Preparation method and application of FexOy / BaTiO3 / C composite microwave absorbing material
By preparing FexOy/BaTiO3/C composite microwave absorption material, using waste toner and waste warm patch residue as raw materials, the problems of resource waste and environmental pollution are solved, and low-cost and inefficient composite preparation and microwave absorption performance are achieved.
Patent Information
- Application Number
- CN202510054530.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2025-05-13
AI Technical Summary
The prior art is difficult to effectively utilize waste toner and waste warm patch residue, resulting in waste of resources and environmental pollution.
By preparing FexOy/BaTiO3/C composite microwave absorption material, use waste toner and waste warm patch residue as the main raw materials, combine chemical substances such as barium acetate aqueous solution, tetrabutyl titanate and glacial acetic acid, and prepare composite materials with good microwave absorption properties through magnetic stirring, aging and roasting.
It realizes efficient recycling and utilization of waste toner and waste warm patch residue, and prepares low-cost composite microwave absorbing materials, which have excellent microwave absorption performance and can effectively alleviate the problem of electromagnetic radiation pollution.
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Figure CN119979120A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of solid waste recycling and microwave absorbing materials, and specifically relates to a Fe x O y / BaTiO 3 Preparation method and application of / C composite microwave absorbing material. Background Art
[0002] The rapid development of electronic and information technology has brought people a lot of convenience, but at the same time, more and more electromagnetic radiation has flooded people's living environment. Electromagnetic radiation pollution is a kind of energy flow pollution, which is invisible and intangible, and difficult to be perceived. The radiation elements have strong penetrating power. It will not only have a serious impact on the normal operation of electronic equipment, but also cause different degrees of physical, chemical and biological effects, causing damage to the environment, and it has potential harm to human health. Microwave absorbing materials can convert incident electromagnetic waves into heat energy or other forms of energy through their own loss mechanism, which can effectively solve the problem of electromagnetic radiation pollution and has attracted widespread attention from researchers.
[0003] The widespread use of electronic devices and products has led to a sharp increase in the amount of electronic waste, which has become one of the main problems facing today's society. In 2010, the global amount of electronic waste was 34 million tons. Since then, this figure has continued to grow at an average annual rate of 23 million tons, reaching a record high of 62 million tons by 2022. Toner is one of the electronic wastes generated by laser printers, copiers and fax machines. It is mainly composed of styrene-acrylate copolymer, polymethyl methacrylate, amorphous silica, pigment, polypropylene, wax, iron oxide, carbon black and other additives such as leveling agents, charging agents and magnetic materials. The waste toner particles are small in size and will be suspended in the air for a period of time after being discharged into the environment, which has an adverse effect on human health. In addition, the composition and performance of waste toner have changed greatly after use. Even if it is recycled, it is difficult to refill the ink cartridge for use. It is worth noting that waste toner still contains a large amount of fixed carbon and magnetic iron oxide, and it is urgent to develop new processes to recycle waste toner.
[0004] The heating pad is a portable and efficient heating product. The average temperature during use can reach 53 ℃ and the duration is 10-12 hours. It has a good effect on preventing frostbite in winter and relieves pain in the waist, shoulders, stomach, joints, etc. The raw materials of the heating pad are mainly iron, vermiculite, activated carbon, inorganic salts, water, etc. The basic content of iron powder is between 68% and 85%, and its heating principle is the oxidation and heat release of iron. With the development of related technologies, the output of heating pads is increasing year by year, and the amount of discarded heating pads has increased dramatically. At present, the treatment of discarded heating pads has not attracted everyone's attention. Only some areas have carried out pilot projects to try to recycle them for deodorization, moisture-proofing and other treatments before reuse, but the effect is not ideal. Therefore, directly discarding discarded heating pads not only pollutes the environment, but also causes waste of resources. Developing new utilization methods for the comprehensive utilization of discarded heating pads can not only improve the resource utilization efficiency of discarded heating pads, but also meet the requirements of sustainable development and help strengthen environmental protection.
