Deslagging method for polycrystalline silicon production process and application thereof

Abstract

The invention relates to the field of polycrystalline silicon production, and discloses a deslagging method for a polycrystalline silicon production process and application of the deslagging method. By predicting the mass N of the silicon powder of the slag slurry, the slag discharge amount Y of the polycrystalline silicon production process can be accurately obtained, and by applying the slag discharge method to the polycrystalline silicon production process, the stability of the polycrystalline silicon production process and the excellent performance of a final product can be ensured.

Description

Technical Field

[0001] The present invention relates to the field of polysilicon production, and particularly to a slag discharging method and its application in the polysilicon production process. Background Art

[0002] In the process of producing polysilicon by the improved Siemens method, the need for slag discharging is inevitable. This is mainly because after the metallurgical grade silicon (99% purity) undergoes the cold hydro - chlorination reaction, about 30% of the elemental silicon is converted into chlorosilane products, and at the same time, some by - products are generated, such as high - boiling substances like hexachloro - disilane and hexachloro - disiloxane. The remaining silicon powder and metal impurities need to formulate a slag discharging strategy to remove the silicon powder and metal impurities whose activity and particle size do not meet the requirements from the system, so as to ensure the quality requirements of the terminal polysilicon product.

[0003] In the existing slag discharging process of producing polysilicon by the improved Siemens method, it is mainly achieved through a large number of cyclone separators for slag discharging and slurry slag discharging, and combined with technical means such as adsorption, rectification, or chemical complexation separately set in each section. For example, in a general production process, cyclone separators are installed inside the fluidized bed in the cold hydro - chlorination section. Mainly, part of the silicon powder with large particle size is returned to the fluidized bed to achieve the efficient utilization of silicon powder. At the same time, cyclone separators are set in the part of the fluidized bed synthesis gas heat recovery. The silicon powder not captured by the cyclone separators will be removed through wet spray dust removal in the subsequent quench tower and sent to the slurry section from the bottom of the quench tower as slurry for chlorosilane recovery and impurity discharge. The waste silicon powder generated in other sections will also be discharged from the system continuously or intermittently, including the outer - rotating silicon powder, slurry silicon powder, maintenance silicon powder, and slag - discharging silicon powder in the chlor - alkali synthesis system, tail - gas silicon powder in the tail - gas system, reduction silicon powder in the reduction system, etc. A large amount of metal impurities mainly composed of iron, aluminum, and calcium are carried in the above - mentioned slag - discharging silicon powder.

[0004] Therefore, in order to avoid the cyclic accumulation of metal impurities during the production process and ensure the stable operation of the production device, a special slag - discharging plan needs to be formulated before starting up. However, the current slag - discharging plan cannot cope with the problems of unstable production process and poor final product quality caused by fluctuations in the silicon powder raw materials. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems that the existing slag - discharging plan cannot cope with the unstable production process and poor final product quality caused by fluctuations in the silicon powder raw materials, and to provide a slag - discharging method for the polysilicon production process, which can ensure the stability of the polysilicon production process and the better quality of the final product.

[0006] To achieve the above purpose, on the one hand, the present invention provides a slag - discharging method for the polysilicon production process, which includes: performing slag - discharging treatment on the polysilicon production slurry to obtain slag - discharging silicon powder; the slag - discharging amount Y of the slag - discharging treatment is determined according to formula (1);

[0007] Among them, k is any value in the range of 0.3 - 1.0, a is any value in the range of -1 to 1, and b is any value in the range of -0.1 to 5;

[0008] Q is the metal impurity treatment capacity value of the polysilicon production system at T=(t a , t c ), and Q = q(A - B - C), where q is any value in the range of 0.7 - 1.3; A is the mass of metal impurities in the raw material silicon powder at T=(t a , t c ), B is the total mass of metal impurities in the outer-rotating silicon powder and the slurry silicon powder at T=(t a , t c ), and C is the total mass of metal impurities in the discharged silicon powder other than B at T=(t a , t c ); and the units of A, B, C, and Q are tons;

[0009] B' is the total mass of metal impurities in the outer-rotating silicon powder and the slurry silicon powder at T=(t b , t c ), C' is the total mass of metal impurities in the discharged silicon powder other than B' at T=(t b , t c ), M is the mass of metal impurities in the slurry silicon powder at T=(t b , t c ), N is the mass of the slurry silicon powder at T=(t b , t c ), and O is the mass of metal impurities in the outer-rotating silicon powder at T=(t b , t c ); and the units of B', C', M, N, and O are tons;

[0010] In addition, the mass O of metal impurities in the outer-rotating silicon powder is determined according to Equation (2);

[0011] Equation (2): O = c×10 d P 2 +eP - f;

[0012] Among them, P is the mass of the discharged outer-rotating silicon powder, and the unit is Kg / time; c is any value in the range of -3.0 to 1.0, d is any value in the range of -7 to -4, e is any value in the range of 0.005 - 0.200, and f is any value in the range of 1 - 90.

