Electrolyte anode scrap treatment method
Through ultrasonic enhanced alkaline leaching treatment and separation technology, the problems of low fluorine/sodium recovery rate and poor carbon powder purity in the electrolyte residual anode were solved, efficient fluorine and sodium recovery and carbon powder purification were achieved, and the equipment and current efficiency of the electrolysis process were improved.
Patent Information
- Application Number
- CN202510922927.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-04
- Publication Date
- 2025-10-14
AI Technical Summary
In the existing technology, the fluorine/sodium recovery rate of the electrolyte residual anode is low and the carbon powder purity is poor, which leads to problems such as equipment corrosion, reduced current efficiency and poor electrolyte fluidity.
Ultrasonic enhanced technology is used for alkaline leaching treatment. The carbon layer is broken by ultrasonic cavitation effect, and the leachate and leach residue are separated by combining with sodium hydroxide solution. The leachate is then treated with calcium chloride solution to separate calcium fluoride and sodium-containing solution, and high-purity calcium fluoride and sodium fluoride are obtained by evaporation and crystallization.
It significantly improves the leaching rates of fluorine and sodium, enhances the purity and recovery efficiency of carbon powder, reduces the risk of equipment corrosion, and improves the current efficiency and electrolyte fluidity of the electrolysis process.
Smart Images
Figure CN120774404A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of nonferrous metal metallurgy and resource recovery, and in particular to a method for treating electrolyte residual anodes. Background Art
[0002] With the continued expansion of my country's electrolytic aluminum production capacity, the industry's annual output is expected to exceed 43 million tons in 2024. In addition to spent cathode carbon blocks, electrolytic cell operation also produces a large amount of scrap anode material containing fluorine and sodium compounds. Statistics show that every ton of aluminum produced generates 22-32 kg of scrap anode material, primarily composed of a carbon matrix (50-65 wt%), sodium fluoride (0.5-8 wt%), aluminum fluoride (2-10 wt%), and trace amounts of cyanide.
[0003] Existing technologies usually use landfill, pyrolysis and wet leaching as treatment methods, but the landfill method will cause fluoride to seep into the groundwater system, causing soil and water pollution, and it is impossible to achieve resource recycling. Pyrolysis has high energy consumption (>1200℃) and is prone to produce harmful gases such as HF, posing a threat to the environment and the health of operators. Conventional wet leaching has an extraction rate of less than 60% for sodium fluoride wrapped in the carbon layer, resulting in a large amount of fluorine resources wasted. Traditional residual anode treatment methods are often unable to effectively remove these impurities, resulting in low fluoride recovery rates (<60%) and poor carbon powder purity (<85%).
[0004] The presence of fluorine and sodium impurities in aluminum electrolytic cells can have numerous adverse effects on equipment and production processes. Fluoride is highly corrosive and can react with metal components in the electrolytic cell, causing corrosion and damage to equipment, increasing maintenance costs and the frequency of equipment replacement. Furthermore, the presence of fluoride can affect the current efficiency during the electrolysis process, as fluoride ions may react with aluminum ions to produce undesirable substances, thereby reducing aluminum deposition efficiency. Furthermore, the presence of fluoride and sodium salts can increase the viscosity of the electrolyte, affecting its fluidity, and thus hindering the migration of aluminum ions and the proper functioning of the electrolytic reaction.
[0005] Therefore, it is necessary to design a method for treating electrolyte residual anodes to solve the problems of low fluorine / sodium recovery rate and poor carbon powder purity in traditional treatment methods. Summary of the Invention
[0006] In view of this, the present invention proposes a method for treating electrolyte residual anodes to solve the problems of low fluorine / sodium recovery rate and poor carbon powder purity in traditional treatment methods.
