Preparation method of cobalt tetraoxide catalyst and application thereof
The preparation of cobalt tetroxide catalyst by oxidative roasting method solves the problem of low cobalt leaching rate in lithium-ion battery recycling, realizes efficient and environmentally friendly cobalt extraction and catalyst preparation, and has good catalytic performance and economic benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUAQIAO UNIVERSITY
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-07
AI Technical Summary
In existing lithium-ion battery recycling processes, the leaching rate and selectivity of metals such as lithium and cobalt are low, and there are risks of metal loss and secondary pollution. Traditional methods are carried out under high temperature and high acid conditions, which are complex and environmentally unfriendly.
Cobalt tetroxide catalyst was prepared by oxidative roasting. Purification agents such as NaHSO4, KHSO4, (NH4)2SO4, NH4HSO4, NaNH4SO4, NH4NO3, NH4Cl or NaCl were mixed with waste lithium cobalt oxide battery cathode powder and oxidized and roasted at 500-700℃. After ball milling and water immersion washing, high-purity cobalt tetroxide catalyst was prepared.
The extraction rate and selectivity of cobalt were improved, and the resulting catalyst had good catalytic performance and could be used for the degradation of organic wastewater, realizing high-value utilization of waste and low-cost preparation.
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Figure CN119746862B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of waste lithium-ion battery resource utilization technology, specifically relating to a method for preparing cobalt tetroxide catalyst and its application. Background Technology
[0002] With the rapid iteration of portable electronic products and the booming development of the new energy vehicle industry, a large number of lithium-ion batteries are being scrapped and retired. Lithium-ion batteries that have reached the end of their service life contain a large amount of organic electrolyte, graphite and heavy metals, which can affect human health and the healthy development of the new energy industry. Voluntary recycling of retired lithium-ion batteries is the key to solving the problem and achieving a win-win situation for both the economy and the environment.
[0003] Currently, the industrial production of lithium-ion battery resource recycling mainly employs two methods: pyrometallurgy, used in Europe and the United States, and hydrometallurgy, used in my country. Pyrometallurgy involves directly crushing waste batteries and then performing high-temperature reduction smelting to obtain an Fe-Co-Ni alloy, while the lithium resources are discarded as slag. Domestic hydrometallurgical enterprises primarily use sulfuric acid as a leaching agent and hydrogen peroxide as a reducing agent to leach the metals, followed by graded extraction. This method can achieve efficient recovery of metals such as lithium, cobalt, nickel, and manganese. However, due to the coexistence of multiple metal ions in the acid leaching system, the extraction and separation process is complex and prone to metal and reagent loss, as well as the risk of secondary pollution.
[0004] Salt-roasting, by adding additives, can significantly reduce the decomposition temperature of cathode materials and is widely used in the recycling of cathode materials from spent lithium-ion batteries. Depending on the additives, salt-roasting processes mainly include sulfation roasting (or sulfurization roasting), chlorination roasting, and nitration roasting. Lin et al. conducted a study on lithium extraction by sulfation roasting of NCM cathode powder. After thoroughly mixing and drying the cathode powder with 98wt% concentrated sulfuric acid, they roasted it at 800℃ for 120 min, achieving a Li leaching rate of 96.92wt%. The leaching rates of Al, Cu, Ni, Co, and Mn were all less than or approximately 1wt%. This method achieved a high Li leaching rate, but it requires strong acid and high temperature conditions and did not achieve selective separation of Al, Cu, Ni, Co, and Mn. In the inventors' preliminary research, NH4Cl was used as a chlorinating agent to chlorinate and roast LMO cathode powder in an oxygen atmosphere, achieving selective chlorination of lithium and a Li leaching rate of 91.73wt%. Peng et al. achieved a leaching rate of 93 wt% for Li obtained by water leaching after nitration (70℃, 5h, nitric acid waste ratio of 30 mmol / g) and selective roasting (250℃, 1h). Although the above two methods have milder reaction conditions, their leaching rates and selectivity are lower. Summary of the Invention
[0005] The purpose of this invention is to overcome the defects of the prior art and provide a method for preparing cobalt tetroxide catalyst and its application. This method for preparing cobalt tetroxide catalyst has the advantages of mild reaction conditions, high yield and high selectivity, and the obtained cobalt tetroxide catalyst has good catalytic effect.
