6n grade large particle quartz sand and method for producing the same

Abstract

The application provides 6N-grade large-particle quartz sand and a preparation method thereof, and belongs to the technical field of inorganic non-metallic materials. The method comprises the following steps: adding high-purity water, electronic-grade ammonia water, ultra-pure electronic-grade C1-C2 alcohol and alcohol surfactant into a fluorine-lined reaction container; starting stirring, adding organic silicate into the reaction container drop by drop, performing primary hydrolysis at a first temperature, and then performing deep hydrolysis at a second temperature; the second temperature is higher than the first temperature; after the hydrolysis reaction is completed, silica is separated to obtain quartz sand wet material; after the quartz sand wet material is calcined and crushed, 6N-grade large-particle quartz sand is obtained. The quartz sand prepared by the method has a total amount of metal impurities lower than 100 ppb, a hydroxyl content lower than 10 ppm, and a purity higher than 99.9999%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inorganic non-metallic materials, in particular to the technical field of quartz sand, and specifically relates to 6N-grade large-particle quartz sand and a preparation method thereof. BACKGROUND

[0002] High-purity quartz sand has a SiO2 content of ≥99.99%, and is a material basis for the development of high-tech industries. The application fields of high-purity quartz sand involve the technical field of semiconductors, the military field, the aerospace field and the like. The purity of quartz sand raw materials is extremely strict in these fields, and the content of impurities in quartz sand, especially the content of Fe and Al, is required to be very low. With the increasing demand for high-purity quartz sand in these high-tech fields, the quality of quartz sand products is also required to be higher and higher. For example, quartz sand used for quartz crucibles for drawing of single crystal silicon rods is required to have an impurity content of less than 6 ppm. At present, the domestic technology for preparing quartz sand of 5N grade or above is not mature, and mainly relies on import from abroad. In addition to being subject to foreign technology, the cost is also too high. Therefore, it is an urgent need in the domestic quartz sand market to develop a low-cost technology for preparing high-purity quartz sand or even ultra-high-purity quartz sand.

[0003] Currently, the preparation of high-purity synthetic quartz sand mainly comes from the hydrolysis reaction of silicon-containing precursors, such as silicon tetrachloride or organosilane tetramethoxysilane, tetraethoxysilane, etc. Chinese patent CN1314608C discloses a method for synthesizing quartz glass using high-frequency plasma gas phase, which generates silicon dioxide particles by mixing oxygen and silicon tetrachloride gas and depositing them onto the target surface in the production furnace. The hydroxyl content of the quartz glass synthesized by this method is less than 5 ppm, the metal impurity content can reach below 1 ppm, but the chlorine ion content reaches 200 ppm, which can only be used for high-quality quartz pendulum plate and special optical material requirements, and cannot be used in the technical field of semiconductors. Chinese patent CN10862091B discloses a method for preparing high-purity quartz sand, which hydrolyzes a mixture of organosilane and chlorosilane compound under acidic or basic conditions to obtain a silicic acid solution, removes impurities from the silicic acid solution, and then dries the powder to obtain a high-purity quartz sand powder. The single alkali metal impurity content of the high-purity quartz sand synthesized by this method is less than 1 ppm, and the hydroxyl content is less than 10 ppm, but the product purity can only reach 99.999% (5N grade). According to the synthesis method, the main reason for the content of the synthesized quartz sand product not reaching 6N is the presence of chlorine impurities and unpurified organosilane. US patent application number US07485954 discloses a method for manufacturing high-purity synthetic quartz glass products, wherein the purity of the quartz sand product synthesized in Example 1 can reach 99.9999% (6N), and the hydroxyl content can reach below 10 ppm, but the crushed and sieved quartz sand product still needs to be purified with acid for the second time, and the process is relatively complex. SUMMARY

[0004] To solve the above problems, the present application provides a 6N grade large particle high-purity synthetic quartz sand and a preparation method thereof. The preparation method is simple, environmentally friendly, and low in energy consumption. The total amount of metal impurities in the prepared quartz sand is less than 100 ppb, the hydroxyl content is less than 10 ppm, and the purity is higher than 99.9999%.

