A method for modifying and regenerating waste activated carbon and modified regenerated activated carbon

Abstract

This article discloses a method for modifying and regenerating waste activated carbon and modified regenerated activated carbon, the method comprising: chemically chelating, chemically modifying and heating the waste activated carbon for modification and regeneration in sequence to obtain modified regenerated activated carbon. The method of the present application can recover valuable metals in waste activated carbon through the step of chemical chelating; after recovery, the waste activated carbon is modified through the step of chemical modification, which can increase the specific surface area of ​​the waste activated carbon, increase its surface functional groups, and increase its polarity; and then through the step of heating modification and regeneration, most of the organic matter on the waste activated carbon can be decomposed and gasified, reducing carbon loss, while increasing the pore structure of the activated carbon, optimizing the adsorption performance of the activated carbon, thereby obtaining modified regenerated activated carbon with good performance.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of solid waste treatment technology, for example, a method for modifying and regenerating waste activated carbon and modified and regenerated activated carbon. Background Art

[0002] As a porous material, activated carbon has an extremely developed internal pore structure, a large specific surface area, and a strong adsorption capacity. It is used in many industrial production fields. For example, it is used in the wet recycling process of waste batteries. Activated carbon is often used to adsorb organic matter and trace heavy metals in the aqueous phase and / or gas phase.

[0003] At present, the price of activated carbon in the market is relatively high. The price of high-quality activated carbon exceeds 10,000 yuan / ton, and the price of coal-based activated carbon is generally not less than 3,000 yuan / ton. The amount of activated carbon used in the wet recycling process of batteries is large, and the cost of a single use of activated carbon is relatively high. In addition, since the discarded activated carbon in the wet recycling process of waste batteries is a hazardous waste, conventional landfill treatment is likely to cause secondary pollution and pose an environmental risk; if it is sent out for treatment, the cost of handling hazardous waste is high, which indirectly increases the operating cost of the wet process. At the same time, it will also cause the valuable metals in the discarded activated carbon to not be effectively utilized, resulting in a waste of resources. Therefore, the discarded activated carbon needs to be regenerated.

[0004] At present, the methods for regenerating waste activated carbon include heating regeneration, chemical regeneration, biological regeneration, ultrasonic and microwave regeneration. Among them, heating regeneration and chemical regeneration are the most widely used methods in the field of activated carbon regeneration in industry. However, for the waste activated carbon produced in the process of wet recycling of waste batteries, the single heating regeneration treatment cannot recover the valuable metals adsorbed by the waste activated carbon, resulting in a waste of resources. Moreover, the valuable metals that are not recovered will accumulate in the regenerated activated carbon in the form of ash, affecting the performance of the regenerated activated carbon. The single chemical regeneration treatment has poor versatility and can only regenerate a single substance. For example, in the literature (Yang Yanling, Regeneration of Powdered Activated Carbon by Solvent Regeneration [D], Tianjin University, 2014), methanol or ethanol is used alone to regenerate the waste activated carbon that adsorbs a single organic matter. However, the micropores are prone to collapse and blockage, the cycle regeneration rate is low, and multiple cycles will also cause ash accumulation, affecting the performance of the regenerated activated carbon.

[0005] In summary, it is an urgent problem to seek a process that can effectively regenerate the waste activated carbon in the process of wet recycling of waste batteries, with good regeneration performance and effective recovery of the valuable metals therein, which needs to be solved. Summary of the invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] The embodiment of the present application provides a method for modifying and regenerating waste activated carbon and modified regenerated activated carbon. The method of the present application can recover valuable metals in waste activated carbon through the step of chemical complexation; after recovery, the waste activated carbon is modified through the step of chemical modification, which can increase the specific surface area of ​​the waste activated carbon, increase its surface functional groups, and increase its polarity. Then, through the step of heating modification and regeneration, most of the organic matter on the waste activated carbon can be decomposed and gasified, reducing carbon loss, while increasing the pore structure of the activated carbon and optimizing the adsorption performance of the activated carbon, thereby obtaining modified regenerated activated carbon with good performance.

[0008] In a first aspect, an embodiment of the present application provides a method for modifying and regenerating waste activated carbon, the method comprising:

[0009] The waste activated carbon is subjected to chemical complexation, chemical modification and heating modification regeneration in sequence to obtain modified regenerated activated carbon.

[0010] The present application provides a method for modifying and regenerating waste activated carbon. Through the step of chemical complexation, valuable metals in the waste activated carbon can be recovered. After recovery, the waste activated carbon is modified through the step of chemical modification, which can increase the specific surface area of ​​the waste activated carbon, increase the types and quantity of its surface functional groups, and increase its polarity. Then, through the step of heating modification and regeneration, most of the organic matter on the waste activated carbon can be decomposed and gasified, reducing carbon loss, while increasing the pore structure of the activated carbon and optimizing the adsorption performance of the activated carbon, thereby obtaining modified and regenerated activated carbon with good performance.

[0011] Preferably, the waste activated carbon includes waste activated carbon produced in a wet process of recycling waste batteries; further, the waste activated carbon includes substantially adsorption-saturated activated carbon produced in a wet process of recycling waste batteries.

[0012] Preferably, the spent activated carbon is dry.

[0013] Preferably, the waste activated carbon includes valuable metal elements and / or ash.

[0014] Preferably, the valuable metal elements in the waste activated carbon include at least one of Ni, Co and Mn elements.

