WO2020228115A1

WO2020228115A1 - Quartz powder and preparation method therefor

Info

Publication number: WO2020228115A1
Application number: PCT/CN2019/094787
Authority: WO
Inventors: 范艳层; 钱宜刚; 沈一春; 丁杰
Original assignee: 中天科技精密材料有限公司
Priority date: 2019-05-14
Filing date: 2019-07-05
Publication date: 2020-11-19
Also published as: CN111943215B; CN111943215A

Abstract

Provided are quartz powder and a preparation method therefor. The preparation method comprises: hydrolyzing SiCl ₄ and water at a preset volume ratio to obtain silicic acid gel of a spatial network structure, and then aging the silicic acid gel; performing primary drying on the moisture on the surface and the moisture in structure voids of the silicic acid gel in a first temperature range to obtain material 1; performing secondary drying on material 1 in a second temperature range for dehydration to obtain material 2; and calcining material 2 to obtain quartz powder. The introduction of other impurities is avoided by using SiCl ₄ and water as main raw materials, and the agglomeration of powder is prevented by means of a multiple drying technology, thus moisture can be fully eliminated and high-purity quartz powder having reduced hydroxyl content can be prepared.

Description

Quartz powder and its preparation method

Technical field

The invention relates to the technical field of material preparation, in particular to a quartz powder and a preparation method thereof.

Background technique

This section is intended to provide background or context for the embodiments of the present invention stated in the claims. The description here is not recognized as prior art just because it is included in this section.

Quartz sand is mainly used in IC integrated circuits and quartz glass industries, and its high-end products are widely used in large-scale and ultra-large-scale integrated circuits, optical fibers, lasers, aerospace, military and other fields. As the requirements for the purity of quartz sand in semiconductor crucibles and integrated circuits become higher and higher, natural quartz sand is gradually eliminated due to problems such as uneven purity and resource depletion. It is urgent to develop high-purity synthetic quartz powder.

The existing high-purity quartz powder preparation includes using water glass as a raw material to prepare synthetic quartz powder, which requires cation exchange resin to remove alkali metal ions; and using alkoxysilane as a raw material to prepare synthetic quartz powder, but it is easy to introduce carbon elements. May cause bubbles to be generated. These methods use alkoxysilane or water glass as raw materials. On the one hand, impurities such as carbon element or alkali metal ions may be introduced, causing the quartz glass to easily produce bubbles or low viscosity; on the other hand, the removal of impurities is complicated.

Summary of the invention

In view of the above, it is necessary to provide an improved method for preparing quartz powder.

The technical solution provided by the present invention is: a method for preparing quartz powder, including the following steps:

Hydrolysis reaction of SiCl ₄ and water in a preset volume ratio to obtain a silicic acid gel with a spatial network structure, and then aging;

Dry the moisture on the surface of the silicic acid gel and the moisture in the structural voids next time in the first temperature range to obtain material 1;

Material 1 is dried for a second time in the second temperature range for dehydration to obtain material 2;

The material 2 is calcined to obtain quartz powder.

Further, the temperature range of the first temperature interval is 100-300°C.

Further, the step of drying the water in the voids of the silicic acid gel structure at the first temperature interval to obtain the material 1 includes:

The surface moisture of the silicic acid gel and the 70-90% of the filling moisture in the structural voids are dried in the first temperature range, and the duration of one drying is in the range of 1-20 h to obtain material 1.

Further, the temperature range of the second temperature interval is 700-1000°C.

Further, the step of drying the material 1 in the second temperature range for dehydration to obtain the material 2 includes:

The duration of the secondary drying is in the range of 1-10 h, and the moisture in the dehydration includes the remaining filling moisture and the reaction water from which the hydroxyl group is eliminated.

Further, the volume ratio of SiCl _{4 to} water ranges from 1:3-1:12.

Further, the aging time range is 10-50h.

Further, the calcination time range is 0.5-10h. The function of the calcination step is to eliminate pores in the gel and make it dense.

Further, the step of obtaining quartz powder from the calcined material 2 includes:

The material 2 is calcined in a vacuum atmosphere to obtain quartz powder.

Further, the air pressure control range during the calcination process is 10-100 Pa.

The invention also provides a quartz powder, which is formed by adopting the preparation method of the quartz powder.

Further, the quartz powder is high-purity quartz with a purity of not less than 99.9999%.

Further, the metal impurity content in the quartz powder is 0.08-0.99 ppm, and the hydroxyl content is 8-50 ppm.

Further, the content of metal impurities in the quartz powder is 0.09 ppm.

Further, the hydroxyl content in the quartz powder is 10 ppm.

Compared with the prior art, the method for preparing quartz powder provided by the present invention uses SiCl ₄ as a raw material to avoid the introduction of other impurities, and uses multiple drying techniques to prevent powder agglomeration, fully eliminate moisture and reduce hydroxyl groups. Content, made of high-purity quartz powder.

Description of the drawings

The present invention will be further described in detail below with reference to the drawings and specific embodiments.

