Composite neutron absorbing material and preparation method thereof
A composite neutron absorbing material using basalt, polyethylene, and boron carbide with platinum catalyst processing enhances flexibility and temperature resistance, effectively addressing material degradation in high-energy radiation environments.
Patent Information
- Application Number
- CN202411267456.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2024-12-10
Smart Images
Figure BDA0005037564590000081
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of neutron shielding materials, and in particular relates to a composite neutron absorbing material and a preparation method thereof. Background Art
[0002] With the rapid development of nuclear power, nuclear-powered ships, irradiation processing, non-destructive testing, radiotherapy and other industries, high-energy radiation rays have been widely used in many fields such as industry, medical treatment, scientific research, etc. The main radiation protection targets are X-rays, Y-rays and neutrons. Neutrons are one of the basic particles that make up the nucleus of atoms. They are not charged themselves, but because of their high speed, they can ionize matter and produce radioactive radiation. They are widely used in national defense, scientific research, radiotherapy and detection. Neutrons are indispensable in the development of nuclear power using nuclear fission, providing humans with a large amount of clean energy. However, a large number of secondary particles produced by neutron ionization will interact with tissue cells, causing great harm to human health. At the same time, neutron irradiation can cause point defects and dislocations inside the material, causing the material performance to degrade. Therefore, the shielding and protection of nuclear neutrons and gamma rays has become one of the key factors in the development of a new generation of nuclear energy.
[0003] At present, polymer composite materials are often used to shield neutrons. Compared with traditional metals and concrete, polymer composite materials have the characteristics of low density, good attenuation curve, easy use, low cost, good processing performance, etc., which can meet the needs of radiation occasions with different energy levels. The existing new composite materials for shielding high-energy radiation rays mostly contain silicon carbide components, which are used as neutron absorbers, but the flexibility and high and low temperature resistance of the composite materials are poor, and they are prone to decomposition in high temperature environments for a long time. Therefore, how to provide a neutron shielding material with good flexibility and good high and low temperature resistance and its preparation method is a technical problem to be solved by those skilled in the art. Summary of the invention
[0004] In view of the problems of poor flexibility and high and low temperature resistance of current neutron absorbing materials, the present invention aims to provide a composite neutron absorbing material and a preparation method thereof.
[0005] The purpose of the present invention is to provide a composite neutron absorbing material, which comprises the following components by mass: 50-70 parts of basalt, 30-50 parts of polyethylene, 1-2 parts of platinum catalyst and 20-40 parts of boron carbide.
[0006] Furthermore, the polyethylene is a combination of high-density polyethylene and low-density polyethylene in a mass ratio of 3 to 8:1; the density of the high-density polyethylene is 0.910 to 0.925 g / cm3, and the density of the low-density polyethylene is 0.830 to 0.900 g / cm3.
[0007] Furthermore, the particle size of the basalt is 80-100 μm; the particle size of the boron carbide is 50-100 μm.
[0008] Furthermore, the mass concentration of Pt in the platinum catalyst is 1000-3000 ppm.
[0009] A method for preparing a composite neutron absorbing material comprises the following steps:
[0010] (1) taking each component according to the above mass fraction, first mixing basalt, boron carbide, polyethylene and platinum catalyst to obtain a mixed material, adding anhydrous ethanol to ball mill to obtain a ball mill material; adding water to the ball mill material, ultrasonic treatment, filtering and drying, hot mixing and internal kneading, discharging the material, and standing to room temperature to obtain a material to be treated;
[0011] (2) The material to be treated is subjected to hot pressing operation, cooled, depressurized and demolded to obtain a composite neutron absorbing material.
[0012] Furthermore, in step (1), the amount of anhydrous ethanol added is 40-60% of the mass of the mixture.
[0013] Furthermore, the ultrasonic treatment in step (1) is performed at a power of 300 to 500 W for 15 to 30 minutes.
[0014] Furthermore, the hot mixing and kneading conditions in step (1) are: hot mixing and kneading at 150-250° C. for 30-60 min.