[0005] To achieve the above purpose, the present application specifically adopts the following technical solutions:

[0006] A preparation method of 6N grade large particle quartz sand, comprising the following steps:

[0007] S1, adding high-purity water, electronic grade ammonia water, ultra-pure electronic grade C1-C2 alcohol and alcohol surfactant into a fluorine-lined reaction container;

[0008] S2, start stirring, add organosilicate into the reaction container dropwise, carry out primary hydrolysis at a first temperature, and then carry out deep hydrolysis at a second temperature; the second temperature is higher than the first temperature;

[0009] S3, separate silica from the reaction in step S2 to obtain quartz sand wet material; and calcine and crush the quartz sand wet material to obtain 6N grade large-particle quartz sand.

[0010] In the present application, the yield of large-particle quartz sand can be significantly improved by two-step hydrolysis of organosilicate at different temperatures and simultaneous addition of alcohol surfactant. The alcohol surfactant can promote the miscibility of inorganic phase and organic phase, and only contains C, H and Q elements. The surfactant remaining in the quartz sand wet material is decomposed into CO2 and H2O in the subsequent calcination process, and does not bring impurities into the quartz sand product.

[0011] Preferably, the alcohol surfactant comprises at least one of ethylene glycol, glycerol, polypropylene glycol, polyethylene glycol, diglycerol, acetylene glycol and polyether polyol.

[0012] Preferably, the mass ratio of the high-purity water, the electronic-grade ammonia water, the ultra-pure electronic-grade C1-C2 alcohol, the alcohol surfactant and the organosilicate is (1.0-2.2):(0.1-0.5):(0.1-0.3):(0.004-0.006):1.

[0013] Further preferably, the mass ratio of the high-purity water, the electronic-grade ammonia water, the ultra-pure electronic-grade C1-C2 alcohol, the alcohol surfactant and the organosilicate is (2.0-2.2):(0.3-0.5):(0.1-0.3):(0.004-0.006):1.

[0014] Preferably, the first temperature is -10-5℃, and the primary hydrolysis time is 8-12h.

[0015] Further preferably, the first temperature is -10--3℃, and the primary hydrolysis time is 8-12h.

[0016] Further preferably, the first temperature is -10--5℃, and the primary hydrolysis time is 8-12h.

[0017] Preferably, the second temperature is 30-70℃, and the deep hydrolysis time is 8-12h.

[0018] Further preferably, the second temperature is 50-70℃, and the deep hydrolysis time is 8-12h.

[0019] Preferably, the stirring speed in the primary hydrolysis in step S2 is 50-250 rpm; further preferably 90-110 rpm.

[0020] Preferably, the stirring speed in the deep hydrolysis in step S2 is 50-250 rpm; further preferably 90-110 rpm.

[0021] Preferably, the resistivity of the high-purity water at 25℃ is >18 MΩ·cm.

[0022] Preferably, the total amount of metal impurities in the electronic-grade ammonia water is <10 ppb.

[0023] Preferably, the calcination in step S3 refers to holding at 250-350℃ for 3.5-4.5 h, then holding at 630-730℃ for 2.5-3.5 h, and finally holding at 1300-1350℃ for 4-4.5 h.

[0024] Preferably, the organosilicate includes at least one of tetraethyl orthosilicate and tetramethyl orthosilicate.

[0025] The application also provides 6N-grade large-particle quartz sand prepared according to the preparation method of the 6N-grade large-particle quartz sand. The 6N-grade large-particle quartz sand has an Al content ≤20 ppb, a B content ≤15 ppb, a Ca content ≤25 ppb, an Fe content ≤10 ppb, a K content ≤10 ppb, a Na content ≤20 ppb, and no Gr, Cu, Li, Mg, Ni, Mn, and Ti detected; a hydroxyl content ≤10 ppm; and a particle size of 75-250 μm.

