Method for extracting monatomic silicon powder from organic silicon waste contact

Abstract

The invention provides a method for extracting monatomic silicon powder from organic silicon waste contacts. Accurate grading separation is achieved according to the particle size of particles through dynamic balance of a high-speed rotating centrifugal force field generated by airflow grading equipment and airflow centripetal force; the copper-containing organic silicon waste contact body and the copper-free organic silicon waste contact body can be treated at the same time, various particle size distribution conditions of 400-550 meshes, 500-600 meshes, 600-700 meshes and the like of silicon dioxide can be compatible, core equipment does not need to be replaced, and the equipment transformation cost caused by raw material type changes of enterprises is reduced. Precise separation is achieved by means of the particle size difference of monatomic silicon powder and silicon dioxide. The method adapts to different raw material types (waste contact body recovery silicon) and production scales, is high in separation precision, remarkably improves the resource utilization rate and the economic added value of the organic silicon waste, and is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicone waste resource recycling, and particularly relates to a method for extracting elemental silicon powder from silicone waste contact mass. BACKGROUND

[0002] The contact mass waste produced by the silicone industry mainly includes two types: one is silicone waste contact mass for synthesizing methyl chlorosilane by a direct method (containing 70-80% elemental silicon, 10-15% copper compounds, and having a water content of 14-15% after treatment), and the copper recovery rate is low in the traditional treatment; and the other is waste contact mass containing silica (containing about 45-50% elemental silicon and 50-55% silica, and not containing copper but possibly containing water), and the current existing single screening process cannot accurately separate silicon and silica with different particle sizes.

[0003] Therefore, a method for extracting elemental silicon powder from silicone waste contact mass is urgently needed. SUMMARY

[0004] Therefore, the present application provides a method for extracting elemental silicon powder from silicone waste contact mass, which can realize the step-by-step recovery of silicon and silica, increase the purity of elemental silicon powder from about 50% to 70-90%, adapt to different production scales and purity requirements, and be compatible with different particle size distribution ranges of silica, such as 400-550 mesh, 500-600 mesh, and 600-700 mesh,

[0005] To achieve the above purpose, the present application adopts the following technical scheme:

[0006] The present application provides a method for extracting elemental silicon powder from silicone waste contact mass, which includes the following steps:

[0007] S1, determining the particle size distribution of silica in the silicone waste contact mass;

[0008] S2, according to the particle size distribution of silica, performing three-stage air flow separation on the silicone waste contact mass to obtain silicon powder;

[0009] If the particle size distribution of silica is 500-600 mesh, the three-stage air flow separation specifically includes:

[0010] The silicone waste contact mass is placed in a first air flow classifier, and process parameters are controlled to obtain a product with a particle size of 50-500 mesh; wherein the process parameters controlled by the first air flow classifier are: air flow of 1500-1600 m 3 / h, and rotating speed of 1000-1100 r / min;

[0011] The organosilicon waste catalyst, after separating the 50-500 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 500-600 mesh product was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1100-1200 m³ / h. 3 / h, rotation speed 1800~1900 r / min;

[0012] The organosilicon waste catalyst, after separating the 500-600 mesh product, was placed in a three-stage air classifier. Under controlled process parameters, products with a mesh size of 600 mesh or larger were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 800-1000 m³ / h. 3 / h, rotation speed is 2500~2600r / min.

[0013] Preferably, if the particle size distribution of silica is 400-550 mesh, then the three-stage gas flow separation specifically includes:

[0014] Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate products of 50-400 mesh. The process parameters controlled by the primary air classifier were: airflow rate of 1800-1900 m³ / h. 3 / h, rotation speed 1000~1100r / min;

[0015] The organosilicon waste catalyst, after separating the 50-400 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 400-550 mesh product was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1400-1500 m³ / h. 3 / h, rotation speed is 1500~1600 r / min;

[0016] Organosilicon waste catalyst, from which 400-550 mesh products were separated, was placed in a three-stage air classifier. Under controlled process parameters, products larger than 550 mesh were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 1200-1300 m³ / h. 3 / h, rotation speed is 2300~2400r / min.

[0017] Preferably, if the particle size distribution of silica is 600-700 mesh, then the three-stage gas flow separation specifically includes:

[0018] Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate products of 50-600 mesh. The process parameters controlled by the primary air classifier were: airflow rate of 1900-2000 m³ / h. 3 / h, rotation speed 1000~1100r / min;

[0019] The organosilicon waste catalyst, after separating the 50-600 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 600-700 mesh product was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1200-1300 m³ / h. 3 / h, rotation speed 2000~2100 r / min;

[0020] The organosilicon waste catalyst, from which 600-700 mesh products were separated, was placed in a three-stage air classifier. Under controlled process parameters, products with a mesh size of 700 mesh or larger were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 1000-1100 m³ / h. 3 / h, rotation speed is 2700~2800r / min.

[0021] Preferably, the D97 of the separated product (50-500 mesh) is 297-299 μm;

[0022] The D97 of the product obtained from the separation of 500-600 mesh was 24-25 μm;

[0023] The D97 of the separated products with a mesh size of 600 or larger is 10~11 μm.

[0024] Preferably, the D97 of the separated product with a mesh size of 50-400 is 297-299 μm;

[0025] The D97 of the separated product with a mesh size of 400-550 was 35-36 μm.

[0026] The D97 of the separated products with a mesh size of 550 or larger is 10~11 μm.

