Method for co-producing metal lead and manganese dioxide through same-tank solid-phase electrolysis

Abstract

The invention discloses a method for co-producing metal lead and manganese dioxide through same-tank solid-phase electrolysis, and relates to the technical field of solid-phase electrolysis. According to the method, the lead-containing solid waste serves as a solid-phase cathode, a manganese-containing precursor serves as a solid-phase anode, in the same electrolytic bath, a sodium sulfate aqueous solution with the initial pH being 6-8 and the concentration being 10-400 g / L serves as electrolyte, electrolysis is conducted at the temperature of 20-95 DEG C, the anode current density is controlled to be 10-1000 A / m < 2 >, and the cathode current density is two times that of the anode current density; after electrolysis, stripping a product to obtain metal lead meeting YS / T 71-2013 lead bullion Pb96.0 C standard requirements and a manganese dioxide energy storage material with high additional value, high specific capacitance and controllable morphology; adjusting the pH value of the electrolyte to 6-8, and then recycling to ensure continuous production. Compared with traditional hydrometallurgy, the total energy consumption of co-production of metal lead and manganese dioxide per ton is reduced by 70.3%, and the production efficiency is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of solid-phase electrolysis, and in particular to a method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank. Background Art

[0002] Achieving clean production and energy conservation and carbon reduction are core goals of industrial society and my country's "dual carbon" strategy. Therefore, developing technologies that can achieve energy conservation and emission reduction, efficiently couple solid waste treatment, and scale up the production of high-value-added manganese dioxide (MnO2) energy storage materials has become a key research direction in this field. As a high-valent, stable oxide of manganese, MnO2 has high added value due to its important applications in battery energy storage. At the same time, the heavy metal lead in lead-containing solid waste, if improperly disposed of, poses a serious threat to the environment and human health, necessitating the development of effective methods for its recovery.

[0003] Currently, the industrial production of MnO2 primarily relies on the electrolytic hot manganese sulfate method, which involves electrolytic deposition of MnO2 at the anode and hydrogen evolution at the cathode. Hydrometallurgical processes for treating lead-containing solid waste generally employ a "reduction leaching-electrodeposition" method, where metallic lead is electrodeposited at the cathode and oxygen evolution occurs at the anode. Both existing processes produce the target product at only a single electrode (the former anode, the latter cathode). The electrical energy at the other electrode is consumed by the gas evolution reaction and is not effectively utilized, resulting in significant energy waste. Specifically, the energy consumption for producing MnO2 alone can reach 2500kWh / t to 3000kWh / t, while the energy consumption for producing metallic lead alone, via electrodeposition, is as high as 500kWh / t to 900kWh / t. Summary of the Invention

[0004] In response to the deficiencies in the prior art, the present invention couples the solid-phase electrolysis of MnO2 and metallic lead processes to develop a method for synchronously recovering metallic lead at the cathode through solid-phase electrolysis, while directly converting it into a high-value-added MnO2 product at the anode, thereby significantly reducing energy consumption and improving resource utilization efficiency. This method has important theoretical and practical significance for promoting energy conservation, consumption reduction, quality improvement and efficiency enhancement in related hydrometallurgical processes.

[0005] To this end, the present invention provides a method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank, comprising the following steps: Electrode preparation: Mix lead-containing solid waste with deionized water to form a paste, apply it to the cathode plate, and then bag it to make a solid-phase cathode; mix manganese oxide precursor with deionized water to form a paste, apply it to the anode plate, and then bag it to make a solid-phase anode; Electrolysis in the same tank: The solid cathode and solid anode are placed in the same electrolytic tank, and an aqueous sodium sulfate solution with an initial pH of 6-8 and a concentration of 10g / L-400g / L is used as the electrolyte. Electrolysis is carried out at 20°C-95°C, and the anode current density is controlled to be 10A / m 2 ~1000A / m 2 , the cathode current density is twice the anode current density; Product processing: After the electrolysis is completed, the cathode product is stripped, cleaned, and dried to obtain metallic lead, and the anode product is stripped, cleaned, and dried to obtain manganese dioxide; Electrolyte circulation: After each electrolysis, adjust the pH of the electrolyte to 6~8 and then recycle it.

[0006] Furthermore, 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-containing solid oxides obtained by reacting a manganese mineral, an aqueous solution of divalent manganese ions, and sodium hydroxide.

[0007] Furthermore, in the same-tank electrolysis step, a sodium sulfate aqueous solution with an initial pH of 6.2-7.2 and a concentration of 100 g / L-300 g / L is used as the electrolyte.

[0008] Furthermore, in the same-tank electrolysis step, the electrolysis temperature is 25°C to 40°C or 60°C to 90°C.

[0009] Furthermore, in the electrolysis step, the anode current density is controlled to be 50A / m 2 ~200A / m 2 .

[0010] Furthermore, in the same tank electrolysis step, an aqueous sodium sulfate solution with an initial pH of 6.7±0.2 and a concentration of 180g / L~220g / L is used as the electrolyte, the electrolysis temperature is 28℃~32℃ or 78℃~82℃, and the anode current density during the electrolysis process is controlled to be 90A / m 2 ~110A / m 2 .

[0011] Furthermore, when the electrolysis temperature is 28°C to 32°C, the manganese dioxide product has a nano-spherical structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide production is 1400kWh to 1500kWh, and the specific capacitance is 80F / g to 90F / g; the chemical composition mass fraction of the product metallic lead satisfies the following requirements: Pb content ≥ 96.0%, Sb content ≤ 0.9%, As content ≤ 0.7%, and the energy consumption per ton of metallic lead production is 950kWh to 1000kWh. Furthermore, when the electrolysis temperature is 78°C~82°C: the product manganese dioxide has a nano-rod structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1000kWh~1100kWh, and the specific capacitance is 60F / g~70F / g; the mass fraction of the chemical composition of the product metallic lead satisfies: Pb content ≥96.0%, Sb content ≤0.9%, As content ≤0.7%, and the energy consumption per ton of metallic lead is 700kWh~750kWh.