[0026] The application has the following beneficial effects: (1) In the application, large-particle quartz sand with a particle size meeting the requirements of GB / T32649-2016 is synthesized by a chemical synthesis method. The use of alcohol surfactants and hydrolysis of organosilicate at different temperatures in the synthesis process can significantly improve the yield of large-particle quartz sand, so that the yield of synthetic quartz sand reaches more than 90%. (2) The large-particle quartz sand prepared in the application has a purity higher than 99.9999%, a total amount of metal impurities lower than 100 ppb, a hydroxyl content lower than 10 ppm, and a particle size of 75-250 microns, which meets the use requirements of high-end industries such as single-crystal quartz crucible inner coating, quartz fiber, semiconductor ultra-high-purity quartz material, and quartz rod for optical fiber. (3) The method for preparing large-particle quartz sand in the application is simple and environmentally friendly, has a high molar yield, and low energy consumption. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described clearly and completely in the following embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, any equivalent transformation or replacement made by those skilled in the art without creative labor according to the following embodiments is within the protection scope of the present application.

[0028] The detection method of the quartz sand in the following embodiments is in accordance with the provisions in GB / T 32649-2016 “High-purity quartz sand for photovoltaic use”.

[0029] Embodiment 1

[0030] The present embodiment provides a preparation method of 6N grade large particle synthetic quartz sand, comprising the following steps:

[0031] S1. In a clean experimental environment, 40 kg of high-purity water (resistivity of 18.3 MΩ·cm), 7 kg of electronic grade ammonia water (total amount of metal impurities less than 10 ppb), 3 kg of ultra-pure electronic grade (USE) ethanol and 0.1 kg of glycerol were added into a reaction container made of polytetrafluoroethylene.

[0032] S2. Start stirring and control the stirring speed at 105 r / min, at the same time, control the temperature in the reaction container at -8 to -7℃, then add 18 kg of tetraethyl orthosilicate-28 (total amount of metal impurities less than 20 ppb) into the reaction container dropwise to synthesize large particle silicon dioxide by primary hydrolysis reaction, and the primary hydrolysis reaction time is 10 h. After the primary hydrolysis reaction is completed, the reaction container is heated to 60℃ to perform deep hydrolysis reaction to ensure that the alkoxyl groups are completely hydrolyzed, and the deep hydrolysis reaction time is 10 h. The main reaction equation involved in the reaction process is as follows:

[0033]

[0034] S3. After the deep hydrolysis reaction is completed, 15.4 kg of large particle quartz sand wet material is obtained by solid-liquid separation; the filtrate is purified by distillation and used for synthesizing quartz sand in the next batch of step S2. The large particle quartz sand wet material is placed in a high-temperature furnace, and the furnace temperature is first raised to 300℃ for 4 h to remove organic matter, then the temperature is raised to 680℃ for 3 h to remove carbon, and finally the temperature is raised to 1350℃ for 4 h to remove hydroxyl groups, to obtain 5.10 kg of blocky quartz sand crystal material. The blocky quartz sand crystal material is crushed without sieving, and 5.10 kg of large particle quartz sand product is directly obtained (based on the theoretical yield of silicon dioxide in step S2, the molar yield is 98.27%), the product particle size is 75-250 μm, the hydroxyl content is 7 ppm, the total amount of metal and non-metal elements is less than 100 ppb, and the metal element detection data in the product are shown in Table 1.

[0035] Table 1 Metal element detection results of quartz sand product of Example 1

[0036] Element Al B Ca Gr Cu Fe K Li Mg Na Ni Mn Ti Content (ppb) 15 12 20 0 0 7 3 0 0 12 0 0 0

[0037] Example 2

[0038] The present embodiment provides a preparation method of 6N grade large particle synthetic quartz sand, comprising the following steps:

[0039] S1, under a clean experimental environment, 32 kg of high-purity water (resistivity of 18.5 MΩ·cm), 7 kg of electronic grade ammonia water (total amount of metal impurities less than 10 ppb), 4 kg of ultra-pure electronic grade (USE) ethanol and 0.08 kg of diglycerol were added into a reaction container made of Teflon material.

