Amorphous alloy catalyst, preparation method and application thereof

Abstract

The application discloses an amorphous alloy catalyst, a preparation method and application thereof, and the amorphous alloy catalyst comprises a transition metal element and a metalloid element; the transition metal element is at least one selected from ruthenium, platinum, palladium, iron, cobalt or nickel; and the metalloid element is at least one selected from boron or phosphorus. The method is simple and easy to operate, can easily prepare the amorphous alloy catalyst, and exhibits excellent catalytic activity in N-ethylcarbazole hydrogenation reaction.

Description

TECHNICAL FIELD

[0001] The present application relates to an amorphous alloy catalyst, a preparation method and application thereof, and belongs to the field of catalysis technology. BACKGROUND

[0002] Compared with crystals, amorphous alloys have unique electronic and structural properties (Brower W E, et al. Nature, 1983, 301(5900), 497-499), and the composition and electronic properties can be adjusted in a wide range, showing excellent catalytic activity and high selectivity in some reactions. Baiker et al. summarized some characteristics of amorphous alloys (Baiker A. Faraday Discuss., 1989, 87(0), 239-251), which showed that they could be used as high-performance catalytic materials:

[0003] 1) The composition and electronic properties of amorphous alloys can be adjusted in a wide range, which changes their catalytic performance and enables them to adapt to different activity and selectivity requirements;

[0004] 2) The isotropic and uniform structure of amorphous alloys enables the uniform distribution of active sites in the same chemical environment, which is conducive to the development of high-selectivity catalysts;

[0005] 3) The long-range disorder of amorphous alloys enables them to have a high density of coordination unsaturated sites, similar to the low-coordination number ladder sites and kink sites in crystal catalysts, which are considered to be the active sites in many reactions.

[0006] Amorphous alloys are usually prepared by chemical reduction method using reducing agents such as borohydride (BH 4- ) or hypophosphite (H2PO 2-Reduction of metal salts in aqueous solution can also produce amorphous metal boride or phosphide alloy particles (Klement W, et al. Nature, 1960, 187(4740), 869-870). However, due to the violent exothermic reduction process, the prepared amorphous alloy catalysts usually have strong aggregation and reduced catalyst activity. Liaw et al. used water-soluble polyvinylpyrrolidone (PVP) as a protective agent when preparing Ni-B catalyst (PVP-NiB), and the PVP polymer was adsorbed on the NiB nanoparticles through weak coordination bonds to stabilize them (Liaw B-J, et al. APPL CATAL A-GEN, 2005, 284(1), 239-246). The team later prepared a surfactant-stabilized Ni-B catalyst (ME-NiB) in a ternary microemulsion system. Surfactant molecules can stabilize and limit particle growth (Chiang S-J, et al. APPL CATAL A-GEN, 2007, 319, 144-152). Li et al. synthesized Ru-B nanoparticles by chemical reduction method and used ultrasonic wave for assistance, and adjusting the ultrasonic power and time could control the particle size (Li H, et al. Chinese J. Chem., 2006, 24(5), 613-619).

[0007] In the existing synthesis methods, complex synthesis steps or the introduction of protective agent components that are difficult to completely remove are usually required, which is not conducive to the large-scale application of amorphous alloys. Therefore, it is of great significance to optimize the traditional synthesis method or develop a simple preparation procedure to realize the synthesis of highly dispersed and ultra-fine amorphous alloy catalysts. SUMMARY

[0008] According to one aspect of the present application, a preparation method of an amorphous alloy catalyst is provided, comprising solid-phase ball milling of raw materials containing a transition metal precursor and a reducing agent, water washing, stirring, to obtain an amorphous alloy catalyst; the transition metal precursor is a chloride of a transition metal element;

[0009] The reducing agent is a compound containing a metalloid element.

[0010] Optionally, the preparation method comprises at least the following steps:

[0011] (1) mixing the transition metal precursor and the reducing agent to obtain a mixture I;

[0012] (2) solid-phase ball milling of the mixture I to obtain a mixture II;

[0013] (3) adding the mixture II into water, stirring, to obtain an amorphous alloy catalyst.

[0014] Optionally, the transition metal element is selected from at least one of ruthenium, platinum, palladium, iron, cobalt or nickel; and the metalloid element is selected from at least one of boron or phosphorus.

