Crucible for smelting or purifying metal beryllium and preparation method thereof

Abstract

The invention discloses a crucible for smelting or purifying metallic beryllium, which comprises a metallic oxide ceramic crucible substrate, and the inner wall of the metallic oxide ceramic crucible substrate is coated with a beryllium oxide layer. The preparation method comprises the following steps: taking two metal oxide ceramic crucibles with the same specification as matrixes, putting one crucible on the lower layer and filling metal beryllium, and putting the other crucible upside down on the upper layer to form a reaction container, putting the reaction container in a vacuum melting furnace, and heating to the temperature above the beryllium melting point under the condition of negative pressure for melting; and then reducing the absolute pressure of the vacuum melting furnace, preserving heat, and finally cooling to room temperature to obtain the ceramic crucible with the inner wall coated with the beryllium oxide layer. According to the crucible for smelting or purifying the metal beryllium, the adopted matrix crucible is a conventional metal oxide ceramic crucible, compared with a special beryllium oxide crucible, the effect on the same level as the special beryllium oxide crucible can be achieved when the crucible is applied to the field of smelting of the metal beryllium, and the manufacturing cost can be reduced by 99% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of beryllium metallurgy, and in particular relates to a crucible for smelting or purifying metal beryllium and a preparation method thereof. Background Art

[0002] Metallic beryllium has excellent physical and chemical properties such as low density, specific stiffness, specific heat capacity, high thermal conductivity and corrosion resistance, as well as excellent nuclear performance. It is used in the preparation of satellite frame parts and structures, satellite mirrors, rocket nozzles, gyroscopes and navigation and weapon control components, electronic packaging, data communication system high-power laser mirrors, nuclear fission and fusion reactors and other fields.

[0003] At present, in the field of metal beryllium smelting, such as metal beryllium casting, vacuum distillation and impurity removal of metal beryllium, the best crucibles that can be selected are all beryllium oxide crucibles. Because metal beryllium is very active, it will react chemically with various crucible materials such as graphite, magnesium oxide, aluminum oxide, zirconium oxide, etc. Therefore, conventional beryllium oxide crucibles are not suitable for the smelting or purification of metal beryllium. The high stability of beryllium oxide crucibles is particularly suitable for melting metals with high purity requirements, such as Be, Zr, Ti, etc., and it is also the best crucible material for melting high-purity metal uranium. However, beryllium oxide crucibles are expensive, which is hundreds of times the price of common crucibles (MgO, Al2O3, graphite, etc.); on the other hand, when preparing beryllium oxide crucibles, it is necessary to first prepare ceramic materials with a particle size of 2-3μm, and then obtain beryllium oxide ceramics through molding and sintering processes. In this process flow, the toxicity of beryllium oxide powder will have higher requirements on production equipment and conditions.

[0004] Therefore, it is necessary to develop a low-cost crucible for smelting or purifying metal beryllium to meet the needs of high-purity beryllium preparation and high-performance metal beryllium casting. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a crucible for smelting or purifying metal beryllium and a preparation method thereof.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is: A crucible for smelting or purifying metal beryllium comprises a metal oxide ceramic crucible substrate, the inner wall of which is covered with a beryllium oxide layer.

[0007] In the above-mentioned crucible for smelting or purifying metal beryllium, preferably, the thickness of the beryllium oxide layer is 40-100 μm.

[0008] In the above-mentioned crucible for smelting or purifying metal beryllium, preferably, the metal oxide ceramic crucible substrate comprises one of an alumina crucible and a magnesia crucible.

[0009] Based on a general inventive concept, the present invention also provides a method for preparing a crucible for smelting or purifying metal beryllium, comprising the following steps: (1) Take two metal oxide ceramic crucibles of the same specifications as the base, place one of the crucibles at the bottom and put metal beryllium in it, and then put the other crucible upside down at the top to form a reaction vessel; (2) placing the reaction vessel consisting of the two crucibles in step (1) in a vacuum melting furnace, heating it to a temperature above the melting point of beryllium under negative pressure conditions for melting, and reacting the inner wall of the crucible with the metal beryllium to form a beryllium oxide layer on the inner wall of the crucible; (3) Lowering the absolute pressure of the vacuum melting furnace and maintaining the temperature, so that the metallic beryllium in the reaction vessel can be completely volatilized and escaped from the gap between the two crucibles; (4) After cooling to room temperature and cleaning the high melting point impurities in the metallic beryllium remaining in the crucible, a ceramic crucible with an inner wall covered with a beryllium oxide layer is obtained.

