A preparation device and preparation method for preparing rubidium or cesium by vacuum thermal reduction

Abstract

The present invention relates to a preparation device and a preparation method for preparing rubidium or cesium by vacuum thermal reduction. The preparation device includes a reaction tube, in which an isolation block is arranged. The left side of the isolation block is a metal thermal reduction chamber, and the right side of the isolation block is a metal vapor condensation chamber. A communication channel is arranged between the upper end of the isolation block and the top of the reaction tube. The preparation device further includes a heating device for heating the metal thermal reduction chamber and a temperature adjustment device for adjusting the temperature of the metal vapor condensation chamber. The right end of the reaction tube is detachable and connected with a flange blank, and a ventilation pipe is connected to the flange blank. A pressure measuring element and a ventilation pipe switch valve are arranged on the ventilation pipe. A discharge pipe is arranged at the bottom of the metal vapor condensation chamber, and a discharge pipe switch valve is arranged on the discharge pipe. The present invention provides a preparation device for preparing rubidium or cesium by vacuum thermal reduction with a simple structure, and can also avoid the technical problem that the corresponding valves are prone to failure under high-temperature working conditions.

Description

Technical Field

[0001] The present invention relates to the field of rubidium or cesium preparation, and particularly to a preparation device and a preparation method for preparing rubidium or cesium by vacuum thermal reduction. Background Art

[0002] Both rubidium and cesium are alkali metal elements, with relatively low densities and very active chemical properties, and are extremely easy to oxidize in the air. Metallic rubidium is silver-white, with a melting point of 39.3 °C and a density of 1.53 g / cm 3 , metallic cesium is golden-yellow, with a melting point of 28.5 °C and a density of 1.87 g / cm 3 . The physical properties of these two elements are very special, with strong softness and high ductility, and relatively high electrical and thermal conductivities, and have a significant photoelectric effect. Rubidium and cesium mainly exist in the form of compounds in nature.

[0003] In recent years, rubidium, cesium and their compounds have been widely used in the information industry, nuclear energy, aerospace technology, fluorescent materials, optical crystals, medicine, catalysts, etc. due to their unique properties, and the main application fields are high-tech industries such as biomedicine and electronics manufacturing. With the development of technology and manufacturing, the future demand growth points for rubidium and cesium should mainly focus on fields such as 5G, satellites, and quantum technology.

[0004] At present, the main production methods of metallic rubidium and cesium are electrolysis, thermal decomposition and metallothermic reduction methods, among which the metallothermic reduction method is the simplest and most mainstream method. This method uses a salt containing rubidium or cesium as a raw material, uses a strongly reducing metal (such as lithium, sodium, calcium, magnesium) as a reducing agent, conducts a reduction reaction at high temperature and in an inert atmosphere, and then uses vacuum distillation to transfer rubidium and cesium out of the reaction device in the form of vapor, and the metal vapor is condensed and collected into a container after condensation.

[0005] The existing thermal reduction equipment for metallothermic reduction reaction of rubidium or cesium has a complex structure, and the entire equipment is under high-temperature conditions, with high requirements for the airtightness and safety of components, high costs, and the complex equipment structure will also make it difficult to clean the inside of the equipment.

[0006] The device needs to be carried out under the protection of high-pressure inert gas, or needs to be replaced with inert gas multiple times to displace air before the reaction, and the reaction process is relatively complex and cumbersome, and the preparation efficiency is low.

[0007] When the temperature is too low, metallic rubidium or cesium will solidify into a solid state and it is difficult to transfer inside the device. Therefore, the devices in the prior art need to be provided with multiple heating elements to ensure that the prepared metallic rubidium or cesium is in a liquid state for easy transfer, which will undoubtedly further lead to a more complex equipment structure and a further reduction in the preparation efficiency of thermal reduction. Summary of the Invention

[0008] The object of the present invention is to provide a preparation device for vacuum thermal reduction to prepare rubidium or cesium with a simple structure, and at the same time, it can also avoid the technical problem that the corresponding valves are prone to failure under high-temperature working conditions; another object of the present invention is to provide a preparation method for preparing rubidium or cesium using this preparation device.

