperatures is given as follows: Figure 1 b) manganese dioxide (MnO2) Figure 1The XRD pattern of a) can be seen that in the temperature range investigated, the precursor reaction raw materials can be solid-phase electro-oxidized into γ-type manganese dioxide, and the cathode lead-containing solid waste can be solid-phase electro-reduced into metal lead, and no other impurity peaks are found in the product, indicating excellent electrolysis effect.

[0049] The initial pH of the electrolyte is preferably 6.2-7.2, more preferably 6.7±0.2, and most preferably 6.7. When the initial pH of the electrolyte is less than 6, the cathode current efficiency is reduced, and the specific capacitance of the anode manganese dioxide product is also reduced. When the pH of the electrolyte is greater than 8, the anode current efficiency is reduced, and too high pH may cause the metal lead generated in the cathode to dissolve and contaminate the purity of the anode manganese dioxide product.

[0050] The concentration of the electrolyte is preferably 100g / L-300g / L of a sodium sulfate aqueous solution, more preferably 180g / L-220g / L of a sodium sulfate aqueous solution, and most preferably 200g / L of a sodium sulfate aqueous solution.

[0051] The anode current density in the electrolysis process is preferably 50A / m 2 ~200A / m 2 , more preferably 90A / m 2 ~110A / m 2 , and most preferably 100A / m 2 .

[0052] The process of the embodiment of the application belongs to a kind of electrolysis process, and electrolysis conditions can be conveniently controlled. The electrolysis temperature is controlled by heating equipment and temperature monitoring device, the initial pH of the electrolyte is adjusted by adding H2SO4 or NaOH, and the concentration of the electrolyte is controlled by controlling the amount of added sodium sulfate. In the process of the same tank solid-phase electrolysis, the cathode and anode solid raw materials gain or lose electrons in the cathode and anode under the action of an external electric field, and the original chemical bonds of the cathode and anode solid raw materials are broken. At the same time, the high-valence lead element in the cathode is reduced to metal lead, and the low-valence manganese element in the anode is oxidized to manganese dioxide product, so that solid-phase electrolysis is realized in the cathode and anode to obtain the target product. It is noted that the cathode solid raw material waste lead paste contains a large amount of lead sulfate (mass fraction usually > 50%), which will release sulfate ions into the electrolyte during solid-phase electro-reduction due to the breaking of ionic bonds. At the same time, the anode reaction will continuously produce hydrogen ions, and the combination of sulfate ions and hydrogen ions generates sulfuric acid, which will continuously accumulate sulfuric acid in the electrolysis process and continuously reduce the pH of the electrolyte. These generated sulfuric acid can be neutralized by adding low-cost sodium hydroxide, thereby realizing the regeneration and circulation of the electrolyte.

[0053] In some embodiments, when the electrolysis temperature is 28-32 DEG C: the product manganese dioxide is nanospherical structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1400-1500 kWh, the specific capacitance is 80-90 F / g; the chemical composition mass fraction of the product lead meets: Pb content is greater than or equal to 96.0%, Sb content is less than or equal to 0.9%, As content is less than or equal to 0.7%, the energy consumption per ton of lead is 950-1000 kWh.

[0054] In some embodiments, when the electrolysis temperature is 78-82 DEG C: the product manganese dioxide is nanorod structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1000-1100 kWh, the specific capacitance is 60-70 F / g; the chemical composition mass fraction of the product lead meets: Pb content is greater than or equal to 96.0%, Sb content is less than or equal to 0.9%, As content is less than or equal to 0.7%, the energy consumption per ton of lead is 700-750 kWh.

[0055] In some embodiments, in the same-tank electrolysis step, the initial pH is 6.7±0.2, the concentration of the sodium sulfate aqueous solution is 180-220 g / L, the electrolysis temperature is 78-82 DEG C, the anode current density is 90-110 A / m 2 2 , and the total energy consumption per ton of co-produced lead and manganese dioxide is less than 500 kWh.