[0015] Preferably, based on the total mass of the waste activated carbon as 100%, the mass fraction of the valuable metal element is 0.5-3%, for example, it can be 0.5%, 0.7%, 1%, 1.5%, 2%, 2.5% or 3%.

[0016] Preferably, based on the total mass of the waste activated carbon as 100%, the mass fraction of the ash is 8-12%, for example, it can be 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5% or 12%, etc.

[0017] Preferably, the iodine adsorption value of the waste activated carbon is 90-200 mg / g, for example, it may be 90 mg / g, 100 mg / g, 120 mg / g, 150 mg / g, 170 mg / g or 200 mg / g.

[0018] Preferably, before the chemical complexation, the waste activated carbon is subjected to a physical cleaning process.

[0019] In the present application, a stage of physical cleaning can dissolve the free valuable metal salts and some organic matter entrained between the waste activated carbon or on the shallow surface in a solvent (such as water), thereby realizing the recovery and treatment of the valuable metal salts.

[0020] In the present application, after a stage of physical cleaning of the waste activated carbon, solid-liquid separation can be performed to obtain a stage of physically cleaned waste activated carbon and a stage of cleaning liquid containing valuable metals. The stage of cleaning liquid containing valuable metals can be recycled to recover the valuable metals.

[0021] Preferably, the physical cleaning step includes a first water immersion.

[0022] Preferably, during the first water immersion process, the mass ratio of waste activated carbon to water is 1:(10-50), for example, it can be 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, etc.

[0023] Preferably, the physical cleaning period lasts for 1-3 hours, for example, 1 hour, 1.2 hours, 1.5 hours, 1.7 hours, 2 hours, 2.2 hours, 2.5 hours, 2.7 hours or 3 hours.

[0024] Preferably, the specific step of the chemical complexing comprises: soaking the waste activated carbon in a chemical complexing liquid.

[0025] In the present application, after the waste activated carbon is immersed in the chemical complexing liquid for a period of time, the waste activated carbon after chemical complexing and the chemical complexing liquid containing valuable metals can be obtained through solid-liquid separation. The chemical complexing liquid containing valuable metals can be recycled to recover the valuable metals.

[0026] Preferably, the chemical complexing liquid comprises at least one of ammonia water, citric acid, ethylenediaminetetraacetic acid, acetic acid, formic acid and fruit acid.

[0027] In the present application, ammonia, citric acid, ethylenediaminetetraacetic acid, acetic acid, formic acid or fruit acid can acidify or complex the valuable metal salts adsorbed in the micropores of the waste activated carbon, desorb them from part of the organic matter, dissolve them in the chemical complexing liquid, and further recover the valuable metal salts.

[0028] Preferably, the amount of the chemical complexing liquid added is 0.2-1 times the theoretical amount required to complex the valuable metal elements in the waste activated carbon, for example, it can be 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.7 times, 0.9 times or 1 times, etc.

[0029] For example, if the chemical complexing liquid is ammonia water, ammonia water reacts with divalent nickel ions, Ni 2+ +6NH 3 .H 2 O=[Ni(NH 3 ) 6 ] 2+ +6H 2 O, for divalent nickel ions, theoretically, the amount of ammonia added is 6 times the amount of nickel ions. The same applies to the rest.

[0030] Preferably, the mass ratio of the waste activated carbon to the chemical complexing liquid is 1:(10-50), for example, it can be 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, etc.

[0031] Preferably, the chemical complexation time is 1-3 h, for example, 1 h, 1.2 h, 1.5 h, 1.7 h, 2 h, 2.2 h, 2.5 h, 2.7 h or 3 h.

[0032] Preferably, before the chemical modification, the waste activated carbon after chemical complexation is subjected to two-stage physical cleaning.

[0033] In the present application, the two-stage physical cleaning can clean and recover the free valuable metal salts and chemical complexing liquid on the surface of the waste activated carbon. Through the steps of the first-stage physical cleaning, chemical complexing and the second-stage physical cleaning, the valuable metals in the waste activated carbon can be fully and effectively recovered, and the ash content in the regenerated activated carbon can be effectively reduced.

[0034] In the present application, after the waste activated carbon is subjected to two-stage physical cleaning, solid-liquid separation can be performed to obtain the waste activated carbon after the two-stage physical cleaning and the two-stage cleaning liquid containing valuable metals. The two-stage cleaning liquid containing valuable metals can be recycled to recover the valuable metals.

[0035] Preferably, the second-stage physical cleaning method includes a second water immersion.

[0036] Preferably, during the second water immersion process, the mass ratio of waste activated carbon to water is 1:(10-50), for example, it can be 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, etc.

[0037] Preferably, the time of the second stage physical cleaning is 1-3 hours, for example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.7 hours, 2 hours, 2.2 hours, 2.5 hours, 2.7 hours or 3 hours.

[0038] Preferably, the specific step of chemical modification includes: soaking the chemically complexed waste activated carbon in a chemical modification liquid.

[0039] In the present application, after the waste activated carbon is immersed in the chemical modification liquid for a period of time, the chemically modified waste activated carbon and the used chemical modification liquid can be obtained through solid-liquid separation, and the used chemical modification liquid can be recycled.

[0040] Preferably, the chemical modification liquid comprises at least one of ammonia water, citric acid, ethylenediaminetetraacetic acid, acetic acid, formic acid and fruit acid.