[0005] As we all know, barium titanate (BaTiO 3 ) is a typical perovskite ceramic material with excellent ferroelectricity, piezoelectricity, insulation and high dielectric constant. It is currently widely used in ferroelectric field effect transistors, storage devices, piezoelectric sensors and other electronic components. At the same time, the excellent properties of barium titanate enable it to have a good attenuation effect on electromagnetic waves under the action of electromagnetic fields, and it is a good dielectric loss-type absorbing material. However, the loss mechanism of single barium titanate is relatively single, and its absorbing performance is poor, which cannot meet the needs of actual application environments. On the other hand, ferrite magnetic powder has high resistivity and magnetic permeability, low price, and simple preparation method. It is a typical magnetic loss material. If barium titanate is compounded with ferrite, it can not only expand the electromagnetic loss mechanism of the material, but also improve the absorbing performance.
[0006] In summary, the rational development and utilization of waste toner or waste heating pad residues to prepare Fe x O y / BaTiO 3 / C composite microwave absorbing material can not only effectively alleviate the ecological environmental pressure caused by the random discharge of waste toner or waste heating pads, but also reduce the production cost of composite absorbing materials, realize the transformation of solid waste into high value-added products, and improve the recycling level of solid waste resources. Summary of the invention
[0007] The main purpose of the present invention is to overcome the shortcomings of the prior art and solve the problem of resource utilization of waste toner and waste heating pad residues. The present invention provides a Fe x O y / BaTiO 3The preparation method and application of / C composite microwave absorbing materials provide new ideas for the high value-added and large-scale application of solid waste, and at the same time realize the low-cost preparation of composite microwave absorbing materials.
[0008] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: Fe x O y / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. After crushing and ball-milling the solid waste, the solid waste is sieved through a 100-300 mesh standard sieve, and the sieved solid waste powder is placed in an oven for drying at a temperature of 60° C. to 100° C. for a drying time of 4 to 8 hours, and is reserved for use in a subsequent step; the solid waste is waste toner or waste heating pad residue; S2. Prepare a barium acetate aqueous solution with a mass concentration of 25% to 45%, which will be used in the next step; S3. First, tetrabutyl titanate, glacial acetic acid, and anhydrous ethanol are mixed uniformly in a volume ratio of (1-3):(2-12):(0-10) to obtain a mixed solution; secondly, the barium acetate aqueous solution prepared in step S2 is added dropwise to the mixed solution, wherein the volume of the barium acetate aqueous solution accounts for 10%-30% of the volume of the mixed solution, to obtain a sol; thirdly, the solid waste powder dried in step S1 is weighed and added to the sol, wherein the mass ratio of the solid waste powder to the tetrabutyl titanate in the sol is (1-2):(1-10), and the mixture is mixed uniformly by magnetic stirring; finally, a gel is obtained after aging; S4. First, the gel prepared in step S3 is placed in an oven for drying at a temperature of 60°C to 120°C for a drying time of 6 to 12 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature is 400℃~1000℃ in a constant temperature atmosphere for 2h, and then cooled to room temperature to obtain Fe x O y / BaTiO 3 / C composite microwave absorbing material.
[0009] Furthermore, the chemical composition and mass percentage of the waste toner are: Fe 2 O 3 :55.79%,SiO 2 : 17.32%, ZnO: 6.95%, C: 10.81%, CuO: 5.72%, CaO: 3.41%; the composition and mass percentage of the waste heating pad residue are: Fe 2 O 3 :63.3 %, C:22.2 %, SiO 2:8.6 %,Al 2 O 3 :3.5%, CaO:2.4%.
[0010] Furthermore, in step S3, the rotation speed of the magnetic stirring is 100-400 r / min.
[0011] Furthermore, in the step S3, the aging is carried out at room temperature, and the aging time is 8-24 hours.
[0012] The Fe prepared by the above-mentioned preparation method x O y / BaTiO 3 Application of / C composite microwave absorbing materials in microwave absorption process.
[0013] Furthermore, the Fe x O y / BaTiO 3 The effective phase for microwave absorption in the / C composite microwave absorbing material is Fe x O y 、BaTiO 3 and C, the Fe x O y Fe or Fe 3 O 4 ; Among them, Fe x O y As a magnetic component, BaTiO 3 and C as dielectric components.
[0014] Further, in the Fe x O y / BaTiO 3 In the composite microwave absorbing material, the dielectric component BaTiO 3 Wrapped in the magnetic component Fe x O y Outside the composite absorbing material, the dielectric component C is evenly distributed in the composite absorbing material.
