Synthesis method of nano lithium titanate
By using titanium dioxide in discarded SCR denitrification catalysts as a titanium source, and adopting oxalic acid treatment, alkaline solution mixing and hydrothermal reaction to synthesize nano-lithium titanate, the problems of high energy consumption and high cost of the existing lithium titanate synthesis process are solved, and the green production of high-purity nano-lithium titanate is achieved.
Patent Information
- Application Number
- CN202510853235.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-09-19
AI Technical Summary
The existing lithium titanate synthesis process relies on high-energy consumption and high-cost primary titanium ore industrial products, and the amount of resource mining is large, making it difficult to achieve green production.
Titanium dioxide in waste SCR denitrification catalyst is used as the titanium source, and nano-lithium titanate is synthesized through oxalic acid treatment, alkali solution mixing, hydrothermal reaction and roasting steps. The waste catalyst is recycled as a resource to reduce costs and improve purity.
It achieves high-purity synthesis of nano-lithium titanate, reduces raw material costs, reduces mineral resource mining, and has energy-saving and carbon-reduction effects.
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Figure CN120664580A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of lithium battery materials, and in particular relates to a method for synthesizing nano-lithium titanate. Background Art
[0002] Lithium titanate (LTO) holds broad application prospects as a lithium battery anode material due to its high safety, long cycle life, and excellent low-temperature resistance. Compared to traditional graphite anode materials, LTO avoids thermal runaway and explosion at high temperatures or under overcharge. Its cycle life also far exceeds that of graphite, allowing it to withstand more charge and discharge cycles. However, existing LTO synthesis processes generally rely on primary products from the titanium ore industry, such as high-purity titanium dioxide (TiO2) or titanium tetrachloride (TiCl4), as a titanium source. The purification and production processes are energy-intensive and costly. However, the titanium dioxide content in industrial waste SCR denitrification catalysts is generally over 80%. Using metatitanic acid recovered from waste denitrification catalysts as a titanium source for LTO synthesis not only significantly reduces raw material costs but also effectively reduces mineral resource extraction, thereby saving energy and reducing carbon emissions. This technology aligns with the national "dual carbon" goals and provides an innovative solution for the green production of lithium battery anode materials. Summary of the Invention
[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method for synthesizing nano-lithium titanate.
[0004] The object of the present invention is achieved like this: A method for synthesizing nano-lithium titanate comprises the following steps: (1) Mix the oxalic acid solution with the scrapped denitrification catalyst powder and react at 90-120°C for 1-6 hours with mechanical stirring. After the reaction is completed, filter, wash, and dry to obtain the acid leaching residue. (2) Alkaline solution and acid leaching residue are mixed and added to a microscale reactor to achieve full mixing of the materials. The mixture is then added to a closed reactor and reacted at 100-150 °C for 2-10 h. Mechanical stirring is maintained during the process. After the reaction is completed, solid titanate powder is obtained by filtration, washing, and drying. (3) mixing the acid solution with the solid titanate powder of step (2), heating at 70-100° C. for 2-8 h while maintaining mechanical stirring during the process, filtering after cooling, washing, and drying to obtain metatitanate powder; (4) adding the lithium source and the titanate powder described in step (3) into a hydrothermal kettle in a certain proportion; (5) Add deionized water to the hydrothermal reactor at a solid-liquid ratio of 1:40-70 to form a mixed solution; (6) reacting the mixed solution in step (5) at 180-400°C for 6-30 h while maintaining mechanical stirring during the process, and washing with deionized water and drying after the reaction to obtain a lithium titanate precursor; (7) The lithium titanate precursor obtained in step (6) is calcined in air at 300-900°C for 1-8 h. After the reaction is completed, nano-lithium titanate powder can be obtained by grinding.
[0005] Preferably, the concentration of the oxalic acid solution in step (1) is 1-10 mol / L, and the solid-liquid ratio of the oxalic acid solution to the scrapped denitration catalyst powder is 1:5-20 g / ml.
[0006] Preferably, the alkali solution in step (2) is one of sodium hydroxide and potassium hydroxide or a mixture thereof, with a concentration of 10-20 mol / L, and the solid-liquid ratio of the alkali solution to the acid leaching residue is 1:5-20 g / mL.
[0007] Preferably, the acid solution in step (3) is one of sulfuric acid, nitric acid, oxalic acid, and formic acid, with a concentration of 2 to 15 mol / L, and the solid-liquid ratio of the acid solution to the titanate powder is 1:5 to 20 g / mL.
[0008] Preferably, the metatitanate powder obtained in step (3) has a purity of 90.2-99.5% as measured by XRF.
