Preparation method and application of anhydrous scandium trichloride

Abstract

The present invention relates to a preparation method and application of anhydrous scandium trichloride. The preparation method of the anhydrous scandium trichloride comprises the following steps: calcining scandium oxide powder in a hydrogen atmosphere to prepare scandium hydride; heating and decomposing the scandium hydride under vacuum conditions to prepare scandium powder; reacting the scandium powder with a chlorination agent to prepare anhydrous scandium trichloride, wherein the chlorination agent is selected from any one or both of chlorine and hydrogen chloride. The preparation method of the scandium trichloride adopts a dry process to avoid the problem that scandium trichloride is easily decomposed during water removal in a wet process, and the method is simple in process and can improve the purity of anhydrous scandium trichloride.

Description

Technical Field

[0001] The invention relates to the field of chemical synthesis, and in particular to a preparation method and application of anhydrous scandium trichloride. Background Art

[0002] Scandium is a lanthanide rare earth element. Its halides are important raw materials for making metal halide lamps, optical fibers, electronic ceramics and laser materials. Among them, scandium trichloride (ScCl3) is the most common and important halide. High-purity anhydrous scandium trichloride is one of the important intermediates in the fine chemical industry and can be used to prepare scandium metal coordination compounds and other inorganic materials.

[0003] Since rare earth elements have similar properties, they are difficult to separate and purify. In addition, anhydrous scandium chloride is relatively active and easily combines with oxygen, carbon dioxide or water in the air to generate scandium oxychloride, which will further decompose into scandium oxide under heating conditions. Therefore, it is difficult to prepare high-purity anhydrous scandium chloride.

[0004] The preparation methods of anhydrous scandium chloride reported so far are mainly divided into two categories: wet method and dry method. The wet process mainly uses molten salt or hydrochloric acid to increase the solubility of scandium oxide to increase the rate of its chlorination reaction, and then dissolves it into a chlorination solution and calcines it in an inert atmosphere to generate anhydrous scandium chloride. For example, some researchers use a molten salt of NaCl-KCl-NH4Cl and AlCl3 to dissolve scandium oxide and then calcine to remove NH4Cl / AlCl3, thereby obtaining anhydrous scandium chloride with a maximum purity of 98.92%. The above-mentioned wet process has a relatively complicated process of removing water and impurities, and the product is very easy to hydrolyze, so it is not easy to obtain high-purity anhydrous scandium chloride.

[0005] The dry process is to mix scandium oxide and reducing substances and then calcine them in a chlorine atmosphere to produce anhydrous scandium trichloride crystals. This method has strict requirements on the pretreatment of raw materials, air flow and temperature control, which is not conducive to industrial scale-up production. For example, in the traditional technology, the pre-purified anhydrous Sc2O3 and carbon black are mixed and calcined at high temperature in a chlorine atmosphere. Summary of the invention

[0006] Based on this, it is necessary to provide a method for preparing anhydrous scandium trichloride, which adopts a dry process to avoid the problem that scandium trichloride is easily decomposed during water removal in a wet process, and the method is simple in process and can improve the purity of anhydrous scandium trichloride.

[0007] In addition, it is necessary to provide an application of anhydrous scandium trichloride.

[0008] A method for preparing anhydrous scandium trichloride comprises the following steps:

[0009] calcining scandium oxide powder in a hydrogen atmosphere to prepare scandium hydride;

[0010] Under vacuum conditions, heating and decomposing the scandium hydride to prepare scandium powder; and

[0011] The scandium powder is reacted with a chlorination agent to prepare anhydrous scandium trichloride, wherein the chlorination agent is selected from any one or both of chlorine and hydrogen chloride.

[0012] In one embodiment, the step of calcining the scandium oxide powder in a hydrogen atmosphere satisfies any one or two of the following conditions:

[0013] (1) The calcination temperature is 400°C to 900°C;

[0014] (2) The calcination time is 1h to 5h.

[0015] In one embodiment, the step of calcining the scandium oxide powder in a hydrogen atmosphere satisfies any one or two of the following conditions:

[0016] (1) The calcination temperature is 650°C to 800°C;

[0017] (2) The calcination time is 2h to 3h.

[0018] In one embodiment, the temperature of the thermal decomposition is 100°C to 800°C.

[0019] In one embodiment, the step of heating and decomposing the scandium hydride under vacuum conditions comprises:

[0020] Under vacuum conditions, the scandium hydride is heated from 10°C to 200°C to 500°C to 700°C for thermal decomposition at a heating rate of 5°C / min to 10°C / min.