[0041] In the present application, ammonia water, citric acid, ethylenediaminetetraacetic acid, acetic acid, formic acid or fruit acid, etc., can be used to chemically modify the waste activated carbon after chemical complexation, thereby increasing its specific surface area and increasing the surface functional groups of the waste activated carbon to increase its polarity.

[0042] In the present application, the types and concentrations of the components of the chemical modification liquid and the chemical complexing liquid may be the same or different, and there is no specific limitation on this, and there are many process options.

[0043] Preferably, the concentration of the chemical modification liquid is 0.02-0.2 mol / L, for example, it can be 0.02 mol / L, 0.04 mol / L, 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L or 0.2 mol / L, etc.

[0044] Preferably, the mass ratio of the waste activated carbon after chemical complexation to the chemically modified liquid is 1:(10-50), for example, it can be 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, etc.

[0045] Preferably, the chemical modification time is 1-3 h, for example, 1 h, 1.2 h, 1.5 h, 1.7 h, 2 h, 2.2 h, 2.5 h, 2.7 h or 3 h.

[0046] Preferably, before the heating modification and regeneration, the chemically modified waste activated carbon is subjected to three-stage physical cleaning and physical drying in sequence.

[0047] In the present application, three-stage physical cleaning can clean and recover excess chemical modification liquid on the surface of the waste activated carbon; physical drying can reduce the moisture content of the waste activated carbon and improve the heat utilization rate of the subsequent heating process.

[0048] Preferably, the three-stage physical cleaning method includes a third water immersion.

[0049] Preferably, during the third water immersion process, the mass ratio of the waste activated carbon to water is 1:(10-50), for example, it can be 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, etc.

[0050] Preferably, the time for the three stages of physical cleaning is 1-3 hours, for example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.7 hours, 2 hours, 2.2 hours, 2.5 hours, 2.7 hours or 3 hours.

[0051] Preferably, the moisture content of the waste activated carbon obtained after the physical drying is less than or equal to 15%, for example, it may be 15%, 12%, 10%, 8% or 6%.

[0052] Preferably, the specific steps of the heating modification and regeneration include: mixing the chemically modified waste activated carbon with the carbon material and performing heating regeneration.

[0053] In the present application, the heating modification and regeneration step can decompose and gasify most of the organic matter on the activated carbon, fully carbonize and activate the carbon material (such as asphalt and graphite), make up for the loss of activated carbon in the modification and regeneration process, reduce carbon loss, and at the same time increase the pore structure of the activated carbon and optimize the adsorption performance of the activated carbon.

[0054] Preferably, the carbon material includes pitch powder and graphite.

[0055] Preferably, the D50 particle size of the asphalt powder is 0.075-0.45 mm, for example, it may be 0.075 mm, 0.08 mm, 0.085 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm or 0.45 mm, etc.

[0056] Preferably, the D50 particle size of the graphite is 0.85-4 mm, for example, it may be 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm or 4 mm.

[0057] Preferably, the mass ratio of the asphalt powder to graphite is 1:(1-3), for example, it can be 1:1, 1:1.2, 1:1.5, 1:1.7, 1:2, 1:2.2, 1:2.5, 1:2.7 or 1:3, etc.

[0058] Preferably, based on the mass of the chemically modified waste activated carbon being 100%, the mass fraction of the asphalt powder is 1-8%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7% or 8%.

[0059] Preferably, based on the mass of the chemically modified waste activated carbon being 100%, the mass fraction of the graphite is 1-8%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7% or 8%.

[0060] Preferably, the heating regeneration is segmented heating regeneration, and the segmented heating regeneration includes: first performing a first stage of heating regeneration and then performing a second stage of heating regeneration.

[0061] Preferably, the temperature of the first stage heating regeneration is 300-700°C, for example, it can be 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C or 700°C.

[0062] Preferably, the atmosphere of the first stage heating regeneration is an inert atmosphere, and the gas in the inert atmosphere includes N 2 .

[0063] Preferably, the temperature of the second stage heating regeneration is 800-1000°C, for example, it can be 800°C, 850°C, 900°C, 950°C or 1000°C.

[0064] Preferably, the gas in the atmosphere of the second stage heating regeneration includes CO 2 .

[0065] In this application, the gas in the atmosphere of the second stage heating regeneration is adjusted to CO 2 The purpose is to regenerate the residual carbon in the activated carbon pores by using an activated gas (CO 2 , CO) for gasification to achieve the purpose of re-pore creation.

[0066] Preferably, the heating rate of the first stage heating regeneration and the heating rate of the second stage heating regeneration are independently 2-8°C / min, for example, they can be 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min or 8°C / min, etc.

[0067] Preferably, the heating regeneration time is 20-90 min, for example, it can be 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min or 90 min.

