Purification system for metallic cesium

Abstract

Embodiments of the present application relate to a cesium metal purification system, belonging to the technical field of metal purification. The cesium metal purification system comprises: a supply device adapted to provide cesium raw material; a heating evaporation device adapted to heat and evaporate the cesium raw material from the supply device to obtain purified cesium vapor; and a condensing device arranged above the heating evaporation device and in communication with the heating evaporation device, adapted to condense the cesium vapor from the heating evaporation device and return to the heating evaporation device to realize multiple evaporation and condensation of the cesium raw material. The condensing device comprises: a first condenser adapted to condense a first part of the cesium vapor from the heating evaporation device into a first liquid and return to the heating evaporation device; and a second condenser arranged above the first condenser and adapted to condense a second part of the cesium vapor rising from the first condenser into a second liquid, the second liquid returning to the heating evaporation device through the first condenser.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to a metal purification system, specifically to a purification system for metallic cesium. Background Technology

[0002] Cesium, a metallic alkali metal, has a low melting point and relatively high saturated vapor pressure, exhibiting good electrical and thermal conductivity and ductility. Cesium is chemically extremely reactive, readily reacting with oxygen to form a series of oxides, and reacting violently with water, resulting in an explosion. As a paramagnetic substance, cesium, due to its large atomic weight and extremely low electron work function and ionization energy, is widely used in research on cesium ion propulsion engines and thermionic energy converters.

[0003] At high temperatures, thermionic energy converters typically use refractory metals or alloys as electrodes. Cesium, due to its extremely low ionization energy, is considered the most promising material for generating low-temperature plasma in thermionic energy converters. By utilizing the adsorption and ionization of cesium and matching it with refractory metal or alloy electrodes, the performance of thermionic energy converters can be significantly improved. When using metallic cesium as the working medium, high purity is required. This is because reduced cesium purity directly affects the thermoelectric conversion performance of thermionic energy conversion and also impacts the chemical stability of the high-temperature electrodes, reducing electrode lifespan.

[0004] In related technologies, distillation is often carried out by integrating the heating evaporation device and the condensation device. This allows cesium vapor to evaporate from the evaporation surface, condense in the condenser tube, and enter the collector through the material collection port. This method cannot achieve repeated distillation of cesium, so there is still room for improvement in the purity of the prepared cesium, which is not suitable for the requirements of thermionic energy converters, etc.

[0005] In summary, there is a need to construct a cesium purification system that can further purify cesium and make it suitable for applications such as thermionic energy converters that require high cesium purity. Summary of the Invention

[0006] To address at least one or more of the aforementioned technical problems, embodiments of the present invention provide a cesium metal purification system. By separating the condensation device from the heating evaporation device, and further dividing the condensation device into a first condenser and a second condenser, and using the first condenser and the second condenser in a vertical combination, multiple evaporations and condensations of the cesium raw material can be achieved, resulting in cesium with high purity.

[0007] This invention provides a cesium purification system, comprising: a supply device for supplying cesium raw materials; a heating and evaporation device for heating and evaporating the cesium raw materials from the supply device to obtain purified cesium vapor; and a condensation device connected to the heating and evaporation device for condensing the cesium vapor from the heating and evaporation device and returning it to the heating and evaporation device, thereby achieving multiple evaporation and condensation of the cesium raw materials. The condensation device includes: a first condenser for condensing a first portion of the cesium vapor from the heating and evaporation device into a first liquid and returning it to the heating and evaporation device; and a second condenser disposed above the first condenser for condensing a second portion of the cesium vapor rising from the first condenser into a second liquid, the second liquid returning to the heating and evaporation device through the first condenser.

[0008] The cesium purification system based on the above embodiments of the present invention separates the condensation device from the heating and evaporation device, and divides it into a first condenser and a second condenser. The first condenser and the second condenser are used in a vertical direction, so that the cesium liquid flows back into the heating and evaporation device by gravity. This facilitates the return of the condensed cesium to the heating and evaporation device through different paths, and facilitates the separation of other metal impurities and hydrides from the condensed cesium. By repeatedly heating, evaporating and condensing, the purification of cesium is achieved. Attached Figure Description

[0009] The present invention will be further described in detail below with reference to the accompanying drawings.

