CN112683008A - Method for preparing anhydrous rare earth halide by vacuum microwave dehydration - Google Patents
Method for preparing anhydrous rare earth halide by vacuum microwave dehydration Download PDFInfo
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Abstract
The invention provides a method for preparing anhydrous rare earth halide by vacuum microwave dehydration, comprising the steps of filling the rare earth halide containing crystal water into a container, and placing the container in a vacuum microwave drying oven for dehydration treatment, wherein the dehydration temperature is 60-260 ℃; the temperature of the vacuum microwave drying box is programmed to rise, the vacuum degree is between-0.09 MPa and-0.1 MPa, and the microwave frequency is 2450MHz +/-50 Hz. The method provided by the invention can realize simultaneous heating of the inside and the outside of the crystal water-containing rare earth halide, the dehydration rate of each part of the crystal water-containing rare earth halide tends to be consistent, the heating is uniform, the temperature rise is fast, the generation of byproducts can be effectively inhibited, the dehydration efficiency is high, the dehydration time is greatly shortened, and the water content of the finally obtained anhydrous rare earth halide is less than or equal to 0.5%.
Description
Technical Field
The invention belongs to the technical field of preparation of anhydrous halogenated rare earth, and particularly relates to a method for preparing anhydrous halogenated rare earth by vacuum microwave dehydration.
Background
The anhydrous halogenated rare earth is an important raw material in the manufacturing industry, and has important and wide application prospect in the fields of luminescent materials, heat insulating materials, hydrogen storage materials, ceramic materials, catalysis, military industry and the like. Since anhydrous rare earth halide is very easy to react with water and oxygen in the air, a large amount of rare earth oxyhalide impurities are easily generated by side reactions in the process of preparing the anhydrous rare earth halide, so that the preparation of the anhydrous rare earth halide is very difficult.
At present, the main method for preparing anhydrous rare earth halide is to dehydrate the rare earth halide containing crystal water to prepare the anhydrous rare earth halide. The rare earth halide containing crystal water is LnX 3. nH2O, wherein Ln is any one element of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc, X is any one element of Cl and Br, and n is less than or equal to 7.
The method for dehydrating the halogenated rare earth containing the crystal water comprises the following steps: 1. directly heating and dehydrating in air, 2, heating and dehydrating under the protection of inert atmosphere or vacuum, 3, heating and dehydrating under the protection of ammonium halide, and 4, introducing hydrogen halide gas, heating and dehydrating under the protection of hydrogen halide gas. The method is directly heated in the air atmosphere, and water and oxygen in the air easily generate side reaction with anhydrous rare earth halide, so that the prepared anhydrous rare earth halide contains a large amount of halogen-oxidized rare earth impurities; in order to inhibit the occurrence of side reactions, dehydration is carried out under the condition of introducing protective atmosphere or vacuum, and the method can inhibit the occurrence of side reactions to a certain extent under the condition of strictly controlling the temperature rise rate and the temperature interval; the method that the ammonium halide protects and dehydrates is adopted by the Gerd Meyer, and the hydrogen halide gas decomposed by heating the ammonium halide can effectively inhibit the occurrence of side reactions and prepare purer anhydrous rare earth halide; the hydrogen halide gas is directly introduced to protect dehydration, so that side reactions can be well avoided, and the ideal dehydration effect is achieved. The above-mentioned several heating dehydration modes all belong to external heating type heating dehydration mode. The external heating type heating dehydration is that heat is transferred to the surface of the rare earth halide containing crystal water from the outside, and then the heat is gradually transferred to the inside, so that the dehydrated rare earth halide on the surface is easily reacted with the water dehydrated from the inside, the rare earth oxyhalide is easily generated on the surface, and the pure anhydrous rare earth halide can be obtained only by stripping the rare earth oxyhalide generated on the surface, so that the one-time yield of the anhydrous rare earth halide is reduced; the external heating dehydration requires a long time to transfer heat to the rare earth halide containing crystal water, so that the dehydration period is long, and a large heat loss is caused in the heat transfer process.
