CN109553109B - Method for preparing silica sol and silica sol - Google Patents
Method for preparing silica sol and silica sol Download PDFInfo
- Publication number
- CN109553109B CN109553109B CN201710888891.2A CN201710888891A CN109553109B CN 109553109 B CN109553109 B CN 109553109B CN 201710888891 A CN201710888891 A CN 201710888891A CN 109553109 B CN109553109 B CN 109553109B
- Authority
- CN
- China
- Prior art keywords
- silica sol
- silicon
- silicon source
- alkaline catalyst
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
- C01B33/141—Preparation of hydrosols or aqueous dispersions
- C01B33/1412—Preparation of hydrosols or aqueous dispersions by oxidation of silicon in basic medium
Abstract
The invention discloses a method for preparing silica sol, which comprises the following steps: (1) adding an alkaline catalyst or an alkaline catalyst aqueous solution into a mixture of a silicon source containing simple substance silicon and water; (2) and introducing direct current in the reaction process to generate silica sol. The method provides hydroxide ions by adding an alkaline catalyst, promotes water to ionize to generate the hydroxide ions, so that the initial reaction speed of simple substance silicon and the hydroxide ions is initiated, and direct current is introduced in the reaction process of silicon and water to accelerate the hydrolysis reaction speed of the silicon and generate the silica sol. In the preparation method, direct current is introduced to accelerate the hydrolysis reaction speed of silicon, so that the mass of the alkaline catalyst used in the step (1) is small relative to that of a silicon source, the cation content in the finally prepared silica sol is low, and the amount of the cations of the alkaline catalyst adsorbed on the hydroxyl groups of the silica sol shell is reduced.
Description
Technical Field
The invention belongs to the technical field of silica sol preparation, and particularly relates to a method for preparing silica sol and the silica sol.
Background
During the production of polysilicon, some fine-grained silica slag is produced, which cannot meet the customer's requirements in size and thus cannot be sold and used efficiently. Meanwhile, the fine silicon slag not only causes pollution to the working environment, but also pollutes qualified products. In the actual production process, in order to prevent the polycrystalline silicon quality and the working environment from being polluted, the silicon slag is simply collected and not effectively utilized, so that certain resource waste is caused.
Silica sol is a colloidal solution of amorphous silica particles uniformly dispersed in water. The surface of the silicon dioxide particles in the silica sol contains a large amount of hydroxyl groups, has high reaction activity, can be dissolved with organic polymers through surface modification, and is widely applied to the industries of coating, precision casting, papermaking, spinning, electronics and the like. High purity silica sols are used to improve certain properties of polishing solutions and specialty coatings. Since the common silica sol contains alkali metal ion impurities such as sodium and potassium, which have negative effects during the use and are not beneficial to the use of polishing solution and coating, the concentration of the alkali metal ion needs to be controlled, generally below 10 ppm.
The existing preparation method of the high-purity silica sol comprises the following steps: (1) the method is characterized by taking water glass as a raw material for synthesis: ion exchange is carried out on strong-alkaline water glass with certain concentration through cation resin to convert the water glass into acidic silica sol, then the silica sol reacts with strong-alkaline water solution or alkaline silicate, and the acidic silica sol is converted into alkaline silica sol through nucleation, particle size growth and the like; (2) using hydrolytic organic silane as raw material: the silica sol is prepared by direct hydrolytic polymerization of ethyl orthosilicate/methyl orthosilicate in solution of water and alcohol under the condition of strong base catalyst. The disadvantage of synthesizing high-purity silica sol by using water glass as a raw material is that the product contains a certain amount of metal impurities and cannot be completely removed; the disadvantage of using hydrolytic organosilane as raw material to synthesize high-purity silica sol is that the product needs to be used in strong alkaline environment, the cost is high and the product concentration is low.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a method for preparing silica sol and silica sol aiming at the defects in the prior art, and solve the technical problem that in the prior art, a strong basic catalyst is used too much to introduce too much metal impurities in the process of preparing silica sol.
The technical scheme adopted for solving the technical problem of the invention is to provide a method for preparing silica sol, which comprises the following steps:
(1) adding an alkaline catalyst or an alkaline catalyst solution into a mixture of a silicon source containing simple substance silicon and water;
(2) and introducing direct current in the reaction process to generate silica sol.
Preferably, the silicon source containing elemental silicon in step (1) is high-purity elemental silicon.
Preferably, a catalytic amount of a basic catalyst or a basic catalyst solution is added in step (1).
