Pretreatment method for lead plaster of waste lead-acid storage battery

Abstract

The invention discloses a pretreatment method of waste lead-acid storage battery lead plaster, and relates to the technical field of lead-acid storage battery treatment, and the pretreatment method comprises the following steps: S1, collecting waste lead-acid storage batteries through a special environment-friendly vehicle; s2, separating and cleaning the positive plate and the negative plate; s3, crushing the positive plate and the negative plate; s4, respectively placing the crushed slag of the positive plate and the negative plate into clear water loaded in a transparent separation tank; s5, the lead-containing metal is placed in distilled water to be cleaned; s6, carrying out wet desulphurization on the lead paste; s7, the metal part and the desulfurized lead paste are subjected to pyrogenic process smelting; and S8, the lead paste is molten into a liquid state, and the lead liquid is mixed with caustic soda so as to be refined. According to the method, the lead paste is subjected to pyrogenic process smelting after being desulfurized, PbSO4 in the lead paste is converted into soluble Na2SO4 and insoluble Pb2CO3 or Pb (OH) 2 precipitates, the PbSO4 and the insoluble Pb2CO3 or Pb (OH) 2 precipitates are conveniently screened out, and therefore effective separation and recovery of the lead paste are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of lead-acid battery treatment, and in particular to a method for pretreating lead paste of waste lead-acid batteries. Background Art

[0002] Lead-acid batteries are mainly composed of positive plates, negative plates, electrolytes, separators, containers and other basic parts. Among them, the positive plate is usually made of lead dioxide, the negative plate is made of lead, and the electrolyte is a sulfuric acid solution. The separator is used to isolate the positive and negative plates to prevent short circuits. Common separator materials include microporous rubber, sintered polyvinyl chloride, glass fiber, polypropylene, etc. The working principle of lead-acid batteries is based on reversible chemical reactions. During the discharge process, the lead dioxide at the positive electrode and the lead at the negative electrode react with the sulfuric acid in the electrolyte to generate lead sulfate and release electrical energy. During the charging process, the lead sulfate will be reduced to lead dioxide and lead, while absorbing electrical energy. In this process, a reversible conversion between electrical energy and chemical energy is achieved.

[0003] However, in the existing treatment process of waste lead-acid batteries, since waste lead-acid batteries contain a large amount of harmful substances such as lead and sulfuric acid, the treatment process requires multiple physical, chemical treatment and smelting steps. These steps are not only technically difficult, but also consume a lot of energy and water resources. At the same time, a large amount of pollutants such as waste water, waste gas and waste residue will be generated during the treatment process, and a large amount of funds need to be invested in environmental protection measures to ensure that the treatment process does not cause secondary pollution to the environment. This will lead to the problems of large investment, high cost and low impurity removal in the existing treatment of waste lead-acid batteries.

[0004] There are related invention patents related to the pretreatment of lead-acid batteries, as follows: Chinese patent application number: CN103050745A, the name of the invention patent is: A method for pretreating lead paste of waste lead-acid batteries. The invention is to obtain waste lead paste after crushing and preliminary separation of waste lead-acid batteries. Use a 0.85mm-0.106mm sieve to wet-screen or dry-screen the waste lead paste to obtain grid and plastic fragment products, and then conduct shaker gravity selection on the under-screen products to obtain diaphragm paper products and pure lead paste. The grid and plastic fragment products and diaphragm paper products can enter the pyrometallurgical smelting system, and the pure lead paste is treated with a new process of leaching with citric acid aqueous solution or sodium carbonate or acetic acid to finally obtain lead powder, which can be directly used to prepare lead-acid batteries. The method of the present invention has simple process equipment, small investment, low cost, and high impurity removal rate. It is a clean, efficient and energy-saving method for pretreating lead paste of waste lead-acid batteries.

