Rapid verification method for synthetic quartz sand

Abstract

The invention relates to a rapid verification method for synthetic quartz sand, and belongs to the technical field of quartz sand verification. According to the rapid verification method for the synthetic quartz sand, only a small amount of quartz sand is needed to be melted into the quartz glass balls, the quality of the synthetic quartz sand can be rapidly inspected at low cost by detecting the appearance, hydroxyl and the like of the quartz glass balls, and the rapid verification method is particularly suitable for rapid verification of the synthetic quartz sand.

Description

Technical Field

[0001] The present invention relates to a rapid verification method for synthetic quartz sand, belonging to the technical field of quartz sand verification. Background Art

[0002] Due to higher purity and fewer inclusions than natural quartz sand, the synthetic quartz materials melted from synthetic quartz sand have become important components in the high-end optical field and the semiconductor chip etching process below 10nm process.

[0003] During the R & D process of synthetic quartz sand, it is necessary to continuously verify the quality of synthetic quartz sand to determine whether the production process needs to be improved and whether the product quality is stable. The most important indicators of synthetic quartz sand are impurity content, gas-liquid inclusion content, hydroxyl content, particle size distribution, etc. However, ultimately, it is necessary to evaluate the quality of quartz glass after melting it into quartz glass.

[0004] Currently, the verification method for synthetic quartz sand is to verify it after melting it into a quartz ingot through a quartz sand electric furnace or a gas furnace. During the process of melting a quartz ingot through a quartz sand electric furnace or a gas furnace, each melting requires at least 30 kg and takes three days for melting. The energy consumed by the melting furnace during the melting process is also very large, having problems of long time consumption and large energy consumption.

[0005] Therefore, it is necessary to develop a new rapid verification method for synthetic quartz sand to solve the above problems existing in the existing verification method. Summary of the Invention

[0006] The purpose of the present invention is to provide a rapid verification method for synthetic quartz sand to solve the problems of long time consumption and large energy consumption existing in the existing verification method for synthetic quartz sand.

[0007] The technical solution of the present invention is as follows: A rapid verification method for synthetic quartz sand, characterized in that the rapid verification method for synthetic quartz sand includes the following steps: First step: Pretreatment of quartz sand; First, wash and dry the quartz sand. By washing the quartz sand, the ultrafine powder on the surface of the sand material is removed to avoid generating bubbles during the melting process; then screen the quartz sand to 80 - 180 mesh. The quartz sand of this particle size has uniform feeding and good melting effect during gas smelting; Second step: Preparation work; Use a belt-type mobile trolley to push one end of the mother rod near the furnace inlet, and at the same time fill the feeding device with quartz sand; Third step: Preheat the furnace chamber of the melting furnace; First, introduce hydrogen and oxygen into the hydrogen and oxygen burner to preheat the furnace of the melting furnace 1, observe the furnace temperature and measure it with a temperature gun, and when the temperature reaches 1800°C, preheat for 5-15 minutes, and the ratio of hydrogen and oxygen is 2:1; during the preheating period, the mother rod can be slowly pushed to the bottom of the feeding port in the furnace; Step 4: Feeding; After preheating, open the feeding device to feed material to one end of the mother rod at a feeding speed of 15g / min, and increase or decrease the feeding speed according to the quartz sand material situation; Step 5: Make the ball; Use a belt-type mobile cart to rotate the mother rod at a speed of 50r / min, observe the material melting situation, and slowly push the mother rod forward to make the quartz sand melt evenly on the mother rod. After pushing it forward for 5-10cm, start pushing the mother rod backward in the opposite direction. By moving the rotating mother rod back and forth, the quartz sand can be melted on the mother rod layer by layer; Step 6: Cut the ball; After the material is unloaded, quartz glass balls will be melted on the mother rod, and the belt-type mobile cart 5 will be slowly pulled out. After the quartz glass balls are cooled, the mother rod will be taken out, and the quartz glass balls will be cut off with a cutting device; Step 7: Testing: Visual inspection: The quality of the sand can be quickly and easily determined by the appearance of the quartz glass ball. First, observe whether the quartz glass ball is transparent. If the quartz glass ball is milky white and opaque, it may be due to insufficient sintering temperature during the preparation of synthetic sand, resulting in insufficient density inside the sand. Secondly, observe the bubbles inside the quartz glass ball. If they are dense and small bubbles, it may be due to a short densification time during the preparation of synthetic sand, resulting in a high hydroxyl content inside the sand. Finally, observe whether there are foreign matter, discoloration, or stones in the quartz glass ball. If metal impurities in the equipment are introduced into individual sand materials during the preparation of synthetic quartz sand, obvious color spots or stones will appear after melting. If there are many gas-liquid inclusions inside the sand, bubbles or color spots will also appear in the quartz glass ball. If the overall impurities in the quartz sand are too high, the quartz glass ball will change color after melting.