[0068] As a preferred technical solution of the present application, the method comprises:

[0069] S1, a physical cleaning stage: soaking the waste activated carbon in water for 1-3 hours, and then performing solid-liquid separation, wherein the waste activated carbon includes waste activated carbon generated in the process of wet recovery of waste batteries;

[0070] S2, chemical complexation: soak the waste activated carbon obtained after solid-liquid separation in step S1 in a chemical complexation liquid for 1-3 hours, and then perform solid-liquid separation;

[0071] S3, second stage physical cleaning: the waste activated carbon obtained after solid-liquid separation in step S2 is subjected to a second water immersion for 1-3 hours, and then solid-liquid separation is performed;

[0072] S4, chemical modification: soaking the waste activated carbon obtained after solid-liquid separation in step S3 in a chemical modification liquid for 1-3 hours, and then performing solid-liquid separation;

[0073] S5, three-stage physical cleaning: the waste activated carbon obtained after solid-liquid separation in step S4 is subjected to a third water immersion for 1-3 hours, and then solid-liquid separation is performed;

[0074] S6, physical drying: air-drying the waste activated carbon obtained after solid-liquid separation in step S5 until the moisture content of the waste activated carbon is less than or equal to 15%;

[0075] S7, heating modification and regeneration: the waste activated carbon after air drying in step S6 is mixed with asphalt powder and graphite, and heated and regenerated in stages to obtain modified regenerated activated carbon.

[0076] Preferably, in step S5, the waste activated carbon after the third water immersion is neutral.

[0077] Preferably, the air-drying temperature in step S6 is 20-40°C, for example, 20°C, 22°C, 25°C, 30°C, 35°C or 40°C.

[0078] Preferably, the modified regenerated activated carbon obtained in step S7 is cooled and dried for storage.

[0079] In a second aspect, an embodiment of the present application provides a modified regenerated activated carbon, which is prepared by the method for modifying and regenerating waste activated carbon described in the first aspect.

[0080] Preferably, the modified regenerated activated carbon includes valuable metal elements and / or ash.

[0081] Preferably, the valuable metal elements in the modified regenerated activated carbon include at least one of Ni, Co and Mn elements.

[0082] Preferably, based on the total mass of the modified regenerated activated carbon as 100%, the mass fraction of the valuable metal element is less than or equal to 0.2%, for example, it can be 0.2%, 0.19%, 0.18%, 0.15%, 0.12% or 0.1%, etc.

[0083] Preferably, based on the total mass of the modified regenerated activated carbon as 100%, the mass fraction of the ash is less than or equal to 5%, for example, it may be 5%, 4.8%, 4.5%, 4%, 3.5%, 3% or 2%.

[0084] Preferably, the iodine adsorption value of the modified regenerated activated carbon is greater than or equal to 800 mg / g, for example, it may be 800 mg / g, 820 mg / g, 850 mg / g, 900 mg / g, 920 mg / g, 950 mg / g or 980 mg / g.

[0085] Generally, the iodine adsorption value of fresh activated carbon is greater than or equal to 900 mg / g, and the iodine adsorption value of the modified regenerated activated carbon of the present application is relatively close to it, which indicates that the method of the present application can effectively modify and regenerate waste activated carbon, and the modified and regenerated activated carbon has good performance.

[0086] The numerical range described in this application includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to limited space and for the sake of brevity, this application no longer exhaustively lists the specific point values ​​included in the range.

[0087] Compared with the related art, the beneficial effects of the embodiments of the present application are:

[0088] (1) The present invention provides a method for modifying and regenerating waste activated carbon, which can effectively recover valuable metals in waste activated carbon through a chemical complexation step and effectively reduce the ash content in the regenerated activated carbon;

[0089] (2) In the method of the embodiment of the present application, after the valuable metals are recovered, the waste activated carbon is modified by a chemical modification step, which can increase the specific surface area of ​​the waste activated carbon, increase the types and number of its surface functional groups, increase its polarity, and reuse the chemical modification liquid to reduce resource waste;

[0090] (3) In the method of the embodiment of the present application, after chemical modification, most of the organic matter on the waste activated carbon can be decomposed and gasified by the step of heating modification and regeneration, and the added materials such as asphalt and graphite can make up for the carbon loss during the regeneration process, increase the pore structure of the activated carbon, and optimize the adsorption performance of the activated carbon;

[0091] (4) The method of the embodiment of the present application has loose processing conditions, and the reagents and auxiliary materials used are conventional and easily available, and no expensive equipment investment is required, so the cost is low and easy to promote;

[0092] (5) The method of the embodiment of the present application can effectively regenerate the waste activated carbon generated in the process of wet recycling of waste batteries, reduce the output of hazardous waste, and reduce the cost of treating solid waste residues in the process of wet recycling of waste batteries;

[0093] (6) The modified regenerated activated carbon prepared by the method of the embodiment of the present application has good regeneration performance. In the modified regenerated activated carbon, the mass fraction of valuable metal elements is less than or equal to 0.2%, and the mass fraction of ash is less than or equal to 5%; the iodine adsorption value of the modified regenerated activated carbon is greater than or equal to 800 mg / g.

[0094] Other aspects will be apparent upon reading and understanding the drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] The accompanying drawings are used to provide further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0096] Figure 1 A schematic flow chart of a method for modifying and regenerating waste activated carbon provided in one embodiment of the present application.

[0097] Figure 2 This is the SEM image of the modified regenerated activated carbon prepared in Example 1 of the present application.

[0098] Figure 3 This is the SEM image of the modified regenerated activated carbon prepared in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0099] The technical solution of the present application is further illustrated below through specific implementation methods.