[0056] In some embodiments, the electrolyte circulation further comprises: after completing 5 electrolysis cycles, electrolyte manganese removal is performed, sodium hydroxide is added to the electrolyte to adjust the pH value to 7.5±0.2, so that the manganese ions in the electrolyte are precipitated in the form of trimanganese tetroxide, the trimanganese tetroxide is returned to the electrode preparation step as a manganese raw material for preparing the anode paste, and the electrolyte after manganese removal is recycled for electrolysis.

[0057] Specifically, to realize continuous production and ensure electrolysis effect, the pH of the electrolyte after electrolysis needs to be adjusted and the manganese ions in the electrolyte need to be recovered. Sodium hydroxide is used to adjust the pH of the electrolyte and recover the manganese ions. After the same-tank electrolysis, sodium hydroxide is added to the electrolyte (at this time, the pH of the electrolyte is about 4.3) to neutralize the generated sulfuric acid, the pH of the electrolyte is adjusted to about 6.7, and then the electrolysis can continue. After 5 electrolysis cycles, sodium hydroxide is added to adjust the pH of the electrolyte to about 7.5 to recover the manganese ions in the electrolyte. At this time, the manganese ions will precipitate in the form of brownish yellow trimanganese tetroxide and settle at the bottom of the electrolysis tank. After filtration, washing and drying, trimanganese tetroxide precursor can be obtained again to return to the electrolysis process, so as to realize the regeneration and recycling of the electrolyte and the continuous production of the electrolysis process.

[0058] In some embodiments, the time for each electrolysis is 3-6 h. ​

[0059] Specifically, too long electrolysis time will result in continuous increase of electrolyte acidity and manganese ion concentration, reducing cathode current efficiency and electrochemical energy storage performance of anode manganese dioxide product, and too short electrolysis time will result in incomplete solid-phase electrolysis process and incomplete reaction of reactants. Therefore, the final electrolysis time is determined to be 3-6 h.

[0060] Example 1: A method for co-production of metal lead and manganese dioxide by in-situ solid-phase electrolysis

[0061] A method for co-production of metal lead and manganese dioxide by in-situ solid-phase electrolysis, comprising the following steps:

[0062] (1) 1.5 g of manganese oxide-containing solid waste and 2.3 g of lead-containing solid waste are weighed, and 1.2 mL and 1.5 mL of deionized water are added to the above two kinds of solid powders respectively and stirred thoroughly.

[0063] (2) The mixed reaction raw materials are coated on square electrode plates, and the area ratio of anode to cathode plate is 1:2.

[0064] (3) The electrode plates coated with reaction raw material paste are dried at 80°C for 1 hour, then wrapped with square cloth bag material; then, a polytetrafluoroethylene braided rope with a diameter of 1 mm is used to tie firmly to make a bagged electrode.

[0065] (4) Electrolysis is carried out in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7, the anode current density of the electrolysis process is 100 A / m 2 , the cathode current density is 200 A / m 2 , the electrolysis temperature is 80°C, the electrolysis time is 200 min, and the cathode plate of the electrolysis system is a bagged cathode with lead-containing solid waste as solid reaction raw material, and the anode plate is a bagged anode made of manganese oxide as reaction raw material.

[0066] (5) After electrolysis, the cathode electro-reduction product is peeled off using a stainless steel blade, and then rinsed twice with deionized water and anhydrous ethanol respectively. To avoid oxidation of the product to the greatest extent, the metal lead product after rinsing is placed in a vacuum drying oven at 90°C for vacuum drying for 1 hour.

[0067] (6) After electrolysis, the anode electro-oxidation product is peeled off using a glass sheet, washed several times with deionized water, and then the electro-oxidation product is flushed into a centrifuge tube with deionized water, centrifuged at a speed of 6000 r·min -1 for 10 min, and after centrifugation, the supernatant is poured out and dried in an oven at 80°C for 2 hours to obtain dry manganese dioxide product.

[0068] The dry products are weighed, and 1.51 g of metal lead product and 1.03 g of manganese dioxide product are obtained.