Fig. 1 is a flow chart of the preparation of quartz powder in an embodiment of the present invention.

Description of reference signs:

no.

The following specific embodiments will further illustrate the embodiments of the present invention in conjunction with the above-mentioned drawings.

Detailed ways

In order to be able to understand the above objectives, features and advantages of the embodiments of the present invention more clearly, the present invention will be described in detail below with reference to the accompanying drawings and specific implementations. It should be noted that, if there is no conflict, the features in the embodiments of the present application can be combined with each other.

In the following description, many specific details are set forth in order to fully understand the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the embodiments of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the embodiments of the present invention. The terminology used in the specification of the present invention herein is only for the purpose of describing specific embodiments, and is not intended to limit the embodiments of the present invention.

Please refer to Fig. 1, which is a preparation process of quartz powder in a preferred embodiment of the present invention. The main steps include:

Step S1: Hydrolyze the SiCl ₄ with a preset volume ratio and water to obtain a silicic acid gel with a spatial network structure, and then age.

In this embodiment, the volume ratio of SiCl _{4 to} water ranges from 1:3-1:12; the aging time ranges from 10 to 50 hours. Among them, the choice of water focuses on the reaction water with low impurity ion content, especially the metal ion should be ppb level, as long as it meets the impurity ion concentration requirements, such as deionized water, distilled water and so on.

Step S2: drying the moisture on the surface of the silicic acid gel and the structural voids in the first temperature range once to obtain material 1.

In this embodiment, step S2 is specifically drying the surface moisture of the silicic acid gel and the 70-90% of the filling moisture in the structural voids in the first temperature range for one time, wherein the duration of one drying is in the range of 1-20h to obtain Material 1. Wherein, the temperature range of the first temperature interval is 100-300°C. The purpose of this step is to avoid agglomeration of the calcined quartz powder.

Step S3: the material 1 is dried for a second time in the second temperature range for dehydration, and the material 2 is obtained.

In this embodiment, the temperature range of the second temperature interval is 700-1000°C. The duration of the secondary drying is in the range of 1-10 h, and the moisture in the dehydration includes the remaining filling moisture and the reaction water from which the hydroxyl group is eliminated.

Step S4: calcining material 2 to obtain quartz powder.

In this embodiment, the calcination time range is 0.5-10h. The function of the calcination step is to eliminate pores in the gel and make it dense. Step S4 is specifically calcining the material 2 in a vacuum atmosphere to obtain quartz powder, wherein the air pressure control range during the calcining process is 10-100 Pa.

The sequence of the above steps cannot be reversed. Using SiCl ₄ and water as raw materials, the production process will not introduce impurities such as carbon or alkali metals. Multi-step drying is indispensable. One drying effect is to remove the gel surface and voids at low temperature. The free water and bound water in the pores, and the water in the voids are called filling water in this embodiment. By slowly drying the water in the pores of the gel at low temperature, the gel can be prevented from breaking and agglomeration; the second drying is used to remove The hydroxyl group (-OH) and organic matter in the gel structure realize the purification of quartz powder; the function of calcination is to eliminate the pores in the gel and make it dense. The quartz powder prepared by the above method has high purity, and meets the application requirements in the fields of semiconductor crucibles, integrated circuits and the like; and the process steps are simplified, which is conducive to mass industrial production. The obtained quartz powder is of high purity, and the purity of the quartz powder prepared under the above conditions can reach 99.9999% and above after testing.

The following examples illustrate the preparation examples and product properties of the quartz powder of the present invention.

Comparison

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:3 with deionized water, aging for 15 hours, then drying at 700°C for 2 hours, and calcining at 100Pa air pressure and 1400°C for 1 hour. High-purity synthetic quartz powder, the result shows that the quartz powder is seriously agglomerated.

Example 1

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:3 with deionized water, aging for 15 hours, and then drying at a temperature of 300°C for 1 hour, and drying at a temperature of 700°C for a second time for 10 hours, at 100Pa It is calcined at a pressure of 1400°C for 0.5h to obtain high-purity synthetic quartz powder. The product has no agglomeration. The measured metal impurity content is 0.08ppm and the hydroxyl content is 50ppm.

Example 2

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:6 with deionized water, aging for 60 hours, and then drying at a temperature of 150°C for 6 hours and a second drying at a temperature of 800°C for 6 hours, at 80Pa It is calcined at a temperature of 1200°C under air pressure for 8 hours to obtain high-purity synthetic quartz powder without agglomeration. The metal impurity content is measured to be 0.2ppm and the hydroxyl content is 30ppm.

Example 3

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:8 with deionized water, aging for 100 hours, and then drying at a temperature of 120°C for 10 hours, and drying at a temperature of 900°C for a second time for 3 hours at 10Pa It is calcined under air pressure and temperature of 1300°C for 3 hours to obtain high-purity synthetic quartz powder without agglomeration. The measured metal impurity content is 0.5ppm and the hydroxyl content is 10ppm.

