CN114496437A - Nuclear radiation resistant magnetic particle, preparation method thereof and nuclear radiation resistant magnetic liquid - Google Patents
Nuclear radiation resistant magnetic particle, preparation method thereof and nuclear radiation resistant magnetic liquid Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
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Abstract
The invention relates to the technical field of materials, in particular to a nuclear radiation resistant magnetic particle, a preparation method thereof and a nuclear radiation resistant magnetic liquid. The nuclear radiation resistant magnetic particle includes: the surface of the nano magnetic particle is coated by a mesoporous silica layer, wherein the mesoporous silica layer is loaded with barium sulfate. According to the invention, the mesoporous silica layer is coated on the surface of the nano magnetic particle by the surface in-situ synthesis method and barium sulfate is loaded, so that the prepared magnetic particle and magnetic liquid have good nuclear radiation resistance.
Description
Technical Field
The invention relates to the technical field of materials, in particular to a nuclear radiation resistant magnetic particle, a preparation method thereof and a nuclear radiation resistant magnetic liquid.
Background
Nuclear energy is one of the most important novel energy sources in the modern times, and is very important for relieving the increasingly serious energy crisis problem; however, the utilization of nuclear energy has inevitable problems, for example, the utilization of nuclear energy mainly uses nuclear power, nuclear power generating nuclear reactors often need circulating coolants, the coolants have the characteristics of high temperature, high pressure and strong radiation, and the like, and the leakage problem of the coolants needs to be strictly limited, wherein the most important point is the sealing of a nuclear reactor main pump. The existing commonly-used seal is a multi-stage mechanical seal, and although the seal has stable work, strong pressure resistance and wide application range, the leakage can be caused by uneven oil film distribution between end surfaces in the process of stopping and starting.
The magnetic liquid seal is a novel seal form, has the advantages of tight sealing, no measurable leakage rate, long service life, high reliability, no pollution and the like, and plays an irreplaceable important role in many industries. The magnetic liquid seal is combined with a mechanical seal, and the respective advantages of the mechanical seal and the magnetic liquid seal can be combined to realize zero-leakage sealing of the nuclear reactor main pump.
Disclosure of Invention
The present invention is based on the discovery and recognition by the inventors of the following facts and problems: nuclear radiation is hidden near a nuclear reactor, the aging of materials is accelerated, and the magnetic liquid is ineffective, but the existing nuclear radiation prevention measures are not ideal in effect and stability when the nuclear radiation is blocked by a pipe fitting plating layer or cement.
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the embodiment of the invention provides a nuclear radiation resistant magnetic particle and a preparation method thereof, and a nuclear radiation resistant magnetic liquid, wherein a mesoporous silica layer is coated on the surface of a nano magnetic particle through a surface in-situ synthesis method and barium sulfate is loaded, so that the prepared magnetic particle and the prepared magnetic liquid have good nuclear radiation resistance.
A nuclear radiation resistant magnetic particle according to an embodiment of the present invention includes: the surface of the nano magnetic particle is coated by a mesoporous silica layer, wherein the mesoporous silica layer is loaded with barium sulfate.
The nuclear radiation resistant magnetic particles according to the embodiments of the present invention bring advantages and technical effects: 1. in the embodiment of the invention, the mesoporous silica layer on the surface of the nano magnetic particle can load a large amount of barium sulfate, so that the nuclear radiation resistance of the magnetic particle is effectively improved; 2. under the condition that the magnetic performance of the nano magnetic particles is not influenced, the mesoporous silica layer increases the specific surface area of the magnetic particles, increases the contact area of a modifier and the surfaces of the nano magnetic particles, improves the modification capability of the nano magnetic particles, and is favorable for improving the dispersion degree and stability of magnetic liquid prepared subsequently; 3. the nuclear radiation resistant magnetic particles provided by the embodiment of the invention have high nuclear radiation resistance, good magnetic resistance and stability, and are easy to realize application in various fields.
The preparation method of the nuclear radiation resistant magnetic particles comprises the following steps:
a. coating: dispersing the nano magnetic particles, a pore-forming agent and alkali in a solvent, dropwise adding a silicon source, and carrying out sol-gelation reaction to obtain silicon dioxide-magnetic nano particles;
b. pore-forming: removing the pore-forming agent in the silica-magnetic nanoparticles to obtain mesoporous silica-magnetic nanoparticles;
c. loading: and dispersing the mesoporous silica-magnetic nanoparticles in a barium chloride solution for adsorption reaction, then adding a sulfate solution, and separating and washing precipitates to obtain the nuclear radiation resistant magnetic particles.