[0010] Figure 1 A block diagram of a cesium purification system according to an embodiment of the present invention is shown; and

[0011] Figure 2 It shows Figure 1 An enlarged schematic diagram of section C.

[0012] [Explanation of Labels in the Attached Image]

[0013] 1-Supply device;

[0014] 110-Cesium Bubble;

[0015] 120-Extractor;

[0016] 130-Filter;

[0017] 140 - Transfer device;

[0018] 2- Heating and evaporation device;

[0019] 3-Condensation unit;

[0020] 310 - Housing;

[0021] 320 - First condenser;

[0022] 321 - First column;

[0023] 3211 - Through hole;

[0024] 322 - First Helix;

[0025] 330 - Second condenser;

[0026] 331 - Second column;

[0027] 3311 - Conical shape;

[0028] 332 - Cooling components;

[0029] 3321 - Cooling pipe;

[0030] 333 - Second Helix;

[0031] 4-Vacuum device;

[0032] 410 - Oil-free composite molecular pump;

[0033] 420 - Mechanical pump;

[0034] 5-Inert gas apparatus;

[0035] 6-Cold trap;

[0036] 7-Collection device;

[0037] 8-First valve;

[0038] 9-Second valve;

[0039] 10-Third valve;

[0040] 11-Fourth valve;

[0041] 12-Transportation pipeline;

[0042] 13-Electrode chamber of the thermionic energy converter;

[0043] A - Cooling oil;

[0044] B - Cooling water. Detailed Implementation

[0045] In related technologies, the purification of metallic cesium often employs a three-stage vacuum distillation process. However, while this method can remove impurities of low vapor pressure metal elements, it cannot remove other impurities simultaneously. Furthermore, because the three-stage vacuum distillation apparatus is made of glass, it introduces new impurities, such as silicon, during the distillation process, thus affecting the purity of the purified cesium. In developing this invention, it was discovered that separating the condensation device from the heating and evaporation device, and dividing it into a first condenser and a second condenser, facilitates the separation of other metal impurities and hydrides from the condensed cesium.

[0046] Therefore, embodiments of the present invention provide a cesium purification system that can use cesium raw materials to undergo heating and evaporation to obtain cesium vapor, which is then condensed into liquid cesium upon reaching a condenser. By vertically arranging a first condenser and a second condenser, the liquid cesium flows back into the heating and evaporation device through different paths under the influence of gravity. This facilitates the separation of other metal impurities and hydrides from the condensed cesium, resulting in cesium with higher purity.

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0048] The endpoints and any values ​​of the ranges claimed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically claimed in this invention.

[0049] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0050] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0051] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. Where the terms "first," "second," etc., are used throughout the text, they are used only to distinguish similar objects and should not be construed as indicating or implying their relative importance, order of precedence, or implicitly specifying the number of technical features indicated. It should be understood that the data in the descriptions of "first," "second," etc., can be interchanged where appropriate.

[0052] Figure 1 A block diagram of a cesium purification system according to an embodiment of the present invention is shown.

[0053] The following combination Figure 1 A purification system for metallic cesium, as described in an embodiment of the present invention, will be described in detail.

[0054] According to some embodiments of the present invention, such as Figure 1 As shown, the cesium purification system provided in the embodiments of the present invention includes a supply device 1, a heating and evaporation device 2, and a condensation device 3. The supply device 1 is suitable for providing cesium raw materials. The heating and evaporation device 2 is suitable for heating and evaporating the cesium raw materials from the supply device 1 to obtain purified cesium vapor. The condensation device 3 is connected to the heating and evaporation device 2 and is suitable for condensing the cesium vapor from the heating and evaporation device 2 and returning it to the heating and evaporation device 2, thereby achieving multiple evaporation and condensation of the cesium raw materials. The condensation device 3 includes a first condenser 320 and a second condenser 330. The first condenser 320 is suitable for condensing a first portion of the cesium vapor from the heating and evaporation device 2 into a first liquid and returning it to the heating and evaporation device 2. The second condenser 330, disposed above the first condenser 320, is suitable for condensing a second portion of the cesium vapor rising from the first condenser 320 into a second liquid, and the second liquid returns to the heating and evaporation device 2 through the first condenser 320.