[0012] Furthermore, in the same tank electrolysis step, an aqueous sodium sulfate solution with an initial pH of 6.7±0.2 and a concentration of 180 g / L to 220 g / L is used as the electrolyte, the electrolysis temperature is 78°C to 82°C, and the anode current density is 90 A / m 2 ~110A / m 2 The total energy consumption per ton of co-produced metallic lead and manganese dioxide is less than 500kWh.

[0013] Furthermore, the electrolyte circulation further comprises: After completing every five electrolysis cycles, the electrolyte is demanganized by adding sodium hydroxide to the electrolyte to adjust the pH to 7.5±0.2, so that the manganese ions in the electrolyte are precipitated in the form of manganese tetraoxide. The manganese tetraoxide is returned to the electrode preparation step as a manganese raw material for preparing the anode paste. The electrolyte after demanganization is circulated for the next electrolysis.

[0014] Furthermore, the time of each electrolysis is 3h-6h.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The method provided by the present invention for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank simultaneously produces a manganese dioxide energy storage material with high added value, high specific capacitance and controllable morphology at the anode while treating lead-containing solid waste at the cathode to produce metallic lead that meets the YS / T 71-2013 standard for crude lead (Pb96.0C). Compared with traditional hydrometallurgical processes, this method reduces the total energy consumption per ton of co-produced metallic lead and manganese dioxide by 70.3% and significantly improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments described in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0017] Figure 1 The XRD spectrum of the solid-phase electrolysis co-production of metallic lead and manganese dioxide in the same tank provided by the embodiment of the present invention; wherein, Figure 1a is the XRD pattern of the anodic manganese dioxide product electrolyzed in the same tank at different electrolysis temperatures. Figure 1 b is the XRD pattern of the cathode metal lead product electrolyzed in the same tank at different electrolysis temperatures.

[0018] Figure 2a This is the SEM morphology of the anodic manganese dioxide product prepared by electrolysis in the same tank at 80° C. provided in Example 1 of the present invention.

[0019] Figure 2b This is the SEM morphology of the cathode metal lead product prepared by electrolysis in the same tank at 80°C provided in Example 1 of the present invention.

[0020] Figure 3a This is the SEM morphology of the anodic manganese dioxide product prepared by electrolysis in the same tank at 30° C. provided in Example 2 of the present invention.

[0021] Figure 3b This is the SEM morphology of the cathode metal lead product prepared by electrolysis in the same tank at 30°C provided in Example 2 of the present invention.

[0022] Figure 4 The cyclic voltammetry curves of the manganese dioxide product prepared by electrolysis anode in the same tank at 80° C. provided in Example 1 of the present invention at different scan rates.

[0023] Figure 5 The charge and discharge curves of the manganese dioxide product prepared by electrolysis anode in the same tank at 80°C provided in Example 1 of the present invention at different current densities.

[0024] Figure 6 This is the electrochemical impedance spectrum of the manganese dioxide product prepared by the same-tank electrolysis anode at 80°C provided in Example 1 of the present invention.

[0025] Figure 7 The cyclic voltammetry curves of the manganese dioxide product prepared by electrolysis anode in the same tank at 30° C. provided in Example 2 of the present invention at different scan rates.

[0026] Figure 8 The charge and discharge curves of the manganese dioxide product prepared by electrolysis anode in the same tank at 30°C provided in Example 2 of the present invention at different current densities.

[0027] Figure 9 This is the electrochemical impedance spectrum of the manganese dioxide product prepared by the same electrolytic anode at 30°C provided in Example 2 of the present invention.

[0028] Figure 10 This is a cycle stability test curve of a supercapacitor device made of a nano-spherical manganese dioxide product prepared by electrolysis anode in the same tank at 30°C provided in Example 2 of the present invention.

[0029] Figure 11aThis is the SEM morphology of the manganese dioxide product prepared by solid-phase electrolysis alone at 80° C. provided in Comparative Example 3 of the present invention.

[0030] Figure 11b This is the SEM morphology of the manganese dioxide product prepared by solid-phase electrolysis alone at 30° C. provided in Comparative Example 4 of the present invention. DETAILED DESCRIPTION

[0031] In order to better understand the above technical solution, the technical solution of the embodiment of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiment of the present application and the specific features in the embodiment are detailed descriptions of the technical solution of the embodiment of the present application, rather than limitations on the technical solution of the present application. In the absence of conflict, the embodiment of the present application and the technical features in the embodiment can be combined with each other.

[0032] An embodiment of the present invention provides a method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank, comprising the following steps: Electrode preparation: Mix lead-containing solid waste with deionized water to form a paste, apply it to the cathode plate, and then bag it to make a solid-phase cathode; mix manganese oxide precursor with deionized water to form a paste, apply it to the anode plate, and then bag it to make a solid-phase anode; Electrolysis in the same tank: The solid cathode and solid anode are placed in the same electrolytic tank, and an aqueous sodium sulfate solution with an initial pH of 6-8 and a concentration of 10g / L-400g / L is used as the electrolyte. Electrolysis is carried out at 20°C-95°C, and the anode current density is controlled to be 10A / m 2 ~1000A / m 2 , the cathode current density is twice the anode current density; Product processing: After the electrolysis is completed, the cathode product is stripped, cleaned, and dried to obtain metallic lead, and the anode product is stripped, cleaned, and dried to obtain manganese dioxide; Electrolyte circulation: To ensure the electrolysis effect of continuous production, the pH of the electrolyte is adjusted to 6~8 after each electrolysis and then recycled.

