A system for qualitatively detecting trace amounts of silicon in unknowns

Abstract

The utility model discloses a system for qualitative detection trace silicon in unknown object, including generator, sodium hydroxide feed arrangement, gas detection device and emptying device, and the generator includes generator body and sets the thing tray in the generator body, is equipped with the opening on the generator body upper end, is equipped with the sealing plug in the opening, is equipped with the through -hole I, through -hole II and through -hole III for device installation on the sealing plug, the thing tray is the thing tray of mesh adjustable, and sodium hydroxide feed arrangement includes feeding hopper and feed pipe, and gas detection device includes detection tube and the piston of setting in detection tube, is equipped with the scale on detection tube, and emptying device includes emptying air pipe, pipette and liquid tank, is equipped with the check valve on emptying air pipe, and pipette end extends to below liquid level in liquid tank, is equipped with the scale on pipette. The system can realize qualitative detection trace silicon in unknown object fast, efficiently, and the error is less, to provide reference basis for silicon analysis in unknown sample.

Description

Technical Field

[0001] This utility model relates to the technical field of detection devices in polycrystalline silicon production, and specifically to a system for qualitatively detecting trace amounts of silicon in unknown substances, and more specifically to a system for qualitatively detecting trace amounts of elemental silicon in unknown substances. Background Technology

[0002] During polysilicon production, a series of unknown substances are often generated due to factors such as stainless steel pipes, metal equipment, or side reactions. Qualitative and quantitative analysis of silicon in these unknown samples helps to effectively assess the usage of raw materials or intermediate products and provides important evidence for the analysis of impurities generated during the production process.

[0003] Currently, the analysis of silicon in unknown samples generally involves detecting the silica content. This process typically involves dissolving the silica with hydrofluoric acid, digesting the remaining sample with a mixture of hydrofluoric acid and nitric acid, and finally determining the silicon content using inductively coupled plasma optical emission spectrometry (ICP-OES). However, this method has limitations. Hydrofluoric acid (HF) reacts with elemental silicon (Si), potentially causing the silicon to dissolve and introducing errors in the analysis of silica (SiO2). Specifically, the reaction of hydrofluoric acid (HF) with elemental silicon (Si) produces volatile silicon tetrafluoride (SiF4), leading to an overestimation of the silicon content, i.e., a large error in silica content detection.

[0004] Furthermore, this processing method cannot effectively distinguish between elemental silicon (Si) and silicon dioxide (SiO2). When detecting the content of unknown silicon, hydrofluoric acid is first used to initially remove silicon dioxide from the sample (but complete removal of silicon dioxide cannot be guaranteed. Gravimetric methods have biases and will affect the subsequent actual calculation of elemental silicon). Then, a mixture of hydrofluoric acid and nitric acid is used for digestion. The liquid is then analyzed using ICP (using a silicon dioxide standard solution in water) to detect the silicon dioxide content, indirectly calculating the silicon content. However, this method cannot distinguish between silicon dioxide and elemental silicon, so the elemental silicon in the sample cannot be qualitatively identified through detection and can only be indirectly inferred through calculation.

[0005] In summary, existing methods for detecting trace amounts of elemental silicon in unknown substances have the following shortcomings: First, most chemical analysis methods require complex sample preparation procedures, reaction processes, and analytical steps, and are prone to side reactions, leading to errors in the detection results; second, the analytical efficiency is low, and the reaction time is long, making it difficult to meet the timeliness requirements of analysis; third, they cannot directly analyze elemental silicon in the sample, but can only detect elemental silicon in the sample through silica detection, resulting in low detection efficiency and poor accuracy.

[0006] The existing methods for detecting trace amounts of elemental silicon in unknown substances have the following shortcomings: First, most chemical analysis methods require complex sample preparation procedures, reaction processes, and analytical steps, and are prone to side reactions, leading to errors in the detection results; Second, the analysis efficiency is low, and the reaction time is long, making it difficult to meet the timeliness requirements of analysis.

