A method for removing rubidium as an impurity from metallic cesium

Abstract

The present invention discloses a method for removing rubidium as an impurity from cesium metal. The method comprises the following steps: mixing a cesium compound with a reducing agent and silicon dioxide, thoroughly drying the mixture, and then placing the mixture in a reduction device for high-temperature reduction under vacuum conditions to obtain cesium metal vapor from which the rubidium impurity has been removed; and cooling the cesium vapor to obtain cesium metal from which the rubidium impurity has been removed. The present invention provides a simple, low-cost, and efficient method for removing the rubidium impurity from cesium metal, thereby facilitating the production of higher-purity cesium metal and promoting the development of high-end cesium metal clocks and precision photoelectric tube technologies.

Description

Technical Field

[0001] The present invention relates to the technical field of purification of metallic cesium, in particular to a method for removing rubidium as an impurity from metallic cesium. Background Art

[0002] Atomic clocks are key technologies for astronomical research, rocket launch and recovery, and high-precision laser development. They directly determine the depth of astronomical research and the critical guarantee for rocket launches. Ground-based ranging is particularly important during aircraft takeoff and landing, ensuring safety. They also directly determine reactor safety in controlling reactor reaction intensity.

[0003] Cesium metal is a room-temperature liquid metal used in the manufacture of phototubes and atomic clocks. Cesium metal purification technology is key to the development of high-end cesium metal clocks and precision phototubes. Currently, cesium metal is primarily prepared by using cesium compounds as raw materials, followed by a high-temperature reduction reaction in the presence of a reducing agent. Removal of the rubidium impurity during the preparation of cesium metal is crucial for achieving high purity. This is because cesium metal and rubidium are associated metals, and cross-doping between cesium and rubidium is inevitable during the preparation process. Furthermore, cesium and rubidium have similar atomic radii and properties, making separation challenging. To meet the demands of high-end and precision manufacturing, a simpler method is needed to remove the rubidium impurity from cesium metal, thereby achieving higher purity. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a method for removing rubidium as an impurity in metallic cesium.

[0005] The present invention provides a method for removing rubidium as an impurity from metallic cesium, comprising the following steps: mixing a cesium compound with a reducing agent and silicon dioxide, fully drying the mixture, and then reducing the mixture at high temperature under vacuum conditions to obtain metallic cesium vapor from which the rubidium impurity has been removed; and cooling the cesium vapor to obtain metallic cesium from which the rubidium impurity has been removed.

[0006] Preferably, the cesium compound is at least one of cesium carbonate, cesium hydroxide, cesium bicarbonate, cesium sulfate, cesium nitrate, cesium chloride, cesium iodide, cesium bromide, and cesium acetate.

[0007] Preferably, the reducing agent is metallic calcium.

[0008] Preferably, the mass ratio of the cesium compound to the reducing agent and silicon dioxide is (324-326):(96-100):(0.1-0.25).

[0009] Preferably, the silicon dioxide has a purity of 99.9% and a particle size of 40-45 μm.

[0010] Preferably, the drying temperature is 105-120° C. and the drying time is 12-16 hours.

[0011] Preferably, the high-temperature reduction is carried out at a temperature of 680-700° C. and for a time of 2-2.5 h.

[0012] In the present invention, high-temperature reduction under vacuum conditions is carried out in a reduction device, and the specific method includes: evacuating until the vacuum pressure in the reduction device is 300-380 Pa, then heating to 680-700° C., and keeping the temperature for reaction for 2-2.5 hours.

[0013] In the present invention, before the high-temperature reduction under vacuum conditions, the process further includes: removing air from the reduction device by alternately evacuating the device and introducing a high-purity inert gas. The specific method may be, for example, placing a container containing the cesium compound, the reducing agent, and the silicon dioxide into the reduction device, first evacuating the device for 30 minutes to a vacuum degree of -0.086 MPa, then stopping the evacuation, introducing high-purity argon gas for 13-15 minutes, stopping the introduction of argon gas, evacuating the device again for 10 minutes, then stopping the evacuation, and introducing high-purity argon gas again for 13-15 minutes.

