Method for regenerating activated carbon, regenerated activated carbon and use thereof

Abstract

The application discloses a regeneration method of activated carbon, regenerated activated carbon and application thereof, and belongs to the technical field of activated carbon regeneration treatment. The regeneration method comprises the following steps: performing first regeneration on the activated carbon to be treated under the condition that an alkaline liquid and ozone coexist, so as to obtain first regenerated activated carbon from which part of adsorbents is removed; and performing second regeneration on the first regenerated activated carbon under the condition that an acid liquid and ozone coexist, so as to obtain regenerated activated carbon; wherein the adsorbents comprise at least one of an extractant and a diluent and a noble metal capable of catalyzing ozone. The method can effectively remove the adsorbents in the activated carbon to be treated, greatly restores the initial adsorption capacity of the activated carbon, and the obtained regenerated activated carbon can be recycled, which is favorable for reducing the cost and avoiding environmental pollution. The regenerated activated carbon can be used for removing oil components in raffinate.

Description

Technical Field

[0001] This invention relates to the field of activated carbon regeneration technology, and more specifically, to a method for regenerating activated carbon, regenerated activated carbon, and its applications. Background Technology

[0002] With the rapid development of the new energy vehicle industry, major battery material manufacturers and battery recycling companies have entered a phase of capacity expansion. To maximize the recovery of precious metals from spent power batteries, wet leaching combined with extraction and concentration methods are often employed. The wastewater generated during the extraction process, along with the remaining liquid after extraction, is collectively referred to as raffinate. In the recycling of ternary lithium-ion batteries, this raffinate contains a high amount of oil and organic matter due to the dissolution of a certain amount of extractant, diluent (such as sulfonated kerosene), and electrolyte. Furthermore, it also contains a certain amount of precious metals, such as nickel.

[0003] Current processes for treating the aforementioned raffinate primarily rely on evaporation. Before entering the evaporation equipment, the raffinate needs to be treated to remove oil and precious metals; otherwise, it will affect the operation of the evaporator. The oil components in the raffinate mainly include extractants (such as P204 and P507 extractants), diluents (such as sulfonated kerosene), saponified sodium salts, and trace amounts of extractant hydrolysis products and organometallic complexes. For the raffinate, since most of the oil exists in the form of dissolved oil, conventional methods such as oil separators, flotation, and demulsifiers are not ideal. Currently, the mainstream oil removal method is to use activated carbon adsorption tanks. However, activated carbon has a small oil adsorption capacity and easily reaches saturation. After adsorption saturation, it is directly treated as hazardous waste, which not only causes secondary pollution but also has high treatment costs. In addition, activated carbon also adsorbs a large amount of precious metals, such as nickel, resulting in direct waste and resource loss.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for regenerating activated carbon, as well as the regenerated activated carbon and its applications, in order to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows:

[0007] In a first aspect, the present invention provides a method for regenerating activated carbon, which includes the following steps: regenerating the activated carbon to be treated under the condition of the coexistence of alkaline liquid and ozone to obtain a first regenerated activated carbon with some adsorbents removed.

[0008] The first regenerated activated carbon is regenerated a second time under the conditions of acidic liquid and ozone to obtain regenerated activated carbon.

[0009] The adsorbents in the activated carbon to be treated include at least one of an extractant and a diluent, as well as a precious metal that can catalyze ozone.

[0010] In an optional embodiment, the extractant includes at least one of P204 extractant and P507 extractant; or, the diluent includes sulfonated kerosene.

[0011] In an optional embodiment, the adsorbent is the raffinate produced during the extraction process of recovering precious metals from waste power batteries using a wet leaching and extraction concentration method.

[0012] In an optional embodiment, the precious metal includes at least one of nickel, cobalt, and manganese.

[0013] In an optional embodiment, prior to the first regeneration, the activated carbon to be treated is further subjected to air washing in water containing air bubbles.

[0014] In an optional implementation, the air washing time is 10 min to 30 min.

[0015] In an alternative implementation, the bubbles are formed from air.

[0016] In an optional implementation, the air intake is 5m³. 3 / (m 2 (section h) ~ 15m 3 / (m 2 Cross section (h).

[0017] In an optional implementation, the bubbles are micron or nanometer-sized bubbles.

[0018] In an optional embodiment, the activated carbon after gas washing is in a loose state.

[0019] In an optional embodiment, the activated carbon after gas washing is backwashed with water to initially remove some of the adsorbents from the activated carbon to be treated.

[0020] In an optional implementation, the water backwashing time is 10 min to 30 min.

[0021] In an optional implementation, the volume of water used for backwashing is 2 to 4 times that of the activated carbon to be treated.

[0022] In an optional implementation, the alkaline liquid during the first regeneration process includes a sodium hydroxide solution.

[0023] In an optional embodiment, the concentration of sodium hydroxide in the sodium hydroxide solution is 3 wt% to 5 wt%.

[0024] In an optional implementation, during the first regeneration process, ozone acts on the activated carbon to be treated in the form of bubbles.

[0025] In an optional implementation, during the first regeneration process, ozone acts on the activated carbon to be treated in the form of micron or nanometer-sized bubbles.

[0026] In an optional implementation, during the first regeneration process, the ozone injection rate is 5m³. 3 / (m 2 (section h) ~ 15m 3 / (m 2 Cross section (h).

[0027] In an optional implementation, the first regeneration is carried out under conditions where the activated carbon to be treated is immersed in an alkaline liquid.

[0028] In an optional embodiment, the level of the alkaline liquid is at least 0.3 m above the top of the activated carbon to be treated.

[0029] In an optional implementation, the ozone exposure time during the first regeneration process is 2 to 4 hours.

[0030] In an optional embodiment, the method further includes: performing auxiliary regeneration of the first regenerated activated carbon under hot alkaline conditions to obtain intermediate regenerated activated carbon; and then performing a second regeneration of the intermediate regenerated activated carbon under conditions of acidic liquid and ozone to obtain regenerated activated carbon.

[0031] In an optional implementation, hot alkali is obtained by heating all the liquid in the container used in the first regeneration process after the first regeneration.

[0032] In an optional implementation, the hot alkali is obtained by heating all the liquid in the container with steam after the first regeneration.

[0033] In an optional embodiment, the temperature of the hot alkali is 60°C to 100°C.

[0034] In an optional implementation, the steam flow rate is 5m³. 3 / (m 2 (section h) ~ 10m 3 / (m 2 Cross section (h).

[0035] In an optional implementation, the steam action time is 1 to 2 hours.

[0036] In an optional embodiment, before the second regeneration, the intermediate regenerated activated carbon is further subjected to a first water backwash to remove residual alkaline liquid from the intermediate regenerated activated carbon.

[0037] In an optional implementation, the first water rinse ends when the pH of the rinsed liquid is <11.

[0038] In an optional implementation, the acidic liquid in the second regeneration process includes a sulfuric acid solution.

[0039] In an optional embodiment, the concentration of the sulfuric acid solution is 3 wt% to 5 wt%.

[0040] In an optional implementation, during the second regeneration process, ozone acts on the activated carbon to be treated in the form of bubbles.

[0041] In an optional implementation, during the second regeneration process, ozone acts on the activated carbon to be treated in the form of micron or nanometer-sized bubbles.

[0042] In an optional implementation, the ozone injection rate is 5m³. 3 / (m 2 (section h) ~ 15m 3 / (m 2 Cross section (h).

[0043] In an optional embodiment, the second regeneration is carried out under conditions where the activated carbon to be treated is immersed in an acidic liquid.

[0044] In an optional embodiment, the liquid level of the acidic liquid is at least 0.3 m above the top of the activated carbon to be treated;

[0045] In an optional implementation, the ozone exposure time during the second regeneration process is 1 to 2 hours.