[0007] Therefore, there is a need for a device that can qualitatively detect trace amounts of elemental silicon in unknown substances, and that is simple to operate, highly efficient, and has small errors. Summary of the Invention

[0008] To address the problems of complex operation, low efficiency, and large errors in existing methods for detecting trace silicon in unknown substances, this paper proposes a system for the qualitative detection of trace silicon in unknown substances. In this technical solution, the setup of a generator, a sodium hydroxide feeding device, a gas detection device, and a venting device ensures that elemental silicon (Si) reacts with sodium hydroxide (NaOH) to generate gas (hydrogen). By judging the volume change caused by the gas, the trace elemental silicon in the unknown substance is indirectly qualitatively detected. Furthermore, the amount of volume change caused by the gas is used to roughly determine the content of trace elemental silicon, providing a preliminary reference for the quantitative analysis of silicon in unknown samples.

[0009] To achieve the above technical objectives, the following technical solution is proposed:

[0010] The purpose of this technical solution is to provide: a system for detecting trace silicon content in an unknown substance, comprising a generator, a sodium hydroxide feeding device, a gas detection device, and an venting device; wherein,

[0011] Generator: Includes generator body and storage tray inside generator body. The generator body has an opening at the upper end, and a sealing plug for sealing the generator is fitted inside the opening. Preferably, the inner wall of the opening is frosted to increase the sealing between the opening and the sealing plug. The sealing plug is a rubber plug with a certain elasticity, which can better seal the generator body. The sealing plug has through hole I, through hole II and through hole III. The storage tray is a storage tray with adjustable sieve holes.

[0012] More specifically, the storage tray is arranged in two layers, including an upper tray and a lower tray that can rotate relative to the upper tray. The upper tray has multiple sieve holes evenly distributed on it, and the lower tray has multiple sieve holes evenly distributed on it.

[0013] Sodium hydroxide feeding device: includes a feeding hopper and a feeding pipe located at the lower end of the feeding hopper. The upper end of the feeding pipe is connected to the feeding hopper, and the lower end passes through through hole I and the storage tray, extending towards the bottom of the generator. Preferably, the feeding hopper and the feeding pipe are integrally formed (e.g., a long-necked funnel). The lower part of the feeding pipe is fixedly connected to the upper tray, and the lower part of the feeding pipe is movably connected to the lower tray, for example, the lower tray is provided with a sliding sleeve, and the lower part of the feeding pipe is fitted into the sliding sleeve. The above configuration ensures the stability of the unknown sample feeding and facilitates stable and effective rotation of the upper tray, realizing relative rotation between the upper and lower trays, and ultimately adjusting the flow path of the unknown.

[0014] Gas detection device: includes a detection tube and a piston disposed inside the detection tube. The detection tube is marked with graduations. The lower end of the detection tube passes through through hole II and extends into the generator body. The detection tube and through hole II are sealed together. The upper end of the detection tube extends out of the generator body. The piston is sleeved inside the detection tube.

[0015] The venting device includes an air venting pipe, a pipette containing liquid medium, and a liquid tank containing liquid medium. One end of the air venting pipe passes through through hole III and extends into the generator body, with a sealed connection between the air venting pipe and through hole III. The other end of the air venting pipe is connected to the pipette and is equipped with a one-way valve. The end of the pipette extends below the liquid surface in the liquid tank. More specifically, the air venting pipe is L-shaped, and the pipette is U-shaped, with graduations on it. A connecting pipe (preferably a flexible pipe, such as a rubber tube) is provided between the pipette and the liquid tank to facilitate the stable extension of the air venting pipe below the liquid surface in the liquid tank. This configuration facilitates the assembly of the components and ensures, to a certain extent, that the venting device can smoothly, stably, and orderly vent the air from the generator body. By observing the bubbling in the liquid tank and the liquid absorption in the pipette, the air venting status within the generator body can be determined, providing a reference for subsequent operations.

[0016] Furthermore, the detection tube is connected to a gas collection device. When further detection of the type and content of gas within the generator body is required, the gas within the generator body is collected and subjected to corresponding tests to meet the further needs.