[0005] However, although the above-mentioned existing patents can solve the large investment and high cost in the treatment of waste lead-acid batteries, this method directly prepares lead paste by acid degassing, crushing and sorting the waste lead-acid batteries. The waste lead-acid batteries contain positive plates and negative plates. The positive plates are mainly lead dioxide, and the negative plates are mainly sponge lead. Therefore, the lead paste contained in the positive plates is greater than the lead paste contained in the negative plates. Under centralized treatment, the refining efficiency of the lead paste will be low. Summary of the invention

[0006] The purpose of the present application is to provide a method for pretreating lead paste of waste lead-acid batteries, so as to solve the problem of low efficiency of lead paste refining under existing centralized treatment.

[0007] The present invention separates the positive and negative plates of the waste lead-acid battery before pre-treating the lead paste, and performs classified extraction, so that the lead in the positive plate can be extracted to a greater extent, thereby improving the treatment efficiency of the lead paste and reducing the lead loss rate.

[0008] A method for pretreating lead paste of waste lead-acid batteries, comprising the following steps: S1, shelling: waste lead-acid batteries are collected by special environmentally friendly vehicles, and the collected waste lead-acid batteries are placed at fixed points, and the shells of the waste lead-acid batteries are centrally disassembled; S2, separation: after the waste lead-acid battery is shelled, the positive plate and the negative plate are separated, and then the separated positive plate and negative plate are cleaned; S3, crushing: prepare two crushing equipment and post the positive and negative plate labels on the surface of the crushing equipment; S4, pre-screening: placing the crushed positive electrode plate and negative electrode plate residues in clean water loaded in a transparent separation tank, respectively, and allowing the crushed positive electrode plate and negative electrode plate residues to stand in the clean water for about 1 hour; S5, deacidification: placing the lead metal in distilled water for cleaning; S6, sorting: sorting the lead-containing metal into metal parts and lead paste, and performing wet desulfurization on the lead paste, using a specific desulfurization agent during the desulfurization process; S7, pyrometallurgy: the metal parts and the desulfurized lead paste are put into pyrometallurgy; S8, molding: melt the lead paste into liquid, then skim off the metal foam on the surface, mix the lead liquid with caustic soda to refine it, inject the refined lead liquid into the mold, and scrape off the metal foam on the surface.

[0009] As a further improvement of the present invention, in step S1, the shell of the waste lead-acid battery is disassembled by tools, and the tools include a saw, a resistance wire, an open screwdriver, a hammer and a battery screwdriver. The saw is used to cut the heated resistance wire in the lead-acid battery, the screwdriver is used to align the seal of the lead-acid battery, and the hammer is used to hit the screwdriver to make the cover of the lead-acid battery fall off. In this way, the outer shell of the waste battery can be disassembled, and the positive plate and the negative plate in the battery can be separated.

[0010] As a further improvement of the present invention, in step S2, the positive plate and the negative plate are placed separately, and the outer sides of the positive plate and the negative plate are marked. Thus, the positive plate and the negative plate can be refined separately, and a large amount of lead paste in the positive plate can be extracted, thereby reducing the lead loss rate. At the same time, the positive plate and the negative plate are classified to prevent the positive plate from being mixed with the negative plate, thereby affecting the refining efficiency.

[0011] As a further improvement of the present invention, in step S3, the interior of the crushing device is designed to be a sealed structure, the rotation speed of the crushing mechanism in the crushing device is set to 800r / min, and the crushing device is used to crush the positive and negative plates after cleaning. Thus, the positive and negative plates can be crushed by the crushing mechanism, and at the same time, it is prevented that the crushed materials splash and are removed during the crushing process of the positive and negative plates, which is inconvenient to clean and cause pollution to the environment.

[0012] As a further improvement of the present invention, in step S4, the slag includes lead-containing metal and plastic, and the lead-containing metal and plastic have different densities. The standing still can make the plastic slowly float to the surface of the water, and the plastic floating on the surface is fished out, and the fished out plastic can be placed together with the shell removed in S1. Thus, the screened plastic fragments and the shell of the waste lead-acid battery can be placed together, and they can be processed, melted, and remade into a battery shell, thereby realizing the repeated recycling of resources, which is more energy-saving and environmentally friendly.

