A method for on-line dynamic monitoring of silicon powder activity

Abstract

The application discloses a kind of silicon powder activity online dynamic monitoring method, comprising the following steps: S1, online monitoring: in the process of fluidized bed operation, a plurality of spectral detectors are used to monitor characteristic parameters;S2, parameter conversion: the intermediate parameter is calculated according to the parameter conversion formula using the characteristic parameters monitored in S1, online monitoring;S3, activity calculation: the real-time activity index of silicon powder in fluidized bed is calculated according to the activity calculation formula using the intermediate parameter calculated in S2, parameter conversion.The advantage is that: the activity condition of silicon powder in fluidized bed can be accurately and real-timely reflected, the accurate calculation of hydroxyl inhibition factor, amorphous phase activity gain and metal impurity inhibition factor and other key parameters provides scientific basis for the evaluation of silicon powder activity, provides control basis for real-time control of feed ratio and other parameters of fluidized bed, optimizes production process, improves product quality, reduces production cost, and brings significant economic benefits to enterprises.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of silicon powder determination, in particular to a method for online dynamic monitoring of the activity of silicon powder. BACKGROUND

[0002] As the core basic material of photovoltaic power generation and semiconductor chips, the high-purity production of polysilicon is a key link in the cutting-edge manufacturing industry. In the mainstream modified Siemens method, silicon powder is the core raw material for synthesizing the core intermediate trichlorosilane (SiHCl3), participating in the chemical conversion of Si+3SiCl4+2H2→4SiHCl3. The reaction efficiency of this step directly determines the output rate and energy consumption level of high-purity silicon, and the activity of silicon powder directly affects the reaction efficiency and the purity of the product. Therefore, the activity of silicon powder is a core indicator for measuring its quality and application effect, and accurate and efficient monitoring of the activity of silicon powder is of great significance for ensuring the quality of downstream products and optimizing the production process.

[0003] Currently, there are few methods for monitoring the activity of silicon powder. In the polysilicon industry, the method for determining the activity of silicon powder based on sodium hydroxide reaction is used. The principle is that silicon powder is used as the raw material, sodium hydroxide solution is used as the reaction liquid, and the reaction is carried out under the condition of high-temperature heating by an electric heating plate. The rate of hydrogen generation during the reaction is monitored to represent the activity of industrial silicon powder. However, the above detection method has the following problems:

[0004] 1. Reaction difference: the reaction activity represented by sodium hydroxide is quite different from the reaction activity of silicon powder under the condition of silicon tetrachloride, so the reaction activity of silicon powder under the condition of silicon tetrachloride cannot be directly obtained from the sodium hydroxide reaction;

[0005] 2. Monitoring lag: offline detection has a lag, and the process parameters (such as H2 / SiCl4 ratio) cannot be adjusted in real time to maximize the reaction rate based on the detection results;

[0006] 3. Large error in indirect calculation: the conversion rate of existing industrial silicon powder is calculated indirectly by the amount of silicon tetrachloride fed and the amount of trichlorosilane discharged, which takes a long time and has a large error, and is easily affected by multiple factors such as temperature, pressure, gas flow, and impurities;

[0007] 4. Actual production conditions are not considered: the actual situation where silicon powder particles are too small to participate in fluidization, causing silicon powder to escape directly and cause system blockage is not considered.

[0008] With the increasing requirements of modern industrial production on the quality control precision and efficiency of raw materials, the traditional offline detection method is difficult to meet the needs of online dynamic monitoring in the production process of silicon powder. At present, the industry urgently needs an online dynamic monitoring method that can quickly, accurately and continuously monitor the activity changes of silicon powder, so as to realize real-time control of the quality of silicon powder, optimize the production process, and reduce the product quality risk caused by the fluctuation of silicon powder activity. SUMMARY

[0009] In order to solve the above problems, the purpose of the present application is to provide a silicon powder activity online dynamic monitoring method to realize online dynamic monitoring of the activity of silicon powder quickly, accurately and continuously.

[0010] The present application is implemented by the following technical solutions:

[0011] A silicon powder activity online dynamic monitoring method, comprising the following steps:

[0012] S1, online monitoring: during the operation of the fluidized bed, a plurality of spectral detectors are used to monitor characteristic parameters;

[0013] S2, parameter conversion: the characteristic parameters monitored in S1, online monitoring are used to calculate intermediate parameters according to a parameter conversion formula;

[0014] S3, activity calculation: the intermediate parameters calculated in S2, parameter conversion are used to calculate the real-time activity index of the silicon powder in the fluidized bed according to an activity calculation formula.

[0015] Further, in S1, online monitoring, the plurality of spectral detectors include a mid-infrared detector, an in-situ Raman spectral detector and a UV-Vis detector.

[0016] Further, in S1, online monitoring, the characteristic parameters include the surface hydroxyl absorbance a (3650cm -1 ), the absorbance of Si-Cl bond a (600cm -1 ), the peak intensity of amorphous silicon phase p (480cm -1 ), the peak intensity of crystal p (520cm -1 ) and the absorbance of surface metal impurities.

[0017] Further, the absorbance of surface metal impurities includes the absorbance of aluminum a (Al).

[0018] Further, the absorbance of surface metal impurities also includes the absorbance of iron a (Fe).

[0019] Further, in S2, parameter conversion, the intermediate parameters include a hydroxyl inhibition factor X1, an amorphous phase activity gain X2 and a metal impurity inhibition factor X3.

[0020] Further, S2, parameter conversion,

[0021] The parameter conversion formula for calculating the hydroxyl inhibition factor X1 is:

[0022]

[0023] The parameter conversion formula for calculating the amorphous phase activity gain X2 is:

[0024]

[0025] The parameter conversion formula for calculating the metal impurity inhibition factor X3 is:

[0026]

[0027] Further, S3, activity calculation, the activity calculation formula for calculating the real-time activity index MAI of the silicon powder in the fluidized bed is:

[0028]

[0029] Wherein, k is the hydroxyl inhibition coefficient, and the value is 1.2.

[0030] Advantages of the present application:

[0031] The present application can accurately and in real time reflect the activity condition of the silicon powder in the fluidized bed, and through the accurate calculation of the key parameters such as the hydroxyl inhibition factor, the amorphous phase activity gain and the metal impurity inhibition factor, a scientific basis is provided for the evaluation of the activity of the silicon powder, and then a control basis is provided for the real-time control of the feeding ratio of the fluidized bed in industrial production, the production process is optimized, the product quality is improved, the production cost is reduced, and significant economic benefits are brought to the enterprise. At the same time, the method also provides a new technical means for the activity monitoring field of the silicon powder, and has wide application prospect and popularization value. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0033] Embodiment 1:

[0034] A silicon powder activity online dynamic monitoring method, the fluidized bed supplier in the embodiment is Zhongsheng Technology, the silicon powder used is 553# silicon powder provided by Hesheng Silicon Industry, the particle size is 93-1800μm; the data recorded in table 1 is the data in a time period monitored after the fluidized bed runs for 6 hours. The specific method comprises the following steps:

[0035] S1, online monitoring: during the operation of the fluidized bed, the surface hydroxyl absorbance a(3650cm -1 ), the absorbance of Si-Cl bond a(600cm -1 ), the peak intensity of amorphous silicon phase p(480cm -1 ), the peak intensity of crystal p(520cm -1 ), the absorbance of aluminum a(Al) and the absorbance of iron a(Fe) are monitored by using the mid-infrared detector, the in-situ Raman spectrum detector and the ultraviolet-visible detector respectively;

[0036] S2, parameter conversion: the surface hydroxyl absorbance a(3650cm -1 ), the absorbance of Si-Cl bond a(600cm -1 ), the peak intensity of amorphous silicon phase p(480cm -1 ), the peak intensity of crystal p(520cm -1 ), the absorbance of aluminum a(Al) and the absorbance of iron a(Fe) monitored in S1, online monitoring are used to calculate the intermediate parameters of hydroxyl inhibition factor X1, amorphous phase activity gain X2 and metal impurity inhibition factor X3 according to the parameter conversion formula; wherein,

[0037] The parameter conversion formula for calculating the hydroxyl inhibition factor X1 is:

[0038]

[0039] The parameter conversion formula for calculating the amorphous phase activity gain X2 is:

[0040]

[0041] The parameter conversion formula for calculating the metal impurity inhibition factor X3 is:

[0042]

[0043] S3, activity calculation: the hydroxyl inhibition factor X1, the amorphous phase activity gain X2 and the metal impurity inhibition factor X3 calculated in S2, parameter conversion are used to calculate the real-time activity index of the silicon powder in the fluidized bed according to the activity calculation formula ; the activity calculation formula is:

[0044]

[0045] wherein k is a hydroxyl inhibition factor, and has a value of 1.2.

[0046] Table 1: Data statistics table of Example 1

[0047]

[0048] Example 2:

[0049] The difference between this example and Example 1 is only that the silicon powder used is 99# silicon powder provided by Hesheng Silicon Industry, with a particle size of 93-1800 μm; the data recorded in Table 2 are the data of each item monitored in a time period after the fluidized bed has been running for 0.5 hours.

[0050] Table 2: Data statistics table of Example 2

[0051]

[0052] Example 3:

[0053] The difference between this example and Example 1 is only that the data recorded in Table 3 are the data of each item monitored in a time period after the fluidized bed has been running for 1 hour.

[0054] Table 3: Data statistics table of Example 3

[0055]

[0056] 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 by the method of the present application, the data are relatively stable and do not have large fluctuations, indicating that the silicon powder activity online dynamic monitoring method provided by the present application has high stability and reliability. The method can accurately and in real time reflect the activity status of the silicon powder in the fluidized bed, and through accurate calculation of key parameters such as the hydroxyl inhibition factor, amorphous phase activity gain and metal impurity inhibition factor, provides a scientific basis for the evaluation of the activity of the silicon powder. In Examples 1, 2 and 3, although the source of the silicon powder, monitoring time and other conditions are different, the calculated activity index can remain relatively stable, which further verifies the effectiveness and adaptability of the method in practical application. In industrial production, the feeding ratio of the fluidized bed and other conditions can be real-time regulated according to the silicon powder activity index calculated by the present application, thereby optimizing the production process, improving product quality, reducing production cost, and bringing significant economic benefits to the enterprise. At the same time, the method also provides a new technical means for the field of silicon powder activity monitoring, and has broad application prospects and promotional value.

[0057] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for on-line dynamic monitoring of the activity of silicon powder, characterized in that, The method comprises the following steps: S1, online monitoring: during the operation of the fluidized bed, a plurality of spectral detectors are used to monitor characteristic parameters; the characteristic parameters include surface hydroxyl absorbance a(3650cm -1 ), Si-Cl bond absorbance a(600cm -1 ), peak intensity p(480cm -1 ) of amorphous silicon phase, peak intensity p(520cm -1 ) of crystal and surface metal impurity absorbance; S2, parameter conversion: calculating intermediate parameters according to a parameter conversion formula by using the characteristic parameters monitored in S1, online monitoring; the intermediate parameters comprise a hydroxyl inhibition factor X1, an amorphous phase activity gain X2, and a metal impurity inhibition factor X3; S3, activity calculation: calculating a 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 S2, parameter conversion; The activity calculation formula for calculating the real-time activity index MAI of the silicon powder in the fluidized bed is as follows: wherein k is a hydroxyl inhibition coefficient, and the value is 1.

2.

2. The method according to claim 1, wherein, In S1, online monitoring, the multiple spectral detectors comprise a mid-infrared detector, an in-situ Raman spectral detector, and a UV-Vis detector.

3. The method according to claim 1, wherein the silicon powder activity is monitored on-line dynamically. The absorbance of the surface metal impurities comprises an absorbance of aluminum a(Al).

4. The method according to claim 3, wherein the silicon powder activity is monitored on-line. The absorbance of the surface metal impurities further comprises an absorbance of iron a(Fe).

5. The method of claim 1, wherein the silicon powder activity is monitored on-line dynamically. In S2, parameter conversion, The parameter conversion formula for calculating the hydroxyl inhibition factor X1 is as follows: The parameter conversion formula for calculating the amorphous phase activity gain X2 is as follows: The parameter conversion formula for calculating the metal impurity inhibition factor X3 is as follows: 。

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