[0017] The mechanisms involved in this technical solution include:

[0018] Sodium hydroxide (NaOH) reacts with elemental silicon (Si + 2NaOH + H2O → Na2SiO3 + 2H2↑) to produce silicates and hydrogen gas. Silicates are soluble in water, while hydrogen gas has low density and low solubility. Even a small amount of hydrogen gas can occupy a large volume / space, resulting in a large change in the volume of the space it occupies.

[0019] The positional relationships such as "inner", "upper end", "upper", "lower end", "lower part", "one end", "the other end", and "below" involved in this technical solution are defined according to the actual usage conditions and are conventional terms in this technical field, as well as conventional terms used by those skilled in the art in actual use.

[0020] In the description of this technical solution, it should be noted that, unless otherwise explicitly specified and limited, the terms "setting" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] Compared with the prior art, this utility model has the following advantages and beneficial effects.

[0022] (1) This invention avoids the problem of non-targeted dissolution of elemental silicon caused by the existing method of treating silicon dioxide with HF, which affects the reliability of the results. This invention utilizes the reaction between elemental silicon and sodium hydroxide to directly and qualitatively detect elemental silicon in unknown substances, thereby improving detection efficiency and accuracy;

[0023] (2) This utility model has a simple structure and is easy to operate. It uses a gas generator to heat the sample to react the elemental silicon (Si) with sodium hydroxide (NaOH) to produce hydrogen. The generated hydrogen is collected by a gas collection device connected to a gas detection device (to facilitate chromatographic gas component analysis). After the components are collected, the one-way valve is closed. Then, the volume of hydrogen released by the reaction is determined by the water displacement method, and the elemental silicon content in the sample is roughly calculated.

[0024] (3) The entire system of this utility model is in a relatively closed state, which effectively prevents hydrogen leakage; the main substances present in the qualitative sample, such as aluminum compounds, are difficult to react with alkaline solution, and the results are calculated more accurately; the reaction and gas analysis time of the entire system is greatly shortened from the original 24h to 4h, and the efficiency is increased by 83.33%. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the working principle of this utility model;

[0026] Figure 2 This is an exploded view of the tray in Example 3;

[0027] Figure 3 This is a diagram showing the working state of the tray in Example 3 (I).

[0028] Figure 4This is a diagram showing the working state of the tray in Example 3 (II);

[0029] Among them, 1. generator, 10. generator body, 11. tray, 110. upper plate, 111. lower plate, 12. sieve hole, 13. opening, 14. sealing plug, 15. through hole I, 16. through hole II, 17. through hole III.

[0030] 2. Sodium hydroxide feeding device; 20. Feed hopper; 21. Feed pipe;

[0031] 3. Gas detection device; 30. Detection tube; 31. Piston;

[0032] 4. Venting device; 40. Air vent pipe; 41. Pipette; 42. Liquid tank; 43. Check valve; 44. Connecting pipe.

[0033] Figure 2-4 The dotted shaded areas are for illustrative purposes only and do not constitute a limitation on the equipment structure. Detailed Implementation

[0034] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0035] Example 1

[0036] This embodiment provides a system for detecting trace silicon content in an unknown substance, such as... Figure 1 As shown, it includes a generator 1, a sodium hydroxide feeding device 2, a gas detection device 3, and an venting device 4;

[0037] Generator 1: includes generator body 10 and storage tray 11 disposed inside generator body 10. Generator body 10 has an opening 13 at the upper end, and a sealing plug 14 for sealing generator 1 is sleeved inside the opening 13. The sealing plug 14 has through hole I 15, through hole II 16 and through hole III 17. Storage tray 11 is a storage tray with adjustable sieve holes 12.

[0038] Sodium hydroxide feeding device 2: includes a feeding hopper 20 and a feeding pipe 21 located at the lower end of the feeding hopper 20. The upper end of the feeding pipe 21 is connected to the feeding hopper 20, and the lower end passes through the through hole I15 and the storage plate 11, extending towards the bottom of the generator 1.

