Preparation method of high-purity silicon carbide powder

Abstract

The invention relates to the technical field of silicon carbide production, in particular to a preparation method of high-purity silicon carbide powder. According to the preparation method of the high-purity silicon carbide powder, a silicon material is added into a carbon-containing solution, ball milling and drying are carried out, a first material is obtained, and the carbon material is selected from any one of corn starch and wheat starch; then putting the obtained first material into a tubular furnace and calcining in sections to obtain a second material; placing the second material in a reaction furnace, introducing a carbon source gas, and reacting to obtain a third material after the reaction is finished; and finally, washing the obtained third material with hydrofluoric acid and deionized water respectively, and drying to obtain the high-purity silicon carbide powder. The prepared high-purity silicon carbide powder is low in impurity content, high in purity and excellent in particle distribution, and the quality of the high-purity silicon carbide powder is effectively guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide production, and in particular to a method for preparing high-purity silicon carbide powder. Background Art

[0002] Silicon carbide is an inorganic substance with the chemical formula SiC. Silicon carbide is a semiconductor that exists in nature in the form of the extremely rare mineral moissanite. Since 1893, it has been mass-produced as powders and crystals for use as abrasives, etc. With the emergence of the third-generation semiconductors under the influence of the times, the application of silicon carbide in all aspects is in the ascendant. With the development of 5G communications, new energy vehicles, and new energy photovoltaics, the demand for silicon carbide has increased significantly. Silicon carbide has been widely used in the manufacture of semiconductor devices under extreme conditions such as high temperature, high pressure, and high frequency due to its wide band gap, corrosion resistance, high hardness, high pressure resistance, high temperature resistance, high frequency, and radiation resistance. In addition, because silicon carbide has very high chemical inertness, it is often used as a carrier for catalysis and catalysts. It has broad application prospects in photocatalytic degradation of pollutants and advanced oxidation.

[0003] In the patent document with publication number "CN103508454B" and titled "A method for preparing high-purity silicon carbide raw materials", it is recorded that "the method includes the following steps: providing high-purity silicon powder and high-purity carbon powder; the high-purity silicon powder and high-purity carbon powder are fully mixed and placed in a crucible, and a primary silicon carbide material is formed in a high-temperature furnace of 1400-2200°C; the primary silicon carbide material is crushed and subjected to high-temperature oxidation at 600-1400°C in an oxidation furnace to form a secondary silicon carbide material; the secondary silicon carbide material is subjected to high-temperature vacuum degassing at 800-1600°C in a high vacuum furnace to form a tertiary silicon carbide material; the tertiary silicon carbide material is subjected to wet chemical metallurgical treatment to obtain a high-purity silicon carbide raw material".

[0004] Although the high-purity silicon carbide powder prepared by the above patent document has the advantages of high purity, the process is cumbersome, and the hydrometallurgical process is highly polluting, which increases the production cost. At the same time, the silicon carbide powder is easy to agglomerate after being dried by the hydrometallurgical process. If the agglomerated silicon carbide powder is crushed by a crushing process, new impurities are easily introduced, and further improvement is still needed. Based on this, the present invention provides a method for preparing high-purity silicon carbide powder to solve the above-mentioned technical problems! Summary of the invention

[0005] The object of the present invention is to provide a method for preparing high-purity silicon carbide powder. The prepared high-purity silicon carbide powder not only has low impurity content and high purity, but also has excellent particle distribution, effectively ensuring its quality.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing high-purity silicon carbide powder, comprising the following steps:

[0008] S1, adding silicon material to the carbon-containing solution, and obtaining a first material after ball milling and drying;

[0009] S2, placing the obtained first material in a tubular furnace and calcining in stages to obtain a second material;

[0010] S3, placing the second material in a reactor and introducing a carbon source gas to react, and after the reaction is completed, obtaining a third material;

[0011] S4. Wash the obtained third material with hydrofluoric acid and deionized water for 2 to 4 times respectively, and then dry it to obtain high-purity silicon carbide powder.

[0012] The present invention is further configured as follows: in the step S1, the carbon-containing solution is prepared by mixing carbon material and deionized water at a solid-liquid ratio of 0.02 to 0.2 g / mL.

[0013] The present invention is further configured as follows: the carbon material is selected from any one of corn starch and wheat starch.

[0014] The present invention is further configured as follows: in step S1, the silicon material is high-purity silicon powder, and the added amount of the silicon material is 2.4-4.4% of the mass of the carbon-containing solution.