[0046] In an optional embodiment, after the second regeneration, the method further includes: performing a second backwash of the regenerated activated carbon with water to remove any residual acidic liquid from the regenerated activated carbon.

[0047] In an optional implementation, the second water rinse ends when the pH value of the rinsed liquid is greater than 3.

[0048] Secondly, the present invention also provides regenerated activated carbon, which is obtained from activated carbon to be treated by the above-described regeneration method.

[0049] Thirdly, the present invention also provides an application of the above-mentioned regenerated activated carbon, such as using it to remove oil components from the raffinate.

[0050] In an optional embodiment, the raffinate is the raffinate generated during the extraction process of recovering precious metals from waste power batteries using a wet leaching and extraction concentration method.

[0051] In an optional embodiment, the oil components in the raffinate include at least one of the following: extractant, diluent, saponified sodium salt, extractant hydrolysis product, and organometallic complex.

[0052] In an optional embodiment, the extractant includes at least one of P204 extractant and P507 extractant.

[0053] In an optional implementation, the diluent includes sulfonated kerosene.

[0054] The beneficial effects of this invention include:

[0055] This invention involves the initial regeneration of activated carbon under alkaline liquid and ozone conditions. During this process, the sulfonated kerosene and extractant adsorbed in the activated carbon dissolve rapidly in the alkaline liquid. Furthermore, under alkaline conditions, the acidic functional groups on the activated carbon surface are neutralized by the alkaline substances, weakening the activated carbon's adsorption capacity. This facilitates the transfer of adsorbed substances such as sulfonated kerosene and extractant from the activated carbon to the alkaline liquid. In addition, the precious metals adsorbed by the activated carbon act as catalysts. Under the action of the metal catalyst, ozone generates hydroxyl radicals with stronger oxidizing power, oxidizing and decomposing the organic matter remaining in the activated carbon, breaking down large molecules into smaller molecules, and then converting the smaller molecules into carbon dioxide, thus playing a certain role in the regeneration of the activated carbon.

[0056] The second regeneration is carried out under the conditions of acidic liquid and ozone. During this process, the precious metals adsorbed in the activated carbon are soluble in the acidic liquid. Under the action of ozone, the organic matter in the remaining adsorbate can be oxidized, turning large organic molecules into small organic molecules, which are eventually removed from the activated carbon, thereby further reducing the organic matter content in the activated carbon. At the same time, under the action of ozone, the acid functional groups in the activated carbon can also be restored, enhancing the adsorption capacity of the activated carbon.

[0057] The activated carbon regeneration method described above can effectively remove the adsorbates adsorbed by the activated carbon to be treated, and restore the initial adsorption capacity of the activated carbon to a large extent. Attached Figure Description

[0058] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 A process flow diagram of the activated carbon regeneration method provided in an embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0061] The following is a detailed description of the activated carbon regeneration method provided by the present invention, as well as the regenerated activated carbon and its applications.

[0062] The present invention provides a method for regenerating activated carbon, which includes the following steps: regenerating the activated carbon to be treated under the condition of the coexistence of alkaline liquid and ozone to obtain first regenerated activated carbon with some adsorbents removed;

[0063] The first regenerated activated carbon is regenerated a second time under the conditions of acidic liquid and ozone to obtain regenerated activated carbon.

[0064] The adsorbents in the activated carbon to be treated include at least one of an extractant and a diluent, as well as a precious metal that can catalyze ozone.

[0065] The activated carbon to be treated can be activated carbon that exists independently of the container, or it can be activated carbon that is filled or placed in a container (including cans, bags, boxes, bottles, etc.).

[0066] The extractant in the activated carbon to be treated mainly includes at least one of P204 and P507 extractants, but may also include other types of extractants. The diluent may, but is not limited to, sulfonated kerosene. The precious metal may, but is not limited to, at least one of nickel, cobalt, and manganese. Furthermore, the adsorbent may also include saponified sodium salts and trace amounts of extractant hydrolysis products and organometallic complexes.

[0067] In some embodiments, the adsorbent in the activated carbon to be treated is the raffinate produced during the extraction process of recovering precious metals from spent power batteries using a wet leaching and extraction concentration method. This raffinate contains at least one of an extractant and a diluent, as well as precious metals. In addition, it may also contain saponified sodium salts, trace amounts of extractant hydrolysis products, and organometallic complexes.

[0068] Before the first regeneration, the present invention also includes air washing of the activated carbon to be treated in water containing air bubbles.

[0069] This process can wash and rub the surface and pores of the activated carbon to be treated, making the activated carbon loose, and at the same time washing the oil and other substances adsorbed on the surface of the activated carbon into the water. Through continuous collision, they gather into clumps and finally form oil droplets that float on the water surface.

[0070] In some implementations, the bubbles can be formed from air. The air flow rate can be 5m³. 3 / (m 2 (section h) ~ 15m 3 / (m 2 Cross section (h), such as 5m 3 / (m 2 (section h), 8m 3 / (m 2 (section h), 10m 3 / (m 2 (section h), 12m 3 / (m 2 (section h) or 15m 3 / (m 2 Cross section (h), etc. The "cross section" mentioned above refers to the cross section of the activated carbon to be treated, and the same applies below.

[0071] The bubbles used in the air washing process can be, for example, micron or nanometer-sized bubbles. By setting the bubbles to the micron or nanometer scale, bubbles of this size have a larger specific surface area, resulting in better scouring and friction effects. Furthermore, due to their smaller size, they are more likely to penetrate into the pores of the activated carbon to be treated and exert their effects.

[0072] For example, the air washing time can be 10 min to 30 min, such as 10 min, 15 min, 20 min, 25 min or 30 min, or any other value within the range of 10 min to 30 min.

[0073] In some optional embodiments, taking the activated carbon layer in the activated carbon adsorption tank as an example, the above-mentioned air washing process can be carried out as follows: Tap water is injected into the activated carbon adsorption tank saturated with oil, immersing the activated carbon layer in water. Pressurized air is then introduced into the titanium alloy aeration head at the bottom of the adsorption tank via an air compressor to form highly dispersed micron- or nano-sized bubbles. The water flow, carrying these micron- or nano-sized bubbles, washes and rubs the surface and pores of the activated carbon in the activated carbon layer, loosening the activated carbon layer. Simultaneously, the oil and other substances adsorbed on the activated carbon surface are washed into the water and aggregated through continuous collisions, eventually forming oil droplets that float on the water surface. The activated carbon adsorption tank can be, but is not limited to, the SLF-AC-1000 activated carbon filter from Zhonglan Environmental Protection Co., Ltd., and the titanium alloy aeration head can be, but is not limited to, the one from Yixing Hengye Environmental Protection Technology Co., Ltd. The microporous titanium alloy aerator provides compressed air. An exemplary, but not limited, air compressor, such as the EV-51 reciprocating air compressor from Guangdong Jaguar Industrial Equipment Co., Ltd., can be used.

[0074] After gas washing, the activated carbon obtained from gas washing can be backwashed with water to initially remove some of the adsorbents from the activated carbon to be treated.

[0075] In some optional implementations, taking the activated carbon to be treated as the activated carbon layer inside the activated carbon adsorption tank as an example, the above-mentioned water backwashing process can be carried out as follows: Tap water is introduced into the bottom of the activated carbon adsorption tank to displace floating oil and suspended solids from the top of the tank with the backwash water and discharge it from the activated carbon adsorption tank, so that the activated carbon adsorption tank can restore its flow rate. The discharged backwash wastewater (i.e., backwash water and floating oil and suspended solids discharged with it) enters the equalization tank and can be retreated later; after the water backwashing is completed, the drain valve at the bottom of the activated carbon adsorption tank is opened to drain the remaining water in the tank into the equalization tank.