[0040] S2, start stirring and control the stirring speed at 90 r / min, at the same time control the temperature in the reaction container at -6 to -5℃, then add 15 kg of tetraethyl orthosilicate-28 (total amount of metal impurities less than 20 ppb) into the reaction container dropwise to carry out primary hydrolysis reaction to synthesize large particle silicon dioxide, and the primary hydrolysis reaction time is 8 h. After the primary hydrolysis reaction is completed, the reaction container is heated to 70℃ to carry out deep hydrolysis reaction to ensure that the alkoxyl groups are completely hydrolyzed, and the deep hydrolysis reaction time is 8 h. The main reaction equation involved in the reaction process is the same as that of Example 1.

[0041] S3, after the deep hydrolysis reaction is completed, 12.9 kg of large particle quartz sand wet material is obtained by solid-liquid separation; the filtrate is purified by distillation and used for synthesizing quartz sand in the next batch of step S2. The large particle quartz sand wet material is placed in a high-temperature furnace, and the furnace temperature is first raised to 250℃ for 4.5 h to remove organic matter, then the temperature is raised to 730℃ for 2.5 h to remove carbon, and finally the temperature is raised to 1350℃ for 4 h to remove hydroxyl groups, thereby obtaining 4.27 kg of blocky quartz sand crystalline material. The blocky quartz sand crystalline material is crushed without sieving, and 4.27 kg of large particle quartz sand product (based on the theoretical yield of silicon dioxide in step S2, the molar yield is 98.61%) is directly obtained. The product particle size is 75-250 μm, the hydroxyl content is 5 ppm, the total amount of metal and non-metal elements is less than 100 ppb, and the metal element detection data of the product are shown in Table 2.

[0042] Table 2 Metal element detection results of quartz sand product of Example 2

[0043] Element Al B Ca Gr Cu Fe K Li Mg Na Ni Mn Ti Content (ppb) 18 10 22 0 0 5 8 0 0 18 0 0 0

[0044] Example 3

[0045] The present embodiment provides a preparation method of 6N grade large particle synthetic quartz sand, comprising the following steps:

[0046] S1, in a clean experimental environment, to the reaction container lined with fluorine material is added 40 kg of high purity water (resistivity of 18.3 MΩ·cm), 6 kg of electronic grade ammonia (total amount of metal impurities less than 10 ppb), 2 kg of ultra-pure electronic grade (USE) ethanol and 0.1 kg of polyethylene glycol.

[0047] S2, open the stirring, control the stirring speed is 110 r / min, while the temperature in the reaction container is controlled at-10~ -9 ℃, then 20 kg of tetraethyl orthosilicate-28 (total amount of metal impurities less than 20 ppb) is added to the reaction container, the primary hydrolysis reaction is carried out to synthesize large particle silica, the primary hydrolysis reaction time is 12 h. After the primary hydrolysis reaction is completed, the reaction container is heated to 50 ℃, and the depth hydrolysis reaction is carried out to ensure that the alkoxyl group is completely hydrolyzed, and the depth hydrolysis reaction time is 12 h. The main reaction equation involved in the reaction process is the same as that of example 1.

[0048] S3, after the depth hydrolysis reaction is completed, 17.1 kg of large particle quartz sand wet material is obtained by solid-liquid separation; the filtrate is purified by distillation and used for synthesizing quartz sand in the next batch of step S2. The large particle quartz sand wet material is put into a high temperature furnace, and the furnace temperature is first raised to 350 ℃ for 3.5 h to remove organic matter, then the temperature is raised to 630 ℃ for 3.5 h to remove carbon, and finally the temperature is raised to 1300 ℃ for 4.5 h to remove hydroxyl group, obtaining 5.7 kg of blocky quartz sand crystal material. The blocky quartz sand crystal material is crushed, without sieving, directly obtaining 5.7 kg of large particle quartz sand product (based on the theoretical yield of silica in step S2, the molar yield is 98.79%), the product particle size is 75~250 μm, the hydroxyl content is 8 ppm, the total amount of metal and non-metal elements is less than 100 ppb, and the metal element detection data in the product is shown in table 3.