The water is a weak electrolyte, a certain ionization balance exists in the water, and under the action of direct current, the ionization balance of the water is broken, more hydrogen ions and hydroxide ions are generated, wherein the hydrogen ions obtain electrons at the cathode to become hydrogen, and the hydroxide ions lose the electrons at the anode to become oxygen. The simple substance silicon hydrolysis reaction is the reaction of silicon and ionized water to generate silica sol.
Preferably, the silicon source is silicon slag generated in the production process of polycrystalline silicon; the main component of the silicon slag is simple substance silicon. The silicon slag generated in the production process of the polycrystalline silicon is used as a silicon source for preparing the silica sol, so that the silicon slag in the production process of the polycrystalline silicon can be effectively utilized, the economic benefit of an enterprise is improved, waste is changed into valuable, the post-treatment cost of the silicon slag is saved, and the raw material cost for preparing the silica sol is saved.
The solute in the alkaline catalyst or alkaline catalyst solution is sodium hydroxide and/or potassium hydroxide.
Preferably, the particle size of the silicon source is 10 to 200 meshes.
Preferably, the pH value of the solution of the alkaline catalyst is 10-14.
Preferably, step (1) is preceded by step (i) of cleaning the silicon source so that the impurity content in the silicon source is less than or equal to 1ppm and the purity of silicon is more than or equal to 99.9999 mas%;
the water in the mixture is ultrapure water.
Preferably, the step (i) is specifically:
adding a silicon source into ultrapure water, and carrying out ultrasonic cleaning;
soaking the silicon source which is cleaned by the ultrasonic wave in an acid solution for cleaning, and removing stains on the surface of the silicon source;
and adding the silicon source after acid washing into ultrapure water, firstly carrying out ultrasonic cleaning, and then adding the silicon source into the ultrapure water for rinsing until the ultrapure water is neutral.
Preferably, the step (1) further comprises heating a mixture of a silicon source containing elemental silicon and water to 70-95 ℃. Preferably, the mass ratio of the silicon source to the water in the step (1) is 1: (20-200).
Preferably, in the step (1), the mass ratio of the solute in the basic catalyst or the basic catalyst solution to the elemental silicon in the silicon source is 1: (500-2000). In the preparation method of the present invention, the amount of the basic catalyst used is small relative to the mass of the silicon source, so that the cation content of the basic catalyst in the finally prepared silica sol is small. In the prior art, the mass ratio of an alkaline catalyst used for generating silica sol to simple substance silicon in a silicon source is 1: (50-200).
Preferably, the voltage of the direct current in the step (2) is 1.5-12V.
Preferably, the reaction time in the step (2) is 8 to 12 hours.
Preferably, the step (2) is followed by the step (3) of concentrating at 90-95 ℃ to obtain the concentrated high-purity silica sol. The metal ion content in the high-purity silica sol is less than 10 ppm.
The invention also provides silica sol, which is prepared by the method. The cation content of alkali metal in the silica sol obtained by the preparation method is less than 10 ppm.
According to the method for preparing the silica sol, hydroxide ions are provided by adding the alkaline catalyst, so that the initial reaction speed of simple substance silicon and the hydroxide ions is initiated, direct current is introduced in the reaction process of silicon and water, so that water is promoted to be ionized to generate the hydroxide ions, the hydrolysis reaction speed of silicon is accelerated, and the silica sol is generated. According to the preparation method, direct current is introduced to increase ionization of water, so that the hydrolysis reaction speed of silicon is accelerated, the using amount of the alkaline catalyst can be reduced, the conversion rate of silicon reacting to generate silica sol can be improved, and the reaction speed is improved. The silica sol prepared by the method has high purity, the operation process is simple and convenient, and the purity is easy to control.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present invention, the present invention will be further described in detail with reference to the following detailed description.
Example 1
The embodiment provides a method for preparing silica sol, which comprises the following steps:
(1) adding the collected silicon slag generated in the production process of the polycrystalline silicon into ultrapure water, and carrying out ultrasonic cleaning for 0.5 hour to remove impurities adhered in the silicon slag, wherein the particle size of the silicon slag is 10 meshes; the silicon slag generated in the production process of the polycrystalline silicon is used as a silicon source for preparing the silica sol, so that the silicon slag in the production process of the polycrystalline silicon can be effectively utilized, the economic benefit of an enterprise is improved, waste is changed into valuable, the post-treatment cost of the silicon slag is saved, and the raw material cost for preparing the silica sol is saved.
