Method for removing graphite paper carbon powder from high-purity silicon carbide powder
By combining flotation rinsing and combustion methods, using an ultrasonic cleaning machine and a vibration discharge device, the excess carbon and graphite paper in high-purity silicon carbide powder are efficiently removed, and the problems of unclean cleaning and poor removal effects in the prior art are solved, achieving efficient, stable and low-cost carbon removal effects, which are suitable for large-scale commercial applications.
Patent Information
- Application Number
- CN202411979626.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-05-02
AI Technical Summary
The existing high-purity silicon carbide powder removes graphite paper carbon powder, which has problems such as unclean cleaning, poor removal effect, consumes a lot of labor costs and water resources, increases the production costs of enterprises, and cannot be widely used on a large scale.
The flotation rinsing method and combustion method are combined with the method of combining the combustion method. The multiple cleaning tanks of the ultrasonic cleaning machine are washed successively, and the feed is evenly and slowly discharged by vibrating the feeding device, and the excess carbon powder is further removed during high-temperature drying and oxidation reactions.
It has achieved efficient removal of excess carbon and graphite paper, cleaned, had good carbon removal effect, high process stability, and low operation difficulty, reducing workers' labor intensity and production costs, and adapting to large-scale commercial application of high-purity silicon carbide powder.
Smart Images
Figure CN119911909A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of high-purity silicon carbide powder purification, and in particular to a method for removing graphite paper carbon powder from high-purity silicon carbide powder. Background Art
[0002] There are three main methods for synthesizing high-purity silicon carbide powder: solid phase method, liquid phase method, and gas phase method. Among them, the self-propagating high-temperature synthesis method in the solid phase method is currently the most commonly used method for synthesizing high-purity silicon carbide powder. This method uses silicon powder and carbon black as raw materials, reacts directly at 1800-2200℃, and ensures that the synthesis reaction is carried out continuously and effectively by increasing the synthesis temperature and continuously heating to generate high-purity silicon carbide powder.
[0003] The purity of silicon carbide powder used to grow silicon carbide single crystals is very high, and the impurity content should be at least less than 0.0001%. During the synthesis of high-purity silicon carbide powder, in order to ensure complete reaction, the carbon-silicon molar ratio is usually greater than 1 when the raw materials are mixed, resulting in a small amount of carbon remaining after synthesis. In order to ensure the purity requirements of silicon carbide powder, silicon carbide powder is usually purified after synthesis to remove excess carbon. At present, conventional carbon removal methods mainly include chemical carbon removal and physical carbon removal. Chemical carbon removal processes are generally divided into heating oxidation and chemical oxidation. Physical carbon removal methods are generally divided into flotation, heavy liquid separation, and hydrocyclone. In the silicon carbide semiconductor manufacturing process, the carbon removal method adopts a water washing method, and the silicon carbide powder is loaded into a container, and a shovel is used to turn the silicon carbide powder to float the carbon powder and graphite paper. Since silicon carbide accumulates in the water body, the carbon powder and graphite paper accumulated inside the silicon carbide cannot be floated by buoyancy. As a result, operators use shovels to turn the materials. In the process, not only a lot of water is wasted and the cleaning is not thorough, but also a lot of labor costs are consumed, increasing enterprise costs.
[0004] How to design a method that is reasonable and feasible, ingenious in design, clean, has good carbon removal effect, good process stability, low operating difficulty, reduces labor intensity of workers, reduces production costs, adapts to large-scale commercial applications of high-purity silicon carbide powder, and greatly reduces production costs to remove graphite paper carbon powder from high-purity silicon carbide powder is a problem that needs to be solved at present. Summary of the invention
[0005] In order to solve the technical problems existing in the existing process of removing graphite paper carbon powder from high-purity silicon carbide powder, such as unclean cleaning, poor effect of removing graphite paper carbon powder, large amount of labor cost, waste of water resources, increase of enterprise production cost, and inability to popularize and apply on a large scale, the present invention provides a method for removing graphite paper carbon powder from high-purity silicon carbide powder, so as to achieve the purpose of reasonable and feasible method, ingenious design, clean cleaning, good carbon removal effect, good process stability, low operation difficulty, reduced labor intensity of workers, lowered production cost, adapted to large-scale commercial application of high-purity silicon carbide powder, and greatly reduced production cost.