[0006] The technical solution of the present invention is as follows:
[0007] A method for preparing cobalt tetroxide catalyst includes: mixing the positive electrode powder of waste lithium cobalt oxide battery with a purified reagent and spreading it evenly in a reaction device, and then performing an oxidative calcination treatment to obtain cobalt tetroxide catalyst;
[0008] The purifying agent is at least one of NaHSO4, KHSO4, (NH4)2SO4, NH4HSO4, NaNH4SO4, NH4NO3, NH4Cl, and NaCl, and the molar ratio of the negative charge of the positive electrode powder to the negative charge of the anion in the purifying agent is 1:4 to 8.
[0009] The thickness of the positive electrode powder and the mixed purification agent should not exceed 2 cm.
[0010] The oxidative roasting temperature is 500–700℃, the oxidative roasting time is 0.5–2h, and the oxygen partial pressure in the oxidative roasting atmosphere is not less than 10kPa.
[0011] Preferably, the atmosphere for oxidative roasting is oxygen or air, and the flow rate of the atmosphere is 50-100 mL / min.
[0012] Preferably, the preparation method further includes: after oxidative roasting, the product is ball-milled and washed with water.
[0013] More preferably, the ball milling speed is 2000-3000 rpm and the ball milling time is 0.5-1 h.
[0014] More preferably, the solid-liquid ratio for water immersion washing is 50–100 g / L, and the water immersion washing time is 1–2 h.
[0015] Preferably, the method for preparing the positive electrode powder is as follows: dismantling waste lithium cobalt oxide batteries to obtain positive electrode sheets, pyrolyzing the positive electrode sheets to remove the binder, and then separating and collecting them.
[0016] More preferably, the pyrolysis treatment is carried out in an inert atmosphere, the temperature of the pyrolysis treatment is 450-550℃, and the time of the pyrolysis treatment is 1-2 hours.
[0017] A cobalt tetroxide catalyst was prepared by the above-described method.
[0018] Application of the cobalt tetroxide catalyst prepared by the above method as a catalytic material.
[0019] A photocatalyst comprising a cobalt tetroxide catalyst prepared by the above-described method.
[0020] The present invention has at least the following beneficial effects:
[0021] This invention fully utilizes commercially available waste lithium-ion battery materials to prepare cobalt tetroxide catalysts. By improving the preparation conditions, the extraction rate and selectivity of cobalt are enhanced. The resulting cobalt tetroxide catalyst exhibits comparable catalytic performance to commercially available cobalt tetroxide catalysts and can be used as a catalyst for the degradation of organic wastewater. Furthermore, this method directly utilizes waste cathode materials to prepare highly efficient catalysts, avoiding the use of expensive high-purity metal salts and achieving added value utilization of waste. This results in the low-cost preparation of high-value-added catalysts, demonstrating significant economic and social benefits. Attached Figure Description
[0022] Figure 1 This is a process route diagram for preparing cobalt tetroxide catalyst from waste lithium cobalt oxide battery cathode material according to the present invention;
[0023] Figure 2 The images show the morphology of the cathode powder (a, b) and the prepared cobalt tetroxide catalyst (c, d) used in Example 1.
[0024] Figure 3 The X-ray diffraction (XRD) patterns of the cobalt tetroxide catalysts prepared in Examples 1-6 are shown.
[0025] Figure 4 The graph shows the degradation efficiency of cobalt tetroxide catalysts prepared in Examples 1-6 for the catalytic degradation of tetracycline. Detailed Implementation
[0026] The technical solution of the present invention will be further explained and described below through specific embodiments.