[0015] Optionally, the reducing agent is selected from at least one of sodium borohydride or sodium hypophosphite.

[0016] Optionally, the molar ratio of the transition metal precursor to the reducing agent is 1:3-7.

[0017] Optionally, the solid phase ball milling is performed at a ball milling speed of 200-500 rpm / min, a single ball milling time of 2-4 hours, and a ball milling number of 2-4 times.

[0018] Optionally, the ball milling speed is selected from any value of 200 rpm / min, 300 rpm / min, 400 rpm / min, 500 rpm / min, or any value between any two of the above values.

[0019] Optionally, the single ball milling time is selected from any value of 2 hours, 3 hours, 4 hours, or any value between any two of the above values.

[0020] Optionally, the ball milling number is selected from any value of 2 times, 3 times, 4 times, or any value between any two of the above values.

[0021] Optionally, the stirring time is 4-8 hours.

[0022] Optionally, the stirring time is selected from any value of 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or any value between any two of the above values.

[0023] Optionally, the solid phase ball milling comprises solid phase ball milling of the raw material and medium balls in an inert atmosphere.

[0024] Optionally, the mass ratio of the medium balls to the raw material is 90-110:1.

[0025] Optionally, the medium balls are steel balls.

[0026] Optionally, the inert atmosphere is an argon atmosphere.

[0027] Optionally, the mass ratio of the mixture II to water in step (3) is 0.1 g: 50-100 ml.

[0028] According to another aspect of the present application, there is provided an amorphous alloy catalyst, the catalyst comprising a transition metal element and a metalloid element;

[0029] The molar ratio between the transition metal element and the metalloid element is 3-5:1.

[0030] The transition metal element is selected from at least one of ruthenium, platinum, palladium, iron, cobalt or nickel;

[0031] The metalloid element is selected from at least one of boron or phosphorus.

[0032] According to yet another aspect of the present application, there is provided an application of the amorphous alloy catalyst or the amorphous alloy catalyst prepared by the above method in a hydrogenation reaction of N-ethylcarbazole.

[0033] Optionally, the raw material containing the amorphous alloy catalyst and N-ethylcarbazole is mixed with water, dried, and then subjected to the hydrogenation reaction under hydrogen.

[0034] Optionally, the molar ratio of the amorphous alloy catalyst to the N-ethylcarbazole is 1:5-30.

[0035] Optionally, the drying temperature is 25-30℃.

[0036] Optionally, the drying temperature is selected from any value among 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, or any value between any two of the above values.

[0037] The reaction conditions of the hydrogenation reaction are as follows: the reaction temperature is 25-60℃, the heating rate is 2-4℃ / min, the reaction pressure is 1-7MPa, and the reaction time is 2.5-32.5h.

[0038] Optionally, the upper limit of the reaction temperature in the hydrogenation reaction is selected from 60℃, 55℃, 50℃, 45℃, 40℃, 35℃, 30℃, 25℃; and the lower limit is selected from 60℃, 55℃, 50℃, 45℃, 40℃, 35℃, 30℃, 25℃.

[0039] Optionally, the upper limit of the reaction pressure in the hydrogenation reaction is selected from 7MPa, 5MPa, 3MPa, 1MPa; and the lower limit is selected from 7MPa, 5MPa, 3MPa, 1MPa.

[0040] Optionally, the reaction time in the hydrogenation reaction is selected from any value among 2.5h, 3h, 6h, 7h, 8h, 10h, 12h, 16h, 20h, 24h, 28h, 32.5h, or any value between any two of the above values.

[0041] The beneficial effects that can be produced by the present application include:

[0042] 1) The amorphous alloy catalyst provided by the present application has a typical amorphous structure, and the amorphous alloy catalyst is prepared by a one-pot method through solid-phase mechanical ball milling, thereby avoiding a violent exothermic reduction process in an aqueous phase reaction and simplifying the preparation process of highly dispersed amorphous alloy nanoparticles.

[0043] 2) The kind and composition of transition metal elements and metalloid elements in the amorphous alloy catalyst provided by the present application can be adjusted by changing the added metal source and metal / reducing agent ratio.