[0027] Preferably, the D97 of the product obtained from the separation of 50-600 mesh is 297-299 μm;

[0028] The D97 of the separated product with a mesh size of 600-700 was 20-21 μm;

[0029] The D97 of the separated products with a mesh size of 700 or larger is 8-9 μm.

[0030] Preferably, if the waste silicone catalyst contains copper, the copper in the waste silicone catalyst is recovered before the three-stage airflow separation, and then the copper-recovered waste silicone catalyst is passed through a 50-60 mesh vibrating screen; the copper recovery from the waste silicone catalyst includes the following steps:

[0031] The waste silicone catalyst is soaked in a leachate containing sulfuric acid and hydrogen peroxide, and the pH is adjusted to 1-3. Iron powder is added to replace the copper in the waste silicone catalyst, and the copper obtained by replacement is recovered. The soaking temperature is 80-85℃ and the soaking time is 2-3 hours. The mass fraction of sulfuric acid and hydrogen peroxide in the leachate is 5-10% and 5-10% respectively.

[0032] Preferably, after separating and obtaining a product of 50-500 mesh, the method further includes soaking the product of 50-500 mesh in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder;

[0033] The mass ratio of the 50-500 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%.

[0034] After obtaining a product with a mesh size of 600 or larger, the process further includes soaking the product with a mesh size of 600 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 600 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

[0035] Preferably, after separating the product of 50-400 mesh, the method further includes soaking the product of 50-400 mesh in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder;

[0036] The mass ratio of the 50-400 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%.

[0037] After obtaining a product with a mesh size of 550 or larger, the process further includes soaking the product with a mesh size of 550 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 550 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

[0038] Preferably, after separating and obtaining a product of 50-600 mesh, the process further includes soaking the product of 50-600 mesh in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder.

[0039] The mass ratio of the 50-600 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%.

[0040] After obtaining a product with a mesh size of 700 or larger, the process further includes soaking the product with a mesh size of 700 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 700 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

[0041] The method for extracting elemental silicon powder from waste organosilicon catalysts of the present invention has the following advantages over the prior art:

[0042] This invention discloses a method for extracting elemental silicon powder from waste organosilicon catalysts. Due to the significant difference in particle size distribution between elemental silicon and silica in the waste organosilicon catalysts, this method utilizes this characteristic. It achieves precise separation based on particle size through the dynamic balance between the high-speed rotating centrifugal force field generated by an airflow classifier and the centripetal force of the airflow. It can simultaneously process both copper-containing and copper-free organosilicon catalysts and is compatible with various silica particle size distributions such as 400-550 mesh, 500-600 mesh, and 600-700 mesh, without requiring replacement of core equipment, thus reducing equipment modification costs for enterprises due to changes in raw material type. The separation accuracy is high: the final purity of silicon powder recovered from waste catalysts is ≥70%, and the purity of silicon recovered through upgraded pathways is ≥80%, meeting the needs of different application scenarios. XRD analysis confirms the high purity of the silicon powder. Compositional analysis shows that the silica separation rate is ≥95%, and it can be recycled and reused separately; the resource utilization rate is high: the copper recovery rate is ≥90% (purity ≥70%), the ultrafine material is recycled and reused, and no secondary waste is generated, which meets the requirements of environmental protection and resource recycling; the industrial adaptability is strong: the equipment used (dryer, vibrating screen, air classifier) ​​are all mature industrial equipment, which can be connected with existing organosilicon production lines, and the investment payback period for large-scale production is 1.5~2 years. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the three-stage airflow classification of the present invention;

[0045] Figure 2 This is a particle size distribution diagram of the organosilicon waste catalyst in Example 2;

[0046] Figure 3 This represents the cumulative volume percentage of the organosilicon waste catalyst in Example 1;

[0047] Figure 4The XRD pattern of the silicon-containing powder in step S1 of Example 1;

[0048] Figure 5 The product with a mesh size of 600 or larger in step S5 of Example 1 was soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1.5 hours, filtered, and the XRD pattern of silicon powder was obtained. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0051] This application provides a method for extracting elemental silicon powder from waste organosilicon catalysts. The core of this method lies in first determining the actual particle size distribution range of silica in the waste organosilicon catalysts (e.g., 400-550 mesh, 500-600 mesh, 600-700 mesh, etc.) through sieving combined with XRD and chemical analysis. Based on the silica particle size distribution, the waste organosilicon catalysts are subjected to three-stage airflow separation. The three-stage airflow separation parameters are adjusted accordingly to achieve precise separation and obtain silicon powder. The specific steps include:

[0052] S1. Determine the particle size distribution of silica in the organosilicon waste catalyst;

[0053] S2. Based on the particle size distribution of silica, the organosilicon waste catalyst is subjected to three-stage airflow separation to obtain silicon powder;

[0054] If the particle size distribution of silica is between 500 and 600 mesh, then the three-stage gas flow separation specifically includes:

[0055] Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate products of 50-500 mesh. The process parameters controlled by the primary air classifier were: airflow rate of 1500-1600 m³ / h. 3 / h, rotation speed 1000~1100r / min;

[0056] The organosilicon waste catalyst, after separating the 50-500 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 500-600 mesh product was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1100-1200 m³ / h. 3 / h, rotation speed 1800~1900 r / min;

[0057] The organosilicon waste catalyst, after separating the 500-600 mesh product, was placed in a three-stage air classifier. Under controlled process parameters, products with a mesh size of 600 mesh or larger were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 800-1000 m³ / h. 3 / h, rotation speed is 2500~2600r / min.