[0007] The present invention provides a method for treating electrolyte residual anodes, comprising the following preparation steps:
[0008] Pre-treating the electrolyte residual anode to obtain electrolyte residual anode carbon powder;
[0009] The electrolyte residual anode carbon powder is mixed with a sodium hydroxide solution, subjected to ultrasonic alkaline leaching treatment, and separated to obtain a leachate and a leach residue;
[0010] After washing the leached residue, vacuum filtration is performed to obtain carbon powder;
[0011] Passing calcium chloride solution into the leachate, and filtering to obtain calcium fluoride precipitate and sodium-containing solution;
[0012] washing the calcium fluoride precipitate and then drying it to obtain calcium fluoride;
[0013] The sodium-containing solution is evaporated and crystallized, and dried to obtain a sodium-containing compound.
[0014] Furthermore, the pretreatment is specifically as follows: crushing the electrolyte anode residue and drying it to obtain electrolyte anode residue carbon powder.
[0015] Furthermore, the drying temperature is 50-80° C., and the drying time is 4-6 hours.
[0016] Furthermore, the electrolyte residual anode carbon powder has particles with a size of 200 mesh or larger accounting for 70-100%.
[0017] Furthermore, the concentration of the sodium hydroxide solution is 20-120 g / L.
[0018] Furthermore, the solid-to-liquid ratio of the electrolyte residual anode carbon powder to the sodium hydroxide solution is 3:1-7:1.
[0019] Furthermore, the ultrasonic alkali leaching treatment has an ultrasonic power of 200-350W, an alkali leaching temperature of 35-95°C, and a leaching time of 20-130 minutes.
[0020] Furthermore, the temperature of the evaporation crystallization is 80-100°C.
[0021] Compared with the existing technology, the beneficial effect of the present invention is that: the present invention adopts ultrasonic enhancement technology to break the carbon layer packaging structure through the cavitation effect, exposing the internal fluoride, thereby significantly improving the leaching rate of fluoride and sodium, and at the same time achieving efficient recovery and high-purity purification of carbon powder. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:
[0023] Figure 1A flow chart of the electrolyte residue anode treatment method provided by the embodiment of the present application is shown in FIG. 1.
[0024] Figure 2 A SEM image of the electrolyte residue anode before ultrasonic alkali leaching treatment in the embodiment 3 of the present application is shown in FIG. 2.
[0025] Figure 3 A SEM image of the electrolyte residue anode after ultrasonic alkali leaching treatment in the embodiment 3 of the present application is shown in FIG. 3. DETAILED DESCRIPTION
[0026] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood, and the scope of the present disclosure can be accurately conveyed to those skilled in the art. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.
[0027] With the continuous expansion of China's electrolytic aluminum production capacity, the industry's annual output is expected to break through 43 million tons in 2024. In addition to generating waste cathode carbon blocks during the operation of electrolytic cells, a large amount of residual anode material containing fluorine / sodium compounds is also generated. According to statistics, 22-32 kg of residual anode will be generated for every ton of aluminum produced, and its main components are carbon matrix (50-65 wt%), sodium fluoride (0.5-8 wt%), aluminum fluoride (2-10 wt%), and trace cyanide.
[0028] The existing technology usually adopts landfill method, fire treatment and wet leaching treatment method, but the landfill method will cause fluoride to seep into groundwater, causing soil and water pollution, and cannot realize resource recycling. The fire treatment has high energy consumption (>1200℃) and is easy to produce harmful gases such as HF, which poses a threat to the environment and the health of operating personnel. The conventional wet leaching method has an extraction rate of less than 60% for sodium fluoride wrapped in the carbon layer, resulting in a large waste of fluorine resources. The traditional residual anode treatment method often cannot effectively remove these impurities, resulting in low fluorine recovery rate (<60%) and poor carbon powder purity (<85%).