[0014] The beneficial effects of the present invention are as follows:

[0015] During the reduction of a cesium compound to cesium metal, the present invention incorporates silicon dioxide as an oxidant, causing the reduced metallic rubidium to preferentially react with the silicon dioxide to form solid impurities. This prevents the rubidium element from distilling during the subsequent distillation process, forming vapor that is doped into the cesium metal vapor, thereby achieving the purpose of separating and removing the rubidium impurity from the cesium metal. The method of the present invention can simply, cost-effectively, and efficiently remove the rubidium impurity from cesium metal, thereby obtaining higher-purity cesium metal and promoting the development of high-end metal cesium clocks and precision photoelectric tube technologies. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is described in detail below through specific embodiments.

[0017] Example 1

[0018] 326 g of cesium carbonate with a purity of 99.9% (the rubidium content in the cesium carbonate is 0.05% by mass) is placed in a sintered dish with 100 g of metallic calcium particles and 0.1 g of silicon dioxide with a purity of 99.9% and a particle size of 40-45 μm. The mixture is mixed evenly and dried at 115° C. for 15 h. The mixture is then placed in a reduction device and evacuated for 30 min to a vacuum degree of -0.086 MPa. The evacuation is then stopped and high-purity argon is introduced for 15 min. The introduction of argon is stopped and the mixture is evacuated again for 10 min. The evacuation is then stopped and high-purity argon is introduced again for 15 min. The introduction of argon is stopped and the mixture is evacuated until the vacuum pressure in the reduction device reaches 300-380 Pa. The mixture is then heated to 690° C. and kept warm for 2 h to obtain metallic cesium vapor from which the rubidium impurity has been removed. The cesium vapor is cooled to obtain metallic cesium from which the rubidium impurity has been removed.

[0019] After testing, the content of rubidium in the metallic cesium obtained above was 5 / 10 by mass. 7 .

[0020] Comparative Example 1

[0021] 326 g of cesium carbonate with a purity of 99.9% (the rubidium content in cesium carbonate is 0.051% by mass) and 100 g of metallic calcium particles are placed in a sintered dish, mixed evenly, dried at 115° C. for 15 h, and then placed in a reduction device. The mixture is first evacuated for 30 min to a vacuum degree of -0.086 MPa, and then the evacuation is stopped. High-purity argon is introduced for 15 min. The introduction of argon is stopped, and the mixture is evacuated again for 10 min. The evacuation is then stopped, and high-purity argon is introduced again for 15 min. The introduction of argon is stopped again, and the evacuation is carried out until the vacuum pressure in the reduction device is 300-380 Pa. The mixture is then heated to 690° C. and kept warm for 2 h to obtain metallic cesium vapor. The cesium vapor is cooled to obtain metallic cesium.

[0022] After testing, the rubidium content in the metallic cesium obtained above was 0.046% by mass.

[0023] Example 2

[0024] 325 g of cesium carbonate with a purity of 99.9% (the rubidium content in cesium carbonate is 0.038% by mass) is placed in a sintered dish with 98 g of metallic calcium particles and 0.2 g of silicon dioxide with a purity of 99.9% and a particle size of 40-45 μm. The mixture is mixed evenly and dried at 105° C. for 12 h. The mixture is then placed in a reduction device and evacuated for 30 min to a vacuum degree of -0.086 MPa. The evacuation is then stopped and high-purity argon is introduced for 15 min. The introduction of argon is stopped and the mixture is evacuated again for 10 min. The evacuation is then stopped and high-purity argon is introduced again for 15 min. The introduction of argon is stopped and the mixture is evacuated until the vacuum pressure in the reduction device is 300-380 Pa. The mixture is then heated to 680° C. and kept warm for 2 h to obtain metallic cesium vapor from which the rubidium impurity has been removed. The cesium vapor is cooled to obtain metallic cesium from which the rubidium impurity has been removed.

[0025] After testing, the content of rubidium in the metallic cesium obtained above was 4 / 10 by mass. 7 .