[0021] In one embodiment, before the step of reacting the scandium powder with a chlorination agent, the method further comprises: repeatedly calcining the scandium powder in a hydrogen atmosphere, and then heating and decomposing the scandium powder under vacuum at least once.

[0022] In one embodiment, the chlorination agent is chlorine gas.

[0023] In one embodiment, the step of subjecting the scandium powder to a chlorination reaction comprises: igniting the scandium powder and the chlorination reagent to react with each other, and heating every 30 minutes until the reaction is complete 2 to 3 hours after the ignition.

[0024] In one embodiment, the scandium oxide powder has a D 50 The particle size is 40μm~500μm.

[0025] In one embodiment, the anhydrous scandium trichloride has a D 50 The particle size is 10μm~50μm.

[0026] The invention discloses an application of anhydrous scandium trichloride in preparing a coordination compound of scandium. The anhydrous scandium trichloride is prepared by the above-mentioned preparation method of anhydrous scandium trichloride.

[0027] The preparation method of the anhydrous scandium trichloride is to first reduce scandium oxide by hydrogenation, and then decompose it by vacuum to obtain scandium powder. The purity and reactivity of the scandium powder are improved by the above reaction. Then, the scandium powder is subjected to a chlorination reaction with at least one of chlorine and hydrogen chloride, thereby avoiding the introduction of other impurities during the product preparation process, thereby causing the product impurity element detection to exceed the standard, and greatly improving the purity of the prepared anhydrous scandium trichloride. In addition, the reaction conditions and equipment of the above method are relatively simple, and the operation steps are simple, which is conducive to further industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a process flow chart of a method for preparing anhydrous scandium trichloride according to one embodiment. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with the specific embodiments. Preferred embodiments of the present invention are provided in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0031] Unless otherwise specified or there is a contradiction, the terms or phrases used in this invention have the following meanings:

[0032] In the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0033] In the present invention, "one or several" refers to any one, any two or any two or more of the listed items. Among them, "several" refers to any two or any two or more.

[0034] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0035] In the present invention, when a numerical range is involved, unless otherwise specified, the two endpoints of the numerical range are included.

[0036] In the present invention, the percentage concentration involved, unless otherwise specified, refers to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of the component.

[0037] The words "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0038] When a numerical range is disclosed in the present invention, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0039] In the present invention, the temperature parameters involved, if not specifically limited, allow both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range of the instrument control. Unless otherwise specified, in this article, room temperature refers to a temperature of 10°C to 30°C.

[0040] The terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or components that are inherent to these processes, methods, products, or devices.

[0041] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present invention may be combined with other embodiments.

[0042] The traditional preparation method of anhydrous scandium trichloride introduces other substances into the reaction system, thereby causing the impurity elements of the finished scandium trichloride to be high, the product purity is low, and the reaction device is complicated and the reaction conditions are harsh, which is not conducive to industrial amplification. The process of wet high-temperature calcination of the chloride salt of scandium is used to prepare anhydrous scandium trichloride. The process of removing water and impurities is relatively complicated and the product is very easy to hydrolyze, and it is not easy to obtain high-purity anhydrous scandium chloride. The inventor found in the experiment that the key point of preparing high-purity anhydrous scandium trichloride is not only to use suitable process means to improve the reaction efficiency of the chlorination reaction, but also to control the atmosphere in the reactor, use an inert atmosphere or evacuate, so as to avoid the product hydrolysis to generate by-products.

[0043] Based on this, the present invention provides a dry preparation process for anhydrous scandium trichloride to solve the problems of insufficient purity and harsh conditions of anhydrous scandium trichloride in the traditional dry preparation process and easy decomposition of scandium trichloride during water removal in the wet process.

[0044] Specifically, see Figure 1 , a method for preparing anhydrous scandium trichloride according to an embodiment of the present invention comprises the following steps:

[0045] Step S110: calcining the scandium oxide powder in a hydrogen atmosphere to prepare scandium hydride.