[0008] Hydroxyl detection: The quartz glass ball is processed into a quartz glass sheet with a length, width and thickness of 20×20mm and a thickness of 2mm by a diamond abrasive wire cutting machine, and the upper and lower surfaces of the quartz sheet are polished, and the parallel thickness difference is ≤0.1mm, thereby obtaining a hydroxyl test sheet, and its hydroxyl content is obtained by detecting the infrared transmittance of the quartz sheet; since the quartz glass ball is melted using an oxyhydrogen flame burner, this will increase the hydroxyl content of the sand during the melting process. When making a hydroxyl judgment, the detected hydroxyl value minus 100ppm can usually be used to obtain the hydroxyl content of the synthetic quartz sand.

[0009] The melting equipment described above includes a melting furnace, a belt-type mobile cart, a feeding device, and an exhaust system; characterized in that: an exhaust system is connected to the upper end of the melting furnace; a hydrogen-oxygen burner is installed at the bottom end of the hearth of the melting furnace; a feeding device is installed above the hydrogen-oxygen burner; a belt-type mobile cart is arranged on one side of the melting furnace; the belt-type mobile cart is equipped with a driving device, and a mother bar is installed on the driving device; one end of the mother bar passes through the melting furnace and extends into the hearth interior; one end of the mother bar is located between the hydrogen-oxygen burner and the feeding device.

[0010] A visual window is arranged on the outer side of the melting furnace.

[0011] A circulating water system is arranged inside the melting furnace to cool the furnace body shell.

[0012] The feeding device described above consists of a funnel and a vibrator, and the feeding speed of quartz sand is adjusted by controlling the vibration frequency of the vibrator.

[0013] The exhaust device described above timely discharges the high-temperature gas and moisture in the furnace body to maintain the pressure and temperature balance in the furnace.

[0014] The advantages of the present invention are as follows: For the rapid verification method of the synthetic quartz sand, only a small amount of quartz sand is needed to be melted into quartz glass balls, and by detecting the appearance, hydroxyl groups, etc. of the quartz glass balls, the quality of the synthetic quartz sand can be quickly and low-costly inspected. Traditional inspection of quartz sand usually requires more than 30 kg of sand material, and it takes 3 - 4 days to melt the quartz glass ingot. On the one hand, this causes a great waste of synthetic quartz sand, and on the other hand, it also consumes a large amount of energy, making the R & D cost of synthetic quartz sand remain high. While the present invention can be melted with only a small amount of quartz sand under the condition of saving a large amount of energy, reducing the waste of quartz sand, shortening the verification cycle of quartz sand, and greatly reducing the R & D cost of synthetic quartz sand. And the detection data obtained by this method is fast and accurate, and it also makes up for the problem that quartz sand cannot accurately detect hydroxyl groups. Description of the Drawings

[0015] Figure 1 It is a structural schematic diagram of the melting equipment in this application; Figure 2 It is a structural diagram of quartz glass ball A during the test of this application; Figure 3 It is a structural diagram of quartz glass ball B during the test of this application; Figure 4 It is a structural diagram of quartz glass ball C during the test of this application.