[0015] The beneficial effects of the present invention are: 1. The main raw material used in the present invention is solid waste (waste toner or waste heating pad residue), which is effectively recycled to prepare Fe x O y / BaTiO 3 / C composite microwave absorbing material, the preparation process is simple, which helps to realize the low-cost preparation of microwave absorbing materials; 2. In N 2 During the baking process in the atmosphere, Fe 2 O3 Carbothermal reduction reaction with C yields Fe 3 O 4 or Fe, without the need to add additional carbon source; the generated Fe 3 O 4 Or Fe as magnetic component, BaTiO 3 and C as dielectric components, the magnetic component and the dielectric component work together to optimize the microwave absorption performance of the composite material; 3. BaTiO 3 The dielectric properties of carbon materials can be adjusted, and together with the remaining carbon, dielectric loss can be provided to synergistically enhance the microwave absorption performance of the material. 3 With excellent thermal stability, BaTiO 3 Coating on the surface of the magnetic component can improve the performance of the composite material in high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 The Fe / BaTiO 3 / C microwave reflection loss curve of composite microwave absorbing material; Figure 2 The Fe 3 O 4 / BaTiO 3 Raman spectrum of / C composite microwave absorbing material; Figure 3 The Fe / BaTiO 3 X-ray diffraction spectrum of / C composite microwave absorbing material.
[0017] Figure 4 The Fe prepared from the waste heating pad residue in Example 5 3 O 4 / BaTiO 3 / C microwave reflection loss curve of composite microwave absorbing material; Figure 5 The Fe / BaTiO prepared from the waste heating pad residue in Example 6 3 XRD spectrum of / C composite microwave absorbing material; Figure 6 The Fe prepared from the waste heating pad residue in Example 7 3 O 4 / BaTiO 3 Raman spectrum of / C composite microwave absorbing material. DETAILED DESCRIPTION
[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Example 1
[0019] Fe / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. Weigh the waste toner and sieve it through a 100-mesh standard sieve. Dry the sieved waste toner in an oven at a drying temperature of 100° C. for 8 hours and keep it for later use. The chemical composition and mass percentage of the waste toner are as follows: Fe 2 O 3 :55.79%,SiO 2 : 17.32%, ZnO: 6.95%, C: 10.81%, CuO: 5.72%, CaO: 3.41% S2. Prepare a 37.5% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol were mixed uniformly in a volume ratio of 3:10:2 to obtain a mixed solution A. Secondly, 3.65 mL of the barium acetate aqueous solution prepared in step S2 was added dropwise to the mixed solution A to obtain a sol B. Thirdly, the waste toner dried in step S1 was weighed and added to the sol B, the mass ratio of the waste toner to the tetrabutyl titanate in the sol B was 1:1, and the mixture was mixed uniformly by magnetic stirring at a speed of 100-200 r / min. Finally, the mixture was aged at room temperature for 10 hours to obtain a gel C. S4. First, the gel C prepared in step S3 is placed in an oven for drying at a temperature of 100° C. for a drying time of 6 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature was 900℃ and the sintering time was 2h. Then the sintering temperature was cooled to room temperature to obtain Fe / BaTiO 3 / C composite microwave absorbing material.
[0020] The Fe / BaTiO prepared by the preparation method described in Example 1 3 Application of / C composite microwave absorbing materials in microwave absorption process. The effective phases for microwave absorption are Fe, BaTiO 3 and C, with Fe as the magnetic component, BaTiO 3 and C as dielectric components; and the dielectric component BaTiO 3 Wrapped on the outside of the magnetic component Fe, the dielectric component C is evenly distributed in the composite absorbing material.