[0069] The main technical indicators of the Pb-MnO2 in-tank solid-phase electrolysis process in Example 1 are as follows: the energy consumption per ton of metal lead is 733.7 kWh, the metal lead reaches the YS / T 71-2013 crude lead Pb96.0C standard requirement; the energy consumption per ton of manganese dioxide is 1079.8 kWh, the manganese dioxide yield is 99.60%, and the electrochemical energy storage performance index is 66.8 F / g. The specific capacitance of the commercially available electrolytic manganese dioxide product of the National Medicine Group is only 27.2 F / g, and the energy consumption when the sum of the mass of the manganese dioxide produced by the anode and the metal lead generated by the cathode is one ton (i.e., the energy consumption per ton of combined products) is 448.7 kWh. The energy consumption of the traditional hydrometallurgical process for producing the same mass of products is 1510 kWh, and the energy saving and emission reduction of the present process is about 70.3%.

[0070] The SEM morphology of the manganese dioxide product prepared in Example 1 is shown in Figure 2a , and the SEM morphology of the metal lead product prepared in Example 1 is shown in Figure 2b . As can be seen from Figure 2a , the micro-morphology of the prepared MnO2 product presents a nanorod structure, the length of the nanorod particles is about 30 nm-90 nm, and the diameter is about 5 nm-20 nm, which is obviously different from the MnO2 morphology obtained at 80°C in Figure 11a . As can be seen from Figure 2b , the micro-morphology of the prepared metal lead product presents a relatively dense block structure of sponge lead, and the relatively compact microstructure increases the mechanical strength of the macro metal lead product, which is beneficial to the operation of product collection.

[0071] The cyclic voltammetry curve, charge-discharge curve and electrochemical impedance spectrum of the manganese dioxide product prepared in Example 1 are shown in Figure 4 , Figure 5 and Figure 6 . As can be seen, the area enclosed by the cyclic voltammetry curve of the MnO2 product prepared by in-tank electrolysis increases with the increase of the scanning rate, which reflects that the MnO2 material has good capacitive charge storage characteristics, and the approximately rectangular cyclic voltammetry curve reflects its ideal capacitive behavior. However, the area enclosed by the cyclic voltammetry curve of the manganese dioxide product prepared in Example 1 and the discharge time are small, and the impedance is high, which reflects that the charge transfer and ion diffusion in the electrochemical energy storage process are more difficult.

[0072] Example 2 A method for co-producing metal lead and manganese dioxide by in-tank solid-phase electrolysis

[0073] A method for co-producing metal lead and manganese dioxide by in-tank solid-phase electrolysis, comprising the following steps:

[0074] (1) 1.5 g of manganese oxide-containing solid waste and 2.3 g of lead-containing solid waste were weighed, and 1.2 mL and 1.5 mL of deionized water were added to the two kinds of solid powders respectively and stirred thoroughly.

[0075] (2) The mixed reaction raw materials were coated on square electrode plates, and the area ratio of the anode plate to the cathode plate was 1:2.

[0076] (3) The electrode plates coated with the reaction raw material paste were dried at 80°C for 1 hour, then wrapped with square cloth bag material; then, a polytetrafluoroethylene braided rope with a diameter of 1 mm was used to tie the bagged electrode tightly.

[0077] (4) The electrolysis was carried out in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7, the anode current density was 100 A / m 2 , the cathode current density was 200 A / m 2 , the electrolysis temperature was 30°C, the electrolysis time was 335 min, and the cathode plate of the electrolysis system was a bagged cathode containing lead-containing solid waste as a solid reaction raw material, and the anode plate was a bagged anode made of manganese oxide as a reaction raw material.

[0078] (5) After electrolysis, the cathode electro-reduction product was peeled off using a stainless steel blade, and then rinsed twice with deionized water and anhydrous ethanol respectively. To avoid oxidation of the product to the greatest extent, the lead metal product after rinsing was placed in a vacuum drying oven at 90°C for 1 hour.

[0079] (6) After electrolysis, the anode electro-oxidation product was peeled off using a glass sheet, washed several times with deionized water, and then the electro-oxidation product was flushed into a centrifuge tube with deionized water, centrifuged at a speed of 6000 r·min -1 for 10 min, and the supernatant was poured out after centrifugation and dried in an oven at 80°C for 2 hours to obtain dry manganese dioxide product.

[0080] The dry products were weighed, and 1.45 g of lead metal product and 1.07 g of manganese dioxide product were obtained.