[0076] The volume of water used for the backwash can be 2 to 4 times the volume of the activated carbon to be treated, such as 2, 2.5, 3, 3.5, or 4 times. The backwash time can be 10 to 30 minutes, such as 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes.

[0077] In this invention, the first regeneration process is also called the alkaline ozone regeneration process.

[0078] Similarly, ozone can also scour and rub the activated carbon during this process. The sulfonated kerosene and extractant adsorbed in the activated carbon can quickly dissolve in the alkaline liquid (if gas washing and water backwashing were performed beforehand, this process can dissolve most of the remaining sulfonated kerosene and extractant adsorbates in the alkaline water); furthermore, under alkaline conditions, the acidic functional groups on the surface of the activated carbon are neutralized by alkaline substances, weakening the adsorption performance of the activated carbon, which facilitates the transfer of the sulfonated kerosene and extractant adsorbed in the activated carbon to the alkaline liquid. In addition, the precious metals such as nickel, cobalt, and manganese adsorbed by the activated carbon can also act as catalysts. Under the action of these metal catalysts, ozone can generate hydroxyl radicals with stronger oxidizing power, oxidizing and decomposing the organic matter remaining in the activated carbon, converting large molecules into smaller molecules, and the smaller molecules into carbon dioxide, thus playing a certain role in the regeneration of the activated carbon. The ozone exhaust gas generated during the first regeneration process can be treated by an ozone destructor before being discharged.

[0079] The above-mentioned principles for the generation of hydroxyl radicals by ozone include:

[0080] first step: Me is a metal catalyst;

[0081] Step 2: O3+·O2 - →·O3 - +O2;

[0082] Step 3: O3 - +H₂O→·OH⁺OH — +O2;

[0083] Step 4: RX (organic matter) + ·OH → CO2 + H2O.

[0084] In this invention, the alkaline liquid used in the first regeneration process may include sodium hydroxide solution; in addition, other alkaline liquids may also be used.

[0085] In some embodiments, the concentration of sodium hydroxide in the sodium hydroxide solution can be 3wt% to 5wt%, such as 3wt%, 3.5wt%, 4wt%, 4.5wt%, or 5wt%. If the concentration of sodium hydroxide in the sodium hydroxide solution is too low, it will not be conducive to the dissolution and transfer of sulfonated kerosene and extractant adsorbed in the activated carbon into the sodium hydroxide solution; if the concentration of sodium hydroxide in the sodium hydroxide solution is too high, it will greatly increase the processing cost.

[0086] During the initial regeneration process, ozone primarily acts on the activated carbon in the form of bubbles. In some embodiments, ozone acts on the activated carbon in the form of micron- or nano-sized bubbles to achieve better results.

[0087] In the first regeneration process described above, the ozone injection rate can be 5m³.3 / (m 2 (section h) ~ 15m 3 / (m 2 Cross section (h), such as 5m 3 / (m 2 (section h), 8m 3 / (m 2 (section h), 10m 3 / (m 2 (section h), 12m 3 / (m 2 (section h) or 15m 3 / (m 2 (Cross section, h), etc. For example, the exposure time of ozone can be 2h to 4h, such as 2h, 2.5h, 3h, 3.5h or 4h, or any other value within the range of 2h to 4h.

[0088] In some embodiments, the first regeneration can be carried out with the activated carbon to be treated immersed in an alkaline liquid. Furthermore, the level of the alkaline liquid can be controlled to be at least 0.3 m above the top of the activated carbon to be treated to ensure optimal first regeneration results.

[0089] In some optional embodiments, taking the activated carbon to be treated as the activated carbon layer in the activated carbon adsorption tank as an example, the above-mentioned first regeneration process can be carried out as follows: A sodium hydroxide alkaline liquid with a mass fraction of 3wt% to 5wt% is introduced into the bottom of the activated carbon adsorption tank via a sodium hydroxide alkaline liquid dosing pump. When the alkaline liquid reaches 0.3m above the top of the activated carbon layer, the ozone generator is turned on, and ozone is introduced into the titanium alloy aeration head at the bottom of the tank. Through the action of the titanium alloy aeration head, highly dispersed micron- or nano-sized bubbles are formed, which scour and rub against the surface and pores of the activated carbon, thereby transferring the residual sulfonated kerosene, extractant, and other adsorbates in the activated carbon to the alkaline liquid. Furthermore, the precious metals such as nickel, cobalt, and manganese adsorbed in the activated carbon layer can act as catalysts for ozone, causing ozone to generate hydroxyl radicals with stronger oxidizing power, which oxidize and decompose the organic matter remaining in the activated carbon, thereby regenerating the activated carbon. The ozone generator described above can be, by way of example but not limitation, the CF-G-2-1Kg vertical integrated ozone generator of Qingdao Guolin Technology Group Co., Ltd.; the sodium hydroxide alkaline liquid dosing pump can be, by way of example but not limitation, the 25FSB-25 fluoroplastic centrifugal pump of Anhui Wolong Pump & Valve Co., Ltd.

[0090] In some embodiments, the first regenerated activated carbon can be regenerated under hot alkaline conditions to obtain intermediate regenerated activated carbon; then the intermediate regenerated activated carbon can be regenerated a second time under conditions of acidic liquid and ozone to obtain regenerated activated carbon.

[0091] Assisted regeneration facilitates the further thermal alkali dissolution of organic matter adsorbed inside activated carbon, and further transfers alkali-soluble substances such as extractants and sulfonated kerosene in the remaining adsorbents to the alkaline liquid, thereby improving the removal efficiency of these substances.

[0092] The aforementioned hot alkali is obtained by heating the liquid in the container used in the first regeneration process after the first regeneration. For example, it can be obtained by heating all the liquid in the container after the first regeneration with steam.

[0093] In some embodiments, the temperature of the hot alkali can be 60°C to 100°C, such as 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, or any other value within the range of 60°C to 100°C.

[0094] In some implementations, the steam flow rate can be 5m³. 3 / (m 2 (section h) ~ 10m 3 / (m 2 Cross section (h), such as 5m 3 / (m 2 (section h), 6m 3 / (m 2 (section h), 7m 3 / (m 2 (section h), 8m 3 / (m 2 (section h), 9m 3 / (m 2 (section h) or 10m 3 / (m 2 The cross-section (h) etc. The steam action time can be 1h to 2h, such as 1h, 1.5h or 2h, etc.

[0095] In some optional embodiments, taking the activated carbon to be treated as the activated carbon layer in the activated carbon adsorption tank as an example, the above-mentioned auxiliary regeneration process can be carried out as follows: Steam is introduced into the titanium alloy aeration head at the bottom of the tank after the first regeneration treatment to raise the water temperature in the tank to 60℃~100℃ for hot alkaline washing. Before introducing steam, ensure that the exhaust valve is open to prevent pressure buildup in the tank; after the hot alkaline washing is completed, open the drain valve at the bottom of the tank to discharge the liquid in the tank into the regeneration buffer tank as alkaline regeneration solution.

[0096] In some embodiments, prior to the second regeneration, the intermediate regenerated activated carbon is subjected to a first water backwash to remove any residual alkaline liquid from the intermediate regenerated activated carbon.

[0097] For example, the first water rinse ends when the pH of the rinsed liquid is <11.

[0098] The pH value detection involved in this invention can all be performed using an online pH meter. The online pH meter can be the SIN-pH type online pH meter from Hangzhou LianCe Automation Technology Co., Ltd., which is exemplary but not limited to it.