[0049] Table 3 metal element detection results of quartz sand product in example 3

[0050] Element Al B Ca Gr Cu Fe K Li Mg Na Ni Mn Ti Content (ppb) 16 9 22 0 0 8 3 0 0 13 0 0 0

[0051] Example 4

[0052] A method for preparing 6N grade large particle synthetic quartz sand is provided in this example, comprising the following steps:

[0053] S1, in a clean experimental environment, to the reaction container lined with fluorine material is added 40 kg of high purity water (resistivity of 18.3 MΩ·cm), 6 kg of electronic grade ammonia (total amount of metal impurities less than 10 ppb), 2 kg of ultra-pure electronic grade (USE) ethanol and 0.1 kg of polyethylene glycol.

[0054] S2, start stirring and control the stirring speed at 90 r / min, and control the temperature in the reaction vessel at 0-5°C, then add 11 kg of tetramethyl orthosilicate (total amount of metal impurities less than 20 ppb) dropwise into the reaction vessel to perform a primary hydrolysis reaction to synthesize large-particle silica, and the primary hydrolysis reaction time is 8 h. After the primary hydrolysis reaction is completed, the reaction vessel is warmed to 50°C to perform a deep hydrolysis reaction to ensure complete hydrolysis of the alkoxy group, and the deep hydrolysis reaction time is 12 h. The main reaction equation involved in the reaction process is as follows:

[0055]

[0056] S3, after the deep hydrolysis reaction is completed, solid-liquid separation is performed to obtain 12.84 kg of quartz sand wet material; the filtrate is purified by distillation and used for synthesizing quartz sand in the next batch of step S2. The quartz sand wet material is placed in a high-temperature furnace, and the furnace temperature is first raised to 300°C for 4 h to remove organic matter, then raised to 680°C for 3 h to remove carbon, and finally raised to 1350°C for 4 h to remove hydroxyl groups, to obtain 4.28 kg of blocky quartz sand crystalline material. The blocky quartz sand crystalline material is crushed and sieved through a 200-mesh sieve to obtain 0.34 kg of quartz sand particles with a particle size of less than 75 μm, and at the same time, 3.94 kg of large-particle quartz sand product (based on the theoretical yield of silica in step S2, the molar yield is 90.78%) is obtained, the product particle size is 75-250 μm, the hydroxyl content is 8 ppm, and the total amount of metal and non-metal elements is less than 100 ppb, and the metal element detection data in the product are shown in Table 4.

[0057] Table 4 Metal element detection results of the quartz sand product of Example 4

[0058] Element Al B Ca Gr Cu Fe K Li Mg Na Ni Mn Ti Content (ppb) 15 9 20 0 0 8 4 0 0 15 0 0 0

[0059] Comparative Example 1

[0060] This comparative example provides a method for preparing high-purity quartz sand, which is basically the same as Example 3, except that:

[0061] No polyethylene glycol is added in step S1;

[0062] After the deep hydrolysis reaction in step S3 is completed, solid-liquid separation is performed to obtain 17.1 kg of large-particle quartz sand wet material; the filtrate is purified by distillation and used for synthesizing quartz sand in step S2 of the next batch. The large-particle quartz sand wet material is placed in a high-temperature furnace, and the furnace temperature is raised by programming to 350°C for 3.5 h to remove organic matter, then to 630°C for 3.5 h to remove carbon, and finally to 1300°C for 4.5 h to remove hydroxyl groups, to obtain 5.7 kg of blocky quartz sand crystalline material. The 5.7 kg of blocky quartz sand crystalline material is crushed and sieved through a 200-mesh sieve, containing 15 wt% (0.85 kg) of small-particle quartz sand product, to obtain 4.85 kg of large-particle quartz sand product (molar yield of 84.06% based on the theoretical yield of silicon dioxide in step S2), the product particle size is 75-250 microns, the hydroxyl content is 6 ppm, and the total amount of metal elements is less than 100 ppb. The detection data of metal and non-metal elements in the product are shown in Table 5.

