A method for preparing lithium hydride ceramic microspheres

Abstract

The application discloses a preparation method of lithium hydride ceramic microspheres and belongs to the field of nuclear reactor application materials. The prepared lithium hydride ceramic microspheres have a diameter of 0.5-3 mm, a maximum sphericity of 99.01%, and a compressive strength of 98.25 N. The preparation method of the ceramic microspheres is to use airflow to compress and blow an object through a nozzle, the principle of which is to generate a pressure difference between the upper and lower surfaces of the object to provide a lifting force to offset the gravity of the object, so that the object is in a suspended state and is supported without a container or a mold in an inert gas atmosphere. Subsequently, the suspended lithium hydride block is heated by adjusting the laser intensity to rapidly melt the lithium hydride block, so that molten droplets are formed. The droplets are rapidly spheroidized under the blowing of argon gas and rapidly solidified into microspheres. The lithium hydride ceramic microspheres provided by the application have a high lithium density and can be used as tritium breeder material for a fusion reactor tritium production blanket. The lithium hydride ceramic microspheres are crucial for the realization of tritium self-sustaining and stable operation of the fusion reactor, and the application has great significance for the development and utilization of nuclear fusion energy.

Description

Technical Field

[0001] This invention belongs to the field of nuclear reactor materials technology, specifically relating to a method for preparing lithium hydride ceramic microspheres. Background Technology

[0002] Energy development, as a pillar of human progress, has always attracted much attention. In today's society, fossil fuels remain the mainstay of the energy structure, but the pollution caused by fossil fuels is leading to a deteriorating global environment. With the continuous increase in energy demand, research into a new generation of stable, reliable, and environmentally friendly renewable energy sources is urgently needed. Nuclear fusion energy, as an important solution to future energy problems, has made deuterium-tritium nuclear fusion a key research focus. Establishing an efficient deuterium-tritium fuel system is an indispensable condition for realizing nuclear fusion reactions. Deuterium, required for nuclear fusion, is almost ubiquitous in nature; however, the natural abundance of tritium, another important raw material, is extremely low. Therefore, to meet the needs of nuclear fusion, tritium needs to be produced artificially.

[0003] Tritium is produced through nuclear reactions between lithium and neutrons, and then reinjected into the reactor core to sustain the nuclear fusion reaction. Magnetic confinement fusion reactors have several requirements for the tritium breeder, including (1) a small neutron cross-section; (2) excellent mechanical properties, so that it will not be crushed during long-term use at the ton level; (3) a high lithium density content, which enables it to breed tritium; and (4) good radiation stability, which prevents structural changes under high temperature and high radiation conditions. Currently, there is considerable research on the use of materials such as LiO2, LiTiO3, and LiSiO4 as tritium breeders, and these materials have attracted much attention due to their excellent performance. However, these materials all have a drawback: the density of lithium atoms is relatively low.

[0004] Lithium hydride, as a potential tritium breeder, has a high lithium density and a high melting point, giving it a unique advantage in fusion reactors. However, research on lithium hydride in ceramic microspheres is relatively limited both domestically and internationally. Summary of the Invention

[0005] The purpose of this invention is to provide a novel gas-protected moldless molding method for preparing lithium hydride ceramic microspheres, filling the technological gap in the preparation of lithium hydride microspheres for tritium breeder in fusion reactor blankets.

[0006] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0007] Lithium hydride ceramic microspheres were prepared using a moldless molding method. This method is a moldless technology that can effectively avoid the disadvantages of heterogeneous nucleation, contamination, and internal stress caused by contact with the mold wall. The prepared lithium hydride ceramic microspheres have high density, fast solidification speed, and high sphericity.

[0008] A method for preparing lithium hydride ceramic microspheres, characterized in that the ceramic microspheres are prepared by a moldless molding process, utilizing airflow compressed through a nozzle to lift an object. The principle is to create a pressure difference between the upper and lower surfaces of the object to provide lift and counteract the object's gravity, thus suspending the object in a suspended state. No container or mold support is required under an inert gas atmosphere. Subsequently, the suspended lithium hydride block is heated by adjusting the laser intensity to rapidly melt it, forming molten droplets. The droplets are rapidly sphericalized under the blowing of the inert gas and quickly solidify into microspheres. The prepared lithium hydride ceramic microspheres are pure lithium hydride with high purity, high lithium density, and high spherical strength.

