Preparation method of ultra-dry anhydrous scandium chloride

Abstract

The invention provides a preparation method of ultra-dry anhydrous scandium chloride, which comprises the following steps: S1, mixing a water-containing scandium chloride raw material with ammonium chloride, and pre-dehydrating to obtain crude anhydrous ScCl3; s2, the coarse anhydrous scandium chloride is placed in a vacuum condition for gradient heating, then distillation purification is conducted, and ultra-dry anhydrous scandium chloride with the absolute purity larger than or equal to 99.99% is obtained; the step S2 is carried out in a reaction kettle, a quartz pore plate is placed above the raw materials in the reaction kettle, and a plurality of adsorption materials are placed above the quartz pore plate. The total amount of ultra-dry anhydrous scandium chloride rare earth prepared by the method reaches 31.59%, the total amount of water-soluble rare earth reaches 31.34%, the water content is less than or equal to 1ppm, the oxygen content is less than or equal to 50ppm, and the single yield reaches 94%.

Description

Technical Field

[0001] This invention belongs to the field of anhydrous scandium chloride preparation technology, and in particular relates to a method for preparing ultra-dry anhydrous scandium chloride. Background Technology

[0002] Scandium is an important rare earth metal element with wide applications in advanced materials fields such as laser crystals, catalysts, lighting sources, special ceramics, and semiconductor devices. Anhydrous scandium chloride is an important intermediate product in the synthesis of scandium and scandium compound materials, used for the direct smelting of metallic scandium or the preparation of scandium master alloys, high-purity scandium oxide, scandium gallium garnet crystals, etc. However, because scandium ions have the smallest ionic radius among all rare earth elements and have the strongest affinity for water, they form intermediate products Sc(OH)Cl2·4H2O and ScOCl·H2O during dehydration, eventually decomposing into Sc2O3. Therefore, developing a dehydration preparation process for scandium chloride is of great significance.

[0003] In the preparation technology of scandium chloride, there are currently two main process routes: wet process and dry process. The wet process involves acidifying scandium oxide with molten salt or hydrochloric acid, and then dehydrating it under a protective atmosphere to prepare anhydrous scandium chloride. However, this process introduces impurities such as ammonium chloride, aluminum chloride, and potassium chloride to form protective double salts, resulting in a product purity that is generally below 99%. The dry process involves co-firing scandium oxide with a reducing agent under a fluorine-containing atmosphere, but this process is complex and cannot be scaled up. Summary of the Invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes a method for preparing ultra-dry anhydrous scandium chloride.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A method for preparing ultra-dry anhydrous scandium chloride includes the following steps: S1: The aqueous scandium chloride raw material is mixed with ammonium chloride and pre-dehydrated to obtain crude anhydrous ScCl3; S2: The crude anhydrous scandium chloride is placed under vacuum and subjected to gradient heating, and then purified by distillation to obtain ultra-dry anhydrous scandium chloride with an absolute purity ≥99.99%. Step S2 is carried out in a reaction vessel, in which a quartz perforated plate is placed above the raw material, and several adsorbent materials are placed above the quartz perforated plate. The adsorbent materials are prepared by the following method: The first step involves polycondensation of silica precursor liquid and template agent in an acidic system, followed by molding, aging, drying and calcination at 380-500℃ to obtain a silica material with a mesoporous structure. The second step is to dry the calcined mesoporous silica material in a vacuum or inert atmosphere to make its surface have an open hydroxyl structure. The third step involves dispersing the dried mesoporous silica material in an anhydrous solvent and then adding silane and epoxy compounds to the system for modification. Step 4: After washing, drying and vacuum desorption, the modified mesoporous silica material is obtained as the final adsorbent material.

[0006] Preferably, the silica precursor is one or more of tetraethyl orthosilicate, methyl orthosilicate, and tetraethoxysilane.

[0007] Preferably, the silane is one or more of 3-aminopropyltriethoxysilane, diethylenetriaminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane.

[0008] Preferably, the epoxy compound is one or more of epichlorohydrin, succinic anhydride, and acetylacetone.

[0009] Preferably, the mass ratio of the mesoporous silica, silane, and epoxy compound is (0.1-0.3):(0.1-0.3):1.