[0021] like Figure 1 As shown, the Fe / BaTiO 3When the / C composite microwave absorbing material is used in the microwave absorption process, when the coating thickness is 1.5 mm, its effective bandwidth is 4.2 GHz and the minimum reflection loss value is -35.6 dB. Example 2
[0022] Fe 3 O 4 / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. Weigh the waste toner and sieve it through a 100-mesh standard sieve. Dry the sieved waste toner in an oven at 80°C for 10 hours for later use. The chemical composition and mass percentage of the waste toner are as follows: Fe 2 O 3 :55.79%,SiO 2 : 17.32%, ZnO: 6.95%, C: 10.81%, CuO: 5.72%, CaO: 3.41% S2. Prepare a 37.5% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol were mixed uniformly in a volume ratio of 3:10:2 to obtain a mixed solution A. Secondly, 3.65 mL of the barium acetate aqueous solution prepared in step S2 was added dropwise to the mixed solution A to obtain a sol B. Thirdly, the waste toner dried in step S1 was weighed and added to the sol B, the mass ratio of the waste toner to the tetrabutyl titanate in the sol B was 1:2, and the mixture was mixed uniformly by magnetic stirring at a speed of 200-300 r / min. Finally, the gel C was obtained after aging at room temperature for 15 h. S4. First, the gel C prepared in step S3 is placed in an oven for drying at a temperature of 80° C. for a drying time of 8 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature is 700℃ and the sintering time is 2h. Then the sintering temperature is cooled to room temperature to obtain Fe 3 O 4 / BaTiO 3 / C composite microwave absorbing material.
[0023] The Fe prepared by the preparation method described in Example 2 3 O 4 / BaTiO 3 Application of / C composite microwave absorbing materials in microwave absorption process, the effective phase for microwave absorption is Fe 3 O 4 、BaTiO 3 and C, of which Fe3 O 4 As a magnetic component, BaTiO 3 and C as dielectric components; and the dielectric component BaTiO 3 Wrapped in the magnetic component Fe 3 O 4 Outside the composite absorbing material, the dielectric component C is evenly distributed in the composite absorbing material.
[0024] Depend on Figure 2 It can be seen that the Fe 3 O 4 / BaTiO 3 The Raman spectrum of the / C composite microwave absorbing material has D peak and G peak. After the carbothermal reduction reaction, Fe 3 O 4 / BaTiO 3 There is still excess carbon inside the / C composite material, which can serve as a dielectric component to supplement the dielectric loss and improve the microwave loss capacity of the material. Example 3
[0025] Fe / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. Weigh the waste toner and sieve it through a 100-mesh standard sieve. Dry the sieved waste toner in an oven at 80°C for 10 hours for later use. The chemical composition and mass percentage of the waste toner are as follows: Fe 2 O 3 :55.79%,SiO 2 : 17.32%, ZnO: 6.95%, C: 10.81%, CuO: 5.72%, CaO: 3.41% S2. Prepare a 37.5% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol were mixed uniformly in a volume ratio of 3:9:4 to obtain a mixed solution A. Secondly, 3.65 mL of the barium acetate aqueous solution prepared in step S2 was added dropwise to the mixed solution A to obtain a sol B. Thirdly, the waste toner dried in step S1 was weighed and added to the sol B, the mass ratio of the waste toner to the tetrabutyl titanate in the sol B was 1:2, and the mixture was mixed uniformly by magnetic stirring at a speed of 250-350 r / min. Finally, the gel C was obtained after aging at room temperature for 12 h. S4. First, the gel C prepared in step S3 is placed in an oven for drying at a temperature of 80° C. for a drying time of 8 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2The sintering temperature was 900℃ and the sintering time was 2h. Then the sintering temperature was cooled to room temperature to obtain Fe / BaTiO 3 / C composite microwave absorbing material.
[0026] The Fe / BaTiO prepared by the preparation method described in Example 3 3 Application of / C composite microwave absorbing materials in microwave absorption process. The effective phases for microwave absorption are Fe, BaTiO 3 and C, with Fe as the magnetic component, BaTiO 3 and C as dielectric components; and the dielectric component BaTiO 3 Wrapped on the outside of the magnetic component Fe, the dielectric component C is evenly distributed in the composite absorbing material.