[0027] In the following embodiments, the water used can be one or more of distilled water, purified water, and drinking water; unless otherwise specified, the detection methods in the following embodiments are conventional detection methods; unless otherwise specified, the reagents in the following embodiments are all purchased from commercial channels.
[0028] In the following embodiments, the positive electrode powder is obtained by dismantling waste lithium cobalt oxide batteries to obtain positive electrode sheets, followed by pyrolysis treatment at 450°C for 1 hour to remove the binder. In other possible implementations, the positive electrode powder can be obtained by dismantling and purifying waste lithium cobalt oxide batteries using techniques commonly used by those skilled in the art.
[0029] In the following embodiments, in the molar ratio of positive electrode powder to purification reagent, the amount of positive electrode powder is calculated as the mass of positive electrode powder / the molecular weight of lithium cobalt oxide, and the amount of purification reagent is calculated as the amount of negative charge of its anions.
[0030] Example 1
[0031] This embodiment provides a method for preparing a cobalt tetroxide catalyst, such as... Figure 1 It includes the following steps:
[0032] 1. The positive electrode powder and NH4Cl were uniformly mixed at a molar ratio of 1:6 and spread into a reaction vessel with a thickness of 0.5 cm. Then, the mixture was oxidized and calcined in air with an oxygen partial pressure of 20 kPa. The air flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 0.5 h.
[0033] 2. The residue after the reaction was ball-milled, washed with water, and finally filtered and dried to obtain cobalt tetroxide catalyst. The ball-milling conditions were: 2000 rpm for 1 hour; the water washing conditions were: solid-liquid ratio of 50 g / L for 1 hour. The impurity ion removal rate was 99.23%, and the yield of cobalt tetroxide catalyst was 99.34%.
[0034] Example 2
[0035] This embodiment provides a method for preparing a cobalt tetroxide catalyst, such as... Figure 1 It includes the following steps:
[0036] 1. The positive electrode powder and NH4Cl were uniformly mixed at a molar ratio of 1:6 and spread to a thickness of 2 cm in a reaction vessel. Then, the mixture was oxidized and calcined in air with an oxygen partial pressure of 20 kPa. The air flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 700 °C, and the reaction time at 0.5 h.
[0037] 2. The residue after the reaction was ball-milled, washed with water, and finally filtered and dried to obtain cobalt tetroxide catalyst. The ball-milling conditions were: 2000 rpm for 1 hour; the water washing conditions were: solid-liquid ratio of 50 g / L for 1 hour. The impurity ion removal rate was 97.95%, and the yield of cobalt tetroxide catalyst was 98.76%.
[0038] Example 3
[0039] This embodiment provides a method for preparing a cobalt tetroxide catalyst, such as... Figure 1 It includes the following steps:
[0040] 1. The positive electrode powder and (NH4)S2O8 were uniformly mixed at a molar ratio of 1:4 and spread into a reaction vessel with a thickness of 0.5 cm. Then, the mixture was oxidized and calcined in air with an oxygen partial pressure of 10 kPa. The air flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 0.5 h.
[0041] 2. The residue after the reaction was ball-milled, washed with water, and finally filtered and dried to obtain cobalt tetroxide catalyst. The ball-milling conditions were: 2000 rpm for 1 hour; the water washing conditions were: solid-liquid ratio of 50 g / L for 1 hour. The impurity ion removal rate was 99.50%, and the yield of cobalt tetroxide catalyst was 99.56%.
[0042] Example 4
[0043] This embodiment provides a method for preparing a cobalt tetroxide catalyst, such as... Figure 1 It includes the following steps:
[0044] 1. Mix the positive electrode powder with NaHSO4 (in a 1 / 2 ratio of SO42-22-24 ... 2- The mixture was homogeneously mixed at a molar ratio of 1:4 and spread to a thickness of 0.5 cm in a reaction vessel. It was then oxidized and calcined in air with an oxygen partial pressure of 30 kPa. The air flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 0.5 h.