[0081] The main technical indicators of the Pb-MnO2 in-tank solid-phase electrolysis process in Example 2: the energy consumption per ton of lead metal produced was 972.9 kWh, the lead metal reached the YS / T 71-2013 crude lead Pb96.0C standard requirement; the energy consumption per ton of manganese dioxide produced was 1435.8 kWh, the manganese dioxide yield was 99.03%, and the electrochemical energy storage performance index specific capacitance was 84.7 F / g.

[0082] The SEM morphology of the manganese dioxide product prepared in Example 2 is shown in Figure 3a , and the SEM morphology of the lead metal product prepared in Example 1 is shown in Figure 3b . From Figure 3aIt can be seen that the MnO2 product prepared at low temperature of 30℃ presents a nanospherical structure agglomerated together, and the nanosphere size is between 50nm and 150nm, which is much larger than that of the MnO2 nanosphere (10nm~100nm) obtained by the single electro-oxidation at 30℃. Figure 11b It can be seen that the size of the MnO2 nanosphere obtained by the single electro-oxidation at 30℃ is much larger than that of the MnO2 nanosphere (10nm~100nm) obtained by the single electro-oxidation at 30℃. Figure 3b It can be seen that the micro-morphology of the cathode metal lead product prepared at low temperature of 30℃ changes little, and it is still the sponge lead morphology with rough surface.

[0083] The cyclic voltammetry curve, charge-discharge curve and electrochemical impedance spectrum of the MnO2 product prepared in Example 2 are shown in Figure 7 , Figure 8 and Figure 9 It can be seen that the area enclosed by the cyclic voltammetry curve of the MnO2 product prepared by the electrolysis in the same tank increases with the increase of the scanning rate, which reflects that the MnO2 material has good capacitive charge storage characteristics, and the approximately rectangular cyclic voltammetry curve reflects its ideal capacitive behavior. In addition, the area enclosed by the cyclic voltammetry curve and the discharge time of the MnO2 product prepared in Example 2 are both larger than those of the MnO2 product prepared in Example 1, and the overall diffusion impedance and charge transfer impedance are both smaller than those of the MnO2 product prepared in Example 1, which indicates that the capacitive performance of the MnO2 product prepared in Example 2 is better than that of the MnO2 product prepared in Example 1, which reflects the significant influence of temperature on the electrochemical energy storage performance of the MnO2 product prepared by the solid-phase electrolysis in the same tank.

[0084] The cyclic stability test curve of the MnO2 product prepared in Example 2 is shown in Figure 10 It can be seen that the product shows good capacity retention rate and charge-discharge cycle stability. The capacity retention rate after 10000 times of charge-discharge cycle is as high as 97.8%, and the coulombic efficiency is as high as 98%, which further verifies the excellent electrochemical energy storage performance thereof.

[0085] Example 3 A method for co-production of metal lead and manganese dioxide by solid-phase electrolysis in the same tank

[0086] A method for co-production of metal lead and manganese dioxide by solid-phase electrolysis in the same tank, comprising the following steps:

[0087] (1) 1.5g of manganese-containing oxide and 3.8g of lead-containing solid waste are weighed, and 1.2mL and 1.5mL of deionized water are respectively added to the above two kinds of solid powders and fully stirred and mixed.

[0088] (2) The mixed reaction raw materials are coated on square electrode plates, and the area ratio of the anode plate to the cathode plate is 1:2.

[0089] (3) The pole coated with the paste of the reaction raw material is wrapped with a square cloth bag material after drying at 80°C for 1 hour; then, a polytetrafluoroethylene braided rope with a diameter of 1 mm is used to tie firmly to make a bagged electrode.

[0090] (4) The electrolysis is carried out in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7, an anode current density of 200 A / m 2 , a cathode current density of 400 A / m 2 , an electrolysis temperature of 80°C, an electrolysis time of 335 min, and a cathode plate of the electrolysis system being a bagged cathode containing lead-containing solid waste as a solid reaction raw material and an anode plate being a bagged anode made of manganese oxide as a reaction raw material.