[0013] As a further improvement of the present invention, in step S5, the lead-containing metal needs to be continuously stirred during cleaning, and the stirring can increase the contact area between the lead-containing metal and the distilled water, and the increased contact area is used to improve the cleaning efficiency of the lead-containing metal. After the lead-containing metal is cleaned, the acidity and alkalinity of the cleaning liquid need to be detected, and the acidity and alkalinity of the cleaning liquid needs to be between 6.0 and 7.0, thereby improving the cleaning efficiency of the lead-containing metal.

[0014] As a further improvement of the present invention, in step S6, the pH value needs to be adjusted to a suitable value before the conversion reaction ends, and the value is used to affect the type and form of the conversion product. The conversion of the lead sulfate reaches 85% to 90%, and the desulfurization agent uses a soluble carbonate or a strong base. The desulfurization process requires a certain solid-liquid ratio, temperature, time and stirring speed. Thus, the lead paste is desulfurized by a soluble carbonate or a strong base, and the PbS04 in the lead paste can be converted into PbCO3, thereby achieving the desulfurization of the lead paste, wherein the solid-liquid ratio is 7, the conversion temperature is 45°C, the conversion time is 50min, and the stirring speed is 500r / min, so that the desulfurization reaction of PbS04 into PbCO3 is sufficient, and sulfate and PbCO3 or PbO2 conversion products are generated.

[0015] As a further improvement of the present invention, in step S7, the pyrometallurgy uses a reverberatory furnace, a rotary short furnace and a blast furnace, the smelting temperature is set between 300-400 degrees Celsius, the metal part and the desulfurized lead paste need to be stirred during the smelting, the auxiliary material for smelting uses a mineralizer, and the smelting time takes 10 hours. Thus, by adding auxiliary material minerals to assist combustion, the combustion efficiency is improved and the combustion is more complete.

[0016] As a further improvement of the present invention, in step S8, the lead liquid can be cooled and formed by continuously spraying ice water on the outside of the mold, and the molded lead block is demolded. Thus, the lead liquid can be hardened and formed within 4 minutes, thereby improving the preparation and molding efficiency of the lead liquid.

[0017] Compared with the prior art, the present invention has the following beneficial effects: After the lead paste is desulfurized, it enters the pyrometallurgical smelting process, which overcomes the shortcomings of high energy consumption, high metal volatilization loss, and high pollution emissions of pyrometallurgical regeneration smelting. By converting PbSO4 in the lead paste into soluble Na2SO4 and insoluble Pb2CO3 or Pb(OH)2 precipitation, it is easy to screen it out, thereby realizing the effective separation and recovery of the lead paste. The lead paste after desulfurization can be pyrometallurgically smelted at a lower temperature. This is because PbCO3 can be decomposed into PbO at 340℃, and the pyrometallurgical smelting temperature of the lead paste after desulfurization is usually more than 150℃ lower than that before desulfurization. The reduction in temperature helps to reduce energy consumption, thereby improving the overall efficiency and economy of the smelting process. In addition, the desulfurization process reduces the sulfur content in the lead paste, thereby reducing the emission of harmful gases such as SO2 during the pyrometallurgical smelting process. Desulfurization pretreatment also helps to reduce the amount of materials entering the furnace, making it easier to separate lead metal from the charge. The volatilization loss of lead in the smelting process of the lead paste after desulfurization is reduced, thereby improving the recovery rate of lead.

