Preparation method and application of mgfe2o4 / coal gasification fine slag composite material

Abstract

The application discloses a preparation method and application of MgFe2O4 / coal gasification fine slag composite material, a divalent magnesium source and a trivalent iron source which are soluble in ethylene glycol are dissolved in ethylene glycol according to a mass ratio of 1:2 to obtain solution A; 50mL-70mL of the solution A is taken, then 0.4g-0.6g of cetyltrimethylammonium bromide and 0.5g-0.7g of coal gasification fine slag are added, and the mixture is uniformly ultrasonically dispersed to obtain solution B; alkali liquor is gradually added into the solution B, and stirring is continuously carried out in the process of adding the alkali liquor; when the pH value of the solution B reaches 10.5-11.5, the stirring is stopped; then the obtained mixture is placed into a 100mL high-pressure reaction kettle, is heated to 160 DEG C-190 DEG C in a sealed mode, and is kept for 10h-15h; then the mixture is cooled; and the obtained precipitate is washed and dried to obtain the MgFe2O4 / coal gasification fine slag composite material. The application overcomes the defects of the prior art, realizes the resource utilization of waste coal gasification fine slag, and effectively reduces the preparation cost of the electromagnetic wave absorbing material.

Description

Technical Field

[0001] This invention relates to the technical field of new material preparation methods, specifically to the preparation method and application of MgFe2O4 / coal gasification fine slag composite materials. Background Technology

[0002] With technological advancements and the widespread application of microwave technology, the use of electromagnetic waves in wireless communication and high-frequency circuits has become increasingly common, resulting in the ubiquitous presence of electromagnetic waves of various intensities and frequencies. The resulting electromagnetic pollution and interference pose potential threats to human health, the operation of precision instruments, and information security. Current technologies primarily utilize expensive raw materials (such as graphene and rare earth metals) to prepare electromagnetic wave absorbing materials, and the entire preparation process is relatively complex and costly. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing MgFe2O4 / coal gasification fine slag composite material and its application, overcoming the shortcomings of the prior art.

[0004] To solve the above problems, the technical solution adopted in the preparation method of the MgFe2O4 / coal gasification fine slag composite material of the present invention is as follows:

[0005] The preparation method of MgFe2O4 / coal gasification fine slag composite material includes the following steps:

[0006] A solution A is obtained by dissolving a divalent magnesium source and a trivalent iron source, both soluble in ethylene glycol, in ethylene glycol at a molar ratio of 1:2.

[0007] Take 50mL-70mL of solution A, then add 0.4g-0.6g of hexadecyltrimethylammonium bromide and 0.5g-0.7g of coal gasification fine slag, and disperse evenly by ultrasonication to obtain solution B;

[0008] Add alkali solution dropwise to solution B while continuously stirring. When the pH of solution B reaches 10.5-11.5, stop stirring. Then, place the resulting mixture in a 100mL high-pressure reactor, seal it, heat it to 160℃-190℃, and keep it at that temperature for 10-15 hours. Then, cool it, wash and dry the resulting precipitate to obtain the MgFe2O4 / coal gasification fine slag composite material.

[0009] The divalent magnesium source is MgCl2·6H2O, and the trivalent iron source is FeCl3·6H2O.

[0010] The concentration of divalent magnesium source in solution A is 30 mmol / L-70 mmol / L.

[0011] The alkaline solution is a sodium hydroxide solution with a concentration of 1 mmol / L to 3 mmol / L.

[0012] In the MgFe2O4 / coal gasification fine slag composite material, MgFe2O4 nanoparticles are uniformly composited on the surface of the layered coal gasification fine slag.

[0013] The size range of MgFe2O4 nanoparticles is 5-10 nm.

[0014] The MgFe2O4 / coal gasification fine slag composite material prepared by this invention can be applied to microwave absorbing materials.

[0015] Compared with the prior art, the implementation effects of the present invention are as follows:

[0016] 1. This invention, through the design of the preparation method of MgFe2O4 / coal gasification fine slag composite material and the selection of raw materials, controls the particle size of MgFe2O4 in the prepared composite material, effectively avoids the problem of MgFe2O4 agglomeration during the preparation of MgFe2O4 / coal gasification fine slag composite material, improves the uniformity of composite material, and simplifies the preparation process.

[0017] 2. This invention designs a MgFe2O4 / coal gasification fine slag composite material, which utilizes the coal gasification fine slag from coal gasification waste combined with magnetic MgFe2O4 nanoparticles to enable the MgFe2O4 / coal gasification fine slag composite material to generate excellent electromagnetic wave absorption capacity, thereby realizing the resource utilization of waste coal gasification fine slag and effectively reducing the preparation cost of electromagnetic wave absorbing materials. Attached Figure Description

[0018] Figure 1 The X-ray diffraction patterns of the MgFe2O4 / coal gasification fine slag composite materials in Examples 4-6 are shown.