[0091] (5) After the electrolysis, the cathode electro-reduction product is stripped using a stainless steel blade, and then is washed twice using deionized water and anhydrous ethanol, respectively. To avoid the product from being oxidized to the greatest extent, the lead product after washing is placed into a vacuum drying oven and vacuum dried at 90°C for 1 hour.

[0092] (6) After the electrolysis, the anode electro-oxidation product is stripped using a glass sheet, and after being washed multiple times using deionized water, the electro-oxidation product is flushed into a centrifuge tube using deionized water, and is centrifuged at a speed of 6000 r·min -1 for 10 min. After the centrifugation, the supernatant is poured out and is dried in an oven at 80°C for 2 hours to obtain a dried manganese dioxide product.

[0093] The dried products are weighed to obtain 2.63 g of the lead product and 0.92 g of the manganese dioxide product.

[0094] The main technical indicators of the Pb-MnO2 in-tank solid-phase electrolysis process in Example 3 are as follows: the energy consumption per ton of produced lead is 849.8 kWh, the lead reaches the YS / T 71-2013 crude lead Pb96.0C standard requirement; the energy consumption per ton of produced manganese dioxide is 2335.3 kWh, the manganese dioxide yield is 93.72%, and the electrochemical energy storage performance index is a specific capacitance of 58.6 F / g.

[0095] Example 1 Influence of initial pH of electrolyte on co-production of lead and manganese dioxide by in-tank solid-phase electrolysis

[0096] During the continuous electrolysis production process, the adjustment of the initial pH of the electrolyte is crucial. The following introduces the in-tank electrolysis effect when the initial pH of the electrolyte is 0.29.

[0097] A method for co-producing lead and manganese dioxide by in-tank solid-phase electrolysis, comprising the following steps:

[0098] (1) 1.5 g of manganese oxide-containing solid waste and 3.8 g of lead-containing solid waste were weighed, and 1.2 mL and 1.5 mL of deionized water were added to the above two kinds of solid powders respectively and stirred thoroughly.

[0099] (2) The mixed reaction raw materials were coated on square electrode plates, and the area ratio of the anode plate to the cathode plate was 1:2.

[0100] (3) The electrode plates coated with the reaction raw material paste were dried at 80°C for 1 hour, then wrapped with square cloth bag material; then, a polytetrafluoroethylene braided rope with a diameter of 1 mm was used to tie the bagged electrode tightly.

[0101] (4) The electrolysis was carried out in a sulfuric acid solution with an initial pH of 0.29 and 200 g / L of sodium sulfate, and the anode current density was 200 A / m 2 , the cathode current density was 400 A / m 2 , the electrolysis temperature was 80°C, the electrolysis time was 335 min, and the cathode plate of the electrolysis system was a bagged cathode containing lead-containing solid waste as a solid reaction raw material, and the anode plate was a bagged anode made of manganese oxide as a reaction raw material.

[0102] (5) After electrolysis, the cathode electro-reduction product was peeled off using a stainless steel blade, and then rinsed twice with deionized water and anhydrous ethanol respectively. To avoid oxidation of the product as much as possible, the rinsed lead product was placed in a vacuum drying oven at 90°C for 1 hour.

[0103] (6) After electrolysis, the anode electro-oxidation product was peeled off using a glass sheet, washed several times with deionized water, and then the electro-oxidation product was flushed into a centrifuge tube with deionized water, and centrifuged at a speed of 6000 r·min -1 for 10 min. After centrifugation, the supernatant was poured out and dried in an oven at 80°C for 2 hours to obtain dry manganese dioxide product.

[0104] The dry product was weighed, and the electro-reduction product was 2.63 g, and the manganese dioxide product was 0.88 g.

[0105] The main technical indicators of the Pb-MnO2 in-situ solid-phase electrolysis process in Comparative Example 1: the energy consumption per ton of metal lead was 896.4 kWh, the desulfurization rate was 85.3%, and the lead recovery rate was 93.8%, which were significantly lower than the electrolysis effect of the neutral electrolyte; the energy consumption per ton of manganese dioxide was 2350.6 kWh, the manganese dioxide yield was 99.7%, and the specific electrochemical energy storage performance index was 60.3 F / g, which were basically the same as the electrolysis effect of the neutral electrolyte.