[0009] Preferably, the lithium source in step (4) is any one or more of lithium hydroxide, lithium carbonate, and lithium acetate, and the molar ratio of the lithium source to the Li / Ti in titanic acid is 4 to 8:1.
[0010] Preferably, the rotation speed of the mechanical stirring in step (6) is 250~800 rpm.
[0011] Preferably, the drying in step (6) is vacuum drying at 50-120° C. for 12-20 h.
[0012] Preferably, the content of the nano-lithium titanate powder synthesized in step (7) is 86.5-100% as determined by XRD.
[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses metatitanic acid, recovered from waste denitration catalysts, as the titanium source to synthesize nano-lithium titanate. This process boasts a fast reaction rate, high product purity, and uniform particle size. The resulting metatitanic acid has a purity of 90.2-99.5%, and the synthesized nano-lithium titanate has a content of 86.5-100%. Furthermore, the present invention can significantly reduce raw material costs, effectively reduce mineral resource extraction, and achieve energy conservation and carbon reduction. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 This is an SEM image of nano-lithium titanate synthesized in Example 1 of the present invention.
[0015] Figure 2 This is the XRD pattern of nano-lithium titanate synthesized in Example 1 of the present invention.
[0016] Figure 3 This is the XRD pattern of nano-lithium titanate synthesized in Example 2 of the present invention.
[0017] Figure 4 This is the XRD pattern of nano-lithium titanate synthesized in Example 3 of the present invention.
[0018] Figure 5 This is the XRD pattern of nano-lithium titanate synthesized in Example 4 of the present invention.
[0019] Figure 6 This is the XRD pattern of nano-lithium titanate synthesized in Example 5 of the present invention. DETAILED DESCRIPTION
[0020] The present invention is described in more detail below through specific embodiments. Example
[0021] A method for synthesizing nano-lithium titanate comprises the following steps: (1) An oxalic acid solution with a concentration of 1 mol / L was mixed with the scrapped denitration catalyst powder at a solid-liquid ratio of 1:10 g / mL, and the mixture was reacted at 100°C for 3 h with mechanical stirring. After the reaction, the acid leaching residue was filtered, washed, and dried. (2) A sodium hydroxide solution with a concentration of 16 mol / L was mixed with the acid leaching residue at a solid-liquid ratio of 1:10 g / mL, and then added to a microscale reactor to achieve sufficient mixing of the materials. The mixture was then added to a closed reactor and reacted at 150°C for 10 h with mechanical stirring. After the reaction, solid titanate powder was obtained by filtration, washing, and drying. (3) Sulfuric acid with a concentration of 2 mol / L was mixed with the solid titanate powder of step (2) at a solid-liquid ratio of 1:10 g / mL, and heated at 70°C for 4 h while maintaining mechanical stirring during the process. After cooling, the mixture was filtered, washed, and dried to obtain metatitanate powder; (4) adding lithium hydroxide and the titanate powder described in step (3) into a hydrothermal kettle at a Li / Ti molar ratio of 6:1; (5) Deionized water was added to the hydrothermal kettle at a solid-liquid ratio of 1:40 to form a mixed solution; (6) The mixed solution in step (5) was reacted at 180°C for 24 h, and mechanical stirring was maintained at 450 rpm. After the reaction, it was washed with deionized water and vacuum dried at 50°C for 20 h to obtain a lithium titanate precursor; (7) The lithium titanate precursor obtained in step (6) is calcined in air at 300°C for 8 h. After the reaction is completed, nano-lithium titanate powder can be obtained by grinding.
[0022] The purity of the metatitanate powder was 99.5% as tested by XRF. The lithium titanate powder was nano-scale material (such as Figure 1 As shown), the content of the above-mentioned nano-lithium titanate powder was 100% by XRD test (as shown Figure 2 shown). Example
[0023] A method for synthesizing nano-lithium titanate comprises the following steps: (1) 3 mol / L oxalic acid solution was mixed with scrapped denitration catalyst powder at a solid-liquid ratio of 1:20 g / mL, and reacted at 90 °C for 6 h with mechanical stirring. After the reaction, the acid leaching residue was filtered, washed, and dried. (2) A potassium hydroxide solution with a concentration of 10 mol / L was mixed with the acid leaching residue at a solid-liquid ratio of 1:20 g / mL, and then added to a microscale reactor to achieve sufficient mixing of the materials. The mixture was then added to a closed reactor and reacted at 100°C for 8 h with mechanical stirring. After the reaction, solid titanate powder was obtained by filtration, washing, and drying. (3) nitric acid with a concentration of 5 mol / L was mixed with the solid titanate powder described in step (2) at a solid-liquid ratio of 1:20 g / mL, and heated at 70°C for 8 h while maintaining mechanical stirring during the process. After cooling, the mixture was filtered, washed, and dried to obtain metatitanate powder; (4) adding lithium carbonate and the titanate powder described in step (3) into a hydrothermal kettle at a Li / Ti molar ratio of 4:1; (5) Deionized water was added to the hydrothermal reactor at a solid-liquid ratio of 1:50 to form a mixed solution; (6) The mixed solution in step (5) was reacted at 180°C for 30 h, and mechanical stirring was maintained at 250 rpm. After the reaction, it was washed with deionized water and vacuum dried at 70°C for 18 h to obtain a lithium titanate precursor; (7) The lithium titanate precursor obtained in step (6) is calcined at 450°C in air for 6 h. After the reaction is completed, nano-lithium titanate powder can be obtained by grinding.