[0015] The present invention is further configured as follows: in the step S1, the ball-to-material ratio of the ball milling is 30-35:1, the ball diameter is 3-5 mm, the ball milling time is 120-140 min, the drying temperature is 90-100° C., and the drying time is 24-26 h.

[0016] The present invention is further configured as follows: in step S2, the process of the staged calcination is as follows:

[0017] The first stage: heating to 620-630°C at a heating rate of 10-12°C / min in a nitrogen atmosphere and keeping the temperature for 130-140 minutes;

[0018] The second stage: in a nitrogen atmosphere, the temperature is raised to 1200-1300°C at a heating rate of 4-7°C / min, and the temperature is kept for 130-140 minutes;

[0019] The third stage: in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 1 to 3°C / min and kept at this temperature for 60 to 80 minutes.

[0020] The present invention is further configured as follows: in step S3, the carbon source gas is selected from any one of propane, ethane and butane.

[0021] The present invention is further configured as follows: in step S3, the flow rate of the carbon source gas is 10 to 100 sccm.

[0022] The present invention is further configured as follows: in step S3, the pressure of the reaction furnace is 200-320 Pa.

[0023] The present invention is further configured as follows: in the step S3, the reaction temperature is 2150-2200°C.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention adds silicon material to a carbon-containing solution, and after ball milling and drying, obtains a first material, wherein the carbon material is selected from any one of corn starch and wheat starch; then the obtained first material is placed in a tubular furnace for staged calcination to obtain a second material; then the second material is placed in a reactor and a carbon source gas is introduced for reaction, and after the reaction is completed, a third material is obtained; finally, the obtained third material is washed with hydrofluoric acid and deionized water respectively, and after drying, a high-purity silicon carbide powder is obtained. The high-purity silicon carbide powder prepared by the present invention not only has a low impurity content and high purity, but also has an excellent particle distribution, which effectively guarantees its quality. The preparation method of the high-purity silicon carbide powder provided by the present invention has a broader market prospect and is more suitable for promotion. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment provides a method for preparing high-purity silicon carbide powder, comprising the following steps:

[0029] S1. Add silicon material to the carbon-containing solution, and obtain the first material after ball milling and drying.

[0030] The carbon-containing solution is prepared by mixing carbon material and deionized water at a solid-liquid ratio of 0.02 g / mL.

[0031] Furthermore, the carbon material is corn starch.

[0032] In this embodiment, it should be noted that corn starch was purchased from Chuzhou Xinfa Food Co., Ltd.

[0033] In addition, the silicon material is high-purity silicon powder, and the added amount of the silicon material is 2.4% of the mass of the carbon-containing solution.

[0034] In this embodiment, it should be noted that it was purchased from Kairui New Materials (Beijing) Technology Co., Ltd.

[0035] The ball-to-material ratio of ball milling is 30:1, the ball diameter is 3 mm, the ball milling time is 120 min, the drying temperature is 90 ° C, and the drying time is 24 h.

[0036] S2, placing the obtained first material in a tubular furnace for staged calcination to obtain a second material.

[0037] The process of staged calcination is as follows:

[0038] The first stage: heating to 620°C at a heating rate of 10°C / min in a nitrogen atmosphere and keeping the temperature for 130 min;

[0039] The second stage: in a nitrogen atmosphere, the temperature was raised to 1200°C at a heating rate of 4°C / min and kept at this temperature for 130 min;

[0040] The third stage: in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 1°C / min and kept at this temperature for 60 minutes.

[0041] S3, placing the second material in a reaction furnace and introducing carbon source gas to react, and after the reaction is completed, obtaining the third material.

[0042] Among them, propane is selected as the carbon source gas.

[0043] The flow rate of the carbon source gas was 10 sccm.

[0044] The pressure of the reactor is 200pa.

[0045] The reaction temperature is 2150°C.

[0046] S4. Wash the obtained third material twice with hydrofluoric acid and deionized water respectively, and then dry it to obtain high-purity silicon carbide powder.

[0047] Example 2

[0048] This embodiment provides a method for preparing high-purity silicon carbide powder, comprising the following steps:

[0049] S1. Add silicon material to the carbon-containing solution, and obtain the first material after ball milling and drying.

[0050] The carbon-containing solution is prepared by mixing carbon material and deionized water at a solid-liquid ratio of 0.04 g / mL.

[0051] Furthermore, the carbon material is wheat starch.

[0052] In this embodiment, it should be noted that wheat starch was purchased from Henan Temit Biotechnology Co., Ltd.