[0009] Furthermore, when the inert gas or nitrogen gas flow rate is 1.1-1.3 L / min and the laser heating temperature is 650℃-750℃, the diameter of the lithium hydride ceramic microspheres is 0.5-5 mm and the density is >0.80 g / cm³. 3 Relative density > 98.0%, sphericity > 99.0%, crushing strength > 98.25 N.

[0010] Furthermore, the preparation method for the lithium hydride ceramic microspheres described above includes the following steps:

[0011] a. Select the broken lithium hydride blocks inside a vacuum glove box under an inert gas or nitrogen atmosphere.

[0012] b. The equipment uses an air suspension laser curing device to add the crushed lithium hydride blocks into the air suspension forming area;

[0013] c. Adjust the airflow to stably suspend the lithium hydride block;

[0014] d. Adjust the laser intensity to heat the lithium hydride block until the surface is in a semi-molten or molten state;

[0015] e. The semi-molten or molten lithium hydride bulk material is rapidly spheroidized under the blowing of inert gas or nitrogen. After complete spheroidization, the laser is removed, and cold argon gas is continuously introduced until the droplets solidify into microspheres. f. The microspheres are cyclically melted and the suspension time is extended to obtain lithium hydride ceramic microspheres with higher strength.

[0016] Furthermore, the particle size of the lithium hydride bulk material described in step a is 0.5-5 mm.

[0017] Furthermore, the supporting gas for the air suspension laser curing instrument described in step b is argon, helium, or nitrogen.

[0018] Furthermore, the airflow intensity mentioned in step c is 1.1-1.3 L / min.

[0019] Furthermore, the heating temperature in step d is 650-750℃, and the suspension time is 25-35s.

[0020] Furthermore, the extended suspension time mentioned in step f refers to a suspension time of 40-90 seconds, at which point the compressive strength of the lithium hydride microspheres obtained is higher than 98.0 N.

[0021] The key point of this invention is:

[0022] This invention prepares lithium hydride ceramic microspheres using a moldless molding method. XRD analysis of the prepared lithium hydride microspheres using the described steps shows that the main component is lithium hydride. The microsphere particle size is approximately 0.5-5 mm. The sphericity of the prepared lithium hydride ceramic microspheres is higher than 99.0%.

[0023] This invention observes the mechanical properties of lithium hydride ceramic microspheres after different suspension times and concludes that the maximum crushing strength of lithium hydride microspheres after suspension for 40 seconds is >98.25N.

[0024] The advantages of this invention are that the provided lithium hydride ceramic microspheres have a high lithium density, a diameter of 0.5-3 mm, a maximum sphericity of 99.01%, and a crushing strength of 98.25 N. These microspheres can be used as tritium breeder materials in the tritium blanket of fusion reactors, which is crucial for achieving tritium self-sufficiency and stable operation. This invention has significant implications for the development and utilization of nuclear fusion energy. Attached Figure Description

[0025] Figure 1 The image shows the XRD pattern of lithium hydride ceramic microspheres.

[0026] Figure 2 The relationship between sphericity and suspension time of lithium hydride ceramic microspheres.

[0027] Figure 3 The relationship between sphericity and suspension time of lithium hydride ceramic microspheres after multiple cyclic melting.

[0028] Figure 4 The relationship between the crush resistance strength and suspension time of lithium hydride ceramic microspheres after multiple cyclic melting is shown.

[0029] Figure 5 The surface and cross-sectional morphology of lithium hydride ceramic microspheres. Detailed Implementation

[0030] Example 1: Preparation of lithium hydride ceramic microspheres using the method of the present invention.

[0031] The specific operating steps are as follows:

[0032] a. Select lithium hydride blocks with a particle size of about 2mm after crushing in a vacuum glove box under argon atmosphere protection.

[0033] b. Add the crushed lithium hydride blocks into the air suspension forming area;

[0034] c. Adjust the argon gas flow rate to 1.1 L / min to stably suspend the lithium hydride block;

[0035] d. Adjust the laser intensity to heat the lithium hydride block to above 650°C until the surface is slightly melted or molten, so that its suspension time reaches 30s.

[0036] e. The lithium hydride block in a slightly molten or melted state is rapidly spheroidized under argon blowing. After spheroidization is complete, the laser is removed, and cold argon is continuously introduced until the surface solidifies into microspheres.

[0037] f. The microspheres are cyclically melted and the suspension time is extended to obtain lithium hydride ceramic microspheres with higher strength.

[0038] Examples 2-37

[0039] Except for the gas flow rate, the processes in Examples 2-10 are completely identical to those in Example 1. For details of the relevant process parameters and physical properties of the specific examples, please refer to Table 1.