[0006] The technical solution adopted by the present invention to solve the above technical problems is: a method for removing carbon powder from graphite paper from high-purity silicon carbide powder, comprising the following steps: Step 1: The synthesized high-purity silicon carbide material is fed into a silo through a feed port, and a vibrating feeding device is provided below the silo; Step 2: Then start the crane, operate the lifting rod to lift the hanging basket with micropores on the surface, and place the hanging basket in the water tank of the ultrasonic cleaning machine just below the discharge port of the vibration feeding device. The high-purity silicon carbide material is slowly and evenly poured into the hanging basket through the vibration feeding device while being ultrasonically floated and rinsed; Step 3: The ultrasonic cleaning machine includes three cleaning tanks. There is a height difference between the first cleaning tank, the second cleaning tank, and the third cleaning tank. The hanging basket is sequentially suspended from the first cleaning tank at a low position to the third cleaning tank at a high position for flotation rinsing. When clean cleaning water continuously enters from a high position, impurities floating on the water surface flow to the next cleaning tank at a low position. Step 4: A filter screen is provided at the rear end of the first cleaning water tank, and the water with carbon powder impurities flowing out of the first cleaning water tank is filtered through the filter screen and then flows to the third cleaning water tank for recirculation and reuse; Step 5, collecting the silicon carbide material cleaned in step 3 and drying it at high temperature; Step six, further introduce high-purity oxygen or air to oxidize the remaining excess carbon powder to generate carbon dioxide for removal.
[0007] The above is a basic implementation of the present invention, and further improvements, perfections and limitations can be made on the above basis: for example, in step 1, the contact surfaces of the silo, the vibrating feeding device and the high-purity silicon carbide material are all made of plastic organic materials.
[0008] The above is a basic implementation of the present invention, and further improvements, perfections and limitations can be made on the above basis: for example, the micropore diameter of the hanging basket in step 2 is smaller than the high-purity silicon carbide material to prevent the material from spilling into the cleaning water tank.
[0009] The above is a basic implementation of the present invention, and further improvements, perfections and limitations can be made on the above basis: for example, in step 5, the drying temperature is 850-950° C., and the drying time is controlled to be 2-2.5 h.
[0010] The above is a basic implementation of the present invention, and further improvements, perfections and limitations can be made on the above basis: For example, the purity of the high-purity oxygen in step six is above 99.99%.
[0011] Compared with the prior art, the present invention has the following beneficial effects: First, the present invention adopts a combination of flotation rinsing method and combustion method. The flotation rinsing method uses an ultrasonic cleaning machine with multiple cleaning tanks to clean in sequence, and performs flotation carbon removal treatment to effectively remove excess carbon and graphite paper.
[0012] Secondly, the present invention uses a vibration device to evenly and slowly discharge the material, thereby ensuring that the silicon carbide powder will not have technical problems such as uneven materials and poor carbon removal effect caused by short-term large-scale accumulation.
[0013] Third, the present invention adopts a combination of multi-stage ultrasonic equipment and multiple cleaning water tanks. The silicon carbide material is always installed in the hanging basket and is cleaned step by step upward in the direction of the water flow, which greatly improves the cleaning efficiency.
[0014] Fourth, after cleaning, drying + aerobic purification technology is used, with a single purification volume of more than 30kg, which plays a positive role in the large-scale production and commercial use of high-purity silicon carbide powder.
[0015] Fifth, compared with traditional processes, the present invention is safe and risk-free to operate, greatly reducing the labor intensity of employees. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a schematic diagram of the process of removing carbon powder from graphite paper according to the present invention; In the figure, 1. silo, 2. vibration unloading device, 3. ultrasonic cleaning machine, 4. first cleaning sink, 5. second cleaning sink, 6. third cleaning sink, 7. lifting rod, 8. hanging basket. DETAILED DESCRIPTION
[0017] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.