[0053] In addition, the silicon material is high-purity silicon powder, and the added amount of the silicon material is 2.6% of the mass of the carbon-containing solution.

[0054] In this embodiment, it should be noted that it was purchased from Kairui New Materials (Beijing) Technology Co., Ltd.

[0055] The ball-to-material ratio of ball milling is 31:1, the ball diameter is 4 mm, the ball milling time is 122 min, the drying temperature is 92 °C, and the drying time is 25 h.

[0056] S2, placing the obtained first material in a tubular furnace for staged calcination to obtain a second material.

[0057] The process of staged calcination is as follows:

[0058] The first stage: heating to 622°C at a heating rate of 11°C / min in a nitrogen atmosphere and keeping the temperature for 132 minutes;

[0059] The second stage: in a nitrogen atmosphere, the temperature was raised to 1210°C at a heating rate of 5°C / min and kept at this temperature for 132 minutes;

[0060] The third stage: in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 2°C / min and kept at this temperature for 62 minutes.

[0061] S3, placing the second material in a reaction furnace and introducing carbon source gas to react, and after the reaction is completed, obtaining the third material.

[0062] Among them, ethane is selected as the carbon source gas.

[0063] The flow rate of the carbon source gas was 20 sccm.

[0064] The pressure of the reactor is 210pa.

[0065] The reaction temperature is 2160°C.

[0066] S4. Wash the obtained third material with hydrofluoric acid and deionized water for three times respectively, and then dry it to obtain high-purity silicon carbide powder.

[0067] Example 3

[0068] This embodiment provides a method for preparing high-purity silicon carbide powder, comprising the following steps:

[0069] S1. Add silicon material to the carbon-containing solution, and obtain the first material after ball milling and drying.

[0070] The carbon-containing solution is prepared by mixing carbon material and deionized water at a solid-liquid ratio of 0.11 g / mL.

[0071] Furthermore, the carbon material is corn starch.

[0072] In this embodiment, it should be noted that corn starch was purchased from Chuzhou Xinfa Food Co., Ltd.

[0073] In addition, the silicon material is high-purity silicon powder, and the added amount of the silicon material is 3.4% of the mass of the carbon-containing solution.

[0074] In this embodiment, it should be noted that it was purchased from Kairui New Materials (Beijing) Technology Co., Ltd.

[0075] The ball-to-material ratio of ball milling is 33:1, the ball diameter is 4 mm, the ball milling time is 130 min, the drying temperature is 95 °C, and the drying time is 25 h.

[0076] S2, placing the obtained first material in a tubular furnace for staged calcination to obtain a second material.

[0077] The process of staged calcination is as follows:

[0078] The first stage: heating to 625°C at a heating rate of 11°C / min under nitrogen atmosphere and keeping the temperature for 135min;

[0079] The second stage: in a nitrogen atmosphere, the temperature was raised to 1250°C at a heating rate of 5°C / min and kept at this temperature for 135min;

[0080] The third stage: in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 2°C / min and kept at this temperature for 70 minutes.

[0081] S3, placing the second material in a reaction furnace and introducing carbon source gas to react, and after the reaction is completed, obtaining the third material.

[0082] Among them, butane is selected as the carbon source gas.

[0083] The flow rate of the carbon source gas was 55 sccm.

[0084] The pressure of the reactor is 260pa.

[0085] The reaction temperature is 2175°C.

[0086] S4. Wash the obtained third material with hydrofluoric acid and deionized water for three times respectively, and then dry it to obtain high-purity silicon carbide powder.

[0087] Example 4

[0088] This embodiment provides a method for preparing high-purity silicon carbide powder, comprising the following steps:

[0089] S1. Add silicon material to the carbon-containing solution, and obtain the first material after ball milling and drying.

[0090] The carbon-containing solution is prepared by mixing carbon material and deionized water at a solid-liquid ratio of 0.18 g / mL.

[0091] Furthermore, the carbon material is corn starch.

[0092] In this embodiment, it should be noted that corn starch was purchased from Chuzhou Xinfa Food Co., Ltd.

[0093] In addition, the silicon material is high-purity silicon powder, and the added amount of the silicon material is 3.4% of the mass of the carbon-containing solution.

[0094] In this embodiment, it should be noted that it was purchased from Kairui New Materials (Beijing) Technology Co., Ltd.