The existing heating dehydration methods have the problems of long dehydration time, low efficiency and high energy consumption, and the time consumption is 16 hours or even more than 24 hours.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a method for preparing anhydrous halogenated rare earth by vacuum microwave dehydration, microwave is used for heating and dehydrating the halogenated rare earth containing crystal water in a vacuum environment, electromagnetic waves are used as a heating source for microwave dehydration, water molecules of materials absorb the microwave to cause the vibration of the water molecules, and thus the materials are heated; the heating mode can heat the inside and the outside of the material simultaneously, the dehydration rate of each part of the material tends to be consistent, and the material dehydration device has the characteristics of uniform heating, high temperature rise, high dehydration efficiency and the like.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method for preparing anhydrous rare earth halide by vacuum microwave dehydration comprises the steps of filling the rare earth halide containing crystal water into a container, and placing the container in a vacuum microwave drying oven for dehydration treatment, wherein the dehydration temperature is 60-260 ℃.
Further, the temperature of the vacuum microwave drying box is raised by a program, the temperature is raised to 60-90 ℃ from the normal temperature in the first stage, and the temperature is kept for 2-30 min; in the second stage, the temperature is continuously increased to 130-160 ℃, and the temperature is kept for 2-40 min; in the third stage, the temperature is continuously increased to 210-260 ℃, and the temperature is kept for 3-120 min.
Further, the vacuum degree of the vacuum microwave drying box is between-0.09 MPa and-0.1 MPa.
Further, the microwave frequency of the microwave magnetron of the vacuum microwave drying oven is 2450MHz +/-50 Hz.
Further, the dehydration time is 10min to 180 min.
Compared with the prior art, the method for preparing anhydrous halogenated rare earth by vacuum microwave dehydration provided by the invention has the following advantages:
1. the method adopts a vacuum microwave dehydration mode to uniformly heat the material, so that the condition of generating rare earth oxyhalide due to local overheating is avoided, the influence of water and oxygen in the air on the dehydration process is avoided under the vacuum atmosphere condition, and the occurrence of side reaction is greatly inhibited;
2. the vacuum microwave dehydration adopted by the method is to heat and dehydrate the inside of the halogenated rare earth containing crystal water, so that the anhydrous halogenated rare earth generated on the surface can not generate side reaction, the quality indexes of the inside and the surface of the obtained anhydrous halogenated rare earth are consistent, and the one-time yield of the anhydrous halogenated rare earth is improved; meanwhile, the materials are heated from the inside, so that the heat energy utilization rate is high, the energy utilization rate is improved, and the energy loss is reduced;
3. the vacuum microwave dehydration adopted by the method directly transfers heat to the interior of the crystal water-containing rare earth halide, has high heating speed, greatly shortens the dehydration time, only needs 1 to 3 hours, improves the equipment utilization rate, and has high dehydration efficiency, and the water content of the anhydrous rare earth halide is less than or equal to 0.5 percent.
Detailed Description
The present invention will be described in detail with reference to examples.
Example 1
Placing 800g of 33% water content cerium chloride heptahydrate in a ceramic container, then placing the ceramic container in a vacuum microwave drying oven, wherein the radiation frequency of a microwave magnetron is 2450MHz, the output power is 2000W, vacuumizing the equipment, keeping the vacuum degree at-0.09 MPa, keeping the temperature in the equipment at 80 ℃ for 20min, keeping the temperature at 150 ℃ for 40min, keeping the temperature at 250 ℃ for 60min, cooling, taking out the material, adding anhydrous cerium chloride into water for rapid dissolution, and detecting and analyzing that the water content of the anhydrous cerium chloride is 0.38% and the purity of the anhydrous cerium chloride is more than 99.5%.
Example 2
3000g of neodymium chloride hexahydrate with the water content of 30% is placed in a ceramic container, then the ceramic container is placed in a vacuum microwave drying oven, the radiation frequency of a microwave magnetron is 2450MHz, the output power is 6000W, the equipment is vacuumized, the vacuum degree is kept at-0.094 MPa, the temperature in the equipment is 80 ℃ and is kept for 10min, the temperature is increased to 150 ℃ and is kept for 30min, then the temperature is increased to 240 ℃ and is kept for 100min, the material is taken out after cooling, anhydrous neodymium chloride is added into water to be rapidly dissolved, the dissolved water solution is clear and transparent, the water content of the anhydrous neodymium chloride is detected and analyzed to be 0.35%, and the purity of the anhydrous neodymium chloride is more than 99.5%.
