Method for determining silicon dioxide in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometer

Abstract

The invention relates to a method for determining silicon dioxide in quartz glass based on a high-temperature melting reaction-inductively coupled plasma atomic emission spectrometer. The method comprises the following steps: crushing and grinding a sample into powder; adding a strong alkali flux into the obtained powdery sample, and uniformly mixing to obtain a mixture; melting the mixture at high temperature; leaching reactants with hot water and fixing the volume; drawing a silicon element concentration-spectral line emission intensity standard curve; testing the content of silicon in the sample solution; and calculating the content of silicon dioxide according to the measured content of silicon. The method comprises the following steps: adding a strong alkali solvent into a powdery sample obtained by grinding the sample, carrying out a high-temperature melting reaction, heating water to dissolve a reactant, and determining the content of silicon in the solution by adopting an inductively coupled plasma atomic emission spectrometer, so as to calculate the content of silicon dioxide in the quartz glass sample.

Description

Technical Field

[0001] This invention belongs to the field of high-purity quartz glass detection technology, specifically relating to a method for determining silicon dioxide in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry. Background Technology

[0002] Quartz glass is a special industrial technical glass containing only silicon dioxide as its single component. Its main component is high-purity silicon dioxide (SiO2), typically with a purity of over 99.9%, containing little or no other elemental impurities or gas-liquid inclusions (at the ppm or even ppb level). Due to its unique closely packed silicon-oxygen tetrahedral covalent bond structure, quartz glass possesses a series of excellent properties, including high temperature resistance, chemical resistance (except for hydrofluoric acid and hot phosphoric acid), radiation resistance, thermal shock resistance, low coefficient of thermal expansion, good electrical insulation, and high full-spectrum optical transmittance. It is widely used in high-end technology fields such as semiconductors, optical fibers, communications, optical instruments, national defense, aerospace, electronic information, and new energy, playing a vital role in modern industrial and technological development and serving as an indispensable key material in modern science and technology.

[0003] The purity of silica in quartz glass is a key technical indicator determining its performance and application areas. Silica content is typically in the range of 99.9% to 99.99%. With the technological advancements in high-end applications such as semiconductors, fiber optic communications, 5G communications, artificial intelligence, and quantum computing, the purity requirements for quartz glass in these fields have gradually increased from the traditional 99.99% to over 99.99%, 99.999%, or even higher. These requirements demand extremely high silica purity, extremely low impurity element content (ppb level), and very few gas-liquid inclusions and inclusions. This stringent quality requirement makes high-purity quartz glass testing technology a crucial link in ensuring the quality and safety of the industry chain.

[0004] Currently, the methods for determining the silica content in quartz glass include the national standard GB / T 3284-2015 "Methods for Chemical Composition Analysis of Quartz Glass", the electronic industry standard SJ / T 3328.4-2016 "High-purity Quartz Sand for Electronic Products - Part 4: Determination of Silica", and the ferrous metallurgical industry standard YB / T 4225-2010 "Methods for Determination of Silica Content in Quartz Sand". All of these methods use the traditional chemical analysis method, the gravimetric method-high-temperature ignition acid digestion differential method. The basic principle is as follows: after grinding, the quartz glass sample is ignited at high temperature (960℃±5℃) to constant weight. The mass fraction reduced is the loss on ignition. Then, it is digested with hydrofluoric acid and sulfuric acid to convert all the silica into silicon tetrafluoride and remove it. It is then ignited to constant weight again. The silica content is calculated by subtracting the loss on ignition and the amount of residue (impurity elements) after acid treatment from the sample weight using the differential method. The high-temperature ignition hydrofluoric acid digestion difference method, as a traditional chemical analysis method, requires precise control of the sample weighing amount (accurate to 0.0001g or more), strict control of ignition temperature, operation time, and laboratory environmental conditions to ensure the accuracy of the test results. It has high requirements for experimental techniques, complicated experimental steps, long time consumption, and high energy consumption due to repeated high-temperature ignition. Based on the above factors, the gravimetric method has great limitations and difficulties in determining ultra-high purity quartz glass samples with a silica content of more than 99.99%.

[0005] The newly formulated national standard, "Determination and Expression Method of Silica Content in High-Purity Quartz" (Project Plan No.: 20250579-T-609), defines silica content using the difference method. The silica content, also known as silica purity, is obtained by subtracting the total percentage content of 15 trace elements from 100%. Quartz glass is composed of main silica, trace impurities, and gas-liquid inclusions. This calculation method cannot objectively reflect the actual silica content in quartz glass primarily for the following two reasons: 1. In addition to the 15 impurities listed in the draft standard, quartz glass may contain other metallic impurities such as barium, zirconium, germanium, cobalt, rubidium, and cesium, as well as non-metallic elements such as fluorine, chlorine, carbon, and hydrogen. These impurities affect the chemical purity of quartz glass. The method only subtracts the total content of the 15 impurities, which lacks theoretical rigor. 2. Quartz glass may contain gas-liquid inclusions due to the raw materials and manufacturing process. These inclusions can be observed under an optical microscope, and their presence affects the chemical purity of the quartz glass. The draft standard does not consider these substances, which is inconsistent with objective reality. Therefore, using the above calculation method to determine the silica content as the silica purity of quartz glass lacks scientific validity and reliability.