[0046] In a saturated hydrogen atmosphere, the scandium oxide powder is reduced to metallic scandium by hydrogen, and the metallic scandium and hydrogen further generate hydrides. Using hydrogen reduction conditions, on the one hand, no other impurities are introduced, and high-purity metallic scandium is obtained by generating hydrides of scandium, and then decomposing them by vacuum heating. On the other hand, the generation of hydrides can further obtain fine and uniform metal powders, rather than metal particles, and finally obtain powdered anhydrous scandium trichloride. Using other reduction conditions, such as C reduction or CO reduction, although metallic scandium can be obtained, other impurities are introduced, and the purity of the obtained anhydrous scandium trichloride is low. In addition, using C reduction or CO reduction, metal particles are obtained, and the scandium trichloride finally obtained is granular, and further processing in a glove box is required to obtain powdered anhydrous scandium chloride, which increases the difficulty of the process.

[0047] In some embodiments, the calcination temperature is 400° C. to 900° C. In a specific example, the calcination temperature may be, but is not limited to, 400° C., 450° C., 500° C., 550° C., 600° C., 650° C., 680° C., 700° C., 720° C., 750° C., 780° C., 800° C., 850° C., 900° C., or a range consisting of any two of these values. Preferably, the calcination temperature is 650° C. to 800° C.

[0048] In some embodiments, the calcination time is 1 h to 5 h. In a specific example, the calcination time can be, but is not limited to, 1 h, 1.5 h, 2 h, 2.2 h, 2.5 h, 2.8 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, or a range consisting of any two of these values. Preferably, the calcination time is 2 h to 3 h.

[0049] In some embodiments, the scandium oxide powder has a purity of 90% to 99%.

[0050] In some embodiments, the scandium oxide powder has a D 50 The particle size is 40 μm to 500 μm. In a specific example, the D 50 The particle size is 40 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm or a range consisting of any two of these values. Experiments have shown that the preparation method of anhydrous scandium trichloride using the present embodiment does not require a complicated pretreatment process for the raw materials. Pretreatment is of little significance to improving the purity of anhydrous scandium trichloride, and the reaction conditions of the preparation method of anhydrous scandium trichloride using the present embodiment are relatively simple, and the operating steps are simple, which is conducive to further industrial production and has great practical prospects.

[0051] In some embodiments, step S110 includes: calcining the scandium oxide powder at 400° C. to 900° C. in a hydrogen atmosphere for 1 h to 5 h to prepare a scandium hydride. Further, step S110 includes: calcining the scandium oxide powder at 650° C. to 800° C. in a hydrogen atmosphere for 2 h to 3 h to prepare a scandium hydride.

[0052] Step S120: Under vacuum conditions, the hydride of scandium is heated and decomposed to prepare scandium powder.

[0053] In some embodiments, in step S120, the temperature of the thermal decomposition is 100° C. to 800° C. In a specific example, the temperature of the thermal decomposition may be, but is not limited to, 100° C., 200° C., 300° C., 400° C., 500° C., 600° C., 700° C., 800° C., or a range consisting of any two of these values. Preferably, the temperature of the thermal decomposition is 200° C. to 700° C.

[0054] In some embodiments, step S120 includes: under vacuum conditions, heating the hydride of scandium from 10°C to 200°C to 500°C to 700°C for thermal decomposition, and the heating rate is 5°C / min to 10°C / min. In a specific example, the heating rate is 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min or a range consisting of any two of these values. Preferably, in one embodiment, step S120 includes: under vacuum conditions, heating the hydride of scandium from 200°C to 700°C for thermal decomposition, and the heating rate is 5°C / min.

[0055] Slow heating is more helpful in decomposing hydrides into fine powders. Direct heating to a higher temperature before introducing hydrides may result in incomplete decomposition and the formation of large particles, and there are also safety risks.

[0056] It can be understood that in some embodiments, after the calcination in step S110 is completed and the temperature is lowered to room temperature or to room temperature to 200° C., the hydride is heated and decomposed under vacuum. This method is conducive to decomposing the hydride into fine and uniform powder, and the operation is safer.

[0057] In this embodiment, there is no particular limitation on the vacuuming conditions, and the vacuuming state only needs to be maintained continuously.

[0058] Step S130: Repeat the steps of calcining the scandium powder in a hydrogen atmosphere and then heating and decomposing the scandium powder under vacuum at least once to prepare purified scandium powder.

[0059] In some embodiments, the step of calcining scandium powder in a hydrogen atmosphere is the same as the step of calcining in step S110, and will not be repeated. The step of heating and decomposing under vacuum conditions is the same as the step of heating and decomposing in step S120, and will not be repeated. It can be understood that in step S130, the calcination temperature and time can be the same as or different from the temperature and time in step S110, as long as they are within the temperature and time range. Similarly, in step S130, the temperature of heating and decomposing under vacuum conditions can be the same as or different from the temperature in step S120, as long as they are within the above range.