Example 3
200g of lanthanum bromide heptahydrate with the water content of 25 percent is placed in a ceramic container, then the ceramic container is placed in a vacuum microwave drying oven, the radiation frequency of a microwave magnetron is 2450MHz, the output power is 1000W, the equipment is vacuumized, the vacuum degree is kept at-0.097 MPa, the temperature in the equipment is 60 ℃, the temperature is kept for 5min when the temperature is raised to 130 ℃, the temperature is kept for 10min when the temperature is raised to 220 ℃, the material is taken out after cooling, anhydrous lanthanum bromide is added into water to be rapidly dissolved, the dissolved aqueous solution is clear and transparent, the water content of the anhydrous lanthanum bromide is detected and analyzed to be 0.43 percent, and the purity of the anhydrous lanthanum bromide is more than 99.5 percent.
Example 4
2000g of samarium bromide hexahydrate with the water content of 22% is placed in a ceramic container, then the ceramic container is placed in a vacuum microwave drying oven, the emission frequency of a microwave magnetron is 2450MHz, the output power is 1000W, the equipment is vacuumized, the vacuum degree is kept at-0.093 MPa, the temperature in the equipment is 80 ℃, the temperature is kept for 20min, the temperature is increased to 160 ℃, the temperature is kept for 30min, then the temperature is increased to 250 ℃, the material is taken out after cooling, anhydrous samarium bromide is added into water to be rapidly dissolved, the dissolved aqueous solution is clear and transparent, the water content of the anhydrous samarium bromide is detected and analyzed to be 0.32%, and the purity of the anhydrous samarium bromide is more than 99.5%.
Example 5
100g of neodymium bromide hexahydrate with the water content of 22% is placed in a ceramic container, then the ceramic container is placed in a vacuum microwave drying oven, the radiation frequency of a microwave magnetron is 2450MHz, the output power is 1000W, the equipment is vacuumized, the vacuum degree is kept at-0.095 MPa, the temperature range in the equipment is 80 ℃, the temperature is kept for 5min, the temperature is increased to 160 ℃, the temperature is kept for 10min, then the temperature is increased to 260 ℃, the material is taken out after cooling, anhydrous neodymium bromide is added into water to be rapidly dissolved, the dissolved water solution is clear and transparent, the water content of the anhydrous neodymium bromide is detected and analyzed to be 0.01%, and the purity of the anhydrous neodymium bromide is more than 99.5%.
Example 6
50g of 29 percent moisture content erbium chloride hexahydrate is placed in a ceramic container, then the ceramic container is placed in a vacuum microwave drying oven, the radiation frequency of a microwave magnetron is 2450MHz, the output power is 1000W, the equipment is vacuumized, the vacuum degree is kept at-0.094 MPa, the temperature range in the equipment is 75 ℃, the temperature is kept for 2min when the temperature is raised to 140 ℃, the temperature is kept for 3min when the temperature is raised to 210 ℃, the material is taken out after cooling, anhydrous erbium chloride is added into water to be rapidly dissolved, the dissolved aqueous solution is clear and transparent, the moisture content of the anhydrous erbium chloride is detected and analyzed to be 0.22 percent, and the purity of the anhydrous erbium chloride is more than 99.5 percent.
Example 7
1500g of lutetium chloride hexahydrate with the water content of 23 percent is placed in a ceramic container, then the ceramic container is placed in a vacuum microwave drying box, the radiation frequency of a microwave magnetron is 2450MHz, the output power is 1000W, the equipment is vacuumized, the vacuum degree is kept at-0.098 MPa, the temperature in the equipment is kept at 85 ℃ for 30min, the temperature is increased to 150 ℃ for 40min, then the temperature is increased to 220 ℃ for 50min, the material is taken out after cooling, anhydrous lutetium chloride is added into water to be rapidly dissolved, the dissolved aqueous solution is clear and transparent, the water content of the anhydrous lutetium chloride is detected and analyzed to be 0.43 percent, and the purity of the anhydrous lutetium chloride is more than 99.5 percent.
Comparative example 1
3000g of neodymium chloride hexahydrate with the water content of 30% is placed in a ceramic container, then the ceramic container is placed in a vacuum oven, the equipment is vacuumized, the vacuum degree is kept at-0.094 MPa, the temperature in the equipment is 80 ℃ and is kept for 30min, the temperature is raised to 150 ℃ and is kept for 90min, the temperature is raised to 240 ℃ and is kept for 200min, the material is taken out after being cooled, the anhydrous neodymium chloride is added into water to generate obvious white turbidity, the water content of the anhydrous neodymium chloride is 0.34% through detection and analysis, and the purity of the anhydrous neodymium chloride is 88.2%.
Comparative example 2
3000g of neodymium chloride hexahydrate with the water content of 30% and 2000g of ammonium chloride are uniformly mixed and then placed in a ceramic container, then the ceramic container is placed in a vacuum oven, the equipment is vacuumized, the vacuum degree is kept at-0.094 MPa, the temperature range in the equipment is 80 ℃, the temperature is kept for 20min, the temperature is raised to 150 ℃, the temperature is kept for 60min, the temperature is raised to 240 ℃, the temperature is kept for 200min, the material is taken out after cooling, the material is transferred into a tube furnace, ammonium is removed by heating under the argon atmosphere, the temperature range in the tube furnace is kept for 300min at 450 ℃, the product is taken out after cooling, the obtained anhydrous neodymium chloride is added into water to be rapidly dissolved, the dissolved water solution is clear and transparent, the moisture content of the anhydrous neodymium chloride is 0.33% and the purity of the anhydrous neodymium chloride is 98.3% through detection and analysis.
Comparative example 3
3000g of neodymium chloride hexahydrate with the water content of 30% is placed into a tube furnace, heating and dehydration are carried out under the atmosphere of hydrogen chloride, the temperature in the tube furnace is kept at 450 ℃ for 600min, the product is taken out after cooling, the obtained anhydrous neodymium chloride is added into water to be rapidly dissolved, the water content of the anhydrous neodymium chloride is 0.33% through detection and analysis, the water solution after dissolution is clear and transparent, and the purity of the anhydrous neodymium chloride is 97.4%.
Comparative example 1 a vacuum oven is directly adopted for heating, the heating mode is hot air heating, the purity of the obtained product is low, and byproducts are generated; in the comparative example 2, ammonium chloride is adopted for protection and dehydration, so that the process is complex and long in time consumption; in the comparative example 3, hydrogen chloride gas is adopted for protection, heating and dehydration, a large amount of hydrogen chloride gas is consumed, the time is long, and the cost is high. As can be seen from the comparison between examples 1 to 7 and comparative examples 1 to 3, the vacuum microwave dehydration method can effectively inhibit the occurrence of side reactions, and the solution after dissolution is clear and has high purity, short time consumption and high dehydration efficiency.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (5)
1. A method for preparing anhydrous halogenated rare earth by vacuum microwave dehydration is characterized in that: filling the rare earth halide containing crystal water into a container, and putting the container into a vacuum microwave drying oven for dehydration treatment, wherein the dehydration temperature is 60-260 ℃.
2. The method for preparing anhydrous rare earth halide by vacuum microwave dehydration according to claim 1, wherein the method comprises the following steps: the vacuum microwave drying oven is heated by a program, the temperature is raised to 60-90 ℃ from the normal temperature in the first stage, and the temperature is kept for 2-30 min; in the second stage, the temperature is continuously increased to 130-160 ℃, and the temperature is kept for 2-40 min; in the third stage, the temperature is continuously increased to 210-260 ℃, and the temperature is kept for 3-120 min.
3. The method for preparing anhydrous rare earth halide by vacuum microwave dehydration according to claim 1, wherein the method comprises the following steps: the vacuum degree of the vacuum microwave drying box is between-0.09 MPa and-0.1 MPa.
4. The method for preparing anhydrous rare earth halide by vacuum microwave dehydration according to claim 1, wherein the method comprises the following steps: the microwave frequency of the microwave magnetron of the vacuum microwave drying box is 2450MHz +/-50 Hz.
5. The method for preparing anhydrous rare earth halide by vacuum microwave dehydration according to claim 1, wherein the method comprises the following steps: the dehydration time is 10 min-180 min.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113336256A (en) * | 2021-06-17 | 2021-09-03 | 虔东稀土集团股份有限公司 | Preparation method of anhydrous rare earth neodymium chloride |
| CN113991167A (en) * | 2021-10-26 | 2022-01-28 | 西安交通大学 | Halide solid electrolyte material and preparation method and application thereof |
| CN114017999A (en) * | 2021-11-17 | 2022-02-08 | 云南锡业锡化工材料有限责任公司 | Method for preparing anhydrous stannous chloride in vacuum by microwave |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4045639A (en) * | 1973-01-16 | 1977-08-30 | Food Processing Systems Corporation | Continuous microwave and vacuum dryer |
| CN102538423A (en) * | 2012-02-10 | 2012-07-04 | 周跃云 | Microwave vacuum drier |
| CN103234339A (en) * | 2013-05-02 | 2013-08-07 | 昆明理工大学 | Device for ilmenite concentrate microwave drying and application method thereof |
| CN103743203A (en) * | 2014-01-17 | 2014-04-23 | 河南勃达微波设备有限责任公司 | Vanadium pentoxide catalyst microwave-drying process |
| CN204460975U (en) * | 2015-02-07 | 2015-07-08 | 陕西理工学院 | A kind of heating using microwave ratary disk type drying machine for powdery chemical material |
| CN107726740A (en) * | 2016-08-10 | 2018-02-23 | 云南民族大学 | A kind of method of micro-wave vacuum high titanium slag |
| US10309722B1 (en) * | 2013-03-14 | 2019-06-04 | International Research Institute Inc. | Microwave and vacuum drying device, system, and related methods |
| CN105783427B (en) * | 2016-04-14 | 2019-06-18 | 华南理工大学 | A kind of microwave vacuum drying method of control by stages |
-
2020
- 2020-12-24 CN CN202011554133.5A patent/CN112683008A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4045639A (en) * | 1973-01-16 | 1977-08-30 | Food Processing Systems Corporation | Continuous microwave and vacuum dryer |
| CN102538423A (en) * | 2012-02-10 | 2012-07-04 | 周跃云 | Microwave vacuum drier |
| US10309722B1 (en) * | 2013-03-14 | 2019-06-04 | International Research Institute Inc. | Microwave and vacuum drying device, system, and related methods |
| CN103234339A (en) * | 2013-05-02 | 2013-08-07 | 昆明理工大学 | Device for ilmenite concentrate microwave drying and application method thereof |
| CN103743203A (en) * | 2014-01-17 | 2014-04-23 | 河南勃达微波设备有限责任公司 | Vanadium pentoxide catalyst microwave-drying process |
| CN204460975U (en) * | 2015-02-07 | 2015-07-08 | 陕西理工学院 | A kind of heating using microwave ratary disk type drying machine for powdery chemical material |
| CN105783427B (en) * | 2016-04-14 | 2019-06-18 | 华南理工大学 | A kind of microwave vacuum drying method of control by stages |
| CN107726740A (en) * | 2016-08-10 | 2018-02-23 | 云南民族大学 | A kind of method of micro-wave vacuum high titanium slag |
Non-Patent Citations (1)
| Title |
|---|
| 唐宗薰: "《中级无机化学》", 31 May 2003, 高等教育出版社 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113336256A (en) * | 2021-06-17 | 2021-09-03 | 虔东稀土集团股份有限公司 | Preparation method of anhydrous rare earth neodymium chloride |
| CN113991167A (en) * | 2021-10-26 | 2022-01-28 | 西安交通大学 | Halide solid electrolyte material and preparation method and application thereof |
| CN114017999A (en) * | 2021-11-17 | 2022-02-08 | 云南锡业锡化工材料有限责任公司 | Method for preparing anhydrous stannous chloride in vacuum by microwave |
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Application publication date: 20210420 |