[0045] 2. The residue after the reaction was ball-milled, washed with water, and finally filtered and dried to obtain cobalt tetroxide catalyst. The ball-milling conditions were: 2000 rpm for 1 hour; the water washing conditions were: solid-liquid ratio of 50 g / L for 1 hour. The impurity ion removal rate was 96.13%, and the yield of cobalt tetroxide catalyst was 99.29%.
[0046] Example 5
[0047] This embodiment provides a method for preparing a cobalt tetroxide catalyst, such as... Figure 1 It includes the following steps:
[0048] 1. The positive electrode powder and NH4Cl were uniformly mixed at a molar ratio of 1:6 and spread into a reaction vessel to a thickness of 2 cm. Then, oxidation calcination was carried out in oxygen. The oxygen flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 0.5 h.
[0049] 2. The residue after the reaction was ball-milled, washed with water, and finally filtered and dried to obtain cobalt tetroxide catalyst. The ball-milling conditions were: 2000 rpm for 1 hour; the water washing conditions were: solid-liquid ratio of 50 g / L for 1 hour. The impurity ion removal rate was 99.78%, and the yield of cobalt tetroxide catalyst was 99.61%.
[0050] Example 6
[0051] This embodiment provides a method for preparing a cobalt tetroxide catalyst, such as... Figure 1 It includes the following steps:
[0052] 1. The positive electrode powder and NH4Cl were uniformly mixed at a molar ratio of 1:6 and spread into a reaction vessel with a thickness of 0.5 cm. Then, the mixture was oxidized and calcined in air with an oxygen partial pressure of 20 kPa. The air flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 2 h.
[0053] 2. The residue after the reaction was ball-milled, washed with water, and finally filtered and dried to obtain cobalt tetroxide catalyst. The ball-milling conditions were: 2000 rpm for 1 hour; the water washing conditions were: solid-liquid ratio of 50 g / L for 1 hour. The impurity ion removal rate was 99.56%, and the yield of cobalt tetroxide catalyst was 98.23%.
[0054] Comparative Example 1
[0055] The preparation method of this comparative example includes the following steps:
[0056] 1. The positive electrode powder and NH4Cl were uniformly mixed at a molar ratio of 1:1 and spread in a reaction vessel to a thickness of 3 cm. Then, the mixture was oxidized and calcined in air with an oxygen partial pressure of 20 kPa. The air flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 0.5 h.
[0057] 2. The residue after the reaction was ball-milled, washed with water, and finally filtered and dried to obtain the product. The ball-milling conditions were: 2000 rpm for 1 hour; the water washing conditions were: solid-liquid ratio of 50 g / L for 1 hour. The impurity ion removal rate was 28.71%, and the yield of cobalt tetroxide was 27.24%.
[0058] Because the amount of purification reagent used was too low, the removal of impurity ions was incomplete, and the resulting product was a mixture of lithium cobalt oxide and cobalt tetroxide.
[0059] Comparative Example 2
[0060] The preparation method of this comparative example includes the following steps:
[0061] 1. The positive electrode powder and NH4Cl were uniformly mixed at a molar ratio of 1:4, and the mixture was spread into a reaction vessel with a thickness of 0.5 cm. Then, the mixture was calcined under nitrogen atmosphere. The nitrogen flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 0.5 h.
[0062] 2. The residue after the reaction is ball-milled, washed with water, and finally filtered and dried to obtain the product. The ball-milling conditions are: rotation speed 2000 rpm, time 1 h; the water washing conditions are: solid-liquid ratio 50 g / L, time 1 h. Cobalt ions are removed along with other impurity ions.
[0063] Because the oxygen partial pressure in the reaction was too low (almost oxygen-free), a large number of cobalt ions could not effectively participate in the synthesis reaction, and ultimately no effective catalyst was synthesized.
[0064] Comparative Example 3
[0065] The preparation method of this comparative example includes the following steps:
[0066] 1. The positive electrode powder and NH4HCO3 were uniformly mixed at a molar ratio of 1:4 and spread into a reaction vessel with a thickness of 0.5 cm. Then, the mixture was oxidized and calcined in air with an oxygen partial pressure of 20 kPa. The air flow rate was controlled at 50 mL / min, the heating rate at 5 °C / min, the reaction temperature at 500 °C, and the reaction time at 0.5 h.