[0024] The purity of the metatitanate powder was 90.2% as determined by XRF, and the content of the nano-lithium titanate powder was 86.5% as determined by XRD. Figure 3 shown). Example
[0025] A method for synthesizing nano-lithium titanate comprises the following steps: (1) A 5 mol / L oxalic acid solution was mixed with the scrapped denitration catalyst powder at a solid-liquid ratio of 1:15 g / mL, and the mixture was reacted at 100 °C for 4 h with mechanical stirring. After the reaction, the residue was filtered, washed, and dried to obtain the acid leaching residue. (2) A sodium hydroxide solution with a concentration of 10 mol / L was mixed with the acid leaching residue at a solid-liquid ratio of 1:15 g / mL, and then added to a microscale reactor to achieve sufficient mixing of the materials. The mixture was then added to a closed reactor and reacted at 120°C for 5 h with mechanical stirring. After the reaction, solid titanate powder was obtained by filtration, washing, and drying. (3) Sulfuric acid with a concentration of 8 mol / L was mixed with the solid titanate powder of step (2) at a solid-liquid ratio of 1:15 g / mL, and heated at 80°C for 5 h while maintaining mechanical stirring during the process. After cooling, the mixture was filtered, washed, and dried to obtain metatitanate powder; (4) adding lithium hydroxide and the titanate powder described in step (3) into a hydrothermal kettle at a Li / Ti molar ratio of 6:1; (5) Deionized water was added to the hydrothermal kettle at a solid-liquid ratio of 1:55 to form a mixed solution; (6) The mixed solution in step (5) was reacted at 300°C for 24 h, and mechanical stirring was maintained at 450 rpm. After the reaction, it was washed with deionized water and vacuum dried at 90°C for 16 h to obtain a lithium titanate precursor; (7) The lithium titanate precursor obtained in step (6) is calcined at 600°C in air for 4.5 h. After the reaction is completed, nano-lithium titanate powder can be obtained by grinding.
[0026] The purity of the metatitanate powder was 94.5% as determined by XRF, and the content of the nano-lithium titanate powder was 97.7% as determined by XRD. Figure 4 shown). Example
[0027] A method for synthesizing nano-lithium titanate comprises the following steps: (1) An oxalic acid solution with a concentration of 8 mol / L was mixed with the scrapped denitration catalyst powder at a solid-liquid ratio of 1:10 g / mL, and the mixture was reacted at 110 °C for 2 h with mechanical stirring. After the reaction, the acid leaching residue was filtered, washed, and dried. (2) A potassium hydroxide solution with a concentration of 15 mol / L was mixed with the acid leaching residue at a solid-liquid ratio of 1:10 g / mL, and then added to a microscale reactor to achieve sufficient mixing of the materials. The mixture was then added to a closed reactor and reacted at 135 °C for 3 h with mechanical stirring. After the reaction, solid titanate powder was obtained by filtration, washing, and drying. (3) 12 mol / L oxalic acid was mixed with the solid titanate powder of step (2) at a solid-liquid ratio of 1:10 g / mL, and heated at 90°C for 3 h while maintaining mechanical stirring during the process. After cooling, the mixture was filtered, washed, and dried to obtain metatitanate powder; (4) adding lithium carbonate and the titanate powder described in step (3) into a hydrothermal kettle at a Li / Ti molar ratio of 7:1; (5) Deionized water was added to the hydrothermal kettle at a solid-liquid ratio of 1:60 to form a mixed solution; (6) The mixed solution in step (5) was reacted at 320°C for 12 h, with mechanical stirring maintained at 550 rpm. After the reaction, it was washed with deionized water and vacuum dried at 105°C for 14 h to obtain a lithium titanate precursor. (7) The lithium titanate precursor obtained in step (6) is calcined at 750°C in air for 3 h. After the reaction is completed, nano-lithium titanate powder can be obtained by grinding.