[0026] Comparative Example 2

[0027] 325 g of cesium carbonate with a purity of 99.9% (the rubidium content in cesium carbonate is 0.038% by mass) and 98 g of metallic calcium particles are placed in a sintered dish, mixed evenly, dried at 105° C. for 12 h, and then placed in a reduction device. The mixture is first evacuated for 30 min to a vacuum degree of -0.086 MPa, and then the evacuation is stopped. High-purity argon is introduced for 15 min. The introduction of argon is stopped, and the mixture is evacuated again for 10 min. The evacuation is then stopped, and high-purity argon is introduced again for 15 min. The introduction of argon is stopped again, and the evacuation is continued until the vacuum pressure in the reduction device is 300-380 Pa. The mixture is then heated to 680° C. and kept warm for 2 h to obtain metallic cesium vapor. The cesium vapor is cooled to obtain metallic cesium.

[0028] After testing, the rubidium content in the metallic cesium obtained above was 0.032% by mass.

[0029] Example 3

[0030] 324 g of cesium carbonate with a purity of 99.9% (the rubidium content in cesium carbonate is 0.034% by mass) is placed in a sintered dish with 96 g of metallic calcium particles and 0.25 g of silicon dioxide with a purity of 99.9% and a particle size of 40-45 μm. The mixture is mixed evenly and dried at 120° C. for 16 h. The mixture is then placed in a reduction device and evacuated for 30 min to a vacuum degree of -0.086 MPa. The evacuation is then stopped and high-purity argon is introduced for 15 min. The introduction of argon is stopped and the evacuation is repeated for 10 min. The evacuation is then stopped and high-purity argon is introduced again for 15 min. The introduction of argon is stopped and the evacuation is repeated until the vacuum pressure in the reduction device is 300-380 Pa. The mixture is then heated to 700° C. and kept warm for 2.5 h to obtain metallic cesium vapor from which the rubidium impurity has been removed. The cesium vapor is cooled to obtain metallic cesium from which the rubidium impurity has been removed.

[0031] After testing, the content of rubidium in the metallic cesium obtained above was 4 / 10 by mass. 7 .

[0032] Comparative Example 3

[0033] 324 g of cesium carbonate with a purity of 99.9% (the rubidium content in cesium carbonate is 0.034% by mass) and 96 g of metallic calcium particles are placed in a sintered dish, mixed evenly, dried at 120° C. for 16 h, and then placed in a reduction device. The mixture is first evacuated for 30 min to a vacuum degree of -0.086 MPa, and then the evacuation is stopped. High-purity argon is introduced for 15 min. The introduction of argon is stopped, and the mixture is evacuated again for 10 min. The evacuation is then stopped, and high-purity argon is introduced again for 15 min. The introduction of argon is stopped again, and the evacuation is carried out until the vacuum pressure in the reduction device is 300-380 Pa. The mixture is then heated to 700° C. and kept warm for 2.5 h to obtain metallic cesium vapor. The cesium vapor is cooled to obtain metallic cesium.

[0034] After testing, the rubidium content in the metallic cesium obtained above was 0.030% by mass.

[0035] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for removing rubidium as an impurity from metallic cesium, characterized in that: The method comprises the following steps: mixing a cesium compound with a reducing agent and silicon dioxide, fully drying the mixture, and then reducing the mixture at high temperature under vacuum conditions to obtain metallic cesium vapor from which the impurity rubidium has been removed; and cooling the cesium vapor to obtain metallic cesium from which the impurity rubidium has been removed.

2. The method for removing rubidium as an impurity in metallic cesium according to claim 1, wherein: The cesium compound is at least one of cesium carbonate, cesium hydroxide, cesium bicarbonate, cesium sulfate, cesium nitrate, cesium chloride, cesium iodide, cesium bromide, and cesium acetate.

3. The method for removing rubidium as an impurity in metallic cesium according to claim 1, characterized in that: The reducing agent is metallic calcium.

4. The method for removing rubidium as an impurity from metallic cesium according to claim 1, wherein: The mass ratio of the cesium compound to the reducing agent and silicon dioxide is (324-326):(96-100):(0.1-0.25).

5. The method for removing rubidium as an impurity from metallic cesium according to claim 1, wherein: The purity of the silicon dioxide is 99.9% and the particle size is 40-45 μm.

6. The method for removing rubidium as an impurity in metallic cesium according to claim 1, characterized in that: The drying temperature is 105-120° C. and the drying time is 12-16 hours.

7. The method for removing rubidium as an impurity from metallic cesium according to claim 1, characterized in that: The temperature of the high-temperature reduction is 680-700° C., and the time is 2-2.5 hours.