[0044] 3) The amorphous alloy catalyst provided by the present application is applied to the hydrogenation reaction of N-ethylcarbazole (NEC), and high selective hydrogenation of N-ethylcarbazole to dodecahydro-N-ethylcarbazole (12H-NEC) is achieved at room temperature. The preparation method of the amorphous alloy catalyst is simple and easy to operate, does not introduce other surfactant components, and exhibits excellent catalytic activity in the hydrogenation reaction of N-ethylcarbazole, and has potential application value. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 XRD spectrum of the RuNPs catalyst obtained in Comparative Example 1 of the present application.

[0046] Figure 2 XRD spectrum of the Ru 3.5 B catalyst obtained in Example 1 of the present application.

[0047] Figure 3 TEM spectrum of the Ru 3.5 B catalyst obtained in Example 1 of the present application.

[0048] Figure 4 SAED image of the Ru 3.5 B catalyst obtained in Example 1 of the present application.

[0049] Figure 5 XPS spectrum of Ru 3d of the Ru 3.5 B catalyst obtained in Example 1 of the present application.

[0050] Figure 6 XPS spectrum of B 1s of the Ru 3.5 B catalyst obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0051] The present application will be described in detail below with reference to examples, but the present application is not limited to these examples.

[0052] Unless otherwise specified, the raw materials in the examples of the present application are purchased through commercial channels.

[0053] The analysis method in the examples of the present application is as follows:

[0054] XRD was tested by Panalytical X'pert Pro type rotating target X-ray powder diffractometer, test conditions: Cu target Kα (λ = 0.154046 nm), tube voltage is 40 kV, tube current is 40 mA, scanning speed is 10 ° / min. TEM adopts the instrument model JEM 2100, sample preparation: add a small amount of sample into ethanol, ultrasonic dispersion, take two to three drops of the suspension liquid on the microgrid support film, and test after the ethanol volatilization. XPS adopts the instrument model ThermoFisher Scientific K-Alpha type X-ray photoelectron spectrometer, uses Al Kα ray as excitation source (hν = 1486.6 eV). The sample catalyst is first mixed with N-ethylcarbazole in deionized water by stirring, then the wet sample is obtained by centrifugation, dried under vacuum, and finally tested.

[0055] Comparative Example 1 Ru NPs catalyst

[0056] 400 mg of ruthenium chloride and 248.2 mg of sodium hydride were weighed into a ball mill jar and mixed uniformly, the molar ratio of ruthenium chloride and sodium hydride was 1:5, the ball mill jar was loaded into a planetary ball mill, and ball milling was carried out under argon atmosphere, the mass ratio of steel medium ball to mixture during ball milling was 100:1, the rotation speed during ball milling was 200 rpm / min, the ball milling time was 2 h, and the post-milling sample was obtained.

[0057] The post-milling sample was separated from the wall of the ball mill jar and re-milled for 2 h at a rotation speed of 200 rpm / min. The post-milling product was added to 60 ml of deionized water in 10 portions of 60 mg each, and stirring was continued for 4 h to obtain a suspension. The suspension was centrifuged at a rotation speed of 4000 rpm / min, the supernatant was removed, and the lower solid was preserved in deionized water to obtain the Ru NPs catalyst.

[0058] Example 1

[0059] 400 mg of ruthenium chloride and 351.8 mg of sodium borohydride were weighed into a ball mill jar and mixed uniformly, the molar ratio of ruthenium chloride and sodium borohydride was 1:5, the ball mill jar was loaded into a planetary ball mill, and ball milling was carried out under argon atmosphere, the mass ratio of steel medium ball to mixture during ball milling was 100:1, the rotation speed during ball milling was 200 rpm / min, the ball milling time was 2 h, and the post-milling sample was obtained.

[0060] After separating the ball-milled sample from the milling jar wall, it was ball-milled again for 2 hours at 200 rpm. The milled product was added in 10 portions of 60 mg to 60 ml of deionized water, and the mixture was stirred continuously for 4 hours to obtain a suspension. The suspension was centrifuged at 4000 rpm, and the supernatant was removed. The lower solid layer was stored in deionized water to obtain Ru. 3.5 B catalyst.