[0055] In this embodiment, cesium raw material is supplied by the supply device 1 through a pipeline into the heating and evaporation device 2, where it is heated to 300-350°C as needed. The specific temperature is further adjusted by the control system, causing the cesium raw material to evaporate into cesium vapor and rise out of the heating and evaporation device 2. Upon reaching the condenser 3 above the heating and evaporation device 2, it is condensed into liquid cesium. By using the first condenser 320 and the second condenser 330 vertically together, the condensed cesium flows back into the heating and evaporation device 2 through different paths under the influence of gravity. This facilitates the separation of other metal impurities and hydrides from the condensed cesium, thus achieving cesium purification.

[0056] According to some embodiments of the present invention, the supply device 1 is a closed structural unit made of high-temperature resistant metal or alloy material. The metal or alloy material used has good chemical compatibility with cesium metal at high temperatures. Stainless steel can be selected as needed, for example, stainless steel 316. The supply device 1 is used to provide cesium raw material to the heating evaporation device 2.

[0057] According to some embodiments of the present invention, the heating evaporation device 2 is a closed structural unit made of a high-temperature resistant metal material. The metal material used does not react with cesium at high temperatures; for example, stainless steel, preferably stainless steel 316, can be selected as needed. The heating evaporation device 2 can use a heater, an evaporator, a cooling water device, and a control system as needed. The heater is used to provide heat to heat the cesium raw material to 300-350°C, and can be steam-heated, electric-heated, or electrically heated as needed. The evaporator is used to heat the cesium raw material, causing it to move upwards. The evaporator can be a multi-tube, plate, or tank structure to further increase the heat transfer area. The cooling water device provides cooling water B to the heating evaporation device 2 for cooling. Based on the differences in vapor pressure changes with temperature for different substances, the temperature of the heating evaporation device 2 is adjusted through the heater and cooling water circulation, working in conjunction with the evaporator and heater to improve evaporation efficiency. The control system is used to detect and adjust parameters such as temperature, pressure, and flow rate of the heating evaporation device to achieve automated control and operation.

[0058] According to some embodiments of the present invention, the condensing device 3 may be made of 316 stainless steel, which has good chemical compatibility with metallic cesium, as needed. The condensing device 3 may include condenser tubes, cooling medium inlet and outlet, tube bundle, and cooling medium coil. The condenser tubes are heat transfer elements, suitable for receiving incoming cesium vapor and transferring heat to the surrounding cooling medium through thermal conduction, causing the cesium vapor to cool and condense into a liquid state. The cooling medium inlet and outlet are used to guide the cooling medium into and out of the condensing device, realizing heat exchange within the condensing device through the flow of the cooling medium. The tube bundle is suitable for arranging and connecting the condenser tubes in a certain manner, forming the heat transfer structural framework inside the condensing device 3. The tube bundle can be selected as a single row of straight tubes or multiple rows of parallel tubes as needed. The cooling medium coil is used to provide heat transfer between the cooling medium and the condenser tubes, thereby achieving heat transfer and conversion with high efficiency.

[0059] According to some embodiments of the present invention, the condensation device 3 further includes a housing 310, which may be a closed structural unit made of high-temperature resistant metal or alloy material as needed. The metal or alloy material used does not react with cesium metal at high temperatures. Stainless steel may be selected as needed, for example, stainless steel 316.

[0060] Figure 2 It shows Figure 1 An enlarged schematic diagram of section C.

[0061] According to some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the first condenser 320 includes a first column 321 and a first spiral 322. The first column 321 is vertically arranged and has a vertically extending through hole 3211. The first spiral 322 is formed on the periphery of the first column 321 to condense a first portion of cesium vapor into a first liquid, which then flows back into the heating evaporation device 2. The second condenser 330 includes a second column 331, a cooling assembly 332, and a second spiral 333. A closed receiving space is formed inside the second column 331. The cooling assembly 332 is disposed within the receiving space to cool the second column 331. The second spiral 333 is formed on the periphery of the second column 331 to condense a second portion of cesium vapor into a second liquid, which flows back into the heating evaporation device 2 through the through hole 3211 of the first column 321.

