Method for preparing high-purity synthetic quartz using silica mud

Abstract

The application discloses a method for preparing high-purity synthetic quartz by using silicon mud, which comprises the following steps: washing the silicon mud with water, adding an alkaline catalyst into the washed silicon mud to mix and react with water, and obtaining a mixed solution; performing nano filtration on the mixed solution obtained in the step to remove solid particles of silicon carbide and metal oxides with large sizes, and at this time, the composition of the filtrate is small-particle-size nano silicon dioxide and other impurity ions. In the application, the silicon mud is pretreated without using the acid washing method when the silicon mud is treated, so that no waste acid and waste water are discharged in the preparation process, the process is simple, the application is friendly to the environment, the impurities in the silicon mud are separated by using a multi-stage filtering membrane group physical separation method, the separation cost is low, the recycling of the metal oxides and the silicon carbide is not affected, the resource utilization is more sufficient and reasonable, and the high-purity synthetic quartz does not contain silicon carbide inclusions and has higher purity.

Description

Technical Field

[0001] This invention relates to the field of quartz synthesis technology, specifically a method for preparing high-purity synthetic quartz using silica mud. Background Technology

[0002] The process of crystalline silicon slicing generates a large amount of cutting waste liquid, the main components of which are high-purity silicon, silicon carbide, metal oxides and other organic matter. After washing and dehydration, it forms silicon sludge. The main components of silicon sludge are about 90% high-purity silicon, less than 1% metal oxides, and the rest is silicon carbide. The solid particle size is usually between several hundred nanometers and tens of micrometers. Currently, the silicon sludge is recycled and reused by high-temperature melting to prepare metallic silicon.

[0003] In existing technologies, such as the Chinese patent CN202110866870.7, "A Method for Preparing High-Purity Quartz Sand Using Ultrafine Silica Powder," the main technical route involves washing and acid-washing photovoltaic wafer silica mud with water, then reacting it with an alkaline solution to generate silica sol. The silica sol is then further purified using an ion exchange method, followed by pH adjustment to form a gel. Finally, granulation and calcination processes remove water and hydroxyl groups, and close the pores, thus producing high-purity, low-cost silica sand.

[0004] However, the existing methods have the following shortcomings in practical applications: 1. Removing metal oxides by acid washing is costly due to the high cost of acid washing and waste acid treatment, and larger metal oxides are difficult to clean completely; 2. Silicon carbide is chemically stable and cannot be removed by acid washing. Furthermore, silicon carbide is not removed during pretreatment and synthesis. After the sol mixed with silicon carbide is directly gelled and granulated, silicon carbide remains between the quartz particles, and the resulting high-purity quartz is a mixture of silicon carbide and silicon oxide, which cannot meet the application requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing high-purity synthetic quartz using silica sludge, in order to solve the problems mentioned in the background art, such as the high cost of acid washing and waste acid treatment, the difficulty in cleaning larger metal oxides, the inability to remove silicon carbide by acid washing due to its stable chemical properties, and the lack of silicon carbide removal treatment during pretreatment and synthesis. Furthermore, the direct gelation and granulation of sol mixed with silicon carbide leaves silicon carbide residues between quartz particles, resulting in high-purity quartz that is a mixture of silicon carbide and silicon oxide, which cannot meet the requirements of use.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing high-purity synthetic quartz using silica mud, wherein the high-purity synthetic quartz is made from the following raw materials in parts by weight: 10-30 parts by weight of silica mud, 100-150 parts by weight of water, 0.01-1 parts by weight of alkaline catalyst and 30-50 parts by weight of cation exchange resin.

[0007] The method for preparing the high-purity synthetic quartz includes the following steps:

[0008] S1. Wash the silica mud with water, add an alkaline catalyst to the washed silica mud and mix it with water to obtain a mixed solution.