[0009] To solve the above technical problems, the technical solution of a preparation device for vacuum thermal reduction to prepare rubidium or cesium in the present invention is as follows:

[0010] A preparation device for vacuum thermal reduction to prepare rubidium or cesium includes a reaction tube with an axis extending in the left-right direction. An isolation block is arranged inside the reaction tube. The inner cavity of the reaction tube on the left side of the isolation block is a metal thermal reduction chamber, and the inner cavity of the reaction tube on the right side of the isolation block is a metal vapor condensation chamber. A communication channel connecting the metal thermal reduction chamber and the metal vapor condensation chamber is arranged between the upper end of the isolation block and the top of the reaction tube. The preparation device further includes a heating device for heating the metal thermal reduction chamber and a temperature adjustment device for adjusting the temperature of the metal vapor condensation chamber. The right end of the reaction tube is detachably connected with a flange blanking plate. A ventilation pipe is connected to the flange blanking plate. A pressure measuring element and a ventilation pipe switch valve are arranged on the ventilation pipe. A discharge pipe is arranged at the bottom of the metal vapor condensation chamber, and a discharge pipe switch valve is arranged on the discharge pipe.

[0011] Further, the isolation block is a wedge-shaped block. The top of the isolation block is an inclined surface that gradually slopes downward from left to right. The discharge pipe is located on the right side of the inclined surface.

[0012] Further, the heating device is located on the periphery of the metal heating reduction chamber. A reaction tube sealing plate is fixed at the left end of the reaction tube. An installation tube with an axis extending in the left-right direction and its right end extending into the metal thermal reduction chamber is fixed on the reaction tube sealing plate. A thermocouple for detecting the temperature of the metal thermal reduction chamber is arranged inside the installation tube.

[0013] Further, the temperature adjustment device includes a fan for blowing air to cool the outer wall of the reaction tube and a heat preservation layer for wrapping the outer periphery of the outer wall of the reaction tube to heat up the metal vapor condensation chamber.

[0014] Further, the preparation device further includes a vacuum pump, an inert gas tank, and a first dryer that can be selectively connected to the ventilation pipe as needed.

[0015] Further, the preparation device further includes a storage container and a second dryer that can be selectively connected to the discharge pipe as needed.

[0016] The technical solution of the preparation method in the present invention is:

[0017] This method includes the following steps:

[0018] Step 1: Open the flange blind plate, and feed the dry rubidium salt or cesium salt mixed with a reducing agent into the metal thermal reduction chamber from right to left through the communication channel above the isolation block.

[0019] Step 2: Close the flange blind plate, close the drain pipe switch valve, open the vent pipe switch valve, connect the vent pipe to a vacuum pump, and detect the sealing performance of the reaction tube by evacuating the reaction tube.

[0020] Step 3: Use the vacuum pump to pump the pressure in the reaction tube below 1 Pa, close the vent pipe switch valve, heat the metal thermal reduction chamber with a heating device, heat the outside of the metal thermal reduction chamber to 720 - 830 °C within 60 - 90 minutes, and maintain this temperature. The heat conducted from the metal thermal reduction chamber is dissipated into the air through the wall of the metal vapor condensation chamber. Keep the temperature of the corresponding wall of the metal vapor condensation chamber at 40 - 90 °C through a temperature regulating device.

[0021] Step 4: When the internal temperature of the metal thermal reduction chamber reaches 720 - 830 °C, start calculating the reaction time. React for 90 - 150 minutes, stop heating the metal thermal reduction chamber, and let the preparation device cool naturally.

[0022] Step 5: When the internal temperature of the metal thermal reduction chamber drops to 80 - 90 °C, close the vacuum pump and the vent pipe switch valve, connect the vent pipe to an inert gas tank, open the vent pipe switch valve, and the inert gas tank injects inert gas with a purity of not less than 99.9% into the reaction tube. The pressure in the reaction tube is 105 - 115 kPa.

[0023] Step 6: Close the vent pipe switch valve. After the heat balance in the reaction tube, open the drain pipe switch valve, and introduce the rubidium or cesium in the metal vapor condensation chamber into the storage container connected to the drain pipe through the drain pipe. Then close the drain pipe switch valve.

[0024] Step 7: After the reaction tube cools to room temperature, connect a first dryer to the vent pipe and a second dryer to the drain pipe. The vent pipe communicates with the atmosphere through the first dryer, and the drain pipe communicates with the atmosphere through the second dryer. Open the vent pipe switch valve and the drain pipe switch valve. Air enters the reaction tube through the vent pipe and the drain pipe to oxidize the residual rubidium or cesium in the reaction tube. After 48 - 72 hours, open the flange blind plate and clean the inside of the reaction tube.