[0099] In some optional implementations, taking the activated carbon to be treated as the activated carbon layer in the activated carbon adsorption tank as an example, the first water backwash process can be carried out as follows: After the waste liquid is drained, the activated carbon adsorption tank is backwashed with tap water. Tap water is introduced into the upper part of the activated carbon adsorption tank to rinse away the residual alkaline liquid in the activated carbon until the pH value of the discharged water is <11. The backwash effluent flows into the equalization tank by gravity. After the backwash is completed, the drain valve is opened to drain the wastewater in the activated carbon adsorption tank.

[0100] In this invention, the second regeneration process is also called the acid ozone regeneration process.

[0101] Similarly, ozone can also scour and abrade the activated carbon during this process. The precious metals adsorbed in the first regenerated activated carbon are soluble in the acidic liquid used in the second regeneration process. Under the action of ozone, the organic matter in the remaining adsorbate can be oxidized, turning large organic molecules into smaller ones, which are then released from the activated carbon, further reducing its organic content. Simultaneously, ozone can also restore the acidic functional groups in the activated carbon, enhancing its adsorption capacity. The ozone exhaust gas generated during the second regeneration process can be treated by an ozone destructor before being discharged. After the second regeneration process is completed, the drain valve at the bottom of the tank can be opened to discharge the liquid into a regeneration buffer tank as an acidic regeneration solution.

[0102] To facilitate further differentiation, the working principle of ozone in the two regeneration processes is summarized as follows: In the first regeneration process, ozone decomposes to generate more oxidizing hydroxyl radicals, which oxidize and decompose the organic matter remaining in the activated carbon; in the second regeneration process, ozone uses its own oxidizing properties (ozone cannot generate hydroxyl radicals under acidic conditions) to degrade macromolecules into smaller molecules, which are then released from the pores of the activated carbon.

[0103] In this invention, the acidic liquid used in the second regeneration process may include sulfuric acid solution; in addition, other acidic liquids may also be used.

[0104] In some embodiments, the concentration of the sulfuric acid solution can be 3wt% to 5wt%, such as 3wt%, 3.5wt%, 4wt%, 4.5wt%, or 5wt%. If the concentration of the sulfuric acid solution is too low, it is not conducive to the leaching of precious metals adsorbed by activated carbon; if the concentration of the sulfuric acid solution is too high, it is not conducive to cost savings.

[0105] During the second regeneration process, ozone primarily acts on the activated carbon in the form of bubbles. In some embodiments, ozone acts on the activated carbon in the form of micron or nanometer-sized bubbles during the second regeneration process to achieve better results.

[0106] For example, the exposure time of ozone can be 1h to 2h, such as 1h, 1.5h or 2h, or any other value within the range of 1h to 2h.

[0107] When a second regeneration occurs directly after the first regeneration, the ozone in the second regeneration process mainly acts on the first regenerated activated carbon in the form of bubbles (such as micron or nanometer-sized bubbles). When there is an auxiliary regeneration process between the first and second regeneration, the ozone in the second regeneration process mainly acts on the intermediate regenerated activated carbon in the form of bubbles (such as micron or nanometer-sized bubbles).

[0108] In some embodiments, the second regeneration can be carried out with the activated carbon to be treated immersed in an acidic liquid. Furthermore, the level of the acidic liquid can be controlled to be at least 0.3 m above the top of the activated carbon to be treated to ensure optimal second regeneration results.

[0109] In some optional embodiments, taking the activated carbon to be treated as the activated carbon layer in the activated carbon adsorption tank as an example, the above-mentioned second regeneration process can be carried out as follows: A 3wt% to 5wt% acidic liquid (sulfuric acid solution) is injected into the tank using a sulfuric acid liquid dosing pump. When the sulfuric acid solution reaches 0.3m above the top of the activated carbon filter layer, the ozone generator is turned on, and ozone is introduced into the titanium alloy aeration head at the bottom of the tank. Highly dispersed micron- or nano-sized bubbles are formed through the titanium alloy aeration head, scouring and rubbing the surface and pores of the activated carbon. This causes the precious metals adsorbed in the activated carbon to dissolve in the acid. Under the action of the introduced ozone, the organic matter in the remaining adsorbate is oxidized, turning large organic molecules into small organic molecules, which are ultimately removed from the activated carbon. Simultaneously, under the action of ozone, the acid functional groups in the activated carbon are restored, enhancing the adsorption capacity of the activated carbon. The ozone destructor mentioned above can be, by way of example but not limitation, the DT150 exhaust gas destructor from Beijing Shanmei Shuimei Ozone High Technology Co., Ltd.; the sulfuric acid liquid dosing pump can be, by way of example but not limitation, the 25FSB-25 fluoroplastic centrifugal pump from Anhui Wolong Pump & Valve Co., Ltd.

[0110] After the second regeneration, the regenerated activated carbon can be subjected to a second water backwash to remove any residual acidic liquid.

[0111] For example, the second water rinse ends when the pH of the rinsed liquid is greater than 3.

[0112] In some optional implementations, taking the activated carbon to be treated as the activated carbon layer in the activated carbon adsorption tank as an example, the above-mentioned second water backwash process can be carried out as follows: After the waste liquid is drained, the activated carbon adsorption tank is backwashed with tap water. Tap water is introduced into the upper part of the activated carbon adsorption tank to rinse away the residual acidic liquid in the activated carbon until the pH value of the discharged water is >3. The backwash effluent flows into the equalization tank by gravity. After the backwash is completed, the drain valve is opened to drain the wastewater in the activated carbon adsorption tank.

[0113] In some embodiments, the acidic and alkaline regenerated solutions discharged into the regenerated solution buffer pool can be post-treated to recover the precious metals therein.

[0114] For example, acidic and alkaline regenerated solutions in the regenerated solution buffer tank are mixed to obtain a mixed regenerated solution. The pH value of the mixed regenerated solution is adjusted to 11-12, so that precious metals (such as nickel, cobalt, and manganese) in the mixed regenerated solution can precipitate in the form of hydroxides. After the precipitate is filtered dry by a filter press, the metal hydroxides can be recycled in the workshop.

[0115] In some embodiments, the pH of the mixed regenerated solution can be adjusted to 11-12 by adding liquid alkali (the concentration of liquid alkali can be 25wt% to 35wt%). The liquid alkali can be added using a liquid alkali dosing pump.

[0116] The aforementioned regenerated liquor buffer tank may be equipped with a stirrer, which is kept agitated during the mixing process. The regenerated liquor buffer tank may be made of PPH material, and the stirring paddle may be made of carbon steel lined with plastic.

[0117] For reference, the aforementioned mixer may, by way of example but not limitation, be the JBJ-900 paddle mixer from Nanjing Bihai Environmental Protection Equipment Co., Ltd.; the aforementioned filter press may, by way of example but not limitation, be the BJ15 / 630-30U plate and frame filter press from Shanghai Dazhang Filtration Equipment Co., Ltd.; and the aforementioned liquid alkali dosing pump may, by way of example but not limitation, be the 25FSB-25 fluoroplastic centrifugal pump from Anhui Wolong Pump & Valve Co., Ltd.

[0118] The above method can effectively regenerate the activated carbon to be treated and effectively recover the precious metals, especially nickel, adsorbed in the activated carbon.

[0119] Accordingly, the present invention also provides regenerated activated carbon, which is obtained from activated carbon to be treated by the above-described regeneration method.

[0120] This regenerated activated carbon can restore a high adsorption capacity and can be reused.

[0121] In addition, the present invention provides an application of the above-mentioned regenerated activated carbon, such as using it to remove oil components from the raffinate.

[0122] In some embodiments, the raffinate can be recovered from the extraction process of precious metals in waste power batteries by wet leaching followed by extraction and concentration.

[0123] The oil components in the above-mentioned raffinate may include, for example, at least one of the following: extractant, diluent, saponified sodium salt, extractant hydrolysis product, and organometallic complex.