[0018] Example 1 As shown in the figure, Figure 1 This is a schematic diagram of the process of removing carbon powder from graphite paper according to the present invention; A method for removing carbon powder from graphite paper from high-purity silicon carbide powder comprises the following steps: Step 1: The synthesized high-purity silicon carbide material is fed into a silo through a feed port, and a vibrating feeding device is provided below the silo; Step 2: Then start the crane, operate the lifting rod to lift the hanging basket with micropores on the surface, and place the hanging basket in the water tank of the ultrasonic cleaning machine just below the discharge port of the vibration feeding device. The high-purity silicon carbide material is slowly and evenly poured into the hanging basket through the vibration feeding device while being ultrasonically floated and rinsed; Step 3: The ultrasonic cleaning machine includes three cleaning tanks. There is a height difference between the first cleaning tank, the second cleaning tank, and the third cleaning tank. The hanging basket is sequentially suspended from the first cleaning tank at a low position to the third cleaning tank at a high position for flotation rinsing. When clean cleaning water continuously enters from a high position, impurities floating on the water surface flow to the next cleaning tank at a low position. Step 4: A filter screen is provided at the rear end of the first cleaning water tank, and the water with carbon powder impurities flowing out of the first cleaning water tank is filtered through the filter screen and then flows to the third cleaning water tank for recirculation and reuse; Step 5, collecting the cleaned silicon carbide material in step 3 and drying it at high temperature, wherein the drying temperature in step 5 is 850° C. and the drying time is controlled to be 2.5 h; In step six, high-purity oxygen or air is further introduced to oxidize the remaining excess carbon powder to generate carbon dioxide for removal. The purity of the high-purity oxygen in step six is above 99.99%.
[0019] Example 2 A method for removing carbon powder from graphite paper from high-purity silicon carbide powder comprises the following steps: Step 1: The synthesized high-purity silicon carbide material is fed into a silo through a feed port, and a vibrating feeding device is provided below the silo; Step 2: Then start the crane, operate the lifting rod to lift the hanging basket with micropores on the surface, and place the hanging basket in the water tank of the ultrasonic cleaning machine just below the discharge port of the vibration feeding device. The high-purity silicon carbide material is slowly and evenly poured into the hanging basket through the vibration feeding device while being ultrasonically floated and rinsed; Step 3: The ultrasonic cleaning machine includes three cleaning tanks. There is a height difference between the first cleaning tank, the second cleaning tank, and the third cleaning tank. The hanging basket is sequentially suspended from the first cleaning tank at a low position to the third cleaning tank at a high position for flotation rinsing. When clean cleaning water continuously enters from a high position, impurities floating on the water surface flow to the next cleaning tank at a low position. Step 4: A filter screen is provided at the rear end of the first cleaning water tank, and the water with carbon powder impurities flowing out of the first cleaning water tank is filtered through the filter screen and then flows to the third cleaning water tank for recirculation and reuse; Step 5, collecting the cleaned silicon carbide material in step 3 and drying it at high temperature, wherein the drying temperature in step 5 is 900° C. and the drying time is controlled to be 2.2 h; In step six, high-purity oxygen or air is further introduced to oxidize the remaining excess carbon powder to generate carbon dioxide for removal. The purity of the high-purity oxygen in step six is above 99.99%.
[0020] Example 3 A method for removing carbon powder from graphite paper from high-purity silicon carbide powder comprises the following steps: Step 1: The synthesized high-purity silicon carbide material is fed into a silo through a feed port, and a vibrating feeding device is provided below the silo; Step 2: Then start the crane, operate the lifting rod to lift the hanging basket with micropores on the surface, and place the hanging basket in the water tank of the ultrasonic cleaning machine just below the discharge port of the vibration feeding device. The high-purity silicon carbide material is slowly and evenly poured into the hanging basket through the vibration feeding device while being ultrasonically floated and rinsed; Step 3: The ultrasonic cleaning machine includes three cleaning tanks. There is a height difference between the first cleaning tank, the second cleaning tank, and the third cleaning tank. The hanging basket is sequentially suspended from the first cleaning tank at a low position to the third cleaning tank at a high position for flotation rinsing. When clean cleaning water continuously enters from a high position, impurities floating on the water surface flow to the next cleaning tank at a low position. Step 4: A filter screen is provided at the rear end of the first cleaning water tank, and the water with carbon powder impurities flowing out of the first cleaning water tank is filtered through the filter screen and then flows to the third cleaning water tank for recirculation and reuse; Step 5, collecting the cleaned silicon carbide material in step 3 and drying it at high temperature, wherein the drying temperature in step 5 is 950° C. and the drying time is controlled to be 2 hours; In step six, high-purity oxygen or air is further introduced to oxidize the remaining excess carbon powder to generate carbon dioxide for removal. The purity of the high-purity oxygen in step six is above 99.99%.
