CN117025973A - Method for preparing high-purity cesium metal by one-step metallothermic reduction - Google Patents
Method for preparing high-purity cesium metal by one-step metallothermic reduction Download PDFInfo
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- CN117025973A CN117025973A CN202310892310.8A CN202310892310A CN117025973A CN 117025973 A CN117025973 A CN 117025973A CN 202310892310 A CN202310892310 A CN 202310892310A CN 117025973 A CN117025973 A CN 117025973A
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- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 title claims abstract description 123
- 229910052792 caesium Inorganic materials 0.000 title claims abstract description 122
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 78
- 239000002184 metal Substances 0.000 title claims abstract description 78
- 238000000034 method Methods 0.000 title claims abstract description 57
- 230000009467 reduction Effects 0.000 title claims abstract description 54
- 238000006243 chemical reaction Methods 0.000 claims abstract description 117
- AIYUHDOJVYHVIT-UHFFFAOYSA-M caesium chloride Chemical compound [Cl-].[Cs+] AIYUHDOJVYHVIT-UHFFFAOYSA-M 0.000 claims abstract description 64
- 238000010438 heat treatment Methods 0.000 claims abstract description 64
- 239000011261 inert gas Substances 0.000 claims abstract description 37
- 239000011575 calcium Substances 0.000 claims abstract description 33
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 32
- 239000002245 particle Substances 0.000 claims abstract description 27
- 229910001338 liquidmetal Inorganic materials 0.000 claims abstract description 23
- 238000001035 drying Methods 0.000 claims abstract description 22
- 238000009833 condensation Methods 0.000 claims abstract description 21
- 230000005494 condensation Effects 0.000 claims abstract description 21
- 238000011049 filling Methods 0.000 claims abstract description 6
- 238000003756 stirring Methods 0.000 claims abstract description 5
- 238000004321 preservation Methods 0.000 claims description 46
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
- 238000005086 pumping Methods 0.000 claims description 5
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 239000008367 deionised water Substances 0.000 claims description 3
- 229910021641 deionized water Inorganic materials 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 238000001291 vacuum drying Methods 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 238000000746 purification Methods 0.000 abstract description 5
- 238000006722 reduction reaction Methods 0.000 description 36
- 238000004458 analytical method Methods 0.000 description 29
- 238000002386 leaching Methods 0.000 description 15
- 238000005070 sampling Methods 0.000 description 15
- 229910001220 stainless steel Inorganic materials 0.000 description 15
- 239000010935 stainless steel Substances 0.000 description 15
- 239000006228 supernatant Substances 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 238000007789 sealing Methods 0.000 description 13
- 230000008859 change Effects 0.000 description 11
- 238000002360 preparation method Methods 0.000 description 10
- 238000005352 clarification Methods 0.000 description 9
- 238000011084 recovery Methods 0.000 description 7
- 239000000843 powder Substances 0.000 description 6
- 238000004821 distillation Methods 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- FLJPGEWQYJVDPF-UHFFFAOYSA-L caesium sulfate Chemical compound [Cs+].[Cs+].[O-]S([O-])(=O)=O FLJPGEWQYJVDPF-UHFFFAOYSA-L 0.000 description 4
- 239000000428 dust Substances 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000009776 industrial production Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 2
- FJDQFPXHSGXQBY-UHFFFAOYSA-L caesium carbonate Chemical compound [Cs+].[Cs+].[O-]C([O-])=O FJDQFPXHSGXQBY-UHFFFAOYSA-L 0.000 description 2
- 229910000024 caesium carbonate Inorganic materials 0.000 description 2
- 239000001110 calcium chloride Substances 0.000 description 2
- 229910001628 calcium chloride Inorganic materials 0.000 description 2
- AYTVLULEEPNWAX-UHFFFAOYSA-N cesium;azide Chemical compound [Cs+].[N-]=[N+]=[N-] AYTVLULEEPNWAX-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910052701 rubidium Inorganic materials 0.000 description 2
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- -1 Cesium hydride Chemical compound 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 150000001540 azides Chemical class 0.000 description 1
- UUXFWHMUNNXFHD-UHFFFAOYSA-N barium azide Chemical compound [Ba+2].[N-]=[N+]=[N-].[N-]=[N+]=[N-] UUXFWHMUNNXFHD-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 159000000006 cesium salts Chemical class 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000011534 incubation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 230000004792 oxidative damage Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229910001744 pollucite Inorganic materials 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B5/00—General methods of reducing to metals
- C22B5/02—Dry methods smelting of sulfides or formation of mattes
- C22B5/04—Dry methods smelting of sulfides or formation of mattes by aluminium, other metals or silicon