[0028] The purity of the metatitanate powder was 96.8% as determined by XRF, and the content of the nano-lithium titanate powder was 95.3% as determined by XRD. Figure 5 shown). Example
[0029] A method for synthesizing nano-lithium titanate comprises the following steps: (1) A 10 mol / L oxalic acid solution was mixed with the scrapped denitration catalyst powder at a solid-liquid ratio of 1:5 g / mL, and the mixture was reacted at 120°C for 1 h with mechanical stirring. After the reaction, the acid leaching residue was filtered, washed, and dried. (2) A sodium hydroxide solution with a concentration of 20 mol / L was mixed with the acid leaching residue at a solid-liquid ratio of 1:5 g / mL, and then added to a microscale reactor to achieve sufficient mixing of the materials. The mixture was then added to a closed reactor and reacted at 150°C for 2 h with mechanical stirring. After the reaction, solid titanate powder was obtained by filtration, washing, and drying. (3) Formic acid having a concentration of 15 mol / L was mixed with the solid titanate powder of step (2) at a solid-liquid ratio of 1:5 g / mL, and heated at 100°C for 2 h while maintaining mechanical stirring during the process. After cooling, the mixture was filtered, washed, and dried to obtain metatitanate powder; (4) adding lithium acetate and the titanate powder described in step (3) into a hydrothermal kettle at a Li / Ti molar ratio of 8:1; (5) Deionized water was added to the hydrothermal reactor at a solid-liquid ratio of 1:70 to form a mixed solution; (6) The mixed solution in step (5) was reacted at 400°C for 6 h, and mechanical stirring was maintained at 800 rpm. After the reaction, it was washed with deionized water and vacuum dried at 120°C for 12 h to obtain a lithium titanate precursor; (7) The lithium titanate precursor obtained in step (6) is calcined at 900°C in air for 1 h. After the reaction is completed, nano-lithium titanate powder can be obtained by grinding.
[0030] The purity of the metatitanate powder was 98.3% as determined by XRF, and the content of the nano-lithium titanate powder was 93.4% as determined by XRD. Figure 6 shown).
[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for synthesizing nano-lithium titanate, characterized in that: The following steps are involved: (1) Mix the oxalic acid solution with the scrapped denitrification catalyst powder and react at 90-120°C for 1-6 hours with mechanical stirring. After the reaction is completed, filter, wash, and dry to obtain the acid leaching residue. (2) Alkaline solution and acid leaching residue are mixed and added to a microscale reactor to achieve full mixing of the materials. The mixture is then added to a closed reactor and reacted at 100-150 °C for 2-10 h. Mechanical stirring is maintained during the process. After the reaction is completed, solid titanate powder is obtained by filtration, washing, and drying. (3) mixing the acid solution with the solid titanate powder of step (2), heating at 70-100° C. for 2-8 h while maintaining mechanical stirring during the process, filtering after cooling, washing, and drying to obtain metatitanate powder; (4) adding the lithium source and the titanate powder described in step (3) into a hydrothermal kettle in a certain proportion; (5) Add deionized water to the hydrothermal reactor at a solid-liquid ratio of 1:40-70 to form a mixed solution; (6) reacting the mixed solution in step (5) at 180-400°C for 6-30 h while maintaining mechanical stirring during the process, and washing with deionized water and drying after the reaction to obtain a lithium titanate precursor; (7) The lithium titanate precursor obtained in step (6) is calcined in air at 300-900°C for 1-8 h. After the reaction is completed, nano-lithium titanate powder can be obtained by grinding.
2. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The concentration of the oxalic acid solution in step (1) is 1-10 mol / L, and the solid-liquid ratio of the oxalic acid solution to the scrapped denitration catalyst powder is 1:5-20 g / ml.
3. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The alkali solution in step (2) is one of sodium hydroxide and potassium hydroxide or a mixture thereof, with a concentration of 10-20 mol / L, and the solid-liquid ratio of the alkali solution to the acid leaching residue is 1:5-20 g / mL.
4. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The acid solution in step (3) is one of sulfuric acid, nitric acid, oxalic acid, and formic acid, with a concentration of 2 to 15 mol / L, and the solid-liquid ratio of the acid solution to the titanate powder is 1:5 to 20 g / mL.
5. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The metatitanic acid powder obtained in step (3) was tested by XRF and the purity was 90.2~99.5%.
6. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The lithium source in step (4) is any one or more of lithium hydroxide, lithium carbonate, and lithium acetate, and the molar ratio of the lithium source to the Li / Ti in titanic acid is 4 to 8:
1.
7. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The rotation speed of the mechanical stirring in step (6) is 250~800 rpm.
8. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The drying in step (6) is vacuum drying at 50-120°C for 12-20 h.
9. The method for synthesizing nano-lithium titanate according to claim 1, wherein: The content of the nano-lithium titanate powder synthesized in step (7) is 86.5~100% as determined by XRD.