The preparation method of the nuclear radiation resistant magnetic particles according to the embodiment of the invention has the following advantages and technical effects: 1. according to the preparation method provided by the embodiment of the invention, the mesoporous silicon dioxide layer is coated on the surface of the magnetic nanoparticles by adopting a surface in-situ synthesis method, and then the barium sulfate is loaded on the mesoporous silicon dioxide layer by adopting a coprecipitation method, so that the loading capacity of the barium sulfate is greatly improved due to the high porosity of the mesoporous silicon dioxide layer, and the nuclear radiation resistance of the magnetic particles is effectively improved; 2. the mesoporous silica shell layer is coated on the surface of the magnetic nanoparticles, so that the magnetic performance of the magnetic nanoparticles is not influenced, the specific surface area of the particles is increased, the contact area of a modifier and the surface of the magnetic nanoparticles is increased, the modification capability of the magnetic nanoparticles is improved, and the dispersity and the stability of the magnetic liquid prepared subsequently are improved; 3. the nuclear radiation resistant magnetic particle provided by the embodiment of the invention has the advantages of simple preparation method, high efficiency, good magnetic saturation strength, good magnetic performance and stability, low requirement on equipment and easiness in implementation of application in various fields.
According to the preparation method of the nuclear radiation resistant magnetic particles, the nano magnetic particles are selected from Fe3O4、γ-Fe2O3Or CoFe2O4The nano magnetic particles are prepared by a coprecipitation method.
According to the preparation method of the nuclear radiation resistant magnetic particles, in the step a, the silicon source is selected from at least one of tetraethoxysilane, sodium silicate and polysiloxane, and the weight ratio of the silicon source to the magnetic nanoparticles is (1-6): 1; and/or the alkali is at least one of ammonia water or tetramethoxyammonium hydroxide.
According to the preparation method of the nuclear radiation resistant magnetic particle, the pore-forming agent is selected from at least one of cetyl trimethyl ammonium bromide, octadecyl trimethyl ammonium chloride and hexadecyl trimethyl ammonium chloride, and the weight ratio of the pore-forming agent to the magnetic nano particle is (0.5-2): 1.
According to the preparation method of the nuclear radiation resistant magnetic particles, in the step a, the stirring speed of the sol-gelation reaction is 200-; the solvent comprises an ethanol water solution, wherein the mass ratio of ethanol to water is (1-5) to 1.
According to the preparation method of the nuclear radiation resistant magnetic particles, the method for removing the pore-forming agent in the step b comprises the following steps: dispersing the silicon dioxide-magnetic nano particles in an ethanol solution of ammonium nitrate, and refluxing for 1-4h at 70-90 ℃; or calcining the silicon dioxide-magnetic nano particles at the temperature of 300-400 ℃ for 2-5 h.
According to the preparation method of the modified nuclear radiation resistant magnetic particle, the nuclear radiation resistant magnetic particle or the nuclear radiation resistant magnetic particle prepared by the method is dispersed in a mixed solution of a surfactant and ammonia water, the mixture is heated and stirred, solid particles are separated after cooling, and the solid particles are washed and dried to obtain the modified nuclear radiation resistant magnetic particle, wherein the surfactant is selected from a silane coupling agent or fatty acid with the carbon chain length being more than or equal to 16.
The preparation method of the modified nuclear radiation resistant magnetic particle according to the embodiment of the invention has the following advantages and technical effects: the surface active agent and the ammonia water are used for modifying the nuclear radiation resistant magnetic particles, so that the surface tension of the nuclear radiation resistant magnetic particles is reduced, and the dispersibility and compatibility of the nuclear radiation resistant magnetic particles in the magnetic liquid are improved, thereby improving the nuclear radiation resistance and stability of the magnetic liquid.
The nuclear radiation resistant magnetic liquid comprises a base carrier liquid and the modified nuclear radiation resistant magnetic particles.
