Online dynamic monitoring method for activity of silicon powder

Abstract

The invention discloses a silicon powder activity on-line dynamic monitoring method, which comprises the following steps: S1, on-line monitoring: monitoring characteristic parameters by using a plurality of spectrum detectors in the operation process of a fluidized bed; s2, parameter conversion: calculating intermediate parameters according to a parameter conversion formula by utilizing the characteristic parameters monitored in the step S1 in the online monitoring; and S3, activity calculation: calculating the real-time activity index of the silicon powder in the fluidized bed according to an activity calculation formula by using the intermediate parameters calculated in the step S2. The method has the advantages that the activity condition of the silicon powder in the fluidized bed can be accurately reflected in real time, and a scientific basis is provided for evaluating the activity of the silicon powder by accurately calculating key parameters such as a hydroxyl inhibition factor, an amorphous phase activity gain and a metal impurity inhibition factor; a regulation and control basis is provided for real-time regulation and control of the feeding proportion and the like of the fluidized bed, the production process is optimized, the product quality is improved, the production cost is reduced, and remarkable economic benefits are brought to enterprises.

Description

Technical Field

[0001] This invention relates to the field of silicon powder determination, and specifically to a method for online dynamic monitoring of silicon powder activity. Background Technology

[0002] Polycrystalline silicon, as a core material for photovoltaic power generation and semiconductor chips, requires high-purity production, a crucial step in advanced manufacturing. In the dominant modified Siemens process, silicon powder is the key raw material for synthesizing the core intermediate—trichlorosilane (SiHCl3), participating in the chemical transformation Si + 3SiCl4 + 2H2 → 4SiHCl3. The reaction efficiency of this step directly determines the yield and energy consumption of subsequent high-purity silicon, while the activity of silicon powder directly affects the reaction efficiency and product purity. Therefore, silicon powder activity is a core indicator for evaluating its quality and application performance; accurate and efficient monitoring of silicon powder activity is of great significance for ensuring the quality of downstream products and optimizing production processes. Currently, there are few methods for monitoring the activity of silicon powder. In the polysilicon industry, the method based on the sodium hydroxide reaction is used to determine the activity of silicon powder. The principle is as follows: using silicon powder as the raw material and sodium hydroxide solution as the reaction liquid, the reaction is carried out under high-temperature heating conditions on an electric heating plate. The rate of hydrogen gas generation during the reaction is monitored to characterize the activity of industrial silicon powder. However, the above detection method has the following problems: 1. Differences in reaction: The reaction activity of silicon powder under silicon tetrachloride conditions is significantly different when using sodium hydroxide to characterize the reaction activity. Therefore, the reaction activity of silicon powder under silicon tetrachloride conditions cannot be directly obtained from the reaction of sodium hydroxide. 2. Monitoring lag: Offline detection has a lag, making it impossible to adjust process parameters (such as the H2 / SiCl4 ratio) in real time based on the detection results to ensure the reaction rate is maximized; 3. Large indirect calculation error: The current industrial silicon powder conversion rate is calculated indirectly by using the feed rate of silicon tetrachloride and the output rate of trichlorosilane. This process takes a long time, has a large error, and is easily affected by multiple factors such as temperature, pressure, airflow, and impurities. 4. Failure to consider actual production conditions: The actual situation was not taken into account that the silicon powder particles were too small to participate in fluidization, and the silicon powder escaped directly, causing system blockage after entering the system. As modern industrial production demands increasingly higher precision and efficiency in raw material quality control, traditional offline detection methods are insufficient to meet the needs of online dynamic monitoring during silicon powder production. Currently, the industry urgently requires an online dynamic monitoring method capable of rapidly, accurately, and continuously monitoring changes in silicon powder activity to achieve real-time control of silicon powder quality, thereby optimizing production processes and reducing product quality risks caused by fluctuations in silicon powder activity. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide an online dynamic monitoring method for silicon powder activity, enabling rapid, accurate, and continuous online dynamic monitoring of silicon powder activity.

[0004] This invention is implemented by the following technical solution: A method for online dynamic monitoring of silicon powder activity includes the following steps: S1. Online monitoring: During the operation of the fluidized bed, multiple spectral detectors are used to monitor the characteristic parameters; S2, Parameter Conversion: Calculate intermediate parameters using the characteristic parameters monitored in S1, online monitoring, and the parameter conversion formula. S3, Activity Calculation: The intermediate parameters obtained in S2, Parameter Conversion are used to calculate the real-time activity index of silicon powder in the fluidized bed according to the activity calculation formula.