(2) Soaking the silicon slag subjected to ultrasonic cleaning in an acid solution, and cleaning for 0.5 hour to remove pollutants on the surface of the silicon slag, wherein the acid solution is an aqueous solution of nitric acid and hydrofluoric acid, and the pH value is 5;
(3) adding the silicon slag after acid cleaning into ultrapure water, firstly carrying out ultrasonic cleaning for 0.5 hour, then adding the silicon slag into the ultrapure water again for rinsing for 30 minutes to remove the acid remained on the surface of the silicon slag, wherein the impurity content in the cleaned silicon slag is less than or equal to 1ppm, and the purity of silicon is more than 99.9999 mas%;
(4) adding the cleaned silicon slag into ultrapure water, mixing and stirring to obtain a mixture, placing the mixture on an electromagnetic stirrer for heating and stirring, wherein the mass ratio of the silicon slag to the ultrapure water is 1: 20,
(5) adding an alkaline catalyst into ultrapure water to prepare a required alkaline catalyst solution, wherein the alkaline catalyst is sodium hydroxide, and the pH value is 10;
(6) after the temperature of the mixture of the silicon slag and the ultrapure water is raised to 95 ℃, slowly adding an alkaline catalyst solution, reacting silicon with water, wherein the mass ratio of an alkaline catalyst in the alkaline catalyst solution to the silicon slag is 1: 500, a step of; in the preparation method of this example, the catalyst used was small in mass relative to the silicon source, so that the cation content of the basic catalyst in the finally obtained silica sol was small.
(7) And when the addition amount of the alkaline catalyst solution is more than half, introducing direct current into the ultrapure water, wherein the voltage of the direct current is 9V, reacting for 12 hours after the alkaline catalyst solution is dropwise added, and filtering if unreacted filter residues exist to obtain a filtrate.
(8) The filtrate was stirred in a water bath, heated to 85 ℃ and evaporated for 2 hours to obtain silica sol containing 8ppm of sodium ions and 20 mas% of silica.
The embodiment also provides a silica sol, which is prepared by the method.
In the method for preparing silica sol of the embodiment, hydroxide ions are provided by adding an alkaline catalyst, so that the initial reaction speed of simple substance silicon and the hydroxide ions is initiated, direct current is introduced in the reaction process of silicon and water to promote water to be ionized to generate the hydroxide ions, the hydrolysis reaction speed of silicon is accelerated, and silica sol is generated. According to the preparation method, direct current is introduced to increase ionization of water, so that the hydrolysis reaction speed of silicon is accelerated, the using amount of the alkaline catalyst can be reduced, the conversion rate of silicon reacting to generate silica sol can be improved, and the reaction speed is improved. The silica sol prepared by the method has high purity, the operation process is simple and convenient, and the purity is easy to control.
Example 2
The embodiment provides a method for preparing silica sol, which comprises the following steps:
(1) adding the collected silicon slag generated in the production process of the polycrystalline silicon into ultrapure water, and carrying out ultrasonic cleaning for 1.5 hours to remove impurities adhered to the silicon slag, wherein the particle size of the silicon slag is 100 meshes;
(2) soaking the silicon slag subjected to ultrasonic cleaning in an acid solution, and cleaning for 1 hour to remove pollutants on the surface of the silicon slag, wherein the acid solution is an aqueous solution of nitric acid and hydrofluoric acid, and the pH value is 3;
(3) adding the silicon slag after acid cleaning into ultrapure water, firstly carrying out ultrasonic cleaning for 1 hour, then adding the silicon slag into the ultrapure water again for rinsing for 30 minutes, and removing the acid remained on the surface of the silicon slag, wherein the impurity content in the cleaned silicon slag is less than or equal to 1ppm, and the purity of silicon is more than 99.9999 mas%;
(4) adding the cleaned silicon slag into ultrapure water, mixing and stirring to obtain a mixture, placing the mixture on an electromagnetic stirrer for heating and stirring, wherein the mass ratio of the silicon slag to the ultrapure water is 1: 100, respectively;
(5) adding an alkaline catalyst into ultrapure water to prepare a required alkaline catalyst solution, wherein the alkaline catalyst is potassium hydroxide, and the pH value is 12;
(6) after the temperature of the mixture of the silicon slag and the ultrapure water is raised to 85 ℃, slowly adding an alkaline catalyst solution, reacting silicon with water, wherein the mass ratio of an alkaline catalyst in the alkaline catalyst solution to the silicon slag is 1: 1000, parts by weight;
(7) when the addition amount of the alkaline catalyst solution is more than half, introducing direct current into the ultrapure water, wherein the voltage of the direct current is 6V, reacting for 9 hours after the alkaline catalyst solution is low-priced, and filtering if unreacted filter residues exist to obtain a filtrate;
(8) the filtrate was stirred in a water bath, heated to 90 ℃ and evaporated and concentrated for 3 hours to obtain silica sol containing 8ppm of potassium ions and 10 mas% of silica.