[0062] In this embodiment, when the heated and evaporated cesium vapor passes through the first condenser 320, a first portion is condensed and flows back into the heating and evaporation device 2 through the first spiral 322. The cesium vapor that is not condensed in the first condenser 320 enters the second condenser 330 and is further condensed by the cooling effect of the cooling component 332. Then, by gravity, it flows back into the heating and evaporation device 2 through the through hole 3211 of the first column 321. Since the return paths of the first liquid and the second liquid are different, the second liquid flows back into the heating and evaporation device 2 through the through hole 3211, keeping its path unobstructed during the dripping process. This increases the space for separating the condensed cesium from other impurities, thereby facilitating the removal of impurities.

[0063] According to some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the lower end of the second column 331 forms a tapered cone 3311 that tapers downwards. The cone 3311 is aligned with the through hole 3211, allowing the second liquid to collect in the cone 3311 and drip into the through hole 3211. The cone 3311 allows the condensed cesium to collect at the lower end face of the second column 331, causing it to fall under gravity, pass through the through hole 3211 of the first condenser 320, and then return to the heating and evaporating device 2.

[0064] According to some embodiments of the present invention, the cooling assembly 332 includes a cooling pipe 3321 extending into the receiving space of the second column 331. The upper end of the cooling pipe 3321 has an inlet for inputting a cooling medium, and the upper part of the receiving space has an outlet for outputting a cooling medium. This allows the interior of the cooling pipe 3321, the bottom end of the cooling pipe 3321, and the gap between the cooling pipe 3321 and the inner wall of the second column 331 to form a flow path for the cooling medium. The cooling medium flows through the flow path in the second column 331, thereby condensing the cesium vapor rising from the first condenser 320. The condensed cesium then converges from the second spiral 333 to the cone 3311 at the lower part of the second column 331 and drips into the through hole 3211 of the first column 321, and further flows to the heating evaporation device 2. The condensed cesium can be evaporated again or output to the outside and can be used as a purified cesium product for later use.

[0065] like Figure 2 As shown, oil coolant can be selected as needed. The oil coolant is introduced through the inlet of the cooling medium, flows into the bottom of the cooling pipe 3321 under gravity, and then flows back from both sides to the outlet of the cooling medium at the top of the receiving space for discharge. This achieves control over the external temperature distribution of the second condenser 330. Through repeated distillation processes, hydrides with higher vapor pressure are decomposed during distillation, which is beneficial for further separation from condensed cesium.

[0066] According to some embodiments of the present invention, a heating device (not shown in the figure) is provided on the outside of the condensing device 3. The heating device is configured to heat the condensing device 3 to prevent the cesium raw material inside the condensing device 3 from condensing. Although at a relatively high temperature, since the falling condensed cesium does not converge, some of the condensed cesium is prevented from condensing on the inner wall of the shell 310. Therefore, by setting up the heating device, the liquid cesium is ensured to fall back into the heating evaporation device 2 after the gas-liquid phase conversion, thereby reducing the loss of liquid cesium and reducing contamination of the device.

[0067] According to some embodiments of the present invention, the purification system further includes a vacuum device 4 and an inert gas device 5. The vacuum device 4 is connected to the supply device 1, the heating evaporation device 2, and the condensation device 3, and is configured to evacuate the supply device 1, the heating evaporation device 2, and the condensation device 3. The inert gas device 5 is connected to the supply device 1, the heating evaporation device 2, and the condensation device 3, and is configured to introduce inert gas into the supply device 1, the heating evaporation device 2, and the condensation device 3. The vacuum device 4 can be configured as a combination of high and low pressure pumps as needed, including an oil-free composite molecular pump 410 and a mechanical pump 420. By combining the oil-free composite molecular pump 410 and the mechanical pump 420, different vacuum levels can be set in the purification system. The vacuum device 4 removes gaseous impurities generated in the purification system, including non-condensable gaseous impurities and hydrogen gas released from hydrides with higher vapor pressures. After the heating evaporation device 2 and the condensation device 3 are baked and evacuated by the vacuum device 4, the vacuum level can reach 2.66 × 10⁻⁶. -5 Pa achieves a relatively good vacuum atmosphere. Inert gas, such as argon, can be used. The inert gas device 5 and the vacuum device 4 are respectively located on different branches, and one or more valves can be installed as needed, such as... Figure 1 As shown, the valves are made of metal that can withstand high temperatures of 500℃ and corrosion from the active metal cesium. By opening and / or closing different valves, the supply of inert gas is isolated from the vacuum device 4. Inert gas can also be introduced into different devices of the purification system by opening and / or closing valves in different positions. Since cesium is highly chemically reactive and can oxidize and spontaneously combust in air, and reacts violently with water, it may cause an explosion. Therefore, during secondary disassembly and reassembly of the purification system and other operations that expose the system to air, an inert gas such as high-purity argon can be introduced to prevent contamination of the purification system and ensure vacuum cleanliness and safety.