[0027] Depend on Figure 3 It can be seen that the Fe / BaTiO 3 The X-ray diffraction spectrum of the composite microwave absorbing material has BaTiO 3 Characteristic peaks, that is, BaTiO with good crystallinity can be obtained through sol-gel process 3 Crystal phase. Example 4
[0028] Fe 3 O 4 / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. Weigh the waste toner and sieve it through a 100-mesh standard sieve. Dry the sieved waste toner in an oven at 80°C for 10 hours for later use. The chemical composition and mass percentage of the waste toner are as follows: Fe 2 O 3 :55.79%,SiO 2 : 17.32%, ZnO: 6.95%, C: 10.81%, CuO: 5.72%, CaO: 3.41% S2. Prepare a 40% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol were mixed uniformly in a volume ratio of 2:10:3 to obtain a mixed solution A; secondly, 4.38 mL of the barium acetate aqueous solution prepared in step S2 was measured and added dropwise to the mixed solution A to obtain a sol B; thirdly, the waste toner dried in step S1 was weighed and added to the sol B, the mass ratio of the waste toner to the tetrabutyl titanate in the sol B was 1:0.5, and the mixture was mixed uniformly by magnetic stirring at a speed of 300-400 r / min; finally, the mixture was aged at room temperature for 18 h to obtain a gel C; S4. First, the gel C prepared in step S3 is placed in an oven for drying at a temperature of 80° C. for a drying time of 8 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature is 700℃ and the sintering time is 2h. Then the sintering temperature is cooled to room temperature to obtain Fe 3 O 4 / BaTiO 3 / C composite microwave absorbing material. Example 5
[0029] Fe 3 O 4 / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. The waste heating pad residue is crushed, ball-milled and sieved through a 120-mesh standard sieve. The sieved waste heating pad residue powder is placed in an oven and dried at a temperature of 80°C for 5 hours for subsequent use. The composition and mass percentage of the waste heating pad residue are as follows: Fe 2 O 3 :63.3 %, C:22.2 %, SiO 2 :8.6 %,Al 2 O 3 : 3.5%, CaO: 2.4%; S2. Prepare a 30% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol are mixed uniformly in a volume ratio of 1:2:4 to obtain a mixed solution; secondly, the barium acetate aqueous solution prepared in step S2 is measured and added dropwise to the mixed solution, the volume of the barium acetate aqueous solution accounts for 25% of the volume of the mixed solution, to obtain a sol; thirdly, the waste heating pad residue powder after drying in step S1 is weighed and added to the sol, the mass ratio of the waste heating pad residue powder to the tetrabutyl titanate in the sol is 1:3, and the mixture is mixed uniformly by magnetic stirring at a speed of 200-300 r / min; finally, the gel is obtained after aging at room temperature for 12 hours; S4. First, the gel prepared in step S3 is placed in an oven for drying at a temperature of 100° C. for 10 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature is 700℃ and the sintering time is 2h. Then the sintering temperature is cooled to room temperature to obtain Fe 3 O 4 / BaTiO 3 / C composite microwave absorbing material.
[0030] The Fe prepared by the preparation method described in Example 5 3 O 4 / BaTiO 3 Application of / C composite microwave absorbing materials in microwave absorption process, the effective phase for microwave absorption is Fe 3 O 4 、BaTiO 3 and C, among which Fe 3 O 4 As a magnetic component, BaTiO 3 and C as dielectric components, and the dielectric component BaTiO 3 Wrapped in the magnetic component Fe 3 O 4 Outside the composite absorbing material, the dielectric component C is evenly distributed in the composite absorbing material.
[0031] like Figure 4 As shown, the Fe prepared in Example 5 3 O 4 / BaTiO 3 When the / C composite microwave absorbing material is used in the microwave absorption process, when the coating thickness is 4.0 mm, the minimum reflection loss is -46.2 GHz; when the coating thickness is 1.5 mm, its minimum reflection loss is -37.1 GHz, and the effective absorption bandwidth is 3.7 GHz. Example 6
[0032] Fe / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. The waste heating pad residue is crushed, ball-milled and then sieved through a 150-mesh standard sieve. The sieved waste heating pad residue powder is placed in an oven and dried at a temperature of 100°C for 6 hours for subsequent use. The composition and mass percentage of the waste heating pad residue are as follows: Fe 2 O 3 :63.3 %, C:22.2 %, SiO 2 :8.6 %,Al 2 O 3 : 3.5%, CaO: 2.4%; S2. Prepare a 35% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol are mixed uniformly in a volume ratio of 1:3:7 to obtain a mixed solution; secondly, the barium acetate aqueous solution prepared in step S2 is measured and added dropwise to the mixed solution, the volume of the barium acetate aqueous solution accounts for 20% of the volume of the mixed solution, to obtain a sol; thirdly, the waste heating pad residue powder after drying in step S1 is weighed and added to the sol, the mass ratio of the waste heating pad residue powder to the tetrabutyl titanate in the sol is 1:5, and the mixture is mixed uniformly by magnetic stirring at a speed of 200-300 r / min; finally, the gel is obtained after aging at room temperature for 20 hours; S4. First, the gel prepared in step S3 is placed in an oven for drying at a temperature of 80° C. for 10 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature was 900℃ and the sintering time was 2h. Then the sintering temperature was cooled to room temperature to obtain Fe / BaTiO 3 / C composite microwave absorbing material.