[0039] Gas detection device 3: includes a detection tube 30 and a piston 31 disposed inside the detection tube 30. The detection tube 30 is provided with a scale. The lower end of the detection tube 30 passes through the through hole II 16 and extends into the generator body 10. The detection tube 30 and the through hole II 16 are sealed together. The upper end of the detection tube 30 extends outward from the generator body 10. The piston 31 is sleeved inside the detection tube 30.

[0040] The venting device 4 includes an air venting pipe 40, a pipette 41 containing a liquid medium, and a liquid tank 42 containing a liquid medium. One end of the air venting pipe 40 passes through a through hole III 17 and extends into the generator body 10, with a sealed connection between the air venting pipe 40 and the through hole III 17. The other end of the air venting pipe 40 is connected to the pipette 41, and a one-way valve 43 is provided on the air venting pipe 40. The end of the pipette 41 extends below the liquid surface in the liquid tank 42, and the pipette 41 is graduated. The liquid medium is preferably water.

[0041] In this technical solution, by setting up generator 1, sodium hydroxide feeding device 2, gas detection device 3, and venting device 4, the air in generator 1 is vented to a certain extent, so that elemental silicon (Si) reacts with sodium hydroxide (NaOH) to generate hydrogen gas. By judging the volume change caused by hydrogen gas, the trace amount of elemental silicon in the unknown substance is indirectly qualitatively detected. In addition, by judging the amount of volume change caused by hydrogen gas, the content of trace elemental silicon is roughly detected (based on the reaction formula, by back calculation), so as to provide a preliminary reference for the quantitative analysis of silicon in the unknown sample.

[0042] To address the air venting from generator 1, generator 1 can be heated before the elemental silicon (Si) contacts / reacts with sodium hydroxide (NaOH) to increase the pressure inside, allowing as much air as possible to escape. Alternatively, the air content (volume) can be kept relatively stable by increasing the system's sealing, thus preventing it from affecting the volume changes caused by the newly generated hydrogen gas after the reaction. This improves the accuracy of qualitative detection of elemental silicon and reduces errors.

[0043] Example 2

[0044] Based on Example 1, this example further limits the structure of generator 1 to ensure the airtightness of generator 1. This is done to allow for the maximum possible expulsion of air before detection and to prevent outside air from re-entering generator 1. Additionally, it prevents leakage of hydrogen generated during detection, thus ensuring the validity of hydrogen volume measurement.

[0045] In generator 1, the inner wall of the opening 13 is provided with abrasive to increase the sealing between the opening 13 and the sealing plug 14.

[0046] The sealing plug 14 involved is a rubber plug, which has a certain elasticity. It can not only increase the sealing between the sealing plug 14 and the opening 13 on the generator body 10, but also increase the sealing between the sealing plug 14 and the feed pipe 21 (corresponding to through hole I 15), the detection pipe 30 (corresponding to through hole II 16), and the air exhaust pipe 40 (corresponding to through hole III 17).

[0047] Example 3

[0048] Based on embodiments 1-2, this embodiment, as a specific implementation, proposes a specific structure for a storage tray 11 with adjustable sieve holes 12:

[0049] like Figure 2-4 As shown, the storage tray 11 is arranged in a double layer. The storage tray 11 includes an upper tray 110 and a lower tray 111 that can rotate relative to the upper tray 110. The upper tray 110 has multiple sieve holes 12 (denoted as sieve holes 12Ⅰ) evenly distributed on it, and the lower tray 111 has multiple sieve holes 12 (denoted as sieve holes 12Ⅱ) evenly distributed on it. By rotating the lower tray 111, the positions of sieve holes 12Ⅰ and sieve holes 12Ⅱ can be adjusted to achieve alignment / misalignment / partial alignment of sieve holes 12Ⅰ with sieve holes 12Ⅱ, and finally adjust the size of the flow path of the unknown substance. It is applicable to unknown substance samples of different particle sizes (block, granular, powder, etc.), expanding the application scenarios. At the same time, it is convenient to control the addition of unknown substance samples when needed, ensuring the controllability of the contact and reaction between the unknown substance sample and sodium hydroxide.