[0058] This invention relates to a method for extracting elemental silicon powder from waste organosilicon catalysts. Due to the significant difference in particle size distribution between elemental silicon and silica in the waste organosilicon catalysts, this method utilizes this characteristic. It achieves precise separation based on particle size through the dynamic balance between the high-speed rotating centrifugal force field generated by an airflow classifier and the centripetal force of the airflow. Specifically, for silica with a particle size distribution of 500-600 mesh (i.e., 21.17-25.40 μm), a primary airflow separation is performed, and process parameters are controlled.

[0059] The process involves separating products of 50-500 mesh (i.e., 25.40-296.94μm) (most of which are silicon powder), then separating the remaining material through a two-stage airflow separation process with controlled process parameters to separate products of 500-600 mesh (most of which are silicon dioxide). The remaining material is then separated again through a three-stage airflow separation process with controlled process parameters to separate products of 600 mesh and above (most of which are silicon powder). By adjusting the speed of the classifier wheel and optimizing the airflow parameters, efficient separation of materials of different particle sizes can be achieved, significantly improving the purity of elemental silicon.

[0060] Specifically, refer to Figure 1 As shown, primary separation: The material is fed into the multi-rotor primary air classifier 11 via the vacuum feeder 10, with the classifier wheel speed set to 1000~1100 r / min and the air flow rate to 1500~1600 m³ / min. 3At 10:00 AM, under centrifugal force, 50-500 mesh elemental silicon particles, due to their larger particle size, experience a centrifugal force greater than the centripetal force of the airflow, falling along the cylinder wall and exiting from the primary discharge port as the first-stage product. Secondary separation (500-600 mesh mixture separation): Fine particles that did not settle after primary separation enter the secondary classification zone. The rotation speed of the 12 classifying wheel in the secondary air classifier is adjusted to 1800-1900 r / min, and the airflow rate is 1100-1200 m³ / min. 3 / h, increasing the centrifugal force field intensity, separates the 500-600 mesh elemental silicon and silica mixed particles, which are discharged from the secondary discharge port and can be returned to the pretreatment process for re-crushing and classification, improving resource utilization; Tertiary separation (separation of high-purity elemental silicon above 600 mesh): The fine particles above 600 mesh remaining after the secondary classification enter the tertiary classification zone. The speed of the 13 classifying wheel of the secondary air classifier is set to 2500-2600 r / min, and the air flow rate is 800-1000 m³ / min. 3 / h; High-purity elemental silicon particles, due to their small size, pass through the gaps between the classifying blades with the airflow and are collected in a pulse dust collector as the third-stage product (elemental silicon purity 85%~90%). The dust-laden gas generated during the classification process is filtered and purified by the dust collector before being discharged, meeting environmental protection standards; the three-stage classification products are dried (temperature 60~80℃, time 2~4h) to remove moisture.

[0061] In some embodiments, if the particle size distribution of silica is 400-550 mesh, then the three-stage gas flow separation specifically includes:

[0062] Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate products (mostly silicon) into 50-400 mesh products. The process parameters controlled by the primary air classifier were: air flow rate of 1800-1900 m³ / h. 3 / h, rotation speed 1000~1100r / min;

[0063] The organosilicon waste catalyst, after separating the 50-400 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 400-550 mesh product (mostly silica) was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1400-1500 m³ / h. 3 / h, rotation speed is 1500~1600 r / min;

[0064] The organosilicon waste catalyst, from which 400-550 mesh products were separated, was placed in a three-stage air classifier. Under controlled process parameters, products with a mesh size of 550 mesh or larger (mostly silicon powder) were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 1200-1300 m³ / h. 3 / h, rotation speed is 2300~2400r / min.

[0065] In some embodiments, if the particle size distribution of silica is 600-700 mesh (19.81-21.17 μm), then the three-stage gas flow separation specifically includes:

[0066] Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate them into 50-600 mesh products (mostly silicon). The process parameters controlled by the primary air classifier were: air flow rate of 1900-2000 m³ / h. 3 / h, rotation speed 1000~1100r / min;

[0067] The organosilicon waste catalyst, after separating the 50-600 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 600-700 mesh product (mostly silica) was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1200-1300 m³ / h. 3 / h, rotation speed 2000~2100 r / min;

[0068] The organosilicon waste catalyst, from which 600-700 mesh products were separated, was placed in a three-stage air classifier. Under controlled process parameters, products larger than 700 mesh (mostly silicon) were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 1000-1100 m³ / h. 3 / h, rotation speed is 2700~2800r / min.

[0069] In some embodiments, the D97 of the product obtained from 50 to 500 mesh is 297 to 299 μm;

[0070] The D97 of the product obtained from the separation of 500-600 mesh was 24-25 μm;

[0071] The D97 of the separated products with a mesh size of 600 or larger is 10~11 μm.

[0072] In some embodiments, the D97 of the product obtained by separating 50-400 mesh is 297-299 μm;

[0073] The D97 of the separated product with a mesh size of 400-550 was 35-36 μm.

[0074] The D97 of the separated products with a mesh size of 550 or larger is 10~11 μm.

[0075] In some embodiments, the D97 of the product obtained by separating 50-600 mesh is 297-299 μm;

[0076] The D97 of the separated product with a mesh size of 600-700 was 20-21 μm;

[0077] The D97 of the separated products with a mesh size of 700 or larger is 8-9 μm.