[0013] The second aspect of the present invention provides the application of the slag discharging method of the polysilicon production process described in the first aspect of the present invention in the field of polysilicon production.

[0014] Through the above technical solutions, it is possible to achieve refined production of polysilicon, cope with the incoming material fluctuations that may occur during the production process and the changes in the quality requirements of end products, and ensure the quality of polysilicon products and the stable operation of the overall production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the whole-plant silicon powder in the polysilicon production process. DETAILED DESCRIPTION OF THE INVENTION

[0016] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0017] On the one hand, the present invention provides a slag discharging method for a polysilicon production process, the method comprising: discharging the polysilicon production slurry to obtain slurry silicon powder; the slag discharging amount Y of the slag discharging treatment is determined according to formula (1);

[0018] wherein, k is any value in 0.3 - 1.0, a is any value in -1 to 1, and b is any value in -0.1 to 5;

[0019] Q is the metal impurity treatment capacity value of the polysilicon production system at T=(t a , t c ) and Q = q(A - B - C), q is any value in 0.7 - 1.3; A is the mass of metal impurities in the raw material silicon powder at T=(t a , t c ), B is the total mass of metal impurities in the outer-rotating silicon powder and the slurry silicon powder at T=(t a , t c ), C is the total mass of metal impurities in the externally discharged silicon powder other than B at T=(t a , t c ); and the units of A, B, C, and Q are tons;

[0020] B' is the total mass of metal impurities in the outer-rotating silicon powder and the slurry silicon powder at T=(t b , t c ), C' is the total mass of metal impurities in the externally discharged silicon powder other than B' at T=(t b , t c ), M is the mass of metal impurities in the slurry silicon powder at T=(t b , t c ), N is the mass of metal impurities in the slurry silicon powder at T=(t b , t c) mass of the slag pulp silicon powder at that time, and O is the mass of the metal impurities in the outer-rotating silicon powder at T=(t b , t c ); and the units of B', C', M, N, and O are tons;

[0021] Moreover, the mass O of the metal impurities in the outer-rotating silicon powder is determined according to Equation (2);

[0022] Equation (2): O = c×10 d P 2 + eP - f;

[0023] where P is the mass of the externally discharged outer-rotating silicon powder, with the unit of Kg / time; c is any value from -3.0 to 1.0, d is any value from -7 to -4, e is any value from 0.005 to 0.200, and f is any value from 1 to 90.

[0024] In the present invention, preferably, the value Q of the metal impurity treatment capacity of the polysilicon production system at T=(t a , t c ) refers to: the value of the metal impurity treatment capacity of the polysilicon production system during the stage from t a to t c . The present invention does not limit the cycle of the stage from t a to t c . For example, the stage from t a to t c can be 1 month, 2 months, 3 months, etc.

[0025] In the present invention, preferably, the corresponding parameter at T=(t b , t c ), for example, the mass N of the slag pulp silicon powder at T=(t b , t c ) refers to: the mass of the slag pulp silicon powder during the stage from t b to t c . The present invention also does not limit the cycle of the stage from t b to t c . It can be understood that the stage from t a to t c should include the stage from t b to t c .

[0026] In the present invention, regarding the remaining parameters at T=(t a , t c ) or T=(t b , t c ), the meaning is consistent with the above content, and the present invention will not elaborate here.

[0027] In the present invention, it can be understood that the units between the various parameters should match each other. For example, when the unit of Q is tons per month, the units of the remaining parameters should also be consistent.

[0028] In the present invention, the value Q of the metal impurity treatment capacity of the polysilicon production system can be obtained by constructing a mass conservation model of the metal impurities in the whole plant. In a preferred case, q is any value in the range of 0.8 - 1.2.

[0029] In the present invention, in a preferred case, the metal impurities in the silicon powder include iron, aluminum, and calcium.