The embodiment also provides a silica sol, which is prepared by the method.
Example 3
The embodiment provides a method for preparing silica sol, which comprises the following steps:
(1) adding the collected silicon slag generated in the production process of the silicon source polycrystalline silicon into ultrapure water, and carrying out ultrasonic cleaning for 3 hours to remove impurities adhered in the silicon slag, wherein the particle size of the silicon slag is 200 meshes;
(2) soaking the silicon slag subjected to ultrasonic cleaning in an acid solution, and cleaning for 2 hours to remove pollutants on the surface of the silicon slag, wherein the acid solution is an aqueous solution of nitric acid and hydrofluoric acid, and the pH value is 1;
(3) adding the silicon slag after acid cleaning into ultrapure water, firstly carrying out ultrasonic cleaning for 1 hour, then adding the silicon slag into the ultrapure water again for rinsing for 30 minutes, and removing the acid remained on the surface of the silicon slag, wherein the impurity content in the cleaned silicon slag is less than or equal to 1ppm, and the purity of silicon is more than 99.9999 mas%;
(4) adding the cleaned silicon slag into ultrapure water, mixing and stirring to obtain a mixture, placing the mixture on an electromagnetic stirrer for heating and stirring, wherein the mass ratio of the silicon slag to the ultrapure water is 1: 200 of a carrier;
(5) after the temperature of the mixture of the silicon slag and the ultrapure water is raised to 75 ℃, slowly adding an alkaline catalyst with the pH value of 14, wherein the alkaline catalyst is a mixture of sodium hydroxide and potassium hydroxide (the mass ratio of the sodium hydroxide to the potassium hydroxide is 1:1), reacting silicon with water, and the mass ratio of the alkaline catalyst to the silicon slag is 1: 2000;
(6) when the addition amount of the alkaline catalyst solution is more than half, introducing direct current into the ultrapure water, wherein the voltage of the direct current is 3V, reacting for 8 hours after the alkaline catalyst solution is low-priced, and filtering if unreacted filter residues exist to obtain a filtrate;
(7) the filtrate was stirred in a water bath, heated to 95 ℃ and evaporated and concentrated for 4 hours to prepare a silica sol containing 3ppm of total sodium ions and potassium ions and 8 mas% of silica.
Certainly, the silicon source in step (1) in this embodiment may also be high-purity elemental silicon, and the silicon source may be high-purity elemental silicon, which may not be washed with water, and the purity of the high-purity elemental silicon is 99.9999 mas% or more.
The embodiment also provides a silica sol, which is prepared by the method.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.
Claims (11)
1. A method for preparing a silica sol, comprising the steps of:
(1) adding an alkaline catalyst or an alkaline catalyst solution into a mixture of a silicon source containing simple substance silicon and water;
(2) introducing direct current in the reaction process to generate silica sol;
wherein the mass ratio of solute in the alkaline catalyst or alkaline catalyst solution to simple substance silicon in the silicon source is 1: (500-2000).
2. The method for preparing silica sol according to claim 1, wherein the silicon source is silica slag generated in the production process of polycrystalline silicon;
the solute in the alkaline catalyst or alkaline catalyst solution is sodium hydroxide and/or potassium hydroxide.
3. The method for preparing silica sol according to claim 1 or 2, wherein the silicon source has a particle size of 10 to 200 mesh.
4. The method for preparing silica sol according to claim 1, wherein the step (1) is preceded by a step (i) of washing the silicon source so that the silicon source has an impurity content of 1ppm or less.
5. The method for preparing silica sol according to claim 4, wherein the step (i) is specifically:
adding a silicon source into ultrapure water, and carrying out ultrasonic cleaning;
soaking the silicon source which is cleaned by the ultrasonic wave in an acid solution for cleaning, and removing stains on the surface of the silicon source;
and adding the silicon source after acid washing into the ultrapure water, firstly carrying out ultrasonic cleaning, and then adding the silicon source into the ultrapure water again for rinsing.
6. The method for preparing silica sol according to claim 1, wherein the step (1) further comprises heating a mixture of a silicon source containing elemental silicon and water to 70-95 ℃.
7. The method for preparing silica sol according to claim 1, wherein the mass ratio of the silicon source to the water in the step (1) is 1: (20-200).
8. The method for preparing silica sol according to claim 1, wherein the voltage of the direct current in the step (2) is 1.5 to 12V.