[0124] The extractant may, by way of example but not limitation, include at least one of P204 extractant and P507 extractant. The diluent may, by way of example but not limitation, include sulfonated kerosene.

[0125] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0126] In the following examples and comparative examples, the activated carbon to be treated all came from the same activated carbon adsorption tank that had adsorbed oil in the raffinate treatment system (the raffinate generated during the extraction process of recovering precious metals from waste power batteries using a wet leaching and extraction concentration method). The raffinate contained extractants (including P204 and P507 extractants), diluents (including sulfonated kerosene), saponified sodium salts, and trace amounts of extractant hydrolysis products and organometallic complexes.

[0127] The activated carbon adsorption tanks in the following examples and comparative examples are all adsorption tanks where the adsorption capacity of the oil in the activated carbon layer is less than 10% of the original capacity and the nickel content is 3.77%.

[0128] Information on some of the instruments and equipment used in the following embodiments and comparative examples is as follows:

[0129] Activated carbon adsorption tank: uses SLF-AC-1000 activated carbon filter from Zhonglan Environmental Protection Co., Ltd.;

[0130] Titanium alloy aerator head: Used from Yixing Hengye Environmental Protection Technology Co., Ltd. Microporous titanium alloy aerator;

[0131] The compressed air compressor used is the EV-51 piston air compressor from Guangdong Jaguar Industrial Equipment Co., Ltd.

[0132] Ozone generator: The CF-G-2-1Kg vertical integrated ozone generator from Qingdao Guolin Technology Group Co., Ltd. is used.

[0133] Sodium hydroxide alkaline liquid dosing pump: Anhui Wolong Pump & Valve Co., Ltd.'s 25FSB-25 fluoroplastic centrifugal pump is used;

[0134] Ozone Destroyer: The DT150 exhaust gas destroyer from Beijing Shanmei Shuimei Ozone High Technology Co., Ltd. is used.

[0135] Sulfuric acid liquid dosing pump: Anhui Wolong Pump & Valve Co., Ltd.'s 25FSB-25 fluoroplastic centrifugal pump is used;

[0136] Mixer: JBJ-900 paddle mixer from Nanjing Bihai Environmental Protection Equipment Co., Ltd.

[0137] Filter press: Shanghai Dazhang Filtration Equipment Co., Ltd.'s BJ15 / 630-30U type plate and frame filter press is used;

[0138] Liquid alkali dosing pump: The 25FSB-25 fluoroplastic centrifugal pump from Anhui Wolong Pump & Valve Co., Ltd. is used.

[0139] Online pH meter: The SIN-pH online pH meter from Hangzhou LianCe Automation Technology Co., Ltd. is used.

[0140] Example 1

[0141] This embodiment provides a method for regenerating activated carbon. Please refer to [the relevant documentation]. Figure 1 This includes the following steps:

[0142] S1: Air washing.

[0143] Tap water is injected into the activated carbon adsorption tank saturated with oil, immersing the activated carbon layer. Pressurized air is then introduced into the titanium alloy aerator at the bottom of the tank via an air compressor, creating highly dispersed micron-sized bubbles. These bubbles, carried by the water flow, scour and rub against the surface and pores of the activated carbon, loosening the layer and washing away adsorbed oil and other substances. These substances collide and aggregate in the water, eventually forming oil droplets that float on the surface. The air flow rate is 10 m³ / h. 3 / (m 2 (Cross section h), air washing time is 20 min.

[0144] S2: Water backwash.

[0145] Tap water is introduced into the bottom of the activated carbon adsorption tank, displacing floating oil and suspended solids from the tank and draining them out with the backwash water, thus restoring the adsorption capacity. The discharged backwash wastewater enters the equalization tank. After the water backwash is complete, the drain valve at the bottom of the activated carbon adsorption tank is opened to drain the remaining water into the equalization tank. The volume of water used for backwashing is three times the volume of the activated carbon to be treated, and the backwashing time is 20 minutes.

[0146] S3: First regeneration process.

[0147] A 5wt% sodium hydroxide alkaline liquid is pumped into the bottom of the activated carbon adsorption tank using a sodium hydroxide alkaline liquid dosing pump. When the alkaline liquid reaches 0.3m above the top of the activated carbon layer, the ozone generator is activated, and ozone is introduced into the titanium alloy aerator at the bottom of the tank. The aerator creates highly dispersed micron-sized bubbles that scour and rub against the surface and pores of the activated carbon, transferring residual sulfonated kerosene, extractant, and other adsorbates to the alkaline liquid. The precious metals such as nickel, cobalt, and manganese adsorbed on the activated carbon layer act as catalysts for ozone, generating more potent hydroxyl radicals that oxidize and decompose the organic matter remaining in the activated carbon, thus regenerating the activated carbon and obtaining the first regenerated activated carbon. The ozone exhaust gas generated during the first regeneration process is treated by an ozone destroyer before being discharged. The ozone flow rate is 10m³. 3 / (m 2 The cross section (h) and the first regeneration time are 3 hours.

[0148] S4: Assisted regeneration.

[0149] Steam was introduced into the titanium alloy aerator at the bottom of the tank after the first regeneration treatment to raise the water temperature inside the tank to 80℃ for hot alkaline washing for 2 hours, yielding intermediate regenerated activated carbon. After the hot alkaline washing, the drain valve at the bottom of the tank was opened to discharge the liquid inside into the regeneration buffer tank as alkaline regeneration solution. The steam flow rate was 8m³ / min. 3 / (m 2 Cross section (h).

[0150] S5: First water rinse.

[0151] Perform a backwash of the activated carbon adsorption tank with tap water. Pour tap water into the top of the tank to rinse away any residual alkaline liquid from the activated carbon until the pH of the discharged water is <11. The backwash effluent flows by gravity into the equalization tank. After the backwash is complete, open the drain valve to empty the wastewater from the activated carbon adsorption tank.

[0152] S6: Second regeneration.

[0153] A 5 wt% sulfuric acid solution is injected into the tank using a sulfuric acid liquid dosing pump. When the sulfuric acid solution reaches 0.3 m above the top of the activated carbon filter layer, the ozone generator is turned on, and ozone is introduced into the titanium alloy aeration head at the bottom of the tank. The aeration head forms highly dispersed micron-sized bubbles, which scour and rub the surface and pores of the activated carbon, causing the adsorbed precious metals to dissolve in the acid. Under the action of the ozone, the organic matter in the remaining adsorbate is oxidized, turning large organic molecules into smaller ones, which are then removed from the activated carbon. Simultaneously, the ozone restores the acid functional groups in the activated carbon, enhancing its adsorption capacity, resulting in regenerated activated carbon. The ozone exhaust gas generated during the second regeneration process is treated by an ozone destroyer before being discharged. After the second regeneration process, the drain valve at the bottom of the tank is opened, and the liquid in the tank is discharged into the regeneration buffer tank as an acidic regeneration solution. The ozone injection rate is 10 m³ / s. 3 / (m 2 The cross section (h) and the second regeneration time are 2 hours.

[0154] S7: Second water rinse.

[0155] Perform a backwash of the activated carbon adsorption tank with tap water. Pour tap water into the top of the tank to rinse away any residual acidic liquid from the activated carbon until the pH of the discharged water is greater than 3. The backwash effluent flows by gravity into the equalization tank. After the backwash is complete, open the drain valve to empty the wastewater from the activated carbon adsorption tank.

[0156] S8: Recycling precious metals.

[0157] The acidic and alkaline regenerated solutions in the regenerated solution buffer tank are mixed to obtain a mixed regenerated solution. The pH value of the mixed regenerated solution is adjusted to 11-12 by adding 30wt% liquid alkali (measured by an online pH meter). The precious metals in the mixed regenerated solution precipitate in the form of hydroxides. After the precipitate is filtered dry by a filter press, the metal hydroxides are recovered.