[0078] In some embodiments, if the waste silicone catalyst contains copper, the copper in the waste silicone catalyst is recovered before the three-stage airflow separation, and then the copper-recovered waste silicone catalyst is passed through a 50-60 mesh vibrating screen; the recovery of copper from the waste silicone catalyst includes the following steps:

[0079] The waste silicone catalyst is soaked in a leachate containing sulfuric acid and hydrogen peroxide, and the pH is adjusted to 1-3. Iron powder is added to replace the copper in the waste silicone catalyst, and the copper obtained by replacement is recovered. The soaking temperature is 80-85℃ and the soaking time is 2-3 hours. The mass fraction of sulfuric acid and hydrogen peroxide in the leachate is 5-10% and 5-10% respectively.

[0080] Specifically, for copper-containing organosilicon waste catalysts, copper must first be recovered through an oxidation-reduction method (to avoid copper impurities affecting the purity of silicon powder).

[0081] In some embodiments, after separating and obtaining a product of 50-500 mesh, the method further includes soaking the product of 50-500 mesh in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder;

[0082] The mass ratio of the 50-500 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%.

[0083] After obtaining a product with a mesh size of 600 or larger, the process further includes soaking the product with a mesh size of 600 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 600 or larger to the mixed acid is (1 to 4): 1, the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

[0084] In some embodiments, after separating the product of 50-400 mesh, the product of 50-400 mesh is further soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtered, and silicon powder is obtained.

[0085] The mass ratio of the 50-400 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%.

[0086] After obtaining a product with a mesh size of 550 or larger, the process further includes soaking the product with a mesh size of 550 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 550 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

[0087] In some embodiments, after separating and obtaining a product of 50-600 mesh, the process further includes soaking the product of 50-600 mesh in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder.

[0088] The mass ratio of the 50-600 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%.

[0089] After obtaining a product with a mesh size of 700 or larger, the process further includes soaking the product with a mesh size of 700 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 700 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

[0090] Furthermore, in order to improve the purity of the separated silicon powder, the products with a mesh size of 50-500, 600 mesh or larger, 50-400, 550 mesh or larger, 50-600, and 700 mesh or larger are soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours. The hydrochloric acid-hydrofluoric acid mixed acid can specifically dissolve impurities such as SiO2, Al, and Fe, ensuring the purity of the silicon powder.

[0091] The method for extracting elemental silicon powder from waste organosilicon catalysts of the present invention has the following beneficial effects:

[0092] Wide raw material adaptability: It can process both copper-containing and copper-free organosilicon waste catalysts at the same time, and is compatible with various particle size distributions of silica such as 400-550 mesh, 500-600 mesh, and 600-700 mesh. There is no need to replace the core equipment, reducing the equipment modification costs caused by changes in raw material type.

[0093] High separation accuracy: The final purity of silicon powder recovered from waste catalysts is ≥70%, and the purity of silicon recovered through the upgraded path is ≥80%, meeting the needs of different application scenarios; XRD and component analysis show that the silicon dioxide separation rate is ≥95%, and it can be recycled and reused separately;

[0094] High resource utilization rate: copper recovery rate ≥90% (purity ≥70%), ultrafine materials are recycled and reused, no secondary waste is generated, which meets the requirements of environmental protection and resource recycling;

[0095] Strong industrial adaptability: The equipment used (dryer, vibrating screen, air classifier) ​​are all mature industrial equipment that can be connected to existing organosilicon production lines. The investment payback period for large-scale production is 1.5 to 2 years.

[0096] The following specific embodiments further illustrate the method for extracting elemental silicon powder from organosilicon waste catalysts according to this application. This section further illustrates the content of the present invention in conjunction with specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0097] Example 1 (Silica distributed in 500-600 mesh, containing copper waste catalyst)

[0098] In this embodiment, the particle size distribution of the organosilicon waste contact is as follows: Figure 3 As shown, after testing, the silica in the organosilicon waste catalyst of this embodiment is concentrated in the 500-600 mesh range, the Si is mainly concentrated in the 50-500 mesh range and above 600 mesh, and the organosilicon waste catalyst contains copper; the method for extracting elemental silicon powder from organosilicon waste catalyst provided in this embodiment includes the following steps:

[0099] S1. Waste silicone catalyst from a certain factory (15% moisture content, 65% silicon (total silicon element) and 12% copper) was placed in a leachate containing sulfuric acid and hydrogen peroxide (5% sulfuric acid and 6% hydrogen peroxide by mass) and soaked at 80°C for 2 hours. Sodium hydroxide was added to adjust the pH to 2, and iron powder was added to displace the copper in the waste silicone catalyst. The copper obtained by displacement was recovered (copper recovery rate 92.6%, purity (i.e., mass fraction) 82.3%), resulting in silicon-containing powder (70% silicon element mass fraction and <0.1% copper). After testing, the silicon dioxide in the waste catalyst was concentrated in the 500-600 mesh range.

[0100] S2. Drying treatment: The silicon-containing powder is dried for 3 hours using a belt dryer (120℃, conveyor belt speed 1m / min);

[0101] S3. Coarse particle screening: The dried silicon-containing powder is passed through a 50-mesh vibrating screen to obtain a mixture; the vibration frequency is 20Hz.