Abstract
The invention provides a method for preparing high-purity cesium metal by one-step metallothermic reduction, which comprises the following steps: s1, adding dry cesium chloride into a reaction zone of a reaction furnace tube which is clean and dry in a vacuum tube type reduction furnace, carrying out low-temperature vacuumizing and drying, opening a furnace door under the condition of filling inert gas, adding calcium particles into the reaction zone of the reaction furnace tube, stirring and compacting, and completing furnace charging operation; s2, carrying out primary heating and vacuumizing on the vacuum tube type reduction furnace with the furnace charging operation completed, raising the furnace temperature to 350 ℃, preserving heat for 1-2 hours, stopping vacuumizing, then carrying out secondary heating, raising the furnace temperature to 650-900 ℃, condensing cesium vapor generated by the reaction in a condensation collecting area of a reaction furnace tube to form liquid metal cesium, and collecting the liquid metal cesium by using a collecting bottle to obtain the high-purity metal cesium. The invention adopts one-step thermal reduction purification to prepare high-purity cesium, simplifies the process, reduces the cost, has high efficiency and simplicity, and is suitable for industrialized production.
Description
Technical Field
The invention belongs to the technical field of nonferrous metal preparation, and particularly relates to a method for preparing high-purity cesium metal by one-step metal thermal reduction.
Background
Cesium was found to be the most active alkali metal in 1806. Cesium has strong chemical activity and excellent photoelectric property, has irreplaceable effects in the special fields of atomic clocks, aerospace measurement and control, ion rocket engines, medicines and the like, and limits the application of cesium due to high price in the fields of magnetohydrodynamic power generation, catalysts, fuel cells and the like. Along with the rapid development of technology, cesium has been applied more and more widely, and the market demand of low-cost and high-quality cesium has to be expanded.
Cesium is present in the crust at an average level of 7g/t and in the ocean at a level of 0.002g/t, mainly in pollucite. The main preparation methods of cesium metal include electrolysis, thermal decomposition and metallothermic reduction. The electrolytic method for preparing the cesium metal has long period, complex collection process and large metal loss, and is not widely applied. Thermal decomposition is a process for preparing small amounts of high purity cesium. Neutralizing cesium carbonate with azide acid or replacing cesium in the aqueous solution of cesium sulfate with barium azide to obtain cesium azide, and heating and dissociating the cesium azide to obtain purer metallic cesium. Cesium hydride can also be thermally decomposed to produce cesium metal.
The metallothermic reduction method is the most convenient and most common method for preparing cesium metal. Cesium salts such as cesium carbonate and cesium sulfate are used as raw materials, and reducing metals such as lithium, sodium, calcium and magnesium are used as reducing agents, so that the metal cesium is prepared by reduction at high temperature. However, the existing related preparation method has the defects of complicated process flow, continuous production and low industrialization degree.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a simple, efficient and suitable method for industrially producing high-purity cesium. The specific invention comprises the following steps:
the invention provides a method for preparing high-purity cesium metal by one-step metallothermic reduction, which comprises the following steps:
s1, adding dry cesium chloride into a reaction zone of a reaction furnace tube which is clean and dry in a vacuum tube type reduction furnace, carrying out low-temperature vacuumizing and drying, opening a furnace door under the condition of filling inert gas, adding calcium particles into the reaction zone of the reaction furnace tube, stirring and compacting, and completing furnace charging operation;
s2, carrying out primary heating and vacuumizing on the vacuum tube type reduction furnace with the furnace charging operation completed, raising the furnace temperature to 350 ℃, preserving heat for 1-2 hours, stopping vacuumizing, then carrying out secondary heating, raising the furnace temperature to 650-900 ℃, condensing cesium vapor generated by the reaction in a condensation collecting area of a reaction furnace tube to form liquid metal cesium, and collecting the liquid metal cesium by using a collecting bottle to obtain the high-purity metal cesium.
Optionally, the hearth of the vacuum tube type reduction furnace is placed at an included angle of 10-15 degrees with the horizontal direction;
the condensation collecting area of the reaction furnace tube is provided with a straight-through pipeline which forms an included angle of 60 degrees with the reaction furnace tube and is used for connecting the collecting bottle.