[0095] The ball-to-material ratio of ball milling is 34:1, the ball diameter is 4 mm, the ball milling time is 138 min, the drying temperature is 98 °C, and the drying time is 25 h.

[0096] S2, placing the obtained first material in a tubular furnace for staged calcination to obtain a second material.

[0097] The process of staged calcination is as follows:

[0098] The first stage: heating to 628°C at a heating rate of 11°C / min in a nitrogen atmosphere and keeping the temperature for 138 min;

[0099] The second stage: in a nitrogen atmosphere, the temperature was raised to 1290°C at a heating rate of 6°C / min and kept at this temperature for 138 min;

[0100] The third stage: in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 2°C / min and kept at this temperature for 78 minutes.

[0101] S3, placing the second material in a reaction furnace and introducing carbon source gas to react, and after the reaction is completed, obtaining the third material.

[0102] Among them, propane is selected as the carbon source gas.

[0103] The flow rate of the carbon source gas was 90 sccm.

[0104] The pressure of the reactor is 310pa.

[0105] The reaction temperature is 2190°C.

[0106] S4. Wash the obtained third material with hydrofluoric acid and deionized water for three times respectively, and then dry it to obtain high-purity silicon carbide powder.

[0107] Example 5

[0108] This embodiment provides a method for preparing high-purity silicon carbide powder, comprising the following steps:

[0109] S1. Add silicon material to the carbon-containing solution, and obtain the first material after ball milling and drying.

[0110] The carbon-containing solution is prepared by mixing carbon material and deionized water at a solid-liquid ratio of 0.2 g / mL.

[0111] Furthermore, the carbon material is selected from any one of corn starch and wheat starch.

[0112] In this embodiment, it should be noted that corn starch was purchased from Chuzhou Xinfa Food Co., Ltd., and wheat starch was purchased from Henan Temit Biotechnology Co., Ltd.

[0113] In addition, the silicon material is high-purity silicon powder, and the added amount of the silicon material is 4.4% of the mass of the carbon-containing solution.

[0114] In this embodiment, it should be noted that it was purchased from Kairui New Materials (Beijing) Technology Co., Ltd.

[0115] The ball-to-material ratio of ball milling is 35:1, the ball diameter is 5 mm, the ball milling time is 140 min, the drying temperature is 100 °C, and the drying time is 26 h.

[0116] S2, placing the obtained first material in a tubular furnace for staged calcination to obtain a second material.

[0117] The process of staged calcination is as follows:

[0118] The first stage: heating to 630°C at a heating rate of 12°C / min in a nitrogen atmosphere and keeping the temperature for 140 min;

[0119] The second stage: in a nitrogen atmosphere, the temperature was raised to 1300°C at a heating rate of 7°C / min and kept at this temperature for 140 min;

[0120] The third stage: in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 3°C / min and kept at this temperature for 80 minutes.

[0121] S3, placing the second material in a reaction furnace and introducing carbon source gas to react, and after the reaction is completed, obtaining the third material.

[0122] Among them, propane is selected as the carbon source gas.

[0123] The flow rate of the carbon source gas was 100 sccm.

[0124] The pressure of the reactor is 320pa.

[0125] The reaction temperature is 2200°C.

[0126] S4. Wash the obtained third material with hydrofluoric acid and deionized water for 4 times respectively, and then dry it to obtain high-purity silicon carbide powder.

[0127] Comparative Example 1: The difference from Example 1 is that the process of staged calcination in this example is as follows: in a nitrogen atmosphere, the temperature is increased to 630°C at a heating rate of 12°C / min, and the temperature is kept at this temperature for 140 minutes; then in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 3°C / min, and the temperature is kept at this temperature for 220 minutes.

[0128] Comparative Example 2: The difference from Example 1 is that the process of staged calcination in this example is as follows: in a nitrogen atmosphere, the temperature is increased to 1290°C at a heating rate of 6°C / min, and the temperature is kept at this temperature for 138 minutes; then in a vacuum environment, the temperature is increased to 1500°C at a heating rate of 2°C / min, and the temperature is kept at this temperature for 78 minutes.

[0129] Comparative Example 3: The difference from Example 1 is that this example does not contain step S3, that is, the second material is not placed in the reaction furnace and the carbon source gas is not introduced into the reaction furnace for reaction.

[0130] Performance test: The high-purity silicon carbide powder samples provided in Examples 1 to 5 and Comparative Examples 1 to 3 are marked as Examples 1 to 5 and Comparative Examples 1 to 3, respectively; and the relevant properties of the high-purity silicon carbide powder provided in Examples 1 to 5 and Comparative Examples 1 to 4 are tested as follows:

[0131] 1. Purity test: The test method is to use GDMS (glow discharge mass spectrometry) to detect the impurity content of each group of high-purity silicon carbide powder samples.