[0015] Furthermore, the hot pressing conditions in step (2) are: firstly, the temperature is increased from 100°C to 300°C at a rate of 3-7°C / min while maintaining the pressure at 15-20MPa, and then the temperature is increased to 450°C at a rate of 5-10°C / min and the pressure is maintained at 30-70MPa, and the temperature and pressure are maintained for 1-3h.
[0016] Compared with the prior art, the advantages of the present invention are:
[0017] The present invention adopts basalt, polyethylene and boron carbide as main raw materials, wherein the basalt has stable performance, high temperature resistance, low temperature resistance, strong plasticity, is suitable for processing, and optimizes the main body of the construction material; polyethylene adopts a combination of high density and low density to improve the overall flexibility. Tests have shown that the addition of low-density polyethylene significantly improves the flexibility. The polyethylene not only provides good mechanical strength and processing performance for the material, but also makes the entire material lighter, easier to install and use; the overall material has an extremely high neutron absorption cross-section, can undergo nuclear reactions with neutrons, and convert them into stable nuclides, and has good applicability. The composite neutron absorption material prepared by the present invention contains boron and polyethylene components and has broad application prospects in the field of nuclear energy. In a nuclear reactor, the boron-containing polyethylene sheet can be used as a neutron shielding material to effectively absorb and reduce the radiation intensity of neutrons and protect the safe operation of the reactor; in the field of nuclear weapons, the boron-containing polyethylene sheet can be used as a neutron moderator and a reflective layer material to improve the lethality and deterrence of the weapon. DETAILED DESCRIPTION
[0018] The following provides a specific implementation of a composite neutron absorbing material and a preparation method thereof of the present invention. It is necessary to point out that the following examples are only used to illustrate the present invention in more detail, rather than to narrow the scope of protection of the present invention. After reading the present invention, improvements and adjustments made by professionals in this technical field without departing from the concept of the present invention are within the scope of protection claimed by the present invention.
[0019] A composite neutron absorbing material, comprising the following components by mass:
[0020] 50-70 parts of basalt, 30-50 parts of polyethylene, 1-2 parts of platinum catalyst, and 20-40 parts of boron carbide.
[0021] Among them, the particle size of basalt is 80 to 100 μm.
[0022] The polyethylene is a combination of high-density polyethylene and low-density polyethylene in a mass ratio of 3 to 8:1; the density of the high-density polyethylene is 0.910 to 0.925 g / cm3, and the density of the low-density polyethylene is 0.830 to 0.900 g / cm3.
[0023] The mass concentration of Pt in the platinum catalyst is 1000-3000ppm.
[0024] The particle size of the boron carbide is 50 to 100 μm.
[0025] A method for preparing a composite neutron absorbing material comprises the following steps:
[0026] (1) taking each component according to the above mass fraction, first mixing basalt, boron carbide, polyethylene and platinum catalyst to obtain a mixed material, adding 40-60% of anhydrous ethanol by mass of the mixed material and ball milling for 1-2 hours to obtain a ball mill; adding 1-2 times of water by mass of the ball mill to the ball mill, ultrasonically treating the ball mill at a power of 300-500 W for 15-30 minutes, filtering and drying, putting the ball mill into an internal mixer and hot mixing and kneading at 150-250° C. for 30-60 minutes, discharging the material, and letting it stand to room temperature to obtain a material to be treated;
[0027] (2) placing the material to be treated into a hot press mold, and performing hot pressing operation using a hot press. The hot pressing conditions are: first, heating from 100°C to 300°C at a rate of 3-7°C / min, while maintaining a pressure of 15-20MPa, then heating to 450°C at a rate of 5-10°C / min, and maintaining a pressure of 30-70MPa for 1-3h; then, cooling, depressurizing, and demolding to obtain a composite neutron absorbing material.
[0028] Example 1
[0029] A composite neutron absorbing material, comprising the following components by mass:
[0030] 50 parts of basalt, 30 parts of polyethylene, 1 part of platinum catalyst, 20 parts of boron carbide.
[0031] Among them, the particle size of basalt is 80μm.
[0032] The polyethylene is a combination of high-density polyethylene and low-density polyethylene in a mass ratio of 5:1; the density of the high-density polyethylene is 0.910-0.925 g / cm3, and the density of the low-density polyethylene is 0.830-0.900 g / cm3.
[0033] The mass concentration of Pt in the platinum catalyst is 1000-3000ppm.
[0034] The particle size of boron carbide is 60 μm.
[0035] A method for preparing a composite neutron absorbing material comprises the following steps:
[0036] (1) taking each component according to the above mass fraction, first mixing basalt, boron carbide, polyethylene and platinum catalyst to obtain a mixed material, adding 40% of the mass of anhydrous ethanol to ball mill for 1 hour to obtain a ball mill; adding 1 times the mass of water to the ball mill, ultrasonically treating the ball mill at a power of 400 W for 30 minutes, filtering and drying, putting it into an internal mixer and hot mixing and internal kneading at 200° C. for 50 minutes, discharging the material, and letting it stand to room temperature to obtain a material to be treated;
[0037] (2) placing the material to be treated into a hot press mold, and performing hot pressing operation using a hot press. The hot pressing conditions are: first, heating from 100°C to 300°C at a rate of 5°C / min while maintaining a pressure of 20MPa, then heating to 450°C at a rate of 6°C / min and maintaining a pressure of 50MPa for 3h; then cooling, depressurizing and demolding to obtain a composite neutron absorbing material.
[0038] Example 2
[0039] A composite neutron absorbing material, comprising the following components by mass:
[0040] 60 parts of basalt, 40 parts of polyethylene, 1 part of platinum catalyst, 30 parts of boron carbide.
[0041] Among them, the particle size of basalt is 90μm.
[0042] The polyethylene is a combination of high-density polyethylene and low-density polyethylene in a mass ratio of 5:1; the density of the high-density polyethylene is 0.910-0.925 g / cm3, and the density of the low-density polyethylene is 0.830-0.900 g / cm3.
[0043] The mass concentration of Pt in the platinum catalyst is 2000 ppm.
[0044] The particle size of boron carbide is 70 μm.
[0045] A method for preparing a composite neutron absorbing material comprises the following steps:
[0046] (1) Taking each component according to the above mass fraction, first mix basalt, boron carbide, polyethylene and platinum catalyst to obtain a mixed material, add 50% of the mass of anhydrous ethanol to ball mill for 1 hour to obtain a ball mill; after adding 1 times the mass of water to the ball mill, ultrasonically treat the ball mill at a power of 400 W for 30 minutes, then filter and dry, put it into an internal mixer and heat mix it at 200° C. for 50 minutes, discharge it, and let it stand to room temperature to obtain a material to be treated;
[0047] (2) placing the material to be treated into a hot press mold, and performing hot pressing operation using a hot press. The hot pressing conditions are: first, heating from 100°C to 300°C at a rate of 5°C / min while maintaining a pressure of 15MPa, then heating to 450°C at a rate of 7°C / min and maintaining a pressure of 50MPa for 2h; then cooling, depressurizing and demolding to obtain a composite neutron absorbing material.
[0048] Example 3
[0049] A composite neutron absorbing material, comprising the following components by mass:
[0050] 70 parts of basalt, 50 parts of polyethylene, 2 parts of platinum catalyst, 40 parts of boron carbide.
[0051] Among them, the particle size of basalt is 100μm.
[0052] The polyethylene is a combination of high-density polyethylene and low-density polyethylene in a mass ratio of 8:1; the density of the high-density polyethylene is 0.910-0.925 g / cm, and the density of the low-density polyethylene is 0.830-0.900 g / cm.
[0053] The mass concentration of Pt in the platinum catalyst is 3000 ppm.
[0054] The particle size of boron carbide is 100 μm.
[0055] A method for preparing a composite neutron absorbing material comprises the following steps:
[0056] (1) taking each component according to the above mass fraction, first mixing basalt, boron carbide, polyethylene and platinum catalyst to obtain a mixed material, adding 60% of the mass of anhydrous ethanol to ball mill for 2 hours to obtain a ball mill; adding water twice the mass of the ball mill to the ball mill, ultrasonically treating the ball mill at a power of 500 W for 30 minutes, filtering and drying, putting it into an internal mixer and hot mixing and internal kneading at 250° C. for 60 minutes, discharging the material, and letting it stand to room temperature to obtain a material to be treated;
[0057] (2) placing the material to be treated into a hot press mold, and performing hot pressing operation using a hot press. The hot pressing conditions are: first, heating from 100°C to 300°C at a rate of 5°C / min while maintaining a pressure of 20MPa, then heating to 450°C at a rate of 10°C / min and maintaining a pressure of 70MPa for 3 hours; then cooling, releasing the pressure and demolding to obtain a composite neutron absorbing material.
[0058] Comparative Example 1: It is basically the same as Example 2, except that basalt is missing.
[0059] Comparative Example 2: It is basically the same as Example 2, except that the low-density polyethylene in the polyethylene component is missing.
[0060] The flexibility, high and low temperature resistance, and neutron shielding performance of Examples 1 to 2 and Comparative Examples 1 to 2 were tested. The specific test results are shown in Table 1, wherein the high temperature resistance test was conducted in accordance with GBT 2423.2-2008, and the low temperature resistance test was conducted in accordance with GBT 2423.1-2008.
[0061] Table 1. Performance test results
[0062]
[0063] From the above test, it can be seen that the products obtained in Examples 1 to 3 have good performance effects. Comparative Example 1 lacks the main component basalt, resulting in a significant decrease in elongation at break, low temperature resistance, and high temperature resistance; Comparative Example 2 lacks the low-density polyethylene in the polyethylene component, resulting in a significant decrease in elongation at break and a decrease in flexibility.
[0064] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; therefore, although this specification has described the present invention in detail with reference to the above embodiments, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.
Claims
1. A composite neutron absorbing material, characterized in that: The invention comprises the following components by weight: 50 to 70 parts of basalt, 30 to 50 parts of polyethylene, 1 to 2 parts of platinum catalyst and 20 to 40 parts of boron carbide.
2. The composite neutron absorbing material according to claim 1, characterized in that: The polyethylene is a combination of high-density polyethylene and low-density polyethylene in a mass ratio of 3 to 8:1; the density of the high-density polyethylene is 0.910 to 0.925 g / cm3, and the density of the low-density polyethylene is 0.830 to 0.900 g / cm3.
3. The composite neutron absorbing material according to claim 1, characterized in that: The particle size of the basalt is 80-100 μm, and the particle size of the boron carbide is 50-100 μm.
4. The composite neutron absorbing material according to claim 1, characterized in that: The mass concentration of Pt in the platinum catalyst is 1000-3000 ppm.
5. A method for preparing the composite neutron absorbing material according to claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) taking each component according to the above mass fraction, first mixing basalt, boron carbide, polyethylene and platinum catalyst to obtain a mixed material, adding anhydrous ethanol to ball mill to obtain a ball mill material; adding water to the ball mill material, ultrasonic treatment, filtering and drying, hot mixing and internal kneading, discharging the material, and standing to room temperature to obtain a material to be treated; (2) The material to be treated is subjected to hot pressing operation, cooled, depressurized and demolded to obtain a composite neutron absorbing material.
6. The method for preparing a composite neutron absorbing material according to claim 5, characterized in that: In the step (1), the amount of anhydrous ethanol added is 40-60% of the mass of the mixed material.
7. The method for preparing a composite neutron absorbing material according to claim 5, characterized in that: The conditions for the ultrasonic treatment in step (1) are: ultrasonic treatment at a power of 300 to 500 W for 15 to 30 minutes.
8. The method for preparing a composite neutron absorbing material according to claim 5, characterized in that: The hot mixing and kneading conditions in the step (1) are: hot mixing and kneading at 150-250° C. for 30-60 min.
9. The method for preparing a composite neutron absorbing material according to claim 5, characterized in that: The hot pressing conditions in step (2) are: first, heating from 100°C to 300°C at a rate of 3-7°C / min while maintaining a pressure of 15-20MPa, then heating to 450°C at a rate of 5-10°C / min and maintaining a pressure of 30-70MPa for 1-3h.