System for vacuum heating reduction of alkali metal elements

Abstract

The application relates to the technical field of atomic gas chamber manufacturing, in particular to a vacuum heating reduction preparation system of alkali metal elements. The vacuum heating reduction preparation system of alkali metal elements comprises a reaction container, a glass vacuum device, a first heating piece, a second heating piece and a temperature control device. The glass vacuum device comprises a glass diffusion pump and a mechanical pump, one side of the glass diffusion pump is connected with the reaction container, and the other side is connected with the mechanical pump. The first heating piece is used for heating the mixed materials in the reaction container, and the second heating piece is used for baking and degassing the reaction container. The temperature control device is electrically connected with the first heating piece and the second heating piece. The glass diffusion pump is used as a main pump, which is beneficial to removing the gas in the system before the reaction and the gas generated during the reduction reaction, improves the ultimate vacuum degree of the system, and obviously enhances the alkali metal vapor corrosion resistance of the glass vacuum device compared with the metal vacuum device. After long-term use, the vacuum degree of the system is reduced little, and the high-purity alkali metal elements meeting the vacuum filling of the atomic clock atomic gas chamber can be stably prepared.

Description

Technical Field

[0001] This application relates to the field of atomic gas chamber manufacturing technology, and in particular to a vacuum heating reduction preparation system for alkali metal elements. Background Technology

[0002] Alkali metals (rubidium or cesium) are the main working materials in the atomic gas chambers of quantum frequency standards and quantum sensors, and need to be encapsulated in a glass gas chamber with a specific buffer gas. Because quantum devices have high technical requirements, and alkali metals are physically and chemically highly reactive, filling and precisely controlling the mass of the alkali metal and the pressure of the buffer gas in a vacuum environment has become one of the main process and technical challenges in the preparation of atomic gas chambers.

[0003] Alkali metals, as widely used industrial products, are typically stored and transported in chloride form. During use, thermal vacuum reduction equipment is required. Under ultra-high vacuum conditions, the chlorides are heated to 500–700°C, reduced and purified, and then dispensed into glass ampoules for later use.

[0004] Existing equipment for thermal vacuum reduction of alkali metals suffers from a deterioration in the system's background vacuum level after long-term use, resulting in a decrease in the purity and reduction rate of the alkali metals, which fails to meet the high requirements of vacuum filling in atomic gas chamber preparation. Summary of the Invention

[0005] This application provides a vacuum heating reduction preparation system for alkali metal elements, which helps to eliminate the gases generated by the reduction reaction, improve the ultimate vacuum of the system, and ensure the quality of the atomic gas chamber fabrication.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] On the one hand, this application provides a vacuum heating reduction preparation system for alkali metal elements, comprising:

[0008] A reaction vessel used to hold a mixture of alkali metal chlorides and reducing agents;

[0009] A glass vacuum apparatus includes a glass diffusion pump and a mechanical pump. One side of the glass diffusion pump is connected to the reaction vessel, and the other side is connected to the mechanical pump.

[0010] The heating device includes a first heating element and a second heating element. The first heating element is used to heat the mixture in the reaction vessel, and the second heating element is used to bake and degas the reaction vessel.

[0011] A temperature control device is electrically connected to the first heating element and the second heating element, and is used to control the heating temperature of the first heating element and the baking temperature of the second heating element.

[0012] As an optional implementation, a collection container is also included, with one side connected to the reaction vessel and the other side connected to a glass diffusion pump.

[0013] As an optional implementation, the reaction vessel includes:

[0014] A quartz tube is installed in the first heating element and is connected to the collection container;

[0015] The reaction tube is located inside a quartz tube;

[0016] The reaction boat is located inside the reaction tube;

[0017] The reaction boat is used to hold the mixture, and the reaction tube is used to introduce the alkali metals produced by the reaction into the collection container.

[0018] As an alternative implementation, the first heating element is opposite to the reaction boat to heat the mixture, and the second heating element is arranged around the quartz tube to bake and degas the quartz tube.

[0019] As an alternative implementation, the collection container includes an alkali metal collection tube, one end of which is connected to a quartz tube and the other end of which is connected to a glass vacuum device.

[0020] As an optional implementation, the alkali metal collecting tube and the quartz tube are connected by a multi-stage transition seal.

[0021] As an alternative implementation, the collection container also includes ampoules, with a sealing interface provided on the pipeline between the alkali metal collection tube and the glass vacuum device, and the ampoules connected to the sealing interface.

[0022] As an optional implementation, the sealing interface includes multiple components.

[0023] As an optional implementation, the reaction boat is provided with a reaction chamber for containing the mixture;

[0024] The reaction chamber is equipped with a heat-equalizing mesh covering the mixture;

[0025] The reaction boat has an opening at one end facing the collection container, and the opening is connected to the reaction chamber.

[0026] As an alternative implementation, the reaction tube is provided with a flow guide groove, one end of which extends toward the reaction boat and the other end extends toward the connection between the quartz tube and the collection container.

[0027] As an alternative implementation, the glass diffusion pump is connected to the collection container via a pipeline equipped with a flow regulating valve.

[0028] As an optional implementation, a protective gas filling device is also included, which is connected to the pipeline between the glass diffusion pump and the collection container.