[0029] The presence of fluorine and sodium impurities in aluminum electrolytic cells can have many adverse effects on equipment and production processes. Fluoride is highly corrosive and can react with metal parts in the electrolytic cell, causing corrosion damage to the equipment, increasing maintenance costs and the frequency of equipment replacement. At the same time, the presence of fluoride will affect the current efficiency during the electrolysis process, because fluoride ions may react with aluminum ions during the electrolysis process to produce undesirable substances, thereby reducing the deposition efficiency of aluminum. In addition, the presence of fluoride and sodium salts may also increase the viscosity of the electrolyte, affecting the fluidity of the electrolyte, and further affecting the migration of aluminum ions and the normal progress of the electrolysis reaction. Therefore, it is necessary to design a method for treating electrolyte residual anodes to solve the problems of low fluorine / sodium recovery rate and poor carbon powder purity in traditional treatment methods.
[0030] like Figure 1 As shown, in some embodiments of the present application, a method for treating electrolyte residual anodes includes the following preparation steps:
[0031] Pre-treating the electrolyte residual anode to obtain electrolyte residual anode carbon powder;
[0032] The electrolyte residual anode carbon powder is mixed with a sodium hydroxide solution, subjected to ultrasonic alkaline leaching treatment, and separated to obtain a leachate and a leach residue;
[0033] After washing the leached residue, vacuum filtration is performed to obtain carbon powder;
[0034] Passing calcium chloride solution into the leachate, and filtering to obtain calcium fluoride precipitate and sodium-containing solution;
[0035] washing the calcium fluoride precipitate and then drying it to obtain calcium fluoride;
[0036] The sodium-containing solution is evaporated and crystallized, and dried to obtain a sodium-containing compound.
[0037] Specifically, the electrolyte residual anode has a fluorine content of 0.46 wt% and a sodium content of 0.19 wt%.
[0038] Specifically, when washing the leached residue, the leached residue was countercurrently washed with deionized water at a solid-liquid ratio of 1:10 for 5 times.
[0039] Specifically, when washing the calcium fluoride precipitate, the calcium fluoride precipitate is countercurrently washed with deionized water at a solid-liquid ratio of 1:10 for 5 times.
[0040] Specifically, when the calcium chloride solution is introduced, a small amount of calcium chloride solution should be introduced, and the residual fluoride ions combine with sodium ions to form sodium fluoride, and a sodium-containing compound can be obtained subsequently.
[0041] It's understood that the ultrasonic cavitation effect during ultrasonic alkaline leaching generates microjets that break up the carbon layer (with a strength of up to 100 MPa), exposing the internal fluoride. The thermal effect (local temperature of 5000 K) accelerates solid-liquid mass transfer, and the mechanical vibration (frequency of 20-40 kHz) prevents particle agglomeration. Experiments have shown that ultrasonic leaching can increase the fluoride and sodium leaching rate by 3-5 times compared to traditional stirring.
[0042] In some embodiments of the present application, the pretreatment specifically comprises: crushing the electrolyte anode residue and drying it to obtain electrolyte anode residue carbon powder.
[0043] In some embodiments of the present application, the drying temperature is 50-80° C., and the drying time is 4-6 hours; the drying temperature is preferably 60° C., and the drying time is preferably 5 hours.
[0044] It can be understood that drying can remove moisture and some impurities from the electrolyte residual anode carbon powder.
[0045] In some embodiments of the present application, the electrolyte residual anode carbon powder has particles with a size of 200 mesh or larger accounting for 70-100%; the particles with a size of 200 mesh or larger accounting for preferably 90-100%, and more preferably 90%.
[0046] Specifically, during the crushing process, a jaw crusher is first used to preliminarily crush the electrolyte residual anode, and then a ball mill is used to crush the electrolyte residual anode to particles larger than 200 mesh, with the proportion of the particles being 70-100%.
[0047] In some embodiments of the present application, the concentration of the sodium hydroxide solution is 20-120 g / L, preferably 60-100 g / L, and more preferably 100 g / L.
[0048] In some embodiments of the present application, the solid-to-liquid ratio of the electrolyte residual anode carbon powder to the sodium hydroxide solution is 3:1-7:1, preferably 4:1-7:1, and more preferably 7:1.
