CN-121974360-A - Purification method of high-purity quartz sand

CN121974360ACN 121974360 ACN121974360 ACN 121974360ACN-121974360-A

Abstract

The invention relates to a purification method of high-purity quartz sand, and belongs to the technical field of quartz sand purification. The purification method of the high-purity quartz sand comprises the steps of mixing pretreated quartz sand with a solid halogenating agent (comprising ammonium iodide and ammonium bromide), performing activation roasting under microwave irradiation, bursting inclusion bodies in the quartz sand by utilizing the selective heating effect of microwaves, and promoting impurity elements to react with the solid halogenating agent to generate volatile halides for removal. And then, further purifying the microwave halogenated material by chloridizing with a gas chloridizing agent, and finally obtaining a high-purity quartz sand product by post-treatment. The method of the invention combines gas-solid synergistic halogenation with microwave activation, obviously reduces the activation energy and the reaction temperature of halogenation reaction, improves the removal efficiency of impurities which are difficult to remove such as boron, aluminum, titanium and the like, can purify 99.9 percent of quartz sand to more than 99.99 percent, and has the advantages of low energy consumption and high product purity.

Inventors

LI JIERUI
ZHENG KAI
LI GUANGSHI
Sun Chenteng
LU XIONGGANG
GAO WEIFAN

Assignees

江西硅矿利用核心技术研发投资有限公司

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (10)

1. The purification method of the high-purity quartz sand is characterized by comprising the following steps of: s1, raw material pretreatment, namely pretreating quartz sand raw materials to obtain pretreated quartz sand; S2, mixing the pretreated quartz sand and a solid halogenating agent according to the mass ratio of 100 (0.5-10) to obtain a mixed material, wherein the solid halogenating agent comprises ammonium iodide and ammonium bromide, and the mass ratio of the ammonium iodide to the ammonium bromide is (1-5); S3, microwave halogenation, namely roasting the mixed material by applying microwave irradiation to obtain a microwave halogenated material, wherein the roasting temperature is 500-800 ℃; S4, gas chlorination, namely performing gas chlorinating roasting on the microwave halogenated material to obtain a gas chlorinated material, wherein the roasting temperature is 800-1100 ℃; s5, post-treatment, namely carrying out post-treatment on the gas chlorination material to obtain a high-purity quartz sand finished product.
2. The method for purifying high-purity quartz sand according to claim 1, wherein in the step S1, the quartz sand raw material is subjected to crushing, ore grinding, classification, magnetic separation, floatation, acid leaching and drying treatment to obtain pretreated quartz sand, wherein the granularity of the pretreated quartz sand is 100-250 meshes, and the SiO 2 content is not less than 99.9%.
3. The method for purifying high purity silica sand according to claim 1, wherein in step S2, the solid halogenating agent is a mixture of ammonium iodide and ammonium bromide.
4. The method for purifying high purity silica sand according to claim 1, wherein in step S2, the pretreated silica sand is mixed with a solid halogenating agent and then pressed into a granular mixed material by a dry method, wherein the particle size of the mixed material is 2-10mm.
5. The method for purifying high purity silica sand according to claim 1, wherein the calcination time is 10 to 50 minutes in step S3.
6. The method for purifying high purity silica sand according to claim 1 or 5, wherein in step S3, the mixture is placed in a microwave reactor, and roasting is performed by applying microwave irradiation under an inert atmosphere, wherein the microwave frequency is 2.45GHz, and the power is 2-10kW.
7. The method for purifying high purity silica sand according to claim 1, wherein in step S4, the gaseous chlorinating agent is hydrogen chloride.
8. The method for purifying high purity silica sand according to claim 1, wherein the calcination time is 1 to 4 hours in step S4.
9. The method for purifying high purity silica sand according to claim 1, wherein in step S4, the microwave halogenated material is placed in a gas chlorination furnace and calcined in a mixed atmosphere of hydrogen chloride and an inert gas, wherein the volume concentration of the hydrogen chloride in the mixed atmosphere is 10 to 80%.
10. The method for purifying high purity silica sand according to claim 1, wherein in step S5, the gaseous chlorinated material is cooled, acid-washed, water-washed, and dried to obtain a high purity silica sand finished product.