[0060] The purity of the prepared scandium powder can be further improved through the above steps. It can be understood that in some embodiments, if the purity requirement for the scandium powder is not high, step S130 may not be performed.

[0061] It can be understood that the step of repeatedly calcining the scandium powder in a hydrogen atmosphere and then heating and decomposing it under vacuum conditions at least once means that calcining in a hydrogen atmosphere and then heating and decomposing it under vacuum conditions is a cycle, and the cycle is performed once, twice, three times, etc. in step S130. Further, the step of repeatedly calcining the scandium powder in a hydrogen atmosphere and then heating and decomposing it under vacuum conditions is repeated twice to three times. Step S140: reacting the purified scandium powder with a chlorination agent to prepare anhydrous scandium trichloride.

[0062] In some embodiments, the chlorine reagent is selected from any one or a combination of chlorine and hydrogen chloride. Using other chlorination reagents such as carbon tetrachloride, the carbon element is introduced, and the purity of the prepared scandium trichloride is significantly lower, and the particles are larger. Preferably, the chlorination reagent is chlorine. Experiments have shown that the purity of the prepared scandium trichloride can be further improved by using chlorine for chlorination reaction.

[0063] In some embodiments, step S140 includes: igniting the purified scandium powder and the chlorination reagent, and heating every 30 minutes until the reaction is complete after 2 hours to 3 hours of ignition. In the actual process, the color of scandium trichloride is white and the scandium powder is gray, so the end point of the reaction can be judged according to the color change. At the beginning of the reaction, the ignition device needs to be started to ignite, and the reaction can proceed spontaneously without heating after the reaction starts. After reacting for 2 hours to 3 hours, the reactor is heated every 30 minutes to maintain the reaction rate until the scandium powder reacts completely.

[0064] In some embodiments, excess chlorine from the reaction can be absorbed in an ice-water bath of calcium chloride.

[0065] The above-mentioned preparation method of anhydrous scandium trichloride has at least the following advantages:

[0066] (1) The above-mentioned preparation method of anhydrous scandium trichloride is to obtain high-purity scandium powder by hydrogenation reduction of scandium oxide, followed by vacuum decomposition, and then directly chlorination, thereby avoiding the introduction of other impurities in the product preparation process, which would lead to excessive detection of impurity elements in the product, and greatly improving the purity of the prepared anhydrous scandium trichloride.

[0067] (2) The above-mentioned preparation method of anhydrous scandium chloride improves the purity and reaction activity of scandium powder by adding a cycle of hydrogenation reduction and then vacuum calcination decomposition during the production process, thereby improving the efficiency of the subsequent chlorination reaction process, saving the energy consumption required for the reaction, and reducing production costs.

[0068] (3) The above-mentioned preparation method of anhydrous scandium chloride can obtain uniform and fine scandium powder through the reduction-decomposition cycle step, thereby ensuring that the generated anhydrous scandium trichloride is also in powder form rather than granular form, which is more conducive to practical application.

[0069] (4) The reaction conditions and equipment of the above-mentioned preparation method of anhydrous scandium chloride are relatively simple, and the operation steps are simple, which is conducive to further industrial production and has great practical prospects.

[0070] The anhydrous scandium trichloride prepared by the method for preparing anhydrous scandium trichloride according to the above embodiment has high purity.

[0071] In some embodiments, the purity of the anhydrous scandium chloride is ≥96%. Further, the purity of the anhydrous scandium chloride is ≥98%. The impurity element content of the anhydrous scandium chloride is less than 20 ppm. Further, the purity of the anhydrous scandium chloride is ≥99%. Further, the purity of the anhydrous scandium chloride is ≥99.5%.

[0072] In some embodiments, the anhydrous scandium chloride is in powder form. 50 The particle size is 10 μm to 50 μm. In a specific example, the D 50 The particle size is 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or a range consisting of any two of these values. The anhydrous scandium chloride has high purity and low content of impurities. The anhydrous scandium chloride is in powder form, which is more conducive to practical application.

[0073] The present invention also provides an implementation method of using anhydrous scandium trichloride in preparing a coordination compound of scandium.

[0074] The anhydrous scandium trichloride has high purity and low content of impurity elements, and can be used to prepare scandium coordination compounds.