[0005] Furthermore, in S1, the online monitoring system includes multiple spectral detectors, including a mid-infrared detector, an in-situ Raman spectral detector, and an ultraviolet-visible detector.

[0006] Furthermore, in S1, during online monitoring, characteristic parameters include the surface hydroxyl absorbance a (3650 cm⁻¹). -1 ), Absorbance a of Si-Cl bond (600cm) -1 Peak intensity p (480 cm⁻¹) of amorphous silicon phase -1 Peak intensity p of the crystal (520 cm⁻¹) -1 (and the absorbance of surface metallic impurities).

[0007] Furthermore, the absorbance of surface metallic impurities includes the absorbance of aluminum, a (Al).

[0008] Furthermore, the absorbance of surface metallic impurities also includes the absorbance of iron, a (Fe).

[0009] Furthermore, in S2 and parameter conversion, the intermediate parameters include hydroxyl inhibition factor X1, amorphous phase activity gain X2, and metal impurity inhibition factor X3.

[0010] Furthermore, in the S2 parameter conversion, The formula for converting parameters for calculating the hydroxyl inhibitor X1 is as follows:

[0011] The parameter conversion formula for calculating the amorphous phase activity gain X2 is as follows:

[0012] The formula for calculating the parameter conversion of the metal impurity inhibition factor X3 is as follows:

[0013] Furthermore, in S3, the activity calculation formula for calculating the real-time activity index (MAI) of silicon powder in the fluidized bed is as follows:

[0014] Where k is the hydroxyl inhibition coefficient, with a value of 1.2.

[0015] Advantages of this invention: This invention accurately and in real-time reflects the activity status of silicon powder in a fluidized bed. Through precise calculation of key parameters such as hydroxyl group inhibition factor, amorphous phase activity gain, and metal impurity inhibition factor, it provides a scientific basis for evaluating silicon powder activity. Furthermore, it provides a basis for real-time control of fluidized bed feed ratios in industrial production, optimizing production processes, improving product quality, and reducing production costs, bringing significant economic benefits to enterprises. Simultaneously, this method also provides a new technical means for monitoring silicon powder activity, with broad application prospects and promotional value. Detailed Implementation The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1: A method for online dynamic monitoring of silicon powder activity is disclosed in this embodiment. The fluidized bed supplier is Zhong Sheng Technology, and the silicon powder used is 553# silicon powder provided by Hesheng Silicon Industry, with a particle size of 93-1800μm. The data recorded in Table 1 are various data monitored within a time period after the fluidized bed has been running for 6 hours. The specific method includes the following steps: S1. Online monitoring: During fluidized bed operation, the surface hydroxyl absorbance a (3650 cm⁻¹) is monitored using a mid-infrared detector, an in-situ Raman spectroscopy detector, and an ultraviolet-visible detector, respectively. -1 ), Absorbance a of Si-Cl bond (600cm) -1 Peak intensity p (480 cm⁻¹) of amorphous silicon phase -1 Peak intensity p of the crystal (520 cm⁻¹) -1 ) as well as the absorbance a(Al) of aluminum and the absorbance a(Fe) of iron; S2, Parameter Conversion: Using the surface hydroxyl absorbance a (3650cm²) monitored in online monitoring as measured in S1, -1 ), Absorbance a of Si-Cl bond (600cm) -1 Peak intensity p (480 cm⁻¹) of amorphous silicon phase -1Peak intensity p of the crystal (520 cm⁻¹) -1 The absorbance a(Al) of aluminum and the absorbance a(Fe) of iron were used to calculate the intermediate parameters X1 (hydroxyl inhibition factor), X2 (amorphous phase activity gain), and X3 (metal impurity inhibition factor) based on the parameter conversion formula; among which, The formula for converting parameters for calculating the hydroxyl inhibitor X1 is as follows:

[0017] The parameter conversion formula for calculating the amorphous phase activity gain X2 is as follows:

[0018] The formula for calculating the parameter conversion of the metal impurity inhibition factor X3 is as follows:

[0019] S3. Activity Calculation: Using the hydroxyl group inhibition factor X1, amorphous phase activity gain X2, and metal impurity inhibition factor X3 obtained in S2 and parameter conversion, the real-time activity index of silicon powder in the fluidized bed is calculated according to the activity calculation formula. The formula for calculating activity is:

[0020] Where k is the hydroxyl inhibition coefficient, with a value of 1.2.