[0010] Preferably, the specific steps of the pre-dehydration in step S1 are as follows: A crude anhydrous scandium chloride is obtained by subjecting aqueous scandium chloride raw material and ammonium chloride to a gradient heating process starting from room temperature under vacuum conditions and in an inert gas or acidic atmosphere.

[0011] Preferably, the vacuum condition in step S1 is a pressure ≤ 1000 Pa; more preferably, the pressure ≤ 300 Pa; and even more preferably, the pressure ≤ 100 Pa.

[0012] Preferably, the vacuum condition in step S2 is a pressure ≤ 100 Pa; more preferably, a pressure ≤ 20 Pa; and even more preferably, a pressure ≤ 10 Pa.

[0013] Preferably, in step S1, the gradient temperature rise is a first temperature range of 200-400℃, and in step S2, the gradient temperature rise is a second temperature range of 500-800℃.

[0014] Preferably, the heating rate of the gradient temperature rise in steps S1 and S2 is ≤15℃ / min. More preferably, the heating rate is ≤10℃ / min; even more preferably, the heating rate is ≤5℃ / min.

[0015] Preferably, the duration of the first temperature range is 14-16 hours; the duration of the second temperature range is 8-12 hours.

[0016] Preferably, the inert gas in steps S1 and S2 is one or more of N2, Ar, and He.

[0017] Preferably, the acidic atmosphere in step S1 is a hydrogen chloride atmosphere or a chlorine atmosphere.

[0018] Preferably, the ambient water content in the drying operation is below 300 ppm.

[0019] Compared with the prior art, the present invention has the following advantages: The total rare earth content of ultra-dry anhydrous scandium chloride prepared by the method of the present invention reaches 31.59%, the total water-soluble rare earth content reaches 31.34%, the water content is ≤1ppm, the oxygen content is ≤50ppm, and the single yield reaches 94%. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the internal structure of the reactor described in Embodiment 1 of the present invention; Figure 2 Photograph of the anhydrous scandium chloride product described in Embodiment 1 of the present invention; Figure 3 This is an XRD fitting diagram of anhydrous scandium chloride as described in Example 1 of the present invention; Figure 4 The N2 adsorption-desorption curves of the adsorption material described in Example 1 of this invention are shown below. Figure 5 This is a pore size distribution diagram of the adsorption material described in Example 1 of the present invention. Detailed Implementation

[0021] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In this document, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0024] In this article, the terms "multiple" or "more than" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0025] In this document, the terms "preferred" and "more preferred" are used only to describe implementation methods or embodiments with better effects, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0026] In this document, terms such as "further" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0027] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0028] In this document, the term "about" means a specified value of + / - 10%, preferably + / - 5%, and more preferably + / - 1%.

[0029] In this article, the terms “include,” “including,” “have,” “contain,” etc., are all open-ended terms, meaning that they include but are not limited to.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0031] This invention provides a method for preparing ultra-dry anhydrous scandium chloride, comprising the following steps: S1: The aqueous scandium chloride raw material is mixed with ammonium chloride and pre-dehydrated to obtain crude anhydrous ScCl3; S2: The crude anhydrous scandium chloride is placed under vacuum and subjected to gradient heating, and then purified by distillation to obtain ultra-dry anhydrous scandium chloride with an absolute purity ≥99.99%. Step S2 is carried out in a reaction vessel, in which a quartz perforated plate is placed above the raw material, and several adsorbent materials are placed above the quartz perforated plate. The adsorbent materials are prepared by: The first step involves polycondensation of silica precursor liquid and template agent in an acidic system, followed by molding, aging, drying and calcination at 380-500℃ to obtain a silica material with a mesoporous structure. The second step is to dry the calcined mesoporous silica material in a vacuum or inert atmosphere to make its surface have an open hydroxyl structure. The third step involves dispersing the dried mesoporous silica material in an anhydrous solvent and then adding silane and epoxy compounds to the system for modification. Step 4: After washing, drying and vacuum desorption, the modified mesoporous silica material is obtained as the final adsorbent material.

[0032] Adding silane introduces nitrogen-containing coordinating groups through condensation anchoring; then adding an epoxy compound anchors the oxygen-containing ligands to the nitrogen-active sites.

[0033] The ligand oxygen atoms in the adsorbent material coordinate and complex with the Sc-O structure in the impurity scandium oxychloride produced during the scandium chloride purification process, which makes the residence time of scandium oxychloride in the pores longer and the flow rate of scandium chloride faster, thus achieving efficient purification of scandium chloride.