[0029] As an optional implementation, the protective gas filling device includes a breakable valve and an argon gas source. The argon gas source is connected to the collection container via a pipeline, and the pipeline is equipped with a breakable valve.

[0030] As an optional implementation, it also includes multiple vacuum measuring devices, which are connected in series on the pipeline between the protective gas filling device and the collection container.

[0031] As an alternative implementation, the measurement ranges of the multiple vacuum measuring instruments are different.

[0032] As an alternative implementation, a condensation device is connected between the glass diffusion pump and the flow control valve.

[0033] As an optional implementation, the glass vacuum device also includes a pressure sensor located in the pipeline between the glass diffusion pump and the mechanical pump.

[0034] As an alternative implementation, the glass vacuum device also includes a buffer located in the pipeline between the pressure sensor and the glass diffusion pump.

[0035] This application provides a vacuum heating reduction preparation system for alkali metal elements. By connecting a reaction vessel and a glass diffusion pump in a glass vacuum apparatus, a first heating element heats the mixture in the reaction vessel, while a second heating element bakes and degassssss the reaction vessel. The first and second heating elements are controlled by a temperature control device. During the pre-reaction heating, vacuum degassing, and high-vacuum reactant generation stages, the glass diffusion pump serves as the main pump, which facilitates the removal of gases from the system before the reaction and those generated during the reduction reaction, thus improving the system's ultimate vacuum. Simultaneously, the glass vacuum apparatus exhibits significantly enhanced resistance to alkali metal vapor corrosion compared to metal vacuum apparatuses, resulting in minimal decrease in the system's vacuum level over long-term use. This system can stably prepare high-purity alkali metal elements suitable for vacuum filling of atomic clock atomic chambers, solving the current problem of obtaining high-quality alkali metal raw materials in the research and production of quantum frequency standards, thereby improving the manufacturing quality and technical specifications of atomic chambers. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of the vacuum heating reduction preparation system for alkali metal elements provided in the embodiments of this application;

[0038] Figure 2 for Figure 1 The diagram shows the structural structure of the reaction vessel in the vacuum heating reduction preparation system for alkali metal elements.

[0039] Explanation of reference numerals in the attached figures:

[0040] 100-Vacuum heating reduction preparation system for alkali metal elements; 10-Reaction vessel; 11-Quartz tube; 12-Reaction tube; 13-Reaction boat; 20-Collection container; 21-Alkali metal collection tube; 22-Ampoule; 23-Sealing interface; 30-Glass vacuum device; 31-Glass diffusion pump; 32-Mechanical pump; 33-Flow regulating valve; 34-Condensation equipment; 35-Pressure sensor; 36-Buffer; 40-Heating equipment; 41-First heating element; 411-Heating chamber; 42-Second heating element; 50-Protective gas filling device; 51-Breakable valve; 52-Argon gas source; 53-Vacuum measuring instrument. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0042] Alkali metals (rubidium or cesium) are the main working materials in the atomic gas chambers of quantum frequency standards and quantum sensors, and need to be encapsulated in a glass gas chamber with a specific buffer gas. Because quantum devices have high technical requirements, and alkali metals are physically and chemically highly reactive, filling and precisely controlling the mass of the alkali metal and the pressure of the buffer gas in a vacuum environment has become one of the main process and technical challenges in the preparation of atomic gas chambers.

[0043] Alkali metals, as widely used industrial products, are typically stored and transported in chloride form. During use, thermal vacuum reduction equipment is required. Under ultra-high vacuum conditions, the chlorides are heated to 500–700°C, reduced and purified, and then dispensed into glass ampoules for later use.

[0044] Existing equipment for thermal vacuum reduction of alkali metals suffers from a deterioration in the system's background vacuum level after long-term use, resulting in a decrease in the purity and reduction rate of the alkali metals, which fails to meet the high requirements of vacuum filling in atomic gas chamber preparation.

[0045] To overcome the shortcomings of existing technologies, after repeated consideration and verification, the inventors discovered that using a glass vacuum device in the preparation apparatus can reduce the corrosive effect of alkali metal vapors and improve the long-term stability of the system. At the same time, by using a high-speed glass diffusion pump connected to the system, the gases in the system before the reaction and the gases generated during the reduction reaction are removed by the glass diffusion pump, thereby increasing the ultimate vacuum of the system. This allows for the stable preparation of high-purity alkali metal elements that meet the requirements for vacuum filling of atomic clock atomic chambers, improving the manufacturing quality and technical specifications of the atomic chambers.

[0046] In view of this, this application provides a vacuum heating reduction preparation system for alkali metal elements, comprising:

[0047] A reaction vessel used to hold a mixture of alkali metal chlorides and reducing agents;

[0048] A glass vacuum apparatus includes a glass diffusion pump and a mechanical pump. One side of the glass diffusion pump is connected to the reaction vessel, and the other side is connected to the mechanical pump.

[0049] The heating device includes a first heating element and a second heating element. The first heating element is used to heat the mixture in the reaction vessel, and the second heating element is used to bake and degas the reaction vessel.

[0050] A temperature control device is electrically connected to the first heating element and the second heating element, and is used to control the heating temperature of the first heating element and the baking temperature of the second heating element.