[0021] In practical applications, the contact surfaces of the silo, the vibrating feeding device and the high-purity silicon carbide material in step 1 are all made of plastic organic materials, which effectively prevents additional impurities from being mixed into metal materials or other devices containing graphite materials.
[0022] In the step 2, the diameter of the micropores of the hanging basket is smaller than that of the high-purity silicon carbide material to prevent the material from spilling into the cleaning water tank.
[0023] When cleaning in the first cleaning tank, the high-purity silicon carbide material is slowly and evenly poured into the hanging basket through the vibrating feeding device, while being ultrasonically floated and rinsed. Some carbon powder particles contained in the material fall into the cleaning tank during the falling process, and the effect of cleaning while feeding is better.
[0024] The present invention adopts three cleaning water tanks. In specific applications, the number of water tanks suitable for enterprise production can be selected according to the purity of high-purity silicon carbide materials, but the present invention is not limited to this.
[0025] The method of the invention is reasonable and feasible, has an ingenious design, cleans cleanly, has a good carbon removal effect, has good process stability, is easy to operate, reduces the labor intensity of workers, reduces production costs, is suitable for large-scale commercial applications of high-purity silicon carbide powder, greatly reduces production costs, and solves the technical problems of unclean cleaning, poor graphite paper carbon powder removal effect, large labor costs, waste of water resources, increased production costs of enterprises, and inability to be widely popularized and applied in the existing high-purity silicon carbide powder removal process. Compared with the existing technology, the method has a good market prospect and development space.
[0026] The preferred specific implementation modes and embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes and embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the concept of the present invention.
Claims
1. A method for removing carbon powder from graphite paper from high-purity silicon carbide powder, characterized in that: The following steps are included: Step 1: The synthesized high-purity silicon carbide material is fed into a silo through a feed port, and a vibrating feeding device is provided below the silo; Step 2: Then start the crane, operate the lifting rod to lift the hanging basket with micropores on the surface, and place the hanging basket in the water tank of the ultrasonic cleaning machine just below the discharge port of the vibration feeding device. The high-purity silicon carbide material is slowly and evenly poured into the hanging basket through the vibration feeding device while being ultrasonically floated and rinsed; Step 3: The ultrasonic cleaning machine includes three cleaning tanks. There is a height difference between the first cleaning tank, the second cleaning tank, and the third cleaning tank. The hanging basket is sequentially suspended from the first cleaning tank at a low position to the third cleaning tank at a high position for flotation rinsing. When clean cleaning water continuously enters from a high position, impurities floating on the water surface flow to the next cleaning tank at a low position. Step 4: A filter screen is provided at the rear end of the first cleaning water tank, and the water with carbon powder impurities flowing out of the first cleaning water tank is filtered through the filter screen and then flows to the third cleaning water tank for recirculation and reuse; Step 5, collecting the silicon carbide material cleaned in step 3 and drying it at high temperature; Step six, further introduce high-purity oxygen or air to oxidize the remaining excess carbon powder to generate carbon dioxide for removal.
2. A method for removing carbon powder from graphite paper using high-purity silicon carbide powder as claimed in claim 1, characterized in that: In the step 1, the contact surfaces of the material bin, the vibrating feeding device and the high-purity silicon carbide material are all made of plastic organic material.
3. A method for removing carbon powder from graphite paper using high-purity silicon carbide powder as claimed in claim 1, characterized in that: In the step 2, the diameter of the micropores of the hanging basket is smaller than that of the high-purity silicon carbide material to prevent the material from spilling into the cleaning water tank.
4. A method for removing carbon powder from graphite paper using high-purity silicon carbide powder as claimed in claim 1, characterized in that: In step 5, the drying temperature is 850-950° C., and the drying time is controlled to be 2-2.5 hours.
5. The method for removing carbon powder from graphite paper from high-purity silicon carbide powder as claimed in claim 1, characterized in that: The purity of the high-purity oxygen in step six is above 99.99%.