Description

Purification method of high-purity quartz sand Technical Field The invention relates to the technical field of quartz sand purification, in particular to a purification method of high-purity quartz sand. Background High-purity quartz sand is a key basic material of high-end industries such as semiconductors, photovoltaics, optical fiber communication and the like, and the purity of the high-purity quartz sand directly determines the performance and quality of a final product. However, natural quartz ore is often intergrown with a large amount of impurity minerals and itself also has the drawbacks of fluid inclusions, lattice impurities, etc., making its purification to high-purity to ultra-high purity levels a serious set of technical challenges. After physical mineral separation and acid washing, most of free impurities in the natural quartz sand can be effectively removed, and the purity of the quartz sand can be improved to 99.9% (3N). And the quartz sand with the purity of 99.9 percent (3N) is purified to be more than 99.99 percent (4N), and the core difficulty is that the impurity elements such as Al, B, ti, fe, na, K and the like in the crystal lattice are removed. The traditional chloridizing roasting process is usually carried out at a high temperature of above 1200 ℃ by introducing Cl 2 or HCl atmosphere to convert impurities into chlorides for volatilization and removal. However, the method has high energy consumption, is easy to cause vitrification of the surface of quartz sand, prevents impurities from further escaping, and has serious damage to equipment due to high temperature and corrosive atmosphere (Cl 2). The microwave technology is used as a novel heating mode, has the advantages of selective heating, rapid temperature rise, volumetric heating and the like, and has good application prospect in the field of material treatment. However, how to effectively combine the microwave technology and the chlorination purification technology to realize the low-temperature efficient purification of the high-purity quartz sand is still a technical bottleneck to be broken through in the field. Disclosure of Invention Based on the above, the invention aims to provide a purification method of high-purity quartz sand, which is characterized in that a solid halogenating agent is activated by microwave irradiation, so that the first-stage halogenation purification of quartz lattice impurities is realized, and then the advanced purification is performed by combining a gas chlorinating agent, thereby realizing the efficient preparation of the high-purity quartz sand at a lower temperature. In order to achieve the above purpose, the present invention adopts the following technical scheme: The invention provides a purification method of high-purity quartz sand, which comprises the following steps: s1, raw material pretreatment, namely pretreating quartz sand raw materials to obtain pretreated quartz sand; S2, mixing the pretreated quartz sand and a solid halogenating agent according to the mass ratio of 100 (0.5-10) to obtain a mixed material, wherein the solid halogenating agent comprises ammonium iodide (NH 4 I) and ammonium bromide (NH 4 Br), and the mass ratio of the ammonium iodide to the ammonium bromide is (1-5); S3, microwave halogenation, namely roasting the mixed material by applying microwave irradiation to obtain a microwave halogenated material, wherein the roasting temperature is 500-800 ℃; S4, gas chlorination, namely performing gas chlorinating roasting on the microwave halogenated material to obtain a gas chlorinated material, wherein the roasting temperature is 800-1100 ℃; s5, post-treatment, namely carrying out post-treatment on the gas chlorination material to obtain a high-purity quartz sand finished product. The purification method of the high-purity quartz sand comprises the steps of mixing pretreated quartz sand with a solid halogenating agent (comprising ammonium iodide and ammonium bromide), performing activation roasting under microwave irradiation, bursting inclusion bodies in the quartz sand by utilizing the selective heating effect of microwaves, and promoting impurity elements to react with the solid halogenating agent to generate volatile halides for removal. And then, further purifying the microwave halogenated material by chloridizing with a gas chloridizing agent, and finally obtaining a high-purity quartz sand product by post-treatment. The method of the invention combines gas-solid synergistic halogenation with microwave activation, obviously reduces the activation energy and the reaction temperature of halogenation reaction, improves the removal efficiency of impurities which are difficult to remove such as boron, aluminum, titanium and the like, can purify 99.9 percent of quartz sand to more than 99.99 percent, and has the advantages of low energy consumption and high product purity. According to the purification method of the high-purity quartz sand, in the step S2 microwa