[0010] In the above-mentioned preparation method, preferably, in step (1), the amount of metal beryllium added is Obtained through the following calculation formula:

[0011] in, m Be is the amount of metallic beryllium added, in g; M Be and M BeO are the relative molar masses of Be and BeO, 9 g / mol and 25 g / mol, respectively; ρ is the density of BeO, about 3.01 g / cm 3 , S is the surface area of ​​the reactor inner wall, in cm 2 ; h is the thickness of the beryllium oxide product layer generated during the smelting process, in cm; N For calculation of the constant, the preferred value range is 20-50.

[0012] In the above preparation method, preferably, in step (1), a graphite condensation device can be installed outside the reaction container to collect beryllium vapor escaping from the reaction container.

[0013] In the above preparation method, preferably, in step (2), during the smelting process, the following reaction occurs at the interface of the inner wall of the crucible: MgO (s) + Be (l, g) = BeO (s) + Mg (g)(1); Al2O3(s) + 3Be(l, g) = 3BeO(s) + 2Al(g) (2).

[0014] The dense beryllium oxide generated by the reaction adheres to the inner wall of the crucible, forming a high-melting-point product layer with uniform thickness, dense structure and stable properties, which can protect the inside of the crucible from corrosion by metallic beryllium, while the Mg or Al in the product evaporates in gaseous form under vacuum conditions.

[0015] In the above preparation method, preferably, in step (2), the melting temperature is controlled to be 1350-1600°C, and the reaction vessel as a whole should be kept in a constant temperature range, so that the thickness of the beryllium oxide product layer can reach stability in a relatively short time, thereby preventing further reaction between the crucible and the metal beryllium; the absolute pressure during the melting process is 300-3000Pa. At a melting temperature of 1350-1600°C, the saturated vapor pressure of metal beryllium is 11-256Pa. Controlling the vacuum degree to be 300-3000Pa can not only prevent the metal beryllium from volatilizing too quickly and in large quantities, resulting in the inability to fully proceed with the reaction, but also maintain the coexistence system of beryllium vapor and beryllium melt. Compared with the reaction of metal beryllium only below the liquid surface during melting at normal pressure, negative pressure melting can generate a complete and uniform beryllium oxide product layer on the entire inner wall of the upper and lower crucibles.

[0016] In the above preparation method, preferably, in step (2), the holding time of the smelting process is controlled to be 3-6 hours, at which time the thickness of the product layer tends to be stable and no longer increases significantly with the extension of the reaction time, indicating that the beryllium oxide product layer can block the corrosion of the crucible by metallic beryllium.

[0017] In the above preparation method, preferably, in step (3), the absolute pressure of the reaction is reduced to 1-100 Pa, and the holding time is 0.2-1 h, so that the metallic beryllium is completely volatilized and escapes from the gap between the two crucibles.

[0018] In the above preparation method, preferably, in step (4), the cooling rate of the cooling process is controlled to be 1-10°C / min. The beryllium oxide product layer has weak thermal shock resistance under high temperature conditions, and its thermal expansion performance is also different from that of the base crucible. Therefore, a lower cooling rate is used in the cooling process to ensure the structural integrity of the beryllium oxide product layer.

[0019] In the above preparation method, preferably, in step (4), the cleaning is performed by mechanical cleaning or air blowing.

[0020] The invention is based on the chemical reaction between metal beryllium and metal oxide crucible material (MgO or Al2O3), and a beryllium oxide layer with uniform thickness and good mechanical properties is spontaneously formed. Specifically, two conventional metal oxide ceramic crucibles are inverted to serve as a substrate and form a reaction container. Metal beryllium is smelted under negative pressure conditions. The inner wall of the crucible is eroded by beryllium melt and beryllium vapor to form a dense beryllium oxide product layer on the surface, which can isolate the inside of the crucible from the metal beryllium and prevent the reaction from continuing. After the smelting is completed, the vacuum degree is increased to make the metal beryllium in the reaction container completely volatilize and escape from the gap between the two crucibles. The crucible is slowly cooled to room temperature, and high melting point impurities in the metal beryllium remaining in the crucible are cleaned to obtain two ceramic crucibles with beryllium oxide lining layers.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The crucible for smelting or purifying metal beryllium prepared by the present invention adopts a conventional metal oxide ceramic crucible as the base crucible. Compared with the special beryllium oxide crucible, it can achieve the same level of effect in the application field of metal beryllium smelting, and can reduce the manufacturing cost by more than 99%.