[0025] The beneficial effects of the present invention are as follows: a reaction tube is used as a basic reaction container in the present invention, a heating device heats the metal thermal reduction chamber on the left, and the gaseous metal moves through the connecting channel to the metal vapor condensation chamber on the right to condense into liquid for easy recovery. The entire device has a simple structure, one side of the metal vapor condensation chamber belongs to the low-temperature side, the discharge pipe switch valve, the vent pipe switch valve, the pressure measuring element, and the flange plug are all arranged on the low-temperature side, the components are not easily damaged and fail, the entire device has a simple structure, and the cost is low.

[0026] Furthermore, to address the problem that metallic rubidium or cesium will solidify into a solid state and become difficult to transfer when the temperature is too low, in the present invention, at a suitable temperature, an inert gas is introduced into the reaction tube. After the inert gas is introduced, the thermal convection of the gas is used to remove the residual heat of the reactants and the prepared rubidium or cesium metal is heated again (when the container is in a vacuum state, the thermal convection is weak, and the thermal convection will be significantly enhanced after the gas is introduced) to transfer the rubidium or cesium without the need for an additional heating device, thereby ensuring that the rubidium or cesium is successfully collected. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present disclosure are shown in an illustrative and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0028] Figure 1 This is a schematic structural diagram of an embodiment of a device for preparing rubidium or cesium by vacuum thermal reduction in the present invention;

[0029] Explanation of the accompanying symbols: 1. Metal thermal reduction chamber; 2. Metal vapor condensation chamber; 3. Flange plug; 4. Isolation block; 5. Vent pipe; 6. Discharge pipe; 7. Vent pipe switch valve; 8. Discharge pipe switch valve; 9. Mounting pipe; 10. Heating device; 11. Vacuum pressure gauge; 12. Inclined surface; 13. Connecting channel. DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0031] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs. The terms used in the specification of this invention are only for the purpose of describing specific embodiments and are not intended to limit the invention.

[0032] An embodiment of a preparation device for preparing rubidium or cesium by vacuum thermal reduction in the present invention is as Figure 1 shown: It includes a reaction tube 14 whose axis extends in the left - right direction and is horizontally arranged during use. The reaction tube 14 is a seamless stainless - steel tube. A reaction - tube sealing plate is fixed at the left end of the reaction tube, and a flange interface is provided at the right end of the reaction tube. A flange plug 3 is detachably connected to the flange interface through bolts.

[0033] An installation tube 9 whose axis extends in the left - right direction and whose right end extends into the metal thermal reduction chamber is fixed on the reaction - tube sealing plate. An isolation block 4 is arranged in the inner cavity of the reaction tube. The inner cavity of the reaction tube between the left side of the isolation block 4 and the reaction - tube sealing plate is the metal thermal reduction chamber 1, and the inner cavity of the reaction tube between the right side of the isolation block and the flange interface is the metal - vapor condensation chamber 2. A communication channel 13 connecting the metal thermal reduction chamber and the metal - vapor condensation chamber is provided between the upper end of the isolation block and the top of the reaction tube. During use, gaseous rubidium or cesium can move from the metal thermal reduction chamber to the metal - vapor condensation chamber from left to right through the communication channel.

[0034] In this embodiment, the isolation block 4 is a wedge - shaped block. The top of the isolation block is an inclined surface 12 that gradually slopes downward from left to right. The inclined - surface structure is conducive to the right - ward flow of the liquid metal at the top of the isolation block. At the same time, the top left end of the isolation block is a pointed structure, which can reduce the flow resistance when gaseous rubidium or cesium passes through. Preferably, the isolation block can move left and right. When the reaction tube needs to be cleaned, the isolation block can be removed from the right end of the reaction tube, which is convenient for cleaning the reaction tube.

[0035] The preparation device further includes a heating device for heating the metal thermal reduction chamber and a temperature - regulating device for regulating the temperature of the metal - vapor condensation chamber. A ventilation pipe is connected to the flange plug. A pressure - measuring element and a ventilation - pipe switch valve are arranged on the ventilation pipe. The pressure - measuring element is located between the flange plug and the ventilation - pipe switch valve. The pressure - measuring element in this embodiment is a vacuum pressure gauge 11.

[0036] A vertically arranged discharge pipe 6 is provided at the bottom of the metal - vapor condensation chamber. A discharge - pipe switch valve 8 is arranged on the discharge pipe 6. The discharge pipe 6 is located on the right side of the inclined surface. A thermocouple for detecting the temperature of the metal thermal reduction chamber is arranged in the installation tube 9. Both the discharge - pipe switch valve and the ventilation - pipe switch valve are ball valves.