[0018] The temperature of pyrometallurgical regeneration smelting can be reduced. When the desulfurized lead paste is smelted by pyrometallurgy, the temperature required is 100-150 degrees Celsius lower than that of the undesulfurized lead paste, reducing problems such as high energy consumption, high metal volatilization loss and high pollution emissions, and realizing green and efficient lead recovery. Lowering the smelting temperature directly reduces energy consumption. Lower temperatures also mean less heat loss, which improves the energy efficiency of the entire smelting process. Moreover, the reduction in temperature helps to reduce the volatilization loss of lead metal during the smelting process, thereby increasing the recovery rate of lead, which not only increases economic benefits but also reduces the waste of resources. Lowering the smelting temperature also makes the smelting process more stable and controllable, which helps to improve production efficiency and product quality. In addition, lower smelting temperatures also reduce the thermal stress and wear of equipment, thereby extending the service life of the equipment.

[0019] Before pre-treating the lead paste, the positive and negative plates of the waste lead-acid battery are separated and extracted by classification, so that the lead in the positive plate can be extracted to a greater extent, thereby improving the treatment efficiency of the lead paste and reducing the loss rate of lead. The separation of the positive and negative plates makes the subsequent lead paste treatment more targeted, and different extraction strategies can be adopted according to the different components of the positive and negative plates, which also helps to extract the lead in the positive plate more efficiently, reducing the ineffective labor and time waste in the treatment process. Classification extraction can avoid the mutual interference or loss of useful components in the positive and negative plates during the mixed treatment process. By precisely controlling the treatment conditions, the lead in the positive plate can be retained to the greatest extent and its loss during the treatment process can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a flow chart of the steps of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Embodiment, a method for pretreating lead paste of waste lead-acid batteries, such as Figure 1 As shown, the following steps are included: S1, shelling: waste lead-acid batteries are collected by special environmentally friendly vehicles, and the collected waste lead-acid batteries are concentrated at fixed points, and the shells of waste lead-acid batteries are disassembled in a centralized manner. When disassembling the shells of waste lead-acid batteries, tools such as saws, resistance wires, open screwdrivers, hammers, and battery screwdrivers can be used. If the battery is not a maintenance-free lead-acid battery, you can use a saw to carefully saw it open or use a heated resistance wire. For ordinary types of batteries, you can first open the sealing plug to pour out the acid inside, then use an open screwdriver to aim at the seal, and slowly hit the screwdriver with a hammer, once in each of the four directions, and then open the lid. At the same time, the removed shells can be collected. The recycling and treatment of waste lead-acid battery shells is an important part of promoting sustainable development. By realizing the recycling of resources and reducing environmental pollution, it can contribute to the sustainable development of society.

[0024] S2, separation: After the waste lead-acid battery is shelled, its positive plate and negative plate are separated, and then the separated positive plate and negative plate are cleaned. The cleaned positive plate and negative plate are placed separately. During the separation and cleaning process, the positive plate and negative plate need to be marked on their outer sides. The mark can clearly indicate the identity of each plate, so that the staff can quickly and accurately identify it during the processing process to avoid confusion. With clear markings, the staff can operate more orderly when handling a large number of plates, thereby improving overall work efficiency.

[0025] S3, Crushing: Prepare two crushing devices, and post the positive and negative plate labels on the surface of the crushing devices. Put the cleaned positive and negative plates into the crushing devices for crushing. The interior of the crushing device is designed with a sealed structure, and the speed of the crushing mechanism in the crushing device is 800r / min. The high-speed rotating crushing mechanism of the crushing device can quickly and effectively crush the positive and negative plates, thereby improving the efficiency of the entire recycling process. The sealed structure design can prevent the dust and debris generated during the crushing process from leaking out, keep the working environment clean, and also help reduce the workload of subsequent cleaning work.

[0026] S4, pre-screening: the crushed positive plate and negative plate debris are placed in the clear water loaded in the transparent separation tank, and the positive plate and negative plate debris are allowed to stand in the clear water for about 1 hour. Due to the different densities of lead metal and plastic, the plastic contained in the debris will slowly float to the surface of the water, and then the screened plastic is taken out, and the taken out plastic fragments can be placed together with the shell of the waste lead-acid battery removed in step S1. The pre-screening step realizes the effective separation of plastic and lead metal through a simple physical method (static separation), avoiding subsequent complex chemical or physical treatment steps. Moreover, the screened plastic fragments and the waste lead-acid battery shell are uniformly treated, which can achieve the optimal allocation of resources, facilitate the subsequent resource recovery enterprises to classify and process according to different types of materials, and improve the recovery rate and reuse efficiency of resources.