[0100] In one embodiment, the present application provides a method for modifying and regenerating waste activated carbon, the process of which is as follows: Figure 1 As shown, specifically including:

[0101] S1. Perform a physical cleaning on the waste activated carbon, and after solid-liquid separation, obtain a section of waste activated carbon after physical cleaning and a section of cleaning liquid, and recover the section of cleaning liquid;

[0102] S2, chemically chelating the waste activated carbon after a stage of physical cleaning, and after solid-liquid separation, obtaining the waste activated carbon after chemical chelation and a chemical chelating liquid, and recovering the chemical chelating liquid;

[0103] S3, performing two-stage physical washing on the waste activated carbon after chemical complexation, and after solid-liquid separation, obtaining the waste activated carbon after the two-stage physical washing and the two-stage washing liquid, and recovering the two-stage washing liquid;

[0104] S4, chemically modifying the waste activated carbon after the second-stage physical cleaning, and obtaining chemically modified waste activated carbon and used chemically modified liquid after solid-liquid separation, wherein the used chemically modified liquid can be used for chemical modification again;

[0105] S5, performing three-stage physical washing on the chemically modified waste activated carbon, and after solid-liquid separation, obtaining the three-stage physically washed waste activated carbon;

[0106] S6, physically drying the waste activated carbon after the three-stage physical washing to obtain physically dried waste activated carbon;

[0107] S7, heating the physically dried waste activated carbon for modification and regeneration, and then cooling it to obtain modified regenerated carbon.

[0108] Example 1

[0109] This embodiment provides a method for modifying and regenerating waste activated carbon, comprising the following steps:

[0110] S1: Take 50g of waste activated carbon from the wet recycling process of waste batteries, soak it in 1000mL of water for 2h, then filter it, and recycle the obtained first cleaning liquid;

[0111] S2: The activated carbon obtained in S1 is placed in 500 mL of 0.025 mol / L citric acid solution and soaked for 1 hour, then filtered, and the obtained citric acid solution containing valuable metals is recovered;

[0112] S3: Soak the activated carbon obtained in step S2 in 1000 mL of water for 1 hour, then filter and recover the obtained second washing liquid;

[0113] S4: soaking the activated carbon obtained in step S3 in 500 mL of 0.075 mol / L ammonia solution for 1 h, then filtering, and recycling the obtained ammonia solution;

[0114] S5: Soak the activated carbon obtained in S4 in 1000 mL of water for 1 h, and then filter;

[0115] S6: The activated carbon obtained in S5 was naturally air-dried for 2 h, and the moisture content was 14%;

[0116] S7: The activated carbon obtained in step S6 is mixed with 3% of asphalt powder with a D50 particle size of 0.075mm-0.45mm and 5% of graphite with a D50 particle size of 0.85mm-4mm, and the mass ratio of asphalt powder to graphite is 1:1.7, and then placed in a high-temperature furnace for heating, modification and regeneration treatment, and the temperature is raised from room temperature to 450°C at a rate of 5°C / min, and the temperature is kept constant for 30 minutes, and N is introduced into the high-temperature furnace at the same time. 2 ; then increase the temperature from 450°C to 900°C at a rate of 5°C / min, while introducing CO into the high temperature furnace 2 , constant temperature heating for 1h;

[0117] S8: The activated carbon obtained in S7 is cooled, dried and stored to obtain modified regenerated activated carbon.

[0118] Example 2

[0119] This embodiment provides a method for modifying and regenerating waste activated carbon, comprising the following steps:

[0120] S1: Take 50g of waste activated carbon from the wet recovery process of waste batteries (the same as in Example 1), soak it in 1500mL of water for 2h, then filter it, and recover the obtained first cleaning liquid;

[0121] S2: The activated carbon obtained in S1 is placed in 1000 mL of 0.025 mol / L ethylenediaminetetraacetic acid solution and soaked for 1 hour, then filtered, and the obtained ethylenediaminetetraacetic acid solution containing valuable metals is recovered;

[0122] S3: Soak the activated carbon obtained in step S2 in 1500 mL of water for 1 hour, then filter and separate the solid and liquid, and recycle the second washing liquid;

[0123] S4: Soak the activated carbon obtained in step S3 in 1000 mL of 0.05 mol / L ammonia solution for 1.5 h, then filter and recycle the obtained ammonia solution;

[0124] S5: Soak the activated carbon obtained in S4 in 1500 mL of water for 1 h, and then filter;

[0125] S6: The activated carbon obtained in S5 was naturally air-dried for 3 hours, and the moisture content was 12%;

[0126] S7: The activated carbon obtained in step S6 is mixed with 5% of asphalt powder with a D50 particle size of 0.075mm-0.45mm and 7% of graphite with a D50 particle size of 0.85mm-4mm, and the mass ratio of asphalt powder to graphite is 1:1.4, and then placed in a high-temperature furnace for heating and regeneration treatment, and the temperature is raised from room temperature to 700°C at a rate of 6°C / min, and the temperature is kept constant for 40min, and N is introduced into the high-temperature furnace at the same time. 2 ; then increase the temperature from 700℃ to 900℃ at a rate of 4℃ / min, while introducing CO into the high temperature furnace 2 , constant temperature heating for 1.5h;

[0127] S8: The activated carbon obtained in S7 is cooled, dried and stored to obtain modified regenerated activated carbon.