[0050] By further refining the structure of the placement tray 11, it is easier for staff to operate. For example, after assembling the system and placing the unknown sample on the placement tray 11 (at this time, the sieve hole 12Ⅰ is not aligned with the sieve hole 12Ⅱ, and the unknown sample cannot fall through the sieve hole 12 to the bottom of the generator body 10), the staff first opens the one-way valve 43. Through heating, the air inside the generator 1 is discharged through the air vent pipe 40 and the pipette 41. When no bubbles are bubbling out in the liquid tank 42 (no bubbles are rising) and / or the liquid in the pipette 41 shows obvious displacement (liquid absorption), it indicates that the air inside the generator 1 has been discharged to a stable state. At this time, according to actual needs, sodium hydroxide can be injected into the reactor through the feeding hopper 20 first, and then the feed pipe 21 can be rotated to adjust the sieve hole 12Ⅰ to align with the sieve hole 12Ⅱ, that is, the unknown sample is added to the lower part of the generator body 10. The unknown sample comes into contact with the sodium hydroxide and reacts.

[0051] Example 4

[0052] Based on Examples 1-3, this example further defines the structure of the sodium hydroxide feeding device 2 to further illustrate the technical solution.

[0053] The feeding hopper 20 and the feed pipe 21 are integrally formed, such as a long-necked funnel. The lower part of the feed pipe 21 is fixedly connected to the upper plate, and the lower part of the feed pipe 21 is movably connected to the lower plate 111. This design improves the overall structural integrity of the sodium hydroxide feeding device 2, ensures the stability of the unknown sample feeding, and facilitates stable and effective rotation of the upper plate, enabling relative rotation between the upper and lower plates and ultimately adjusting the flow path of the unknown. To achieve the movable connection between the feed pipe 21 and the lower plate 111, a sliding sleeve can be provided on the lower plate 111, with the lower part of the feed pipe 21 fitted inside the sleeve. More specifically, the sliding sleeve is fixedly mounted on the lower plate 111, allowing the feed pipe 21 to slide relative to the sleeve.

[0054] Based on the purpose and application scenario of this technical solution, other mature existing technologies that can achieve the movable connection between the feed pipe 21 and the lower plate 111 can also be adopted.

[0055] Example 5

[0056] Based on embodiments 1-4, this embodiment further defines the structure of the venting device 4 to further illustrate the technical solution.

[0057] In the venting device 4, the air venting pipe 40 is L-shaped, and the pipette 41 is U-shaped with graduations. A connecting pipe 44 (preferably a flexible pipe, such as a rubber tube) is provided between the pipette 41 and the liquid tank 42 to facilitate the stable extension of the air venting pipe 40 to below the liquid surface in the liquid tank 42. This arrangement facilitates the assembly of the components and ensures, to a certain extent, that the venting device 4 can smoothly, stably, and orderly vent the air from the generator body 10. By observing the bubbling in the liquid tank 42 and the liquid absorption in the pipette 41, the air venting status in the generator body 10 can be determined, providing a reference for subsequent operations.

[0058] Example 6

[0059] Based on Examples 1-5, this example can further limit the materials and dimensions of the components involved according to actual needs, or add equipment (such as gas collection device, gas detection device 3, etc.) to further achieve air exhaust, and ultimately indirectly achieve qualitative detection of elemental silicon and detection of elemental silicon content.

[0060] For example, the detection tube 30 is connected to the gas collection device. When it is necessary to further detect the type and content of gas in the generator body 10, the gas in the generator body 10 is collected and the corresponding tests are performed to meet the further requirements.