[0034] Preferably, the silica precursor is one or more of tetraethyl orthosilicate, methyl orthosilicate, and tetraethoxysilane.

[0035] Based on the differences in melting point, boiling point, and vapor pressure of different substances, the final product ScCl3 is purified by distillation to obtain ultra-dry anhydrous ScCl3 with an absolute purity of ≥99.99%.

[0036] Step S2 is as follows: In the drying room, crude anhydrous ScCl3 is placed into the reactor. After the raw material is added, the reactor is gently shaken to remove the residual gas in the raw material and compact the raw material. A quartz perforated plate is placed on top of the raw material, and several treated adsorbent materials are placed on top of the quartz perforated plate to absorb the sublimation hydrolysis products. The loaded raw material is transferred to a vacuum furnace, and the temperature is gradually increased from room temperature and held until the reaction is completed.

[0037] After the reaction is complete, a protective atmosphere is required for product transfer and packaging. This step requires a glove box with an inert gas atmosphere containing <1 ppm oxygen and <1 ppm water. All discharge tools must be cleaned with pure water, dried, and then transferred to the glove box for later use.

[0038] Preferably, the silane is one or more of 3-aminopropyltriethoxysilane, diethylenetriaminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane.

[0039] Preferably, the epoxy compound is one or more of epichlorohydrin, succinic anhydride, and acetylacetone.

[0040] Preferably, the mass ratio of the mesoporous silica, silane, and epoxy compound is (0.1-0.3):(0.1-0.3):1.

[0041] Preferably, the specific steps of the pre-dehydration in step S1 are as follows: Acidic scandium chloride raw material and ammonium chloride are subjected to a gradient heating process starting from room temperature under vacuum conditions and an inert gas or acidic atmosphere to obtain crude anhydrous scandium chloride.

[0042] Preferably, the vacuum condition in step S1 is a pressure ≤ 1000 Pa; more preferably, the pressure ≤ 300 Pa; and even more preferably, the pressure ≤ 100 Pa.

[0043] Preferably, the vacuum condition in step S2 is a pressure ≤ 100 Pa; more preferably, a pressure ≤ 20 Pa; and even more preferably, a pressure ≤ 10 Pa.

[0044] Preferably, the gradient temperature rise in step S1 is a first temperature range of 200-400℃, and the gradient temperature rise in step S2 is a second temperature range of 500-800℃.

[0045] Preferably, the heating rate of the gradient temperature rise in steps S1 and S2 is ≤15℃ / min. More preferably, the heating rate is ≤10℃ / min; even more preferably, the heating rate is ≤5℃ / min.

[0046] Preferably, the duration of the first temperature segment of the gradient heating in steps S1 and S2 is 14-16 hours; the duration of the second temperature segment is 8-12 hours.

[0047] Preferably, the inert gas in steps S1 and S2 is one or more of N2, Ar, and He.

[0048] Preferably, the acidic atmosphere in step S1 is a hydrogen chloride atmosphere or a chlorine atmosphere.

[0049] Preferably, the ambient water content in the drying operation is below 300 ppm.

[0050] The present invention will be described in detail below with reference to embodiments.

[0051] Example 1 First, 1 part tetraethyl orthosilicate and 0.5 parts P123 template agent were dissolved in an acidic hydrochloric acid environment at pH=2 to carry out a polycondensation reaction. After molding, aging, drying, and calcination at 450℃, a silica material with a mesoporous structure was obtained. The calcined mesoporous silica was then dried in a vacuum to give the material surface an open hydroxyl structure. Next, 1 part of the dried mesoporous silica was dispersed in toluene, and 0.2 parts of 3-aminopropyltriethoxysilane were added to the system to introduce nitrogen-containing coordinating groups through condensation anchoring. Then, 0.2 parts of epichlorohydrin were added to anchor oxygen-containing ligands to the nitrogen-containing active sites. Finally, the modified adsorbent material was washed, dried, and vacuum desorbed to obtain the final adsorbent material (the N2 adsorption-desorption curve of the adsorbent material is shown in Figure 1). Figure 4 As shown, the aperture distribution diagram is as follows: Figure 5 (As shown).