[0128] Example 3

[0129] This embodiment provides a method for modifying and regenerating waste activated carbon, comprising the following steps:

[0130] S1: Take 50g of waste activated carbon from the wet recovery process of waste batteries (the same as in Example 1), soak it in 1500mL of water for 2h, then filter it, and recover the obtained first cleaning liquid;

[0131] S2: The activated carbon obtained in S1 is placed in 500 mL of 0.2 mol / L ammonia solution and soaked for 2 h, then filtered, and the obtained first regeneration liquid containing valuable metals is recovered;

[0132] S3: Soak the activated carbon obtained in step S2 in 1500 mL of water for 1 hour, then filter and recover the obtained second washing liquid;

[0133] S4: soaking the activated carbon obtained in step S3 in 500 mL of 0.1 mol / L acetic acid solution for 1.5 h, then filtering, and recycling the obtained second regeneration liquid;

[0134] S5: Soak the activated carbon obtained in S4 in 1500 mL of water for 1 h, and then filter;

[0135] S6: The activated carbon obtained in S5 was naturally air-dried for 2 h, and the moisture content was 14%;

[0136] S7: The activated carbon obtained in step S6 is mixed with 2% asphalt powder with a D50 particle size of 0.075mm-0.45mm and 5% graphite with a D50 particle size of 0.85mm-4mm, and the mass ratio of asphalt powder to graphite is 1:2.5, and then placed in a high-temperature furnace for heating and regeneration treatment, and the temperature is raised from room temperature to 300°C at a rate of 3°C / min, and the temperature is kept constant for 30min, while N is introduced into the high-temperature furnace. 2; then increase the temperature from 300°C to 800°C at a rate of 6°C / min, while introducing CO into the high temperature furnace 2 , constant temperature heating for 1h;

[0137] S8: The activated carbon obtained in S7 is cooled, dried and stored to obtain modified regenerated activated carbon.

[0138] Example 4

[0139] The difference between this embodiment and embodiment 1 is that asphalt powder and graphite are omitted in step S7, and the remaining parameters are exactly the same as those in embodiment 1.

[0140] Example 5

[0141] The difference between this embodiment and embodiment 1 is that in step S7, the asphalt powder and other masses are replaced by graphite, and the other parameters are exactly the same as those in embodiment 1.

[0142] Example 6

[0143] The difference between this embodiment and embodiment 1 is that in step S7, the graphite and other masses are replaced by asphalt powder, and the other parameters are exactly the same as those in embodiment 1.

[0144] Example 7

[0145] The difference between this embodiment and embodiment 1 is that in step S7, the mass fraction of the asphalt powder is adjusted to 8%, so that the mass ratio of the asphalt powder to graphite is adjusted to 1:0.625, and the other parameters are exactly the same as those in embodiment 1.

[0146] Example 8

[0147] The difference between this embodiment and embodiment 1 is that in step S7, the mass fraction of asphalt powder is adjusted to 1%, and the mass fraction of graphite is adjusted to 7%, so that the mass ratio of asphalt powder and graphite is adjusted to 1:7, and the other parameters are exactly the same as those in embodiment 1.

[0148] Example 9

[0149] This embodiment provides a method for modifying and regenerating waste activated carbon, comprising the following steps:

[0150] S1: Take 50g of waste activated carbon from the wet recycling process of waste batteries, soak it in 1000mL of water for 2h, and then filter the first washing liquid to recover it;

[0151] S2: The activated carbon obtained in S1 is placed in 500 mL of 0.025 mol / L citric acid solution and soaked for 1 hour, then filtered, and the obtained citric acid solution containing valuable metals is recovered;

[0152] S3: Soak the activated carbon obtained in step S2 in 1000 mL of water for 1 hour, then filter and recover the obtained second washing liquid;

[0153] S4: Soak the activated carbon obtained in step S3 in 500 mL of 0.025 mol / L citric acid solution for 2 h, then filter and recycle the obtained ammonia water;

[0154] S5: Soak the activated carbon obtained in S4 in 1000 mL of water for 1 h, and then filter;

[0155] S6: The activated carbon obtained in S5 was naturally air-dried for 2 h, and the moisture content was 14%;

[0156] S7: The activated carbon obtained in step S6 is mixed with 3% of asphalt powder with a D50 particle size of 0.075mm-0.45mm and 5% of graphite with a D50 particle size of 0.85mm-4mm, and the mass ratio of asphalt powder to graphite is 1:1.7, and then placed in a high-temperature furnace for heating, modification and regeneration treatment, and the temperature is raised from room temperature to 450°C at a rate of 5°C / min, and the temperature is kept constant for 30 minutes, and N is introduced into the high-temperature furnace at the same time. 2 ; then increase the temperature from 450°C to 900°C at a rate of 5°C / min, while introducing CO into the high temperature furnace 2 , constant temperature heating for 1h;

[0157] S8: The activated carbon obtained in S7 is cooled, dried and stored to obtain modified regenerated activated carbon.

[0158] Comparative Example 1

[0159] The difference between this comparative example and Example 1 is that steps S2 and S3 are omitted, and step S4 is replaced by "immersing the activated carbon obtained in S1 in 500mL of 0.05mol / L hydrochloric acid solution for 1h, then filtering, and recovering the obtained regenerated liquid containing valuable metals", and at the same time, asphalt powder and graphite are omitted, and the other parameters are exactly the same as those in Example 1.