[0033] Understandably, the existing technology for treating lead-containing solid waste to recover metallic lead and producing manganese dioxide through electrolysis requires two separate electrolysis processes. In both processes, the target product (metallic lead or manganese dioxide) is generated only at a single electrode (cathode or anode), while gassing (hydrogen or oxygen evolution) occurs at the other electrode. This results in approximately half of the electrical energy being wasted and not used for product production. Therefore, the existing technology for treating lead-containing solid waste and producing manganese dioxide is subject to high energy consumption and costs, and the acidic or alkaline electrolyte released by the gassing reaction can also pose a risk to operators and equipment.

[0034] The method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank provided by an embodiment of the present invention simultaneously produces a high-value-added, high-specific capacitance, and morphology-controllable manganese dioxide energy storage material at the anode while treating lead-containing solid waste at the cathode to produce metallic lead that meets the requirements of the YS / T 71-2013 crude lead (Pb96.0C) standard. Compared with traditional hydrometallurgical processes, this method reduces the total energy consumption per ton of co-produced metallic lead and manganese dioxide by 70.3% and significantly improves production efficiency.

[0035] In some embodiments, 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-containing solid oxides obtained by reacting a manganese mineral, an aqueous solution of divalent manganese ions, and sodium hydroxide.

[0036] Specifically, lead-containing solid waste includes but is not limited to waste lead paste, lead-containing tailings, and lead-containing tailings (such as galena PbS and cerussite). Using lead-containing solid waste as cathode raw materials not only allows for large-scale and safe disposal of high-risk solid waste, reducing environmental risks, but also allows for efficient recovery of valuable metallic lead resources. The manganese oxide precursor is selected from low-valent manganese-containing minerals (such as manganite MnOOH, sarsenite MnO, and rhodochrosite MnCO3), or is prepared by a simple precipitation method (reacting an aqueous solution of divalent manganese ions with sodium hydroxide to form a manganese-containing solid oxide precipitate, such as Mn3O4, Mn2O3, and Mn(OH)2).

[0037] Among them, in the same tank electrolysis step, the electrolysis temperature is preferably 25°C~40°C or 60°C~90°C, and the electrolysis temperature is more preferably 28°C~32°C or 78°C~82°C. Furthermore, the energy consumption is lowest and the electrolysis temperature is more preferably 80°C. At this time, the manganese dioxide product morphology is nano-stick-shaped, and the electrochemical energy storage performance is good. It is more preferably 30°C. At this time, the manganese dioxide product morphology is nano-sphere-shaped. Figure 1 The results of solid-phase electrolysis co-production of metallic lead in the same tank at different temperatures are given. Figure 1 b) with manganese dioxide ( Figure 1 a) XRD pattern: It can be seen that within the temperature range studied, the precursor reaction raw materials can all be solid-phase electro-oxidized to γ-type manganese dioxide, and the cathode lead-containing solid waste can all be solid-phase electro-reduced to metallic lead. No other impurity peaks are observed in the products, indicating excellent electrolysis effect.

[0038] The initial pH of the electrolyte is preferably 6.2 to 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 reduced. When the pH of the electrolyte is greater than 8, the anode current efficiency is reduced. At the same time, too high a pH may cause the metallic lead generated at the cathode to dissolve and contaminate the purity of the anode manganese dioxide product.

[0039] Among them, the electrolyte concentration is preferably 100g / L~300g / L sodium sulfate aqueous solution as the electrolyte, more preferably 180g / L~220g / L sodium sulfate aqueous solution as the electrolyte, most preferably 200g / L sodium sulfate aqueous solution as the electrolyte.

[0040] The anode current density during electrolysis is preferably 50 A / m 2 ~200A / m 2 , more preferably the anode current density is 90A / m 2 ~110A / m 2 The most preferred anode current density is 100 A / m 2 .

[0041] The process of the present invention is a type of electrolysis process, allowing for convenient control of electrolysis conditions. The electrolysis temperature is controlled by a heating device and a temperature monitoring device, the initial pH of the electrolyte is adjusted by adding H2SO4 or NaOH, and the electrolyte concentration is controlled by controlling the amount of sodium sulfate added. During the solid-phase electrolysis process in the same tank, the cathode and anode solid materials gain or lose electrons at the cathode and anode, respectively, under the action of an applied electric field. This breaks the original chemical bonds between the anode and cathode solid materials. Simultaneously, the high-valent lead element at the cathode is reduced to metallic lead, and the low-valent manganese element at the anode is oxidized to manganese dioxide, thereby achieving solid-phase electrolysis at both the cathode and anode to produce the target product. It is also noted that the cathode solid material, scrap lead paste, contains a large amount of lead sulfate (typically >50% by mass). During the solid-phase electroreduction process, sulfate ions are released into the electrolyte due to the breaking of ionic bonds. Simultaneously, the anode reaction continuously generates hydrogen ions, which combine with the sulfate ions to form sulfuric acid. This results in a continuous accumulation of sulfuric acid and a continuous decrease in the electrolyte pH during the electrolysis process. The generated sulfuric acid can be neutralized by adding low-cost sodium hydroxide, thereby achieving the regeneration cycle of the electrolyte.

[0042] In some embodiments, when the electrolysis temperature is 28°C~32°C: the product manganese dioxide has a nano-spherical structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1400kWh~1500kWh, and the specific capacitance is 80F / g~90F / g; the mass fraction of the chemical composition of the product metallic lead satisfies: Pb content ≥96.0%, Sb content ≤0.9%, As content ≤0.7%, and the energy consumption per ton of metallic lead is 950kWh~1000kWh.