The nuclear radiation resistant magnetic liquid provided by the embodiment of the invention has the following advantages and technical effects: 1. the modified nuclear radiation resistant magnetic particles are adopted to improve the dispersion effect of the nuclear radiation resistant magnetic particles in the base carrier liquid, so that the nuclear radiation resistance and the stability of the nuclear radiation resistant magnetic liquid are improved; 2. the mesoporous silica shell layer in the modified nuclear radiation resistant magnetic particles increases the specific surface area of the particles, improves the loading capacity of barium sulfate, increases the contact area of a modifier and the surfaces of the nano magnetic particles, is easy to modify, and is beneficial to improving the dispersion degree and stability of the nuclear radiation resistant magnetic liquid while not affecting the magnetic performance of the magnetic nano particles; 3. the nuclear radiation resistant magnetic liquid provided by the embodiment of the invention has the advantages of simple preparation method, high efficiency, good magnetic saturation strength, good magnetic performance and stability, low requirement on equipment and easiness in implementation of application in various fields.
According to the nuclear radiation resistant magnetic liquid provided by the embodiment of the invention, the particle size of the modified nuclear radiation resistant magnetic particle is 15-30 nm; the base carrier fluid is selected from kerosene, mineral oil, vegetable oil, engine oil, esters or water.
Detailed Description
The following detailed description of embodiments of the invention is intended to be illustrative, and not to be construed as limiting the invention.
A nuclear radiation resistant magnetic particle according to an embodiment of the present invention includes: the surface of the nano magnetic particle is coated by a mesoporous silica layer, wherein the mesoporous silica layer is loaded with barium sulfate.
The nuclear radiation resistant magnetic particles according to the embodiments of the present invention bring advantages and technical effects: 1. in the embodiment of the invention, the mesoporous silica layer on the surface of the nano magnetic particle can load a large amount of barium sulfate, so that the nuclear radiation resistance of the magnetic particle is effectively improved; 2. under the condition that the magnetic performance of the nano magnetic particles is not influenced, the mesoporous silica layer increases the specific surface area of the magnetic particles, increases the contact area of a modifier and the surfaces of the nano magnetic particles, improves the modification capability of the nano magnetic particles, and is favorable for improving the dispersion degree and stability of magnetic liquid prepared subsequently; 3. the nuclear radiation resistant magnetic particles provided by the embodiment of the invention have high nuclear radiation resistance, good magnetic resistance and stability, and are easy to realize application in various fields.
The preparation method of the nuclear radiation resistant magnetic particles comprises the following steps:
a. coating: dispersing the nano magnetic particles, a pore-forming agent and alkali in a solvent, dropwise adding a silicon source, and carrying out sol-gelation reaction to obtain silicon dioxide-magnetic nano particles;
b. pore-forming: removing the pore-forming agent in the silica-magnetic nanoparticles to obtain mesoporous silica-magnetic nanoparticles;
c. loading: and dispersing the mesoporous silica-magnetic nanoparticles in a barium chloride solution for adsorption reaction, then adding a sulfate solution, and separating and washing precipitates to obtain the nuclear radiation resistant magnetic particles.
The preparation method of the nuclear radiation resistant magnetic particles according to the embodiment of the invention has the following advantages and technical effects: 1. according to the preparation method provided by the embodiment of the invention, the mesoporous silicon dioxide layer is coated on the surface of the magnetic nanoparticles by adopting a surface in-situ synthesis method, and then the barium sulfate is loaded on the mesoporous silicon dioxide layer by adopting a coprecipitation method, so that the loading capacity of the barium sulfate is greatly improved due to the high porosity of the mesoporous silicon dioxide layer, and the nuclear radiation resistance of the magnetic particles is effectively improved; 2. the mesoporous silica shell layer is coated on the surface of the magnetic nanoparticles, so that the specific surface area of the particles is increased while the magnetic performance of the magnetic nanoparticles is not influenced, the contact area of a modifier and the surface of the magnetic nanoparticles is increased, the modification capability of the magnetic nanoparticles is improved, and the dispersion degree and the stability of magnetic liquid prepared subsequently are improved; 3. the nuclear radiation resistant magnetic particle provided by the embodiment of the invention has the advantages of simple preparation method, high efficiency, good magnetic saturation strength, good magnetic performance and stability, low requirement on equipment and easiness in implementation of application in various fields.
According to the preparation method of the nuclear radiation resistant magnetic particles, the nano magnetic particles are selected from Fe3O4、γ-Fe2O3Or CoFe2O4The nano magnetic particles are prepared by a coprecipitation method.
Preferably, the method for preparing the nano-magnetic particles comprises the following steps: under the conditions of heating and stirring, dropwise adding concentrated ammonia water into the metal ion solution, carrying out coprecipitation reaction, carrying out magnetic precipitation and washing to obtain nano magnetic particles; wherein, the metal ion solution contains at least one ion of ferric ion, ferrous ion or cobalt ion. Preferably, the method for preparing the nuclear radiation resistant magnetic particle of the embodiment of the invention further comprises the preparation of a nano magnetic particle.