Optionally, the reaction furnace tube is a straight tube reaction furnace tube, and a condensation collecting area of the reaction furnace tube adopts a heat preservation measure to ensure that the temperature of the condensation collecting area is not lower than 60 ℃.
Optionally, the purity of the cesium chloride is not lower than 99.5%, and the cesium chloride is dried in vacuum in a vacuum oven at 200 ℃ for 24 hours in advance before use;
the purity of the calcium particles is more than 95 percent, and the granularity of the calcium particles is less than 3mm.
Optionally, in step S1, the reaction furnace tube is washed with 3-5% hydrochloric acid and deionized water in sequence before use, and is dried after being washed with ethanol, wherein the drying method is to raise the furnace temperature of the vacuum tube type reduction furnace to 200 ℃, and the reaction furnace tube is kept open for 4-6 hours.
Optionally, in step S1, the duration of the low-temperature vacuuming and drying is 2 hours, and in the process, the pressure in the reaction furnace tube is kept to be not more than 10 -1 Pa, the temperature is 200 ℃.
Optionally, in step S1, the mass ratio of cesium chloride to the calcium particles is (2-4): 1.
optionally, in step S1, the inert gas is argon or nitrogen.
Optionally, in step S2, when the vacuum pumping is stopped, the pressure in the reaction furnace tube is not greater than 10 -3 Pa。
Optionally, after step S2, the method further includes: and closing the valve of the collecting bottle, taking down the collecting bottle, transferring into a glove box, and carrying out hot melting again and split charging.
Compared with the prior art, the invention has the following advantages:
according to the method for preparing the high-purity cesium through the metal thermal reduction in one step, provided by the invention, the flow of preparing the high-purity cesium through the thermal reduction is greatly shortened through optimizing a reaction device and vacuum conditions in the reaction process, the optimized preparation method omits a purification mode of repeated thermal reduction and distillation in the prior art, the high-purity cesium is prepared through one-step thermal reduction purification, the process is simplified, the cost is reduced, and the method is efficient and simple and is suitable for the high-purity cesium preparation method of industrial production.
In addition, the invention adopts a vacuum tube type reduction furnace device to prepare high-purity cesium metal by one step, the hearth is a horizontal cylindrical groove, the reaction furnace tube is arranged in the circular groove of the hearth, and the whole reaction furnace tube is straight-through type and detachable. The connecting pieces such as the vacuumizing pipeline, the inflating pipeline and the like are positioned at the outer end part of the reaction furnace tube, which is exposed out of the furnace body. The design ensures that the installation and operation of the reaction furnace tube are convenient, the cleaning in the hearth is more convenient and safer, the recovery rate and the production efficiency of the cesium metal are improved, and the method is more suitable for continuous industrial production.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 shows a flow chart of a method for preparing high-purity cesium metal by one-step metallothermic reduction provided by an embodiment of the invention;
fig. 2 shows a schematic diagram of an apparatus for preparing high-purity cesium metal according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Any product that is the same as or similar to the present invention, which anyone in the light of the present invention or combines the present invention with other prior art features, falls within the scope of the present invention based on the embodiments of the present invention. And all other embodiments that may be made by those of ordinary skill in the art without undue burden and without departing from the scope of the invention.
Specific experimental steps or conditions are not noted in the examples and may be performed in accordance with the operation or conditions of conventional experimental steps described in the prior art in the field. The reagents used, as well as other instruments, are conventional reagent products available commercially, without the manufacturer's knowledge. Furthermore, the drawings are merely schematic illustrations of embodiments of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus a repetitive description thereof will be omitted. Some of the block diagrams shown in the figures are functional entities and do not necessarily correspond to physically or logically separate entities.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for defining the components, and are merely for convenience in distinguishing the corresponding components, and the terms are not meant to have any special meaning unless otherwise indicated, so that the scope of the present invention is not to be construed as being limited.