[0061] Test Example 1: Structural Characterization of Amorphous Alloy Catalysts

[0062] Comparison of the Ru NPs catalyst obtained in Comparative Example 1 and the Ru catalyst obtained in Example 1 3.5 Catalyst B underwent structural characterization, and the specific results are as follows:

[0063] Figure 1 The structural characteristics of the Ru NPs catalyst were determined by X-ray powder diffraction (XRD). Clear diffraction peaks corresponding to Ru crystals were observed in the XRD pattern, indicating that ruthenium chloride can be effectively reduced to Ru crystals by ball milling.

[0064] Figure 2 Ru tested by X-ray powder diffraction (XRD) 3.5 Structural characteristics of the B catalyst. The XRD pattern shows only one broad peak in the 35°–45° range, consistent with typical amorphous structure characteristic peaks, indicating that Ru... 3.5 B is an amorphous alloy. Figure 3 For Ru 3.5 Transmission electron microscopy (TEM) images of catalyst B, from Figure 3 It can be seen from Ru 3.5 Catalyst B consists of relatively uniformly distributed nanoparticles with an average particle size of approximately 5 nm. Figure 4 For Ru 3.5 Selected area electron diffraction (SAED) image of catalyst B, Ru 3.5 The SAED image of catalyst B shows diffraction rings, indicating that the sample has a long-range disordered structure, further suggesting that Ru 3.5 Catalyst B is an amorphous alloy.

[0065] Example 2: Application of Ru NPs catalyst in the hydrogenation reaction of N-ethylcarbazole

[0066] 40 mg of the RuNPs catalyst obtained in Comparative Example 1 was mixed thoroughly with 50 ml of deionized water. Then, 386.6 mg of N-ethylcarbazole was added to the solution to make the molar ratio of RuNPs to N-ethylcarbazole 1:5. After stirring and mixing thoroughly, the solid was collected by centrifugation and dried under vacuum at 30 °C to obtain a dry solid. The dry solid was then loaded into a reaction tube and heated to the reaction temperature of 60 °C at a heating rate of 3 °C / min. Hydrogen gas (purity 99.999%) was then introduced, and the reaction pressure was maintained at 7 MPa. After reacting for 8 h, the hydrogenation product was collected and designated as Sample 1#. Sample 1# was dissolved in ethanol and analyzed by gas chromatography (Agilent 7890-B, HP-5 column) to determine the conversion rate. The NEC conversion rate was 58.1%, and the yield of dodecahydro-N-ethylcarbazole (12H-NEC) was 23.3%.

[0067] Example 3 Ru 3.5 Application of catalyst B in the N-ethylcarbazole reaction.

[0068] 40 mg of Ru obtained in Example 1 3.5 Catalyst B and 50 ml of deionized water were mixed thoroughly. Then, 386.6 mg of N-ethylcarbazole was added to the above solution to make Ru 3.5 The molar ratio of B to N-ethylcarbazole was 1:5. After thorough mixing, the solid was collected by centrifugation and dried under vacuum at 30°C to obtain a dry solid. The dried solid was then loaded into a reaction tube and heated to the reaction temperature of 60°C at a heating rate of 3°C / min. Hydrogen gas (purity 99.999%) was then introduced, and the reaction pressure was maintained at 7 MPa. Pressure changes in the reaction tube were recorded using a pressure sensor. The reaction was considered complete when the pressure stabilized and did not decrease. The reaction time was recorded, and the hydrogenation product was collected and designated as sample 2#. Sample 2# was dissolved in ethanol and analyzed by gas chromatography (Agilent 7890-B, HP-5 column) to determine the conversion rate. The NEC conversion rate was 100%, and the yield of dodecahydro-N-ethylcarbazole (12H-NEC) was 99.3%.

[0069] Example 4

[0070] Preparation of Sample 3#: The preparation process differs from that of Sample 2# in that the reaction pressure is 5 MPa and the reaction time is 3 h, hence it is designated as Sample 3#. Sample 3# was dissolved in ethanol and then analyzed by gas chromatography (Agilent 7890-B, HP-5 column) to determine the conversion rate. The NEC conversion rate was 100%, and the 12H-NEC yield was 93.7%.

[0071] Example 5

[0072] Preparation of sample 4#: The difference between the preparation process of sample 4# and sample 2# is that the reaction pressure is 3 MPa and the reaction time is 8 h, which is recorded as sample 4#. After sample 4# is dissolved in ethanol, it is detected by gas chromatography (chromatograph model Agilent 7890-B, chromatographic column HP-5) to determine the conversion rate, the NEC conversion rate is 100%, and the 12H-NEC yield is 99.6%.