[0052] Weigh out 600g of scandium chloride hydrate and 400g of ammonium chloride, mix them thoroughly, and place them in a quartz boat. Take two quartz trays and place 600g and 200g of molecular sieves respectively. Place the quartz boat containing the scandium chloride and ammonium chloride mixture into a tube furnace. Place the quartz tray containing 600g of molecular sieves at the inlet of the tube furnace and the quartz tray containing 200g of molecular sieves at the tail of the tube furnace. Install the tube furnace, evacuate to below 20Pa, and heat to 390℃ at a rate of 10℃ / min for 15 hours. Transfer the pre-dehydrated anhydrous scandium chloride to a vacuum distillation system. Add a quartz perforated plate above the anhydrous scandium chloride, and place two layers of adsorbent material (such as...) on the quartz perforated plate. Figure 1 (As shown), the vacuum was reduced to below 10 Pa, and the temperature was increased to 617 °C at a rate of 5 °C / min for 8 hours to distill. The distilled ultra-dry anhydrous scandium chloride (as shown) was collected. Figure 2 As shown, the XRD fitting plot is as follows: Figure 3 (As shown).

[0053] Testing revealed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this embodiment was 30.71%, the total amount of water-soluble rare earth was 30.59%, the moisture content was <1ppm, and the single-batch yield was 94.58%.

[0054] Example 2 First, 1 part of methyl orthosilicate and 0.5 parts of P123 template agent were dissolved in an acidic hydrochloric acid environment with pH=2 to carry out a polycondensation reaction. After molding, aging, drying and calcination at 380℃, a silica material with a mesoporous structure was obtained. Then, the calcined mesoporous silica was placed in a nitrogen atmosphere for drying, so that the surface of the material has an open hydroxyl structure. Next, 1 part of the dried mesoporous silica was dispersed in toluene, and 0.1 parts of diethylenetriaminepropyltriethoxysilane and 0.1 parts of succinic anhydride were added to the system for modification. Finally, the modified adsorbent material was washed, dried and vacuum desorbed to obtain the final adsorbent material.

[0055] Weigh out 600g of hydrated scandium chloride and 400g of ammonium chloride, mix them evenly, and place them in a quartz boat. Take two quartz trays and place 600g and 200g of molecular sieves in them, respectively. Place the quartz boat containing the scandium chloride and ammonium chloride mixture into a tube furnace. Place the quartz tray containing 600g of molecular sieves at the inlet of the tube furnace and the quartz tray containing 200g of molecular sieves at the tail of the tube furnace. Install the tube furnace and evacuate it to below 20Pa. Heat it to 200℃ at a rate of 10℃ / min and heat it for 14h. Transfer the pre-dehydrated anhydrous scandium chloride to a vacuum distillation system. Add a quartz perforated plate above the anhydrous scandium chloride and place three layers of adsorbent material on the quartz perforated plate. Evacuate it to below 10Pa and heat it to 500℃ at a rate of 5℃ / min. Distill it for 12h and collect the distilled ultra-dry anhydrous scandium chloride.

[0056] Testing revealed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this embodiment was 30.92%, the total amount of water-soluble rare earth was 30.80%, the moisture content was <1ppm, and the single-batch yield was 93.14%.

[0057] Example 3 First, 1 part tetraethoxysilane and 0.5 parts P123 template agent were dissolved in an acidic hydrochloric acid environment at pH=2 to carry out a polycondensation reaction. After molding, aging, drying and calcination at 500℃, a silica material with a mesoporous structure was obtained. Then, the calcined mesoporous silica was dried under vacuum conditions to make the surface of the material have an open hydroxyl structure. Next, 1 part of the dried mesoporous silica was dispersed in toluene, and 0.3 parts 3-aminopropyltrimethoxysilane and 0.3 parts acetylacetone were added to the system for modification. Finally, the modified adsorbent material was washed, dried and vacuum desorbed to obtain the final adsorbent material.