[0160] Figure 2 and Figure 3 The SEM images of the modified regenerated activated carbon prepared in Example 1 and Comparative Example 1 are shown respectively. Figure 2 and Figure 3 It can be seen from the comparison that the number of micropores of the modified regenerated activated carbon prepared in this application is significantly greater than that of the regenerated activated carbon treated with hydrochloric acid, which indicates that the substances in the micropores of the waste carbon are effectively desorbed by the method of this application. Compared with the regenerated activated carbon treated with hydrochloric acid, the number of micropores of the modified regenerated activated carbon prepared in this application is greater, and the micropore diameter is larger, the pores are not completely transparent, the inner wall is rough, and the specific surface area of ​​the activated carbon is larger. This indicates that by the method of this application, the substances in the micropores are not only effectively desorbed, but also well modified.

[0161] Comparative Example 2

[0162] The difference between this comparative example and Example 1 is that steps S2 and S3 are omitted, and step S4 is replaced by "immersing the activated carbon obtained in S1 in 500 mL of 0.05 mol / L hydrochloric acid solution for 1 h, then filtering, and recovering the obtained regenerated liquid containing valuable metals", and the other parameters are exactly the same as those in Example 1.

[0163] The untreated waste activated carbon in Example 1, and the modified regenerated activated carbons of Examples 1-9 and Comparative Examples 1-2 were tested, including:

[0164] (1) Iodine adsorption value test

[0165] The test was carried out with reference to the national standard "GBT 12496.8-2015 Test method for wood activated carbon - Determination of iodine adsorption value".

[0166] (2) Valuable metal element content test

[0167] The preliminary sample treatment referred to the operating steps of the national standard "GBT 12496.19-2015 Test method for wood activated carbon - Determination of iron content". After the volume was fixed in a 100mL volumetric flask, the content of valuable metal elements in the solution was detected by inductively coupled plasma spectrometer (ICP).

[0168] (3) Ash content test

[0169] The test was carried out with reference to the national standard "GBT12496.3-1999 Determination of ash content of wood activated carbon".

[0170] The test results are shown in Table 1.

[0171] Table 1

[0172]

[0173] analyze:

[0174] From the results of Examples 1-3, it can be seen that the iodine adsorption value of the modified regenerated activated carbon of the present application can reach more than 800 mg / g, reflecting its good regeneration performance, and the content of valuable metal elements and ash is low, indicating that the method of the present application can not only effectively regenerate waste activated carbon, but also recover valuable metals and reduce the ash content.

[0175] From the results of Example 1 and Examples 4-6, it can be seen that in the heating modification regeneration step, asphalt powder and graphite can cooperate to supplement carbon loss, increase the specific surface area of ​​activated carbon, improve the iodine adsorption value of activated carbon, and increase the acquisition rate of activated carbon. If asphalt powder and graphite are not added or only one of them is added, the iodine adsorption value will be relatively low, and the metal content and ash content will be relatively high.

[0176] It can be seen from the results of Example 1 and Examples 7-8 that if the mass ratio of asphalt powder and graphite is too small or too large, it will lead to insufficient conversion and utilization of carbon materials, waste of resources, low carbon loss replenishment rate, introduction of new impurities, and easy clogging of pores, relatively low iodine adsorption value, and relatively high ash content.

[0177] From the results of Example 1 and Comparative Examples 1-2, it can be seen that compared with Example 1, Comparative Example 1 adds the same theoretical amount (0.48 times the theoretical amount) of hydrochloric acid as a chemical modification liquid, but does not perform the chemical complexation step, and omits asphalt powder and graphite, which will result in a relatively low iodine adsorption value of the regenerated activated carbon and a relatively high ash content in the regenerated activated carbon. Compared with Comparative Example 1, although Comparative Example 2 adds asphalt powder and graphite for heating modification and regeneration, the improvement of the regeneration performance of the activated carbon is limited.

[0178] The applicant declares that the above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Technical personnel in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technical personnel in the relevant technical field within the technical scope disclosed in the present application are within the protection scope and disclosure scope of the present application.

Claims

1. A method for modifying and regenerating waste activated carbon, comprising: The waste activated carbon is subjected to chemical complexation, chemical modification and heating modification and regeneration in sequence to obtain modified regenerated activated carbon; The waste activated carbon includes waste activated carbon produced in the process of wet recovery of waste batteries; The specific steps of the chemical complexation include: soaking the waste activated carbon in a chemical complexation liquid; The chemical complexing liquid includes a solution formed by at least one of ammonia water, ethylenediaminetetraacetic acid, acetic acid, formic acid and fruit acid; The specific steps of the chemical modification include: soaking the chemically complexed waste activated carbon in a chemical modification liquid; The chemical modification liquid includes a solution formed by at least one of ammonia water, ethylenediaminetetraacetic acid, acetic acid, formic acid and fruit acid; The specific steps of the heating modification and regeneration include: mixing the chemically modified waste activated carbon with the carbon material and performing heating regeneration; The carbon material includes pitch powder and graphite; Taking the mass of the chemically modified waste activated carbon as 100%, the mass fraction of the asphalt powder is 1-8%, and the mass fraction of the graphite is 1-8%; and the mass ratio of the asphalt powder to the graphite is 1:(1-3).

2. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The waste activated carbon includes valuable metal elements and / or ash.

3. The method for modifying and regenerating waste activated carbon according to claim 2, wherein: The valuable metal elements in the waste activated carbon include at least one of Ni, Co and Mn elements.

4. The method for modifying and regenerating waste activated carbon according to claim 2, wherein: Taking the total mass of the waste activated carbon as 100%, the mass fraction of the valuable metal elements is 0.5-3%.