[0049] In some embodiments of the present application, the ultrasonic power of the ultrasonic alkali leaching treatment is 200-350W, the alkali leaching temperature is 35-95°C, and the leaching time is 20-130 minutes; the ultrasonic power of 200-350W is preferably 250-300W, and more preferably 300W; the alkali leaching temperature is preferably 70-80°C, and more preferably 80°C; the leaching time is preferably 30-120 minutes, and more preferably 30 minutes.
[0050] Specifically, the reaction container used in the ultrasonic alkali leaching treatment is a polytetrafluoroethylene beaker, and the ultrasonic equipment used is an insertion probe type ultrasonic equipment.
[0051] In some embodiments of the present application, the temperature of the evaporative crystallization is 80-100°C.
[0052] Specifically, when performing the evaporation crystallization, the temperature is first controlled at 80° C. to obtain sodium chloride crystals, and then the temperature is increased to 100° C. to obtain sodium fluoride crystals.
[0053] Example 1
[0054] S1. A residual electrolyte anode with a fluorine content of 0.46 wt% and a sodium content of 0.19 wt% was crushed by a jaw crusher, and then ground by a ball mill until the proportion of particles larger than 200 mesh was 80%, and dried at 50° C. for 4 hours to obtain residual electrolyte anode carbon powder;
[0055] S2, taking 150g of the electrolyte residual anode carbon powder and 450ml of 20g / L sodium hydroxide solution, mixing them and placing them in a polytetrafluoroethylene beaker, setting the ultrasonic power to 200W, and treating them at a temperature of 35°C for 20 minutes, and separating them after completion to obtain a leachate and a leach residue;
[0056] S3, countercurrent washing the leached residue with deionized water at a solid-liquid ratio of 1:10 for 5 times, and vacuum filtering to obtain carbon powder;
[0057] S4, passing calcium chloride solution into the leachate, filtering to obtain calcium fluoride precipitate and sodium-containing solution;
[0058] S5, countercurrently washing the calcium fluoride precipitate with deionized water at a solid-to-liquid ratio of 1:10 for 5 times, and drying at 50° C. for 4 hours to obtain calcium fluoride;
[0059] S6. Raising the temperature of the sodium-containing solution to 80° C. to obtain sodium chloride crystals, and then raising the temperature to 100° C. to obtain sodium fluoride crystals.
[0060] Example 2
[0061] S1. A residual electrolyte anode with a fluorine content of 0.46 wt% and a sodium content of 0.19 wt% was crushed by a jaw crusher, and then ground by a ball mill until the proportion of particles larger than 200 mesh was 90%, and dried at 60° C. for 5 hours to obtain residual electrolyte anode carbon powder;
[0062] S2, taking 200g of the electrolyte residual anode carbon powder and 800ml of 80g / L sodium hydroxide solution, mixing them and placing them in a polytetrafluoroethylene beaker, setting the ultrasonic power to 250W, and treating at a temperature of 75°C for 40 minutes, and separating them after completion to obtain a leachate and a leach residue;
[0063] S3, countercurrent washing the leached residue with deionized water at a solid-liquid ratio of 1:10 for 5 times, and vacuum filtering to obtain carbon powder;
[0064] S4, a calcium chloride solution is introduced into the leaching solution, and filtration is performed to obtain a calcium fluoride precipitate and a sodium-containing solution;
[0065] S5, the calcium fluoride precipitate is countercurrently washed with deionized water at a solid-liquid ratio of 1:10 for 5 times, and is dried at 60°C for 5 hours to obtain calcium fluoride;
[0066] S6, the temperature of the sodium-containing solution is increased to 80°C to obtain sodium chloride crystals, and then the temperature is increased to 100°C to obtain sodium fluoride crystals.