[0016] In the figure: 1. Melting furnace; 2. Exhaust system; 3. Hydrogen-oxygen burner; 4. Feeding device; 5. Belt-type mobile cart; 6. Mother bar. Detailed implementation mode

[0017] The melting equipment used in the rapid verification method of the synthetic quartz sand includes a melting furnace 1, a belt-type mobile cart 5, a feeding device 4, and an exhaust system 2 (see the attached Figure 1 )

[0018] The upper end of the melting furnace 1 is connected to the exhaust system 2; the exhaust system 2 can timely discharge the high-temperature gas and moisture in the furnace body to maintain the pressure and temperature balance in the furnace. A visual window is provided on the outside of the melting furnace 1. During operation, the situation inside the furnace can be observed through the visual window. A circulating water system is provided inside the melting furnace 1 to cool the furnace body shell

[0019] A hydrogen-oxygen burner 3 is installed at the bottom end of the furnace chamber of the melting furnace 1; a feeding device 4 is installed above the hydrogen-oxygen burner 3

[0020] Both the hydrogen-oxygen burner 3 and the feeding device 4 are off-the-shelf equipment. The feeding device 4 consists of a funnel and a vibrator, and the feeding speed of the quartz sand is adjusted by controlling the vibration frequency of the vibrator. The feeding device 4 is produced by Hai'an Zhikang Vibrating Machinery Co., Ltd., and the model is GZV

[0021] The hydrogen-oxygen burner 3 is produced by Hubei Fiberglass Co., Ltd., and the model is type 27. A belt-type mobile cart 5 is provided on one side of the melting furnace 1 (see the attached Figure 1 ) The belt-type mobile cart 5 is produced by Jingzhou Parabolic Electromechanical Co., Ltd. A mother bar 6 is installed on the belt-type mobile cart 5 through a driving device; one end of the mother bar 6 passes through the melting furnace 1 and extends into the furnace chamber; one end of the mother bar 6 is located between the hydrogen-oxygen burner 3 and the feeding device 4

[0022] The rapid verification method of the synthetic quartz sand includes the following steps First step: Pretreatment of quartz sand

[0023] First, wash and dry the quartz sand. By washing the quartz sand, the ultra-fine powder on the surface of the sand material is removed to avoid the generation of bubbles during the melting process; then screen the quartz sand to 80-180 mesh. The quartz sand of this particle size has uniform feeding and good melting effect during gas refining Second step: Preparation work Use the belt-type mobile cart 5 to push one end of the mother bar 6 near the furnace chamber entrance, and at the same time fill the feeding device 4 with quartz sand Third step: Preheat the melting furnace 1 First, introduce hydrogen and oxygen into the hydrogen-oxygen burner 3 to preheat the furnace chamber of the melting furnace 1. Observe the furnace temperature and measure it with a temperature measuring gun. After the temperature reaches 1800°C, preheat for 5-15 minutes, and the hydrogen-oxygen ratio is 2:1; during the preheating period, the mother bar 6 can be slowly pushed under the feeding port of the feeding device 4 in the furnace chamber Fourth step: Feeding After preheating, open the feeding device 4 to feed the material to one end of the mother rod 6, the feeding speed is 15g / min, and the feeding speed is increased or decreased according to the quartz sand material situation; Step 5: Make the ball; The mother rod 6 is rotated by the belt-type moving trolley 5 at a speed of 50r / min. The material melting condition is observed and the mother rod 6 is slowly pushed forward to make the quartz sand melt evenly on the mother rod 6. After pushing forward 5-10cm, the mother rod 6 is pushed backward in the opposite direction. The quartz sand can be melted layer by layer on the mother rod 6 by moving the rotating mother rod 6 back and forth. Step 6: Cut the ball; After the material is unloaded, quartz glass balls will be melted on the mother rod 6, and the belt-type mobile cart 5 will be slowly pulled out. After the quartz glass balls are cooled, the mother rod 6 will be taken out, and the quartz glass balls will be cut off with a cutting device; Step 7: Test the quartz glass ball.

