CN-121651373-B - Efficient deep removal method for quartz sand inclusion impurities

Abstract

The invention relates to a high-efficiency deep removal method for quartz sand inclusion impurities, and belongs to the technical field of high-purity quartz high-efficiency preparation and nonmetallic ore deep processing. The method comprises the steps of mixing quartz sand raw materials with insulating liquid to form slurry, carrying out N-stage high-voltage pulse treatment on the slurry to obtain intermediate quartz sand, carrying out acid leaching treatment on solid obtained after solid-liquid separation on the intermediate quartz sand, wherein N is more than or equal to 2, N is an integer, the pulse voltage of the N-1-stage high-voltage pulse treatment is larger than that of the N-stage high-voltage pulse treatment, the highest pulse voltage of the first-stage high-voltage pulse treatment is not higher than 500kV, the lowest pulse voltage of the N-stage high-voltage pulse treatment is not lower than 50 kV, and obtaining the high-purity quartz sand. The invention creatively combines the selective crushing of high-voltage electric pulses with more than 2 levels with the mild chemical acid leaching technology to construct a high-efficiency synergistic process system, thereby realizing the targeted deep removal of inclusion impurities in quartz sand.

Inventors

• SUN ZENGQING
• CHEN XULING
• HUANG XIAOXIAN
• FAN XIAOHUI
• ZENG YAOYING
• LI XIAOYU
• GAN MIN
• JI ZHIYUN
• FENG ZHENXIANG
• WEI JIAOYANG
• LI SHUAIJUN

Assignees

• 中南大学

Dates

Publication Date

20260508

Application Date

20260206

Claims (9)

1. 1. A method for efficiently and deeply removing impurities in a quartz sand inclusion is characterized by comprising the following steps: (1) Mixing quartz sand raw materials with insulating liquid to form slurry; (2) Performing N-level high-voltage pulse treatment on the slurry to obtain intermediate quartz sand, wherein N is more than or equal to 2, N is an integer, the pulse voltage of the N-1-level high-voltage pulse treatment is larger than that of the N-level high-voltage pulse treatment, the highest pulse voltage of the first-level high-voltage pulse treatment is not higher than 500kV, the lowest pulse voltage of the N-level high-voltage pulse treatment is not lower than 50 kV, and the voltage difference between the pulse voltage of the N-level high-voltage pulse treatment and the pulse voltage of the N-1-level high-voltage pulse treatment is 110-300 kV; (3) And carrying out solid-liquid separation on the intermediate quartz sand, and then taking a solid for acid leaching treatment to obtain the high-purity quartz sand.
2. 2. The method for removing impurities from quartz sand inclusion efficiently and deeply according to claim 1, wherein the conductivity of the insulating liquid is lower than 30 mu S/cm.
3. 3. The method for efficiently and deeply removing impurities from quartz sand inclusion according to claim 1 or 2, wherein the pulse width of each stage of high-voltage pulse treatment is 100 ns-2 μs independently, and the pulse repetition frequency is 20-300 Hz independently.
4. 4. The method for removing impurities from quartz sand inclusion with high efficiency and depth according to claim 1 or 2, wherein N is 2 or 3; When N is 2, the pulse voltage of the 1 st-stage high-voltage pulse treatment is 280 kV-500 kV, and the pulse voltage of the 2 nd-stage high-voltage pulse treatment is 150 kV-250 kV; When N is 3, the pulse voltage of the 1 st-stage high-voltage pulse treatment is 400 kV-500 kV, the pulse voltage of the 2 nd-stage high-voltage pulse treatment is 180 kV-250 kV, and the pulse voltage of the 3 rd-stage high-voltage pulse treatment is 50 kV-120 kV.
5. 5. The method for efficiently and deeply removing impurities in quartz sand inclusion according to claim 3, wherein the insulating liquid is deionized water and/or high-purity ethanol with ethanol content not less than 99.5 wt%.
6. 6. The method for efficiently and deeply removing impurities in quartz sand inclusion according to claim 1 or 2, wherein the mass ratio of the quartz sand raw material to the insulating liquid is 1:3-8.
7. 7. The method for efficiently and deeply removing impurities in quartz sand inclusion according to claim 1 or 2, wherein the content of SiO 2 in the quartz sand raw material is more than or equal to 99.5%, and the granularity of the quartz sand raw material is 70-350 μm.
8. 8. The method for removing impurities from quartz sand inclusion with high efficiency and depth according to claim 1 or 2, wherein the acid treated by acid leaching is at least one selected from hydrochloric acid, hydrofluoric acid, sulfuric acid, nitric acid and oxalic acid; And/or the acid concentration of the acid leaching treatment is 5-15wt%, the temperature is 20-90 ℃, the solid-liquid mass ratio is 1:3-10, and the time is 0.5-4 h.
9. 9. The method for efficiently and deeply removing impurities in quartz sand inclusion according to claim 1 or 2, wherein the content of SiO 2 in the high-purity quartz sand is more than or equal to 99.99%.