[0019] Figure 2 The images are scanning electron microscope (SEM) images of the MgFe2O4 / coal gasification fine slag composite materials of Examples 4-6, where a and d are SEM images of S1, b and e are SEM images of S1, and c and f are SEM images of S1.

[0020] Figure 3 This is a transmission electron microscope image of S2;

[0021] Figure 4 The electromagnetic wave loss capability diagram for S1 is shown.

[0022] Figure 5 The electromagnetic wave loss capability diagram for S2 is shown.

[0023] Figure 6 This is a diagram showing the electromagnetic wave loss capability of S3. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The coal gasification slag used in this invention has a carbon content of 53.62 wt%, a volatile matter content of 3.33 wt%, and an inorganic matter content of 43.05 wt%. Its main inorganic components are:

[0026]

[0027] Example 1

[0028] MgCl₂·6H₂O and FeCl₃·6H₂O were dissolved in ethylene glycol at a molar ratio of 1:2 to obtain solution A, in which MgCl₂·6H₂O was dissolved. 2+ The concentration of the solution was 30 mmol / L. 50 mL of solution A was taken, and then 0.4 g of hexadecyltrimethylammonium bromide and 0.5 g of coal gasification fine slag were added. After ultrasonic dispersion, solution B was obtained. A sodium hydroxide solution with a concentration of 1 mmol / L was gradually added dropwise to solution B. The mixture was stirred continuously during the dropwise addition of sodium hydroxide solution. When the pH value of solution B reached 9, the stirring was stopped. The resulting mixture was then placed in a 100 mL high-pressure reactor, sealed and heated to 160 °C, and kept at that temperature for 15 h. After cooling, the precipitate was washed and dried to obtain the MgFe2O4 / coal gasification fine slag composite material.

[0029] Example 2

[0030] MgCl₂·6H₂O and FeCl₃·6H₂O were dissolved in ethylene glycol at a molar ratio of 1:2 to obtain solution A, in which MgCl₂·6H₂O was dissolved. 2+ The concentration of the solution was 70 mmol / L. 70 mL of solution A was taken, and then 0.6 g of hexadecyltrimethylammonium bromide and 0.7 g of coal gasification fine slag were added. After ultrasonic dispersion, solution B was obtained. A sodium hydroxide solution with a concentration of 3 mmol / L was gradually added dropwise to solution B. The mixture was stirred continuously during the addition of sodium hydroxide solution. When the pH value of solution B reached 11, the stirring was stopped. The resulting mixture was then placed in a 100 mL high-pressure reactor, sealed and heated to 190 °C, and kept at that temperature for 10 h. After cooling, the precipitate was washed and dried to obtain the MgFe2O4 / coal gasification fine slag composite material.

[0031] Example 3

[0032] MgCl₂·6H₂O and FeCl₃·6H₂O were dissolved in ethylene glycol at a molar ratio of 1:2 to obtain solution A, in which MgCl₂·6H₂O was dissolved. 2+ The concentration of the solution was 60 mmol / L. 70 mL of solution A was taken, and then 0.55 g of hexadecyltrimethylammonium bromide and 0.65 g of coal gasification fine slag were added. After ultrasonic dispersion, solution B was obtained. A 2 mmol / L sodium hydroxide solution was gradually added dropwise to solution B, and the mixture was stirred continuously during the addition of sodium hydroxide solution. When the pH value of solution B reached 10.5, the stirring was stopped. The resulting mixture was then placed in a 100 mL high-pressure reactor, sealed and heated to 170 °C, and kept at that temperature for 14 h. After cooling, the precipitate was washed and dried to obtain the MgFe2O4 / coal gasification fine slag composite material.

[0033] Example 4

[0034] MgCl₂·6H₂O and FeCl₃·6H₂O were dissolved in ethylene glycol at a molar ratio of 1:2 to obtain solution A, in which MgCl₂·6H₂O was dissolved. 2+ The concentration was 40 mmol / L; 60 mL of solution A was taken, and then 0.5 g of hexadecyltrimethylammonium bromide and 0.6 g of coal gasification fine slag were added. After ultrasonic dispersion, solution B was obtained; a sodium hydroxide solution with a concentration of 2 mmol / L was gradually added dropwise to solution B, and the mixture was stirred continuously during the process of adding sodium hydroxide solution. When the pH value of solution B reached 10, the stirring was stopped. The resulting mixture was then placed in a 100 mL high-pressure reactor, sealed and heated to 180 °C, and kept at that temperature for 12 h. After cooling, the precipitate was washed and dried to obtain the MgFe2O4 / coal gasification fine slag composite material, labeled as S1.