[0067] Example 3
[0068] S1, an electrolyte residual anode with a fluorine content of 0.46wt% and a sodium content of 0.19wt% is crushed by a jaw crusher, and is ground by a ball mill to a particle size of 200 mesh or more, and the proportion of particles of 90% or more is obtained, and is dried at 60°C for 5 hours to obtain electrolyte residual anode carbon powder;
[0069] S2, 200g of the electrolyte residual anode carbon powder and 1400ml of 100g / L sodium hydroxide solution are mixed and placed in a polytetrafluoroethylene beaker, an ultrasonic power of 300W is set, and the temperature is 85°C, and the treatment is carried out for 30 minutes, and after the end, separation is carried out, and a leaching solution and a leaching residue are obtained;
[0070] S3, the leaching residue is countercurrently washed with deionized water at a solid-liquid ratio of 1:10 for 5 times, and vacuum filtration is performed to obtain carbon powder;
[0071] S4, a calcium chloride solution is introduced into the leaching solution, and filtration is performed to obtain a calcium fluoride precipitate and a sodium-containing solution;
[0072] S5, the calcium fluoride precipitate is countercurrently washed with deionized water at a solid-liquid ratio of 1:10 for 5 times, and is dried at 60°C for 5 hours to obtain calcium fluoride;
[0073] S6, the temperature of the sodium-containing solution is increased to 80°C to obtain sodium chloride crystals, and then the temperature is increased to 100°C to obtain sodium fluoride crystals.
[0074] Example 4
[0075] S1, an electrolyte residual anode with a fluorine content of 0.46wt% and a sodium content of 0.19wt% is crushed by a jaw crusher, and is ground by a ball mill to a particle size of 200 mesh or more, and the proportion of particles of 90% or more is obtained, and is dried at 60°C for 5 hours to obtain electrolyte residual anode carbon powder;
[0076] S2, 200g of the electrolyte residual anode carbon powder and 1400ml of 100g / L sodium hydroxide solution are mixed and placed in a polytetrafluoroethylene beaker, an ultrasonic power of 300W is set, and the temperature is 85°C, and the treatment is carried out for 30 minutes, and after the end, separation is carried out, and a leaching solution and a leaching residue are obtained;
[0077] S3, the leaching residue is washed countercurrently with deionized water at a solid-liquid ratio of 1:10 for 5 times, and carbon powder is obtained after vacuum filtration;
[0078] S4, a calcium chloride solution is introduced into the leaching solution, and calcium fluoride precipitate and a sodium-containing solution are obtained by filtration;
[0079] S5, the calcium fluoride precipitate is washed countercurrently with deionized water at a solid-liquid ratio of 1:10 for 5 times, and calcium fluoride is obtained after drying at 80°C for 6 hours;
[0080] S6, the temperature of the sodium-containing solution is increased to 80°C to obtain sodium chloride crystals, and then the temperature is increased to 100°C to obtain sodium fluoride crystals.
[0081] Example 5
[0082] S1, the electrolyte residual anode with a fluorine content of 0.46wt% and a sodium content of 0.19wt% is crushed by a jaw crusher, ground to a particle size of 200 mesh or more by a ball mill, and dried at 60°C for 5 hours to obtain electrolyte residual anode carbon powder;
[0083] S2, 200g of the electrolyte residual anode carbon powder and 1400ml of 100g / L sodium hydroxide solution are mixed and placed in a polytetrafluoroethylene beaker, an ultrasonic power of 300W is set, and the temperature is 85°C for 30 minutes, then separated to obtain a leaching solution and a leaching residue;
[0084] S3, the leaching residue is washed countercurrently with deionized water at a solid-liquid ratio of 1:10 for 5 times, and carbon powder is obtained after vacuum filtration;
[0085] S4, a calcium chloride solution is introduced into the leaching solution, and calcium fluoride precipitate and a sodium-containing solution are obtained by filtration;
[0086] S5, the calcium fluoride precipitate is washed countercurrently with deionized water at a solid-liquid ratio of 1:10 for 5 times, and calcium fluoride is obtained after drying at 60°C for 5 hours;
[0087] S6, the temperature of the sodium-containing solution is increased to 80°C to obtain sodium chloride crystals, and then the temperature is increased to 100°C to obtain sodium fluoride crystals.