[0037] The heating device 10 is arranged on the periphery of the left end of the reaction tube. The temperature regulating device includes a fan for blowing air to cool the outer wall of the reaction tube and a heat preservation layer for wrapping the outer periphery of the outer wall of the reaction tube to heat up the metal vapor condensation chamber.

[0038] In this embodiment, the preparation device further includes a vacuum pump, an inert gas tank and a first dryer selectively connected to the ventilation pipe as required. The inert gas tank stores an inert gas with a purity of not less than 99.9%. The inert gas can be helium, argon, etc. The preparation device further includes a storage container and a second dryer selectively connected to the ventilation pipe as required.

[0039] In this embodiment, the reaction tube, the ventilation pipe, the flange blanking plate, the discharge pipe and the installation pipe are all made of SUS316 stainless steel. The process of using this preparation device to prepare rubidium or cesium metal is as follows:

[0040] First step: Open the flange blanking plate, and feed the dry rubidium salt or cesium salt mixed with the reducing agent from right to left into the metal thermal reduction chamber through the communication channel above the isolation block; specifically, the rubidium salt (rubidium chloride, rubidium carbonate, etc.) or cesium salt (cesium chloride, cesium carbonate, etc.) is dried to constant weight at 105 °C, and then mixed evenly with a reducing agent (calcium metal) 3 to 4 times the chemical dosage required for the reduction reaction.

[0041] Second step: Close the flange blanking plate, close the switch valve of the discharge pipe, open the switch valve of the ventilation pipe, connect the ventilation pipe to the vacuum pump, and detect the sealing performance of the reaction tube by evacuating the reaction tube; the specific process of the sealing performance detection is to start the vacuum pump to pump the internal pressure of the reaction tube to below 1 Pa, and keep the vacuum pump running continuously for 5 to 10 minutes, then close the vacuum pump and the switch valve of the ventilation pipe to detect the leak of the reaction tube. After the switch valve of the ventilation pipe is closed for 5 minutes, read the vacuum pressure gauge again. If the internal pressure of the device is lower than 100 Pa, it indicates that the sealing performance of the preparation device meets the standard and the next step can be carried out; if the internal pressure of the preparation device rises above 100 Pa, it indicates that the sealing performance of the device does not meet the standard, and the air tightness of the preparation device (flange interface, switch valve, etc.) needs to be checked, and this operation is repeated.

[0042] Step 3: Use a vacuum pump to pump the pressure in the reaction tube to below 1 Pa, close the on-off valve of the ventilation pipe, heat the metal thermal reduction chamber with a heating device, heat the outside of the metal thermal reduction chamber to 720 - 830 °C within 60 - 90 minutes, and maintain this temperature. The heat conducted from the metal thermal reduction chamber is dissipated into the air through the tube wall of the metal vapor condensation chamber. Use a temperature adjustment device to keep the temperature of the tube wall corresponding to the metal vapor condensation chamber at 40 - 90 °C. The specific adjustment process of the temperature adjustment device is as follows: Since the temperature of the heating device 10 and the change in the ambient temperature will cause the outer surface temperature of the metal vapor condensation chamber to change accordingly. If it is lower than 40 - 90 °C, use a heat-insulating layer composed of heat-insulating cotton to wrap the outer wall of the metal vapor condensation chamber for heat insulation to keep the temperature at 40 - 90 °C. If the outer surface temperature of the metal vapor condensation chamber is higher than 40 - 90 °C, use cold air to blow the outer wall to lower its temperature to 40 - 90 °C.

[0043] Step 4: When the internal temperature of the metal thermal reduction chamber reaches 720 - 830 °C, start calculating the reaction time, react for 90 - 150 minutes, stop heating the metal thermal reduction chamber, and let the preparation device cool naturally.

[0044] Step 5: When the internal temperature of the metal thermal reduction chamber drops to 80 - 90 °C, close the vacuum pump and the on-off valve of the ventilation pipe, connect the ventilation pipe to the inert gas tank, open the on-off valve of the ventilation pipe, and the inert gas tank injects inert gas with a purity of not less than 99.9% into the reaction tube, and the pressure in the reaction tube is 105 - 115 kPa.