[0158] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 87.86% of the original value, nickel metal recovery rate reaches 95.49%, and carbon loss is <1%.

[0159] Example 2

[0160] This embodiment provides a method for regenerating activated carbon, including the following steps:

[0161] S1: Air washing.

[0162] Tap water is injected into the activated carbon adsorption tank saturated with oil, immersing the activated carbon layer. Pressurized air is then introduced into the titanium alloy aerator at the bottom of the tank via an air compressor, creating highly dispersed micron-sized bubbles. These bubbles, carried by the water flow, scour and rub against the surface and pores of the activated carbon, loosening the layer and washing away adsorbed oil and other substances. These substances collide and aggregate in the water, eventually forming oil droplets that float on the surface. The air flow rate is 5 m³ / h. 3 / (m 2 (Cross section h), air washing time is 10 min.

[0163] S2: Water backwash.

[0164] Tap water is introduced into the bottom of the activated carbon adsorption tank, displacing floating oil and suspended solids from the top of the tank with the backwash water and discharging them out, thus restoring the adsorption capacity of the activated carbon adsorption tank. The discharged backwash wastewater enters the equalization tank. After the water backwash is completed, the drain valve at the bottom of the activated carbon adsorption tank is opened to drain the remaining water into the equalization tank. The volume of water used for backwashing is twice the volume of the activated carbon to be treated, and the backwashing time is 10 minutes.

[0165] S3: First regeneration process.

[0166] A 3wt% sodium hydroxide alkaline liquid is pumped into the bottom of the activated carbon adsorption tank using a sodium hydroxide alkaline liquid dosing pump. When the alkaline liquid reaches 0.2m above the top of the activated carbon layer, the ozone generator is activated, and ozone is introduced into the titanium alloy aerator at the bottom of the tank. The aerator creates highly dispersed micron-sized bubbles that scour and rub against the surface and pores of the activated carbon, transferring residual sulfonated kerosene, extractant, and other adsorbates to the alkaline liquid. The precious metals such as nickel, cobalt, and manganese adsorbed on the activated carbon layer act as catalysts for ozone, generating more potent hydroxyl radicals that oxidize and decompose the organic matter remaining in the activated carbon, thus regenerating the activated carbon and obtaining the first regenerated activated carbon. The ozone exhaust gas generated during the first regeneration process is treated by an ozone destroyer before being discharged. The ozone injection rate is 5m³ / s. 3 / (m 2 The cross section (h) and the first regeneration time are 2 hours.

[0167] S4: Assisted regeneration.

[0168] Steam was introduced into the titanium alloy aerator at the bottom of the tank after the first regeneration treatment to raise the water temperature inside the tank to 60℃ for hot alkaline washing for 1.5 hours, yielding intermediate regenerated activated carbon. After the hot alkaline washing, the drain valve at the bottom of the tank was opened to discharge the liquid inside into the regeneration buffer tank as alkaline regeneration solution. The steam flow rate was 5m³ / h. 3 / (m2 Cross section (h).

[0169] S5: First water rinse.

[0170] Perform a backwash of the activated carbon adsorption tank with tap water. Pour tap water into the top of the tank to rinse away any residual alkaline liquid from the activated carbon until the pH of the discharged water is <11. The backwash effluent flows by gravity into the equalization tank. After the backwash is complete, open the drain valve to empty the wastewater from the activated carbon adsorption tank.

[0171] S6: Second regeneration.

[0172] A 3wt% sulfuric acid solution is injected into the tank using a sulfuric acid liquid dosing pump. When the sulfuric acid solution reaches 0.2m above the top of the activated carbon filter layer, the ozone generator is turned on, and ozone is introduced into the titanium alloy aeration head at the bottom of the tank. The aeration head forms highly dispersed micron-sized bubbles, which scour and rub the surface and pores of the activated carbon, causing the adsorbed precious metals to dissolve in the acid. Under the action of the ozone, the organic matter in the remaining adsorbate is oxidized, turning large organic molecules into smaller ones, which are then removed from the activated carbon. Simultaneously, the ozone also restores the acid functional groups in the activated carbon, enhancing its adsorption capacity, resulting in regenerated activated carbon. The ozone exhaust gas generated during the second regeneration process is treated by an ozone destroyer before being discharged. After the second regeneration process, the drain valve at the bottom of the tank is opened, and the liquid in the tank is discharged into the regeneration liquid buffer tank as an acidic regeneration liquid. The ozone injection rate is 5m³. 3 / (m 2 The cross section (h) and the second regeneration time is 1 hour.

[0173] S7: Second water rinse.

[0174] Perform a backwash of the activated carbon adsorption tank with tap water. Pour tap water into the top of the tank to rinse away any residual acidic liquid from the activated carbon until the pH of the discharged water is greater than 3. The backwash effluent flows by gravity into the equalization tank. After the backwash is complete, open the drain valve to empty the wastewater from the activated carbon adsorption tank.

[0175] S8: Recycling precious metals.

[0176] The acidic and alkaline regenerated solutions in the regenerated solution buffer tank are mixed to obtain a mixed regenerated solution. The pH value of the mixed regenerated solution is adjusted to 11-12 by adding 25wt% liquid alkali (measured by an online pH meter). The precious metals in the mixed regenerated solution precipitate in the form of hydroxides. After the precipitate is filtered dry by a filter press, the metal hydroxides are recovered.

[0177] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 71.52% of the original value, nickel metal recovery rate reaches 78.69%, and carbon loss is <1%.

[0178] Example 3

[0179] This embodiment provides a method for regenerating activated carbon, including the following steps:

[0180] S1: Air washing.

[0181] Tap water is injected into the activated carbon adsorption tank saturated with oil, immersing the activated carbon layer. Pressurized air is then introduced into the titanium alloy aerator at the bottom of the tank via an air compressor, creating highly dispersed nano-sized bubbles. These bubbles, carried by the water flow, scour and rub against the surface and pores of the activated carbon, loosening the layer and washing away adsorbed oil and other substances. These substances collide and aggregate in the water, eventually forming oil droplets that float on the surface. The air flow rate is 15m³. 3 / (m 2 (Cross section h), air washing time is 30 min.

[0182] S2: Water backwash.

[0183] Tap water is introduced into the bottom of the activated carbon adsorption tank, displacing floating oil and suspended solids from the top of the tank with the backwash water and discharging them, thus restoring the adsorption capacity of the activated carbon adsorption tank. The discharged backwash wastewater enters the equalization tank. After the water backwash is completed, the drain valve at the bottom of the activated carbon adsorption tank is opened to drain the remaining water into the equalization tank. The volume of water used for backwashing is four times that of the activated carbon to be treated, and the backwashing time is 30 minutes.

[0184] S3: First regeneration process.

[0185] A 4 wt% sodium hydroxide alkaline liquid is pumped into the bottom of the activated carbon adsorption tank using a sodium hydroxide alkaline liquid dosing pump. When the alkaline liquid reaches 0.4 m above the top of the activated carbon layer, the ozone generator is activated, and ozone is introduced into the titanium alloy aerator at the bottom of the tank. The aerator creates highly dispersed nano-sized bubbles, which scour and rub the surface and pores of the activated carbon, transferring residual sulfonated kerosene, extractant, and other adsorbates to the alkaline liquid. The precious metals such as nickel, cobalt, and manganese adsorbed on the activated carbon layer act as catalysts for ozone, generating more potent hydroxyl radicals that oxidize and decompose the organic matter remaining in the activated carbon, thus regenerating the activated carbon and obtaining the first regenerated activated carbon. The ozone exhaust gas generated during the first regeneration process is treated by an ozone destroyer before being discharged. The ozone flow rate is 15 m³ / s. 3 / (m 2The cross section (h) and the first regeneration time are 4 hours.