[0063] Table 5 Detection results of metal elements in the quartz sand product of Comparative Example 1

[0064] Element Al B Ca Gr Cu Fe K Li Mg Na Ni Mn Ti Content (ppb) 17 8 21 0 0 9 5 0 0 15 0 0 0

[0065] Comparative Example 2

[0066] This comparative example provides a method for preparing high-purity quartz sand, which is basically the same as Example 2, except that:

[0067] In step S2, the temperature in the reaction container is controlled to 6-10°C, and then 15 kg of tetraethyl orthosilicate-28 (total amount of metal impurities less than 20 ppb) is added dropwise into the reaction container;

[0068] After the deep hydrolysis reaction in step S3 is completed, solid-liquid separation is performed to obtain 12.9 kg of large-particle quartz sand wet material; the filtrate is purified by distillation and used for synthesizing quartz sand in step S2 of the next batch. The large-particle quartz sand wet material is placed in a high-temperature furnace, and the furnace temperature is raised by programming to 250°C for 4.5 h to remove organic matter, then to 730°C for 2.5 h to remove carbon, and finally to 1350°C for 4 h to remove hydroxyl groups, to obtain 4.26 kg of blocky quartz sand crystalline material. The 4.26 kg of blocky quartz sand crystalline material is crushed and sieved through a 200-mesh sieve, containing 1.2 kg (28.2 wt%) of small-particle (particle size < 75 μm) quartz sand product, to obtain 3.06 kg of large-particle quartz sand product (molar yield of 70.74% based on the theoretical yield of silicon dioxide in step S2), the product particle size is 75-250 microns, the hydroxyl content is 6 ppm, and the total amount of metal elements is less than 100 ppb. The detection data of metal and non-metal elements in the product are shown in Table 6.

[0069] Table 6 Detection results of metal elements in the quartz sand product of Comparative Example 2

[0070] Element Al B Ca Gr Cu Fe K Li Mg Na Ni Mn Ti Content (ppb) 16 8 23 0 0 8 5 0 0 19 0 0 0

[0071] Comparative Example 3

[0072] This comparative example provides a method for preparing high purity quartz sand, which is substantially the same as Example 2, except that:

[0073] In step S2, the temperature in the reaction vessel is controlled to be -15 to -11°C, and then 15 kg of tetraethyl orthosilicate (-28, total amount of metal impurities less than 20 ppb) is added dropwise into the reaction vessel; a primary hydrolysis reaction is performed to synthesize large particle silica, and the primary hydrolysis reaction time is 12 h. After the primary hydrolysis reaction is completed, the reaction vessel is warmed to 70°C, and a deep hydrolysis reaction is performed to ensure complete hydrolysis of the alkoxy group, and the deep hydrolysis reaction time is 12 h.

[0074] After the deep hydrolysis reaction in step S3 is completed, 12.8 kg of large particle quartz sand wet material is obtained by solid-liquid separation; the filtrate is purified by distillation and used for synthesizing quartz sand in step S2 of the next batch. The large particle quartz sand wet material is placed in a high temperature furnace, and the furnace temperature is first raised to 250°C for 4.5 h to remove organic matter, then raised to 730°C for 2.5 h to remove carbon, and finally raised to 1350°C for 4 h to remove hydroxyl groups, obtaining 4.27 kg of blocky quartz sand crystalline material. After crushing the 4.27 kg of blocky quartz sand crystalline material and sieving it through a 200 mesh sieve, 45 wt% (1.92 kg) of small particle (particle size <75 μm) quartz sand product and 2.35 kg of large particle quartz sand product (molar yield of 54.32% based on the theoretical yield of silica in step S2) are obtained, the product particle size is 75-250 microns, the hydroxyl content is 7 ppm, and the total amount of metal elements is less than 100 ppb. The metal and non-metal element detection data in the product are shown in Table 7.