[0045] Step 6: Close the on-off valve of the ventilation pipe. After the heat balance in the reaction tube, open the on-off valve of the discharge pipe, and introduce the rubidium or cesium in the metal vapor condensation chamber into the storage container connected to the discharge pipe through the discharge pipe, and then close the on-off valve of the discharge pipe;

[0046] Step 7: After the reaction tube cools to room temperature, connect a first dryer to the ventilation pipe and a second dryer to the discharge pipe. The ventilation pipe communicates with the atmosphere through the first dryer, and the discharge pipe communicates with the atmosphere through the second dryer. Open the on-off valve of the ventilation pipe and the on-off valve of the discharge pipe. Air enters the reaction tube through the ventilation pipe and the discharge pipe to oxidize the residual rubidium or cesium in the reaction tube. After 48 - 72 hours, open the flange plug to clean the inside of the reaction tube.

[0047] In the present invention, the metal thermal reduction chamber and the metal vapor condensation chamber are located in the same reaction tube, with a simple structure. There is no weld on the reaction tube itself, which can meet the high airtightness requirements. The flange plug, vacuum pressure gauge, on-off valve of the ventilation pipe, and on-off valve of the discharge pipe are at room temperature or a relatively low temperature (below 90 °C), reducing the high-temperature stability requirements of the relevant hardware, thereby reducing the cost. The airtightness and safety of the entire preparation device are relatively high, and the cost is relatively low.

[0048] In the present invention, only one heating device needs to be used. The temperature inside the metal thermal reduction chamber can be accurately detected through a thermocouple, so as to achieve more accurate regulation of the reaction temperature. In the third step, the temperature of the metal vapor condensation chamber is controlled through heat diffusion and heat balance; in the fifth step, after introducing an inert gas into the reaction tube, the prepared rubidium or cesium metal is reheated by the heat convection of the gas (when the inside of the reaction tube is in a vacuum state, the heat convection is weak, and the heat convection will be significantly enhanced after introducing the gas), so that the rubidium metal and cesium metal are transferred to the metal vapor condensation chamber. The device is simple, easy to operate, without the need to additionally set up a heating device or additional heating. The preparation device has a simple structure, good airtightness and simple operation. When preparing metals, there is no need to inject high-pressure inert gas for protection, nor to replace the gas inside the reaction tube multiple times. After leak detection in the second step, only by continuing to keep the vacuum pump running can the conditions required for the vacuum thermal reduction reaction of rubidium and cesium metals be provided.

[0049] Example 1 of the preparation method of the preparation device for preparing rubidium or cesium by vacuum thermal reduction in the present invention

[0050] Both the metal thermal reduction chamber and the metal vapor condensation chamber are 2L, and the heating device adopts a horizontal electric furnace with a power of 2kW.

[0051] Weigh 250 g of rubidium chloride (purity > 99.9%, dried to a constant weight at 105 °C) and 140 g of metallic calcium particles (purity > 99.9%). After mixing evenly, add them into the metal thermal reduction chamber. Connect the preparation device well, and start the vacuum pump to reduce the internal pressure of the reaction tube to below 1 Pa. Stop the vacuum pump for leak detection. The pressure inside the device changes from < 1 Pa to about 80 Pa within 5 minutes, and the airtightness of the device meets the requirements. Start the vacuum pump again to reduce the internal pressure of the device to < 1 Pa. Then turn on the heating device and heat it up to 750 °C in 90 minutes and keep it at a constant temperature. After the temperature indication of the thermocouple inserted into the metal thermal reduction chamber reaches 730 °C, start calculating the reaction time. At the same time, use an infrared temperature gun to measure the temperature of the outer wall of the metal vapor condensation chamber and find that its temperature range is 30 - 50 °C, which is lower than the expected requirement. So wrap it with heat-insulating cotton to increase its temperature range to 45 - 60 °C. After the reaction proceeds for 120 minutes, stop heating. Wait until the temperature of the metal thermal reduction chamber drops to about 80 °C, then fill the reaction tube with high-purity helium gas and adjust the pressure to 110 kPa. After the device reaches thermal equilibrium. Open the ball valve of the discharge pipe switch valve to transfer the rubidium metal in the metal vapor condensation chamber to the storage container connected to the discharge pipe. Close the discharge pipe switch valve and remove the storage container. Connect a dryer filled with anhydrous calcium chloride to the ventilation pipe and the discharge pipe respectively, and connect them to the atmosphere and let it stand for 72 hours. Then open the flange blanking plate. There is a small amount of rubidium oxide, unreacted or reaction-generated chlorides, and excessive metallic calcium (in lumps) inside the reaction tube. Carefully take out the lumps of metallic calcium and rinse the reaction tube with a large amount of water.