[0073] Example 6

[0074] Preparation of sample 5#: The difference between the preparation process of sample 5# and sample 2# is that the reaction pressure is 1 MPa and the reaction time is 32.5 h, which is recorded as sample 5#. After sample 5# is dissolved in ethanol, it is detected by gas chromatography (chromatograph model Agilent 7890-B, chromatographic column HP-5) to determine the conversion rate, the NEC conversion rate is 100%, and the 12H-NEC yield is 92.7%.

[0075] Example 7

[0076] Preparation of sample 6#: The difference between the preparation process of sample 6# and sample 2# is that the reaction temperature is 35°C, the reaction pressure is 7 MPa, and the reaction time is 6 h, which is recorded as sample 6#. After sample 6# is dissolved in ethanol, it is detected by gas chromatography (chromatograph model Agilent 7890-B, chromatographic column HP-5) to determine the conversion rate, the NEC conversion rate is 100%, and the 12H-NEC yield is 98.6%.

[0077] Example 8

[0078] Preparation of sample 7#: The difference between the preparation process of sample 7# and sample 2# is that the reaction temperature is 25°C, the reaction pressure is 7 MPa, and the reaction time is 24 h, which is recorded as sample 7#. After sample 7# is dissolved in ethanol, it is detected by gas chromatography (chromatograph model Agilent 7890-B, chromatographic column HP-5) to determine the conversion rate, the NEC conversion rate is 100%, and the 12H-NEC yield is 98.6%.

[0079] Example 9

[0080] Preparation of sample 8#: The difference between the preparation process of sample 8# and sample 2# is that 20 mg of Ru 3.5 B catalyst, 50 ml of deionized water is uniformly mixed, and then 386.6 mg of N-ethylcarbazole is added to the above solution, so that the molar ratio of Ru 3.5 B to N-ethylcarbazole is 1:10, and the reaction time is 7 h, which is recorded as sample 8#. After sample 8# is dissolved in ethanol, it is detected by gas chromatography (chromatograph model Agilent 7890-B, chromatographic column HP-5) to determine the conversion rate, the NEC conversion rate is 100%, and the 12H-NEC yield is 99.2%.

[0081] Table 1: Catalytic activity of catalysts in NEC hydrogenation reaction

[0082]

[0083] Note: The molar ratio of Ru to substrate refers to the molar ratio of Ru to N- ethylcarbazole.

[0084] The catalysts provided in the examples were applied to the N-ethylcarbazole (NEC) hydrogenation reaction, and the hydrogenation product was detected by gas chromatography (chromatograph model Agilent 7890-B, chromatographic column HP-5) after being dissolved in ethanol to determine the conversion rate.

[0085] The activity test results are shown in Table 1, Ru 3.5 The B catalyst achieved complete conversion of NEC in 2.5 h under the reaction conditions of 60°C and 7 MPa H2, and the yield of dodecahydro-N- ethylcarbazole (12H-NEC) was 99.3%. When the reaction temperature was fixed at 60°C, the reaction pressure was adjusted to 3 MPa H2, and the NEC hydrogenation reaction ended in 8 h, and the yield of 12H-NEC was 99.6%. When the reaction pressure was 1 MPa H2, the reaction was carried out for 32.5 h, and the yield of 12H-NEC was 92.7%. When the reaction conditions were 25°C and 7 MPa H2, the NEC was completely converted after 24 h, and the yield of 12H-NEC was 98.6%, indicating that the Ru 3.5 The B catalyst can achieve high selective hydrogenation of NEC.

[0086] When the molar ratio of Ru to substrate was reduced from 1:5 to 1:10, the yield of 12H-NEC was 99.2% in 7 hours under the reaction conditions of 60°C and 7 MPa H2. The above activity test results show that the Ru 3.5 The B catalyst still exhibits excellent NEC hydrogenation activity at room temperature or low pressure, and the product is mainly 12H-NEC.

[0087] Test Example 2 Ru 3.5 The B catalyst was mixed with N-ethylcarbazole and the dried sample was characterized.