5. The method for modifying and regenerating waste activated carbon according to claim 2, wherein: Taking the total mass of the waste activated carbon as 100%, the mass fraction of the ash is 8-12%.

6. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The iodine adsorption value of the waste activated carbon is 90-200 mg / g.

7. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: Prior to the chemical complexation, the spent activated carbon is subjected to a period of physical washing.

8. The method for modifying and regenerating waste activated carbon according to claim 7, wherein: The physical cleaning method includes a first water immersion.

9. The method for modifying and regenerating waste activated carbon according to claim 8, wherein: During the first water immersion process, the mass ratio of the waste activated carbon to water is 1:(10-50).

10. The method for modifying and regenerating waste activated carbon according to claim 7, wherein: The physical cleaning time is 1-3 hours.

11. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The fruit acid in the chemical complexing liquid is selected from citric acid.

12. The method for modifying and regenerating waste activated carbon according to claim 2, wherein: The amount of the chemical complexing liquid added is 0.2-1 times the theoretical amount required for complexing the valuable metal elements in the waste activated carbon.

13. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The mass ratio of the waste activated carbon to the chemical complexing liquid is 1:(10-50).

14. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The chemical complexation time is 1-3 hours.

15. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: Before the chemical modification, the waste activated carbon after chemical complexation is subjected to two-stage physical cleaning.

16. The method for modifying and regenerating waste activated carbon according to claim 15, wherein: The two-stage physical cleaning method includes a second water immersion.

17. The method for modifying and regenerating waste activated carbon according to claim 16, wherein: During the second water immersion process, the mass ratio of the waste activated carbon to water is 1:(10-50).

18. The method for modifying and regenerating waste activated carbon according to claim 15, wherein: The time of the second stage physical cleaning is 1-3 hours.

19. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The fruit acid in the chemical modification liquid is selected from citric acid.

20. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The concentration of the chemical modification liquid is 0.02-0.2 mol / L.

21. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The mass ratio of the waste activated carbon after chemical complexation to the chemically modified liquid is 1:(10-50).

22. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The time of the chemical modification is 1-3 hours.

23. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: Before the heating modification and regeneration, the chemically modified waste activated carbon is subjected to three-stage physical cleaning and physical drying in sequence.

24. The method for modifying and regenerating waste activated carbon according to claim 23, wherein: The three-stage physical cleaning method includes a third water immersion.

25. The method for modifying and regenerating waste activated carbon according to claim 24, wherein: During the third water immersion process, the mass ratio of the waste activated carbon to water is 1:(10-50).

26. The method for modifying and regenerating waste activated carbon according to claim 23, wherein: The time for the three stages of physical cleaning is 1-3 hours.

27. The method for modifying and regenerating waste activated carbon according to claim 23, wherein: The water content of the waste activated carbon obtained after the physical drying is less than or equal to 15%.

28. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The D50 particle size of the asphalt powder is 0.075-0.45 mm.

29. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The D50 particle size of the graphite is 0.85-4 mm.

30. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The heating regeneration is a segmented heating regeneration, and the segmented heating regeneration includes: first performing a first stage of heating regeneration, and then performing a second stage of heating regeneration.

31. The method for modifying and regenerating waste activated carbon according to claim 30, wherein: The temperature of the first stage heating regeneration is 300-700°C.

32. The method for modifying and regenerating waste activated carbon according to claim 30, wherein: The atmosphere of the first stage heating regeneration is an inert atmosphere, and the gas in the inert atmosphere includes N2.

33. The method for modifying and regenerating waste activated carbon according to claim 30, wherein: The temperature of the second stage heating regeneration is 800-1000°C.

34. The method for modifying and regenerating waste activated carbon according to claim 30, wherein: The gas in the atmosphere of the second-stage heating and regeneration includes CO2.

35. The method for modifying and regenerating waste activated carbon according to claim 30, wherein: The heating rate of the first stage heating regeneration and the heating rate of the second stage heating regeneration are independently 2-8°C / min.

36. The method for modifying and regenerating waste activated carbon according to claim 1, wherein: The heating regeneration time is 20-90min.

37. The method for modifying and regenerating waste activated carbon according to claim 1, comprising: S1, a physical cleaning stage: soaking the waste activated carbon in water for 1-3 hours, and then performing solid-liquid separation, wherein the waste activated carbon includes waste activated carbon generated in the process of wet recovery of waste batteries; S2, chemical complexation: soaking the waste activated carbon obtained after solid-liquid separation in step S1 in a chemical complexation liquid for 1-3 hours, and then performing solid-liquid separation; S3, second stage physical cleaning: the waste activated carbon obtained after solid-liquid separation in step S2 is subjected to a second water immersion for 1-3 hours, and then solid-liquid separation is performed; S4, chemical modification: soaking the waste activated carbon obtained after solid-liquid separation in step S3 in a chemical modification liquid for 1-3 hours, and then performing solid-liquid separation; S5, three-stage physical cleaning: the waste activated carbon obtained after solid-liquid separation in step S4 is subjected to a third water immersion for 1-3 hours, and then solid-liquid separation is performed; S6, physical drying: air-drying the waste activated carbon obtained after solid-liquid separation in step S5 until the moisture content of the waste activated carbon is less than or equal to 15%; S7, heating modification and regeneration: the waste activated carbon after air drying in step S6 is mixed with asphalt powder and graphite, and heated and regenerated in stages to obtain modified regenerated activated carbon.

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