Example 4

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:12 and deionized water, aging for 150 hours, and then drying at a temperature of 100°C for 20 hours, and drying at a temperature of 1000°C for 1 hour, at a pressure of 10Pa, 1350 It is calcined at a temperature of ℃ for 1.5 hours to obtain high-purity synthetic quartz powder without agglomeration, and the metal impurity content is 0.99ppm, and the hydroxyl content is 8ppm.

Example 5

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:3 with deionized water, aging for 15 hours, and then drying at a temperature of 120°C for 4 hours and then drying at a temperature of 700°C for 2 hours at 100Pa It is calcined at a pressure of 1400°C for 1 hour, and the obtained high-purity synthetic quartz powder has no agglomeration, and the metal impurity content is 0.98ppm, and the hydroxyl content is 50ppm.

Example 6

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:5 with deionized water, aging for 60 hours, and then drying at a temperature of 150°C for 2 hours and a second drying at a temperature of 800°C for 3 hours, at 80Pa When calcined at a pressure of 1350°C for 2 hours, the high-purity synthetic quartz powder obtained has no agglomeration, and the metal impurity content is 0.5ppm, and the hydroxyl content is 30ppm.

Example 7

The silicic acid gel is obtained by hydrolyzing SiCl ₄ with a volume ratio of 1:6 with deionized water, aging for 100 hours, and then drying at a temperature of 200°C for 1 hour, and drying at a temperature of 900°C for 2 hours, at 10Pa The high-purity synthetic quartz powder obtained was calcined at a pressure of 1300°C for 3 hours without agglomeration, and the metal impurity content was 0.09ppm and the hydroxyl content was 10ppm.

In other embodiments, the volume ratio of SiCl ₄ to water, aging time, primary drying temperature, primary drying time, secondary drying temperature, secondary drying time, air pressure during calcination, calcination temperature, calcination time, etc. It is limited to the above-mentioned embodiment; and the multi-step drying can also be three-step drying or more than three steps, so that the high-purity quartz powder does not agglomerate and the calcination process is more sufficient.

In summary, the quartz powder molded by the method of the present invention has no agglomeration phenomenon and high purity. The metal impurity content is generally 0.08-0.99ppm, and the hydroxyl content is 8-50ppm. Under optimal conditions, the metal impurity content is 0.09ppm and the hydroxyl content is 10ppm. Moreover, the method of the present invention has simplified steps, strong operability, and high mass production efficiency.

The above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and not to limit them. Although the embodiments of the present invention are described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technology of the embodiments of the present invention can be Modifications or equivalent replacements of the solutions should not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

A method for preparing quartz powder is characterized in that it comprises the following steps:

Hydrolysis reaction of SiCl4 and water with a preset volume ratio to obtain a silicic acid gel with a spatial network structure, and then aging;

Dry the moisture on the surface of the silicic acid gel and the moisture in the structural voids in the first temperature range once to obtain material 1;

Material 1 is dried for a second time in the second temperature range for dehydration to obtain material 2;

The material 2 is calcined to obtain quartz powder.
The method for preparing quartz powder according to claim 1, wherein the temperature range of the first temperature interval is 100-300°C.
The method for preparing quartz powder according to claim 1, wherein the step of drying the moisture in the voids of the silicic acid gel structure in the first temperature range to obtain the material 1 comprises:

The surface moisture of the silicic acid gel and the 70-90% of the filling moisture in the structural voids are dried in the first temperature range for one time, wherein the duration of one drying is in the range of 1-20 h, to obtain material 1.
The method for preparing quartz powder according to claim 1, wherein the temperature range of the second temperature interval is 700-1000°C.
The method for preparing quartz powder according to claim 3, wherein the step of drying the material 1 in the second temperature range for dehydration to obtain the material 2 comprises:

The duration of the secondary drying is in the range of 1-10 h, and the moisture in the dehydration includes the remaining filling moisture and the reaction water from which the hydroxyl group is eliminated.
The method for preparing quartz powder according to claim 1, wherein the volume ratio of the SiCl4 to water ranges from 1:3-1:12.
The method for preparing quartz powder according to claim 1, wherein the aging time ranges from 10 to 50 hours.
The method for preparing quartz powder according to claim 1, wherein the calcination time range is 0.5-10h.
The method for preparing quartz powder according to claim 1, wherein the step of calcining the material 2 to obtain quartz powder comprises:

The material 2 is calcined in a vacuum atmosphere to obtain quartz powder.
The method for preparing quartz powder according to claim 9, characterized in that the air pressure control range is 10-100 Pa during the calcination process.
A quartz powder, characterized in that it is formed by the method for preparing quartz powder according to any one of claims 1-10.
The quartz powder of claim 11, wherein the quartz powder is high-purity quartz with a purity of not less than 99.9999%.
The quartz powder according to claim 11, wherein the metal impurity content in the quartz powder is 0.08-0.99 ppm, and the hydroxyl content is 8-50 ppm.
The quartz powder according to claim 11, wherein the content of metal impurities in the quartz powder is 0.09 ppm.
The quartz powder according to claim 11, wherein the content of hydroxyl group in the quartz powder is 10 ppm.