[0102] S4. Place the mixture in a primary air classifier, control the process parameters, and separate to obtain a product of 50-500 mesh (elemental silicon content approximately 71.2%, D97 298μm); wherein the process parameters controlled by the primary air classifier are: air flow rate 1500m³ / h. 3 / h, rotation speed is 1000r / min;

[0103] The mixture after separating the 50-500 mesh product was placed in a two-stage air classifier, and the process parameters were controlled to separate a 500-600 mesh product (which is silicon dioxide, with a purity (i.e., mass content) of 90% and a D97 of 24μm). The process parameters controlled by the two-stage air classifier were: air flow rate of 1200 m³ / h. 3 / h, rotation speed is 1800r / min;

[0104] The mixture after separating the 500-600 mesh product was placed in a three-stage air classifier, and the process parameters were controlled to separate the product to obtain a mesh size of 600 or larger (D97 is 10μm). The process parameters controlled by the three-stage air classifier were: air flow rate of 1000 m³ / h. 3 / h, rotation speed is 2500r / min;

[0105] S5. After separating the product to obtain a mesh size of 50-500, soak it in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1.5 hours, filter it, and obtain silicon powder (the purity (i.e., mass content) of the silicon powder reaches 90.2%).

[0106] The mass ratio of the 50-500 mesh product to the mixed acid is 3:1, and the mixed acid contains 3% hydrochloric acid and 1% hydrofluoric acid.

[0107] After separating the product to obtain a mesh size of 600 or higher, it was soaked in a mixed acid solution containing hydrochloric acid and hydrofluoric acid for 1.5 hours, filtered, and silicon powder was obtained (the purity (i.e., mass content) of the silicon powder reached 91.2%).

[0108] The mass ratio of the product with a mesh size of 600 or larger to the mixed acid is 3:1, and the mixed acid contains 3% hydrochloric acid and 1% hydrofluoric acid.

[0109] Example 2 (Silica distributed in 400-550 mesh, no copper waste catalyst)

[0110] This embodiment provides a method for extracting elemental silicon powder from waste organosilicon catalysts, including the following steps:

[0111] S1. Waste silicone from a certain factory (13% moisture content, 62% total silicon content, no copper), tested and found that the silica is concentrated in the 400-550 mesh range, and the elemental silicon is distributed in the 50-1000 mesh range. Its particle size distribution is as follows: Figure 2 As shown), dry at 105℃ for 2.5h;

[0112] S2. Coarse particle screening: The dried silicon-containing powder is passed through a 60-mesh vibrating screen to obtain a mixture; the vibration frequency is 25Hz.

[0113] S3. Place the mixture in a primary air classifier, control the process parameters, and separate to obtain a product with a mesh size of 50-400 (elemental silicon content approximately 72.6%, D97 298μm); wherein the process parameters controlled by the primary air classifier are: air flow rate of 1800 m³ / h. 3 / h, rotation speed is 1050r / min;

[0114] The mixture after separating the 50-400 mesh product was placed in a two-stage air classifier, and the process parameters were controlled to separate a 400-550 mesh product (mostly silica, purity 91%, D97 35μm); the process parameters controlled by the two-stage air classifier were: air flow rate 1500 m³ / h. 3 / h, rotation speed of 1600r / min (suitable for particle size separation of 400~550 mesh);

[0115] The mixture after separating the 400-550 mesh product was placed in a three-stage air classifier, and the process parameters were controlled to separate the product to obtain a mesh size of 550 or larger (D97 is 10μm). The process parameters controlled by the three-stage air classifier were: air flow rate of 1200 m³ / h. 3 / h, rotation speed is 2300r / min;

[0116] S4. After separating the product to obtain 50-400 mesh, soak it in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1.8 hours, filter it, and obtain silicon powder (silicon powder purity reaches 88.5%).

[0117] The mass ratio of the 50-400 mesh product to the mixed acid is 2:1, and the mass fraction of hydrochloric acid in the mixed acid is 5%, while the mass fraction of hydrofluoric acid is 3%.

[0118] After separating the product to obtain a particle size of 550 mesh or higher, it was soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1.8 hours, filtered, and silicon powder was obtained (the purity of silicon powder reached 89.8%).

[0119] The mass ratio of the product with a mesh size of 550 or larger to the mixed acid is 2:1. The mass fraction of hydrochloric acid in the mixed acid is 5%, and the mass fraction of hydrofluoric acid is 3%.

[0120] Example 3 (Silica distributed at 600-700 mesh, no copper waste catalyst)

[0121] This embodiment provides a method for extracting elemental silicon powder from waste organosilicon catalysts, including the following steps:

[0122] S1. A certain factory's waste silicone catalyst (moisture content 11%, total silicon content 58%, no copper, and after testing, the silica is concentrated in the 600~700 mesh and the elemental silicon is distributed in the 50~1000 mesh) was dried at 110℃ for 2 hours;

[0123] S2. Coarse particle screening: The dried silicon-containing powder is passed through a 55-mesh vibrating screen to obtain a mixture; the vibration frequency is 28Hz.