[0027] S5, deacidification: Place the lead-containing metal in distilled water for cleaning, and during the cleaning process, continuously stir the lead-containing metal to increase the contact area between the lead-containing metal and the distilled water and the frequency of release, thereby improving the cleaning efficiency of the lead-containing metal. After cleaning, test the acidity and alkalinity of the cleaning solution. When the acidity and alkalinity of the cleaning solution is between 6.0-7.0, it is sufficient. When the pH value of the cleaning solution reaches the range of 6.0~7.0, it indicates that the acidic substances on the metal surface have been effectively neutralized. Through an effective deacidification step, the additional processing costs caused by residual acidic substances in subsequent processing steps can be reduced. At the same time, deacidification can also improve the quality of metal recovery, thereby increasing recovery benefits and reducing overall processing costs.

[0028] S6, sorting: sort the lead-containing metal into metal part and lead paste, and wet desulfurize the lead paste. Specific desulfurizers can be used in the desulfurization process. The pH value should be adjusted to a suitable value before the conversion reaction ends to affect the type and form of the conversion product. The conversion rate of lead sulfate can reach 85%~90%. The desulfurizer used in the desulfurization of lead paste can use soluble carbonate or strong alkali, such as Na2CO3 or NH4HCO3. During the desulfurization process, it is carried out at a certain solid-liquid ratio, temperature, time and stirring speed. By sorting the lead-containing metal into metal part and lead paste, the lead paste can be desulfurized more effectively and the interference of the metal part in the desulfurization process can be avoided. In the desulfurization process, by adjusting the pH value to a suitable value, the type and form of the conversion product can be affected. The appropriate pH value helps to generate desulfurization products that are easy to handle and recycle, while reducing the generation of by-products. When the conversion rate of lead sulfate reaches 85%~90%, it can be shown that the desulfurization process has high efficiency and quality.

[0029] S7, pyrometallurgy: the metal part and the desulfurized lead paste are put into pyrometallurgy. Pyrometallurgy can use professional furnaces such as reverberatory furnaces, rotary short furnaces and blast furnaces, and add auxiliary materials. The smelting temperature is between 300-400 degrees Celsius. When smelting the metal part and the desulfurized lead paste, it is necessary to stir them properly. The auxiliary materials can be selected from mineralizers, and the smelting is 10 hours. Through pyrometallurgy, the metal part and the desulfurized lead paste can be effectively converted into high-quality metal products. Adding mineralizers during the smelting process helps to lower the melting point, increase the reaction rate and improve the product quality. Appropriate smelting temperature and stirring conditions can also ensure that the metal elements are fully reduced and separated, and reduce the impurity content.

[0030] S8, molding: melt the lead paste into liquid by step S7, then skim off the metal foam on its surface, mix the lead liquid with caustic soda, and refine it, inject the refined lead liquid into the mold, and scrape off the metal foam on the surface. After the lead liquid is injected into the mold, ice water can be continuously sprayed on the outside of the mold, and after the lead liquid is hardened and formed, it can be demoulded. In the melting and refining process, by skimming off the metal foam and mixing with caustic soda, impurities such as copper, tin, antimony, etc. in the lead liquid can be effectively removed, thereby improving the purity of lead. Moreover, the physical properties of the lead product after refining and molding, such as hardness, toughness, ductility, etc., can be optimized, which can meet the application requirements of different fields, and the refined lead product has higher corrosion resistance and can maintain stable performance under harsh environments.