[0009] S2. The mixed solution obtained in the previous step is filtered through nanofiltration to remove large silicon carbide and metal oxide solid particles. At this time, the filtrate consists of small-diameter nano-silica and other impurity ions.

[0010] S3. Pass the mixture obtained in the previous step through an ion exchange resin to remove metal impurity cations and obtain high-purity nano silica sol.

[0011] S4. The obtained high-purity nano-silica sol is dried and dehydrated, and then sintered at high temperature to densify it, thereby obtaining high-purity synthetic quartz.

[0012] Preferably, in step S1, the addition of an alkaline catalyst to the washed silica mud and its reaction with water includes the following steps:

[0013] S11. Accurately weigh the silica mud, wash it thoroughly with water, mix it with water, and add it to the mixing tank for mixing. The internal temperature of the mixing tank is 90℃, and the stirring speed is 200r / min.

[0014] S12. Add an alkaline catalyst dropwise to the mixture in the stirred tank and maintain the pH value at 8-10;

[0015] S13. After the silicon material has fully reacted, a mixed solution of silica sol, metal oxide, and silicon carbide is obtained.

[0016] Preferably, in step S1, the alkaline catalyst is one or more combinations of inorganic bases such as ammonia, sodium hydroxide, and potassium hydroxide, and organic bases such as ethylenediamine, quaternary ammonium base, and nicotine.

[0017] Preferably, in step S1, the small-particle-size silica sol has a particle size of less than 20 nm and a sol solid content of 1%–15%.

[0018] Preferably, in step S2, the pore size of the filter membrane used for nanofiltration is 50nm-200nm.

[0019] Preferably, in step S3, the ion exchange resin is an H-type cation exchange resin.

[0020] Preferably, in step S4, the densification of the obtained high-purity nano-silica sol by drying and dehydration followed by high-temperature sintering includes the following steps:

[0021] S41. The high-purity nano silica sol is thoroughly dried to remove moisture and organic matter, resulting in dry silica.

[0022] S42. The silicon dioxide obtained in S41 is heated to 1100℃ at a rate of 1℃ / min and held for 20h for high-temperature sintering densification treatment.

[0023] S43. Cool the synthetic quartz particles that have been densified by high-temperature sintering and collect them.

[0024] Preferably, in step S4, the drying method is one of direct drying, freeze drying, vacuum refrigeration, and microwave drying.

[0025] Preferably, in step S4, the calcination is either atmospheric pressure calcination or vacuum calcination.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] In this method, there is no need to pretreat the silica sludge with acid washing, so there is no waste acid or wastewater discharge during the preparation process. The process is simple and environmentally friendly. Furthermore, the impurities in the silica sludge are separated by physical removal through a multi-stage filtration membrane module, which has low separation cost and does not affect the recycling of metal oxides and silicon carbide. Resource utilization is more efficient and reasonable. The target high-purity synthetic quartz is free of silicon carbide inclusions and has higher purity. Attached Figure Description

[0028] Figure 1 This is a flowchart of a method for preparing high-purity synthetic quartz using silica mud according to the present invention;

[0029] Figure 2 This is a statistical chart of quartz impurity content in a method for preparing high-purity synthetic quartz using silica mud according to the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1: This example provides a method for preparing high-purity synthetic quartz using silica mud. The high-purity synthetic quartz is made from the following raw materials in parts by weight: 20 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst and 40 parts by weight of cation exchange resin.

[0032] The preparation method of high-purity synthetic quartz includes the following steps:

[0033] Ⅰ. Wash the silica mud with water, add an alkaline catalyst to the washed silica mud and mix it with water to obtain a mixed solution;

[0034] Specifically, the reaction of adding an alkaline catalyst to the washed silica sludge and mixing it with water includes the following steps: accurately weighing the silica sludge, thoroughly washing it with water, mixing it with water, and adding it to a stirred tank for stirring and mixing. The internal temperature of the stirred tank is 90℃, and the stirring speed is 200 r / min. An alkaline catalyst is added dropwise to the mixture in the stirred tank, maintaining the pH value at 8-10. After the silica material has fully reacted, a mixed solution of silica sol, metal oxide, and silicon carbide is obtained. The silica sol particle size is measured to be 17 nm, and the sol solid content is 15%.