[0132] 2. Particle appearance test: The test method is to use an energy spectrometer to test each group of high-purity silicon carbide powder samples.

[0133] The obtained test data are recorded in Table 1 and Table 2 below:

[0134] Table 1 Impurity content test results of each group of high purity silicon carbide powder samples

[0135] Group Impurity content (ppm) Example 1 Group 1.68 Example 2 Group 1.62 Example 3 Group 1.72 Example 4 group 1.66 Example 5 group 1.72 Comparison group 1 15.4 Comparison of 2 groups 14.2 Comparison of 3 groups 20.2

[0136] Table 2 Appearance test results of each group of high-purity silicon carbide powder samples

[0137] Group appearance Example 1 Group Even particle distribution Example 2 Group Even particle distribution Example 3 Group Even particle distribution Example 4 group Even particle distribution Example 5 group Even particle distribution Comparison group 1 Uneven particle distribution Comparison of 2 groups Uneven particle distribution Comparison of 3 groups Uneven particle distribution

[0138] By comparing and analyzing the relevant data in Table 1 and Table 2, it can be seen that the high-purity silicon carbide powder prepared by the present invention not only has low impurity content and high purity, but also has excellent particle distribution, which effectively guarantees its quality. This shows that the preparation method of the high-purity silicon carbide powder provided by the present invention has a broader market prospect and is more suitable for promotion.

[0139] The present invention adds silicon material to a carbon-containing solution, and after ball milling and drying, obtains a first material, wherein the carbon material is selected from any one of corn starch and wheat starch; then the obtained first material is placed in a tubular furnace for staged calcination to obtain a second material; then the second material is placed in a reactor and a carbon source gas is introduced for reaction, and after the reaction is completed, a third material is obtained; finally, the obtained third material is washed with hydrofluoric acid and deionized water respectively, and after drying, a high-purity silicon carbide powder is obtained. The high-purity silicon carbide powder prepared by the present invention not only has a low impurity content and high purity, but also has an excellent particle distribution, which effectively guarantees its quality.

[0140] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0141] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing high-purity silicon carbide powder, It is characterized in that The following steps are involved: S1, adding silicon material to the carbon-containing solution, and obtaining a first material after ball milling and drying; S2, placing the obtained first material in a tubular furnace and calcining in stages to obtain a second material; S3, placing the second material in a reactor and introducing a carbon source gas to react, and obtaining a third material after the reaction is completed; S4. Wash the obtained third material with hydrofluoric acid and deionized water for 2 to 4 times respectively, and then dry it to obtain high-purity silicon carbide powder.

2. A method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In the step S1, the carbon-containing solution is prepared by mixing carbon material and deionized water at a solid-liquid ratio of 0.02 to 0.2 g / mL.

3. A method for preparing high-purity silicon carbide powder according to claim 2, It is characterized in that The carbon material is selected from any one of corn starch and wheat starch.

4. A method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In the step S1, the silicon material is high-purity silicon powder, and the added amount of the silicon material is 2.4-4.4% of the mass of the carbon-containing solution.

5. A method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In the step S1, the ball-to-material ratio of the ball milling is 30-35:1, the ball diameter is 3-5 mm, the ball milling time is 120-140 min, the drying temperature is 90-100° C., and the drying time is 24-26 h.

6. A method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In step S2, the process of the staged calcination is as follows: The first stage: heating to 620-630°C at a heating rate of 10-12°C / min in a nitrogen atmosphere and keeping the temperature for 130-140 minutes; The second stage: in a nitrogen atmosphere, the temperature is raised to 1200-1300°C at a heating rate of 4-7°C / min, and the temperature is kept for 130-140 minutes; The third stage: in a vacuum environment, the temperature is raised to 1500°C at a heating rate of 1 to 3°C / min and kept at this temperature for 60 to 80 minutes.

7. A method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In the step S3, the carbon source gas is selected from any one of propane, ethane and butane.

8. A method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In the step S3, the flow rate of the carbon source gas is 10-100 sccm.

9. The method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In the step S3, the pressure of the reaction furnace is 200-320 Pa.

10. The method for preparing high-purity silicon carbide powder according to claim 1, It is characterized in that In the step S3, the reaction temperature is 2150-2200°C.