[0068] According to some embodiments of the present invention, the purification system further includes a cold trap 6, disposed between the upper part of the vacuum device 4 and the condenser 3, adapted to prevent cesium vapor in the upper part of the condenser 3 from entering the vacuum device 4. Cooling oil A can be introduced into the cold trap 6 as needed, so that a small amount of cesium vapor escaping from the condenser 3 is cooled and flows back into the condenser 3, and then falls back into the heating evaporator 2 by gravity.

[0069] According to some embodiments of the present invention, the supply device 1 includes a cesium bubble 110 and an extractor 120. The cesium bubble 110 is suitable for glass-encapsulating cesium raw materials. The extractor 120 is constructed with an elastic shell, and the extractor 120 is provided with a receiving space and a filter screen 130 disposed at the bottom of the receiving space. The cesium bubble 110 is placed in the receiving space of the extractor 120. By squeezing the elastic shell, deformation is generated, the cesium bubble 110 is broken, and the cesium raw material flows out of the extractor 120 through the filter screen 130. The cesium to be purified is encapsulated in a glass bubble. Commercially available cesium typically has a purity of 99.5% or higher. Depending on the specific encapsulation process, it may contain a small amount of gas. The cesium bubble 110 is loaded into the extractor 120. The extractor 120 can be configured as a thin-walled structure made of 316 stainless steel, with a 316 stainless steel filter screen 130 at the bottom inside. Heating components can be installed as needed. Extractor 120 contains cesium bubble 110. Under vacuum sealing, the cesium bubble can be broken by mechanical deformation. Cesium, driven by gravity and heat, passes through filter screen 130, separates from the glass fragments of cesium bubble 110, and flows out of extractor 120. The baking temperature of extractor 120 does not exceed 200°C, and other residual gaseous impurities in cesium bubble 110 are removed by vacuum system.

[0070] According to some embodiments of the present invention, a valve may be provided below the filter screen 130 as needed. After the cesium extraction process is completed, the valve is closed to prevent the outflowing cesium raw material from flowing back into the extractor 120 during the heating process.

[0071] According to some embodiments of the present invention, the supply device 1 further includes a transfer device 140, which is connected to the extractor 120 and is suitable for heating the cesium raw material from the extractor 120 and transferring the cesium raw material to the heating and evaporation device 2. The transfer device 140 is heated and baked by an external heating component while cooling water B is flowing through it, wherein the heating temperature is 250-300°C. The cesium raw material is transferred to the heating and evaporation device 2 by gravity and thermal drive. During the transfer process, the heating and evaporation device 2 is cooled by cooling water B. The second condenser 330 in the condensation device 3 is not supplied with cooling oil A. By controlling the temperature distribution of the condensation device 3 and based on the differences in vapor pressure of different substances with temperature changes, impurities with lower vapor pressures such as Fe, Mg, Ca, Li, Na, K, and Cs₂O are retained in the transfer device 140.

[0072] According to some embodiments of the present invention, a fourth valve 11 is further provided between the supply device 1 and the heating evaporation device 2. The fourth valve 11 is configured to allow cesium feedstock from the transferor 140 to be transported to the heating evaporation device 2. After the transfer is completed, the fourth valve 11 is closed, thereby retaining impurities with lower vapor pressure in the transferor 140 and preventing the repeated introduction of these impurities in subsequent repeated heating evaporation and condensation processes.