[0186] S4: Assisted regeneration.

[0187] Steam was introduced into the titanium alloy aerator at the bottom of the tank after the first regeneration treatment to raise the water temperature inside the tank to 100℃ for hot alkaline washing for 1 hour, yielding intermediate regenerated activated carbon. After the hot alkaline washing, the drain valve at the bottom of the tank was opened to discharge the liquid inside into the regeneration buffer tank as alkaline regeneration solution. The steam flow rate was 10m³. 3 / (m 2 Cross section (h).

[0188] S5: First water rinse.

[0189] Perform a backwash of the activated carbon adsorption tank with tap water. Pour tap water into the top of the tank to rinse away any residual alkaline liquid from the activated carbon until the pH of the discharged water is <11. The backwash effluent flows by gravity into the equalization tank. After the backwash is complete, open the drain valve to empty the wastewater from the activated carbon adsorption tank.

[0190] S6: Second regeneration.

[0191] A 4wt% sulfuric acid solution is injected into the tank using a sulfuric acid liquid dosing pump. When the sulfuric acid solution reaches 0.4m above the top of the activated carbon filter layer, the ozone generator is turned on, and ozone is introduced into the titanium alloy aeration head at the bottom of the tank. The aeration head forms highly dispersed nano-sized bubbles, which scour and rub the surface and pores of the activated carbon, causing the adsorbed precious metals to dissolve in the acid. Under the action of the ozone, the organic matter in the remaining adsorbate is oxidized, turning large organic molecules into smaller ones, which are then removed from the activated carbon. Simultaneously, the ozone restores the acid functional groups in the activated carbon, enhancing its adsorption capacity, resulting in regenerated activated carbon. The ozone exhaust gas generated during the second regeneration process is treated by an ozone destroyer before being discharged. After the second regeneration process, the drain valve at the bottom of the tank is opened, and the liquid in the tank is discharged into the regeneration liquid buffer tank as an acidic regeneration liquid. The ozone injection rate is 15m³. 3 / (m 2 The second regeneration time is 1.5 hours (section h).

[0192] S7: Second water rinse.

[0193] Perform a backwash of the activated carbon adsorption tank with tap water. Pour tap water into the top of the tank to rinse away any residual acidic liquid from the activated carbon until the pH of the discharged water is greater than 3. The backwash effluent flows by gravity into the equalization tank. After the backwash is complete, open the drain valve to empty the wastewater from the activated carbon adsorption tank.

[0194] S8: Recycling precious metals.

[0195] The acidic and alkaline regenerated solutions in the regenerated solution buffer tank are mixed to obtain a mixed regenerated solution. The pH value of the mixed regenerated solution is adjusted to 11-12 by adding 35wt% liquid alkali (measured by an online pH meter). The precious metals in the mixed regenerated solution precipitate in the form of hydroxides. After the precipitate is filtered dry by a filter press, the metal hydroxides are recovered.

[0196] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 89.92% of the original value, nickel metal recovery rate reaches 91.23%, and carbon loss is <1%.

[0197] Example 4

[0198] The difference between this embodiment and Embodiment 1 is that there is no auxiliary regeneration process between the first regeneration process and the second regeneration process.

[0199] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 68.75% of the original value, nickel metal recovery rate reaches 92.94%, and carbon loss is <1%.

[0200] Comparative Example 1

[0201] This comparative example provides a method for regenerating activated carbon, including the following steps:

[0202] S1: Same as step S1 in Example 1.

[0203] S2: Same as step S2 in Example 1.

[0204] S3: Ozone regeneration.

[0205] After the activated carbon adsorption tank is emptied of waste liquid, tap water is added until it submerges the top of the activated carbon layer by 0.3m. Ozone is then introduced into the bottom titanium alloy aeration head at a flow rate of 10m³. 3 / (m 2 The ozone layer (section h) is used for ozone regeneration, which takes 3 hours. The ozone exhaust gas generated during this process is treated by an ozone destroyer before being discharged. After the ozone regeneration is completed, the drain valve at the bottom of the tank is opened to discharge the liquid in the tank into the regeneration liquid buffer tank as regeneration liquid.

[0206] S4: Recycling precious metals.

[0207] After ozone regeneration is completed, the pH of the regenerated liquid is adjusted to 11-12 by adding 30% liquid alkali. The agitator is kept stirring, and the precipitate is filtered dry by a filter press to recover the metal hydroxide.

[0208] The regenerated activated carbon obtained by the above regeneration method has an oil adsorption capacity restored to 32.43% of its original value, and the nickel metal recovery rate in the activated carbon is only 33.76%, with carbon loss <1%.

[0209] Comparative Example 2

[0210] This comparative example provides a method for regenerating activated carbon, including the following steps:

[0211] S1: Same as step S1 in Example 1.

[0212] S2: Same as step S2 in Example 1.

[0213] S3: Same as step S3 in Example 1.

[0214] S4: Same as step S4 in Example 1.

[0215] S5: Same as step S5 in Example 1.

[0216] S6: Recycling precious metals.

[0217] Add 30% liquid alkali to the regenerated liquid discharged from S4 to adjust its pH value to 11-12, keep the agitator stirring, and after the precipitate is filtered dry by a filter press, recover the metal hydroxide.

[0218] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 77.28% of the original value, nickel metal recovery rate reaches 20.62%, and carbon loss is <1%.

[0219] Comparative Example 3

[0220] The difference between this comparative example and Example 1 is that the first regeneration process in step S3 is carried out only in the presence of ozone, and no alkaline liquid is used in this process.

[0221] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 57.12% of the original value, nickel metal recovery rate reaches 85.09%, and carbon loss is <1%.

[0222] Comparative Example 4

[0223] The difference between this comparative example and Example 1 is that the first regeneration process in step S3 is carried out only in the presence of an alkaline liquid, and ozone is not used in this process.

[0224] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 49.77% of the original value, nickel metal recovery rate reaches 80.89%, and carbon loss is <1%.

[0225] Comparative Example 5

[0226] The difference between this comparative example and Example 1 is that the second regeneration process in step S6 is carried out only in the presence of an acidic liquid, and ozone is not used in this process.

[0227] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 79.81% of the original value, nickel metal recovery rate reaches 66.47%, and carbon loss is <1%.

[0228] Comparative Example 6

[0229] The difference between this comparative example and Example 1 is that the second regeneration process in step S6 is carried out only in the presence of ozone, and no acidic liquid is used in this process.

[0230] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 87.88% of the original value, nickel metal recovery rate reaches 29.47%, and carbon loss is <1%.

[0231] Comparative Example 7

[0232] The difference between this comparative example and Example 1 is that steps S3, S4, and S5 were not performed.

[0233] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 26.16% of the original value, nickel metal recovery rate reaches 76.61%, and carbon loss is <1%.

[0234] Comparative Example 8

[0235] The difference between this comparative example and Example 1 is that the activated carbon saturated with adsorbed oil is placed in a regeneration kiln, the temperature inside the kiln is controlled at 500°C, and the regeneration time is 2 hours.

[0236] The regenerated activated carbon obtained by the above regeneration method has its oil adsorption capacity restored to 91.82% of the original value, the nickel metal recovery rate is 0%, and the carbon loss is 13.68%.

[0237] For ease of comparison, the data of Examples 1-4 and Comparative Examples 1-8 are summarized in Table 1.