[0106] By comparing Example 3 and Comparative Example 1, the results show that the anodic electro-oxidation effect in the acidic electrolyte is basically unchanged, but the cathodic electro-reduction effect is sharply decreased, the energy consumption of the lead-containing solid waste electro-reduction is increased by 22.1% compared with the neutral electrolyte, the desulfurization rate is decreased by 14%, and the lead recovery rate is decreased by about 6%. In the same tank electrolysis process, the reduction process of the lead-containing solid waste at the cathode will continuously release sulfate ions, and the anode reaction will release hydrogen ions, so the pH of the same tank electrolysis process will continuously decrease, and therefore, before each electrolysis cycle, sodium hydroxide needs to be used to adjust the pH back to about 6.7 to ensure the best electrolysis effect.

[0107] Example 2 Influence of initial pH of electrolyte on co-production of lead and manganese dioxide by same tank solid-phase electrolysis (II)

[0108] In the continuous electrolysis production process, the adjustment of the initial pH of the electrolyte is critical. The following describes the same tank electrolysis effect when the initial pH of the electrolyte is 11.5.

[0109] (1) 1.5 g of manganese-containing oxides and 3.8 g of lead-containing solid waste were weighed, and 1.2 mL and 1.5 mL of deionized water were added to the above two kinds of solid powders respectively and stirred thoroughly.

[0110] (2) The mixed reaction materials were coated on square electrode plates, and the area ratio of the cathode to the anode was 1:2.

[0111] (3) The electrode plates coated with the reaction material paste were dried at 80°C for 1 hour, then wrapped with square cloth bags, and then tightly bound with polytetrafluoroethylene braided ropes to form bagged electrodes.

[0112] (4) The electrolysis was carried out in a NaOH solution with an initial pH of 11.5 and 200 g / L of sodium sulfate mixed aqueous solution, the anode current density was 200 A / m 2 , the cathode current density was 400 A / m 2 , the electrolysis temperature was 80°C, the electrolysis time was 335 min, and the cathode plate of the electrolysis system was a bagged cathode with lead-containing solid waste as the solid reaction material, and the anode plate was a bagged anode made of manganese oxides as the reaction material.

[0113] (5) After electrolysis, the cathode electro-reduction product was peeled off using a stainless steel blade, and then rinsed twice with deionized water and anhydrous ethanol. To avoid oxidation of the product to the greatest extent, the lead metal product after rinsing was placed in a vacuum drying oven and vacuum dried at 90°C for 1 hour.

[0114] (6) After electrolysis, the anode electro-oxidation product was peeled off using a glass sheet, washed several times with deionized water, and then the electro-oxidation product was flushed into a centrifuge tube with deionized water, and then centrifuged at 6000 r·min -1The centrifugal separation was carried out at 6000r / min for 10 minutes, and the supernatant was poured out and dried in an oven at 80℃ for 2 hours to obtain the dried manganese dioxide product.

[0115] The dried product was weighed, and 2.72g of the electro-reduction product and 0.56g of the manganese dioxide product were obtained.

[0116] The main technical indicators of the Pb-MnO2 solid-phase electrolysis process in Comparative Example 2 were as follows: the energy consumption per ton of metal lead was 623.4kWh, the desulfurization rate was 99.6%, and the lead recovery rate was 98.8%, which were basically the same as the electrolysis effect of the neutral electrolyte; the energy consumption per ton of manganese dioxide was 4426.7kWh, and the specific electrochemical energy storage performance index was 59.6F / g, which were significantly lower than the electrolysis effect of the neutral electrolyte.

[0117] Through the comparison between Comparative Example 2 and Example 3, it was found that the cathode electro-reduction effect in the alkaline electrolyte was basically unchanged, but the solid-phase electro-oxidation effect of the anode manganese-containing oxide was greatly reduced, the energy consumption of the anode electro-oxidation was about 3 times higher than that of the neutral electrolyte, and the manganese recovery rate decreased by about 53%. Therefore, the pH of the electrolyte in the electrolysis process should not be too high, and sodium hydroxide should be used to adjust the pH back to about 6.7 before each electrolysis cycle to ensure the best electrolysis effect.