[0035] Among them, the alkaline catalyst is an inorganic base: ammonia, sodium hydroxide, potassium hydroxide and an organic base: ethylenediamine, quaternary ammonium base, nicotine or one or more combinations thereof;

[0036] II. After diluting the mixed solution obtained in the previous step at a ratio of 1:5, filter it thoroughly through a nanofilter to remove larger silicon carbide and metal oxide solid particles. At this time, the filtrate components are small-diameter nano-silica and other impurity ions. After filtering the mixed solution, silicon carbide and metal oxide particles can be fully removed.

[0037] The filter membrane module is a multi-stage filter with pore sizes of 200nm, 100nm, and 50nm, and a filtration pressure of 10kPa.

[0038] III. The mixture obtained in the previous step is passed through an ion exchange resin to remove metal impurity cations, resulting in high-purity nano silica sol.

[0039] The ion exchange resin is an H-type cation exchange resin.

[0040] IV. The obtained high-purity nano-silica sol is dried and dehydrated, then sintered at high temperature to densify it, thus obtaining high-purity synthetic quartz;

[0041] Specifically, the high-purity nano-silica sol obtained is dried, dehydrated, and then sintered at high temperature to densify it, which includes the following steps: the high-purity nano-silica sol is thoroughly dried to remove moisture and organic matter, resulting in dried silica particles; the dried silica particles are heated to 1100℃ at a rate of 1℃ / min and held at that temperature for 20 hours for high-temperature sintering and densification; the synthetic quartz particles that have undergone high-temperature sintering and densification are cooled and collected. After testing, the impurity content is 42ppm, and the silica content is >99.995%, reaching the 4N5 grade high-purity quartz standard.

[0042] The drying method can be one of direct drying, freeze drying, vacuum drying, or microwave drying. Alternatively, the sol can be gelled by adjusting the pH and temperature of the sol, and then the gel can be dried using the above-mentioned methods. The calcination is carried out using vacuum calcination.

[0043] Example 2: This example provides a method for preparing high-purity synthetic quartz using silica mud. The high-purity synthetic quartz is made from the following raw materials in parts by weight: 10 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst and 40 parts by weight of cation exchange resin.

[0044] The preparation method of high-purity synthetic quartz includes the following steps:

[0045] Ⅰ. Wash the silica mud with water, add an alkaline catalyst to the washed silica mud and mix it with water to obtain a mixed solution;

[0046] Specifically, the reaction of adding an alkaline catalyst to the washed silica sludge and mixing it with water includes the following steps: accurately weighing the silica sludge, thoroughly washing it with water, mixing it with water, and adding it to a stirred tank for stirring and mixing. The internal temperature of the stirred tank is 90℃, and the stirring speed is 200 r / min. An alkaline catalyst is added dropwise to the mixture in the stirred tank, maintaining the pH value at 8-10. After the silica material has fully reacted, a mixed solution of silica sol, metal oxide, and silicon carbide is obtained. The silica sol particle size is measured to be 23 nm, and the sol solid content is 15%.

[0047] Among them, the alkaline catalyst is an inorganic base: ammonia, sodium hydroxide, potassium hydroxide and an organic base: ethylenediamine, quaternary ammonium base, nicotine or one or more combinations thereof;

[0048] II. After diluting the mixed solution obtained in the previous step at a ratio of 1:5, filter it thoroughly through a nanofilter to remove larger silicon carbide and metal oxide solid particles. At this time, the filtrate components are small-diameter nano-silica and other impurity ions. After filtering the mixed solution, silicon carbide and metal oxide particles can be fully removed.