[0088] Since the amorphous alloy may agglomerate during direct drying, N- ethylcarbazole was used for dispersion, and the dispersed sample was characterized, and the specific results are as follows: Figure 5 The XPS spectrum of Ru 3d of the B catalyst, the Ru 3.5 The XPS spectrum of Ru 3d of the B catalyst, the Ru 3.5Catalyst B was mixed with N-ethylcarbazole, dried, and then tested. The XPS spectrum of Ru 3d was fitted, and corrected using the binding energy of contaminated C (284.8 eV). The C1s signal at 283.9 eV can be attributed to the C atom in NEC. The signals at 286.6 eV and 281.1 eV are attributed to RuO, respectively. x Ru 3d 3 / 2 and Ru 3d 5 / 2 The peak at 280.0 eV is similar to the Ru peak reported in the literature. 0 The consistent binding energy positions indicate the presence of metallic Ru species in the catalyst. A relatively obvious peak is observed at 279.6 eV, lower than that of Ru. 0 The binding energy of the species indicates the presence of electron-rich Ru species in the catalyst. Figure 6 For Ru 3.5 XPS spectra of B1s of catalyst B. Figure 6 Two distinct peaks were observed, located at approximately 190.9 eV and 187.9 eV, respectively. These can be attributed to the binding energies of the oxidized and elemental B states, respectively. Compared to the reported binding energy of pure B (187.1 eV), the binding energy of elemental B shows a significant positive binding energy shift, indicating that B transfers electrons to Ru in the catalyst, resulting in electron-deficient B and electron-rich Ru species.

[0089] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. Use of an amorphous alloy catalyst in the hydrogenation reaction of N-ethylcarbazole, characterized in that, The raw material containing amorphous alloy catalyst and N-ethyl carbazole is mixed with water, dried, and subjected to hydrogenation reaction under hydrogen condition; The molar ratio of the amorphous alloy catalyst to the N-ethyl carbazole is 1:5-30, and the molar amount of the amorphous alloy catalyst is calculated based on Ru element; The reaction conditions of the hydrogenation reaction are as follows: the reaction temperature is 25-60°C, the heating rate is 2-4°C / min, the reaction pressure is 1-7 MPa, and the reaction time is 2.5-32.5 h; The amorphous alloy catalyst comprises a transition metal element and a metalloid element; The molar ratio between the transition metal element and the metalloid element is 3-5:1; The preparation method of the amorphous alloy catalyst comprises the following steps: solid-phase ball milling of raw materials containing a transition metal precursor and a reducing agent, water washing, and stirring to obtain the amorphous alloy catalyst; The transition metal precursor is a chloride of a transition metal element; The reducing agent is a compound containing a metalloid element; The transition metal element is selected from at least one of ruthenium, platinum, palladium, iron, cobalt, or nickel; The metalloid element is selected from at least one of boron or phosphorus.

2. Use according to claim 1, characterized in that, The method comprises the following steps: (1) mixing a transition metal precursor and a reducing agent to obtain a mixture I; (2) solid-phase ball milling of the mixture I to obtain a mixture II; (3) adding the mixture II into water and stirring to obtain an amorphous alloy catalyst.

3. Use according to claim 1, characterized in that, The reducing agent is selected from at least one of sodium borohydride or sodium hypophosphite.

4. Use according to claim 1, characterized in that, The molar ratio of the transition metal precursor to the reducing agent is 1:3-7.

5. The use according to claim 1, characterized in that, The solid-phase ball milling conditions are as follows: the ball milling rotation speed is 200-500 rpm / min, the single ball milling time is 2-4 h, and the ball milling times are 2-4 times.

6. The use according to claim 1, characterized in that, The stirring time is 4-8 h.

7. The use according to claim 1, characterized in that, The solid-phase ball milling comprises solid-phase ball milling of the raw materials and medium balls in an inactive atmosphere.

8. Use according to claim 7, characterized in that, The mass ratio of the medium balls to the raw materials is 90-110:

1.

9. Use according to claim 7, characterized in that, The medium balls are steel balls.

10. Use according to claim 7, characterized in that, The inactive atmosphere is an argon atmosphere.

11. Use according to claim 2, characterized in that, In step (3), the mass-volume ratio of the mixture II to water is 0.1 g:50-100 ml.

12. The use according to claim 1, characterized in that, The drying temperature is 25-35°C.

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