[0073] According to some embodiments of the present invention, a collection device 7 is also included, which is connected to the heating evaporation device 2 and is suitable for condensing or heating the purified cesium vapor from the heating evaporation device 2 and collecting the purified cesium. The collection device 7 can be cooled by water or heated by an external heating element (not shown in the figure) as needed. When the collection device 7 is cooled by cooling water B, it can collect further purified cesium; when heated, it can provide the thermionic energy converter with high-purity cesium vapor required for power generation.

[0074] According to some embodiments of the present invention, the purification system of the present invention preferably has a metal structure of 316 stainless steel, which can withstand temperatures of over 500°C and has good compatibility with metallic cesium. It can be baked and degassed under vacuum at a relatively high temperature of 450°C, thereby ensuring the vacuum cleanliness of the purification system.

[0075] According to some embodiments of the present invention, the device further includes: a first valve 8 disposed between the heating evaporation device 2 and the collecting device 7; a second valve 9 disposed between the first valve 8 and the collecting device 7; and a third valve 10, one end of which is connected between the first valve 8 and the second valve 9, and the other end of which is connected to the inert gas device 5. The first valve 8 allows purified cesium vapor to be output from the heating evaporation device 2, the second valve 9 allows the purified cesium vapor to enter the collecting device 7, and the third valve 10 allows inert gas to be introduced into the heating evaporation device 2, the supply device 1, the collecting device 7, and the connected pipelines. After the heating evaporation and condensation processes are completed, the first valve 8 is opened to allow the purified cesium vapor to flow out of the heating evaporation device 2, and then the second valve 9 is opened to allow the purified cesium vapor to flow into the collecting device 7. When the first valve 8 and the second valve 9 are opened, cooling water B is introduced into the collecting device 7, and the heating evaporation device 2 is heated at 350-370°C. Non-condensable gaseous impurities are further extracted by the vacuum device 4. Simultaneously, the purified cesium vapor gradually condenses in the collecting device 7, and impurities with lower vapor pressures precipitate and are separated in the heating evaporation device 2. Further purified cesium is obtained in the collecting device 7. After collection, the first valve 8 and the second valve 9 are closed. In the relevant experiments of this invention, the purity of the cesium collected in the collecting device 7 can reach over 99.99%, which meets the high purity requirements of metallic cesium for the thermionic energy converter.

[0076] According to some embodiments of the present invention, a delivery conduit 12 is further included, configured to deliver purified cesium from the collection device 7 to the closed electrode chamber 13 of the thermionic energy converter. This provides high-purity cesium vapor to the electrode chamber 13 of the thermionic energy converter for utilization, further ensuring the thermoelectric conversion performance of the thermionic energy converter.

[0077] According to some embodiments of the present invention, the purification method for metallic cesium mainly includes:

[0078] Cesium feedstock is extracted by heating in a vacuum environment at a heating temperature of 100–200°C.

[0079] In a vacuum environment, cesium raw materials are heated and transported at a heating temperature of 100–300°C.

[0080] In a vacuum environment, cesium raw material is repeatedly heated, evaporated, and condensed at a heating temperature of 300–350°C to obtain purified cesium.

[0081] Purified cesium was collected and processed under vacuum conditions and heating at 350–370°C.

[0082] According to some embodiments of the present invention, the conditions for heating evaporation and condensation are: at 2.6 × 10 -5 Under a vacuum of Pa, heating, evaporation, and condensation are performed to remove cesium hydrides with high vapor pressure and gaseous impurities such as hydrogen released at high temperatures.

[0083] In summary, the cesium purification system provided by this invention utilizes a multi-step vacuum purification process of "extraction-transfer-in-situ distillation-collection" to ensure the cesium raw material flows directionally between the extractor, transferor, heating evaporator, condenser, and collection device. The purified cesium is then collected and utilized in the collection device 7. Non-condensable gases, oxides, hydrides, Li, Na, Fe, Mg, Ca, and other impurities originating from the cesium bubble 110 are effectively removed, and silicon contamination is reasonably avoided. The purified cesium purity can reach 99.99% or higher. For the application of cesium vapor in thermionic energy converters, the contents of critical impurities such as H, O, Ca, and Si in cesium are strictly controlled, thereby ensuring the thermoelectric conversion performance of thermionic energy converters.

