Production method of active silica powder

Abstract

The invention discloses a production method of active silica powder. The production method comprises the following steps: S1, selecting natural quartz ore or fused quartz as a raw material and carrying out pretreatment; s2, carrying out crushing and grinding treatment on the pretreated silica powder raw material; s3, impurities in the ground silica powder are removed; s4, carrying out activating treatment on the silicon micro powder from which the impurities are removed; s5, screening and grading the activated silica powder; s6, carrying out deionizing treatment on the silica powder subjected to particle size division; the preparation process is low in requirement and cost and can be widely popularized, and the active silica powder which is high in quality, high in performance and easy to mix can be prepared through the production method, so that the application requirements in different fields are met; the prepared active silica powder product has the advantages of excellent dielectric property, low thermal neck expansion coefficient, high heat conductivity coefficient, good suspension property, stable physical and chemical properties, unique optical properties and the like, and is widely applied to the fields of electronics, communication, aerospace, chemical industry and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon micropowder production methods, in particular to a method for producing active silicon micropowder. Background Art

[0002] Silica micropowder is a non-toxic, odorless and pollution-free inorganic non-metallic material. The raw materials are natural quartz or fused quartz. The preparation methods of silica micropowder mainly include physical method, chemical method and physical-chemical method. Among them, the physical preparation methods mainly include flame spheroidization method, high-temperature melt spraying method, plasma method, high-temperature calcination spheroidization, etc.; the chemical preparation methods mainly include gas phase method, hydrothermal synthesis method, self-propagating low-temperature combustion method, sol-gel method, precipitation method and microemulsion method, etc.; currently in the market, there are three main technical paths for spherical silica micropowder that can meet mass production conditions, namely flame melting spherical silica micropowder, direct combustion / VMC method spherical silica micropowder and chemical synthesis spherical silica micropowder.

[0003] The above-mentioned methods for preparing silicon micropowder all have high requirements and high preparation costs. Therefore, the present invention proposes a production method for active silicon micropowder that can be more widely promoted, with low preparation process requirements and low cost. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art mentioned in the background technology and to propose a method for producing active silicon micropowder.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A method for producing active silicon micropowder comprises the following steps: S1. Select natural quartz ore or fused quartz as raw material and pre-treat it; S11. The silicon dioxide content should reach 99.7% to 99.9% to ensure the purity and activity of the product; S12. Clean the raw materials to remove dirt and impurities on the surface to ensure the purity of the raw materials.

[0006] S2, crushing and grinding the pre-treated silicon micropowder raw materials; S21. Crushing the raw materials through a crusher to obtain smaller particles of quartz. The crushing process should follow the principle of multiple crushing to reduce the particle size of the raw ore as much as possible to facilitate the subsequent grinding process; S22, feeding the crushed quartz particles into a ball mill or a vibration mill for grinding, and obtaining silicon micropowder of a desired particle size by adjusting the mill speed, grinding time and grinding ball ratio; S3, removing impurities from the ground silicon powder; S31, removing iron impurities from the silicon powder by magnetic separation; S32. Using flotation to remove non-ferrous impurities from the silicon powder. During the flotation process, the impurity removal effect is ensured by adjusting parameters such as the dosage of reagents, bubble size, and the speed of the flotation machine; S33, pickling the silicon powder after flotation to further remove metal impurities. During the pickling process, the concentration, temperature and reaction time of the acid solution need to be controlled to ensure the purification effect; S4, activating the silicon micropowder from which impurities have been removed; S41, mixing the silicon micropowder and the activator uniformly, wherein the activator is a mixture of a silane coupling agent and ammonia water; S42, after uniform mixing, reacting at a certain temperature for a constant time, so that the activator reacts with the hydroxyl groups on the surface of the silicon micropowder to form active chemical bonds, thereby increasing the activity of the silicon micropowder; S5. Screening and grading the activated silicon micropowder; S51, using an air classifier or a hydrocyclone to classify the activated silicon micropowder, and obtaining products of different particle size grades by adjusting parameters such as the classifier's rotation speed, air volume, and the structure of the classifying wheel; S52. Screen the graded product to remove oversized or undersized particles to ensure uniform particle size distribution of the product. S6. Deionizing the sized silicon powder; S61, washing the sieved silicon micropowder with deionized water to remove residual activator and impurity ions; S62. The washed silicon micropowder is sent to a dryer for drying. During the drying process, the temperature, humidity and drying time of the dryer need to be controlled to ensure that the moisture content of the silicon micropowder meets the requirements.