[0022] (2) Compared with the direct traditional method of preparing special beryllium oxide crucibles, the preparation method of the crucible for smelting or purifying metal beryllium of the present invention is simple in process and suitable for large-scale application. It can prepare complex and special-shaped crucibles and avoids the problems of difficult processing of beryllium oxide crucibles and toxicity of beryllium oxide dust.

[0023] (3) Compared with the traditional physical spraying method, the beryllium oxide layer of the present invention is a product protective layer generated by a pure chemical reaction process, and has the advantages of uniform thickness, few surface defects, high material utilization rate and high efficiency.

[0024] (4) In the preparation method of the present invention, the equipment used is a vacuum melting furnace, which is a common equipment in the metal beryllium smelting and purification process. No additional coating preparation equipment is required, and the equipment utilization rate is high.

[0025] (5) The crucible for smelting or purifying metal beryllium prepared by the present invention can replace beryllium oxide crucibles in the fields of metal beryllium smelting and the like, and has a broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1This is a schematic diagram of a crucible for preparing metal beryllium for smelting or purification in Example 1 of the present invention.

[0028] Figure 2 This is a scanning electron microscope photograph of the crucible and the beryllium oxide product layer after smelting metal beryllium in the alumina crucible prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0032] The purity of the metallic beryllium used in the following examples and comparative examples is 99.207%, and the impurity composition is shown in Table 1.

[0033] Table 1 Main impurities and contents in metallic beryllium

[0034] Embodiment 1: The crucible for smelting or purifying metal beryllium in this embodiment includes a magnesium oxide crucible base, and the inner wall of the magnesium oxide crucible is covered with a beryllium oxide layer with a thickness of about 66 μm.

[0035] The method for preparing a crucible for smelting or purifying metal beryllium in this embodiment comprises the following steps: (1) If Figure 1 As shown, 5.0 g of metal beryllium with the composition shown in Table 1 is placed into a magnesium oxide crucible A with an inner diameter of 2 cm and a height of 2 cm, and a magnesium oxide crucible B of the same specification is placed on top of the crucible to form a reaction vessel; (2) Place the reaction vessel consisting of two crucibles in a vacuum melting furnace, control the absolute pressure in the furnace to 3000 Pa, heat to 1600°C and melt for 3 hours; (3) Reduce the absolute pressure in the vacuum melting furnace to 10 Pa and keep it warm for 0.5 h, so that the metallic beryllium in the reaction vessel can be completely volatilized and escape from the gap between the two crucibles; (4) The reaction vessel is cooled down to room temperature at a rate of 5°C / min. The high melting point impurities in the residual beryllium metal in the crucible are purged with an air compressor to obtain two ceramic crucibles with inner walls covered with a beryllium oxide layer. The ceramic crucible can be used for smelting or purification of beryllium metal.

[0036] A smooth beryllium oxide layer was formed on the inner wall of the two crucibles, and the beryllium oxide layer did not crack or fall off, and there was no sign of corrosion by metal beryllium inside the crucible. One of the crucibles was cut longitudinally, and the thickness of the beryllium oxide product layer was measured by scanning electron microscopy to be about 66μm. 5.0g of metal beryllium with the composition shown in Table 1 was placed in another crucible, and a vacuum melting furnace was used under an argon atmosphere at normal pressure, the melting temperature was controlled to be 1400℃, and the melting was performed for 2h. After the melting was completed, the Mg content in the purified metal beryllium changed from 0.328wt% to 0.005wt%, and the Be purity changed from 99.207% to 99.527%.

[0037] Embodiment 2: The crucible for smelting or purifying metal beryllium in this embodiment includes a magnesium oxide crucible base, and the inner wall of the magnesium oxide crucible is covered with a beryllium oxide layer with a thickness of about 69 μm.