[0049] The filter membrane module is a multi-stage filter with pore sizes of 200nm, 100nm, and 50nm, and a filtration pressure of 10kPa.

[0050] III. The mixture obtained in the previous step is passed through an ion exchange resin to remove metal impurity cations, resulting in high-purity nano silica sol.

[0051] The ion exchange resin is an H-type cation exchange resin.

[0052] IV. The obtained high-purity nano-silica sol is dried and dehydrated, then sintered at high temperature to densify it, thus obtaining high-purity synthetic quartz;

[0053] Specifically, the high-purity nano-silica sol obtained is dried, dehydrated, and then sintered at high temperature to densify it, which includes the following steps: the high-purity nano-silica sol is thoroughly dried to remove moisture and organic matter, resulting in dried silica particles; the dried silica particles are heated to 1100℃ at a rate of 1℃ / min and held at that temperature for 20 hours for high-temperature sintering and densification; the synthetic quartz particles that have undergone high-temperature sintering and densification are cooled and collected. After testing, the impurity content is 68ppm, and the silica content is >99.99%, reaching the 4N grade high-purity quartz standard.

[0054] The drying method can be one of direct drying, freeze drying, vacuum drying, or microwave drying. Alternatively, the sol can be gelled by adjusting the pH and temperature of the sol, and then the gel can be dried using the above-mentioned methods. The calcination is carried out using vacuum calcination.

[0055] Example 3: This example provides a method for preparing high-purity synthetic quartz using silica mud. The high-purity synthetic quartz is made from the following raw materials in parts by weight: 30 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst, and 40 parts by weight of cation exchange resin.

[0056] The preparation method of high-purity synthetic quartz includes the following steps:

[0057] Ⅰ. Wash the silica mud with water, add an alkaline catalyst to the washed silica mud and mix it with water to obtain a mixed solution;

[0058] Specifically, the reaction of adding an alkaline catalyst to the washed silica sludge and mixing it with water includes the following steps: accurately weighing the silica sludge, thoroughly washing it with water, mixing it with water, and adding it to a stirred tank for stirring and mixing. The internal temperature of the stirred tank is 90℃, and the stirring speed is 200 r / min. An alkaline catalyst is added dropwise to the mixture in the stirred tank, maintaining the pH value at 8-10. After the silica material has fully reacted, a mixed solution of silica sol, metal oxide, and silicon carbide is obtained. The silica sol particle size is measured to be 14 nm, and the sol solid content is 15%.

[0059] Among them, the alkaline catalyst is an inorganic base: ammonia, sodium hydroxide, potassium hydroxide and an organic base: ethylenediamine, quaternary ammonium base, nicotine or one or more combinations thereof;

[0060] II. After diluting the mixed solution obtained in the previous step at a ratio of 1:5, filter it thoroughly through a nanofilter to remove larger silicon carbide and metal oxide solid particles. At this time, the filtrate components are small-diameter nano-silica and other impurity ions. After filtering the mixed solution, silicon carbide and metal oxide particles can be fully removed.

[0061] The filter membrane module is a multi-stage filter with pore sizes of 200nm, 100nm, and 50nm, and a filtration pressure of 10kPa.

[0062] III. The mixture obtained in the previous step is passed through an ion exchange resin to remove metal impurity cations, resulting in high-purity nano silica sol.

[0063] The ion exchange resin is an H-type cation exchange resin.

[0064] IV. The obtained high-purity nano-silica sol is dried and dehydrated, then sintered at high temperature to densify it, thus obtaining high-purity synthetic quartz;

[0065] Specifically, the high-purity nano-silica sol obtained is dried, dehydrated, and then sintered at high temperature to densify it, which includes the following steps: the high-purity nano-silica sol is thoroughly dried to remove moisture and organic matter, resulting in dried silica particles; the dried silica particles are heated to 1100℃ at a rate of 1℃ / min and held at that temperature for 20 hours for high-temperature sintering and densification; the synthetic quartz particles that have undergone high-temperature sintering and densification are cooled and collected. After testing, the impurity content is 39ppm, and the silica content is >99.995%, reaching the 4N5 grade high-purity quartz standard.