[0075] In order to make the purpose and advantages of the present invention clearer, the preparation method of anhydrous scandium trichloride of the present invention and its effect are further described in detail below in conjunction with specific examples. It should be understood that the specific examples described herein are only used to explain the present invention and shall not be used to limit the present invention. The following examples do not include other components except inevitable impurities unless otherwise specified. The drugs and instruments used in the examples are conventionally selected in this area unless otherwise specified. The experimental methods for which specific conditions are not specified in the examples are implemented according to conventional conditions, such as the conditions described in the literature, books, or the methods recommended by the manufacturer.

[0076] Example 1

[0077] This embodiment provides a method for preparing anhydrous scandium trichloride, which specifically comprises the following steps:

[0078] (1) 10 g of scandium oxide powder (D) with a purity of 99% 50 The particle size is 41.1 microns) and calcined and reduced at 800°C in hydrogen for 3 hours to generate scandium hydride.

[0079] (2) After the reduction is completed and the temperature drops to room temperature, the scandium hydride is heated to 700°C at a rate of 5°C / min under vacuum to decompose into scandium powder.

[0080] (3) After the temperature of the reaction in step (2) drops to room temperature, the scandium powder obtained in the previous step (2) is calcined in a hydrogen atmosphere at 800°C for 3 hours. After the reduction is completed and the temperature drops to room temperature, the scandium hydride is heated to 700°C at a rate of 5°C / min while maintaining vacuum to decompose and obtain purified scandium powder.

[0081] (4) After dry chlorine gas was introduced into the reactor for 10 minutes, the chlorination reaction was started and anhydrous scandium trichloride began to be generated. After the reaction lasted for 2 hours, the reactor was heated every 30 minutes to maintain the system temperature at 500° C. The reaction was continued for 10 hours until all the scandium powder was chlorinated to generate anhydrous scandium trichloride.

[0082] Example 2

[0083] This embodiment provides a method for preparing anhydrous scandium trichloride. The specific preparation process is similar to that of Example 1, except that step (3) is added between step (3) and step (4), that is, in this embodiment, a cumulative cycle of hydrogenation reduction and vacuum calcination is performed three times, and the other steps are the same as those of Example 1.

[0084] Example 3

[0085] This embodiment provides a method for preparing anhydrous scandium trichloride. The specific preparation process is similar to that of embodiment 2, except that in step (1), the scandium oxide powder is further ground and pulverized to obtain a scandium oxide powder D 50 The particle size is 19.6 μm, and the other steps are the same as in Example 2.

[0086] Example 4

[0087] This embodiment provides a method for preparing anhydrous scandium trichloride. The specific preparation process is similar to that of Example 2, except that in step (1), the hydrogen reduction temperature is 500° C., and the other steps are the same as those of Example 2.

[0088] Example 5

[0089] This embodiment provides a method for preparing anhydrous scandium trichloride. The specific preparation process is similar to that of Example 2, except that in step (4), hydrogen chloride is used instead of chlorine in the chlorination process, and the other steps are the same as those of Example 2.

[0090] Example 6

[0091] This embodiment provides a method for preparing anhydrous scandium trichloride. The specific preparation process is similar to that of Example 2, except that during the vacuum calcination process in step (2), the temperature is raised to 500° C. The other steps are the same as those of Example 2.

[0092] Example 7

[0093] This embodiment provides a method for preparing anhydrous scandium trichloride. The specific preparation process is similar to that of Example 2, except that step (3) is added between step (3) and step (4), that is, in this embodiment, a total of four cycles of hydrogenation reduction and vacuum calcination are performed, and the other steps are the same as those of Example 2.

[0094] Example 8

[0095] This embodiment provides a method for preparing anhydrous scandium trichloride. The specific preparation process is similar to that of Embodiment 1, except that step (3) is not performed.

[0096] Comparative Example 1

[0097] Comparative Example 1 provides a method for preparing anhydrous scandium trichloride, and the specific process is as follows:

[0098] Using the method described in Acta Chem Scand, 1994, 48, 294, 10 g of scandium oxide and 5 g of carbon black were mixed and calcined at 900° C. in a chlorine atmosphere for 5 hours to finally obtain large-particle anhydrous scandium trichloride crystals.

[0099] Comparative Example 2

[0100] Comparative Example 2 provides a method for preparing anhydrous scandium trichloride, and its specific preparation process is similar to that of Example 1, except that the hydrogen reduction condition in step (1) is replaced by CO reduction, and the other steps are the same as those in Example 1.