[0124] S3. Place the mixture in a primary air classifier, control the process parameters, and separate to obtain a product of 50-600 mesh (elemental silicon content approximately 71.8%, D97 298μm); wherein the process parameters controlled by the primary air classifier are: air flow rate 1900 m³ / h. 3 / h, rotation speed is 1080r / min;

[0125] The mixture after separating the 50-600 mesh product was placed in a two-stage air classifier. Under controlled process parameters, a 600-700 mesh product was obtained (mostly silica, with a purity of 90.5% and a D97 of 20.5 μm). The process parameters controlled by the two-stage air classifier were: air flow rate of 1300 m³ / h. 3 / h, rotation speed of 2000r / min (suitable for 600~700 mesh particle size separation requirements);

[0126] The mixture after separating the 600-700 mesh product was placed in a three-stage air classifier, and the process parameters were controlled to separate the product to obtain a mesh size of 700 or larger (D97 is 8μm). The process parameters controlled by the three-stage air classifier were: air flow rate of 1100 m³ / h. 3 / h, rotation speed is 2700r / min;

[0127] S4. After separating the product to obtain a 50-600 mesh size, soak it in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1.2 hours, filter it, and obtain silicon powder (silicon powder purity reaches 87.3%).

[0128] The mass ratio of the 50-600 mesh product to the mixed acid is 4:1, and the mixed acid contains 4% hydrochloric acid and 2% hydrofluoric acid.

[0129] After separating the product to obtain a particle size of 700 mesh or higher, it was soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1.2 hours, filtered, and silicon powder was obtained (the purity of silicon powder reached 88.6%).

[0130] The mass ratio of the product with a mesh size of 700 or larger to the mixed acid is 4:1. The mass fraction of hydrochloric acid in the mixed acid is 4%, and the mass fraction of hydrofluoric acid is 2%.

[0131] Example 4 (Silica distributed in 400-550 mesh, containing copper waste catalyst)

[0132] This embodiment provides a method for extracting elemental silicon powder from waste organosilicon catalysts, including the following steps:

[0133] S1. Waste silicone catalyst from a certain factory (moisture content 14%, Fe 1.0%, Al 0.7%, copper 10%, total silicon content 63%, silica concentrated in 400-550 mesh, elemental silicon in 50-1000 mesh) was placed in a leachate containing sulfuric acid and hydrogen peroxide (sulfuric acid mass fraction 8%, hydrogen peroxide mass fraction 8%) and soaked at 83℃ for 2.5h. Sodium hydroxide was added to adjust the pH to 2.5, and iron powder was added to displace the copper in the waste silicone catalyst. The copper obtained from the displacement was recovered (copper recovery rate 96.1%, purity (i.e. mass fraction) 86.8%), resulting in silicon-containing powder (silicon mass fraction 68%, copper <0.1%).

[0134] S2. Drying treatment: The silicon-containing powder was dried for 3.2 hours using a belt dryer (125℃, conveyor belt speed 0.9m / min);

[0135] S3. Coarse particle screening: The dried silicon-containing powder is passed through a 50-mesh vibrating screen to obtain a mixture; the vibration frequency is 22Hz.

[0136] S4. Place the mixture in a primary air classifier, control the process parameters, and separate to obtain a product with a mesh size of 50-400 mesh (70.5% elemental silicon content, D97 of 298 μm); wherein the process parameters controlled by the primary air classifier are: air flow rate of 1700 m³ / h. 3 / h, rotation speed is 1060r / min;

[0137] The mixture after separating the 50-400 mesh product was placed in a two-stage air classifier. Under controlled process parameters, a 400-550 mesh product (mostly silica, 90% purity, D97 35μm) was obtained. The controlled process parameters for the two-stage air classifier were: air flow rate of 1400 m³ / h. 3 / h, rotation speed is 1550r / min;

[0138] The mixture after separating the 400-550 mesh product was placed in a three-stage air classifier, and the process parameters were controlled to separate the product to obtain a mesh size of 550 or larger (D97 is 10μm). The process parameters controlled by the three-stage air classifier were: air flow rate of 1250 m³ / h. 3 / h, rotation speed is 2350r / min;

[0139] S5. After separating the product to obtain 50-400 mesh, soak it in a mixed acid containing hydrochloric acid and hydrofluoric acid for 2 hours, filter it, and obtain silicon powder (silicon powder purity reaches 86.7%).

[0140] The mass ratio of the 50-400 mesh product to the mixed acid is 3:1, and the mixed acid contains 3% hydrochloric acid and 1% hydrofluoric acid.

[0141] After separating the product with a mesh size of 550 or higher, it was soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 2 hours, filtered, and silicon powder was obtained (the purity of silicon powder reached 89.1%).

[0142] The mass ratio of the product with a mesh size of 550 or larger to the mixed acid is 3:1, and the mixed acid contains 3% hydrochloric acid and 1% hydrofluoric acid.

[0143] Example 5 (Silica distributed in 600-700 mesh, copper-containing waste catalyst)

[0144] This embodiment provides a method for extracting elemental silicon powder from waste organosilicon catalysts, including the following steps:

[0145] S1. Waste silicone catalyst from a certain factory (moisture content 15%, Fe 1.3%, Al 0.9%, copper 11%, total silicon content 61%, silica concentrated in 600-700 mesh, elemental silicon in 50-1000 mesh) was placed in a leachate containing sulfuric acid and hydrogen peroxide (sulfuric acid mass fraction 10%, hydrogen peroxide mass fraction 10%) and soaked at 85℃ for 3 hours. Sodium hydroxide was added to adjust the pH to 3, and iron powder was added to replace the copper in the waste silicone catalyst (copper recovery rate 93.2%, purity (i.e., mass fraction) 87.3%). The copper obtained from the replacement was recovered to obtain silicon-containing powder (silicon mass fraction 66%, copper <0.1%).