[0058] Weigh out 600g of hydrated scandium chloride and 400g of ammonium chloride, mix them thoroughly, and place them in a quartz boat. Take two quartz trays and place 600g and 200g of molecular sieves in them, respectively. Place the quartz boat containing the scandium chloride and ammonium chloride mixture into a tube furnace. Place the quartz tray containing 600g of molecular sieves at the inlet of the tube furnace and the quartz tray containing 200g of molecular sieves at the tail of the tube furnace. Install the tube furnace and evacuate it to below 1000Pa. Heat it to 400℃ at a rate of 10℃ / min and heat it for 16h. Transfer the pre-dehydrated anhydrous scandium chloride to a vacuum distillation system. Add a quartz perforated plate above the anhydrous scandium chloride and place three layers of adsorbent material on the quartz perforated plate. Evacuate it to below 100Pa and heat it to 800℃ at a rate of 15℃ / min. Distill it for 8h and collect the distilled ultra-dry anhydrous scandium chloride.

[0059] Testing revealed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this embodiment was 32.45%, the total amount of water-soluble rare earth was 30.91%, the moisture content was <1ppm, and the single-batch yield was 89.32%.

[0060] Comparative Example 1 Weigh out 600g of hydrated scandium chloride and 400g of ammonium chloride, mix them thoroughly, and place them in a quartz boat. Take two quartz trays and place 600g and 200g of molecular sieves in them, respectively. Place the quartz boat containing the scandium chloride and ammonium chloride mixture into a tube furnace. Place the quartz tray containing 600g of molecular sieves at the inlet of the tube furnace and the quartz tray containing 200g of molecular sieves at the tail of the tube furnace. Install the tube furnace, evacuate to below 20Pa, and heat to 390℃ at a rate of 10℃ / min for 14h. Transfer the pre-dehydrated anhydrous scandium chloride to a vacuum distillation system, evacuate to below 10Pa, and distill at 617℃ at a rate of 5℃ / min for 12h. Collect the distilled ultra-dry anhydrous scandium chloride.

[0061] The test results showed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this comparative example was 34.93%, the total amount of water-soluble rare earth was 30.91%, the moisture content was 33 ppm, and the single-batch yield was 73.51%.

[0062] Comparative Example 2 Weigh out 600g of hydrated scandium chloride and 400g of ammonium chloride, mix them thoroughly, and place them in a quartz boat. Take two quartz trays and place 600g and 200g of molecular sieves in them, respectively. Place the quartz boat containing the scandium chloride and ammonium chloride mixture into a tube furnace. Place the quartz tray containing 600g of molecular sieves at the inlet of the tube furnace and the quartz tray containing 200g of molecular sieves at the tail of the tube furnace. Install the tube furnace, evacuate to below 20Pa, and heat to 390℃ at a rate of 10℃ / min for 14h. Transfer the pre-dehydrated anhydrous scandium chloride to a vacuum distillation system, evacuate to below 10Pa, and distill at 617℃ at a rate of 5℃ / min for 10h. Collect the distilled ultra-dry anhydrous scandium chloride.

[0063] The test results showed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this comparative example was 35.45%, the total amount of water-soluble rare earth was 30.91%, the moisture content was 28 ppm, and the single-batch yield was 75.53%.

[0064] Comparative Example 3 Weigh out 600g of hydrated scandium chloride and 400g of ammonium chloride, mix them thoroughly, and place them in a quartz boat. Take two quartz trays and place 600g and 200g of molecular sieves in them, respectively. Place the quartz boat containing the scandium chloride and ammonium chloride mixture into a tube furnace. Place the quartz tray containing 600g of molecular sieves at the inlet of the tube furnace and the quartz tray containing 200g of molecular sieves at the tail of the tube furnace. Install the tube furnace, evacuate to below 20Pa, and heat to 390℃ at a rate of 10℃ / min for 14h. Transfer the pre-dehydrated anhydrous scandium chloride to a vacuum distillation system, evacuate to below 10Pa, and heat to 617℃ at a rate of 5℃ / min for 8h. Collect the distilled ultra-dry anhydrous scandium chloride.

[0065] The test results showed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this comparative example was 34.11%, the total amount of water-soluble rare earth was 31.40%, the moisture content was 46 ppm, and the single-batch yield was 72.86%.

[0066] Comparative Example 4 The difference between this comparative example and Example 1 is that the mesoporous silica was used directly as an adsorbent without modification.

[0067] The test results showed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this comparative example was 33.59%, the total amount of water-soluble rare earth was 31.34%, the moisture content was <1ppm, and the single-batch yield was 79.42%.

[0068] Comparative Example 5 The difference between this comparative example and Example 1 is that the mesoporous silica was modified using only 3-aminopropyltriethoxysilane.