[0052] 125 g of metallic rubidium is collected, and the recovery rate of rubidium is 70.7%, and the purity of metallic rubidium > 99.95%.

[0053] Example 2 of the preparation method of the preparation device for preparing rubidium or cesium by vacuum thermal reduction in the present invention:

[0054] Both the metal thermal reduction chamber and the metal vapor condensation chamber are 2 L, and the heating device uses a horizontal electric furnace with a power of 2 kW.

[0055] Weigh 250 g of rubidium carbonate (purity > 99.5%, dried to a constant weight at 105 °C) and 140 g of metallic calcium particles (purity > 99.9%). After mixing them evenly, add them to the metal thermal reduction chamber. Connect the vacuum pump to the ventilation pipe, and start the vacuum pump to reduce the internal pressure of the preparation device to below 1 Pa. Stop the vacuum pump for leak detection. The pressure inside the preparation device changes from <1 Pa to about 70 Pa within 5 minutes, and the airtightness of the preparation device meets the requirements. Start the vacuum pump again to reduce the internal pressure of the preparation device to <1 Pa. Then turn on the heating device, heat it up to 800 °C in 90 minutes, and keep it at a constant temperature. After the temperature reading of the thermocouple inserted into the metal thermal reduction chamber reaches 750 °C, start calculating the reaction time. At the same time, use an infrared temperature gun to measure the temperature of the outer wall of the metal vapor condensation chamber, and find that its temperature range is 45 - 65 °C, without additional control. After the reaction proceeds for 120 minutes, stop heating. Wait until the temperature of the metal thermal reduction chamber drops to about 80 °C, then fill the reaction tube with high-purity helium gas and adjust the pressure to 110 kPa. After the thermal equilibrium in the reaction tube is achieved. Open the drain pipe switch valve to transfer the rubidium metal in the metal vapor condensation chamber to the storage container previously connected to the drain pipe. Close the drain pipe switch valve and remove the storage container. Connect a dryer filled with anhydrous calcium chloride to the ventilation pipe and the drain pipe respectively, and connect them to the atmosphere, and let it stand for 72 hours. Then open the flange plug. There is a small amount of rubidium oxide, unreacted or reaction-generated chlorides, and excessive metallic calcium (lumps) inside the reaction device. Carefully take out the lumps of metallic calcium, and rinse the reaction tube with a large amount of water.

[0056] 142 g of metallic rubidium is collected, the recovery rate of rubidium is 76.7%, and the purity of metallic rubidium > 99.9%.

[0057] Example 3 of the preparation method of the preparation device for preparing rubidium or cesium by vacuum thermal reduction in the present invention:

[0058] Both the metal thermal reduction chamber and the metal vapor condensation chamber are 2 L, and the heating device uses a horizontal electric furnace with a power of 2 kW.

[0059] Weigh 250 g of cesium chloride (purity > 99.5%, dried to a constant weight at 105 °C) and 120 g of metallic calcium particles (purity > 99.9%). After mixing evenly, add them into the metal thermal reduction chamber. Connect the ventilation pipe to the vacuum pump, and start the vacuum pump to reduce the internal pressure of the preparation device to below 1 Pa. Stop the vacuum pump for leak detection. The internal pressure of the preparation device changes from < 1 Pa to about 80 Pa within 5 minutes, and the airtightness of the preparation device meets the requirements. Start the vacuum pump again to reduce the internal pressure of the preparation device to < 1 Pa, and then turn on the heating device. Heat it up to 830 °C in 90 minutes and keep it at a constant temperature. After the temperature reading of the thermocouple inserted into the metal thermal reduction chamber reaches 780 °C, start calculating the reaction time. At the same time, use an infrared temperature gun to measure the temperature of the outer wall of the metal vapor condensation chamber, and find that its temperature range is 65 - 95 °C, which is higher than the expected requirement. Therefore, use a small fan to cool it air-cooledly to reduce its temperature range to 50 - 75 °C. After the reaction proceeds for 120 minutes, stop heating. Wait for the temperature of the metal thermal reduction chamber to drop to about 80 °C, fill the reaction tube with high-purity helium gas, and adjust the pressure to 110 kPa. After the thermal equilibrium in the reaction tube is achieved. Open the drain pipe switch valve to transfer the cesium metal in the metal vapor condensation chamber to the storage container pre-connected to the drain pipe. Close the drain pipe switch valve and remove the storage container. Connect a desiccator filled with anhydrous calcium chloride to the ventilation pipe and the drain pipe respectively, and communicate with the atmosphere. Let it stand for 72 hours. Then open the flange blanking plate. There is a small amount of cesium oxide, unreacted or reaction-generated chlorides and excessive metallic calcium (lumps) inside the reaction device. Carefully take out the metallic calcium lumps and rinse the reaction tube with a large amount of water.