[0024] Visual inspection: The quality of the sand can be quickly and easily determined by the appearance of the quartz glass ball. First, observe whether the quartz glass ball is transparent. If the quartz glass ball is milky white and opaque, it may be due to insufficient sintering temperature during the preparation of synthetic sand, resulting in insufficient density inside the sand. Secondly, observe the bubbles inside the quartz glass ball. If they are dense and small bubbles, it may be due to a short densification time during the preparation of synthetic sand, resulting in a high hydroxyl content inside the sand. Finally, observe whether there are foreign matter, discoloration, or stones in the quartz glass ball. If metal impurities in the equipment are introduced into individual sand materials during the preparation of synthetic quartz sand, obvious color spots or stones will appear after melting. If there are many gas-liquid inclusions inside the sand, bubbles or color spots will also appear in the quartz glass ball. If the overall impurities in the quartz sand are too high, the quartz glass ball will change color after melting.

[0025] Hydroxyl detection: The quartz glass ball is processed into a quartz glass sheet with a length, width and thickness of 20×20mm and a thickness of 2mm by a diamond abrasive wire cutting machine, and the upper and lower surfaces of the quartz sheet are polished, and the parallel thickness difference is ≤0.1mm, thereby obtaining a hydroxyl test sheet, and its hydroxyl content is obtained by detecting the infrared transmittance of the quartz sheet; since the quartz glass ball is melted using an oxyhydrogen flame burner, this will increase the hydroxyl content of the sand during the melting process. When making a hydroxyl judgment, the detected hydroxyl value minus 100ppm can usually be used to obtain the hydroxyl content of the synthetic quartz sand.

[0026] In order to verify the feasibility of the present application, the present application carried out melting and testing on three kinds of synthetic quartz sand A, synthetic quartz sand B and synthetic quartz sand C. Example 1

[0027] After taking 300 g of synthetic quartz sand A, it is screened, washed with water, dried, and then poured into the feeding device 4. A mother rod 6 with a diameter of 38 mm and a length of 1 m is fixed on the belt mobile cart 5, and one end of the mother rod 6 is moved into the furnace. After setting the hydrogen-oxygen ratio to 2:1, the furnace is preheated to 1800 °C for 10 min. After the preheating is completed, the feeding speed of the feeding device 4 is set to 15 g / min. Manually adjust the hydrogen-oxygen flame of the hydrogen-oxygen burner 3 to align with one end of the mother rod 6, and make the sand material fall onto the mother rod 6. While the quartz sand melts on the mother rod 6, manually adjust the rotation speed and translation direction of the mother rod. After all the synthetic quartz sand A is fed and melted, take out the mother rod 6 and cool it. After cooling, cut off the melted quartz glass balls to obtain quartz glass balls A (see the attached Figure 2 )

[0028] The quartz glass balls A are completely transparent, with good bubble quality, only scattered and tiny bubbles, and no foreign objects, discoloration, stones, etc. Based on this, it can be preliminarily judged that the melting effect of the synthetic quartz sand A is good, no more metal impurities are introduced during the preparation process, and the dehydroxylation treatment is complete.

[0029] Use a diamond wire cutting machine to process the quartz glass balls A into quartz glass sheets with a length and width of 20×20 mm and a thickness of 2 mm. After polishing the light-transmitting surface, perform hydroxyl detection. The obtained results are shown in Table 1A. Since some hydroxyl groups will be introduced into the quartz glass during gas refining and melting, the hydroxyl groups in the quartz glass melted by this process are about 100 ppm higher than those in the sand before melting. It can be seen that the hydroxyl groups of the synthetic quartz sand A are at a relatively low level. Example 2