[0051] By connecting the reaction vessel and the glass diffusion pump of the glass vacuum device, the mixture in the reaction vessel is heated by the first heating element, and the reaction vessel is baked and degassed by the second heating element. The first and second heating elements are controlled by a temperature control device. The glass diffusion pump is used as the main pump in the heating vacuum degassing and high-vacuum reactant generation stages before the reaction starts. This is beneficial for removing gases in the system before the reaction and gases generated during the reduction reaction, improving the ultimate vacuum of the system. It can reduce alkali metals from chlorides to high-purity elemental metals. At the same time, the glass vacuum device has significantly enhanced resistance to alkali metal vapor corrosion than the metal vacuum device. The vacuum degree of the system decreases less after long-term use. It can stably prepare high-purity elemental alkali metals that meet the requirements of vacuum filling of atomic clock atomic gas chambers, solving the problem of obtaining high-quality alkali metal raw materials in the current research and production of quantum frequency standards, thereby improving the manufacturing quality and technical indicators of atomic gas chambers.

[0052] The contents of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can have a clearer and more detailed understanding of the contents of this application.

[0053] Figure 1 This is a schematic diagram of the structure of the vacuum heating reduction preparation system for alkali metal elements provided in the embodiments of this application. Figure 2 for Figure 1 The diagram shows the structural structure of the reaction vessel in the vacuum heating reduction preparation system for alkali metal elements.

[0054] like Figure 1 As shown, the vacuum heating reduction preparation system 100 for alkali metal elements provided in this application embodiment is used to prepare high-purity alkali metal elements, such as rubidium or cesium, for use in the filling process of quantum frequency standard atomic gas cells.

[0055] The vacuum heating reduction preparation system 100 for alkali metal elements includes a reaction vessel 10, a collection vessel 20, a glass vacuum device 30, a heating device 40, and a temperature control device. The reaction vessel 10 is the main site for the chemical reaction, used to hold the mixture of alkali metal chloride and reducing agent, thereby ensuring the smooth progress of the reaction and preventing interference from external contaminants. The collection vessel 20 is connected to the reaction vessel 10 and is used to collect the alkali metal elements produced in the reaction. The glass vacuum device 30 is connected to the collection vessel 20 and is used to provide a low-pressure vacuum environment to promote the reaction, prevent other adverse reactions, and improve the purity of the alkali metal elements. The heating device 40 is used to heat the reaction vessel 10 to increase its temperature, thereby providing the energy required for the reaction, improving reaction efficiency and the quality of the alkali metal elements. The temperature control device is used to control the heating device 40 to precisely control the temperature, ensuring the reaction proceeds under optimal conditions, preventing overheating or underheating, and improving the repeatability and safety of the reaction.

[0056] In one possible implementation, the glass vacuum device 30 includes a glass diffusion pump 31 and a mechanical pump 32. One side of the glass diffusion pump 31 is connected to the collection container 20, and the other side is connected to the mechanical pump 32. The combination of the glass diffusion pump 31 and the mechanical pump 32 can maintain the vacuum level required for the reaction, thereby promoting the reaction.

[0057] Please also refer to Figure 2 In one possible implementation, the heating device 40 includes a first heating element 41 and a second heating element 42. The reaction vessel 10 is disposed in the first heating element 41, which is used to heat the mixture in the reaction vessel 10. The second heating element 42 is used to bake and degas the reaction vessel 10 to remove residual gas and moisture and prevent other reactions from occurring.

[0058] The temperature control device is electrically connected to the first heating element 41 and the second heating element 42, and is used to control the heating temperature of the first heating element 41 and the baking temperature of the second heating element 42.

[0059] By connecting the collection container 20 to the reaction container 10 and the glass diffusion pump 31 of the glass vacuum device 30, the mixture in the reaction container 10 is heated by the first heating element 41, and the reaction container 10 is baked and degassed by the second heating element 42. The first heating element 41 and the second heating element 42 are controlled by the temperature control device. In the stages of heating, vacuum degassing and high vacuum reactant generation before the reaction, the glass diffusion pump 31 is used as the main pump, which is beneficial to remove the gas in the system before the reaction and the gas generated during the reduction reaction, thereby improving the ultimate vacuum of the system. At the same time, the glass vacuum device 30 has a significantly enhanced resistance to alkali metal vapor corrosion than the metal vacuum device. After long-term use, the vacuum of the system decreases little. The process is reliable and can stably prepare high-purity alkali metal elements that meet the requirements of vacuum filling of atomic clock atomic gas chambers. This solves the problem of obtaining high-quality alkali metal raw materials in the current research and production of quantum frequency standards, thereby improving the manufacturing quality and technical indicators of atomic gas chambers.

[0060] In one possible implementation, calcium hydride is used as the reducing agent for alkali metal chlorides, and hydrogen gas is generated during the reaction. The reduction reaction of alkali metals mainly consists of three stages: heating and vacuum degassing, hydrogen production from the reactants at low temperature, and the formation of alkali metals from the reactants under high vacuum.

[0061] The combination of glass diffusion pump 31 and mechanical pump 32 enables the completion of three stages in the reaction process: heating and vacuum degassing, hydrogen removal from low-temperature reactants, and alkali metal formation from high-vacuum reactants. During the low-temperature distillation process, glass diffusion pump 31 helps to remove the large amount of hydrogen produced by the reduction reaction, thereby increasing the system's ultimate vacuum.