[0118] Comparative Example 3: A method for preparing manganese dioxide by separate solid-phase electro-oxidation

[0119] A method for preparing manganese dioxide by separate solid-phase electro-oxidation, comprising the following steps:

[0120] (1) 1.5g of manganese-containing oxide was weighed and added to 1.8mL of deionized water and stirred thoroughly.

[0121] (2) The mixed reaction raw materials were coated on a square electrode plate.

[0122] (3) The electrode plate coated with the reaction raw material paste was dried at 80℃ for 1 hour, then wrapped with square cloth bag material, and then tied firmly with a 1mm diameter polytetrafluoroethylene braided rope to form a bagged electrode.

[0123] (4) Electrolysis was carried out in a 200g / L sodium sulfate aqueous solution with an initial pH of 6.7, the current density of the electrolysis process was 100A / m 2 , the electrolysis temperature was 80℃, the electrolysis time was 5h, the cathode plate of the electrolysis system was stainless steel, and the anode plate was a bagged anode made of manganese oxide as the reaction raw material.

[0124] (5) After electrolysis, the anode electro-oxidation product was peeled off using a glass sheet, washed several times with deionized water, and then washed into a centrifuge tube with deionized water, and centrifuged at 6000r / min -1Centrifuge at a speed of 10 min for 10 min, then discard the supernatant and dry in an oven at 80℃ for 2 hours to obtain dried manganese dioxide product.

[0125] The main technical indicators of the standalone electro-oxidation electrolysis process in Comparative Example 3 are: energy consumption per ton of manganese dioxide produced is 1807.57 kWh, manganese dioxide yield is 97.60%, and specific capacitance is 68.9 F / g.

[0126] The SEM morphology of the manganese dioxide product prepared in Comparative Example 3 is as follows: Figure 11a As shown.

[0127] Comparative Example 4: A method for preparing manganese dioxide by solid-phase electrooxidation alone.

[0128] A method for preparing manganese dioxide by solid-phase electro-oxidation alone includes the following steps:

[0129] (1) Weigh 1.5g of manganese oxide precursor, add 1.8mL of deionized water and stir thoroughly.

[0130] (2) The mixed reaction materials are coated on a square electrode plate.

[0131] (3) After the electrode plate coated with the reaction raw material paste is dried at 80°C for 1 hour, it is wrapped with square cloth bag material; then, it is tied firmly with polytetrafluoroethylene braided rope with a diameter of 1 mm to form a bagged electrode.

[0132] (4) Electrolysis was carried out in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7 at a current density of 100 A / m. 2 The electrolysis temperature is 30℃, the electrolysis time is 3h, the cathode plate of the electrolysis system is stainless steel, and the anode plate is a bagged anode made of manganese oxide as the reaction raw material.

[0133] (5) After electrolysis, the anodic electro-oxidation products are removed using a glass slide, washed multiple times with deionized water, and then rinsed into centrifuge tubes with deionized water. The centrifuge tubes are then heated at 6000 r·min. -1 Centrifuge at a speed of 10 min for 10 min, then discard the supernatant and dry in an oven at 80℃ for 2 hours to obtain dried manganese dioxide product.

[0134] The main technical indicators of the standalone electro-oxidation electrolysis process in Comparative Example 4 are: energy consumption of 2448.6 kWh per ton of manganese dioxide, manganese dioxide yield of 85.7%, and specific capacitance of 162.1 F / g for electrochemical energy storage performance.

[0135] The SEM morphology of the manganese dioxide product prepared in Comparative Example 4 is as follows: Figure 11b As shown.

[0136] From the comparison of Comparative Example 3 and Example 1, and the comparison of Comparative Example 4 and Example 2, it can be seen that: 1) the energy consumption of the manganese dioxide prepared by the in-situ solid-phase electrolysis process is lower, and the yield is higher. Figure 11a and Figure 11b The two kinds of manganese dioxide prepared by the separate solid-phase electrolytic oxidation have different morphologies, and the manganese dioxide prepared by the in-situ solid-phase electrolysis has a significantly different morphology. Figure 2a and Figure 3a Compared with the in-situ solid-phase electrolysis, the morphology of the manganese dioxide prepared by the separate solid-phase electrolytic oxidation is significantly different, the overall size of the nanoparticles of the manganese dioxide prepared by the in-situ solid-phase electrolysis is significantly increased, and the specific surface area is reduced. The different morphology and specific surface area enable the manganese dioxide prepared by the in-situ solid-phase electrolysis to be applied in different fields.