[0146] S2. Drying treatment: The silicon-containing powder was dried for 3.5 hours using a belt dryer (130℃, conveyor belt speed 0.8m / min);

[0147] S3. Coarse particle screening: The dried silicon-containing powder is passed through a 50-mesh vibrating screen to obtain a mixture; the vibration frequency is 24Hz.

[0148] S4. Place the mixture in a primary air classifier, control the process parameters, and separate to obtain a product of 50-600 mesh (elemental silicon content approximately 70.8%, D97 298μm); wherein the process parameters controlled by the primary air classifier are: air flow rate 2000 m³ / h. 3 / h, rotation speed is 1100r / min;

[0149] The mixture after separating the 50-600 mesh product was placed in a two-stage air classifier. Under controlled process parameters, a 600-700 mesh product (mostly silica, 91% purity, D97 20.5μm) was obtained. The controlled process parameters for the two-stage air classifier were: air flow rate of 1200 m³ / h. 3 / h, rotation speed is 2050r / min;

[0150] The mixture after separating the 600-700 mesh product was placed in a three-stage air classifier, and the process parameters were controlled to separate the product to obtain a mesh size of 700 mesh or larger (D97 is 8μm). The process parameters controlled by the three-stage air classifier were: air flow rate of 1000 m³ / h. 3 / h, rotation speed is 2800r / min;

[0151] S5. After separating the product to obtain a 50-600 mesh size, soak it in a mixed acid containing hydrochloric acid and hydrofluoric acid for 2.2 hours, filter it, and obtain silicon powder (silicon powder purity reaches 85.9%).

[0152] The mass ratio of the 50-600 mesh product to the mixed acid is 3:1, and the mass fraction of hydrochloric acid in the mixed acid is 3% and the mass fraction of hydrofluoric acid is 1%.

[0153] After separating the product to obtain a particle size of 700 mesh or higher, it was soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 2.2 hours, filtered, and silicon powder was obtained (the purity of silicon powder reached 87.8%).

[0154] The mass ratio of the product with a mesh size of 700 or larger to the mixed acid is 3:1. The mass fraction of hydrochloric acid in the mixed acid is 3%, and the mass fraction of hydrofluoric acid is 1%.

[0155] Comparative Example 1

[0156] This comparative example provides a method for extracting elemental silicon powder from waste organosilicon catalysts, including the following steps:

[0157] S1. Waste silicone catalyst from a certain factory (moisture content 14%, Fe 1.0%, Al 0.7%, copper 10%, total silicon content 63%, with silica concentrated in 400-550 mesh and elemental silicon in 50-1000 mesh) was placed in a leachate containing sulfuric acid and hydrogen peroxide (sulfuric acid mass fraction 8%, hydrogen peroxide mass fraction 8%) and soaked at 83℃ for 2.5 hours. Sodium hydroxide was added to adjust the pH to 2.5, and iron powder was added to displace the copper in the waste silicone catalyst. The displaced copper was recovered to obtain silicon-containing powder (silicon mass fraction 68%, copper <0.1%).

[0158] S2. Drying treatment: The silicon-containing powder was dried for 3.2 hours using a belt dryer (125℃, conveyor belt speed 0.9m / min);

[0159] S3. Coarse particle screening: The dried silicon-containing powder is passed through a 50-mesh vibrating screen to obtain a mixture; the vibration frequency is 22Hz.

[0160] S4. Place the mixture in a primary air classifier, control the process parameters to ensure a uniform gap between the classifier wheel and the equipment cylinder (≤0.5mm), an initial rotation speed of 2000 r / min, and an air flow rate of 1750 m³ / min. 3 / h; fine particles of 500 mesh or larger are obtained, and coarse particles (50~500 mesh) account for 24%, of which elemental silicon accounts for 70.5%; fine particles account for 76%, of which elemental silicon accounts for 55~60%, and the remainder is silicon dioxide. The separation accuracy is far lower than that of the three-stage adaptive airflow classification process of the present invention. Figure 4 The image shows the XRD pattern of the silicon-containing powder in step S1 of Example 1. It can be seen from the image that the silicon powder before separation contains Si and SiO2 phases. Figure 5 In Example 1, the product with a mesh size of 600 or larger was soaked in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1.5 hours, filtered, and the XRD pattern of silicon powder was obtained. It can be seen from the figure that the silicon powder phase is Si and there is no SiO2, thus achieving the separation of Si and SiO2.

[0161] The above description is only a preferred embodiment of the present invention and is 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 extracting elemental silicon powder from organosilicon waste catalyst, characterized in that, Includes the following steps: S1. Determine the particle size distribution of silica in the organosilicon waste catalyst; S2. Based on the particle size distribution of silica, the waste organosilicon catalyst is subjected to three-stage airflow separation to obtain silicon powder; If the particle size distribution of silica is between 500 and 600 mesh, then the three-stage gas flow separation specifically includes: Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate products of 50-500 mesh. The process parameters controlled by the primary air classifier were: airflow rate of 1500-1600 m³ / h. 3 / h, rotation speed 1000~1100r / min; The organosilicon waste catalyst, after separating the 50-500 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 500-600 mesh product was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1100-1200 m³ / h. 3 / h, rotation speed 1800~1900 r / min; The organosilicon waste catalyst, after separating the 500-600 mesh product, was placed in a three-stage air classifier. Under controlled process parameters, products with a mesh size of 600 mesh or larger were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 800-1000 m³ / h. 3 / h, rotation speed is 2500~2600r / min.