According to the preparation method of the nuclear radiation resistant magnetic particles, in the step a, the silicon source is selected from at least one of tetraethoxysilane, sodium silicate and polysiloxane, and the weight ratio of the silicon source to the magnetic nanoparticles is (1-6): 1; and/or the alkali is at least one of ammonia water or tetramethoxyammonium hydroxide. In the preparation method of the nuclear radiation resistant magnetic particle provided by the embodiment of the invention, the silicon source reagent is preferably added in a manner of dispersing in an ethanol solution and then dropwise adding, so that the silicon source reagent can be fully dispersed in the solution, and the sol-gelation reaction can be promoted by adding an alkaline substance such as ammonia water or tetramethoxyammonium hydroxide. In the embodiment of the invention, the dosage of the silicon source is optimized, if the dosage is too much, the magnetic performance of the magnetic particles can be affected, and if the dosage is too little, the loading capacity of the radiation-proof substance barium sulfate is insufficient, and the effective radiation-proof capability cannot be provided.
According to the preparation method of the nuclear radiation resistant magnetic particles, in the step a, the stirring speed of the sol-gelation reaction is 200-; the solvent ethanol water solution is characterized in that the mass ratio of ethanol to water is (1-5) to 1. According to the preparation method of the nuclear radiation resistant magnetic particles, the stirring speed of the sol-gelation reaction is optimized, so that the silicon source reagent can be fully contacted with the nano magnetic particles in principle, and the surfaces of primary particles are coated with silicon dioxide.
According to the preparation method of the nuclear radiation resistant magnetic particle, the pore-forming agent is selected from at least one of cetyl trimethyl ammonium bromide, octadecyl trimethyl ammonium chloride and cetyl trimethyl ammonium chloride, and the weight ratio of the pore-forming agent to the magnetic nanoparticles is (0.5-2): 1. In the embodiment of the invention, the dosage of the pore-forming agent and the pore-forming agent is optimized, if the dosage of the pore-forming agent is too small, the barium sulfate is not loaded enough, and the radiation protection capability is insufficient; if too much pore former is added, the silica coating will not be successful.
According to the preparation method of the nuclear radiation resistant magnetic particles, the method for removing the pore-forming agent in the step b comprises the following steps: dispersing the silicon dioxide-magnetic nano particles in an ethanol solution of ammonium nitrate, and refluxing for 1-4h at 70-90 ℃; or calcining the silicon dioxide-magnetic nano particles at the temperature of 300-400 ℃ for 2-5 h. The embodiment of the invention optimizes the pore-forming agent removing method according to the properties of the nano magnetic particles, namely Fe3O4The nano magnetic particles are easily oxidized into Fe at high temperature2O3. Preferably, the pore-forming agent is removed by adopting a low-temperature heating reflux mode; gamma-Fe2O3The property is stable, and the pore-forming agent can be removed by adopting a calcining mode.
In step c of the embodiment of the present invention, the precipitate is preferably separated magnetically, which can reduce metal loss.
According to the preparation method of the modified nuclear radiation resistant magnetic particle, the nuclear radiation resistant magnetic particle or the nuclear radiation resistant magnetic particle prepared by the method is dispersed in a mixed solution of a surfactant and ammonia water, the mixture is heated and stirred, solid particles are separated after cooling, and the solid particles are washed and dried to obtain the modified nuclear radiation resistant magnetic particle, wherein the surfactant is selected from a silane coupling agent or fatty acid with the carbon chain length being more than or equal to 16.
The preparation method of the modified nuclear radiation resistant magnetic particle comprises the following steps: the nuclear radiation resistant magnetic particles are modified by the surfactant and the ammonia water, so that the dispersibility and compatibility of the nuclear radiation resistant magnetic particles in the magnetic liquid base carrier liquid are improved, and the nuclear radiation resistant capability and stability of the magnetic liquid are improved.
In the preparation method of the modified nuclear radiation resistant magnetic particle, the modification is preferably carried out at 70-80 ℃ for 1-2 h; preferably, the mass ratio of the surfactant to the ammonia water is 1: (1-2), wherein the concentration of the ammonia water is 5-30 wt%.