[0043] In some embodiments, when the electrolysis temperature is 78°C~82°C: the product manganese dioxide has a nano-rod structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide is 1000kWh~1100kWh, and the specific capacitance is 60F / g~70F / g; the mass fraction of the chemical composition of the product metallic lead satisfies: Pb content ≥96.0%, Sb content ≤0.9%, As content ≤0.7%, and the energy consumption per ton of metallic lead is 700kWh~750kWh.

[0044] In some embodiments, in the electrolysis step in the same tank, an aqueous sodium sulfate solution with an initial pH of 6.7±0.2 and a concentration of 180 g / L to 220 g / L is used as the electrolyte, the electrolysis temperature is 78°C to 82°C, and the anode current density is 90 A / m 2 ~110A / m 2 The total energy consumption per ton of co-produced metallic lead and manganese dioxide is less than 500kWh.

[0045] In some embodiments, the electrolyte circulation further includes: removing manganese from the electrolyte after every 5 electrolysis cycles, adding sodium hydroxide to the electrolyte to adjust the pH to 7.5±0.2, so that the manganese ions in the electrolyte are precipitated in the form of manganese tetraoxide, and the manganese tetraoxide is returned to the electrode preparation step as a manganese raw material for preparing the anode paste. The electrolyte after manganese removal is circulated for the next electrolysis.

[0046] Specifically, to achieve continuous production and ensure the electrolysis effect, the pH of the electrolyte after electrolysis must be adjusted and the manganese ions in the electrolyte must be recovered. Sodium hydroxide is used to adjust the electrolyte pH and recover the manganese ions. Sodium hydroxide is added to the electrolyte after electrolysis in the same tank (at this point, the electrolyte pH is approximately 4.3) to neutralize the generated sulfuric acid, adjusting the electrolyte pH to approximately 6.7. Electrolysis can then be continued. After five electrolysis cycles, sodium hydroxide is added to adjust the electrolyte pH to approximately 7.5 to recover the manganese ions in the electrolyte. The manganese ions will then settle as a brown-yellow manganese tetraoxide precipitate at the bottom of the electrolytic tank. After filtration, washing, and drying, the manganese tetraoxide precursor can be recovered and returned to the electrolysis process, thus achieving electrolyte regeneration and continuous production.

[0047] In some embodiments, the duration of each electrolysis is 3 h to 6 h.

[0048] Specifically, excessively long electrolysis times can lead to increasing electrolyte acidity and manganese ion concentration, reducing cathode current efficiency and the electrochemical energy storage performance of the anode manganese dioxide product. Excessively short electrolysis times can lead to incomplete solid-phase electrolysis and incomplete reaction of the reactants. Therefore, the final electrolysis time was determined to be 3-6 hours.

[0049] Example 1 A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank comprises the following steps: (1) Weigh 1.5 g of manganese oxide and 2.3 g of lead-containing solid waste, add 1.2 mL and 1.5 mL of deionized water to the two solid powders respectively and stir thoroughly to mix.

[0050] (2) The mixed reaction materials are coated on square electrode plates, with the area ratio of the anode and cathode plates being 1:2.

[0051] (3) The electrode coated with the reaction raw material paste was dried at 80°C for 1 hour and then wrapped with a square cloth bag material; then, the electrode was firmly tied with a polytetrafluoroethylene braided rope with a diameter of 1 mm to form a bagged electrode.

[0052] (4) Electrolysis was performed in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7. The anode current density of the electrolysis process was 100 A / m 2 , cathode current density is 200A / m 2 The electrolysis temperature is 80°C, the electrolysis time is 200 min, the cathode plate of the electrolysis system is a bagged cathode with lead-containing solid waste as the solid reaction raw material, and the anode plate is a bagged anode made of manganese oxide as the reaction raw material.

[0053] (5) After electrolysis, the cathode electroreduction product was peeled off using a stainless steel blade and then rinsed twice with deionized water and anhydrous ethanol. To minimize oxidation of the product, the washed lead metal product was placed in a vacuum drying oven at 90°C for 1 hour.

[0054] (6) After electrolysis, use a glass sheet to peel off the anode electro-oxidation product, wash it with deionized water several times, and then use deionized water to flush the electro-oxidation product into a centrifuge tube and spin it at 6000 r·min. -1 The product was centrifuged at a speed of 10 min, the supernatant was discarded and the product was dried in an oven at 80°C for 2 hours to obtain a dry manganese dioxide product.

[0055] The dried product was weighed to obtain 1.51 g of metallic lead product and 1.03 g of manganese dioxide product.

[0056] The main technical indicators of the Pb-MnO2 same-tank solid-phase electrolysis process in Example 1 are: energy consumption per ton of metallic lead produced is 733.7 kWh, which meets the YS / T 71-2013 standard for crude lead (Pb96.0C); energy consumption per ton of manganese dioxide produced is 1079.8 kWh, with a manganese dioxide yield of 99.60%, and an electrochemical energy storage performance indicator of specific capacitance of 66.8 F / g. In contrast, the commercially available electrolytic manganese dioxide product from Sinopharm Group has a specific capacitance of only 27.2 F / g. The energy consumption per ton of combined manganese dioxide produced at the anode and metallic lead produced at the cathode (i.e., energy consumption per ton of combined product) is 448.7 kWh. The energy consumption of conventional hydrometallurgical processes for producing the same mass of product is 1510 kWh. This process achieves energy savings and emission reductions of approximately 70.3%.