[0030] In the present invention, to improve the efficiency of the slag discharge method, after classifying the metal impurities, the treatment capacity value Q of iron in the polysilicon production system is also classified. In a preferred case, when T=(t a , t c ), the treatment capacity value of iron in the polysilicon production system is Q_iron, and Q_iron = q(A_iron - B_iron - C_iron);

[0031] When T=(t a , t c ), the treatment capacity value of aluminum in the polysilicon production system is Q_aluminum, and Q_aluminum = q(A_aluminum - B_aluminum - C_aluminum);

[0032] When T=(t a , t c ), the treatment capacity value of calcium in the polysilicon production system is Q_calcium, and Q_calcium = q(A_calcium - B_calcium - C_calcium);

[0033] Wherein, A_iron, A_aluminum, and A_calcium are respectively the masses of the metal impurities iron, aluminum, and calcium in the raw material silicon powder when T=(t a , t c ); B_iron, B_aluminum, and B_calcium are respectively the masses of iron, aluminum, and calcium in the outer-rotating silicon powder and the slurry silicon powder when T=(t a , t c ); C_iron, C_aluminum, and C_calcium are respectively the masses of the metal impurities iron, aluminum, and calcium in the outer-discharged silicon powder except B when T=(t a , t c ); the units of A_iron, A_aluminum, A_calcium, B_iron, B_aluminum, B_calcium, C_iron, C_aluminum, and C_calcium are tons, for example, it can be tons per month.

[0034] In the present invention, in a preferred case, when T=(t b , t c ), the total mass of iron in the outer-rotating silicon powder and the slurry silicon powder is B'_iron, and B'_iron = A_iron - C'_iron - Q_iron;

[0035] When T=(t b , t c) When the total mass of iron and aluminum in the externally rotated silicon powder and the slurry silicon powder is B’aluminum, and B’aluminum = A’aluminum - C’aluminum - Q’aluminum;

[0036] Define T = (t b , t c ) When the total mass of calcium in the externally rotated silicon powder and the slurry silicon powder is B’calcium, and B’calcium = A’calcium - C’calcium - Q’calcium;

[0037] Among them, C_iron, C_aluminum, and C_calcium are the masses of metal impurities iron, aluminum, and calcium in the externally discharged silicon powder other than B’ at T = (t b , t c ); The units of B’_iron, B’_aluminum, B’_calcium, C’_iron, C’_aluminum, and C’_calcium are tons, for example, it can be tons / month.

[0038] In the present invention, the inventor found that a regression analysis of the masses of iron, aluminum, and calcium in the slurry silicon powder and the mass of the slurry silicon powder can be constructed. Preferably, define T = (t b , t c ) When the masses of iron, aluminum, and calcium in the slurry silicon powder are M_iron, M_aluminum, and M_calcium respectively; and, M_iron, M_aluminum, and M_calcium are determined by the following formulas;

[0039] (Equation 3-1): M_iron = 0.1732N1 + 3.4085;

[0040] (Equation 3-2): M_aluminum = 0.0139N2 + 3.4936;

[0041] (Equation 3-3): M_calcium = 0.0183N3 - 0.0851;

[0042] Among them, N1, N2, and N3 are all the masses of the slurry silicon powder at T = (t b , t c );

[0043] In the present invention, preferably, define the mass of the slurry silicon powder at T = (t b , t c ) to be calculated according to the following formula:

[0044] Equation (3):

[0045] In the present invention, the inventor found that a regression analysis of the masses of iron, aluminum, and calcium in the externally rotated silicon powder and the mass of the externally rotated silicon powder can be constructed. Preferably, define T = (t b , t c ) When the masses of iron, aluminum, and calcium in the externally rotated silicon powder are O_iron, O_aluminum, and O_calcium respectively; and, O_iron, O_aluminum, and O_calcium are determined by the following formulas;

[0046] (Equation 4-1): O_iron = -1.514×10-5 P 2 +0.1435P - 72.120;

[0047] (Equation 4 - 2): O_aluminum = -2.480×10 -6 P 2 +0.0165P - 16.723;

[0048] (Equation 4 - 3): O_calcium = -0.960×10 -6 P 2 +0.0112P - 4.873.

[0049] In the present invention, the metal impurities in the raw material silicon powder may include: the metal impurities in the raw material silicon powder of the cold hydrogenation process and the metal impurities in the raw material silicon powder of the chlor - alkali process.