[0069] The test results showed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this comparative example was 31.27%, the total amount of water-soluble rare earth was 30.46%, the moisture content was <1ppm, and the single-batch yield was 80.94%.

[0070] Comparative Example 6 The difference between this comparative example and Example 1 is that the mesoporous silica was modified using only epichlorohydrin.

[0071] The test results showed that the total amount of ultra-dry anhydrous scandium chloride rare earth produced in this comparative example was 32.74%, the total amount of water-soluble rare earth was 31.31%, the moisture content was <1ppm, and the single-batch yield was 82.16%.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing ultra-dry anhydrous scandium chloride, characterized in that: Includes the following steps: S1: The aqueous scandium chloride raw material is mixed with ammonium chloride and pre-dehydrated to obtain crude anhydrous ScCl3; S2: The crude anhydrous scandium chloride is placed under vacuum and subjected to gradient heating, and then purified by distillation to obtain ultra-dry anhydrous scandium chloride with an absolute purity of ≥99.99%. Step S2 is carried out in a reaction vessel, in which a quartz perforated plate is placed above the raw material, and several adsorbent materials are placed above the quartz perforated plate. The adsorbent materials are prepared by the following method: The first step involves polycondensation of silica precursor liquid and template agent in an acidic system, followed by molding, aging, drying and calcination at 380-500℃ to obtain a silica material with a mesoporous structure. The second step is to dry the calcined mesoporous silica material in a vacuum or inert atmosphere. The third step involves dispersing the dried mesoporous silica material in an anhydrous solvent and then adding silane and epoxy compounds to the system for modification. Step 4: After washing, drying and vacuum desorption, the modified mesoporous silica material is used to obtain the adsorbent material.

2. The method for preparing ultra-dry anhydrous scandium chloride according to claim 1, characterized in that: The silica precursor is one or more of tetraethyl orthosilicate, methyl orthosilicate, and tetraethoxysilane; preferably, the silane is one or more of 3-aminopropyltriethoxysilane, diethylenetriaminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane; preferably, the epoxy compound is one or more of epichlorohydrin, succinic anhydride, and acetylacetone; preferably, the mass ratio of the mesoporous silica, silane, and epoxy compound is (0.1-0.3):(0.1-0.3):

1.

3. The method for preparing ultra-dry anhydrous scandium chloride according to claim 1, characterized in that: The specific steps of the pre-dehydration in step S1 are as follows: Acidic scandium chloride raw material and ammonium chloride are subjected to a gradient heating process starting from room temperature under vacuum, inert atmosphere or acidic atmosphere to obtain crude anhydrous scandium chloride.

4. The method for preparing ultra-dry anhydrous scandium chloride according to claim 3, characterized in that: In step S1, the vacuum condition is a pressure ≤ 1000 Pa; preferably, the pressure ≤ 300 Pa; more preferably, the pressure ≤ 100 Pa.

5. The method for preparing ultra-dry anhydrous scandium chloride according to claim 1, characterized in that: The vacuum condition in step S2 is a pressure ≤ 100 Pa; preferably, the pressure ≤ 20 Pa; more preferably, the pressure ≤ 10 Pa.

6. The method for preparing ultra-dry anhydrous scandium chloride according to claim 1, characterized in that: In step S1, the gradient temperature rise is in the first temperature range, which is 200-400℃. In step S2, the gradient temperature rise is in the second temperature range, which is 500-800℃.

7. The method for preparing ultra-dry anhydrous scandium chloride according to claim 1, characterized in that: The heating rate of the gradient heating in steps S1 and S2 is ≤15℃ / min; more preferably, the heating rate is ≤10℃ / min; and even more preferably, the heating rate is ≤5℃ / min.

8. The method for preparing ultra-dry anhydrous scandium chloride according to claim 6, characterized in that: The duration of the first temperature segment of the gradient heating in steps S1 and S2 is 14-16 h; the duration of the second temperature segment is 8-12 h.

9. The method for preparing ultra-dry anhydrous scandium chloride according to claim 1, characterized in that: The inert gas in steps S1 and S2 is one or more of N2, Ar, and He.

10. The method for preparing ultra-dry anhydrous scandium chloride according to claim 1, characterized in that: The acidic atmosphere in step S1 is a hydrogen chloride atmosphere or a chlorine atmosphere.

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