[0007] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a production method for active silicon micropowder that can be more widely promoted, with low preparation process requirements and cost. Through this production method, high-quality, high-performance, and easily mixed active silicon micropowder can be prepared to meet application requirements in different fields; The prepared active silicon micropowder products have the advantages of excellent dielectric properties, low thermal expansion coefficient, high thermal conductivity, good suspension performance, stable physical and chemical properties, and unique optical properties. They are widely used in electronics, communications, aerospace, chemical industry and other fields. DETAILED DESCRIPTION

[0008] The present invention may be more readily understood by referring to the following detailed description of preferred embodiments of the present invention and the included Examples. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention pertains. In the event of a conflict, the definitions in this specification shall prevail.

[0009] As used herein, the term "prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0010] The conjunction "consisting of" excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim, rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0011] When amount, concentration or other value or parameter is represented with range, preferred range or the range that a series of upper preferred value and lower preferred value limit are expressed, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, no matter whether this range is disclosed separately.For example, when disclosing scope "1 to 5", described scope should be interpreted as including scope "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc.When numerical range is described in this article, unless otherwise stated, otherwise this scope is intended to include its end value and all integers and fractions within this range.

[0012] The singular includes plural references unless the context clearly dictates otherwise. "Optional" or "either" means that the subsequently described event or incident can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0013] Approximating terms in the specification and claims are used to modify a quantity to indicate that the invention is not limited to that specific quantity and includes acceptable modifications close to that quantity that do not result in a change in the relevant basic function. Accordingly, the use of "about," "approximately," or the like to modify a numerical value indicates that the invention is not limited to that exact numerical value. In some instances, approximating terms may correspond to the precision of the instrument used to measure the value. In the specification and claims of this application, range definitions may be combined and / or interchanged, and unless otherwise indicated, such ranges include all subranges contained therein.

[0014] In addition, the indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e., the number of times the elements or components appear). Therefore, "a" or "an" should be interpreted as including one or at least one, and elements or components in the singular also include plural forms, unless the number is obviously intended to be singular.

[0015] The technical solutions in 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 part of the embodiments of the present invention, rather than all the embodiments.

[0016] A method for producing active silicon micropowder comprises the following steps: S1. Select natural quartz ore or fused quartz as raw material and pre-treat it. The silicon dioxide content in the selected raw material should reach 99.7% to 99.9% to ensure the purity and activity of the product. Then clean the raw material to remove surface dirt and impurities to ensure the purity of the raw material.

[0017] S2, crushing and grinding the pre-treated silicon micropowder raw materials, specifically, crushing the raw materials through a crusher to obtain smaller particles of quartz. It should be noted that the crushing process should follow the principle of multiple crushing to reduce the particle size of the original ore as much as possible to facilitate the subsequent grinding process. The crushed quartz particles are then sent to a ball mill or a vibration mill for grinding. During the grinding process, the speed of the mill, the grinding time and the ratio of the grinding balls are adjusted to obtain silicon micropowder of the desired particle size; S3. Remove impurities from the ground silicon micropowder. First, remove the iron impurities in the silicon micropowder by magnetic separation. Then, remove the non-ferrous impurity minerals in the silicon micropowder by flotation. During the flotation process, adjust the parameters such as the dosage of the reagent, the bubble size, and the speed of the flotation machine to ensure the removal effect of impurities. Then, the silicon micropowder after flotation is pickled to further remove metal impurities. During the pickling process, the concentration, temperature, and reaction time of the acid solution need to be controlled to ensure the purification effect. S4. Activate the silicon micropowder after removing impurities. First, mix the silicon micropowder and the activator evenly. The activator can be a mixture of a silane coupling agent and ammonia water in a mixing ratio of 1:1. The ammonia content in the ammonia water is about 26%. Then, react the mixed silicon micropowder and the activator mixture at a certain temperature for a constant time, for example, 70°C-100°C, so that the activator reacts with the hydroxyl groups on the surface of the silicon micropowder to form active chemical bonds, thereby increasing the activity of the silicon micropowder and improving its mixing performance with other materials. S5. Screening and grading the activated silicon micropowder: first, using an air classifier or a hydrocyclone to classify the activated silicon micropowder, wherein by adjusting parameters such as the speed, air volume, and structure of the classifying wheel of the classifier, products of different particle sizes are obtained, and then the classified products are screened to remove oversized or undersized particles to ensure uniform particle size distribution of the product; S6. Deionize the sized silicon micropowder, specifically, wash the sieved silicon micropowder with deionized water to remove residual activator and impurity ions. After the deionization treatment is completed, the silicon micropowder is sent to a dryer for drying. During the drying process, the temperature, humidity and drying time of the dryer need to be controlled to ensure that the moisture content of the silicon micropowder meets the requirements; S7. If necessary, the dried silicon micropowder can be subjected to surface modification treatment to further improve its mixing performance and dispersibility with other materials; S8. Package the dried silicon micropowder for easy storage and transportation. Use vacuum packaging or inert gas protection packaging. Ensure the sealing and moisture-proof properties of the packaging to prevent the silicon micropowder from getting damp or contaminated during storage and transportation. Store it in a dry, cool, well-ventilated warehouse, away from direct sunlight and high temperature environment.