[0062] The temperature control device adjusts the heating rate and heating time according to the process of the reduction reaction and the changes in the system vacuum, so as to control the effective progress of each stage of the reaction. During the alkali metal collection process, by setting the temperature gradient of the reaction vessel 10, the alkali metal elements generated by the reaction are completely deposited in the collection vessel 20.

[0063] like Figure 2 As shown, in one optional embodiment, the first heating element 41 is provided with a heating chamber 411, which is opened in a horizontal direction, and the reaction vessel 20 is horizontally disposed in the heating chamber 411.

[0064] The horizontally placed reaction vessel 20 achieves a more uniform heat distribution within the heating chamber 411, reducing the risk of localized overheating or overcooling, thereby improving reaction uniformity and efficiency. The horizontally placed reaction vessel 20 is also more stable during heating, reducing the risk of tipping or movement and improving operational safety. The horizontal design reduces vertical heat loss, improving heating efficiency and lowering energy consumption.

[0065] As an optional implementation, the first heating element 41 is a horizontal electric furnace, which can move horizontally via a hinge device. The horizontal movement distance is set to 300mm, and one end is open. The furnace body is cylindrical, with a length of 300mm, and the diameter of the furnace chamber, i.e., the diameter of the heating cavity 411, is 40mm; the power is 3000W. The maximum temperature is 800℃. The inner and outer layers are clad with stainless steel plates, and the middle is filled with heat insulation material. The thermocouple socket is located in the middle of the cavity wall of the heating cavity 411. The furnace temperature is controlled by a PID controller with a temperature control accuracy of ±1℃.

[0066] The temperature control device is electrically connected to the first heating element 41 and the second heating element 42 respectively. The maximum temperature of the electric furnace is 800℃, and the maximum temperature of the second heating element 42 is 300℃. The temperature control accuracy is ±1℃.

[0067] As an optional implementation, the reaction vessel 10 includes a quartz tube 11, a reaction tube 12, and a reaction boat 13. The quartz tube 11 is disposed in the first heating element 41 and is connected to the collection container 20. The reaction tube 12 is disposed in the quartz tube 11, and the reaction boat 13 is disposed in the reaction tube 12. The reaction boat 13 is used to hold the mixture, and the reaction tube 12 is used to introduce the alkali metal generated by the reaction into the collection container 20.

[0068] The first heating element 41 is opposite to the reaction boat 13 to heat the mixture, and the second heating element 42 is arranged around the quartz tube 11 to bake and degas the quartz tube 11.

[0069] Since the reduction reaction of alkali metals is completed at 500℃~700℃, ordinary glass will soften and deform above 400℃. Quartz tube 11 has excellent heat resistance and chemical corrosion resistance, and can withstand high temperature heating without deformation or releasing impurities, thus protecting the reaction mixture from interference. Therefore, high temperature resistant quartz glass is selected as the reaction site.

[0070] Nickel has good corrosion resistance and high temperature stability, making it suitable for processing alkali metals and other reactive substances. It can effectively resist the corrosion of alkali metals. Therefore, nickel reaction tubes and nickel boats are selected for the reaction, but it is not limited to this. In other embodiments, other corrosion-resistant and high-temperature-resistant materials such as stainless steel can also be used.

[0071] By introducing the alkali metal generated by the reaction into the collection container 20 through the reaction tube 12, the effective transfer and collection of the alkali metal can be ensured, reducing the probability of the alkali metal coming into contact with the quartz tube 11 and reacting. This prevents the high-temperature alkali metal vapor from reacting after contacting the quartz tube 11, thus reducing loss and pollution.

[0072] As an optional implementation, the reaction boat 13 is provided with a reaction chamber for containing the mixture. The reaction chamber is provided with a heat exchange net covering the mixture. The reaction boat 13 has an opening at one end facing the collection container 20, and the opening communicates with the reaction chamber.

[0073] The opening at one end of the reaction vessel 13 allows the generated gases or vapors to escape smoothly, reducing pressure buildup within the reaction chamber and thus accelerating the reaction process. The opening connects to the reaction chamber, enabling the generated alkali metal vapors to flow directly to the collection container 20, reducing alkali metal loss and contamination during transport. A heat-equalizing mesh covering the mixture helps to evenly distribute heat, prevents material splashing in the initial stages of the reaction, ensures uniform heating of the mixture during the reaction, and improves reaction efficiency and consistency.

[0074] As an optional implementation, a fine-mesh nickel mesh is used for the heat exchanger.

[0075] As an optional implementation, the reaction tube 12 is provided with a flow guide groove, one end of which extends toward the reaction boat 13 and the other end extends toward the connection between the quartz tube 11 and the collection container 20.

[0076] The flow channel provides a clear flow path for the gas or vapor generated by the reaction, reducing turbulence and stagnation within the quartz tube 11, thereby improving transmission efficiency. Through the directional flow design of the flow channel, the generated alkali metal vapor can be more effectively guided to the collection container 20, reducing vapor loss and condensation during transmission. The presence of the flow channel accelerates gas transfer, reduces the possibility of side reactions or adverse reactions with the quartz tube 11, and improves the purity of the alkali metal.