[0035] Example 5

[0036] The difference from Example 4 is that Mg 2+ The concentration was 50 mmol / L, and the MgFe2O4 / coal gasification fine slag composite material was obtained, labeled as S2.

[0037] Example 6

[0038] The difference from Example 4 is that Mg 2+ The concentration was 67 mmol / L, and the MgFe2O4 / coal gasification fine slag composite material was obtained, labeled as S3.

[0039] The crystal structure of the MgFe2O4 / coal gasification fine slag composites from Examples 4-6 was analyzed by X-ray diffraction in the range of 20°-80° at a scanning rate of 2° / min. The surface morphology, microstructure, and elemental distribution of the composites were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The elemental composition and chemical state of the composites were determined by X-ray photoelectron spectroscopy (XPS). The MgFe2O4 / coal gasification fine slag composites were mixed with paraffin wax at a mass ratio of 6:4 and pressed into rings (outer diameter 7.00 mm, inner diameter 3.04 mm) using a mold. The electromagnetic parameters of the MgFe2O4 / coal gasification fine slag composites were tested using a vector network analyzer in the frequency range of 2.0 GHz-18.0 GHz. The absorption capacity of electromagnetic waves was calculated based on the electromagnetic parameters using the following formula:

[0040]

[0041] Z in The input impedance is f, d, and c, which represent the frequency, matching layer thickness, and speed of light, respectively. μ r and ε r These are the material's magnetic permeability and dielectric constant, respectively.

[0042] The test results for Examples 4-6 are shown in Figures 1-6. Figure 1-2 As shown, the X-ray diffraction patterns of S1-S3 correspond to the standard card JCPDS#88-1936 for MgFe2O4, and MgFe2O4 nanoparticles are uniformly composited on the surface of coal gasification fine slag. This invention successfully prepared a MgFe2O4 / coal gasification fine slag composite material, and simultaneously combined with... Figure 3 It can be seen that the particle size range of the MgFe2O4 / coal gasification fine slag composite material prepared by this invention is 5-10 nm. Figure 4-6 The results demonstrate that the MgFe2O4 / coal gasification fine slag composite material prepared in this invention exhibits excellent loss capability for electromagnetic waves in the 8GHz-12GHz range. Specifically, the S2 composite material, with a fitted thickness of 2.1mm, shows an electromagnetic wave absorption capacity exceeding 90% in the frequency band (EAB) of 7.16GHz-10.94GHz, covering most of the X-band (8-12GHz) electromagnetic waves, demonstrating excellent electromagnetic wave absorption capability. Furthermore, the S3 composite material, with a fitted thickness of 1.6mm, exhibits a high maximum reflection loss value (RL) for electromagnetic waves. min It reached -71.33dB.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing MgFe2O4 / coal gasification fine slag composite material, characterized in that, Includes the following steps: A solution A is obtained by dissolving a divalent magnesium source and a trivalent iron source soluble in ethylene glycol in a molar ratio of 1:2 in ethylene glycol. Take 50 mL - 70 mL of solution A, then add 0.4 g - 0.6 g of hexadecyltrimethylammonium bromide and 0.5 g - 0.7 g of coal gasification fine slag, and disperse evenly by ultrasonication to obtain solution B; Add alkali solution dropwise to solution B while stirring continuously. When the pH value of solution B reaches 10.5-11.5, stop stirring. Then, place the resulting mixture in a 100mL high-pressure reactor, heat it to 160℃-190℃ in a sealed container, and keep it at that temperature for 10h-15h. Then, cool it, wash and dry the resulting precipitate to obtain the MgFe2O4 / coal gasification fine slag composite material. In the MgFe2O4 / coal gasification fine slag composite material, MgFe2O4 nanoparticles are uniformly composited on the surface of the layered coal gasification fine slag; the size range of MgFe2O4 nanoparticles in the MgFe2O4 / coal gasification fine slag composite material is 5-10 nm. The divalent magnesium source is MgCl2·6H2O, and the trivalent iron source is FeCl3·6H2O.

2. The preparation method of the MgFe2O4 / coal gasification fine slag composite material according to claim 1, characterized in that, The concentration of divalent magnesium source in solution A is 30 mmol / L-70 mmol / L.

3. The preparation method of the MgFe2O4 / coal gasification fine slag composite material according to claim 1, characterized in that, The alkaline solution is a sodium hydroxide solution with a concentration of 1 mmol / L to 3 mmol / L.

4. The application of the MgFe2O4 / coal gasification fine slag composite material prepared by the method according to any one of claims 1-3, characterized in that, Applications in microwave absorbing materials.

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