[0018] Through the above production method, high-quality, high-performance, and easily miscible active silicon micropowder can be prepared to meet the application needs of different fields. This product has the advantages of excellent dielectric properties, low thermal expansion coefficient, high thermal conductivity, good suspension performance, stable physical and chemical properties, and unique optical properties. It is widely used in electronics, communications, aerospace, chemical industry and other fields.

[0019] Regarding the production method in the above process, it is also necessary to note that: During the production process, various process parameters such as grinding time, temperature, pH value, etc. should be strictly controlled to ensure the quality and performance of the product; The purity, chemical composition and particle size of raw materials need to be tested to ensure that the quality of raw materials meets the requirements; During the production process, key processes such as crushing, grinding, purification, grading and drying are strictly controlled to ensure product quality and performance; The particle size, purity, whiteness and activity of the finished silicon micropowder are tested to ensure that the product meets the relevant standards and customer requirements.

[0020] The examples referred to herein are merely illustrative and serve to illustrate some features of the method of the present invention, and the appended claims are intended to claim the widest possible scope that can be imagined, and the embodiments presented herein are merely illustrative of selected implementation methods according to the combination of all possible embodiments. Therefore, it is the applicant's intention that the appended claims are not limited by the selection of examples illustrating the features of the present invention. Some numerical ranges used in the claims also include subranges therein, and changes in these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A method for producing active silicon micropowder, characterized in that: The following steps are involved: S1. Select natural quartz ore or fused quartz as raw material and pre-treat it; S2, crushing and grinding the pre-treated silicon micropowder raw materials; S3, removing impurities from the ground silicon powder; S4, activating the silicon micropowder from which impurities have been removed; S5. Screening and grading the activated silicon micropowder; S6. Deionize the silicon micropowder after particle size classification.

2. The method for producing active silicon micropowder according to claim 1, wherein: In S1, S11, the silica content should reach 99.7% to 99.9% to ensure the purity and activity of the product; S12. Clean the raw materials to remove dirt and impurities on the surface to ensure the purity of the raw materials.

3. The method for producing active silicon micropowder according to claim 1, wherein: In S2, S21, crushing the raw materials through a crusher to obtain smaller particles of quartz; S22. The crushed quartz particles are sent to a ball mill or a vibration mill for grinding.

4. The method for producing active silicon micropowder according to claim 1, wherein: In S3, S31, the iron impurities in the silicon powder are removed by magnetic separation; S32, removing non-ferrous impurity minerals from the silicon powder by flotation; S33, performing pickling treatment on the silicon micropowder after flotation to further remove metal impurities.

5. The method for producing active silicon micropowder according to claim 1, wherein: In S4, S41, the silicon micropowder is uniformly mixed with an activator, wherein the activator is a mixture of a silane coupling agent and ammonia water; S42. After uniform mixing, the mixture is reacted at a certain temperature for a constant time, so that the activator reacts with the hydroxyl groups on the surface of the silicon micropowder to form active chemical bonds, thereby increasing the activity of the silicon micropowder.

6. The method for producing active silicon micropowder according to claim 1, wherein: The mixing ratio of S411, silane coupling agent and ammonia water is 1:1, and the ammonia content in the ammonia water is about 26%; S42, temperature 70℃-100℃.

7. The method for producing active silicon micropowder according to claim 1, characterized in that: In S5, S51, an air flow classifier or a hydrocyclone is used to classify the activated silicon micropowder; S52. Screen the graded products to remove oversized or undersized particles to ensure uniform particle size distribution of the products.

8. The method for producing active silicon micropowder according to claim 1, wherein: In S6, S61, the sieved silicon micropowder is washed with deionized water to remove residual activator and impurity ions; S62, sending the washed silicon micropowder into a dryer for drying.