[0077] The quartz tube 11 containing the reaction tube 12 is placed in a horizontally sliding electric furnace. The heating section of the reaction tube 12 can be controlled by adjusting the temperature and horizontal distance of the electric furnace. This allows the liquid alkali metal generated by the reaction to migrate along the guide channel to the cold end, i.e., the collection container 20, under the influence of temperature.

[0078] As an optional implementation, the collection container 20 includes an alkali metal collection tube 21, one end of which is connected to a quartz tube 11 and the other end is connected to a glass vacuum device 30.

[0079] Specifically, one end of the alkali metal collecting tube 21 is transitionally connected to the quartz tube 11, while the other end of the alkali metal collecting tube 21 is connected to the glass diffusion pump 31 through a glass tube.

[0080] Optionally, the alkali metal collecting tube 21 is made of borosilicate hard glass.

[0081] High borosilicate glass exhibits excellent corrosion resistance to most chemicals and is able to resist the erosion of alkali metals, ensuring the long service life and reliability of the collection container 20. Furthermore, the transparency of high borosilicate glass allows operators to observe the state and location of alkali metals during the collection process, facilitating monitoring and adjustments to the operation and ensuring the accuracy of the collection process.

[0082] When collecting alkali metals, the bottom of the alkali metal collecting tube 21 is cooled by a water bath, thereby cooling the alkali metals and accumulating them in the alkali metal collecting tube 21.

[0083] As an optional implementation, the alkali metal collecting tube 21 and the quartz tube 11 are connected in a multi-stage transition seal.

[0084] Because the reaction vessel 10 requires high-temperature resistant quartz glass, while the collection vessel 20 for alkali metals such as rubidium uses ordinary glass or borosilicate glass, and their coefficients of thermal expansion differ by an order of magnitude, a transition connection is needed between the alkali metal collection tube 21 and the quartz tube 11. Since different materials have different coefficients of thermal expansion, direct connection may lead to stress and cracking under temperature changes. A multi-stage transition seal can gradually bridge the difference in thermal expansion between the materials, reducing thermal stress and improving the system's durability and reliability. The multi-stage transition seal also provides better sealing performance, preventing gas leakage and the entry of external contaminants into the system, ensuring the stability of the vacuum environment and the purity of the reaction. Through the multi-stage transition seal, the mechanical strength of the connection is enhanced, enabling it to better withstand physical stress and vibration during operation and reducing the risk of breakage.

[0085] As an optional implementation, the collection container 20 also includes an ampoule 22, and at least one sealing port 23 is provided on the pipeline between the alkali metal collection tube 21 and the glass vacuum device 30, with the ampoule 22 connected to the sealing port 23.

[0086] As an optional implementation, the sealing interface 23 includes multiple interfaces.

[0087] Ampoule 22 provides a sealed environment for the safe storage and protection of collected alkali metals, preventing contact with oxygen and moisture in the air and thus avoiding oxidation and reactions. The use of Ampoule 22 effectively isolates alkali metals, reducing the risk of contaminants entering the collection system and ensuring high product purity. Ampoule 22 are typically small, sealed containers, facilitating transportation and storage, and are particularly suitable for laboratory and industrial applications requiring use or storage in various locations, such as in the fabrication of atomic gas chambers.

[0088] By reserving sealing interfaces 23, ampoules 22 can be easily connected and disconnected, allowing for the dispensing and transfer of alkali metals without compromising the overall system vacuum. The sealing interfaces 23 allow for flexible replacement of ampoules 22 at different experimental and production stages, adapting to varying operational needs and improving system adaptability. By reserving multiple breakable sealing interfaces 23 for each ampoule 22, the number of ampoules 22 can be arranged according to the amount of alkali metal produced.

[0089] After the alkali metal reacts, the portion of the quartz tube 11 outside the electric furnace is heated by the second heating element 42, and the temperature is controlled. The alkali metal collecting tube 21 below the quartz tube 11 is cooled by a cold water bath (water bath temperature 10°C). The liquid alkali metal that accumulates at the low-temperature end of the quartz tube 11 is eventually collected into the alkali metal collecting tube 21 at the cold end under the action of gravity and the pressure inside the quartz tube 11. Multiple sealing interfaces 23 capable of breaking ampoules 22 are reserved in the glass section between the alkali metal collecting tube 21 and the glass diffusion pump 31. The number of ampoules 22 can be arranged according to the amount of alkali metal encapsulated in each ampoule 22 after the alkali metal reacts, thereby producing high-purity alkali metal that meets the purity requirements for atomic gas chamber production.

[0090] As an optional implementation, the glass diffusion pump 31 is connected to the collection container 20 via a pipeline, and a flow regulating valve 33 is provided on the pipeline.

[0091] By adjusting the flow regulating valve 33, the gas flow rate entering the glass diffusion pump 31 can be precisely controlled, thereby regulating the vacuum pumping speed, maintaining stable system pressure, preventing excessively rapid pressure changes within the collection container 20, protecting the container and its internal materials from pressure shocks, and reducing the risk of breakage. Adjusting the flow rate can reduce the workload of the glass diffusion pump 31 when unnecessary, reducing energy consumption and extending the pump's service life.

[0092] As an optional implementation, the flow regulating valve 33 is a glass ball valve.