[0088] Example 6
[0089] S1, the electrolyte residual anode with a fluorine content of 0.46wt% and a sodium content of 0.19wt% is crushed by a jaw crusher, ground to a particle size of 200 mesh or more by a ball mill, and dried at 60°C for 5 hours to obtain electrolyte residual anode carbon powder;
[0090] S2, 200g of the electrolyte residual anode carbon powder and 1400ml of 100g / L sodium hydroxide solution were mixed and placed in a polytetrafluoroethylene beaker, the ultrasonic power was set to 300W, the temperature was 85℃, and the treatment was carried out for 30 minutes, then the leaching liquid and the leaching residue were separated;
[0091] S3, the leaching residue was countercurrently washed with deionized water at a solid-liquid ratio of 1:10 for 5 times, and then vacuum filtration was carried out to obtain the carbon powder;
[0092] S4, the calcium chloride solution was introduced into the leaching liquid, and the calcium fluoride precipitate and the sodium-containing solution were obtained by filtration;
[0093] S5, the calcium fluoride precipitate was countercurrently washed with deionized water at a solid-liquid ratio of 1:10 for 5 times, and then dried at 60℃ for 5 hours to obtain calcium fluoride;
[0094] S6, the temperature of the sodium-containing solution was increased to 80℃ to obtain sodium chloride crystals, and then the temperature was increased to 100℃ to obtain sodium fluoride crystals.
[0095] Comparative Example 1
[0096] S1, the electrolyte residual anode with a fluorine content of 0.46wt% and a sodium content of 0.19wt% was crushed by a jaw crusher, and then ground by a ball mill to a particle size of 200 mesh or more, and the particle size accounted for 90%, and then dried at 60℃ for 5 hours to obtain the electrolyte residual anode carbon powder;
[0097] S2, 200g of the electrolyte residual anode carbon powder and 800ml of 80g / L sodium hydroxide solution were mixed and placed in a polytetrafluoroethylene beaker, mechanical stirring (800r / min) was carried out, 70℃ leaching was carried out for 120 minutes, and then the leaching liquid and the leaching residue were separated.
[0098] Effect test:
[0099] 1, the fluorine element and sodium element content of the leaching liquid of the embodiment 2 and the comparative example 1 were detected, and the leaching rate was calculated:
[0100] Through the test, the fluorine element leaching rate of the embodiment 2 was 92.3%, the sodium element leaching rate was 94.5%, the leaching liquid (F-concentration 12.6g / L, Na + concentration 14.2g / L) was obtained, while the fluorine element leaching rate of the comparative example 1 was 52.1%, the sodium element leaching rate was 58.3%, and the leaching liquid (F-concentration 7.2g / L, Na + concentration 8.6g / L).
[0101] It can be seen that compared with the conventional alkali leaching method, the leaching rates of fluorine element and sodium element are greatly improved.
[0102] 2. The leachate of Example 2 and Example 3 was detected for the content of fluorine and sodium elements, and the leaching rate and unit energy consumption were calculated:
[0103] The detected results showed that compared with Example 2, Example 3 optimized the parameters for electrolyte carbon powder, the concentration of NaOH was increased to 100 g / L, the liquid-solid ratio was adjusted to 7:1, and the treatment was carried out at 300 W ultrasonic, 80°C for 30 minutes. The results showed that the fluorine / sodium leaching rates of Example 3 were 93.5% and 96.8%, respectively, and the F- / Na+ concentration of the leachate was 0.014wt% / 0.019wt%. + The concentration was increased to 38.2 g / L and 40.5 g / L, the purity of carbon powder was 97.6% (fluorine / sodium residue 0.014wt% / 0.019wt%), the energy consumption of Example 2 was 18 kW·h / t, and the energy consumption of Example 3 was 22 kW·h / t, which was only increased by 22% compared with Example 2.