[0067] 2. The residue after the reaction is ball-milled, washed with water, and finally filtered and dried to obtain the product. The ball-milling conditions are: rotation speed 2000 rpm, time 1 h; the water washing conditions are: solid-liquid ratio 50 g / L, time 1 h. The removal rate of impurity ions is less than 5%, and the yield of cobalt tetroxide catalyst is less than 5%.
[0068] Because the purification reagents used were not suitable, a large number of impurity ions could not be effectively removed, and the final residue was still waste lithium cobalt oxide powder.
[0069] Performance testing
[0070] 1. Taking Example 1 as an example, the morphology of the cathode powder (a, b) and the prepared cobalt tetroxide catalyst were measured, and the results are as follows: Figure 2 As shown, the cathode powder, after being processed by the preparation method of Example 1, transforms from an irregular spherical shape into a regular octahedral (spinel) morphology, indicating that Example 1 synthesized a classic spinel-structured cobalt tetroxide.
[0071] 2. The cobalt tetroxide catalysts prepared in Examples 1-6 were subjected to X-ray diffraction (XRD). Figure 3The diffraction pattern of Example 1 shows that, under the action of the purifying agent, impurity ions in the cathode powder are effectively removed, and a high-purity cobalt tetroxide catalyst is finally obtained.
[0072] 3. The cobalt tetroxide catalysts prepared in Examples 1-6 and commercially available cobalt tetroxide catalysts were combined with persulfate (PMS) for the catalytic degradation of tetracycline. The catalytic effects were as follows: Figure 4 As shown, the cobalt tetroxide catalysts synthesized in Examples 1-6 exhibit tetracycline degradation efficiency comparable to commercial cobalt tetroxide catalysts, indicating that the synthesized cobalt tetroxide catalysts possess superior photocatalytic performance.
[0073] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.
Claims
1. A method for preparing a cobalt tetroxide catalyst, characterized in that, include: The positive electrode powder of waste lithium cobalt oxide battery was mixed with the purification agent and spread evenly in the reaction device for oxidation roasting. After oxidation roasting, the product was ball-milled and washed with water, filtered and dried to obtain a cobalt tetroxide catalyst with an octahedral spinel structure. The purifying agent is at least one of NaHSO4, KHSO4, (NH4)2SO4, NH4HSO4, NaNH4SO4, NH4NO3, and NH4Cl, and the molar ratio of the negative charge of the positive electrode powder to the negative charge of the anion in the purifying agent is 1:4~8. The thickness of the mixture of the positive electrode powder and the purification agent after spreading is no more than 2 cm. The oxidation calcination temperature is 500~700℃, the oxidation calcination time is 0.5~2h, the oxygen partial pressure in the oxidation calcination atmosphere is not less than 10 kPa, the oxidation calcination atmosphere is oxygen or air, and the flow rate of the atmosphere is 50~100mL / min.
2. The method for preparing cobalt tetroxide catalyst as described in claim 1, characterized in that, The ball mill rotates at 2000-3000 rpm, and the milling time is 0.5-1 hour.
3. The method for preparing cobalt tetroxide catalyst as described in claim 1, characterized in that, The solid-liquid ratio of the water immersion washing is 50~100g / L, and the water immersion washing time is 1~2h.
4. The method for preparing cobalt tetroxide catalyst as described in claim 1, characterized in that, The method for preparing the positive electrode powder is as follows: dismantling waste lithium cobalt oxide batteries to obtain positive electrode sheets, pyrolyzing the positive electrode sheets to remove the binder, and then separating and collecting them.
5. The method for preparing cobalt tetroxide catalyst as described in claim 4, characterized in that, The pyrolysis treatment is carried out in an inert atmosphere, the temperature of the pyrolysis treatment is 450~550℃, and the time of the pyrolysis treatment is 1~2h.