[0031] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for pretreating lead paste of waste lead-acid batteries, characterized in that: The specific steps include: S1, shelling: waste lead-acid batteries are collected by special environmentally friendly vehicles, and the collected waste lead-acid batteries are placed at fixed points, and the shells of the waste lead-acid batteries are centrally disassembled; S2, separation: after the waste lead-acid battery is shelled, the positive plate and the negative plate are separated, and then the separated positive plate and negative plate are cleaned; S3, crushing: prepare two crushing equipment and post the positive and negative plate labels on the surface of the crushing equipment; S4, pre-screening: placing the crushed positive electrode plate and negative electrode plate residues in clean water loaded in a transparent separation tank, respectively, and allowing the crushed positive electrode plate and negative electrode plate residues to stand in the clean water for about 1 hour; S5, deacidification: placing the lead metal in distilled water for cleaning; S6, sorting: sorting the lead-containing metal into metal parts and lead paste, and performing wet desulfurization on the lead paste, using a specific desulfurization agent during the desulfurization process; S7, pyrometallurgy: the metal parts and the desulfurized lead paste are put into pyrometallurgy; S8, molding: melt the lead paste into liquid, then skim off the metal foam on the surface, mix the lead liquid with caustic soda to refine it, inject the refined lead liquid into the mold, and scrape off the metal foam on the surface.

2. The method for pretreating lead paste of waste lead-acid batteries according to claim 1, characterized in that: In the step S1, the outer shell of the waste lead-acid battery is disassembled by tools, and the tools include a saw, a resistance wire, an open screwdriver, a hammer and a battery screwdriver. The saw is used to saw open the heated resistance wire in the lead-acid battery, the screwdriver is used to align with the sealing part of the lead-acid battery, and the hammer is used to hit the screwdriver to make the cover of the lead-acid battery fall off.

3. The method for pretreating lead paste of waste lead-acid batteries according to claim 1, characterized in that: In step S2, the positive electrode plate and the negative electrode plate are placed separately, and markings are made on the outside of the positive electrode plate and the negative electrode plate.

4. The method for pretreating lead paste of waste lead-acid batteries according to claim 1, characterized in that: In step S3, the interior of the crushing device is designed to be a sealed structure, the rotation speed of the crushing mechanism in the crushing device is set to 800 r / min, and the crushing device is used to crush the positive and negative plates after cleaning.

5. The method for pretreating lead paste of waste lead-acid batteries according to claim 1, characterized in that: In step S4, the debris includes lead-containing metal and plastic, and the lead-containing metal and plastic have different densities. The standing still can make the plastic slowly float to the surface of the water, and the plastic floating on the surface is fished out. The fished out plastic can be placed together with the shell removed in S1.

6. The method for pretreating lead paste of waste lead-acid batteries according to claim 1, characterized in that: In step S5, the lead-containing metal needs to be continuously stirred during cleaning. The stirring can increase the contact area between the lead-containing metal and distilled water. The increased contact area is used to improve the cleaning efficiency of the lead-containing metal. After the lead-containing metal is cleaned, the pH of the cleaning solution needs to be tested, and the pH of the cleaning solution needs to be between 6.0 and 7.

0.

7. The method for pretreating lead paste of waste lead-acid batteries according to claim 1, characterized in that: In step S6, the pH value needs to be adjusted to a suitable value before the conversion reaction ends. The value is used to affect the type and form of the conversion product. The conversion of the lead sulfate reaches 85% to 90%. The desulfurization agent uses a soluble carbonate or a strong base. The desulfurization process requires a certain solid-liquid ratio, temperature, time and stirring speed.

8. The method for pretreating lead paste of waste lead-acid batteries according to claim 7, characterized in that: In step S7, the pyrometallurgy uses a reverberatory furnace, a rotary short furnace and a blast furnace, the smelting temperature is set between 300-400 degrees Celsius, the metal part and the desulfurized lead paste need to be stirred during the smelting, the smelting auxiliary material uses a mineralizer, and the smelting time takes 10 hours.

9. The method for pretreating lead paste of waste lead-acid batteries according to claim 1, characterized in that: In step S8, the lead liquid can be cooled and formed by continuously spraying ice water on the outside of the mold, and the molded lead block is demolded.

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