[0050] In the present invention, preferably, the values of each parameter may be the average values within the corresponding stage.

[0051] In the present invention, preferably, the metal impurities C in the discharged silicon powder except B or the metal impurities C' in the discharged silicon powder except B' include: the metal impurities in the tail gas silicon powder, the reduced silicon powder, the finished product silicon metal impurities, the maintenance silicon powder metal impurities, and the slag - discharging silicon powder metal impurities.

[0052] It can be understood that, preferably, as Figure 1 shown, the metal impurity treatment capacity value Q of the polysilicon production system = the metal impurities in the raw material silicon powder (cold hydrogenation + chlor - alkali) - the metal impurities in (the externally - rotated silicon powder + the slurry silicon powder + the tail gas silicon powder + the reduced silicon powder + the finished product silicon + the maintenance silicon powder + the slag - discharging silicon powder).

[0053] In the present invention, preferably, the mass P of the externally - rotated silicon powder discharged per shift can be determined as the processing capacity of the externally - rotated equipment.

[0054] The second aspect of the present invention provides the application of the slag - discharging method of the polysilicon production process described in the first aspect of the present invention in the field of polysilicon production.

[0055] By adopting the above - mentioned slag - discharging method, the stability of the polysilicon production process and the product performance within a time period can be improved.

[0056] The present invention will be described in detail below through examples.

[0057] Example 1

[0058] This example is used to illustrate the slag - discharging method of the improved Siemens - process polysilicon production process (the raw material is 100% of 521 silicon, purchased from Inner Mongolia Yutengna Photovoltaic Materials Co., Ltd.), and the method includes: performing slag - discharging treatment on the polysilicon production slurry to obtain slurry silicon powder; the slag - discharging amount Y in the slag - discharging treatment is obtained according to the following steps:

[0059] (1) Calculate the metal impurity treatment capacity value Q of the polysilicon production system when T=(t a , t c ): Statistically calculate the average values of A iron, A aluminum, A calcium, B iron, B aluminum, B calcium, C iron, C aluminum, and C calcium from January 2024 to March 2024, and calculate Q iron, Q aluminum, and Q calcium according to the following formula;

[0060] Q iron = q(A iron - B iron - C iron) = 35.70 - 33.64 - 1.82 = 0.25 t / month;

[0061] Q aluminum = q(A aluminum - B aluminum - C aluminum) = 12.90 - 5.72 - 0.10 = 7.08 t / month;

[0062] Q calcium = q(A calcium - B calcium - C calcium) = 4.99 - 3.56 - 0.15 = 1.28 t / month;

[0063] (2) Calculate the total mass B' of metal impurities in the outer-rotating silicon powder and slurry silicon powder when T=(t b , t c ): According to C' iron, C' aluminum, and C' calcium statistically obtained from February 2024 to March 2024, calculate B' iron, B' aluminum, and B' calcium according to the following formula;

[0064] B' iron = A iron - C' iron - Q iron = 35.70 - 13.95 - 0.25 = 31.51 t / month;

[0065] B' aluminum = A aluminum - C' aluminum - Q aluminum = 12.90 - 0.37 - 7.08 = 5.45 t / month;

[0066] B' calcium = A calcium - C' calcium - Q calcium = 4.99 - 0.66 - 1.28 = 3.05 t / month;

[0067] (3) Calculate the amount of metal impurities O in the outer-rotating silicon powder when T=(t b , t c ): The processing capacity of the outer-rotating equipment is 320 t / month, that is, the amount of P is 320 / 3 / 30×1000 = 3556 Kg. Calculate O iron, O aluminum, and O calcium according to the following system of equations;

[0068] O iron = (-1.514×10 -5 ×P 2 ×1000×P + 0.1435×P - 72.120)×3×

[0069] 30 / 1000 = 22.2 t / month;

[0070] O aluminum = (-2.480×10-6 ×P 2 (+0.0165×P - 16.723)×3×30 / 1000 = 0.94 t / month;

[0071] O calcium = (-0.960×10 -6 ×P 2 (+0.0112×P - 4.873)×3×30 / 1000 = 2.06 t / month;

[0072] (4) Calculate M iron, M aluminum, and M calcium in the slag slurry silicon powder when T = (t b , t c ):

[0073] M iron = B' iron - O iron = 31.5 - 22.2 = 9.30 t / month;

[0074] M aluminum = B' aluminum - O aluminum = 5.45 - 0.94 = 4.51 t / month;

[0075] M calcium = B' calcium - O calcium = 3.05 - 2.06 = 0.99 t / month;

[0076] (5) Calculate the mass N of the slag slurry silicon powder when T = (t b , t c ):

[0077] N1 = 5.773M iron + 19.702;

[0078] N2 = 47.105M aluminum - 129.09;

[0079] N3 = 46.109M calcium + 19.086;

[0080]

[0081] (6) Calculate the predicted slag discharge amount Y of the polysilicon production process;

[0082] Y = N / 0.8 = 73.82 / 0.8 = 92.27 t / month;

[0083] According to "Determination of metal impurity content on the surface of polysilicon - Acid leaching - Inductively coupled plasma mass spectrometry (GB / T 24582 - 2023)" and "Determination of matrix metal impurity content in electronic - grade polysilicon - Inductively coupled plasma mass spectrometry (GB / T 37049 - 2018)", test the performance of the polysilicon products prepared during the slag discharge method described in Example 1. The results show that the proportion of electronic - grade polysilicon material is more than 99%, and among them, the proportion of electronic grade 2 is more than 75%.

[0084] Example 2

[0085] Using a method similar to that of Example 1, except that the throughput of the external rotation device is adjusted downward to 280 t / month, that is, the amount of P is 280 / 3 / 30×1000 = 3111 Kg;

[0086] (1) Q iron = 0.25 t / month; Q aluminum = 7.08 t / month; Q calcium = 1.28 t / month;

[0087] (2) B' iron = 31.51 t / month; B' aluminum = 5.45 t / month; B' calcium = 3.05 t / month;

[0088] (3) O iron = 20.50 t / month; O aluminum = 0.95 t / month; O calcium = 1.86 t / month;

[0089] (4) M iron = 11.01 t / month; M aluminum = 4.50 t / month; M calcium = 1.19 t / month;

[0090] (5) N = 80.01 t / month:

[0091] (6) Y = N / 0.8 = 100.01 t / month;

[0092] According to "Determination of metal impurity content on the surface of polysilicon - Acid leaching - Inductively coupled plasma mass spectrometry method (GB / T 24582 - 2023)" and "Determination of matrix metal impurity content in electronic - grade polysilicon - Inductively coupled plasma mass spectrometry method (GB / T 37049 - 2018)", the performance of the polysilicon products prepared during the slag discharge method described in Example 2 was tested. The results showed that the proportion of electronic - grade polysilicon material was more than 99%, among which the proportion of electronic grade 2 was more than 75%.

[0093] Example 3

[0094] Using a method similar to that of Example 1, except that in the polysilicon production process of the improved Siemens method, 70% of 521 silicon + 30% of 99 silicon (purchased from Inner Mongolia Yutengna Photovoltaic Materials Co., Ltd.) was used to replace 100% of 521 silicon. In the slag discharge method of this process:

[0095] (1) Q iron = 0.25 t / month; Q aluminum = 7.08 t / month; Q calcium = 1.28 t / month;

[0096] (2) B' iron = 35.75 t / month; B' aluminum = 6.47 t / month; B' calcium = 3.39 t / month;

[0097] (3) O iron = 22.20 t / month; O aluminum = 0.94 t / month; O calcium = 2.06 t / month;

[0098] (4) M iron = 13.55 t / month; M aluminum = 5.53 t / month; M calcium = 1.33 t / month;

[0099] (5) N = 103.248 t / month:

[0100] (6) Y = N / 0.8 = 129.06 t / month;

[0101] According to "Determination of metal impurity content on the surface of polysilicon - Acid leaching - Inductively coupled plasma mass spectrometry (GB / T 24582 - 2023)" and "Determination of matrix metal impurity content in electronic - grade polysilicon - Inductively coupled plasma mass spectrometry (GB / T 37049 - 2018)", the performance of the polysilicon products prepared during the slag - discharging method described in Example 3 was tested. The results showed that the proportion of electronic - grade polysilicon materials was more than 99%, among which the proportion of electronic grade 2 was more than 75%.

[0102] Example 4

[0103] A method similar to that of Example 1 was adopted, except that in the polysilicon production process of the improved Siemens method, 70% of 521 silicon + 30% of 99 silicon (purchased from Inner Mongolia Yutengna Photovoltaic Materials Co., Ltd.) was used to replace 100% of 521 silicon; the throughput of the external rotation equipment was increased to 320 t / month, that is, the amount of P was 320 / 3 / 30 × 1000 = 3555 Kg. In the slag - discharging method of this process:

[0104] (1) Q_iron = 0.25 t / month; Q_aluminum = 7.08 t / month; Q_calcium = 1.28 t / month;

[0105] (2) B'_iron = 35.75 t / month; B'_aluminum = 6.47 t / month; B'_calcium = 3.39 t / month;

[0106] (3) O_iron = 22.20 t / month; O_aluminum = 0.94 t / month; O_calcium = 2.06 t / month;

[0107] (4) M_iron = 13.55 t / month; M_aluminum = 5.53 t / month; M_calcium = 1.33 t / month;

[0108] (5) N = 103.248 t / month:

[0109] (6) Y = N / 0.8 = 129.06 t;

[0110] According to "Determination of metal impurity content on the surface of polysilicon - Acid leaching - Inductively coupled plasma mass spectrometry (GB / T 24582 - 2023)" and "Determination of matrix metal impurity content in electronic - grade polysilicon - Inductively coupled plasma mass spectrometry (GB / T 37049 - 2018)", the performance of the polysilicon products prepared during the slag - discharging method described in Example 4 was tested. The results showed that the proportion of electronic - grade polysilicon materials was more than 99%, among which the proportion of electronic grade 2 was more than 75%.

[0111] Comparative Example 1

[0112] The method similar to that of Example 4 was adopted, except that the slag discharge treatment was carried out at a slag discharge amount Y of 1.2 times, that is, the slag discharge amount Y = 129.06×1.2 = 154.87 t / month;

[0113] According to "Determination of metal impurity content on the surface of polysilicon - Acid leaching - Inductively coupled plasma mass spectrometry method (GB / T 24582 - 2023)" and "Determination of matrix metal impurity content in electronic - grade polysilicon - Inductively coupled plasma mass spectrometry method (GB / T 37049 - 2018)", the performance of the polysilicon products prepared during the period of using the slag discharge method described in Comparative Example 1 was tested. The results showed that the proportion of electronic - grade polysilicon materials was more than 99%, and among them, the proportion of electronic grade 2 was more than 77%.

[0114] From the above - mentioned examples and comparative examples, it can be seen that compared with Comparative Example 1, the final product performance has significantly better effects by adopting the slag discharge method of the polysilicon production process described in the present invention. In addition, even if the raw materials change, adopting the slag discharge method described in the present invention can also ensure the stability of the polysilicon production process.

[0115] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and all fall within the protection scope of the present invention.

Claims

1. A slag discharging method for a polysilicon production process, characterized in that, The method includes: discharging the residue in the polysilicon production slurry to obtain slurry silicon powder; the discharge amount Y in the residue discharging treatment is determined according to formula (1); wherein, k is any value in 0.3 - 1.0, a is any value in -1 to 1, and b is any value in -0.1 to 5; Q is the metal impurity treatment capacity value of the polysilicon production system at T=(t a , t c ), and Q = q(A - B - C), where q is any value in the range of 0.7 - 1.3; A is the mass of metal impurities in the raw material silicon powder at T=(t a , t c ), B is the total mass of metal impurities in the outer-rotating silicon powder and the slurry silicon powder at T=(t a , t c ), C is the total mass of metal impurities in the discharged silicon powder other than B at T=(t a , t c ); and the units of A, B, C, and Q are tons; B’ is the total mass of metallic impurities in the externally rotated silicon powder and the slurry silicon powder at T=(t b , t c ). C’ is the total mass of metallic impurities in the externally discharged silicon powder other than B’ at T=(t b , t c ). M is the mass of metallic impurities in the slurry silicon powder at T=(t b , t c ). N is the mass of the slurry silicon powder at T=(t b , t c ). O is the mass of metallic impurities in the externally rotated silicon powder at T=(t b , t c ); and the units of B’, C’, M, N, and O are tons. and, the mass O of metal impurities in the outer-rotating silicon powder is determined according to formula (2); Equation (2): O = c × 10 d P 2 + eP - f; wherein, P is the mass of the externally discharged outer-rotating silicon powder, with the unit of Kg / time; c is any value in -3.0 to 1.0, d is any value in -7 to -4, e is any value in 0.005 - 0.200, and f is any value in 1 - 90.

2. The method according to claim 1, wherein, q is any value in 0.8 - 1.

2.

3. According to the method described in claim 1 or 2, wherein The metal impurities in the silicon powder include iron, aluminum, and calcium.

4. The method according to any one of claims 1 to 3, wherein, Define that when T=(t a , t c ), the processing capacity value of iron in the polysilicon production system is Q_iron, and Q_iron = q(A_iron - B_iron - C_iron); Define that when T=(t a , t c ), the processing capacity value of aluminum in the polysilicon production system is Q_aluminum, and Q_aluminum = q(A_aluminum - B_aluminum - C_aluminum); Define that when T=(t a , t c ), the processing capacity value of calcium in the polysilicon production system is Q calcium, and Q calcium = q(A calcium - B calcium - C calcium); Among them, A iron, A aluminum, and A calcium are the masses of metal impurities iron, aluminum, and calcium in the raw material silicon powder at T = (t a , t c ); B iron, B aluminum, and B calcium are the masses of iron, aluminum, and calcium in the outer-rotating silicon powder and the slurry silicon powder at T = (t a , t c ); C iron, C aluminum, and C calcium are the masses of metal impurities iron, aluminum, and calcium in the outer-discharged silicon powder except B at T = (t a , t c ). The units of A iron, A aluminum, A calcium, B iron, B aluminum, B calcium, C iron, C aluminum, and C calcium are tons.

5. The method according to any one of claims 1-4, wherein, Define that when T=(t b , t c ), the total mass of iron in the externally rotated silicon powder and the slurry silicon powder is B'_iron, and B'_iron = A_iron - C'_iron - Q_iron; Define that when T=(t b , t c ), the total mass of aluminum in the externally rotated silicon powder and the slurry silicon powder is B'aluminum, and B'aluminum = A'aluminum - C'aluminum - Q'aluminum; Define that when T=(t b , t c ), the total mass of calcium in the externally rotated silicon powder and the slurry silicon powder is B' calcium, and B' calcium = A calcium - C' calcium - Q calcium; Among them, C_iron, C_aluminum, and C_calcium are the masses of metallic impurities iron, aluminum, and calcium in the outer discharged silica fume except B' at T = (t b , t c ); the units of B'_iron, B'_aluminum, B'_calcium, C'_iron, C'_aluminum, and C'_calcium are tons.

6. The method according to any one of claims 1-5, wherein Define that when T=(t b , t c ), the masses of iron, aluminum, and calcium in the slag slurry silica powder are M_iron, M_aluminum, and M_calcium respectively; and, M_iron, M_aluminum, and M_calcium are determined by the following formula; (Formula 3-1): M_iron = 0.1732N1 + 3.4085; (Formula 3-2): M_aluminum = 0.0139N2 + 3.4936; (Formula 3-3): M_calcium = 0.0183N3 - 0.0851; Among them, N1, N2, and N3 are all the masses of the slag slurry silica powder at T=(t b , t c ); Preferably, when defining the T=(t b , t c ), the mass of the slag slurry silica powder is calculated according to the following formula:

7. The method according to any one of claims 1-6, wherein Define that when T=(t b , t c ), the masses of iron, aluminum, and calcium in the externally rotated silicon powder are O iron, O aluminum, and O calcium, respectively; and, O iron, O aluminum, and O calcium are determined by the following formula; (Equation 4-1): O iron = -1.514×10 -5 P 2 +0.1435P - 72.120; (Equation 4-2): O aluminum = -2.480×10 -6 P 2 +0.0165P - 16.723; (Equation 4-3): O calcium = -0.960×10 -6 P 2 + 0.0112P - 4.

873.

8. The method according to any one of claims 1-7, wherein, The metal impurities in the raw material silicon powder include: the metal impurities in the raw material silicon powder of the cold hydrogenation process and the metal impurities in the raw material silicon powder of the chlor-alkali process.

9. The method according to any one of claims 1-8, wherein The metal impurities C in the externally discharged silicon powder except B or the metal impurities C' in the externally discharged silicon powder except B' include: the metal impurities in the tail gas silicon powder, the metal impurities in the reduced silicon powder, the metal impurities in the finished silicon, the metal impurities in the overhaul silicon powder, and the metal impurities in the discharged residue silicon powder.

10. Application of the residue discharging method for the polysilicon production process described in any one of claims 1 - 9 in the polysilicon production field.

Images