[0238] Table 1 Data Comparison Table

[0239] Example 1 87.86％ 95.49％ ＜1％ Example 2 71.52％ 78.69％ ＜1％ Example 3 89.82％ 91.23％ ＜1％ Example 4 68.75％ 92.94％ ＜1％ Comparative Example 1 32.43％ 33.76％ ＜1％ Comparative Example 2 77.28％ 20.62％ ＜1％ Comparative Example 3 57.12％ 85.09％ ＜1％ Comparative Example 4 49.77％ 80.89％ ＜1％ Comparative Example 5 79.81％ 66.47％ ＜1％ Comparative Example 6 87.88％ 29.47％ ＜1％ Comparative Example 7 26.16％ 76.61％ ＜1％ Comparative Example 8 91.82％ 0％ 13.68％

[0240] As can be seen from Table 1, the activated carbon regeneration method provided by the present invention can not only effectively remove the adsorbents adsorbed by the activated carbon to be treated and restore the initial adsorption capacity of activated carbon for oil to a large extent, but also has a high recovery rate of nickel metal adsorbed in activated carbon and carbon loss of less than 1%, which has high promotion value.

[0241] In summary, the activated carbon regeneration method provided by this invention can effectively remove adsorbates adsorbed by the activated carbon to be treated, and largely restore the initial adsorption capacity of the activated carbon for oil. The resulting regenerated activated carbon can be recycled, which helps to reduce costs. In addition, it can reduce the generation of hazardous waste and avoid environmental pollution. Furthermore, this method can effectively recover precious metals, especially nickel, adsorbed in the activated carbon to be treated, with a high nickel recovery rate.

[0242] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for regenerating activated carbon, characterized in that, Includes the following steps: The activated carbon to be treated is regenerated for the first time under the condition of alkaline liquid and ozone, to obtain the first regenerated activated carbon with some adsorbents removed. The first regenerated activated carbon is regenerated a second time under the conditions of acidic liquid and ozone to obtain regenerated activated carbon. The adsorbent in the activated carbon to be treated includes at least one of an extractant and a diluent, as well as a metal that can catalyze ozone; the metal includes at least one of nickel, cobalt, and manganese. The first regenerated activated carbon is regenerated under hot alkaline conditions to obtain intermediate regenerated activated carbon; the intermediate regenerated activated carbon is then regenerated a second time under conditions of acidic liquid and ozone to obtain regenerated activated carbon. Before the second regeneration, the process also includes: performing a first water backwash on the intermediate regenerated activated carbon to remove the residual alkaline liquid in the intermediate regenerated activated carbon; After the second regeneration, the process also includes: performing a second water backwash on the regenerated activated carbon to remove any residual acidic liquid from the regenerated activated carbon.

2. The regeneration method according to claim 1, characterized in that, The extractant includes at least one of P204 extractant and P507 extractant; or, the diluent includes sulfonated kerosene.

3. The regeneration method according to claim 1, characterized in that, The adsorbate is the raffinate produced during the extraction process of recovering precious metals from waste power batteries using a wet leaching and extraction concentration method.

4. The regeneration method according to claim 1, characterized in that, Before the first regeneration, the activated carbon to be treated is also air-washed in water containing air bubbles.

5. The regeneration method according to claim 4, characterized in that, The air washing time is 10 min to 30 min.

6. The regeneration method according to claim 4, characterized in that, Bubbles are formed from air.

7. The regeneration method according to claim 6, characterized in that, The air intake is 5m³. 3 / (m 2 (section h) ~15m 3 / (m 2 Cross section (h).

8. The regeneration method according to claim 4, characterized in that, The bubbles are at the micrometer or nanometer scale.

9. The regeneration method according to claim 4, characterized in that, The activated carbon after air washing is in a loose state.

10. The regeneration method according to claim 4, characterized in that, The activated carbon after air washing is backwashed with water to initially remove some of the adsorbents from the activated carbon to be treated.

11. The regeneration method according to claim 10, characterized in that, The water backwashing time is 10 to 30 minutes.

12. The regeneration method according to claim 10, characterized in that, The volume of water used for backwashing is 2 to 4 times that of the activated carbon to be treated.

13. The regeneration method according to claim 1, characterized in that, The first regeneration includes at least one of the following characteristics: Feature 1: The alkaline liquid includes a sodium hydroxide solution; Feature 2: Ozone acts on the activated carbon to be treated in the form of bubbles; Feature 3: The first regeneration is carried out under the condition that the activated carbon to be treated is immersed in the alkaline liquid; Feature 4: The duration of ozone exposure is 2 to 4 hours.

14. The regeneration method according to claim 13, characterized in that, The concentration of sodium hydroxide in the sodium hydroxide solution is 3wt%~5wt%.

15. The regeneration method according to claim 13, characterized in that, Ozone acts on the activated carbon to be treated as micron or nano-sized bubbles.

16. The regeneration method according to claim 13, characterized in that, The ozone injection rate is 5m³. 3 / (m 2 (section h) ~15m 3 / (m 2 Cross section (h).

17. The regeneration method according to claim 13, characterized in that, The alkaline liquid level is at least 0.3m above the top of the activated carbon to be treated.

18. The regeneration method according to claim 1, characterized in that, The hot alkali is obtained by heating all the liquid in the container used in the first regeneration process after the first regeneration.

19. The regeneration method according to claim 18, characterized in that, The hot alkali is obtained by heating all the liquid in the container used in the first regeneration process by introducing steam into the titanium alloy aerator at the bottom of the tank after the first regeneration process.

20. The regeneration method according to claim 19, characterized in that, The temperature of hot alkali is 60℃~100℃.

21. The regeneration method according to claim 19, characterized in that, The steam flow rate is 5m³. 3 / (m 2 (section h) ~10m 3 / (m 2 Cross section (h).

22. The regeneration method according to claim 19, characterized in that, The steam treatment time is 1 to 2 hours.

23. The regeneration method according to claim 1, characterized in that, The first water rinse ends when the pH value of the rinsed liquid is less than 11.

24. The regeneration method according to claim 1, characterized in that, The second regeneration includes at least one of the following characteristics: Feature 1: The acidic liquid includes a sulfuric acid solution; Feature 2: Ozone acts on the activated carbon to be treated in the form of bubbles; Feature 3: The second regeneration is carried out under conditions where the activated carbon to be treated is immersed in an acidic liquid; Feature 4: The duration of ozone exposure is 1 to 2 hours.

25. The regeneration method according to claim 24, characterized in that, The concentration of the sulfuric acid solution is 3wt%~5wt%.

26. The regeneration method according to claim 24, characterized in that, Ozone acts on the activated carbon to be treated as micron or nano-sized bubbles.

27. The regeneration method according to claim 26, characterized in that, The ozone injection rate is 5m³. 3 / (m 2 (section h) ~15m 3 / (m 2 Cross section (h).

28. The regeneration method according to claim 24, characterized in that, The level of the acidic liquid is at least 0.3m above the top of the activated carbon to be treated.

29. The regeneration method according to claim 1, characterized in that, The second water rinse ends when the pH value of the rinsed liquid is greater than 3.

30. A type of regenerated activated carbon, characterized in that, The regenerated activated carbon is obtained from the activated carbon to be treated by the regeneration method described in any one of claims 1 to 29.

31. An application of the regenerated activated carbon as described in claim 30, characterized in that, The regenerated activated carbon is used to remove oil components from the raffinate.

32. The application according to claim 31, characterized in that, The raffinate is the raffinate produced during the extraction process of recovering precious metals from waste power batteries using a wet leaching and extraction concentration method.

33. The application according to claim 32, characterized in that, The oil components in the raffinate include at least one of the following: extractant, diluent, saponified sodium salt, extractant hydrolysis product, and organometallic complex.

34. The application according to claim 33, characterized in that, The extractant includes at least one of P204 extractant and P507 extractant.

35. The application according to claim 33, characterized in that, The diluent includes sulfonated kerosene.

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