Preferably, the silane coupling agent is selected from at least one of methacryloxypropyltriethoxysilane (KH570), Dodecyltrioxysilane (DTEOS) or octadecyltrioxysilane (OTMOS); the fatty acid with the carbon chain length being more than or equal to 16 is selected from at least one of oleic acid, stearic acid or palmitic acid, and is preferably oleic acid.
The nuclear radiation resistant magnetic liquid comprises a base carrier liquid and the modified nuclear radiation resistant magnetic particles.
According to the nuclear radiation resistant magnetic liquid provided by the embodiment of the invention, the modified nuclear radiation resistant magnetic particles are adopted, so that the dispersion effect of the nuclear radiation resistant magnetic particles in the base carrier liquid is improved, and the nuclear radiation resistance and stability of the nuclear radiation resistant magnetic liquid are improved; the mesoporous silica shell layer in the modified nuclear radiation resistant magnetic particles increases the specific surface area of the particles, improves the loading capacity of barium sulfate, increases the contact area of a modifier and the surfaces of the nano magnetic particles, is easy to modify, and is beneficial to improving the dispersion degree and stability of the nuclear radiation resistant magnetic liquid while not affecting the magnetic performance of the magnetic nano particles; the nuclear radiation resistant magnetic liquid provided by the embodiment of the invention has the advantages of simple preparation method, high efficiency, good magnetic saturation strength, good magnetic performance and stability, low requirement on equipment and easiness in implementation of application in various fields.
According to the nuclear radiation resistant magnetic liquid provided by the embodiment of the invention, the particle size of the modified nuclear radiation resistant magnetic particle is 15-30 nm; the base carrier fluid is selected from kerosene, mineral oil, vegetable oil, engine oil, esters or water, preferably dioctyl phthalate. The nuclear radiation resistant magnetic liquid provided by the embodiment of the invention preferably selects the particle size of the modified nuclear radiation resistant magnetic particles so as to ensure that the nuclear radiation resistant magnetic liquid has both magnetic property and nuclear radiation resistance. If the particle size is too large, the particles cannot be stably dispersed in the base carrier liquid, and the magnetic liquid cannot be formed; if the particle diameter is too small, the saturation magnetization is low, and the magnetic properties are deteriorated.
Further, the preparation method of the nuclear radiation resistant magnetic liquid comprises the following steps: the modified nuclear radiation resistant magnetic particles are milled or ultrasonically dispersed in the base carrier fluid.
The present invention will be described in detail with reference to examples.
Example 1
Fe3O4Preparation of nuclear radiation resistant magnetic particles
a. Preparing nano magnetic particles: 11g of FeCl was weighed3·6H2O and 9.7g of FeCl2·4H2Dissolving O in 513mL of deionized water, and stirring for 10min in a water bath at 45 ℃ to ensure that the mixture is uniform; weighing 17g of strong ammonia water, dropwise adding into the mixed salt solution, keeping heating and stirring for 40min, observing that the mixed solution is rapidly changed from yellow to black, carrying out magnetic precipitation, and repeatedly washing with deionized water to obtain black Fe3O4Nano-magnetic particles;
b. coating: 1g of Fe was added to a 500mL three-necked flask3O4Stirring the nano magnetic particles, 70mL of water, 280mL of ethanol and 1g of hexadecyl trimethyl ammonium bromide (CTAB) for 30min under ultrasonic; then adding 10mL ammonia water, 4.5mL tetraethyl orthosilicate (TEOS) dissolved in 20mL ethanol, slowly dropping and stirring for 4h to obtain Fe3O4@SiO2Magnetic particles;
c. pore-forming: fe to be magnetically separated3O4@SiO2After vacuum drying, dispersing the magnetic particles in 200mL of 10mg/L ammonium nitrate ethanol solution, refluxing for 1h at 80 ℃, repeating twice, removing a pore-forming agent CTAB, and obtaining Fe with a mesoporous structure3O4@mSiO2Magnetic particles;
d. loading: 5g of BaCl are weighed2·2H2Dissolving O in 300mL of deionized water to obtain 0.07moL/L barium salt solutionThen the obtained Fe3O4The @ mSiO2 magnetic particles are dispersed in the barium salt solution and stirred for 4 hours; separately, 3g of Na2SO4Dissolving the mixture in 100mL of water to obtain a sodium sulfate solution, and dropwise adding the sodium sulfate solution into a mixed solution of magnetic nanoparticles and barium salt to obtain a BaSO-loaded mixed solution4Fe (b) of3O4@mSiO2Magnetic particles, i.e. Fe3O4Nuclear radiation resistant magnetic particles.