[0038] The method for preparing a crucible for smelting or purifying metal beryllium in this embodiment comprises the following steps: (1) If Figure 1 As shown, 5.0 g of metal beryllium with the composition shown in Table 1 is placed into a magnesium oxide crucible A with an inner diameter of 2 cm and a height of 2 cm, and a magnesium oxide crucible B of the same specification is placed on top of the crucible to form a reaction vessel; (2) Place the reaction vessel consisting of two crucibles in a vacuum melting furnace, control the absolute pressure in the furnace to 3000 Pa, heat to 1600°C and melt for 6 hours; (3) Reduce the absolute pressure in the vacuum melting furnace to 100 Pa and keep it warm for 1 hour to allow the metallic beryllium in the reaction vessel to completely volatilize and escape from the gap between the two crucibles; (4) The reaction vessel is cooled down to room temperature at a rate of 10°C / min. The high melting point impurities in the residual metal beryllium in the crucible are purged with an air compressor to obtain two ceramic crucibles with inner walls covered with a beryllium oxide layer. The ceramic crucible can be used for smelting or purification of metal beryllium.

[0039] A smooth beryllium oxide layer was formed on the inner wall of the two crucibles, and the beryllium oxide layer did not crack or fall off, and there was no sign of corrosion by metal beryllium inside the crucible. One of the crucibles was cut longitudinally, and the thickness of the beryllium oxide product layer was measured by scanning electron microscopy to be about 69μm. 5.0g of metal beryllium with the composition shown in Table 1 was placed in another crucible, and a vacuum melting furnace was used under an argon atmosphere at normal pressure, the melting temperature was controlled to be 1400℃, and the melting was performed for 2h. After the melting was completed, the Mg content in the purified metal beryllium changed from 0.328wt% to 0.004wt%, and the Be purity changed from 99.207% to 99.591%.

[0040] Embodiment 3: The crucible for smelting or purifying metal beryllium in this embodiment includes a magnesium oxide crucible base, and the inner wall of the magnesium oxide crucible is covered with a beryllium oxide layer with a thickness of about 49 μm.

[0041] The method for preparing a crucible for smelting or purifying metal beryllium in this embodiment comprises the following steps: (1) If Figure 1 As shown, 5.0 g of metal beryllium with the composition shown in Table 1 is placed into a magnesium oxide crucible A with an inner diameter of 2 cm and a height of 2 cm, and a magnesium oxide crucible B of the same specification is placed on top of the crucible to form a reaction vessel; (2) placing the reaction vessel consisting of two crucibles in a vacuum melting furnace, controlling the absolute pressure to 300 Pa, heating to 1350°C and melting for 5 hours; (3) Reduce the absolute pressure in the vacuum melting furnace to 10 Pa and keep it warm for 0.2 h, so that the metallic beryllium in the reaction vessel can be completely volatilized and escape from the gap between the two crucibles; (4) The reaction vessel is cooled down to room temperature at a rate of 1°C / min. The high melting point impurities in the residual metal beryllium in the crucible are purged with an air compressor to obtain two ceramic crucibles with inner walls covered with a beryllium oxide layer. The ceramic crucible can be used for smelting or purification of metal beryllium.

[0042] A smooth beryllium oxide layer was formed on the inner wall of the two crucibles, and the beryllium oxide layer did not crack or fall off, and there was no sign of corrosion by metal beryllium inside the crucible. One of the crucibles was cut longitudinally, and the thickness of the beryllium oxide product layer was measured by scanning electron microscopy to be about 49μm. 5.0g of metal beryllium with the composition shown in Table 1 was placed in another crucible, and a vacuum melting furnace was used under an argon atmosphere at normal pressure, the melting temperature was controlled to be 1400℃, and the melting was performed for 2h. After the melting was completed, the Mg content in the purified metal beryllium changed from 0.328wt% to 0.007wt%, and the Be purity changed from 99.207% to 99.573%.

[0043] Embodiment 4: The crucible for smelting or purifying metal beryllium in this embodiment includes an alumina crucible base, and the inner wall of the magnesium oxide crucible is covered with a beryllium oxide layer with a thickness of about 57 μm.