[0057] The SEM morphology of the manganese dioxide product prepared in Example 1 is as follows: Figure 2a As shown, the SEM morphology of the metal lead product prepared in Example 1 is as follows Figure 2b As shown. Figure 2a It can be seen that the microstructure of the prepared MnO2 product presents a nanorod structure, the length of the nanorod particles is about 30nm~90nm, and the diameter is about 5nm~20nm, which is consistent with the Figure 11a The morphology of MnO2 obtained by electrooxidation at 80℃ is obviously different. Figure 2b It can be seen that the microstructure of the prepared metallic lead product presents a relatively dense block structure of sponge lead. The relatively compact microstructure increases the mechanical strength of the macro metallic lead product, which is beneficial to the operation of collecting its products.

[0058] The cyclic voltammetry curve, charge-discharge curve and electrochemical impedance spectroscopy of the manganese dioxide product prepared in Example 1 are as follows: Figure 4 、 Figure 5 and Figure 6 As shown in FIG, it can be seen that the area enclosed by the cyclic voltammetry curves of the MnO2 product prepared by electrolysis in the same tank at different scan rates increases with the increase of the scan 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 cyclic voltammetry curve enclosed area and discharge time of the manganese dioxide product prepared in Example 1 are relatively small, and the impedance is relatively high, which reflects that the charge transfer and ion diffusion in its electrochemical energy storage process are relatively difficult.

[0059] Example 2 A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank comprises the following steps: (1) Weigh 1.5 g of manganese oxide and 2.3 g of lead-containing solid waste, add 1.2 mL and 1.5 mL of deionized water to the two solid powders respectively and stir thoroughly to mix.

[0060] (2) The mixed reaction materials are coated on square electrode plates, with the area ratio of the anode and cathode plates being 1:2.

[0061] (3) The electrode coated with the reaction raw material paste was dried at 80°C for 1 hour and then wrapped with a square cloth bag material; then, the electrode was firmly tied with a polytetrafluoroethylene braided rope with a diameter of 1 mm to form a bagged electrode.

[0062] (4) Electrolysis was performed in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7. The anode current density of the electrolysis process was 100 A / m 2 , cathode current density is 200A / m 2 The electrolysis temperature is 30°C, the electrolysis time is 335 minutes, the cathode plate of the electrolysis system is a bagged cathode with lead-containing solid waste as the solid reaction raw material, and the anode plate is a bagged anode made of manganese oxide as the reaction raw material.

[0063] (5) After electrolysis, the cathode electroreduction product was peeled off using a stainless steel blade and then rinsed twice with deionized water and anhydrous ethanol. To minimize oxidation of the product, the washed lead metal product was placed in a vacuum drying oven at 90°C for 1 hour.

[0064] (6) After electrolysis, use a glass sheet to peel off the anode electro-oxidation product, wash it with deionized water several times, and then use deionized water to flush the electro-oxidation product into a centrifuge tube and spin it at 6000 r·min. -1 The product was centrifuged at a speed of 10 min, the supernatant was discarded and the product was dried in an oven at 80°C for 2 hours to obtain a dry manganese dioxide product.

[0065] The dried product was weighed to obtain 1.45 g of metallic lead product and 1.07 g of manganese dioxide product.

[0066] The main technical indicators of the Pb-MnO2 same-tank solid-phase electrolysis process in Example 2 are: energy consumption per ton of metallic lead production is 972.9 kWh, and the metallic lead meets the YS / T 71-2013 crude lead Pb96.0C standard requirements; energy consumption per ton of manganese dioxide production is 1435.8 kWh, the manganese dioxide yield is 99.03%, and the electrochemical energy storage performance index specific capacitance is 84.7 F / g.

[0067] The SEM morphology of the manganese dioxide product prepared in Example 2 is as follows: Figure 3a As shown, the SEM morphology of the metal lead product prepared in Example 1 is as follows Figure 3b As shown. Figure 3a It can be seen that the MnO2 product prepared at a low temperature of 30℃ presents a nano-spherical structure that is aggregated together. The size of the nano-spheres is between 50nm and 150nm, which is better than that of the Figure 11bThe size of MnO2 nanospheres obtained by electrooxidation at 30℃ is much larger (10nm~100nm). Figure 3b It can be seen that the microscopic morphology of the cathode metal lead product does not change much at a low temperature of 30°C, and it still has a sponge lead morphology with a rough surface.

[0068] The cyclic voltammetry curve, charge-discharge curve and electrochemical impedance spectroscopy of the manganese dioxide product prepared in Example 2 are as follows: Figure 7 、 Figure 8 and Figure 9 As shown, it can be seen that the area surrounded by the cyclic voltammetry curves of the MnO2 product prepared by electrolysis in the same tank at different sweep rates increases with the increase of the sweep rate, which reflects that the MnO2 material has good capacitive charge storage characteristics, and the approximately rectangular cyclic voltammetry curve reflects its ideal capacitance behavior. In addition, the area and discharge time surrounded by the cyclic voltammetry curve of the manganese dioxide product prepared in Example 2 are both greater than the manganese dioxide product prepared in Example 1, and both the diffusion impedance and the charge transfer impedance are overall less than the manganese dioxide product prepared in Example 1, indicating that its capacitance performance is better than the manganese dioxide product prepared in Example 1, which reflects the significant effect of temperature on the electrochemical energy storage performance of the manganese dioxide product prepared by solid-phase electrolysis in the same tank.

[0069] The cyclic stability test curve of the manganese dioxide product prepared in Example 2 is as follows: Figure 10 As shown in the figure, it can be seen that the product exhibits good capacity retention and charge-discharge cycle stability. After 10,000 charge-discharge cycles, the capacity retention rate is as high as 97.8%, and the coulombic efficiency is as high as 98%, further verifying its excellent electrochemical energy storage performance.

[0070] Example 3 A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank comprises the following steps: (1) Weigh 1.5 g of manganese oxide and 3.8 g of lead-containing solid waste, add 1.2 mL and 1.5 mL of deionized water to the two solid powders respectively and stir thoroughly to mix.