[0030] After taking 300 g of synthetic quartz sand B, it is screened, washed with water, dried, and then poured into the feeding device 4. A mother rod 6 with a diameter of 38 mm and a length of 1 m is fixed on the belt mobile cart 5, and one end of the mother rod 6 is moved into the furnace. After setting the hydrogen-oxygen ratio to 2:1, the furnace is preheated to 1800 °C for 10 min. After the preheating is completed, set the feeding speed of the feeding device 4 to 15 g / min. Manually adjust the hydrogen-oxygen flame of the hydrogen-oxygen burner 3 to align with one end of the mother rod 6, and make the sand material fall onto the mother rod 6. While the quartz sand melts on the mother rod 6, manually adjust the rotation speed and translation direction of the mother rod 6. After all the synthetic sand a is fed and melted, take out the mother rod 6 and cool it. After cooling, cut off the melted quartz glass balls to obtain quartz glass balls B (see the attached Figure 3 )

[0031] The quartz glass balls B have more dense bubbles, and there are no foreign objects, discoloration, stones, etc. It can be preliminarily judged that the dehydroxylation effect of the synthetic sand is poor. Although transparent quartz glass can be normally melted, the hydroxyl groups in the sand material are relatively high.

[0032] The quartz glass ball B is processed by a silicon carbide wire cutting machine to obtain a quartz glass sheet with a length and width of 20×20 mm and a thickness of 2 mm. After the light-transmitting surface is polished, hydroxyl detection is carried out, and the obtained results are shown in Table 1. It can be seen that the hydroxyl of the synthetic sand a is at a relatively high level. Example 3

[0033] Take 300 g of synthetic quartz sand C, screen, wash and dry it, and then pour it into the feeding device 4. Take a mother rod 6 with a diameter of 38 mm and a length of 1 m, fix it on the belt-type mobile cart 5, and move one end of the mother rod 6 into the furnace. After setting the hydrogen-oxygen ratio to 2:1, preheat the furnace to 1800 °C for 10 min. After the preheating is completed, set the feeding speed of the feeding device 4 to 15 g / min, manually adjust the hydrogen-oxygen burner 3 to align with one end of the mother rod 6, and make the sand material fall onto the mother rod 6. While the quartz sand is melting on the mother rod 6, manually adjust the rotation speed and translation direction of the mother rod 6. After all the synthetic sand b is fed and melted, take out the mother rod 6 and cool it. After cooling, cut off the melted quartz glass ball to obtain the quartz glass ball C (see the attached Figure 4 ).

[0034] The quartz glass ball C is overall transparent, the bubble quality is good, and there are no foreign objects, discoloration, stones, etc. It can be preliminarily judged that the hydroxyl of this synthetic sand is relatively low and the melting effect is good.

[0035] The quartz glass ball C is processed by a silicon carbide wire cutting machine to obtain a quartz glass sheet with a length and width of 20×20 mm and a thickness of 2 mm. After the light-transmitting surface is polished, hydroxyl detection is carried out, and the obtained results are shown in Table 1. It can be seen that the hydroxyl of the synthetic sand b is at a relatively low level.

[0036] ; Table 1 The rapid verification method of this synthetic quartz sand only needs a small amount of quartz sand to be melted into a quartz glass ball, and by detecting the appearance, hydroxyl, etc. of this quartz glass ball, the quality of the synthetic quartz sand can be quickly and low-costly inspected, which is especially suitable for the rapid verification of synthetic quartz sand.

Claims

1. A rapid verification method for synthetic quartz sand, characterized in that: The rapid verification method of the synthetic quartz sand comprises the following steps: Step 1: Quartz sand pretreatment; Step 2: Preparation; Use a belt-type mobile cart (5) to push one end of the mother rod (6) to the vicinity of the furnace entrance, and at the same time fill the unloading device (4) with quartz sand; Step 3: Preheating the melting furnace (1); Step 4: Feeding; After preheating is completed, the feeding device (4) is turned on to feed material to one end of the mother rod (6) at a feeding speed of 15 g / min, and the feeding speed is increased or decreased according to the quartz sand material situation; Step 5: Make the ball; The mother rod (6) is rotated by a belt-type moving cart (5) at a speed of 50 r / min, the material dissolution is observed, and the mother rod (6) is slowly pushed forward to make the quartz sand melt evenly on the mother rod (6). After pushing the mother rod (6) forward for 5-10 cm, the mother rod (6) is pushed backward in the opposite direction. The quartz sand can be melted layer by layer on the mother rod (6) by moving the rotating mother rod (6) back and forth; Step 6: Cut the ball; After the material is unloaded, quartz glass balls are melted on the mother rod (6), the belt-type mobile cart (5) is slowly pulled out, and after the quartz glass balls are cooled, the mother rod (6) is taken out and the quartz glass balls are cut off with a cutting device; Step 7: Test the quartz glass ball.