[0093] Ball valves are simple in structure, wear-resistant, and suitable for frequent operation. They maintain good performance even under high pressure and high temperature conditions, and offer excellent sealing performance in both fully open and fully closed states, reducing the risk of fluid leakage. Furthermore, in the fully open state, ball valves exhibit almost no flow resistance, allowing fluid to flow smoothly, reducing energy loss and improving system efficiency.

[0094] As an alternative implementation, calcium hydride, the reducing agent in the reactants, readily absorbs water vapor and caking under natural conditions. The vacuum heating reduction preparation system 100 for alkali metal elements also includes a protective gas charging device 50. The protective gas charging device 50 is connected to the pipeline between the glass diffusion pump 31 and the collection container 20.

[0095] By using the protective gas filling device 50, an inert gas (such as argon or nitrogen) can be introduced into the system before the reaction begins, forming a protective atmosphere within the system to prevent oxygen and moisture from entering the collection container 20 and the reaction container 10, thereby avoiding oxidation and hydrolysis of the mixture.

[0096] Taking the reduction reaction of alkali metal rubidium as an example, the weighed and proportioned reactants (a mixture of calcium hydride and rubidium chloride) are first finely ground in an agate mill and placed in a constant temperature drying oven (temperature set at 150°C, time 2 hours) for drying pretreatment. Then, the reactants are loaded into the reaction boat 13 on a clean workbench under argon protection and covered with a fine-mesh nickel mesh, and then placed in the reaction tube 12 with a guide groove. During the process of filling the reaction tube 12 into the quartz tube 11 and sealing the quartz tube 11 and the alkali metal collection tube 21 with glass, the reactants will inevitably absorb moisture or oxidize and degenerate in the atmospheric environment. Therefore, a protective gas filling device 50 is set up. When the vacuum device is temporarily closed, argon is introduced into the system through the protective gas filling device 50, and the filling and glass sealing are carried out in an argon protective atmosphere.

[0097] As an optional implementation, the protective gas filling device 50 includes a breakable valve 51 and an argon gas source 52. The argon gas source 52 is connected to the collection container 20 via a pipeline, on which the breakable valve 51 is installed.

[0098] To prevent the reactants from absorbing moisture or oxidizing during the filling process, an argon gas filling port with a breakable valve 51 is designed. When the vacuum device is temporarily closed, argon gas can be filled in through the argon gas source 52, and the filling of materials and sealing of glass can be carried out in an argon protective atmosphere.

[0099] By installing a breakable valve 51 on the pipeline between the flow regulating valve 33 and the collection container 20, the system can quickly switch to the protection mode before the reaction starts. Argon gas is quickly introduced through the argon gas source 52 to form a protective atmosphere in the collection container 20 and the reaction container 10, preventing external air and moisture from entering the system and maintaining the purity of the raw materials.

[0100] As an optional implementation, it also includes a plurality of vacuum measuring devices 53, which are connected in series in the pipeline between the protective gas filling device 50 and the collection container 20.

[0101] The vacuum gauge 53 provides real-time vacuum readings, enabling operators to accurately understand the internal pressure of the system and ensure that reaction conditions are within the expected range. By monitoring the vacuum level, reaction conditions can be adjusted in a timely manner to optimize the reaction rate and product quality, thereby improving the efficiency of experiments and production.

[0102] As an alternative implementation, the multiple vacuum measuring instruments 53 have different measuring ranges.

[0103] As an optional implementation, the vacuum measuring instrument 53 employs a Pirani gauge and an ionization gauge to improve the accuracy of the measurement of the system vacuum level.

[0104] As an optional implementation, a condensation device 34 is connected between the glass diffusion pump 31 and the flow regulating valve 33.

[0105] The condenser 34 can convert certain condensable gases or vapors in the system into liquids, such as alkali metals, thereby reducing the burden of these gases on the glass vacuum device 30 and improving the efficiency of the glass diffusion pump 31 and the overall vacuum level.

[0106] As an optional implementation, the condensation device 34 employs a liquid nitrogen cold trap. The liquid nitrogen cold trap prevents the backflow of diffusion pump oil vapor, reducing pump oil contamination and the amount of impurities mixed in with the alkali metal. Simultaneously, the liquid nitrogen cold trap can condense the alkali metal vapor, preventing it from entering the glass diffusion pump 31.

[0107] Liquid nitrogen cold traps can reach extremely low temperatures, effectively condensing and capturing most volatile substances and vapors in the system, thus improving condensation efficiency. By condensing and removing condensable gases, liquid nitrogen cold traps can reduce the gas load in vacuum devices, thereby increasing the ultimate vacuum level of the system. Liquid nitrogen cold traps can capture and condense volatile compounds, preventing these substances from entering the vacuum pump, reducing pump contamination and wear, and extending its service life.

[0108] As an optional implementation, two glass diffusion pumps 31 are included, and the two glass diffusion pumps 31 are connected in series.

[0109] The series connection of glass diffusion pumps 31 can significantly improve the system's pumping capacity and achieve a higher vacuum level. Simultaneously, the series connection of glass diffusion pumps 31 can distribute the load more evenly, reducing pressure fluctuations in individual glass diffusion pumps 31, thereby improving system stability and reliability. By reducing pressure in stages, the series connection of glass diffusion pumps 31 can more effectively handle gases in different pressure ranges, improving overall pumping efficiency.