9. The method for preparing silica sol according to claim 8, wherein the reaction time in the step (2) is 8 to 12 hours.
10. The method for preparing silica sol according to claim 1, wherein the step (2) is followed by the step (3) of concentrating at 90-95 ℃ to obtain the concentrated high-purity silica sol.
11. A silica sol produced by the method according to any one of claims 1 to 10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710888891.2A CN109553109B (en) | 2017-09-27 | 2017-09-27 | Method for preparing silica sol and silica sol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710888891.2A CN109553109B (en) | 2017-09-27 | 2017-09-27 | Method for preparing silica sol and silica sol |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109553109A CN109553109A (en) | 2019-04-02 |
| CN109553109B true CN109553109B (en) | 2021-01-22 |
Family
ID=65863547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710888891.2A Active CN109553109B (en) | 2017-09-27 | 2017-09-27 | Method for preparing silica sol and silica sol |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109553109B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112299423B (en) * | 2019-08-01 | 2022-06-28 | 新特能源股份有限公司 | Silicon dioxide preparation method and prepared silicon dioxide |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61242910A (en) * | 1985-04-18 | 1986-10-29 | Isao Sakai | Production of active silicic acid sol |
| CN102849748A (en) * | 2012-08-25 | 2013-01-02 | 安阳市凤凰光伏科技有限公司 | One-step method for preparing silica sol from silicon |
-
2017
- 2017-09-27 CN CN201710888891.2A patent/CN109553109B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109553109A (en) | 2019-04-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104817059A (en) | Method for preparing battery-grade iron phosphate from reaction between iron powder and phosphoric acid | |
| CN103011453A (en) | Processing method for fluoride waste water in production of solar cells | |
| CN101428805B (en) | Utilization technology for fluorine-containing white residue | |
| CN103979548A (en) | New method for producing fluoride and white carbon black by adopting fluosilicic acid or fluosilicate | |
| JPH0796447B2 (en) | Method for producing high-purity silica | |
| CN105036081A (en) | Method for producing HCl gas through chlorosilane residual liquor | |
| CN104843712A (en) | Industrial fluosilicic acid purification and white carbon black co-production method | |
| CN109553109B (en) | Method for preparing silica sol and silica sol | |
| CN111115672A (en) | Method for recycling nitric acid, hydrofluoric acid and acetic acid mixed acid | |
| US20030005724A1 (en) | Method for producing silica particles, synthetic quartz powder and synthetic quartz glass | |
| CN104843721A (en) | Organic silicon waste contact recovery method | |
| CN107083168B (en) | A kind of glass nano transparent insulating coating and its application | |
| CN108249449A (en) | The circulation utilization method of pickle liquor in a kind of glass sand subtractive process | |
| JP2007176710A (en) | Method for producing antimony oxide sol and antimony oxide sol | |
| CN104773749A (en) | Method for preparing high-purity calcium fluoride in ethanol system | |
| CN1225897A (en) | Production of high molecular-ration cryolite by sodium-fluorosilicate sodium-aluminate method | |
| CN107540234B (en) | Method for discharging glass thinning system without waste acid and glass slag | |
| CN104860322B (en) | A kind of preparation method of low sodium ions content high-purity silicasol | |
| CN1363511A (en) | Process for preparing fluorine compound and SiO2 from sodium fluosilicate | |
| CN110180492B (en) | Active filter material for removing magnesium ions, and preparation method and application thereof | |
| CN111348634B (en) | Preparation method of layered alpha-titanium phosphate | |
| CN109647410B (en) | Preparation method of supported expanded graphite catalyst for treating EDTA-Cu wastewater | |
| CN103848460B (en) | The rear silicon removing method of a kind of Steel Plant spent pickle liquor regeneration byproduct brown iron oxide | |
| CN113371720A (en) | Method for preparing white carbon black by adding sulfuric acid into fluorine-containing silicon slag through dry impurity removal | |
| CN110227489A (en) | A kind of high quantum conversion ratio photochemical catalyst of nanoscale and its preparation process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20200408 Address after: 831500 6th floor, R & D building, 2249 Zhongxin street, ganquanbao economic and Technological Development Zone (Industrial Park), Urumqi high tech Industrial Development Zone, Xinjiang Uygur Autonomous Region Applicant after: Xinjiang silicon based new material innovation center Co., Ltd Address before: 830011, the Xinjiang Uygur Autonomous Region Urumqi national hi tech Industrial Development Zone (new urban area) Ganquan Fort High-tech Industrial Park Applicant before: XINTE ENERGY Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |