阅读说明：本技术 一种无水氯化亚钐及其制备方法 (Anhydrous samarium chloride and preparation method thereof ) 是由 汪瑞 张瑞森 高淞 李璐 张光睿 赵长玉 彭维 王安丽 于 2021-10-18 设计创作，主要内容包括：本发明创造提供了一种无水氯化亚钐及其制备方法,所述方法首先在真空条件下脱去水合氯化钐中的结晶水,然后将无水氯化钐与金属M反应,并经过除杂及真空蒸馏过程,得到绝对纯度极高的无水氯化亚钐。除杂及蒸馏过程中在高真空环境中进行,严格隔绝了水和氧,避免产品被污染；此外工艺流程较短,操作简便,易于工业化生产。(The invention provides anhydrous samarium chloride and a preparation method thereof. The impurity removal and distillation processes are carried out in a high vacuum environment, water and oxygen are strictly isolated, and the product is prevented from being polluted; in addition, the process flow is short, the operation is simple and convenient, and the industrial production is easy to realize.)

1. A preparation method of anhydrous samarium chloride is characterized by comprising the following steps: the method comprises the following steps:

s1: taking hydrated samarium chloride as a raw material, and performing gradient temperature rise dehydration under a vacuum condition to obtain crude anhydrous samarium chloride with most of crystal water removed;

s2: mixing the crude anhydrous samarium chloride and the metal M in the step S1, placing the mixture in a vacuum furnace, and performing gradient temperature rise to 680-700 ℃ under the vacuum condition to perform reaction and impurity removal processes; wherein the metal M is a simple substance with stronger reducibility than samarium, and the melting boiling point of the chloride of the metal M is different from that of samarium chloride;

s3: replacing the impurity removal collecting device, continuously heating the mixture obtained in the step S2 to 740 and 760 ℃ under the vacuum condition, and carrying out the vacuum distillation process to obtain high-quality anhydrous SmCl with the absolute purity of more than or equal to 99.99 percent₂And (5) producing the product.

2. The method of producing anhydrous samarium chloride according to claim 1, comprising: the metal M is Li, Na, K, Ca, Mg, Sm or La.

3. The method of producing anhydrous samarium chloride according to claim 2, comprising: the molar ratio of the crude anhydrous samarium chloride to the metal M in the step S2 is n: 1, reacting the metal M with crude anhydrous samarium chloride to generate MCl_xWhere n is equal to x.

4. The method of producing anhydrous samarium chloride according to claim 1, comprising: the step S1 of gradient temperature rise dehydration comprises the following three steps:

s11: heating to 160 ℃ and 180 ℃, and preserving the heat for 2-3 hours to ensure that SmCl is generated₃·6H₂Removing part of crystal water from O to obtain SmCl₃·yH₂O, wherein y is less than or equal to 1;

s12: on the basis of the step S11, the temperature is continuously increased to 240 ℃ and is kept for 2-3h to ensure that the SmCl is generated₃·yH₂Continuously removing crystal water from the O;

s13: and (4) continuously heating to 240-260 ℃ on the basis of the step S12, and preserving the temperature for 2-3h to obtain crude anhydrous samarium chloride with most of crystal water removed after the reaction is finished.

5. The method of producing anhydrous samarium chloride according to claim 1, comprising: the gradient temperature rise in the step (2) comprises the following two steps:

s21: heating to 500-540 deg.C, and keeping the temperature for 3-4h to make anhydrous samarium chloride and metal M completely react to generate corresponding SmCl₂And MCl_x；

S22: on the basis of the step S21, the temperature is continuously raised to 680-700 ℃, and the temperature is kept for 3-4h, impurities and SmCl are utilized₂And SmCl₃The difference of melting point, boiling point and vapor pressure, the removal of low boiling impurities and small amount of residual SmCl in the raw materials₃。

6. The method of producing anhydrous samarium chloride according to claim 1, comprising: the vacuum degree in the step S1 is 0.001MPa-0.01 MPa.

7. The method of producing anhydrous samarium chloride according to claim 1, comprising: the degree of vacuum in the step S2 is not more than 10 Pa.

8. The method of producing anhydrous samarium chloride according to claim 1, comprising: the degree of vacuum in step S3 is not more than 0.1 Pa.

9. An anhydrous samarium chloride prepared by the method of any one of claims 1 to 8, wherein: the purity of the anhydrous samarium chloride reaches 99.99 percent, the content of metal impurities is less than 1ppm, and the content of water and oxygen is not more than 20 ppm.

Technical Field

The invention belongs to the field of rare earth material preparation, and particularly relates to anhydrous samarium chloride and a preparation method thereof.

Background

The rare earth element is a general name of lanthanide series elements and yttrium in IIIB group in the periodic table, is an element with strategic position in 21 st century, has unique physical and chemical properties of light, electricity, magnetism and the like, is widely applied to various fields of national economy and national defense industry, and is called as 'treasury of new materials in 21 st century'.

The high-purity anhydrous rare earth halide is an important chemical raw material, is a core raw material for preparing high-purity rare earth metal and a new generation of high-performance rare earth scintillation crystal, and has extremely wide application prospect. However, during the preparation process, rare earth halides are very easy to undergo hydrolysis reaction to generate oxyhalides, which adversely affects the performance of rare earth materials prepared from the rare earth halides.

It is well known that rare earth elements are generally stable in trivalent form in various compounds. And a few rare earth elements such as samarium, europium, thulium and the like can exist in a bivalent metastable state besides a trivalent stable state, wherein Sm²⁺Has stronger reducing capability, larger ionic radius and strong oxygen affinity. Thus, the divalent samarium compound is attracting more and more attention. Anhydrous samarium chloride in the divalent samarium compound has strong reducibility and is easy to generate amino compounds. The invention provides a method for preparing anhydrous samarium chloride, which is simple and feasible to operate and has pure product quality, and has important significance for material research.

Disclosure of Invention

In view of the above, the present invention provides an anhydrous samaric chloride and a preparation method thereof, aiming at overcoming the defects in the prior art.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a preparation method of anhydrous samarium chloride comprises the following steps:

s1: taking hydrated samarium chloride as a raw material, and performing gradient temperature rise dehydration under a vacuum condition to obtain crude anhydrous samarium chloride with most of crystal water removed;

s2: mixing the crude anhydrous samarium chloride and the metal M in the step S1, placing the mixture in a vacuum furnace, and performing gradient temperature rise to 680-700 ℃ under the vacuum condition to perform reaction and impurity removal processes; wherein the metal M is a simple substance with stronger reducibility than samarium, and the melting boiling point of the chloride of the metal M is different from that of samarium chloride;

s3: replacing the impurity removal collecting device, continuously heating the mixture obtained in the step S2 to 740 and 760 ℃ under the vacuum condition, and carrying out the vacuum distillation process to obtain high-quality anhydrous SmCl with the absolute purity of more than or equal to 99.99 percent₂And (5) producing the product.

Preferably, the metal M is Li, Na, K, Ca, Mg, Sm or La.

Preferably, the molar ratio of the crude anhydrous samarium chloride to the metal M in the step S2 is n: 1, the metal M and crude anhydrous samarium chloride generate MCl_xWhere n is equal to x.

Preferably, the step S1 of gradient temperature-rising dehydration includes the following three steps:

s11: heating to 160 ℃ and 180 ℃, and preserving the heat for 2-3 hours to ensure that SmCl is generated₃·6H₂Removing part of crystal water from O to obtain SmCl₃·yH₂O, wherein y is less than or equal to 1;

s12: on the basis of the step S11, the temperature is continuously increased to 240 ℃ and is kept for 2-3h to ensure that the SmCl is generated₃·yH₂Continuously removing crystal water from the O;

s13: and (4) continuously heating to 240-260 ℃ on the basis of the step S12, and preserving the temperature for 2-3h to obtain crude anhydrous samarium chloride with most of crystal water removed after the reaction is finished.

Preferably, the temperature gradient in step (2) includes the following two steps:

s21: heating to 500-540 deg.C, and keeping the temperature for 3-4h to make anhydrous samarium chloride and metal M completely react to generate corresponding SmCl₂And MCl_x；

S22: on the basis of the step S21, the temperature is continuously raised to 680-700 ℃, and the temperature is kept for 3-4h, impurities and SmCl are utilized₂And SmCl₃The difference of melting point, boiling point and vapor pressure, the removal of low boiling impurities and small amount of residual SmCl in the raw materials₃。

Preferably, the degree of vacuum in the step S1 is 0.001MPa to 0.01 MPa.

Preferably, the degree of vacuum in step S2 is not greater than 10 Pa.

Preferably, the degree of vacuum in step S3 is not greater than 0.1 Pa.

The invention also provides the anhydrous samarium chloride prepared by the method, wherein the purity of the anhydrous samarium chloride reaches 99.99 percent, the content of metal impurities is less than 1ppm, and the content of water and oxygen is not more than 20 ppm.

The preparation method of anhydrous samarium chloride obtains crude anhydrous SmCl through treatment₃Then, the reaction, impurity removal and distillation processes are carried out in vacuum, water-free and oxygen-free environments, and in the impurity removal process, SmCl can be compared with SmCl in the raw materials₂Impurities with large saturated vapor pressure (e.g. FeCl)₂、CaCl₃NaCl, residual carbon, etc.) are removed; during the distillation, the target SmCl is given appropriate temperature₂Evaporated and collected by evaporation to SmCl₂More impurity substances with small vapor pressure remain in the material pipe, so that the purposes of strictly removing water and oxygen and highly separating the impurity substances from oxyhalides and oxides are achieved, and finally the high-quality anhydrous SmCl with extremely low impurity elements, water and oxygen contents is obtained₂。

Compared with the prior art, the invention has the following advantages:

according to the preparation method, firstly, crystal water in the hydrated samarium chloride is removed under the vacuum condition, then the anhydrous samarium chloride reacts with the metal M which has stronger reducibility than the samarium chloride and larger difference between the melting boiling point of the metal chloride and the samarium chloride, so that the anhydrous samarium chloride with extremely high absolute purity can be obtained through the processes of impurity removal and vacuum distillation. The impurity removal and distillation processes are carried out in a high vacuum environment, water and oxygen are strictly isolated, and the product is prevented from being polluted; in addition, the process flow is short, the operation is simple and convenient, and the industrial production is easy to realize.

Drawings

FIG. 1 is a schematic flow chart of the preparation method of the present invention.

Detailed Description

Unless defined otherwise, technical terms used in the following examples have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods are conventional methods unless otherwise specified.

The invention will be described in detail with reference to the following examples.

Example 1:

weighing 1000g of hydrated samarium chloride, placing the hydrated samarium chloride in vacuum equipment, vacuumizing the system to be below 0.01MPa, starting gradient programmed temperature rise dehydration, and preserving heat at 160 ℃, 220 ℃ and 250 ℃ for 3 hours respectively to obtain about 705g of crude anhydrous samarium chloride with most of crystal water removed. Mixing crude anhydrous samarium chloride and magnesium metal according to a molar ratio of 2:1 (wherein the crude anhydrous samarium chloride is slightly excessive), transferring the mixture into a vacuum distillation device, vacuumizing the vacuum distillation device (the vacuum degree is less than or equal to 10Pa), and starting to heat to 520 ℃ for heat preservation for 4 hours to ensure that the crude anhydrous samarium chloride and the magnesium metal are completely reacted; the temperature is then increased further to 700 c to remove low boiling impurities from the feed, at which point magnesium chloride is sublimed. And after the collector is replaced, vacuumizing (the vacuum degree is less than or equal to 0.1Pa), continuously heating to 760 ℃ and preserving the temperature for 4 hours, receiving the distilled samarium chloride, and cooling to obtain the high-purity anhydrous samarium chloride.

Through detection and analysis, the product obtained in the embodiment is anhydrous samarium chloride, the metallic impurity elements such as Fe, Ca, Cu and the like are less than or equal to 1ppm, the water content is less than or equal to 20ppm, the oxygen content is less than or equal to 20ppm, and the absolute purity of the high-purity anhydrous samarium chloride is more than or equal to 99.99%.

Example 2:

weighing 500g of hydrated samarium chloride, placing the hydrated samarium chloride in vacuum equipment, vacuumizing the system to be below 0.01MPa, starting gradient programmed temperature rise dehydration, and preserving heat at 180 ℃, 240 ℃ and 260 ℃ for 2 hours respectively to obtain about 353g of crude anhydrous samarium chloride with most of crystal water removed. Mixing crude anhydrous samarium chloride and metal calcium according to a molar ratio of 2:1 (wherein the crude anhydrous samarium chloride is slightly excessive), transferring the mixture into a vacuum distillation device, vacuumizing the vacuum distillation device (the vacuum degree is less than or equal to 10Pa), and starting to heat to 550 ℃ for 3 hours to ensure that the crude anhydrous samarium chloride and the metal magnesium are completely reacted; then the temperature is continuously increased to 700 ℃ to remove the low boiling point impurities in the raw materials. And after the collector is replaced, vacuumizing (the vacuum degree is less than or equal to 0.1Pa), continuously heating to 760 ℃ and preserving the temperature for 3 hours, receiving the distilled samarium chloride, and cooling to obtain the high-purity anhydrous samarium chloride.

Through detection and analysis, the product obtained in the embodiment is anhydrous samarium chloride, the metallic impurity elements such as Fe, Ca, Cu and the like are less than or equal to 1ppm, the water content is less than or equal to 20ppm, the oxygen content is less than or equal to 20ppm, and the absolute purity of the high-purity anhydrous samarium chloride is more than or equal to 99.99%.

Example 3:

weighing 500g of hydrated samarium chloride, placing the hydrated samarium chloride in vacuum equipment, vacuumizing the system to be below 0.01MPa, starting gradient programmed temperature rise dehydration, and preserving heat at 180 ℃, 240 ℃ and 260 ℃ for 2h respectively to obtain about 350g of crude anhydrous samarium chloride with most of crystal water removed. Mixing crude anhydrous samarium chloride and metal lanthanum according to a stoichiometric ratio of 3:1 (wherein the crude anhydrous samarium chloride is slightly excessive), transferring the mixture into a vacuum distillation device, vacuumizing the vacuum distillation device (the vacuum degree is less than or equal to 10Pa), and starting to heat to 550 ℃ for 3 hours to ensure that the crude anhydrous samarium chloride and the metal lanthanum are completely reacted; then the temperature is continuously increased to 700 ℃ to remove the low boiling point impurities in the raw materials. And after the collector is replaced, vacuumizing (the vacuum degree is less than or equal to 0.1Pa), continuously heating to 760 ℃ and preserving the temperature for 3 hours, receiving the distilled samarium chloride, and cooling to obtain the high-purity anhydrous samarium chloride.

Through detection and analysis, the product obtained in the embodiment is anhydrous samarium chloride, the metallic impurity elements such as Fe, Ca, Cu and the like are less than or equal to 1ppm, the water content is less than or equal to 20ppm, the oxygen content is less than or equal to 20ppm, and the absolute purity of the high-purity anhydrous samarium chloride is more than or equal to 99.99%.

Example 4:

weighing 1000g of hydrated samarium chloride, placing the hydrated samarium chloride in vacuum equipment, vacuumizing the system to be below 0.01MPa, starting gradient programmed temperature rise dehydration, and preserving heat at 180 ℃, 240 ℃ and 260 ℃ for 2h respectively to obtain about 711g of crude anhydrous samarium chloride with most of crystal water removed. Mixing crude anhydrous samarium chloride and metal samarium according to a stoichiometric ratio of 2:1 (wherein the crude anhydrous samarium chloride is slightly excessive), transferring the mixture into a vacuum distillation device, vacuumizing the vacuum distillation device (the vacuum degree is less than or equal to 10Pa), and starting to heat to 550 ℃ for 3 hours to ensure that the crude anhydrous samarium chloride and the metal samarium are completely reacted; then the temperature is continuously increased to 700 ℃ to remove the low boiling point impurities in the raw materials. And after the collector is replaced, vacuumizing (the vacuum degree is less than or equal to 0.1Pa), continuously heating to 760 ℃ and preserving the temperature for 3 hours, receiving the distilled samarium chloride, and cooling to obtain the high-purity anhydrous samarium chloride.

Through detection and analysis, the product obtained in the embodiment is anhydrous samarium chloride, the metallic impurity elements such as Fe, Ca, Cu and the like are less than or equal to 1ppm, the water content is less than or equal to 20ppm, the oxygen content is less than or equal to 20ppm, and the absolute purity of the high-purity anhydrous samarium chloride is more than or equal to 99.99%.

Example 5:

weighing 500g of hydrated samarium chloride, placing the hydrated samarium chloride in vacuum equipment, vacuumizing the system to be below 0.01MPa, starting gradient programmed temperature rise dehydration, and preserving heat at 180 ℃, 240 ℃ and 260 ℃ for 2h respectively to obtain 355g of crude anhydrous samarium chloride with most of crystal water removed. Mixing crude anhydrous samarium chloride and metal potassium according to a stoichiometric ratio of 1:1 (wherein the crude anhydrous samarium chloride is slightly excessive), transferring the mixture into a vacuum distillation device, vacuumizing the vacuum distillation device (the vacuum degree is less than or equal to 10Pa), and starting to heat to 550 ℃ for 3 hours to ensure that the crude anhydrous samarium chloride and the metal potassium are completely reacted; then the temperature is continuously increased to 700 ℃ to remove the low boiling point impurities in the raw materials. And after the collector is replaced, vacuumizing (the vacuum degree is less than or equal to 0.1Pa), continuously heating to 760 ℃ and preserving the temperature for 3 hours, receiving the distilled samarium chloride, and cooling to obtain the high-purity anhydrous samarium chloride.

Through detection and analysis, the product obtained in the embodiment is anhydrous samarium chloride, the metallic impurity elements such as Fe, Ca, Cu and the like are less than or equal to 1ppm, the water content is less than or equal to 20ppm, the oxygen content is less than or equal to 20ppm, and the absolute purity of the high-purity anhydrous samarium chloride is more than or equal to 99.99%.

Comparative example 1

Weighing 500g of hydrated samarium chloride, placing the hydrated samarium chloride in vacuum equipment, vacuumizing the system to be below 0.01MPa, starting gradient programmed temperature rise dehydration, and preserving heat at 180 ℃, 240 ℃ and 260 ℃ for 2h respectively to obtain about 350g of crude anhydrous samarium chloride with most of crystal water removed. Mixing the crude anhydrous samarium chloride and the metal lanthanum according to the stoichiometric ratio of 1:1, transferring the mixture into a vacuum distillation device, vacuumizing the vacuum distillation device (the vacuum degree is less than or equal to 10Pa), starting to heat to 550 ℃, preserving the heat for 3 hours, and reducing samarium in the crude anhydrous samarium chloride by using the metal lanthanum to obtain the metal samarium and the metal lanthanum chloride. The samarium and the lanthanum chloride can not be sublimated at 760 ℃, products can not be collected in the vacuum distillation process, and the samarium and the lanthanum chloride remain in the charging bucket as solid compounds after cooling.

Comparative example 2

Weighing 500g of hydrated samarium chloride, placing the hydrated samarium chloride in vacuum equipment, vacuumizing the system to be below 0.01MPa, starting gradient programmed temperature rise dehydration, and preserving heat at 180 ℃, 240 ℃ and 260 ℃ for 2h respectively to obtain about 350g of crude anhydrous samarium chloride with most of crystal water removed. Mixing the crude anhydrous samarium chloride and the calcium metal according to the stoichiometric ratio of 2:3, transferring the mixture into a vacuum distillation device, vacuumizing the vacuum distillation device (the vacuum degree is less than or equal to 10Pa), starting to heat to 550 ℃, preserving the heat for 3 hours, and reducing the samarium in the crude anhydrous samarium chloride by the calcium metal to obtain the samarium metal and the calcium chloride. The metal samarium and the calcium chloride can not be sublimated at 760 ℃, products can not be collected in the vacuum distillation process, and solid compounds are remained in the charging bucket after cooling.

In the above embodiment, the addition amount of the metal M needs to be strictly controlled according to the stoichiometric ratio, and the amount of the crude anhydrous samarium chloride is controlled to be slightly excessive, so as to ensure that the synthesis reaction is carried out in a required direction.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the invention, so that any modifications, equivalents, improvements and the like, which are within the spirit and principle of the present invention, should be included in the scope of the present invention.