CN-118125803-B - Preparation method of lithium hydride ceramic microspheres

Abstract

The invention discloses a preparation method of lithium hydride ceramic microspheres, and belongs to the field of nuclear reactor application materials. The diameter of the prepared lithium hydride ceramic microsphere is 0.5-3mm, the sphericity is 99.01% at maximum, and the crushing strength is 98.25N. The ceramic microsphere is prepared through compressing airflow through nozzle to blow up the object, and has the principle of providing lifting force to counteract the gravity of the object by means of pressure difference between the upper surface and the lower surface of the object, and the object is in suspended state without need of container or mold support in inert gas atmosphere. The suspended lithium hydride mass is then heated by adjusting the laser intensity to rapidly melt and form molten droplets. The droplets are rapidly spheroidized and rapidly solidified into microspheres under the blowing of argon. The lithium hydride ceramic microsphere provided by the invention has higher lithium density, can be used as a tritium breeder material for producing tritium cladding of a fusion reactor, is important for realizing tritium self-sustaining and stable operation of the fusion reactor, and has great significance for nuclear fusion energy development and utilization.

Inventors

• ZHANG YINGCHUN
• YI BIAO
• SONG SHIHAO

Assignees

• 北京科技大学

Dates

Publication Date

20260512

Application Date

20240119

Claims (7)

1. 1. A preparation method of lithium hydride ceramic microspheres is characterized in that the ceramic microspheres are prepared by a die-free forming process, and objects are blown up by compression of air flow through a nozzle, the principle is that the pressure difference is generated on the upper surface and the lower surface of the objects to provide lifting force to offset the gravity of the objects, the objects are in a suspension state, a container or a die is not required to support the objects under the atmosphere of inert gas, then the suspended lithium hydride blocks are heated and quickly melted by adjusting the intensity of laser to form molten liquid drops, the liquid drops are quickly spheroidized under the blowing of the inert gas and quickly solidified into microspheres; The flow rate of the inert gas is 1.1-1.3L/min, the laser heating temperature is 650-750 ℃, the diameter of the lithium hydride ceramic microsphere is 0.5-5mm, the density is more than 0.80g/cm 3 , the relative density is more than 98.0%, the sphericity is more than 99.0%, and the crushing strength is more than 98.25N.
2. 2. The preparation method of the lithium hydride ceramic microspheres according to claim 1, comprising the following preparation steps: a. selecting crushed lithium hydride blocks in a vacuum glove box under the protection of inert gas atmosphere; b. the equipment adopts an air suspension laser curing instrument, and crushed lithium hydride blocks are added into an air suspension forming area; c. regulating the airflow to stably suspend the lithium hydride block; d. adjusting the laser intensity to heat the lithium hydride block to a surface semi-molten or molten state; e. The surface semi-molten or molten lithium hydride block is rapidly spheroidized under the blowing of inert gas, laser is removed after complete spheroidization, and cold argon is continuously introduced until liquid drops solidify into microspheres; f. And circularly melting the microspheres, and prolonging the suspension time to obtain the lithium hydride ceramic microspheres with higher strength.
3. 3. The method for preparing lithium hydride ceramic microspheres according to claim 2, wherein the particle size of the lithium hydride blocks in step a is 0.5-5mm.
4. 4. The method of claim 2 wherein the support gas of the gas suspension laser curing apparatus in step b is argon, helium or nitrogen.
5. 5. The method of claim 2, wherein the gas flow strength in the step c is 1.1-1.3L/min.
6. 6. The method for preparing lithium hydride ceramic microspheres according to claim 2, wherein the heating temperature in the step d is 650-750 ℃ and the suspension time is 25-35s.
7. 7. The method for preparing lithium hydride ceramic microspheres according to claim 2, wherein the extended suspension time in step f is 40-90s, and the compressive strength of the obtained lithium hydride microspheres is higher than 98.0N.

Description

Preparation method of lithium hydride ceramic microspheres Technical Field The invention belongs to the technical field of nuclear reactor materials, and particularly relates to a preparation method of lithium hydride ceramic microspheres. Background The development of energy has been attracting attention as a support for human development. Fossil energy is still the main body of energy structures in the society today, but the pollution problem of fossil energy makes global environment even more and more, and along with the increasing energy demand, new generation of stable and reliable renewable energy research with environmental friendliness is urgent. Nuclear fusion can be an important future energy problem solution, with deuterium-tritium nuclear fusion becoming the focus of research. Establishing a highly efficient deuterium-tritium fuel system is an indispensable condition for achieving nuclear fusion reaction teams. Deuterium required for nuclear fusion is almost everywhere visible in nature, however, the natural content of tritium, another important raw material, is extremely low, and therefore, in order to meet the requirements of nuclear fusion, artificial production of tritium is required. Tritium is generated by nuclear reaction between lithium and neutrons and is re-injected into the reactor core to sustain the nuclear fusion reaction. The magnetic confinement nuclear fusion reactor has more use requirements on tritium breeder, needs to have (1) smaller neutron cross section, (2) excellent mechanical property, can not be crushed when being used for a long time in ton level, (3) higher lithium density content and higher tritium breeder capability, and (4) better irradiation stability, and avoids structural change under high-temperature and high-irradiation environment. At present, materials such as LiO 2,LiTiO3,LiSiO4 and the like are used as tritium breeder, and the materials are paid attention to because of good properties, but the materials have the defect that the density content of lithium atoms is relatively low. Lithium hydride, a potential tritium breeder, has a high lithium density content and a relatively high melting point, which makes it a unique advantage for use as a tritium breeder in fusion stacks. However, research on lithium hydride in ceramic microspheres is relatively few at home and abroad. Disclosure of Invention The invention aims to provide a novel gas-shielded non-mold forming method for preparing lithium hydride ceramic microspheres, which fills the blank of the preparation technology in the aspect of lithium hydride microspheres for fusion reactor cladding tritium breeder. In order to achieve the above purpose, the technical scheme of the invention is as follows: the method is a die-free technology, and can effectively avoid the defects of heterogeneous nucleation, pollution, internal stress and the like caused by contact with the die wall, and the prepared lithium hydride ceramic microsphere has high compactness, high solidification speed and high sphericity. A preparation method of lithium hydride ceramic microspheres is characterized in that the ceramic microspheres are prepared through a die-free forming process, objects are blown up by compression of air flow through a nozzle, the principle is that pressure difference is generated on the upper surface and the lower surface of the objects to provide lifting force to offset the gravity of the objects, the objects are in a suspension state, a container or a die is not needed to support the objects under the atmosphere of inert gas, then suspended lithium hydride blocks are heated to be quickly melted by adjusting the laser intensity to form molten liquid drops, the liquid drops are quickly spheroidized under the blowing of the inert gas, and the prepared lithium hydride ceramic microspheres are pure lithium hydride and have high purity, high lithium density and high sphere strength. Further, when the flow rate of the inert gas or nitrogen gas is 1.1-1.3L/min and the laser heating temperature is 650-750 ℃, the diameter of the lithium hydride ceramic microsphere is 0.5-5mm, the density is >0.80g/cm 3, the relative density is >98.0%, the sphericity is higher than 99.0%, and the crushing strength is >98.25N. Further, the preparation method of the lithium hydride ceramic microsphere comprises the following preparation steps: a. Selecting crushed lithium hydride blocks in a vacuum glove box under the protection of inert gas or nitrogen atmosphere; b. the equipment adopts an air suspension laser curing instrument, and crushed lithium hydride blocks are added into an air suspension forming area; c. regulating the airflow to stably suspend the lithium hydride block; d. adjusting the laser intensity to heat the lithium hydride block to a surface semi-molten or molten state; e. The surface semi-molten or molten lithium hydride block is rapidly spheroidized under the blowing of inert gas or nitrogen, laser is removed after compl