[0104] 3. The leachate of Example 3, Example 5 and Example 6 was detected for the content of fluorine and sodium elements, and the leaching rate, unit energy consumption and carbon powder purity were calculated.
[0105] The detection results showed that the fluorine / sodium leaching rates of Example 3 (200 mesh accounted for 90%) were 92.3% / 94.5%, and the purity of carbon powder was 97.6%, which was the best balance point; although the purity of carbon powder of Example 6 (200 mesh accounted for 100%) reached 97.8%, the crushing energy consumption increased by 35%; the fluorine / sodium leaching rates of Example 5 (200 mesh accounted for 70%) were only 82.3% / 79.8%.
[0106] The results proved that the 200 mesh accounted for ≥90% was the critical value of the process.
[0107] 4. The electrolyte residual anode of Example 3 before and after ultrasonic alkaline leaching treatment was detected by X-ray diffraction, and the results are shown in Tables 1-2:
[0108] Table 1 Element content table of electrolyte residual anode before ultrasonic alkaline leaching treatment
[0109] Element O F S Fe Al Ca Content (wt. %) 3.5240 0.6069 6.0753 1.2584 0.2464 0.2724
[0110] Table 1 Element content table of electrolyte residual anode after ultrasonic alkaline leaching treatment
[0111] Element O F S Fe Al Ca Content (wt. %) 3.6876 0.0220 6.0485 1.3562 0.1855 0.5497
[0112] It can be seen that the O, F, S, Fe, Al and Ca element contents of the electrolyte residual anode after ultrasonic alkaline leaching treatment were significantly increased.
[0113] 5. The electrolyte residual anode of Example 3 before and after ultrasonic alkaline leaching treatment was detected by SEM, and the results are shown in Figures 2-3
[0114] The surface of the treated electrolyte residual anode carbon particles forms microcracks of 0.5-2 μm.
[0115] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of the present application.
Claims
1. A method for treating residual electrolyte anodes, characterized in that: The method comprises the following preparation steps: Pre-treating the electrolyte residual anode to obtain electrolyte residual anode carbon powder; The electrolyte residual anode carbon powder is mixed with a sodium hydroxide solution, subjected to ultrasonic alkaline leaching treatment, and separated to obtain a leachate and a leach residue; After washing the leached residue, vacuum filtration is performed to obtain carbon powder; Passing calcium chloride solution into the leachate, and filtering to obtain calcium fluoride precipitate and sodium-containing solution; washing the calcium fluoride precipitate and then drying it to obtain calcium fluoride; The sodium-containing solution is evaporated and crystallized, and dried to obtain a sodium-containing compound.
2. The electrolyte residual anode treatment method according to claim 1, characterized in that: The pretreatment specifically comprises: crushing the electrolyte residual anode and drying it to obtain electrolyte residual anode carbon powder.
3. The electrolyte residual anode treatment method according to claim 2, characterized in that: The drying temperature is 50-80° C., and the drying time is 4-6 hours.
4. The electrolyte residual anode treatment method according to claim 3, characterized in that: The electrolyte residual anode carbon powder has particles with a size of 200 mesh or larger accounting for 70-100%.
5. The electrolyte residual anode treatment method according to claim 4, characterized in that: The concentration of the sodium hydroxide solution is 20-120 g / L.
6. The electrolyte residual anode treatment method according to claim 5, characterized in that: The solid-to-liquid ratio of the electrolyte residual anode carbon powder to the sodium hydroxide solution is 3:1-7:
1.
7. The electrolyte residual anode treatment method according to claim 6, characterized in that: The ultrasonic alkali leaching treatment has an ultrasonic power of 200-350W, an alkali leaching temperature of 35-95°C, and a leaching time of 20-130 minutes.
8. The electrolyte residual anode treatment method according to claim 7, characterized in that: The temperature of the evaporation crystallization is 80-100°C.