Fe3O4Preparation of nuclear radiation resistant magnetic liquid
(1) Modification: 1.0g of oleic acid, 4g of water and 1.5g of strong ammonia water (the mass concentration is 28%) are weighed and stirred uniformly, and then Fe is added3O4The nuclear radiation resistant magnetic particles are dispersed again to obtain black suspension; heating the suspension in water bath to 80 deg.C, maintaining for 60min, cooling to room temperature, magnetically separating black solid, washing with water until pH is 7, washing with ethanol for three times, and vacuum drying at 60 deg.C for 12 hr to obtain modified Fe3O4Nuclear radiation resistant magnetic particles;
(2) preparing a liquid: modified Fe3O4Grinding nuclear radiation resistant magnetic particles in a mortar, adding dioctyl phthalate, continuously grinding until the mixture is uniform, and performing ultrasonic treatment for 2.5h to obtain Fe3O4A nuclear radiation resistant magnetic fluid.
Example 2
γ-Fe2O3Preparation of nuclear radiation resistant magnetic particles
a. Preparing nano magnetic particles: 11g of FeCl was weighed3·6H2O and 9.7g of FeCl2·4H2Dissolving O in 513mL of deionized water, and stirring for 10min in a water bath at 45 ℃ to ensure that the mixture is uniform; weighing 17g of strong ammonia water, dropwise adding the strong ammonia water into the mixed salt solution, keeping heating and stirring for 40min, and observing that the mixed solution is rapidly changed from yellow to black; magnetic precipitation, repeated washing with deionized water, drying at 100 deg.C for 12 hr to obtain gamma-Fe2O3Nano-magnetic particles;
b. coating: 1g of gamma-Fe is added into a 500mL three-mouth bottle2O3Nano-magnetic particles, 70mL of water, 280mL of ethanol, 1g of hexadecyl trimethyl ammonium bromide(CTAB) stirring for 30min under ultrasound; then 10mL of ammonia water and 4.5mL of Tetraethoxysilane (TEOS) are added and dissolved in 20mL of ethanol, and the mixture is slowly dripped and stirred for 4 hours to prepare the gamma-Fe2O3@SiO2Magnetic particles;
c. pore-forming: gamma-Fe to be magnetically separated2O3@SiO2After vacuum drying, roasting the magnetic particles in a muffle furnace for 3h at 350 ℃, removing a pore-forming agent CTAB, and obtaining the gamma-Fe with a mesoporous structure2O3@mSiO2Magnetic particles;
d. loading: 5g of BaCl are weighed2·2H2Dissolving O in 300mL of deionized water to obtain 0.07moL/L barium salt solution, and then dissolving the obtained gamma-Fe2O3@mSiO2Dispersing the magnetic particles into a barium salt solution, and stirring for 4 hours; separately, 3g of Na2SO4Dissolving the mixture in 100mL of water to obtain a sodium sulfate solution, and dropwise adding the sodium sulfate solution into a mixed solution of magnetic nanoparticles and barium salt to obtain a BaSO-loaded mixed solution4gamma-Fe of2O3@mSiO2Magnetic particles, i.e. gamma-Fe2O3Nuclear radiation resistant magnetic particles.
γ-Fe2O3Preparation of nuclear radiation resistant magnetic liquid
(1) Modification: 1.0g of oleic acid, 4g of water and 1.5g of strong ammonia water (the mass concentration is 28%) are weighed and stirred uniformly, and then gamma-Fe is added2O3The nuclear radiation resistant magnetic particles are dispersed again to obtain black suspension; heating the suspension in water bath to 80 deg.C, maintaining for 60min, cooling to room temperature, magnetically separating black solid, washing with water until pH is 7, washing with ethanol for three times, and vacuum drying at 60 deg.C for 12 hr to obtain modified gamma-Fe2O3Nuclear radiation resistant magnetic particles;
(2) preparing liquid: modified gamma-Fe2O3Grinding the nuclear radiation resistant magnetic particles in a mortar, adding dioctyl phthalate, continuously grinding until the mixture is uniform, and performing ultrasonic treatment for 2.5h to obtain the gamma-Fe2O3A nuclear radiation resistant magnetic fluid.
Example 3
CoFe2O4Preparation of nuclear radiation resistant magnetic particles
a. Preparing nano magnetic particles: 9.7g of CoCl were weighed2·6H2O and 9.7g of FeCl2·4H2Dissolving O in 513mL of deionized water, and stirring for 10min in a water bath at 45 ℃ to ensure that the mixture is uniform; weighing 17g of strong ammonia water, dripping into the mixed salt solution, and keeping heating and stirring for 40 min; after the reaction is finished, magnetically separating the magnetic particles, and repeatedly washing the magnetic particles by deionized water until the conductivity sigma of the eluate is less than or equal to 100 mu s/cm to obtain CoFe2O4Nano-magnetic particles;
b. coating: 1g CoFe was added to a 500mL three-necked flask2O4Stirring the nano magnetic particles, 70mL of water, 280mL of ethanol and 1g of hexadecyl trimethyl ammonium bromide (CTAB) for 30min under ultrasonic; then adding 10mL ammonia water, 4.5mL tetraethyl orthosilicate (TEOS) dissolved in 20mL ethanol, slowly dropping and stirring for 4h to obtain CoFe2O4@SiO2Magnetic particles;
c. pore-forming: magnetic separated CoFe2O4@SiO2After vacuum drying, dispersing the magnetic particles in 200mL of 10mg/L ammonium nitrate ethanol solution, refluxing for 1h at 80 ℃, repeating twice, removing a pore-forming agent CTAB, and obtaining CoFe with a mesoporous structure2O4@mSiO2Magnetic particles; (ii) a
d. Loading: 5g of BaCl are weighed2·2H2O was dissolved in 300mL of deionized water to give a 0.07moL/L barium salt solution, and the resulting CoFe was added2O4@mSiO2Dispersing the magnetic particles into a barium salt solution, and stirring for 4 hours; separately, 3g of Na2SO4Dissolving the mixture in 100mL of water to obtain a sodium sulfate solution, and dropwise adding the sodium sulfate solution into a mixed solution of magnetic nanoparticles and barium salt to obtain a BaSO-loaded mixed solution4CoFe (b) of2O4@mSiO2Magnetic particles, i.e. CoFe2O4Nuclear radiation resistant magnetic particles.
CoFe2O4Preparation of nuclear radiation resistant magnetic liquid
(1) Modification: 1.0g of oleic acid, 4g of water and 1.5g of strong ammonia water (mass concentration is 28%) are weighed and stirred uniformly, and then CoFe is added2O4Nuclear radiation resistant magnetic materialThe particles are dispersed again to obtain black suspension; heating the suspension in water bath to 80 ℃, keeping the temperature for 60min, cooling the suspension to room temperature, magnetically separating black solid, washing with water until the pH value is 7, washing with ethanol for three times, and vacuum-drying at 60 ℃ for 12h to obtain the modified CoFe2O4Nuclear radiation resistant magnetic particles;
(2) preparing liquid: modified CoFe2O4Grinding the nuclear radiation resistant magnetic particles in a mortar, adding dioctyl phthalate, continuously grinding until the mixture is uniform, and performing ultrasonic treatment for 2.5h to obtain CoFe2O4A nuclear radiation resistant magnetic fluid.
Comparative example 1
Same as the preparation method of example 1 except for Fe prepared in step a of example 13O4D, replacing Fe prepared in the step d with nano magnetic particles3O4The nuclear radiation resistant magnetic particles are prepared into magnetic liquid.
Comparative example 2
The same preparation method as that of example 1, except that no pore-forming agent was added in step b, step c was omitted, and no pore-forming treatment was performed on the outer layer of silica.
Comparative example 3
The same preparation method as in example 1 was conducted except that step d was omitted and barium sulfate was not supported in the silica layer.
The nuclear radiation resistant magnetic particles and the magnetic liquid prepared in the above examples and comparative examples are subjected to an irradiation resistance test:
(1) the irradiation dose rate of the sample is 5kGy/h, and the total irradiation dose is 2 multiplied by 103kGy；
(2) Irradiation environment: normal temperature and pressure and aerobic environment.
The test results are shown in Table 1.
TABLE 1
As can be seen from examples 1-3 and comparative example 1, the nuclear radiation resistant magnetic particle silica prepared by the embodiment of the invention has good coating, regular particle size and excellent nuclear radiation resistance; the nuclear radiation resistant magnetic liquid prepared from the nuclear radiation resistant magnetic particles has high nuclear radiation resistant capability, the particles are still uniformly distributed after irradiation, the solution property is stable, the particles are not agglomerated and settled, and the service performance is excellent.