[0044] The method for preparing a crucible for smelting or purifying metal beryllium in this embodiment comprises the following steps: (1) If Figure 1 As shown, 5.0 g of metal beryllium with the composition shown in Table 1 is placed into an alumina crucible A with an inner diameter of 2 cm and a height of 2 cm, and an alumina crucible B of the same specification is placed on top of the crucible to form a reaction vessel; (2) Place the reaction vessel consisting of two crucibles in a vacuum melting furnace, control the absolute pressure to 300 Pa, heat to 1500°C and melt for 4 hours; (3) Reduce the absolute pressure in the vacuum melting furnace to 20 Pa and keep it warm for 0.5 h, so that the metallic beryllium in the reaction vessel can be completely volatilized and escape from the gap between the two crucibles; (4) The reaction vessel is cooled down to room temperature at a rate of 5°C / min. The high melting point impurities in the residual beryllium metal in the crucible are purged with an air compressor to obtain two ceramic crucibles with inner walls covered with a beryllium oxide layer. The ceramic crucible can be used for smelting or purification of beryllium metal.

[0045] The inner walls of the two crucibles have a smooth beryllium oxide layer that has not cracked or fallen off, and there is no sign of metal beryllium corrosion inside the crucibles. Take one of the crucibles and cut it vertically. Figure 2 As shown, the thickness of the beryllium oxide product layer measured by scanning electron microscope is about 57μm. 5.0g of metal beryllium with the composition shown in Table 1 was placed in another crucible, and the melting temperature was controlled to be 1400℃ in a vacuum melting furnace under normal pressure argon atmosphere for 2h. After the melting, the Al content in the purified metal beryllium changed from 0.085wt% to 0.082wt%, the Mg content changed from 0.328wt% to 0.005wt%, and the Be purity changed from 99.207% to 99.512%.

[0046] Comparative Example 1: In this embodiment, a beryllium oxide crucible is used to melt metal beryllium, and the specific process is as follows: 5.0 g of metallic beryllium with the composition shown in Table 1 was placed in a beryllium oxide crucible with an inner diameter of 2 cm and a height of 2 cm. A vacuum melting furnace was used under an argon atmosphere at normal pressure to control the melting temperature to 1400°C for 2 hours. After the melting was completed, the Mg content in the purified metallic beryllium was tested to change from 0.328wt% to 0.004wt%, the Al content to 0.085wt% to 0.075wt%, and the Be purity to 99.207% to 99.593%.

[0047] Compared with the embodiment, this comparative example uses a beryllium oxide crucible to melt metal beryllium. The results of testing the chemical composition of metal beryllium through the embodiment and comparative example 1 show that the magnesium oxide or aluminum oxide crucible with a beryllium oxide layer on the inner wall prepared by the present invention can play the same level of effect as the beryllium oxide crucible in the application of metal beryllium melting. The reduction of Mg content in the metal beryllium of the embodiment is caused by the volatilization of Mg under the temperature condition of 1400°C, while the Al content before and after melting is almost unchanged, indicating that the metal beryllium will not be contaminated by the metal elements of the crucible during the melting process.

[0048] Comparative Example 2: The method for preparing a crucible for smelting or purifying metal beryllium in this comparative example comprises the following steps: (1) 5.0 g of metallic beryllium having the composition shown in Table 1 was placed in a magnesium oxide crucible having an inner diameter of 2 cm and a height of 2 cm, and a magnesium oxide crucible of the same specification was placed on top of the crucible to form a reaction vessel; (2) placing the reaction vessel consisting of two crucibles in a vacuum melting furnace, heating to 1600°C and melting for 3 hours under normal pressure argon atmosphere; (3) Evacuate the vacuum melting furnace to 5000 Pa and keep it warm for 0.1 h to volatilize the metallic beryllium in the reaction vessel; (4) The temperature was controlled to drop to room temperature at a rate of 5°C / min, and the residual metallic beryllium and high-melting-point impurities in the crucible were purged with an air compressor. It was observed that the beryllium oxide product layer was only distributed in the area below the liquid surface after the metallic beryllium in the lower crucible melted, and part of the metallic beryllium did not volatilize and remained in the lower crucible, causing the beryllium oxide product layer to fall off during cleaning.

[0049] The crucible was cut longitudinally and the thickness of the beryllium oxide product layer was measured by scanning electron microscopy to be approximately 64 μm.

[0050] Compared with Example 1, under normal pressure conditions, the distribution area of ​​the beryllium oxide product layer is small. If a uniform and complete beryllium oxide lining layer is to be obtained, a large amount of metallic beryllium is required. The vacuum degree and the insulation time in step (3) are insufficient, and metallic beryllium remains in the lower crucible. When cleaning, the structural integrity of the beryllium oxide product layer is easily damaged to a certain extent.