2. A rapid verification method for synthetic quartz sand according to claim 1, characterized in that: The specific steps of the first step are as follows: First, wash and dry the quartz sand to remove the ultrafine powder on the surface of the sand material and avoid bubbles generated by the fine powder during the melting process; then sieve the quartz sand to 80-180 mesh. Quartz sand with this particle size can be fed evenly and has a good melting effect during gas refining.

3. The rapid verification method of synthetic quartz sand according to claim 1, characterized in that: The specific steps of the third step are as follows: First, hydrogen and oxygen are introduced into the hydrogen and oxygen burner (3) to preheat the furnace of the melting furnace (1). The furnace temperature is observed and measured with a temperature measuring gun. When the temperature reaches 1800° C., preheat for 5-15 minutes, and the ratio of hydrogen and oxygen is 2:

1. During the preheating period, the mother rod (6) can be slowly pushed to the bottom of the discharge port of the discharge device (4) in the furnace.

4. The rapid verification method of synthetic quartz sand according to claim 1, characterized in that: The seventh step: testing the quartz glass ball includes visual inspection and hydroxyl detection; the steps of visual inspection and hydroxyl detection are as follows: Visual inspection; the quality of the sand can be quickly and easily determined by the appearance of the quartz glass ball; first, observe whether the quartz glass ball is transparent. If the quartz glass ball is milky white and opaque, it may be due to insufficient sintering temperature during the preparation of the synthetic sand, resulting in insufficient density inside the sand. Secondly, observe the bubbles inside the quartz glass ball. If they are dense and small bubbles, it may be due to a short densification time during the preparation of the synthetic sand, resulting in a high hydroxyl content inside the sand; finally, observe whether there are foreign matter, discoloration, or stones in the quartz glass ball. If metal impurities in the equipment are introduced into individual sand materials during the preparation of synthetic quartz sand, obvious color spots or stones will appear after melting; if there are more gas-liquid inclusions inside the sand material, bubbles or color spots will also appear in the quartz glass ball; if the overall impurities in the quartz sand are too high, the quartz glass ball will change color after melting; Hydroxyl detection: The quartz glass ball is processed into a quartz glass sheet with a length, width and thickness of 20×20mm and a thickness of 2mm by a diamond abrasive wire cutting machine, and the upper and lower surfaces of the quartz sheet are polished, and the parallel thickness difference is ≤0.1mm, thereby obtaining a hydroxyl test sheet, and its hydroxyl content is obtained by detecting the infrared transmittance of the quartz sheet; since the quartz glass ball is melted using an oxyhydrogen flame burner, this will increase the hydroxyl content of the sand during the melting process. When making a hydroxyl judgment, the detected hydroxyl value minus 100ppm can usually be used to obtain the hydroxyl content of the synthetic quartz sand.

5. The rapid verification method of synthetic quartz sand according to claim 1, characterized in that: The melting device comprises a melting furnace (1), a belt-type moving trolley (5), a material unloading device (4), and an exhaust system (2); the upper end of the melting furnace (1) is connected to the exhaust system (2); a hydrogen-oxygen burner (3) is installed at the bottom of the furnace of the melting furnace (1); the upper end of the hydrogen-oxygen burner (3) is installed with a material unloading device (4); a belt-type moving trolley (5) is arranged on one side of the melting furnace (1); a mother rod (6) is installed on the belt-type moving trolley (5) through a driving device; one end of the mother rod (6) passes through the melting furnace (1) and extends to the inside of the furnace; one end of the mother rod (6) is located between the hydrogen-oxygen burner (3) and the material unloading device (4).

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