In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
Before describing in detail a method for preparing high-purity cesium metal in one step by metallothermic reduction according to the present invention, the following description of the related art is necessary:
in the existing method for preparing high-purity cesium by adopting metal thermal reduction, patent CN108018435A introduces a preparation method of high-purity metal rubidium and cesium, the method adopts thermal reduction under a vacuum atmosphere to prepare high-purity cesium, but the preparation process needs multiple vacuum reduction-distillation, the preparation period is long, the operation process is complex, and the method is not suitable for industrial application; patent CN107164641A describes a method for preparing high-purity cesium, wherein the method adopts inert gas environment to prepare high-purity cesium, the high-purity cesium is obtained by repeated distillation of the metal cesium obtained by thermal reduction, the process is complicated, the cost is high, the inner wall of a pipeline of the used equipment is S-shaped, the structure is complex, the cleaning is difficult, and potential safety hazards exist during use; patent CN105063375a describes a method for preparing high purity metal rubidium and cesium by vacuum thermal reduction. According to the method, crude metal cesium is obtained through metal thermal reduction under a vacuum state, then high-purity cesium is obtained through distillation of the crude metal cesium, the whole process of reduction is vacuumized, the yield of cesium is affected, and the high-purity cesium is prepared through two steps of reduction-distillation, so that the process is complicated.
The invention provides a method for preparing high-purity cesium metal by one-step metal thermal reduction, which has the following specific implementation contents:
the invention provides a method for preparing high-purity cesium metal by one-step metallothermic reduction, and fig. 1 shows a flow chart of the method for preparing high-purity cesium metal by one-step metallothermic reduction, which is provided by the embodiment of the invention, as shown in fig. 1, and comprises the following steps:
s1, adding dry cesium chloride into the bottom of a reaction furnace tube which is clean and dry in a vacuum tube type reduction furnace, carrying out low-temperature vacuumizing and drying, opening a furnace door under the condition of filling inert gas, adding calcium particles into the bottom of the reaction furnace tube, stirring and compacting to finish furnace loading operation;
s2, carrying out primary heating and vacuumizing on the vacuum tube type reduction furnace with the furnace charging operation completed, raising the furnace temperature to 350 ℃, preserving heat for 1-2 hours, stopping vacuumizing, then carrying out secondary heating, raising the furnace temperature to 650-900 ℃, condensing cesium vapor generated by the reaction at the pipe orifice of the reaction furnace pipe to form liquid metal cesium, and collecting the liquid metal cesium by using a collecting bottle to obtain the high-purity metal cesium.
Referring to fig. 2, fig. 2 shows a schematic structural diagram of an apparatus for preparing high-purity cesium metal according to an embodiment of the present invention, wherein the apparatus adopts a vacuum tube type reduction furnace apparatus for performing metal thermal reduction to prepare high-purity cesium metal in one step, and the vacuum tube type reduction furnace apparatus comprises a furnace body 1, a reaction furnace tube 2, a vacuum system 3, a temperature control system 4 and a collection bottle 5. Wherein, the inside of the furnace body 1 is a horizontal cylindrical groove structure, the reaction furnace tube 2 is a straight tube reaction furnace tube (straight-through type), the quick disassembly can be realized, and the continuous production can be realized by changing the reaction furnace tube 2 in the reaction process. The part of the reaction furnace tube 2 placed in the circular groove of the furnace body 1 is a reaction area, and the part of the reaction furnace tube 2 exposed out of the furnace body 1 is a condensation collecting area. The connecting pieces of the vacuum system 3, such as a vacuumizing pipeline, an inflating pipeline and the like, are connected with the exposed end part of the reaction furnace tube 2. The design ensures that the installation and operation of the reaction furnace tube 2 are convenient and safe, improves the recovery rate and the production efficiency of the metal cesium, and is more suitable for continuous industrial production.
Further, the temperature control system 4 for providing a heat source for the furnace body 1 is resistance heating, the temperature is controlled in a sectional manner, the furnace body is arranged on the temperature control system 4 at an included angle of 10-15 degrees in the horizontal direction, cesium vapor is facilitated to ascend, the cesium vapor reaches a condensation collecting area, reactant and impurity are better separated, and a straight-through pipeline at an included angle of 60 degrees with the reaction furnace tube 2 is arranged in the condensation collecting area of the reaction furnace tube 2 and is used for connecting the reaction furnace tube 2 and the collecting bottle 5.
Further, a heat preservation measure is adopted in the condensation collecting area of the reaction furnace tube 2, so that the temperature of cesium vapor in the tube at the tube orifice for condensation to form metal cesium is kept at not lower than 60 ℃, and a fixed heating belt can be adopted in the heat preservation measure to expose the surface of the furnace body part outside the reaction furnace tube, and heating is carried out.