[0101] Comparative Example 3

[0102] Comparative Example 3 provides a method for preparing anhydrous scandium trichloride, and its specific preparation process is similar to that of Example 2, except that in step (4), carbon tetrachloride is used instead of chlorine in the chlorination process, and the other steps are the same as those of Example 2.

[0103] The element type, purity, particle size, etc. of the anhydrous scandium trichloride prepared in the above-mentioned embodiments and comparative examples were tested to obtain the experimental data shown in Table 1 below.

[0104] Table 1 Experimental characterization data of anhydrous scandium trichloride prepared in each embodiment and comparative example

[0105]

[0106] It can be seen from the above data that the preparation method of anhydrous scandium trichloride in the above embodiment can obtain anhydrous scandium trichloride with a maximum purity of >99.5%, and increasing the number of hydrogenation reduction and vacuum calcination decomposition can significantly improve the purity of the prepared scandium trichloride. Further grinding and pretreatment of scandium oxide powder in Example 3 is not very helpful for improving the purity of the prepared scandium trichloride, which indirectly proves that anhydrous scandium trichloride with a sufficiently high purity can be obtained by adopting the above preparation method, without further complicated pretreatment of the raw materials, or pretreatment is of little significance for improving the purity of the product.

[0107] In Comparative Example 1, the conventional dry process is used, and the purity of the prepared scandium trichloride is low and the particle size is large, and it needs to be crushed in a glove box in the subsequent process to obtain powdered scandium trichloride. In Comparative Example 2, carbon monoxide reduction is used instead of hydrogen reduction, and the other steps are the same, and the purity of the prepared scandium trichloride is significantly lower than that of the embodiment.

[0108] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The above-described embodiments only express several implementation methods of the present invention, which is convenient for understanding the technical solutions of the present invention in detail, but cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the protection scope of the claims attached to the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the contents of the attached claims, and the description and drawings can be used to interpret the contents of the claims.

Claims

1. A method for preparing anhydrous scandium trichloride, characterized in that: The steps include: calcining scandium oxide powder in a hydrogen atmosphere to prepare scandium hydride; Under vacuum conditions, heating and decomposing the scandium hydride to prepare scandium powder; and reacting the scandium powder with a chlorination agent to prepare anhydrous scandium trichloride, wherein the chlorination agent is selected from any one or both of chlorine and hydrogen chloride; Before the step of reacting the scandium powder with a chlorination agent, the method further includes: repeatedly calcining the scandium powder in a hydrogen atmosphere, and then heating and decomposing the scandium powder under vacuum conditions at least once.

2. The method for preparing anhydrous scandium trichloride according to claim 1, characterized in that: The step of calcining the scandium oxide powder in a hydrogen atmosphere satisfies any one or both of the following conditions: (1) The calcination temperature is 400°C to 900°C; and (2) The calcination time is 1h~5h.

3. The method for preparing anhydrous scandium trichloride according to claim 2, characterized in that: The step of calcining the scandium oxide powder in a hydrogen atmosphere satisfies any one or both of the following conditions: (1) The calcination temperature is 650°C to 800°C; and (2) The calcination time is 2h~3h.

4. The method for preparing anhydrous scandium trichloride according to claim 1, characterized in that: The temperature of the heating decomposition is 500-800°C.

5. The method for preparing anhydrous scandium trichloride according to claim 4, characterized in that: The step of heating and decomposing the scandium hydride under vacuum conditions comprises: Under vacuum conditions, the scandium hydride is heated from 10°C to 200°C to 500°C to 700°C for thermal decomposition at a heating rate of 5°C / min to 10°C / min.

6. The method for preparing anhydrous scandium trichloride according to any one of claims 1 to 5, characterized in that: The scandium powder is repeatedly calcined in a hydrogen atmosphere and then heated and decomposed under vacuum conditions for two to three times.

7. The method for preparing anhydrous scandium trichloride according to any one of claims 1 to 5, characterized in that: The step of subjecting the scandium powder to a chlorination reaction comprises: igniting the scandium powder and the chlorination reagent to allow the scandium powder and the chlorination reagent to react, and heating every 30 minutes until the reaction is complete 2h to 3h after the ignition.

8. The method for preparing anhydrous scandium trichloride according to any one of claims 1 to 5, characterized in that: The scandium oxide powder has a D 50 The particle size is 40μm~500μm.

9. The method for preparing anhydrous scandium trichloride according to claim 8, characterized in that: The anhydrous scandium trichloride D 50 The particle size is 10μm~50μm.

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