[0060] 142 g of metallic cesium is collected, the recovery rate of cesium is 76.7%, and the purity of metallic cesium is > 99.9%.

[0061] Example 4 of the preparation method of the preparation device for preparing rubidium or cesium by vacuum thermal reduction in the present invention:

[0062] Both the metal thermal reduction chamber and the metal vapor condensation chamber are 2 L, and the heating device uses a horizontal electric furnace with a power of 2 kW.

[0063] Weigh 250 g of cesium carbonate (purity > 99.9%, dried to a constant weight at 105°C) and 120 g of metal calcium particles (purity > 99.9%). After mixing evenly, add them into the metal thermal reduction chamber. Connect the preparation device well, and start the vacuum pump to reduce the internal pressure of the preparation device to below 1 Pa. Stop the vacuum pump for leak detection. The internal pressure of the preparation device changes from <1 Pa to about 70 Pa within 5 minutes, and the airtightness of the preparation device meets the requirements. Start the vacuum pump again to reduce the internal pressure of the preparation device to <1 Pa, and then turn on the heating device. Heat up to 780°C in 90 minutes and keep it at a constant temperature. After the temperature shown by the thermocouple inserted into the metal thermal reduction chamber reaches 750°C, start calculating the reaction time. At the same time, use an infrared temperature gun to measure the temperature of the outer wall of the metal vapor condensation chamber, and its temperature range is 55 - 75°C, without additional control. After the reaction proceeds for 120 minutes, stop heating. Wait for the temperature of the metal thermal reduction chamber to drop to about 80°C, and then fill the reaction tube with high-purity helium gas and adjust the pressure to 110 kPa. After the preparation device reaches thermal equilibrium. Open the drain pipe switch valve to transfer the cesium metal in the metal vapor condensation chamber to the storage container pre-connected to the drain pipe. Close the drain pipe switch valve and remove the storage container. Connect a desiccator filled with anhydrous calcium chloride to the vent pipe and the drain pipe respectively, and connect them to the atmosphere, and let it stand for 72 hours. Then open the flange blanking plate. There is a small amount of cesium oxide, unreacted or reaction-generated chlorides, and excessive metal calcium (blocky) inside the reaction preparation device. Carefully take out the metal calcium block and rinse the reaction tube with a large amount of water.

[0064] 149 g of cesium metal was collected, the recovery rate of cesium was 73.0%, and the purity of cesium metal was > 99.95%.

[0065] In the above description of this specification, unless otherwise clearly specified and limited, terms such as "fix", "install", "connect" or "couple" should be understood in a broad sense. For example, for the term "connect", it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be the internal communication of two components or the interaction relationship between two components. Therefore, unless otherwise clearly limited in this specification, those skilled in the art can understand the specific meaning of the above terms in the present invention according to specific circumstances.

[0066] Based on the above description of this specification, those skilled in the art can also understand the following terms used, such as "upper", "lower", "front", "rear", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "center", "longitudinal", "transverse", "clockwise" or "counterclockwise", etc. The terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings of this specification. It is only for the purpose of facilitating the description of the solution of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operate in the specific orientation. Therefore, the above terms of orientation or positional relationship cannot be understood or interpreted as a limitation to the solution of the present invention.