Comparing example 1 with comparative example 2, it can be seen that the mesoporous silica coating formed by adding the pore-forming agent in the example of the present invention not only increases the loading amount of barium sulfate, but also facilitates the modified nuclear radiation resistant magnetic particles to be better dispersed in the base carrier fluid, improves the nuclear radiation resistance of the magnetic fluid, and the magnetic fluid still has better stability after irradiation.
Comparing example 1 with comparative example 3, it can be seen that loading barium sulfate on the magnetic particles can endow the magnetic particles with excellent nuclear radiation resistance, so that the irradiated magnetic particles can still maintain a stable solution state.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A nuclear radiation resistant magnetic particle, comprising: the surface of the nano magnetic particle is coated by a mesoporous silica layer, wherein the mesoporous silica layer is loaded with barium sulfate.
2. A preparation method of nuclear radiation resistant magnetic particles is characterized by comprising the following steps:
a. coating: dispersing the nano magnetic particles, a pore-forming agent and alkali in a solvent, dropwise adding a silicon source, and carrying out sol-gelation reaction to obtain silicon dioxide-magnetic nano particles;
b. pore-forming: removing the pore-forming agent in the silica-magnetic nanoparticles to obtain mesoporous silica-magnetic nanoparticles;
c. loading: and dispersing the mesoporous silica-magnetic nanoparticles in a barium chloride solution for adsorption reaction, then adding a sulfate solution, and separating and washing precipitates to obtain the nuclear radiation resistant magnetic particles.
3. The method according to claim 2, wherein the nanomagnetic particles are selected from Fe3O4、γ-Fe2O3Or CoFe2O4The nano magnetic particles are prepared by a coprecipitation method.
4. The preparation method according to claim 2, wherein in the step a, the silicon source is at least one selected from ethyl orthosilicate, sodium silicate and polysiloxane, and the weight ratio of the silicon source to the magnetic nanoparticles is (1-6): 1; and/or the alkali is at least one of ammonia water or tetramethoxyammonium hydroxide.
5. The preparation method of claim 2, wherein the pore-forming agent is at least one selected from cetyl trimethyl ammonium bromide, octadecyl trimethyl ammonium chloride and hexadecyl trimethyl ammonium chloride, and the weight ratio of the pore-forming agent to the magnetic nanoparticles is (0.5-2): 1.
6. The nuclear radiation resistant magnetic particle as claimed in claim 2, wherein in the step a, the stirring speed of the sol-gel reaction is 200-1000 r/min; the solvent comprises an ethanol water solution, wherein the mass ratio of ethanol to water is (1-5): 1.
7. The nuclear radiation resistant magnetic particles of claim 2, wherein the pore former removal step b comprises: dispersing the silicon dioxide-magnetic nano particles in an ethanol solution of ammonium nitrate, and refluxing for 1-4h at 70-90 ℃; or calcining the silicon dioxide-magnetic nano particles at the temperature of 300-400 ℃ for 2-5 h.
8. A preparation method of modified nuclear radiation resistant magnetic particles is characterized in that the nuclear radiation resistant magnetic particles of claim 1 or the nuclear radiation resistant magnetic particles prepared by the method of any one of claims 2 to 7 are dispersed in a mixed solution of a surfactant and ammonia water, and the modified nuclear radiation resistant magnetic particles are obtained by heating, stirring, cooling, separating solid particles, washing and drying, wherein the surfactant is selected from a silane coupling agent or fatty acid with a carbon chain length of more than or equal to 16.
9. A nuclear radiation resistant magnetic fluid comprising a base carrier fluid and the modified nuclear radiation resistant magnetic particle of claim 8.
10. The nuclear radiation resistant magnetic fluid of claim 9, wherein the modified nuclear radiation resistant magnetic particles have a particle size of 15-30 nm; the base carrier fluid is selected from kerosene, mineral oil, vegetable oil, engine oil, esters or water.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115295269A (en) * | 2022-08-14 | 2022-11-04 | 重庆大学 | Radiation-resistant magnetorheological fluid with high shear yield stress under low magnetic field |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115295269A (en) * | 2022-08-14 | 2022-11-04 | 重庆大学 | Radiation-resistant magnetorheological fluid with high shear yield stress under low magnetic field |
| CN115295269B (en) * | 2022-08-14 | 2024-04-19 | 重庆大学 | Irradiation-resistant magnetorheological fluid with high shear yield stress under low magnetic field |
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