In the specific implementation, the purity of the reaction raw material cesium chloride is not lower than 99.5%, the purity of the cesium chloride is high, the generation of impurity substances can be reduced, and the purity of the cesium chloride is improved, and the cesium chloride is dried in a vacuum oven at 200 ℃ for 24 hours in advance before being used; the purity of the calcium particles is more than 95 percent, and the granularity of the calcium particles is 1-3mm. The granularity of the metal calcium is too large or too small, which is unfavorable for mixing with cesium compounds, and poor material uniformity is easy to cause incomplete reaction, and affects the purity and yield of cesium.
In particular, the invention is proved by a large number of experiments that the vacuumizing has a decisive effect on ensuring the purity of the cesium metal generated by thermal reduction, and in the conventional preparation process, the vacuumizing is continuously performed from the time of adding raw materials into a reaction device so as to avoid the oxidative damage of oxygen and moisture in the air to the generated cesium simple substance and guide the condensation of cesium vapor in the later stage of the reaction. However, as the vacuum pumping can enable part of fine particles to flow along with the pumping force during the reaction, the action can disturb the thermal reduction reaction of the reaction furnace tube, and the collection of cesium vapor under the vacuum pumping condition can lead to the introduction of trace interference impurities into the collected product. In the step S2, the furnace is heated under the condition of vacuumizing, so that the furnace temperature is raised to 350 ℃, the vacuumizing is stopped after the heat preservation is carried out for 1 to 2 hours, and the pressure in the reaction furnace is not more than 10 -3 Pa, stopping vacuumizing, and heating again to 650-900 deg.C, where the pressure and temp. of raw materials in furnace tube are not greater than 10 - 3 Pa), and the generated cesium vapor freely rises to a condensation collecting area of the reaction furnace tube to be condensed. And after stopping vacuumizing, carrying out secondary heating to the reaction temperature, avoiding that the continuous vacuumizing is used for stirring impurity dust of the reaction raw material and then bringing the dust into a condensation collection area, thereby influencing the purity of the generated cesium simple substance and being more beneficial to obtaining high-purity metal cesium.
Preferably, the furnace temperature is raised to 900 ℃ by secondary heating.
In some embodiments, reaction furnace tube 2 is rinsed with 3-5% hydrochloric acid and deionized water in sequence prior to use, and dried after rinsing with ethanol to obtain a clean reaction furnace tube. The drying method is to raise the temperature of the vacuum tube type reducing furnace to 200 ℃, and keep the temperature of the reaction furnace tube open for 4-6 hours.
In some embodiments, in step S1The duration of low-temperature vacuumizing and drying is 2 hours, and in the process, the pressure in the vacuum tube type reduction furnace is kept to be not more than 10 -1 Pa, the temperature is 200 ℃. The mass ratio of cesium chloride to calcium particles is (2-4): 1. the inert gas is argon or nitrogen.
In some embodiments, after step S2, the method further comprises: closing the valve of the collecting bottle, taking down the collecting bottle, transferring into a glove box, and carrying out hot melting and split charging again.
In order to more clearly understand the present invention, a method for preparing high purity cesium metal in one step by metallothermic reduction according to the present invention will be described in detail by the following examples.
The following examples and comparative examples each employ the apparatus structure for preparing high purity metallic cesium shown in FIG. 2 for preparing high purity metallic cesium
Example 1:
60 g cesium chloride (99.5%) is placed in a stainless steel reaction furnace tube, then the tube orifice is sealed and connected with a vacuum system, and the vacuum is pumped to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles are added, and after the cesium chloride which is put in the furnace door is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 680 ℃ under the vacuum state, and the heat preservation is carried out for 120min, so that the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, volume is measured, and supernatant is taken for analysis. The yield of cesium metal was 12.7%.
Comparative example 1:
cesium chloride was dried in a vacuum oven for 24 hours, 60 grams of cesium chloride (99.5%) was placed in a stainless steel reaction furnace tube, and the tube orifice was then sealed andconnecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. After the heat preservation is finished, the power supply is turned off, inert gas is filled into the tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 750 ℃ under the vacuum state, and the heat preservation is carried out for 120min, so that the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. And (3) when the furnace temperature is cooled to room temperature, filling inert gas to normal pressure, opening a furnace cover, fully oxidizing residues in the furnace, leaching with water, clarifying, measuring the volume, and taking supernatant for analysis. The yield of cesium metal was 37.9%.
Comparative example 2:
drying cesium chloride in a vacuum oven for 24 hours, taking 30 g cesium chloride (99.5%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled to enable the pressure in the reaction furnace tube to reach normal pressure, the furnace door is opened, 10 g of calcium particles (99.9%) are added, the furnace door is closed and connected with a vacuum system after the cesium chloride which is put in the furnace door is slightly mixed and compacted. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 850 ℃ under the vacuum state, the heat preservation is carried out for 120min, and the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. And (3) when the furnace temperature is cooled to room temperature, filling inert gas to normal pressure, opening a furnace cover to enable residues in the furnace to be fully oxidized, leaching with water, clarifying, measuring the volume, and taking supernatant for analysis. Recovery of cesium metalThe rate was 87.9%.
Comparative example 3:
drying cesium chloride in a vacuum oven for 24 hours, taking 60 g cesium chloride (99.5%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ under the vacuum state, and the heat preservation is carried out for 120min, so that the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, volume is measured, and supernatant is taken for analysis. The yield of the metal cesium is 96.6%, and the purity of the metal cesium is more than 99.99%.
Example 2:
drying cesium chloride in a vacuum oven for 24 hours, taking 60 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ for heat preservation for 90 minutes in the vacuum state, and the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken out and moved into a glove box, and thenAnd (5) sub-heating and melting for sub-packaging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, volume is measured, and supernatant is taken for analysis. The yield of cesium metal was 96.1%.
Comparative example 4:
drying cesium chloride in a vacuum oven for 24 hours, taking 60 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ for heat preservation for 60 minutes in the vacuum state, and the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. And (3) opening a furnace cover when the furnace temperature is cooled to room temperature, leaching residues in the furnace by water after the residues are fully oxidized, clarifying, measuring the volume, and taking supernatant for analysis. The yield of cesium metal was 85.5%.
Comparative example 5:
drying cesium chloride in a vacuum oven for 24 hours, taking 60 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. After the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ under the vacuum state, the heat preservation is carried out for 120min, and the furnace is used in the whole reaction processThe internal pressure did not change significantly. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, volume is measured, and supernatant is taken for analysis. The yield of the metal cesium is 96.7%, and the purity of the metal cesium is more than 99.999%.
Example 3:
drying cesium chloride in a vacuum oven for 24 hours, taking 70 g cesium chloride (99.5%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Heating to 350 deg.C, maintaining the temperature for 2 hr while maintaining the pressure inside the furnace at not higher than 10% -3 Pa. And (5) after the heat preservation is finished, closing the vacuum pump. Continuously heating to 900 ℃ in the vacuum state in the furnace tube, and preserving heat for 120min. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is added to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, the volume is measured, and the supernatant is taken for analysis. The yield of cesium metal was 92.4%.
Comparative example 6:
drying cesium chloride in a vacuum oven for 24 hours, taking 56 g cesium chloride (99.5%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hrDuring which the pressure in the furnace is kept to be not more than 10 -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, and the temperature is continuously increased to 900 ℃ for 120min under the vacuum state in the furnace tube. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is added to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, the volume is measured, and the supernatant is taken for analysis. The yield of cesium metal was 96.5%.
Example 4:
drying cesium chloride in a vacuum oven for 24 hours, taking 56 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ for heat preservation for 150min under the vacuum state, and the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, volume is measured, and supernatant is taken for analysis. The yield of the metal cesium is 97.6%, and the purity of the metal cesium is more than 99.999%.
Comparative example 7: drying cesium chloride in a vacuum oven for 24 hours, taking 56 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. After the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, and 20 g of calcium is addedPellets (99.9%) were compacted after a slight mixing of the cesium chloride previously placed, the oven door was closed and a vacuum system was connected. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And continuously heating to 900 ℃ and preserving heat for 150min in a vacuumizing state after heat preservation is finished. The cesium metal vapor generated during this period is guided to a condensation site by vacuum suction, condensed into droplets, and then flows into a collection bottle. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the vacuumizing system is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, white powder covers the inner wall of the furnace tube, cesium chloride powder and calcium chloride powder are analyzed, and the fact that fine dust reaches a condensation area along with the suction force in the reaction process is indicated. After the residue in the furnace is fully oxidized, leaching with water, clarifying, measuring the volume, and taking the supernatant for analysis. The yield of cesium metal was 84.6% and the purity of cesium metal was 99.02%.
Comparative example 8:
drying cesium chloride in a vacuum oven for 24 hours, taking 56 g cesium chloride (99.5%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (99.9%) are added, and after the cesium chloride which is put in previously is slightly mixed, the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ for heat preservation for 150min under the vacuum state, and the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. Cooling to room temperature, charging inert gas to normal pressure, opening furnace cover to oxidize residue, leaching with water, clarifying, measuring volume, collecting supernatantAnalysis was performed. The yield of cesium metal was 97.1%.
Example 5:
drying cesium chloride in a vacuum oven for 24 hours, taking 56 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (98%) are added, the cesium chloride which is put in before is slightly mixed and compacted, and the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ for heat preservation for 150min under the vacuum state, and the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, volume is measured, and supernatant is taken for analysis. The yield of cesium metal was 96.5%.
Comparative example 9:
drying cesium chloride in a vacuum oven for 24 hours, taking 56 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (95%) are added, the cesium chloride which is put in before is slightly mixed and compacted, and the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And after the heat preservation is finished, the vacuum pump is turned off, the temperature in the furnace tube is continuously raised to 900 ℃ for heat preservation for 150min under the vacuum state, and the pressure in the furnace tube does not change obviously in the whole reaction process. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated againAnd melting, split charging and sampling analysis are carried out. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, residues in the furnace are fully oxidized, water is used for leaching, clarification, volume is measured, and supernatant is taken for analysis. The yield of the metal cesium is 89.6%, and the purity of the metal cesium is more than 99.99%.
Comparative example 10: drying cesium chloride in a vacuum oven for 24 hours, taking 56 g cesium chloride (99.9%) to be placed in a stainless steel reaction furnace tube, sealing a tube orifice and connecting a vacuum system, and vacuumizing to 10 -1 Pa, heating to 200 ℃, and preserving heat for 2 hours. And after the heat preservation is finished, the power supply is turned off, inert gas is filled into the reaction furnace tube to reach normal pressure, the furnace door is opened, 20 g of calcium particles (95%) are added, the cesium chloride which is put in before is slightly mixed and compacted, and the furnace door is closed and connected with a vacuum system. Vacuumizing, heating to 350 deg.C, and preserving heat for 2 hr while keeping the pressure in the furnace at not more than 10% -3 Pa. And continuously heating to 900 ℃ and preserving heat for 150min in a vacuumizing state after heat preservation is finished. The cesium metal vapor generated during this period is guided to a condensation site by vacuum suction, condensed into droplets, and then flows into a collection bottle. When no liquid metal flows into the collecting bottle, the valve of the collecting bottle is closed, the vacuumizing system is closed, the heating system is closed, the collecting bottle is taken down and moved into a glove box, and the collecting bottle is heated and melted again for split charging and sampling analysis. When the furnace temperature is cooled to room temperature, inert gas is filled to normal pressure, a furnace cover is opened, white powder covers the inner wall of the furnace tube, cesium chloride powder and calcium chloride powder are analyzed, and the fact that fine dust reaches a condensation area along with the suction force in the reaction process is indicated. After the residue in the furnace is fully oxidized, leaching with water, clarifying, measuring the volume, and taking the supernatant for analysis. The yield of cesium metal was 84.1% and the purity of cesium metal was 98.97%.
Recovery rates for the preparation of high purity cesium in each example are shown in table 1 and purity of the prepared high purity cesium is shown in table 2. From the results of tables 1 and 2, it can be seen that:
(1) The yield of liquid cesium increases with increasing reaction temperature and with increasing incubation time.
(2) The amount of metallic calcium is preferably CsCl/Ca weight ratio=2.8-3.
(3) The higher the purity of cesium chloride and metallic calcium, the higher the purity of the prepared metallic cesium.
(4) The absence of vacuum during the high temperature reaction makes it easier to obtain high yields of metallic cesium in high purity (see in particular the experimental results of example 4 and comparative example 7, and of example 5 and comparative example 10).
Table 1 Process for preparing high purity cesium recovery statistics Table in examples
Purity of high purity cesium prepared in Table 2
As shown in the table above, the purity of the high-purity cesium metal prepared in the embodiment reaches 99.999%, and the recovery rate reaches 97%.
In conclusion, the synthetic method has the advantages of fewer procedures, convenience in operation, elimination of complex purification steps, lower production cost, energy conservation, environmental protection and suitability for large-scale popularization, and solves the problems of more recovery method procedures, high purification cost and complex procedures in the prior art.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, one skilled in the art can combine and combine the different embodiments or examples described in this specification.