[0067] In addition, the terms "first" or "second" etc. used in this specification to refer to numbers or ordinals are only for descriptive purposes and cannot be understood as explicitly or implicitly indicating relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this specification, the meaning of "a plurality of" is at least two, such as two, three or more, etc., unless otherwise specifically defined.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A preparation device for preparing rubidium or cesium by vacuum thermal reduction, characterized in that: It includes a reaction tube with its axis extending in the left-right direction. An isolation block is arranged inside the reaction tube. The inner cavity of the reaction tube on the left side of the isolation block is a metal thermal reduction chamber, and the inner cavity of the reaction tube on the right side of the isolation block is a metal vapor condensation chamber. A communication channel connecting the metal thermal reduction chamber and the metal vapor condensation chamber is arranged between the upper end of the isolation block and the top of the reaction tube. The preparation device further includes a heating device for heating the metal thermal reduction chamber and a temperature adjustment device for adjusting the temperature of the metal vapor condensation chamber. The right end of the reaction tube is detachable and connected with a flange blanking plate. A ventilation pipe is connected to the flange blanking plate. A pressure measuring element and a ventilation pipe switch valve are arranged on the ventilation pipe. A discharge pipe is arranged at the bottom of the metal vapor condensation chamber. A discharge pipe switch valve is arranged on the discharge pipe. The isolation block is a wedge-shaped block, and the top of the isolation block is an inclined surface that gradually slopes downward from left to right. The discharge pipe is located on the right side of the inclined surface. The isolation block can move left and right. When the reaction tube needs to be cleaned, the isolation block can be removed from the right end of the reaction tube.

2. The preparation device according to claim 1, characterized in that: The heating device is located on the periphery of the metal heating reduction chamber. A reaction tube sealing plate is fixed at the left end of the reaction tube. An installation tube with its axis extending in the left-right direction and its right end extending into the metal thermal reduction chamber is fixed on the reaction tube sealing plate. A thermocouple for detecting the temperature of the metal thermal reduction chamber is arranged inside the installation tube.

3. The preparation device according to claim 1, characterized in that: The temperature adjustment device includes a fan for blowing air to cool the outer wall of the reaction tube and a heat preservation layer for wrapping the outer periphery of the outer wall of the reaction tube to heat the metal vapor condensation chamber.

4. The preparation device according to any one of claims 1 to 3, characterized in that: The preparation device further includes a vacuum pump, an inert gas tank and a first dryer that can be selected to be connected to the ventilation pipe as needed.

5. The preparation device according to any one of claims 1 to 3, characterized in that: The preparation device further includes a storage container and a second dryer that can be selected to be connected to the discharge pipe as needed.

6. A preparation method using the preparation device according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: First step, open the flange blank, and feed the dry rubidium salt or cesium salt mixed with a reducing agent into the metal thermal reduction chamber from right to left through the communication channel above the isolation block; Second step, close the flange blank, close the drain pipe switch valve, open the vent pipe switch valve, connect the vent pipe to a vacuum pump, and detect the sealing performance of the reaction tube by evacuating the reaction tube; Third step, evacuate the pressure of the reaction tube to below 1 Pa by the vacuum pump, close the vent pipe switch valve, heat the metal thermal reduction chamber by a heating device, heat the outside of the metal thermal reduction chamber to 720 - 830 °C within 60 - 90 minutes and maintain this temperature. The heat conducted from the metal thermal reduction chamber is dissipated into the air through the tube wall of the metal vapor condensation chamber, and the temperature of the corresponding tube wall of the metal vapor condensation chamber is maintained at 40 - 90 °C by a temperature regulating device; Fourth step, when the internal temperature of the metal thermal reduction chamber reaches 720 - 830 °C, start calculating the reaction time, react for 90 - 150 minutes, stop heating the metal thermal reduction chamber, and let the preparation device cool naturally; Fifth step, when the internal temperature of the metal thermal reduction chamber drops to 80 - 90 °C, close the vacuum pump and the vent pipe switch valve, connect the vent pipe to an inert gas tank, open the vent pipe switch valve, and the inert gas tank injects inert gas with a purity of not less than 99.9% into the reaction tube, and the pressure in the reaction tube is 105 - 115 kPa; Sixth step, close the vent pipe switch valve, after the heat balance in the reaction tube, open the drain pipe switch valve, and introduce the rubidium or cesium in the metal vapor condensation chamber into the storage container connected to the drain pipe through the drain pipe, and then close the drain pipe switch valve; Seventh step, after the reaction tube cools to room temperature, connect a first dryer to the vent pipe and a second dryer to the drain pipe. The vent pipe communicates with the atmosphere through the first dryer, and the drain pipe communicates with the atmosphere through the second dryer. Open the vent pipe switch valve and the drain pipe switch valve, air enters the reaction tube through the vent pipe and the drain pipe to oxidize the residual rubidium or cesium in the reaction tube. After 48 - 72 hours, open the flange blank and clean the inside of the reaction tube.

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