[0040] Example Gas flow rate Can it float stably? 2 1.0 cannot 3 1.1 able 4 1.2 able 5 1.3 able 6 1.4 cannot 7 1.5 cannot 8 1.6 cannot 9 1.7 cannot 10 1.8 cannot

[0041] Except for the suspension time process parameter, the processes of Examples 12-19 are completely the same as those of Example 1. For details of the relevant process parameters and physical properties of the specific examples, please refer to Table 2.

[0042] Example Suspension time sphericity 11 10 86.57％ 12 20 93.11％ 13 30 96.46％ 14 40 95.17％ 15 50 94.69％ 16 60 93.68％ 17 70 94.76％ 18 80 93.12％ 19 90 94.38％

[0043] Examples 20-28 are multiple-cycle molten microspheres. Except for the suspension time process parameter, the process is completely the same as that of Example 1. For details of the relevant process parameters and physical properties of the specific examples, please refer to Table 3.

[0044] Example Suspension time sphericity 20 10 86.57％ 21 20 94.26％ 22 30 99.01％ 23 40 99.00％ 24 50 99.01％ 25 60 99.02％ 26 70 99.00％ 27 80 98.99％ 28 90 98.89％

[0045] Examples 29-37 are multiple-cycle molten microspheres. Except for the suspension time process parameter, the process is completely the same as that of Example 1. For details of the relevant process parameters and physical properties of the specific examples, please refer to Table 4.

[0046] Example Suspension time Crushing strength 29 10 84.10 MPa 30 20 91.21MPa 31 30 95.57MPa 32 40 98.25MPa 33 50 98.25MPa 34 60 98.23MPa 35 70 98.26MPa 36 80 98.24MPa 37 90 98.25MPa

Claims

1. A method for preparing lithium hydride ceramic microspheres, characterized in that, The ceramic microspheres are prepared using a moldless molding process. An object is lifted by compressed airflow through a nozzle, creating a pressure difference between the upper and lower surfaces to provide lift and counteract gravity, thus suspending the object in an inert gas atmosphere without the need for containers or molds. Subsequently, the suspended lithium hydride mass is rapidly melted by adjusting the laser intensity, forming molten droplets. These droplets are then rapidly sphericalized and solidified into microspheres under the influence of the inert gas. The microspheres are then circulated and melted, with the suspension time extended to obtain lithium hydride ceramic microspheres with higher strength. The prepared lithium hydride ceramic microspheres are made of pure lithium hydride, exhibiting high purity, high lithium density, and high spherical strength. The inert gas flow rate is 1.1-1.3 L / min, the laser heating temperature is 650℃-750℃, and the diameter of the lithium hydride ceramic microspheres is 0.5-5 mm with a density > 0.80 g / cm³. 3 Relative density > 98.0%, sphericity > 99.0%, crushing strength > 98.25 N.

2. The preparation method of lithium hydride ceramic microspheres according to claim 1, wherein the preparation steps are as follows: a. Select the broken lithium hydride blocks inside a vacuum glove box under an inert gas atmosphere; b. The equipment uses an air suspension laser curing device to add the crushed lithium hydride blocks into the air suspension forming area; c. Adjust the airflow to stably suspend the lithium hydride block; d. Adjust the laser intensity to heat the lithium hydride block until the surface is in a semi-molten or molten state; e. The semi-molten or molten lithium hydride block is rapidly spheroidized under the blowing of inert gas. After the spheroidization is complete, the laser is removed, and cold argon gas is continuously introduced until the droplets solidify into microspheres. f. The microspheres are cyclically melted and the suspension time is extended to obtain lithium hydride ceramic microspheres with higher strength.

3. The method for preparing lithium hydride ceramic microspheres according to claim 2, characterized in that: The particle size of the lithium hydride bulk material mentioned in step a is 0.5-5 mm.

4. The method for preparing lithium hydride ceramic microspheres according to claim 2, characterized in that: The supporting gas for the air suspension laser curing instrument described in step b is argon, helium, or nitrogen.

5. The method for preparing lithium hydride ceramic microspheres according to claim 2, characterized in that: The airflow intensity mentioned in step c is 1.1-1.3 L / min.

6. The method for preparing lithium hydride ceramic microspheres according to claim 2, characterized in that: The heating temperature in step d is 650-750℃, and the suspension time is 25-35s.

7. The method for preparing lithium hydride ceramic microspheres according to claim 2, characterized in that: The extended suspension time mentioned in step f refers to a suspension time of 40-90 seconds, at which point the compressive strength of the lithium hydride microspheres obtained is higher than 98.0 N.

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