[0051] Comparative Example 3: The method for preparing a crucible for smelting or purifying metal beryllium in this comparative example comprises the following steps: (1) 5.0 g of metallic beryllium having the composition shown in Table 1 was placed into a magnesium oxide crucible having an inner diameter of 2 cm and a height of 2 cm, and a magnesium oxide crucible of the same specification was placed on top of the crucible to form a reaction vessel; (2) Place the reaction vessel consisting of two crucibles in a vacuum melting furnace, control the absolute pressure to 300 Pa, heat to 1600°C and melt for 1 hour; (3) The absolute pressure in the vacuum melting furnace is reduced to 20 Pa and kept at this temperature for 0.4 h, so that the metallic beryllium in the reaction vessel is completely volatilized and escapes from the gap between the two crucibles; (4) The temperature was controlled to drop to room temperature at a rate of 20°C / min, and the high-melting-point impurities in the residual metallic beryllium in the crucible were blown away by an air compressor. It was observed that a beryllium oxide product layer was generated on the inner wall of the two crucibles. There was no sign of metallic beryllium corrosion inside the crucibles, but the product layer showed local cracking and shedding. The crucible was cut longitudinally, and the thickness of the beryllium oxide product layer was measured by scanning electron microscopy to be approximately 51 μm.

[0052] Compared with Example 1, the smelting holding time in step (2) of this comparative example is too short, the thickness of the beryllium oxide product layer has not reached stability, and the inside of the crucible cannot be well protected from corrosion by the metal beryllium during the smelting or purification of the metal beryllium. The cooling rate in step (4) is too fast, resulting in cracking and shedding of the generated beryllium oxide product layer.

Claims

1. A crucible for smelting or purifying metal beryllium, characterized in that: The invention comprises a metal oxide ceramic crucible substrate, the inner wall of which is covered with a beryllium oxide layer.

2. The crucible for smelting or purifying metal beryllium according to claim 1, characterized in that: The beryllium oxide layer has a thickness of 40-100 μm.

3. The crucible for smelting or purifying metal beryllium according to claim 1, characterized in that: The metal oxide ceramic crucible substrate comprises one of an aluminum oxide crucible and a magnesium oxide crucible.

4. A method for preparing a crucible for smelting or purifying metal beryllium, characterized in that: The following steps are involved: (1) Take two metal oxide ceramic crucibles of the same specifications as the base, place one of the crucibles at the bottom and put metal beryllium in it, and then put the other crucible upside down at the top to form a reaction vessel; (2) placing the reaction vessel consisting of the two crucibles in step (1) in a vacuum melting furnace, heating it to a temperature above the melting point of beryllium under negative pressure conditions for melting, and reacting the inner wall of the crucible with the metal beryllium to form a beryllium oxide layer on the inner wall of the crucible; (3) Lowering the absolute pressure of the vacuum melting furnace and maintaining the temperature, so that the metallic beryllium in the reaction vessel can be completely volatilized and escaped from the gap between the two crucibles; (4) After cooling to room temperature and cleaning the high melting point impurities in the metallic beryllium remaining in the crucible, a ceramic crucible with an inner wall covered with a beryllium oxide layer is obtained.

5. The preparation method according to claim 4, characterized in that: In step (1), the amount of metal beryllium added is Obtained through the following calculation formula: in, m Be is the amount of metallic beryllium added, in g; M Be and M BeO are the relative molar masses of Be and BeO, 9 g / mol and 25 g / mol, respectively; ρ is the density of BeO, 3.01 g / cm 3 ; S is the surface area of ​​the reactor inner wall, in cm 2 ; h is the thickness of the beryllium oxide product layer generated during the smelting process, in cm; N For calculation constant, the value range is 20-50.

6. The preparation method according to claim 4, characterized in that: In step (2), the smelting temperature is controlled to be 1350-1600°C, and the absolute pressure during the smelting process is 300-3000Pa.

7. The preparation method according to claim 4, characterized in that: In step (2), the holding time of the smelting process is controlled to be 3-6 hours.

8. The preparation method according to claim 4, characterized in that: In step (3), the absolute pressure of the reaction is reduced to 1-100 Pa, and the insulation time is 0.2-1 h.

9. The preparation method according to claim 4, characterized in that: In step (4), the cooling rate of the cooling process is controlled to be 1-10°C / min.

10. The preparation method according to claim 4, characterized in that: In step (4), the cleaning is performed by mechanical cleaning or air blowing.

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