[0066] The drying method can be one of direct drying, freeze drying, vacuum drying, or microwave drying. Alternatively, the sol can be gelled by adjusting the pH and temperature of the sol, and then the gel can be dried using the above-mentioned methods. The calcination is carried out using vacuum calcination.

[0067] Example 4: This example provides a method for preparing high-purity synthetic quartz using silica mud. The high-purity synthetic quartz is made from the following raw materials in parts by weight: 20 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst and 40 parts by weight of cation exchange resin.

[0068] The preparation method of high-purity synthetic quartz includes the following steps:

[0069] Ⅰ. Wash the silica mud with water, add an alkaline catalyst to the washed silica mud and mix it with water to obtain a mixed solution;

[0070] Specifically, the reaction of adding an alkaline catalyst to the washed silica sludge and mixing it with water includes the following steps: accurately weighing the silica sludge, thoroughly washing it with water, mixing it with water, and adding it to a stirred tank for stirring and mixing. The internal temperature of the stirred tank is 90℃, and the stirring speed is 200 r / min. An alkaline catalyst is added dropwise to the mixture in the stirred tank, maintaining the pH value at 8-10. After the silica material has fully reacted, a mixed solution of silica sol, metal oxide, and silicon carbide is obtained. The silica sol particle size is measured to be 17 nm, and the sol solid content is 15%.

[0071] Among them, the alkaline catalyst is an inorganic base: ammonia, sodium hydroxide, potassium hydroxide and an organic base: ethylenediamine, quaternary ammonium base, nicotine or one or more combinations thereof;

[0072] II. After diluting the mixed solution obtained in the previous step at a ratio of 1:5, filter it thoroughly through a nanofilter to remove larger silicon carbide and metal oxide solid particles. At this time, the filtrate components are small-diameter nano-silica and other impurity ions. After filtering the mixed solution, silicon carbide and metal oxide particles can be fully removed.

[0073] The filter membrane module is a multi-stage filter with pore sizes of 100nm, 50nm, and 25nm, and a filtration pressure of 10kPa.

[0074] III. The mixture obtained in the previous step is passed through an ion exchange resin to remove metal impurity cations, resulting in high-purity nano silica sol.

[0075] The ion exchange resin is an H-type cation exchange resin.

[0076] IV. The obtained high-purity nano-silica sol is dried and dehydrated, then sintered at high temperature to densify it, thus obtaining high-purity synthetic quartz;

[0077] Specifically, the high-purity nano-silica sol obtained is dried, dehydrated, and then sintered at high temperature to densify it, which includes the following steps: the high-purity nano-silica sol is thoroughly dried to remove moisture and organic matter, resulting in dried silica particles; the dried silica particles are heated to 1100℃ at a rate of 1℃ / min and held at that temperature for 20 hours for high-temperature sintering and densification; the synthetic quartz particles that have undergone high-temperature sintering and densification are cooled and collected. After testing, the impurity content is 41ppm, and the silica content is >99.995%, reaching the 4N5 grade high-purity quartz standard.

[0078] The drying method can be one of direct drying, freeze drying, vacuum drying, or microwave drying. Alternatively, the sol can be gelled by adjusting the pH and temperature of the sol, and then the gel can be dried using the above-mentioned methods. The calcination is carried out using vacuum calcination.

[0079] Example 5: This example provides a method for preparing high-purity synthetic quartz using silica mud. The high-purity synthetic quartz is made from the following raw materials in parts by weight: 20 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst, and 40 parts by weight of cation exchange resin.