[0021] Table 1. Statistical data of Example 1

[0022] Example 2: The only difference between this embodiment and Embodiment 1 is that the silicon powder used is 99# silicon powder provided by Hoshine Silicon Industry, with a particle size of 93-1800μm; the data recorded in Table 2 are the data monitored over a period of time after the fluidized bed has been running for 0.5 hours.

[0023] Table 2. Data statistics table for Example 2

[0024] Example 3: The only difference between this embodiment and Embodiment 1 is that the data recorded in Table 3 are data from a time period monitored after the fluidized bed has been running for 1 hour.

[0025] Table 3. Statistical data of Example 3

[0026] As can be seen from the monitoring parameters recorded in Examples 1, 2, and 3 shown in Tables 1, 2, and 3, and the silicon powder activity index calculated using the method of this invention, the data are relatively stable without significant fluctuations, indicating that the online dynamic monitoring method for silicon powder activity provided by this invention has high stability and reliability. This method can accurately and in real-time reflect the activity status of silicon powder in a fluidized bed. Through precise calculation of key parameters such as hydroxyl inhibitory factor, amorphous phase activity gain, and metal impurity inhibitory factor, it provides a scientific basis for evaluating silicon powder activity. In Examples 1, 2, and 3, although the silicon powder source and monitoring time differed, the calculated activity index remained relatively stable, further verifying the effectiveness and adaptability of this method in practical applications. In industrial production, the silicon powder activity index calculated according to this invention can be used to control the feed ratio of the fluidized bed in real time, thereby optimizing the production process, improving product quality, and reducing production costs, bringing significant economic benefits to enterprises. At the same time, this method also provides a new technical means for silicon powder activity monitoring, with broad application prospects and promotional value. The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for online dynamic monitoring of silicon powder activity, characterized in that, Includes the following steps: S1. Online monitoring: During the operation of the fluidized bed, multiple spectral detectors are used to monitor the characteristic parameters; S2, Parameter Conversion: Calculate intermediate parameters using the characteristic parameters monitored in S1, online monitoring, and the parameter conversion formula. S3, Activity Calculation: The intermediate parameters obtained in S2, Parameter Conversion are used to calculate the real-time activity index of silicon powder in the fluidized bed according to the activity calculation formula.

2. The method for online dynamic monitoring of silicon powder activity according to claim 1, characterized in that, S1. In online monitoring, multiple spectral detectors are used, including a mid-infrared detector, an in-situ Raman spectral detector, and an ultraviolet-visible detector.

3. The method for online dynamic monitoring of silicon powder activity according to claim 1, characterized in that, S1. In online monitoring, characteristic parameters include surface hydroxyl absorbance a (3650 cm⁻¹). -1 ), Absorbance a of Si-Cl bond (600cm) -1 Peak intensity p (480 cm⁻¹) of amorphous silicon phase -1 Peak intensity p of the crystal (520 cm⁻¹) -1 (and the absorbance of surface metallic impurities).

4. The method for online dynamic monitoring of silicon powder activity according to claim 3, characterized in that, The absorbance of surface metallic impurities includes the absorbance of aluminum, a (Al).

5. The method for online dynamic monitoring of silicon powder activity according to claim 4, characterized in that, The absorbance of surface metallic impurities also includes the absorbance of iron, a (Fe).

6. The method for online dynamic monitoring of silicon powder activity according to claim 5, characterized in that, S2. In the parameter conversion, the intermediate parameters include hydroxyl inhibition factor X1, amorphous phase activity gain X2, and metal impurity inhibition factor X3.

7. The method for online dynamic monitoring of silicon powder activity according to claim 6, characterized in that, S2, during parameter conversion The formula for converting parameters for calculating the hydroxyl inhibitor X1 is as follows: The parameter conversion formula for calculating the amorphous phase activity gain X2 is as follows: The formula for calculating the parameter conversion of the metal impurity inhibition factor X3 is as follows: 。 8. The method for online dynamic monitoring of silicon powder activity according to claim 6, characterized in that, S3. In the activity calculation, the formula for calculating the real-time activity index (MAI) of silicon powder in the fluidized bed is as follows: Where k is the hydroxyl inhibition coefficient, with a value of 1.2.

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