Description

Efficient deep removal method for quartz sand inclusion impurities Technical Field The invention relates to a high-efficiency deep removal method for quartz sand inclusion impurities, and belongs to the technical field of high-purity quartz high-efficiency preparation and nonmetallic ore deep processing. Background The high-purity quartz sand is an essential key base material for the industries of semiconductors, photovoltaics, optical communication and the like, and is widely used for preparing key devices such as quartz crucibles, optical fiber preformed bars and the like. With the rapid development of global energy transformation and digital economy, the market is increasingly pressing on high-purity quartz sand, especially on high-end products with excellent thermal stability and low impurity precipitation capability, and the quality requirements are also becoming severe. However, the quartz ore deposit capable of directly meeting the high-end application is extremely rare, and the global supply is highly concentrated, so that the efficient and universal quartz sand deep purification technology is continuously developed, and the safety of the industry supply chain emerging from the strategy of China is ensured. Inclusion impurity removal is an important difficulty in quartz sand purification. The inclusion in the quartz sand is mainly fluid inclusion, is a tiny gas-liquid bubble sealed in the quartz crystal growing process, and is usually dissolved with impurity ions such as potassium, sodium, iron and the like. These inclusions are firmly locked inside the quartz, creating a physical difference with the quartz body. In order to solve the difficult problem of inclusion removal, various researches are carried out in the industry and academia, but the problems have obvious limitations. The high-temperature bursting method is a common means, and the principle is that fluid inclusion in quartz is heated and gasified by high-temperature roasting, and the volume of the fluid inclusion is rapidly expanded, so that the inclusion wall is broken or microcracks are generated. In order to improve the explosion effect of inclusion, high-temperature roasting and water quenching are often combined. The method has a certain effect on partial fluid inclusion, but has the problems of high energy consumption and high production cost. Meanwhile, the high-temperature heat treatment is easy to cause irreversible phase change of quartz crystal lattice or generate thermal stress cracks, and the key performances such as high-temperature stability and the like of the quartz crystal lattice are damaged. Direct strong acid leaching is another method that is often mentioned, i.e. the use of high concentrations of mixed acids to soak quartz sand at high temperatures for long periods of time in an attempt to dissolve impurities by the corrosive action of the acid. However, this method acts mainly on surface impurities, and the removal efficiency of the internal inclusion is extremely low. In recent years, high-voltage electric pulse crushing technology is attracting attention as an emerging material pretreatment method due to its unique selective crushing potential. The basic principle is that under the action of high voltage pulse, breakdown current locally generates shock wave by utilizing the differences of physicochemical properties such as dielectric constants, conductivities and the like of different minerals, so that the selective action of energy at a target interface is realized. It was found that this technique can induce microcracking inside the quartz particles or locally rupture inclusions. However, the application of this technique alone to silica sand purification still faces the bottleneck that, on the one hand, high-voltage electric pulses can effectively open the inclusion or create cracks between it and the silica matrix, but it is difficult to remove the impurities that have been exposed, especially in the inclusion, by means of physical shock waves alone, and on the other hand, if the pulse energy is excessively increased in order to pursue the removal of the impurities, excessive pulverization of the silica particles themselves is caused, reducing the yield of the target fraction. Chinese patent (publication No. CN 120622497A) discloses a method and a device for removing gas-liquid inclusion in quartz sand, the method comprises the following steps of S1, roasting raw quartz ore, S2, carrying out water quenching and high-voltage electric pulse treatment on the roasted quartz ore obtained in S1, and S3, purifying the quartz ore obtained in S2 to obtain high-purity quartz sand. The method needs to carry out roasting treatment firstly, the roasting pretreatment has the defect of high energy consumption, the secondary pollution possibility of materials exists in the water quenching process of the roasted quartz, and the treatment flow of the method is long. Disclosure of Invention Aiming at the problems that in the p