[0110] As an optional implementation, the glass diffusion pump 31 is a four-stage glass diffusion pump.

[0111] The four-stage design allows the glass diffusion pump 31 to progressively reduce pressure, with each stage further removing gas, thus providing a greater pumping speed and achieving a higher ultimate vacuum. The multi-stage pump design helps balance pressure fluctuations, providing a more stable and continuous vacuum environment. It also effectively reduces backflow of diffusion pump oil or other fluids, protecting the system and products from contamination.

[0112] As an optional implementation, the glass vacuum device 30 also includes a pressure sensor 35, which is located in the pipeline between the glass diffusion pump 31 and the mechanical pump 32.

[0113] Pressure sensor 35 provides real-time pressure readings, enabling operators to accurately understand the pressure conditions within the system and ensure that the glass vacuum unit 30 operates within the expected operating range.

[0114] As an optional implementation, pressure sensor 35 employs a Pirani gauge.

[0115] As an optional implementation, the glass vacuum device 30 also includes a buffer 36, which is located in the pipeline between the pressure sensor 35 and the glass diffusion pump 31.

[0116] The buffer 36 can absorb and mitigate instantaneous pressure fluctuations in the system, providing a more stable pressure environment and protecting system components from pressure shocks. At the same time, the use of the buffer 36 helps to provide more stable pressure readings, improve the measurement accuracy of the pressure sensor 35, and ensure that the system operates under optimal conditions.

[0117] As an alternative implementation, the buffer 36 is a 2L spherical glass container.

[0118] The following example, using the reduction of rubidium chloride by calcium hydride, illustrates the process flow of the entire alkali metal element vacuum heating reduction preparation system 100 for producing alkali metals.

[0119] The reduction reaction of rubidium chloride is mainly divided into three stages: heating and vacuum degassing, low-temperature hydrogen extraction from reactants, and high-vacuum rubidium extraction. In the experiment, the heating rate and heating time were adjusted according to the changes in the system vacuum to control the effective progress of each stage of the reaction. During the rubidium collection process, a temperature gradient was set in the reaction tube to ensure that the metallic rubidium generated by the reaction was completely deposited in the alkali metal collection tube 21.

[0120] First, the mixture of calcium hydride and rubidium chloride is weighed, ground, and dried according to the molar ratio for the reduction reaction, and then loaded into the cleaned reaction boat 13. Under the protection of high-purity argon gas, the reaction tube 12 and the reaction boat 13 containing the reactants are loaded into the quartz tube 11, and then the mixture is transferred to the alkali metal collecting tube 21 by a glass lamp.

[0121] The glass vacuum device 30 and the electric furnace heating and temperature control device are turned on to bake and degas the quartz tube 11, entering the heating vacuum degassing stage to improve the system vacuum degree and cleanliness. The heating rate in this stage is 10℃ / min.

[0122] When the temperature reaches 200℃, the low-temperature reactant hydrogen release stage begins, and the heating rate is reduced to 2℃ / min to allow the material to slowly release hydrogen. If the temperature increases too quickly, a large amount of hydrogen will be released from the reactants, causing a sharp deterioration in the vacuum level and material splashing. The pumping speed can be controlled by adjusting the opening size of the glass ball valve. When the temperature reaches 400℃, the low-temperature reactant hydrogen release ends, and the heating rate can be increased to 5-10℃ / min.

[0123] When the temperature reaches approximately 620℃, the reduction reaction begins, entering the high-vacuum rubidium extraction stage. Metallic rubidium is generated and condenses on the inner surface of the cold end of the quartz tube 11. The heating rate is then gradually reduced to 2℃ / min to ensure all rubidium is uniformly cooled into the alkali metal collecting tube 21. The melting point of the reactant rubidium chloride is 715℃, and the melting point of the reaction product calcium chloride is 775℃. To ensure that the collected rubidium does not contain calcium chloride or rubidium chloride, the maximum reaction temperature is controlled below 710℃.

[0124] Finally, the glass tube is cut off at the narrowing point of the alkali metal collecting tube 21, and the alkali metal collecting tube 21 and the ampoule 22 are removed from the quartz tube 11 and the glass vacuum device 30. Then, a flexible flame is used to drive the rubidium metal in the alkali metal collecting tube 21 into the multiple ampoules 22.

[0125] The vacuum heating reduction preparation system 100 for alkali metal elements provided in this application includes a reaction vessel 10, a glass vacuum device 30, a heating device 40, and a temperature control device. The reaction vessel 10 is used to hold a mixture of alkali metal chloride and a reducing agent. The glass vacuum device 30 includes a glass diffusion pump 31 and a mechanical pump 32. One side of the glass diffusion pump 31 is connected to the reaction vessel 10, and the other side is connected to the mechanical pump 32. The heating device 40 includes a first heating element 41 and a second heating element 42. The first heating element 41 is used to heat the mixture in the reaction vessel 10, and the second heating element 42 is used to bake and degas the reaction vessel 40. The temperature control device is electrically connected to the first heating element 41 and the second heating element 42, and is used to control the heating temperature of the first heating element 41 and the baking temperature of the second heating element 42.

[0126] By connecting the reaction vessel 10 and the glass diffusion pump 31 of the glass vacuum device 30, the mixture in the reaction vessel 10 is heated by the first heating element 41, and the reaction vessel 10 is baked and degassed by the second heating element 42. The first heating element 41 and the second heating element 42 are controlled by the temperature control device. In the stages of heating, vacuum degassing and high vacuum reactant generation before the reaction starts, the glass diffusion pump 31 is used as the main pump. This is beneficial for removing the gas in the system before the reaction and the gas generated during the reduction reaction, thereby improving the ultimate vacuum of the system. At the same time, the glass vacuum device 30 has a significantly enhanced resistance to alkali metal vapor corrosion than the metal vacuum device. The vacuum level of the system decreases less after long-term use. It can stably prepare high-purity alkali metal elements that meet the requirements of vacuum filling of atomic clock atomic gas chambers, solve the problem of obtaining high-quality alkali metal raw materials in the current research and production of quantum frequency standards, and thus improve the manufacturing quality and technical indicators of atomic gas chambers.

[0127] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0128] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0129] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on something” but also “on something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0130] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A vacuum heating reduction preparation system for alkali metal elements, characterized in that, include: The reaction vessel (10) is used to hold a mixture of alkali metal chloride and reducing agent. The reaction vessel (10) includes a quartz tube (11), a reaction tube (12), and a reaction boat (13). The glass vacuum device (30) includes a glass diffusion pump (31) and a mechanical pump (32). One side of the glass diffusion pump (31) is connected to the reaction vessel (10), and the other side is connected to the mechanical pump (32). The collection container (20) includes an alkali metal collection tube (21) and an ampoule (22). One end of the alkali metal collection tube (21) is connected to the quartz tube (11), and the other end is connected to the glass diffusion pump (31). The alkali metal collection tube (21) is a high borosilicate glass tube and is multi-stage transition sealed to the quartz tube (11). A sealing interface (23) is provided on the pipeline between the alkali metal collection tube (21) and the glass diffusion pump (31), and the ampoule (22) is connected to the sealing interface (23). The heating device (40) includes a first heating element (41) and a second heating element (42). The first heating element (41) is opposite to the reaction boat (13) and is used to heat the mixture in the reaction boat (13). The second heating element (42) is arranged around the quartz tube (11) and is used to bake and degas the quartz tube (11) after the mixture is added. A temperature control device is electrically connected to the first heating element (41) and the second heating element (42) for controlling the heating temperature of the first heating element (41) and the baking temperature of the second heating element (42); The quartz tube (11) is located in the first heating element (41); the reaction tube (12) is located in the quartz tube (11) and is used to introduce the alkali metal generated by the reaction into the collection container (20); the reaction tube (12) is provided with a guide groove, one end of which extends toward the reaction boat (13) and the other end extends toward the connection between the quartz tube (11) and the alkali metal collection tube (21); the reaction boat (13) is located in the reaction tube (12) and is used to place the mixture.

2. The vacuum heating reduction preparation system for alkali metal elements according to claim 1, characterized in that, The sealing interface (23) includes multiple interfaces.

3. The vacuum heating reduction preparation system for alkali metal elements according to claim 1, characterized in that, The reaction boat (13) is provided with a reaction chamber for containing the mixture. The reaction chamber is equipped with a heat-equalizing mesh covering the mixture; The reaction boat (13) has an opening at one end facing the collection container (20), and the opening is connected to the reaction chamber.

4. The vacuum heating reduction preparation system for alkali metal elements according to any one of claims 1-3, characterized in that, The glass diffusion pump (31) is connected to the collection container (20) via a pipeline, and a flow regulating valve (33) is installed on the pipeline.

5. The vacuum heating reduction preparation system for alkali metal elements according to any one of claims 1-3, characterized in that, It also includes a protective gas filling device (50), which is connected to the pipeline between the glass diffusion pump (31) and the collection container (20).

6. The vacuum heating reduction preparation system for alkali metal elements according to claim 5, characterized in that, The protective gas filling device (50) includes a breakable valve (51) and an argon gas source (52). The argon gas source (52) is connected to the collection container (20) through a pipeline, and the breakable valve (51) is provided on the pipeline.

7. The vacuum heating reduction preparation system for alkali metal elements according to claim 5, characterized in that, It also includes multiple vacuum measuring devices (53), which are connected in series on the pipeline between the protective gas filling device (50) and the collection container (20).

8. The vacuum heating reduction preparation system for alkali metal elements according to claim 7, characterized in that, The various vacuum measuring instruments (53) have different measurement ranges.

9. The vacuum heating reduction preparation system for alkali metal elements according to claim 4, characterized in that, A condenser (34) is connected between the glass diffusion pump (31) and the flow regulating valve (33).

10. The vacuum heating reduction preparation system for alkali metal elements according to any one of claims 1-3, characterized in that, The glass vacuum device (30) also includes a pressure sensor (35), which is located on the pipeline between the glass diffusion pump (31) and the mechanical pump (32).

11. The vacuum heating reduction preparation system for alkali metal elements according to claim 10, characterized in that, The glass vacuum device (30) also includes a buffer (36), which is located on the pipeline between the pressure sensor (35) and the glass diffusion pump (31).

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