[0080] The preparation method of high-purity synthetic quartz includes the following steps:

[0081] Ⅰ. Wash the silica mud with water, add an alkaline catalyst to the washed silica mud and mix it with water to obtain a mixed solution;

[0082] Specifically, the reaction of adding an alkaline catalyst to the washed silica sludge and mixing it with water includes the following steps: accurately weighing the silica sludge, thoroughly washing it with water, mixing it with water, and adding it to a stirred tank for stirring and mixing. The internal temperature of the stirred tank is 90℃, and the stirring speed is 200 r / min. An alkaline catalyst is added dropwise to the mixture in the stirred tank, maintaining the pH value at 8-10. After the silica material has fully reacted, a mixed solution of silica sol, metal oxide, and silicon carbide is obtained. The silica sol particle size is measured to be 17 nm, and the sol solid content is 15%.

[0083] Among them, the alkaline catalyst is an inorganic base: ammonia, sodium hydroxide, potassium hydroxide and an organic base: ethylenediamine, quaternary ammonium base, nicotine or one or more combinations thereof;

[0084] II. After diluting the mixed solution obtained in the previous step at a ratio of 1:5, filter it thoroughly through a nanofilter to remove larger silicon carbide and metal oxide solid particles. At this time, the filtrate components are small-diameter nano-silica and other impurity ions. After filtering the mixed solution, silicon carbide and metal oxide particles can be fully removed.

[0085] The filter module has been changed to a single filter membrane with a pore size of 200nm and a filtration pressure of 10kPa.

[0086] III. The mixture obtained in the previous step is passed through an ion exchange resin to remove metal impurity cations, resulting in high-purity nano silica sol.

[0087] The ion exchange resin is an H-type cation exchange resin.

[0088] IV. The obtained high-purity nano-silica sol is dried and dehydrated, then sintered at high temperature to densify it, thus obtaining high-purity synthetic quartz;

[0089] Specifically, the high-purity nano-silica sol obtained is dried, dehydrated, and then sintered at high temperature to densify it, which includes the following steps: the high-purity nano-silica sol is thoroughly dried to remove moisture and organic matter, resulting in dried silica particles; the dried silica particles are heated to 1100℃ at a rate of 1℃ / min and held at that temperature for 20 hours for high-temperature sintering and densification; the synthetic quartz particles that have undergone high-temperature sintering and densification are cooled and collected. After testing, the impurity content is 108ppm, and the silica content is <99.99%, which does not meet the 4N grade high-purity quartz standard.

[0090] The drying method can be one of direct drying, freeze drying, vacuum drying, or microwave drying. Alternatively, the sol can be gelled by adjusting the pH and temperature of the sol, and then the gel can be dried using the above-mentioned methods. The calcination is carried out using vacuum calcination.

[0091] The high-purity synthetic quartz prepared by Examples 1-4 and Comparative Example 1 were respectively designated as Experimental Examples 1-4 and Comparative Group 1; experiments were conducted and relevant data were recorded in Table 1.

[0092]

[0093] As shown in Table 1, compared with the comparative examples, the high-purity synthetic quartz in Examples 1, 3, and 4 has a lower content of quartz impurities, no silicon carbide inclusions in the target high-purity synthetic quartz, and higher purity of silicon dioxide content, all reaching the 4N5 grade high-purity quartz standard. There is no need to use acid washing to pre-treat the silica sludge, no waste acid or wastewater discharge, the process is simple and environmentally friendly, and the separation is carried out by physical removal using multi-stage filtration membrane modules, resulting in low separation cost and no impact on the recycling of metal oxides and silicon carbide, making resource utilization more efficient and reasonable.