[0033] The Fe / BaTiO prepared by the preparation method described in Example 6 3 Application of / C composite microwave absorbing materials in microwave absorption process. The effective phases for microwave absorption are Fe, BaTiO 3 and C, among which Fe is the magnetic component, BaTiO 3 and C as dielectric components, and the dielectric component BaTiO 3 Wrapped on the outside of the magnetic component Fe, the dielectric component C is evenly distributed in the composite absorbing material.
[0034] like Figure 5 As shown, the Fe / BaTiO prepared in Example 6 3 The X-ray diffraction spectrum of the / C composite microwave absorbing material shows obvious BaTiO 3 characteristic peaks, indicating that BaTiO can be successfully prepared by this preparation method 3 . Example 7
[0035] Fe 3 O 4 / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. The waste heating pad residue is crushed, ball-milled and sieved through a 200-mesh standard sieve. The sieved waste heating pad residue powder is placed in an oven and dried at a temperature of 80°C for 8 hours for subsequent use. The composition and mass percentage of the waste heating pad residue are as follows: Fe 2 O 3 :63.3 %, C:22.2 %, SiO2 :8.6 %,Al 2 O 3 : 3.5%, CaO: 2.4%; S2. Prepare a 40% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol are mixed uniformly in a volume ratio of 1:4:9 to obtain a mixed solution; secondly, the barium acetate aqueous solution prepared in step S2 is measured and added dropwise to the mixed solution, and the volume ratio of the barium acetate aqueous solution to the mixed solution is 1:6 to obtain a sol; thirdly, the waste heating pad residue powder after drying in step S1 is weighed and added to the sol, and the mass ratio of the waste heating pad residue powder to the tetrabutyl titanate in the sol is 1:6, and the mixture is mixed uniformly by magnetic stirring at a speed of 300-400 r / min; finally, the gel is obtained after aging at room temperature for 15 hours; S4. First, the gel prepared in step S3 is placed in an oven for drying at a temperature of 80° C. for 10 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature is 700℃ and the sintering time is 2h. Then the sintering temperature is cooled to room temperature to obtain Fe 3 O 4 / BaTiO 3 / C composite microwave absorbing material.
[0036] The Fe prepared by the preparation method described in Example 7 3 O 4 / BaTiO 3 Application of / C composite microwave absorbing materials in microwave absorption process, the effective phase for microwave absorption is Fe 3 O 4 、BaTiO 3 and C, among which Fe 3 O 4 As a magnetic component, BaTiO 3 and C as dielectric components, and the dielectric component BaTiO 3 Wrapped in the magnetic component Fe 3 O 4 Outside the composite absorbing material, the dielectric component C is evenly distributed in the composite absorbing material.
[0037] like Figure 6 As shown, the Fe prepared in Example 7 3 O 4 / BaTiO 3 The Raman spectrum of the BaTiO composite microwave absorbing material shows obvious D and G peaks, indicating that some residual carbon still exists in the system after the carbothermal reduction reaction under the reaction conditions.3 Together they act as dielectric loss components. Example 8
[0038] Fe / BaTiO 3 The preparation method of the / C composite microwave absorbing material comprises the following steps: S1. The waste heating pad residue is crushed, ball-milled and sieved through a 200-mesh standard sieve. The sieved waste heating pad residue powder is placed in an oven and dried at a temperature of 100°C for 8 hours for subsequent use. The composition and mass percentage of the waste heating pad residue are as follows: Fe 2 O 3 :63.3 %, C:22.2 %, SiO 2 :8.6 %,Al 2 O 3 : 3.5%, CaO: 2.4%; S2. Prepare a 40% barium acetate aqueous solution for later use; S3. First, tetrabutyl titanate, glacial acetic acid and anhydrous ethanol are mixed uniformly in a volume ratio of 1:6:8 to obtain a mixed solution; secondly, the barium acetate aqueous solution prepared in step S2 is measured and added dropwise to the mixed solution, the volume of the barium acetate aqueous solution accounts for 12.5% of the volume of the mixed solution, to obtain a sol; thirdly, the waste heating pad residue powder after drying in step S1 is weighed and added to the sol, the mass ratio of the waste heating pad residue powder to the tetrabutyl titanate in the sol is 1:7, and the mixture is mixed uniformly by magnetic stirring at a speed of 250-350 r / min; finally, the gel is obtained after aging at room temperature for 20 hours; S4. First, the gel prepared in step S3 is placed in an oven for drying at a temperature of 100° C. for 10 hours to obtain a precursor dry gel; then, the precursor dry gel is placed in a tubular furnace at N 2 The sintering temperature was 900℃ and the sintering time was 2h. Then the sintering temperature was cooled to room temperature to obtain Fe / BaTiO 3 / C composite microwave absorbing material.