[0075] Table 7 Metal element detection results of quartz sand product in Comparative Example 3

[0076] Element Al B Ca Gr Cu Fe K Li Mg Na Ni Mn Ti Content (ppb) Element Ca Cu Fe Li Mg Na Ni Mn Ti Content (ppb) 15 9 21 0 0 7 6 0 0 17 0 0 0

[0077] According to the product yield of Comparative Example 1 and Example 3, it can be found that the alcohol surfactant in the technical scheme of the present application helps the growth of the silica crystal nucleus, and larger quartz sand particles can be obtained. According to the product yield of Comparative Example 2 and Comparative Example 3 and Example 2, it can be found that the temperature of the primary hydrolysis of the organosilicate in step S2 can significantly affect the particle size of the quartz sand, and too high a temperature (more than 5℃) or too low a temperature (less than -10℃) is not conducive to the growth of the silica crystal nucleus. According to the product yield of Examples 1-4, it can be found that when the primary hydrolysis temperature is -10 to -3℃, the yield of 6N large-particle quartz sand can reach more than 98.0%; when the primary hydrolysis temperature is -10 to -5℃, the yield of 6N large-particle quartz sand can reach more than 98.5%. It can be seen that the lack of alcohol surfactant or inappropriate hydrolysis temperature of the organosilicate will result in the generation of a part of quartz sand with a particle size of less than 75 microns, which seriously affects the yield of quartz sand with a particle size of 75-250 microns, and the quartz sand with a particle size of less than 75 microns cannot be sold as by-products (equivalent to a large amount of solid waste), thereby significantly increasing the production cost of 6N quartz sand.

[0078] The above only describes the preferred embodiments of the present application and is not used to limit the protection scope of the present application. The present application can have various changes and variations for any skilled person in the art. Any simple equivalent changes and modifications made according to the content of the present application and the specification should be included in the protection scope of the present application.

Claims

1. A method for producing 6N grade large particle quartz sand, characterized by, The method comprises the following steps: S1, adding high-purity water, electronic-grade ammonia, ultra-pure electronic-grade C1-C2 alcohol and alcohol surfactant into a fluorine-lined reaction container; S2, starting stirring, and adding organosilicon ester into the reaction container, performing primary hydrolysis at-10--5℃ for 8-12h, and then performing deep hydrolysis at 30-70℃ for 8-12h; S3, separating silica from the reaction after step S2, obtaining quartz sand wet material; calcining and crushing the quartz sand wet material to obtain 6N large-particle quartz sand; the calcining refers to keeping the temperature at 250-350℃ for 3.5-4.5h, then keeping the temperature at 630-730℃ for 2.5-3.5h, and finally keeping the temperature at 1300-1350℃ for 4-4.5h; The mass ratio of the high-purity water, the electronic-grade ammonia, the ultra-pure electronic-grade C1-C2 alcohol, the alcohol surfactant and the organosilicon ester is (1.0-2.2):(0.1-0.5):(0.1-0.3):(0.004-0.006):

1.

2. The method of producing 6N grade large particle quartz sand according to claim 1, characterized by, The alcohol surfactant comprises at least one of ethylene glycol, glycerol, polypropylene glycol, polyethylene glycol, diglycerol, acetylene glycol and polyether polyol.

3. The method of producing 6N grade large particle quartz sand according to claim 1, characterized by, The mass ratio of the high-purity water, the electronic-grade ammonia, the ultra-pure electronic-grade C1-C2 alcohol, the alcohol surfactant and the organosilicon ester is (2.0-2.2):(0.3-0.5):(0.1-0.3):(0.004-0.006):

1.

4. The method of producing 6N grade large particle quartz sand according to claim 1, characterized by, The high-purity water has an electrical resistivity of >18MΩ·cm at 25℃; or / and the total amount of metal impurities in the electronic-grade ammonia is <10ppb.

5. The method of producing 6N grade large particle quartz sand according to claim 1, characterized by, The organosilicon ester comprises at least one of tetraethyl orthosilicate and tetramethyl orthosilicate.

6. The 6N large-particle quartz sand prepared by the preparation method in any one of claims 1-5.

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