2. The method for extracting elemental silicon powder from organosilicon waste as described in claim 1, characterized in that, If the particle size distribution of silica is between 400 and 550 mesh, then the three-stage gas flow separation specifically includes: Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate products of 50-400 mesh. The process parameters controlled by the primary air classifier were: airflow rate of 1800-1900 m³ / h. 3 / h, rotation speed 1000~1100r / min; The organosilicon waste catalyst, after separating the 50-400 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 400-550 mesh product was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1400-1500 m³ / h. 3 / h, rotation speed is 1500~1600 r / min; Organosilicon waste catalyst, from which 400-550 mesh products were separated, was placed in a three-stage air classifier. Under controlled process parameters, products larger than 550 mesh were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 1200-1300 m³ / h. 3 / h, rotation speed is 2300~2400r / min.

3. The method for extracting elemental silicon powder from organosilicon waste as described in claim 1, characterized in that, If the particle size distribution of silica is 600-700 mesh, then the three-stage gas flow separation specifically includes: Waste organosilicon catalysts were placed in a primary air classifier, and the process parameters were controlled to separate products of 50-600 mesh. The process parameters controlled by the primary air classifier were: airflow rate of 1900-2000 m³ / h. 3 / h, rotation speed 1000~1100r / min; The organosilicon waste catalyst, after separating the 50-600 mesh product, was placed in a two-stage air classifier. Under controlled process parameters, a 600-700 mesh product was obtained. The controlled process parameters for the two-stage air classifier were: airflow rate of 1200-1300 m³ / h. 3 / h, rotation speed 2000~2100 r / min; The organosilicon waste catalyst, from which 600-700 mesh products were separated, was placed in a three-stage air classifier. Under controlled process parameters, products with a mesh size of 700 mesh or larger were obtained. The controlled process parameters for the three-stage air classifier were: airflow rate of 1000-1100 m³ / h. 3 / h, rotation speed is 2700~2800r / min.

4. The method for extracting elemental silicon powder from organosilicon waste as described in claim 1, characterized in that, The D97 of the separated products with a mesh size of 50-500 was 297-299 μm; The D97 of the product obtained from the separation of 500-600 mesh was 24-25 μm; The D97 of the separated products with a mesh size of 600 or larger is 10~11 μm.

5. The method for extracting elemental silicon powder from organosilicon waste as described in claim 2, characterized in that, The D97 of the separated products with a mesh size of 50-400 was 297-299 μm; The D97 of the separated product with a mesh size of 400-550 was 35-36 μm. The D97 of the separated products with a mesh size of 550 or larger is 10~11 μm.

6. The method for extracting elemental silicon powder from organosilicon waste as described in claim 3, characterized in that, The D97 of the separated products with a mesh size of 50-600 was 297-299 μm; The D97 of the separated product with a mesh size of 600-700 was 20-21 μm; The D97 of the separated products with a mesh size of 700 or larger is 8-9 μm.

7. The method for extracting elemental silicon powder from organosilicon waste as described in claim 1, characterized in that, If the waste silicone catalyst contains copper, the copper should be recovered from the waste silicone catalyst before the three-stage airflow separation. Then, the copper-recovered waste silicone catalyst should be passed through a 50-60 mesh vibrating screen. The copper recovery process includes the following steps: After soaking the waste organosilicon catalyst in a leachate containing sulfuric acid and hydrogen peroxide, the pH is adjusted to 1-3. Iron powder is added to displace the copper in the waste organosilicon catalyst, and the displaced copper is recovered. The soaking temperature is 80-85℃ and the soaking time is 2-3 hours. The mass fraction of sulfuric acid and hydrogen peroxide in the leachate is 5-10% and 5-10% respectively.

8. The method for extracting elemental silicon powder from organosilicon waste as described in claim 1, characterized in that, After separating and obtaining a product of 50-500 mesh, the process also includes soaking the product of 50-500 mesh in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder. The mass ratio of the 50-500 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%. After obtaining a product with a mesh size of 600 or larger, the process further includes soaking the product with a mesh size of 600 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 600 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

9. The method for extracting elemental silicon powder from organosilicon waste as described in claim 2, characterized in that, After separating the 50-400 mesh product, the process also includes soaking the 50-400 mesh product in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder. The mass ratio of the 50-400 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%. After obtaining a product with a mesh size of 550 or larger, the process further includes soaking the product with a mesh size of 550 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 550 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

10. The method for extracting elemental silicon powder from organosilicon waste catalyst as described in claim 3, characterized in that, After separating and obtaining a product of 50-600 mesh, the process also includes soaking the 50-600 mesh product in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1-3 hours, filtering, and obtaining silicon powder. The mass ratio of the 50-600 mesh product to the mixed acid is (1-4):1, and the mass fraction of hydrochloric acid in the mixed acid is 2-8%, and the mass fraction of hydrofluoric acid is 1-5%. After obtaining a product with a mesh size of 700 or larger, the process further includes soaking the product with a mesh size of 700 or larger in a mixed acid containing hydrochloric acid and hydrofluoric acid for 1 to 3 hours, filtering, and obtaining silicon powder; wherein the mass ratio of the product with a mesh size of 700 or larger to the mixed acid is (1 to 4): 1, and the mass fraction of hydrochloric acid in the mixed acid is 2 to 8%, and the mass fraction of hydrofluoric acid is 1 to 5%.

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