[0084] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for purifying metallic cesium, comprising: a supply device adapted to supply a cesium raw material; a heating and evaporation device adapted to heat and evaporate the cesium raw material from the supply device to obtain a purified cesium vapor; and a condensing device in communication with the heating and evaporation device, adapted to condense the cesium vapor from the heating and evaporation device and return it to the heating and evaporation device to achieve multiple evaporation and condensation of the cesium raw material; wherein the condensing device comprises: a first condenser adapted to condense a first portion of the cesium vapor from the heating and evaporation device into a first liquid and return it to the heating and evaporation device; and a second condenser disposed above the first condenser, adapted to condense a second portion of the cesium vapor rising from the first condenser into a second liquid, the second liquid returning to the heating and evaporation device through the first condenser.

2. The system of claim 1, wherein: the first condenser comprises: a first column disposed vertically and having a vertically extending through hole; and a first spiral formed on the periphery of the first column, adapted to condense the first portion of the cesium vapor into the first liquid and return it to the heating and evaporation device; the second condenser comprises: a second column having a closed containing space formed inside; a cooling assembly disposed in the containing space to cool the second column; and a second spiral formed on the periphery of the second column, adapted to condense the second portion of the cesium vapor into the second liquid, the second liquid returning to the heating and evaporation device through the through hole of the first column. a lower end of the second column forms a tapered cone that is aligned with the through hole, so that the second liquid converges to the tapered cone and drips into the through hole.

3. The purification system of claim 2, wherein, the cooling assembly comprises a cooling tube extending into the containing space of the second column, an upper end of the cooling tube having an inlet adapted to input a cooling medium, an upper portion of the containing space having an outlet adapted to output the cooling medium, so that the inside of the cooling tube, the bottom end of the cooling tube and the gap between the cooling tube and the inner wall of the second column form a flow path of the cooling medium.

4. The purification system of claim 2, wherein, an external portion of the condensing device is provided with a heating device configured to heat the condensing device to avoid condensation of the cesium raw material in the condensing device.

5. The purification system of any one of claims 1-4, wherein, 6. The system of any one of claims 1-4, further comprising: a vacuum device connected to the supply device, the heating and evaporation device and the condensing device, configured to vacuumize the supply device, the heating and evaporation device and the condensing device; and an inert gas device connected to the supply device, the heating and evaporation device and the condensing device, configured to introduce inert gas into the supply device, the heating and evaporation device and the condensing device.

7. The system of claim 6, further comprising: a cold trap disposed between the vacuum device and an upper portion of the condensing device, adapted to prevent the cesium vapor in the upper portion of the condensing device from entering the vacuum device. ​ 8. The purification system of any one of claims 1-4, wherein, The supply device comprises: a cesium bubble adapted to encapsulate a cesium raw material; an extractor configured to have an elastic shell, the extractor being provided with a containing space and a filter screen arranged at the bottom of the containing space, the cesium bubble being arranged in the containing space of the extractor, and the cesium raw material is extracted from the extractor by extruding the elastic shell to generate deformation and break the cesium bubble, and then the cesium raw material flows out of the extractor through the filter screen.

9. The purification system of claim 8, wherein, The supply device further comprises: a transfer device in communication with the extractor, and adapted to heat the cesium raw material from the extractor and transfer the cesium raw material to the heating and evaporation device.

10. The purification system of claim 6, further comprising: a collection device in communication with the heating and evaporation device, and adapted to condense or heat the purified cesium vapor from the heating and evaporation device and collect the purified cesium.

11. The purification system of claim 10, further comprising: a first valve arranged between the heating and evaporation device and the collection device; a second valve arranged between the first valve and the collection device; and a third valve, one end of the third valve being connected between the first valve and the second valve, and the other end being in communication with the inert gas device; wherein the first valve allows the purified cesium vapor to be output from the heating and evaporation device, the second valve allows the purified cesium vapor to enter the collection device, and the third valve allows the inert gas to be introduced into the heating and evaporation device, the supply device, and the collection device.

12. The purification system of claim 11, further comprising: a delivery pipeline configured to deliver the purified cesium from the collection device to an electrode chamber of a sealed thermionic energy converter.

13. The purification system of claim 9, further comprising: a fourth valve arranged between the supply device and the heating and evaporation device, the fourth valve being configured to allow the cesium raw material from the transfer device to be delivered to the heating and evaporation device. ​

Images