[0137] In addition, from the comparison of Comparative Example 3 and Example 1, when the sum of the mass of the manganese dioxide produced by the anode and the mass of the lead produced by the cathode is one ton, the energy consumption (i.e., the energy consumption per ton of combined products) is 448.7 kWh, and the energy consumption of the separate solid-phase electrolysis process for producing the same mass of products is 770.9 kWh. The in-situ solid-phase electrolysis process saves energy and reduces emissions by about 41.8%.

[0138] It is easy for those skilled in the art to understand that the above advantageous modes can be freely combined and superimposed without conflict. The above is only a preferred embodiment of the present application and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application. The above is only a preferred embodiment of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be regarded as the protection scope of the present application.

Claims

1. A method for co-producing metallic lead and manganese dioxide through solid-phase electrolysis in the same tank, characterized in that, Includes the following steps: Electrode preparation: lead-containing solid waste is mixed with deionized water to form a paste, which is then coated onto a cathode plate and wrapped in a bag to form a solid cathode; manganese oxide precursor is mixed with deionized water to form a paste, which is then coated onto an anode plate and wrapped in a bag to form a solid anode. The solid-phase cathode and the solid-phase anode are placed in the same electrolytic tank, and a sodium sulfate aqueous solution with an initial pH of 6.7±0.2 and a concentration of 180g / L-220g / L is used as an electrolyte to perform electrolysis at 28℃-32℃ or 78℃-82℃, the anode current density is controlled to be 90A / m 2 ~110A / m 2 , and the cathode current density is twice the anode current density; when the electrolysis temperature is 28℃-32℃, the product manganese dioxide is in a nanospherical structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1400kWh-1500kWh, the specific capacitance is 80F / g-90F / g, the chemical composition mass fraction of the product metal lead satisfies Pb content≥96.0%, Sb content≤0.9%, As content≤0.7%, the energy consumption per ton of metal lead is 950kWh-1000kWh; when the electrolysis temperature is 78℃-82℃, the product manganese dioxide is in a nanorod structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1000kWh-1100kWh, the specific capacitance is 60F / g-70F / g, the chemical composition mass fraction of the product metal lead satisfies Pb content≥96.0%, Sb content≤0.9%, As content≤0.7%, the energy consumption per ton of metal lead is 700kWh-750kWh; when the initial pH of the sodium sulfate aqueous solution used as the electrolyte is 6.7±0.2, the concentration is 180g / L-220g / L, the electrolysis temperature is 78℃-82℃, and the anode current density is 90A / m 2 ~110A / m 2 , the total energy consumption per ton of co-produced metal lead and manganese dioxide is <500kWh; Product processing: After electrolysis, the cathode stripping product is cleaned and dried to obtain metallic lead, and the anode stripping product is cleaned and dried to obtain manganese dioxide. Electrolyte circulation: After each electrolysis, the pH of the electrolyte is adjusted to 6.7±0.2 and then recycled; after every 5 electrolysis cycles, manganese is removed from the electrolyte.

2. The method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank according to claim 1, characterized in that, The lead-containing solid waste includes at least one of waste lead paste, lead-containing tailings, and lead-containing tailings; the manganese oxide precursor includes at least one of manganese minerals and manganese-containing solid oxides obtained by reacting an aqueous solution of divalent manganese ions with sodium hydroxide.

3. The method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank according to claim 1, characterized in that, The electrolyte circulation also includes electrolyte manganese removal: Sodium hydroxide is added to the electrolyte to adjust the pH to 7.5±0.2, so that the manganese ions in the electrolyte are precipitated as manganese tetroxide. The manganese tetroxide is returned as a manganese raw material to the electrode preparation step for the preparation of anode paste. The electrolyte after manganese removal is recycled for the next electrolysis.

4. The method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank according to claim 1, characterized in that, Each electrolysis session lasts 3-6 hours.

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