[0094] In this method, after washing the silica mud, it reacts with water under the action of an alkaline catalyst. By controlling a high material-to-water ratio and reaction temperature, the silica powder can react at a relatively fast speed to produce nano-silica particles. Since there is no parent nucleus in the mixture, the newly generated nanoparticles are difficult to aggregate and grow, which can achieve the purpose of controlling the generation of small-particle-size silica sol. There is no need to use acid washing to pre-treat the silica mud, and there is no waste acid or wastewater discharge. The process is simple and environmentally friendly. Furthermore, the impurities in the silica mud are separated by a multi-stage filtration membrane group for sequential physical removal, which has low separation cost and does not affect the recycling of metal oxides and silicon carbide. Resource utilization is more efficient and reasonable. The target high-purity synthetic quartz is free of silicon carbide inclusions and has higher purity.

[0095] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-purity synthetic quartz using silica mud, characterized in that: The high-purity synthetic quartz is made from the following raw materials in parts by weight: 10-30 parts by weight of silica mud, 100-150 parts by weight of water, 0.01-1 parts by weight of alkaline catalyst and 30-50 parts by weight of cation exchange resin. The method for preparing the high-purity synthetic quartz includes the following steps: S1. Wash the silica mud with water, add an alkaline catalyst to the washed silica mud and mix it with water to obtain a mixed solution. The small-diameter silica sol particles in the mixed solution are less than 20 nm in size, the solid content of the sol is 1%-15%, and the alkaline catalyst is one or a combination of inorganic bases: ammonia, sodium hydroxide, potassium hydroxide and organic bases: ethylenediamine, quaternary ammonium base, nicotine. S2. After diluting the mixed solution obtained in the previous step at a ratio of 1:5, the solution is thoroughly filtered through a nanofilter to remove larger silicon carbide and metal oxide solid particles. At this time, the filtrate consists of small-diameter nano-silica and other impurity ions. The nanofilter is a multi-stage filtration membrane group with pore sizes of 200nm, 100nm and 50nm respectively, and a filtration pressure of 10kpa. S3. Pass the mixture obtained in the previous step through an ion exchange resin to remove metal impurity cations and obtain high-purity nano silica sol. S4. The obtained high-purity nano-silica sol is dried and dehydrated, and then sintered at high temperature to densify it, thereby obtaining high-purity synthetic quartz.

2. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, In step S1, the process of adding an alkaline catalyst to the washed silica mud and mixing it with water includes the following steps: S11. Accurately weigh the silica mud, wash it thoroughly with water, mix it with water, and add it to the mixing tank for mixing. The internal temperature of the mixing tank is 90℃, and the stirring speed is 200r / min. S12. Add an alkaline catalyst dropwise to the mixture in the stirred tank and maintain the pH value at 8-10; S13. After the silicon material has fully reacted, a mixed solution of silica sol, metal oxide, and silicon carbide is obtained.

3. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, High-purity synthetic quartz is made from the following raw materials in parts by weight: 20 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst and 40 parts by weight of cation exchange resin.

4. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, High-purity synthetic quartz is made from the following raw materials in parts by weight: 10 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst and 40 parts by weight of cation exchange resin.

5. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, High-purity synthetic quartz is made from the following raw materials in parts by weight: 30 parts by weight of silica mud, 100 parts by weight of water, 0.1 parts by weight of alkaline catalyst and 40 parts by weight of cation exchange resin.

6. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, In step S3, the ion exchange resin is an H-type cation exchange resin.

7. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, In step S4, the densification of the obtained high-purity nano-silica sol by drying and dehydration followed by high-temperature sintering includes the following steps: S41. The high-purity nano silica sol is thoroughly dried to remove moisture and organic matter, resulting in dry silica. S42. The silicon dioxide obtained in S41 is heated to 1100℃ at a rate of 1℃ / min and held for 20h for high-temperature sintering densification treatment. S43. Cool the synthetic quartz particles that have been densified by high-temperature sintering and collect them.

8. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, In step S4, the drying method is one of direct drying, freeze drying, vacuum refrigeration, and microwave drying.

9. The method for preparing high-purity synthetic quartz using silica mud according to claim 1, characterized in that, In step S4, the calcination is either atmospheric pressure calcination or vacuum calcination.

Images