[0071] (2) The mixed reaction materials are coated on square electrode plates, with the area ratio of the anode and cathode plates being 1:2.

[0072] (3) The electrode coated with the reaction raw material paste was dried at 80°C for 1 hour and then wrapped with a square cloth bag material; then, the electrode was firmly tied with a polytetrafluoroethylene braided rope with a diameter of 1 mm to form a bagged electrode.

[0073] (4) Electrolysis was performed in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7. The anode current density of the electrolysis process was 200 A / m2 , cathode current density is 400A / m 2 The electrolysis temperature is 80°C, the electrolysis time is 335 minutes, the cathode plate of the electrolysis system is a bagged cathode with lead-containing solid waste as the solid reaction raw material, and the anode plate is a bagged anode made of manganese oxide as the reaction raw material.

[0074] (5) After electrolysis, the cathode electroreduction product was peeled off using a stainless steel blade and then rinsed twice with deionized water and anhydrous ethanol. To minimize oxidation of the product, the washed lead metal product was placed in a vacuum drying oven at 90°C for 1 hour.

[0075] (6) After electrolysis, use a glass sheet to peel off the anode electro-oxidation product, wash it with deionized water several times, and then use deionized water to flush the electro-oxidation product into a centrifuge tube and spin it at 6000 r·min. -1 The product was centrifuged at a speed of 10 min, the supernatant was discarded and the product was dried in an oven at 80°C for 2 hours to obtain a dry manganese dioxide product.

[0076] The dried product was weighed to obtain 2.63 g of metallic lead product and 0.92 g of manganese dioxide product.

[0077] The main technical indicators of the Pb-MnO2 same-tank solid-phase electrolysis process in Example 3 are: energy consumption per ton of metallic lead production is 849.8 kWh, and the metallic lead meets the YS / T 71-2013 crude lead Pb96.0C standard requirements; energy consumption per ton of manganese dioxide production is 2335.3 kWh, the manganese dioxide yield is 93.72%, and the electrochemical energy storage performance indicator specific capacitance is 58.6 F / g.

[0078] Comparative Example 1 Effect of Initial Electrolyte pH on Co-production of Metallic Lead and Manganese Dioxide in the Same Tank Solid-Phase Electrolysis (I) In the continuous electrolysis production process, the adjustment of the initial pH of the electrolyte is the key. The following introduces the electrolysis effect in the same tank when the initial pH of the electrolyte is 0.29.

[0079] A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank comprises the following steps: (1) Weigh 1.5 g of manganese oxide and 3.8 g of lead-containing solid waste, add 1.2 mL and 1.5 mL of deionized water to the two solid powders respectively and stir thoroughly to mix.

[0080] (2) The mixed reaction materials are coated on square electrode plates, with the area ratio of the anode and cathode plates being 1:2.

[0081] (3) The electrode coated with the reaction raw material paste was dried at 80°C for 1 hour and then wrapped with a square cloth bag material; then, the electrode was firmly tied with a polytetrafluoroethylene braided rope with a diameter of 1 mm to form a bagged electrode.

[0082] (4) Electrolysis was performed in a mixed aqueous solution of sulfuric acid with an initial pH of 0.29 and sodium sulfate (200 g / L). The anode current density of the electrolysis process was 200 A / m 2 , cathode current density is 400A / m 2 The electrolysis temperature is 80°C, the electrolysis time is 335 minutes, the cathode plate of the electrolysis system is a bagged cathode with lead-containing solid waste as the solid reaction raw material, and the anode plate is a bagged anode made of manganese oxide as the reaction raw material.

[0083] (5) After electrolysis, the cathode electroreduction product was peeled off using a stainless steel blade and then rinsed twice with deionized water and anhydrous ethanol. To minimize oxidation of the product, the washed lead metal product was placed in a vacuum drying oven at 90°C for 1 hour.

[0084] (6) After electrolysis, use a glass sheet to peel off the anode electro-oxidation product, wash it with deionized water several times, and then use deionized water to flush the electro-oxidation product into a centrifuge tube and spin it at 6000 r·min. -1 The product was centrifuged at a speed of 10 min, the supernatant was discarded and the product was dried in an oven at 80°C for 2 hours to obtain a dry manganese dioxide product.

[0085] The dried product was weighed to obtain 2.63 g of electro-reduction product and 0.88 g of manganese dioxide product.

[0086] The main technical indicators of the Pb-MnO2 same-tank solid-phase electrolysis process in Comparative Example 1 are: energy consumption per ton of metallic lead is 896.4 kWh, desulfurization rate is 85.3%, and lead recovery rate is 93.8%. The above indicators are significantly lower than the electrolysis effect of neutral electrolyte; energy consumption per ton of manganese dioxide is 2350.6 kWh, manganese dioxide yield is 99.7%, and electrochemical energy storage performance index specific capacitance is 60.3 F / g. The above indicators are basically the same as the electrolysis effect of neutral electrolyte.

[0087] By comparing Comparative Example 1 and Example 3, the results show that the anodic electro-oxidation effect in the acidic electrolyte remains essentially unchanged, but the cathodic electro-reduction effect decreases dramatically. The energy consumption for electro-reduction of lead-containing solid waste increases by 22.1% compared to that in the neutral electrolyte, the desulfurization rate decreases by 14%, and the lead recovery rate decreases by approximately 6%. During the same-tank electrolysis process, the pH value continuously decreases due to the continuous release of sulfate ions during the cathode lead-containing solid waste reduction process and the release of hydrogen ions during the anodic reaction. Therefore, before each electrolysis cycle, the pH value needs to be readjusted to approximately 6.7 using sodium hydroxide to ensure optimal electrolysis results.

[0088] Comparative Example 2 Effect of Initial Electrolyte pH on Co-production of Metallic Lead and Manganese Dioxide in the Same Tank Solid-Phase Electrolysis (II) In the continuous electrolysis production process, the adjustment of the initial pH of the electrolyte is the key. The following introduces the electrolysis effect in the same tank when the initial pH of the electrolyte is 11.5.

[0089] (1) Weigh 1.5 g of manganese oxide and 3.8 g of lead-containing solid waste, add 1.2 mL and 1.5 mL of deionized water to the two solid powders respectively and stir thoroughly to mix.

[0090] (2) The mixed reaction materials are coated on square electrode plates, with the area ratio of the anode and cathode plates being 1:2.

[0091] (3) The electrode coated with the reaction raw material paste was dried at 80°C for 1 hour and then wrapped with a square cloth bag material; then, the electrode was firmly tied with a polytetrafluoroethylene braided rope with a diameter of 1 mm to form a bagged electrode.

[0092] (4) Electrolysis was performed in a mixed aqueous solution of NaOH and 200 g / L sodium sulfate with an initial pH of 11.5. The anode current density of the electrolysis process was 200 A / m 2 , cathode current density is 400A / m 2 The electrolysis temperature is 80°C, the electrolysis time is 335 minutes, the cathode plate of the electrolysis system is a bagged cathode with lead-containing solid waste as the solid reaction raw material, and the anode plate is a bagged anode made of manganese oxide as the reaction raw material.

[0093] (5) After electrolysis, the cathode electroreduction product was peeled off using a stainless steel blade and then rinsed twice with deionized water and anhydrous ethanol. To minimize oxidation of the product, the washed lead metal product was placed in a vacuum drying oven at 90°C for 1 hour.

[0094] (6) After electrolysis, use a glass sheet to peel off the anode electro-oxidation product, wash it with deionized water several times, and then use deionized water to flush the electro-oxidation product into a centrifuge tube and spin it at 6000 r·min. -1 The product was centrifuged at a speed of 10 min, the supernatant was discarded and the product was dried in an oven at 80°C for 2 hours to obtain a dry manganese dioxide product.

[0095] The dried product was weighed to obtain 2.72 g of electro-reduction product and 0.56 g of manganese dioxide product.

[0096] The main technical indicators of the Pb-MnO2 same-tank solid-phase electrolysis process in Comparative Example 2 are: energy consumption per ton of metallic lead is 623.4 kWh, desulfurization rate is 99.6%, and lead recovery rate is 98.8%. The above indicators are basically the same as the electrolysis effect of neutral electrolyte; energy consumption per ton of manganese dioxide is 4426.7 kWh, and the electrochemical energy storage performance index specific capacitance is 59.6 F / g. The above indicators are significantly lower than the electrolysis effect of neutral electrolyte.

[0097] By comparing Comparative Example 2 and Example 3, the results show that the cathode electroreduction effect in the alkaline electrolyte remains essentially unchanged, but the effect of the solid-phase electrooxidation of manganese oxide at the anode is greatly reduced, the energy consumption of the anode electrooxidation increases by about 3 times compared to the neutral electrolyte, and the manganese recovery rate decreases by about 53%. Therefore, the pH of the electrolyte should not be too high during the same tank electrolysis process. Sodium hydroxide should be used before each electrolysis cycle to readjust the pH to about 6.7 to ensure the best electrolysis effect.

[0098] Comparative Example 3 A method for preparing manganese dioxide by solid-phase electrooxidation alone A method for preparing manganese dioxide by solid-phase electrooxidation alone comprises the following steps: (1) Weigh 1.5 g of manganese oxide and add 1.8 mL of deionized water and stir thoroughly.

[0099] (2) The mixed reaction materials are coated on a square electrode plate.

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

[0101] (4) Electrolysis was performed in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7. The current density of the electrolysis process was 100 A / m 2 The electrolysis temperature is 80℃, the electrolysis time is 5h, 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.

[0102] (5) After electrolysis, use a glass sheet to peel off the anode electro-oxidation product, wash it with deionized water several times, and then use deionized water to flush the electro-oxidation product into a centrifuge tube and spin it at 6000 r·min. -1 The product was centrifuged at a speed of 10 min, the supernatant was discarded and the product was dried in an oven at 80°C for 2 hours to obtain a dry manganese dioxide product.

[0103] The main technical indicators of the single electro-oxidation electrolysis process of Comparative Example 3 are: energy consumption per ton of manganese dioxide production is 1807.57 kWh, manganese dioxide yield is 97.60%, and electrochemical energy storage performance index specific capacitance is 68.9 F / g.

[0104] The SEM morphology of the manganese dioxide product prepared in Comparative Example 3 is as follows: Figure 11a shown.

[0105] Comparative Example 4 A method for preparing manganese dioxide by solid-phase electrooxidation alone A method for preparing manganese dioxide by solid-phase electrooxidation alone comprises the following steps: (1) Weigh 1.5 g of manganese oxide precursor and add 1.8 mL of deionized water and stir thoroughly.

[0106] (2) The mixed reaction materials are coated on a square electrode plate.

[0107] (3) The electrode coated with the reaction raw material paste was dried at 80°C for 1 hour and then wrapped with a square cloth bag material; then, the electrode was firmly tied with a polytetrafluoroethylene braided rope with a diameter of 1 mm to form a bagged electrode.

[0108] (4) Electrolysis was performed in a 200 g / L sodium sulfate aqueous solution with an initial pH of 6.7 and a current density of 100 A / m 2 The electrolysis temperature is 30°C, 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.

[0109] (5) After electrolysis, use a glass sheet to peel off the anode electro-oxidation product, wash it with deionized water several times, and then use deionized water to flush the electro-oxidation product into a centrifuge tube and spin it at 6000 r·min. -1 The product was centrifuged at a speed of 10 min, the supernatant was discarded and the product was dried in an oven at 80°C for 2 hours to obtain a dry manganese dioxide product.

[0110] The main technical indicators of the single electro-oxidation electrolysis process of Comparative Example 4 are: energy consumption per ton of manganese dioxide production is 2448.6 kWh, manganese dioxide yield is 85.7%, and electrochemical energy storage performance index specific capacitance is 162.1 F / g.

[0111] The SEM morphology of the manganese dioxide product prepared in Comparative Example 4 is as follows: Figure 11b shown.

[0112] By comparing Comparative Example 3 with Example 1, and Comparative Example 4 with Example 2, it can be seen that: 1) the same-tank solid-phase electrolysis process for preparing manganese dioxide has lower energy consumption and higher yield. 2) Figure 11a and Figure 11b Two morphologies of manganese dioxide prepared by solid phase electrooxidation Figure 2a and Figure 3aThe morphology is significantly different compared with that of solid-phase electrolysis in the same tank. The overall size of the nanoparticles of the manganese dioxide product produced by solid-phase electrolysis in the same tank is significantly increased, and the specific surface area is reduced. The different morphologies and specific surface areas enable the manganese dioxide prepared by electrolysis in the same tank to be applied in different fields.

[0113] In addition, by comparing Example 3 with Example 1, when the sum of the mass of manganese dioxide produced at the anode and the metallic lead generated at the cathode is one ton (i.e., the energy consumption per ton of combined product) is 448.7 kWh, and the energy consumption of producing the same mass of product by a single solid-phase electrolysis process is 770.9 kWh. The same-tank electrolysis process saves energy and reduces emissions by approximately 41.8%.

[0114] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application. The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application. These improvements and variations should also be regarded as the scope of protection of the present application.

Claims

1. A method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank, characterized in that: The steps include: Electrode preparation: Mix lead-containing solid waste with deionized water to form a paste, apply it to the cathode plate, and then bag it to make a solid-phase cathode; mix manganese oxide precursor with deionized water to form a paste, apply it to the anode plate, and then bag it to make a solid-phase anode; Electrolysis in the same tank: The solid cathode and solid anode are placed in the same electrolytic tank, and an aqueous sodium sulfate solution with an initial pH of 6-8 and a concentration of 10g / L-400g / L is used as the electrolyte. Electrolysis is carried out at 20°C-95°C, and the anode current density is controlled to be 10A / m 2 ~1000A / m 2 , the cathode current density is twice the anode current density; Product processing: After the electrolysis is completed, the cathode product is stripped, cleaned, and dried to obtain metallic lead, and the anode product is stripped, cleaned, and dried to obtain manganese dioxide; Electrolyte circulation: After each electrolysis, adjust the pH of the electrolyte to 6~8 and then recycle it.

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-containing solid oxides obtained by reacting a manganese mineral, an aqueous solution of divalent manganese ions, and 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: In the same-tank electrolysis step, a sodium sulfate aqueous solution with an initial pH of 6.2-7.2 and a concentration of 100 g / L-300 g / L is used as the electrolyte.

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: In the same tank electrolysis step, the electrolysis temperature is 25°C to 40°C or 60°C to 90°C.

5. 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: In the electrolysis step, the anode current density is controlled to be 50A / m 2 ~200A / m 2 .

6. 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: In the same tank electrolysis step, an aqueous sodium sulfate solution with an initial pH of 6.7±0.2 and a concentration of 180 g / L~220 g / L is used as the electrolyte, the electrolysis temperature is 28°C~32°C or 78°C~82°C, and the anode current density during the electrolysis process is controlled to be 90 A / m 2 ~110A / m 2 .

7. The method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank according to claim 6, characterized in that: When the electrolysis temperature is 28°C to 32°C, the manganese dioxide product has a nano-spherical structure, a yield of not less than 99%, an energy consumption of 1400kWh to 1500kWh per ton of manganese dioxide production, and a specific capacitance of 80F / g to 90F / g. The chemical composition mass fraction of the metallic lead product satisfies the following requirements: Pb content ≥ 96.0%, Sb content ≤ 0.9%, and As content ≤ 0.7%. The energy consumption per ton of metallic lead production is 950kWh to 1000kWh. When the electrolysis temperature is 78°C~82°C: the product manganese dioxide has a nano-rod structure, the yield is not less than 99%, the energy consumption per ton of manganese dioxide production is 1000kWh~1100kWh, and the specific capacitance is 60F / g~70F / g; the chemical composition mass fraction of the product metallic lead satisfies: Pb content ≥96.0%, Sb content ≤0.9%, As content ≤0.7%, and the energy consumption per ton of metallic lead production is 700kWh~750kWh.

8. 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: In the same tank electrolysis step, an aqueous sodium sulfate solution with an initial pH of 6.7±0.2 and a concentration of 180 g / L to 220 g / L is used as the electrolyte, the electrolysis temperature is 78°C to 82°C, and the anode current density is 90 A / m 2 ~110A / m 2 The total energy consumption per ton of co-produced metallic lead and manganese dioxide is less than 500kWh.

9. 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 further comprises: After completing every five electrolysis cycles, the electrolyte is demanganized by adding sodium hydroxide to the electrolyte to adjust the pH to 7.5±0.2, so that the manganese ions in the electrolyte are precipitated in the form of manganese tetraoxide. The manganese tetraoxide is returned to the electrode preparation step as a manganese raw material for preparing the anode paste. The electrolyte after demanganization is circulated for the next electrolysis.

10. The method for co-producing metallic lead and manganese dioxide by solid-phase electrolysis in the same tank according to claim 9, characterized in that: The duration of each electrolysis is 3h-6h.

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