[0039] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.
Claims
1. A kind of Fe x O y The preparation method of / BaTiO3 / C composite microwave absorbing material is characterized in that: The following steps are involved: S1. After crushing and ball-milling the solid waste, the solid waste is sieved through a 100-300 mesh standard sieve, and the sieved solid waste powder is placed in an oven for drying at a temperature of 60° C. to 100° C. for a drying time of 4 to 8 hours, and is reserved for use in a subsequent step; the solid waste is waste toner or waste heating pad residue; S2. Prepare a barium acetate aqueous solution with a mass concentration of 25% to 45%, which will be used in the next step; S3. First, tetrabutyl titanate, glacial acetic acid, and anhydrous ethanol are mixed uniformly in a volume ratio of (1-3):(2-12):(0-10) to obtain a mixed solution; secondly, the barium acetate aqueous solution prepared in step S2 is added dropwise to the mixed solution, wherein the volume of the barium acetate aqueous solution accounts for 10%-30% of the volume of the mixed solution, to obtain a sol; thirdly, the solid waste powder dried in step S1 is weighed and added to the sol, wherein the mass ratio of the solid waste powder to the tetrabutyl titanate in the sol is (1-2):(1-10), and the mixture is mixed uniformly by magnetic stirring; finally, a gel is obtained after aging; S4. First, the gel prepared in step S3 is placed in an oven and dried at a temperature of 60°C to 120°C for 6 to 12 hours to obtain a precursor dry gel; Then, the precursor dry gel was placed in a tubular furnace and calcined at a constant temperature of 400°C to 1000°C in a N2 atmosphere for 2 h, and then cooled to room temperature to obtain Fe x O y / BaTiO3 / C composite microwave absorbing material.
2. A Fe according to claim 2 x O y The preparation method of / BaTiO3 / C composite microwave absorbing material is characterized in that: The chemical composition and mass percentage of the waste toner are: Fe2O3: 55.79%, SiO2: 17.32%, ZnO: 6.95%, C: 10.81%, CuO: 5.72%, CaO: 3.41%; the composition and mass percentage of the waste heating pad residue are: Fe2O3: 63.3%, C: 22.2%, SiO2: 8.6%, Al2O3: 3.5%, CaO: 2.4%.
3. A Fe according to claim 1 x O y The preparation method of / BaTiO3 / C composite microwave absorbing material is characterized in that: In the step S3, the rotation speed of the magnetic stirring is 100-400 r / min.
4. A Fe according to claim 1 x O y The preparation method of / BaTiO3 / C composite microwave absorbing material is characterized in that: In the step S3, the aging is carried out at room temperature, and the aging time is 8-24 hours.
5. Fe prepared by the preparation method as claimed in claim 1 x O y Application of / BaTiO3 / C composite microwave absorbing materials in microwave absorption process.
6. The use according to claim 5, characterized in that: The Fe x O y The effective phase for microwave absorption in the / BaTiO3 / C composite microwave absorbing material is Fe x O y , BaTiO3 and C, the Fe x O y Fe or Fe3O4; Among them, Fe x O y As a magnetic component, BaTiO3 and C serve as a dielectric component.
7. The use according to claim 6, characterized in that: In the Fe x O y In the / BaTiO3 / C composite microwave absorbing material, the dielectric component BaTiO3 is wrapped around the magnetic component Fe x O y Outside the composite absorbing material, the dielectric component C is evenly distributed in the composite absorbing material.