[0061] For example, regarding component size, the appropriate volume can be selected based on the sample quantity. When the unknown sample quantity is 0.5g, theoretical calculations based on the reaction equation of silicon and sodium hydroxide indicate that the hydrogen content is approximately 0.875L. Therefore, a generator body with a volume of 0.5L and a detection tube with a volume of 0.1L are selected. To further verify the accuracy of the detection, the unknown sample can be reacted and detected twice as needed.

[0062] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A system for detecting trace silicon content in an unknown substance, characterized in that: It includes a generator (1), a sodium hydroxide feeding device (2), a gas detection device (3), and an venting device (4); among which, The generator (1) includes a generator body (10) and a tray (11) with a sieve hole (12). The upper end of the generator body (10) is provided with an opening (13). A sealing plug (14) for sealing the generator (1) is fitted inside the opening (13). The sealing plug (14) is provided with a through hole I (15), a through hole II (16) and a through hole III (17). The tray (11) is located inside the generator body (10). The tray (11) is a tray (11) with an adjustable sieve hole (12). The sodium hydroxide feeding device (2) includes a feeding hopper (20) and a feeding pipe (21) located at the lower end of the feeding hopper (20). The upper end of the feeding pipe (21) is connected to the feeding hopper (20), and the lower end passes through the through hole I (15) and the storage plate (11) and extends to the bottom of the generator (1). The gas detection device (3) includes a detection tube (30) and a piston (31) disposed inside the detection tube (30). The detection tube (30) is provided with a scale. The lower end of the detection tube (30) passes through the through hole II (16) and extends into the generator body (10). The detection tube (30) and the through hole II (16) are sealed together. The upper end of the detection tube (30) extends outward from the generator body (10). The piston (31) is fitted inside the detection tube (30). The venting device (4) includes an air venting pipe (40), a pipette (41) containing liquid medium, and a liquid tank (42) containing liquid medium. One end of the air venting pipe (40) passes through the through hole III (17) and extends into the generator body (10). The air venting pipe (40) and the through hole III (17) are sealed together. The other end of the air venting pipe (40) is connected to the pipette (41). A one-way valve (43) is provided on the air venting pipe (40). The end of the pipette (41) extends to below the liquid surface in the liquid tank (42). The pipette (41) is provided with a scale.

2. The system for detecting trace silicon content in an unknown substance according to claim 1, characterized in that: The inner wall of the opening (13) is provided with frosting, and the sealing plug (14) is a rubber plug.

3. The system for detecting trace silicon content in an unknown substance according to claim 1, characterized in that: The storage tray (11) is arranged in two layers. The storage tray (11) includes an upper plate (110) and a lower plate (111) that can rotate relative to the upper plate (110). The upper plate (110) has sieve holes (12) distributed on it, and the lower plate (111) has sieve holes (12) distributed on it.

4. The system for detecting trace silicon content in an unknown substance according to claim 3, characterized in that: The sieve holes (12) are multiple and are evenly distributed on the upper plate (110) and the lower plate (111).

5. The system for detecting trace silicon content in an unknown substance according to claim 3 or 4, characterized in that: The lower part of the feed pipe (21) is fixedly connected to the upper plate, and the lower part of the feed pipe (21) is movably connected to the lower plate (111).

6. The system for detecting trace silicon content in an unknown substance according to claim 5, characterized in that: The lower plate (111) is provided with a sliding sleeve, and the lower part of the feed pipe (21) is sleeved inside the sliding sleeve.

7. The system for detecting trace silicon content in an unknown substance according to claim 6, characterized in that: The feeding hopper (20) and the feeding pipe (21) are integrally formed.

8. The system for detecting trace silicon content in an unknown substance according to claim 1, characterized in that: The air vent pipe (40) is L-shaped, the pipette (41) is U-shaped, and a connecting pipe (44) is provided between the pipette (41) and the liquid tank (42).

9. The system for detecting trace silicon content in an unknown substance according to claim 8, characterized in that: The connecting pipe (44) is a flexible pipe.

10. The system for detecting trace silicon content in an unknown substance according to claim 1, characterized in that: The detection tube (30) is connected to the gas collection device.

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