For the purposes of simplicity of explanation, the methodologies are shown as a series of acts, but one of ordinary skill in the art will recognize that the present invention is not limited by the order of acts described, as some acts may, in accordance with the present invention, occur in other orders and concurrently. Further, those skilled in the art will recognize that the embodiments described in the specification are all of the preferred embodiments, and that the acts and components referred to are not necessarily required by the present invention.
The above description of the method for preparing high-purity cesium metal by one-step metal thermal reduction provided by the invention is provided in detail, and specific examples are applied to illustrate the principle and the implementation of the invention, and the above examples are only used for helping to understand the method and the core idea of the invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (10)
1. A method for preparing high-purity cesium metal by one-step metallothermic reduction, which is characterized by comprising the following steps:
s1, adding dry cesium chloride into a reaction zone of a reaction furnace tube which is clean and dry in a vacuum tube type reduction furnace, carrying out low-temperature vacuumizing and drying, opening a furnace door under the condition of filling inert gas, adding calcium particles into the reaction zone of the reaction furnace tube, stirring and compacting, and completing furnace charging operation;
s2, carrying out primary heating and vacuumizing on the vacuum tube type reduction furnace with the furnace charging operation completed, raising the furnace temperature to 350 ℃, preserving heat for 1-2 hours, stopping vacuumizing, then carrying out secondary heating, raising the furnace temperature to 650-900 ℃, condensing cesium vapor generated by the reaction in a condensation collecting area of a reaction furnace tube to form liquid metal cesium, and collecting the liquid metal cesium by using a collecting bottle to obtain the high-purity metal cesium.
2. The method for preparing high-purity cesium metal by one-step metallothermic reduction according to claim 1, wherein the hearth of the vacuum tube-type reduction furnace is placed at an included angle of 10-15 ° with the horizontal direction;
the condensation collecting area of the reaction furnace tube is provided with a straight-through pipeline which forms an included angle of 60 degrees with the reaction furnace tube and is used for connecting the collecting bottle.
3. The method for preparing high-purity cesium metal by one-step metallothermic reduction according to claim 1, wherein the reaction furnace tube is a straight tube reaction furnace tube, and the condensation collecting area of the reaction furnace tube adopts a heat preservation measure to ensure that the temperature of the condensation collecting area is not lower than 60 ℃.
4. The method for preparing high-purity cesium metal by one-step metallothermic reduction according to claim 1, wherein the purity of cesium chloride is not lower than 99.5%, and the cesium chloride is previously dried in vacuum in a vacuum oven at 200 ℃ for 24 hours before use;
the purity of the calcium particles is more than 95 percent, and the granularity of the calcium particles is less than 3mm.
5. The method for preparing high-purity cesium metal by one-step metallothermic reduction according to claim 1, wherein in step S1, the reaction furnace tube is washed with 3-5% hydrochloric acid and deionized water in sequence before use, and is dried after being washed with ethanol, and the drying method is to raise the furnace temperature of the vacuum tube type reduction furnace to 200 ℃, and the reaction furnace tube is kept open for 4-6 hours.
6. The method for preparing high-purity cesium metal by one-step metallothermic reduction according to claim 1, wherein in step S1, the duration of the low-temperature vacuum drying is 2 hours, and the pressure in the reaction furnace tube is maintained to be not more than 10 - 1 Pa, the temperature is 200 ℃.
7. The method for preparing high-purity metallic cesium in one step by metallothermic reduction according to claim 1, wherein in step S1, the mass ratio of the cesium chloride to the calcium particles is (2-4): 1.
8. the method for preparing high-purity cesium metal by one-step metallothermic reduction according to claim 1, wherein in step S1, the inert gas is argon or nitrogen.
9. The method for preparing high-purity cesium metal by one-step metallothermic reduction according to claim 1, wherein in step S2, the pressure in the reaction furnace tube is not more than 10 when the vacuum pumping is stopped -3 Pa。
10. The method for preparing high purity cesium metal in one step by metallothermic reduction according to claim 1, wherein after step S2, the method further comprises: and closing the valve of the collecting bottle, taking down the collecting bottle, transferring into a glove box, and carrying out hot melting again and split charging.
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| 《稀有金属知识》编写组: "稀有金属知识 锂、铷、铯", 燃料化学工业出版社, pages: 588 - 589 * |
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