[0006] In summary, considering industry demands and technological background factors, the rapid and accurate determination of silica content in quartz glass has become an urgent need for supply chain quality control in the field of quartz glass material applications. Summary of the Invention

[0007] The main objective of this invention is to provide a method for determining silicon dioxide in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry. The technical problem to be solved is to grind the quartz glass sample, add a strong alkali flux for high-temperature melting reaction and heat water to dissolve the reactants, and use inductively coupled plasma atomic emission spectrometry to determine the silicon content in the solution, thereby calculating the silicon dioxide content in the quartz glass sample.

[0008] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry (ICP-AES) according to this invention includes the following steps: Step 1: Crush and grind the quartz glass sample into powder; Step 2: Add a strong alkali flux to the powdered quartz glass sample obtained in Step 1, mix well to obtain a mixture; then melt the mixture at high temperature. Step 3: Extract the reactants with hot water and bring the volume to a final level; Step 4: Plot a standard curve of silicon concentration versus spectral line emission intensity; Step 5: Test the silicon content in the sample solution; Step 6: Calculate the silicon dioxide content based on the measured silicon content.

[0009] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0010] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, in step one, the sample is selected from at least one of quartz glass and its products, quartz glass fibers and their products, natural quartz glass raw materials, and synthetic quartz sand.

[0011] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, in step one, the natural quartz glass raw material is selected from at least one of quartz ore, quartz sand, crystal ore, and crystal powder.

[0012] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, the strong alkaline flux in step two includes at least one of alkali metal carbonates and alkali metal hydroxides.

[0013] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, the strong alkali flux in step two includes at least one of anhydrous sodium carbonate, anhydrous potassium carbonate, sodium hydroxide, and potassium hydroxide.

[0014] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, the mass ratio of the sample to the strong alkali flux in step two is 1:2 to 1:20.

[0015] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, the high-temperature melting temperature in step two is 500℃~1150℃.

[0016] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, the hot water in step three is silica-free ultrapure water.

[0017] Preferably, in the aforementioned method for determining silicon dioxide in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, step four, specifically involves plotting a standard curve of silicon element concentration versus spectral emission intensity, which includes: preparing a series of silicon single-element standard solutions using a silicon element standard solution with a valid national standard sample certificate, measuring the silicon element standard solution, and plotting a standard curve of silicon element concentration versus spectral emission intensity.

[0018] Preferably, in the aforementioned method for determining silicon dioxide in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, in step five, the mass fraction of silicon in the sample solution is... oh si Calculate according to formula (1): ……………………………(1) In the formula: oh si —Mass fraction of silicon in the sample, % C si —The concentration of silicon in the sample solution, expressed in micrograms per milliliter (μg / mL). C 0 —The concentration of silicon in the blank solution, expressed in micrograms per milliliter (μg / mL). V —The volume of the sample solution, in milliliters (mL); f—The factor by which the sample solution is diluted; m —Sample mass, in grams (g).

[0019] Preferably, in the aforementioned method for determining silica in quartz glass based on high-temperature melt reaction-inductively coupled plasma atomic emission spectrometry, in step six, the mass fraction of the silica content... oh siO2 Calculate according to formula (3): …………………(2) ………………(3) In the formula: oh siO2 —Mass fraction of silica in the sample, % oh si —Mass fraction of silicon in the sample, % 28.0855 — the relative atomic mass of silicon; 15.9994 — the relative atomic mass of oxygen; m —Sample mass, in grams (g).

[0020] By employing the above technical solution, the method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry proposed in this invention has at least the following advantages: The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry (ICP-AES) of this invention offers high accuracy (99.99966% for the same sample compared to 99.99% for the gravimetric method), higher precision, shorter experimental time (reduced from 60 hours for the traditional gravimetric method to 10 hours), significantly improved analysis speed, and lower energy consumption (reduced from 5 hours for the high-temperature holding time of the traditional gravimetric method to 0.5 hours). It does not use hazardous or toxic chemical reagents (hydrofluoric acid) and is applicable to the accurate testing of conventional silica content (99.9%~99.99%) and high-purity silica content (above 99.99%) in quartz glass and its products, quartz glass fibers and their products, natural quartz glass raw materials (quartz ore, quartz sand, crystal ore, crystal powder), and synthetic quartz sand. Therefore, the technical solution of this invention significantly improves testing accuracy, efficiency, and safety, while also possessing good applicability and wide applicability.

[0021] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a flowchart of the method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry proposed in this invention. Detailed Implementation

[0023] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features and effects of a method for determining silicon dioxide in quartz glass based on a high-temperature melting reaction-inductively coupled plasma atomic emission spectrometer proposed in accordance with the present invention.

[0024] Some embodiments of the present invention provide a method for determining silica in quartz glass based on high-temperature melt reaction-inductively coupled plasma atomic emission spectrometry, comprising the following steps: Step 1: The sample is crushed and ground into powder. The sample can be selected from at least one of quartz glass and its products, quartz glass fibers and their products, natural quartz glass raw materials (quartz ore, quartz sand, crystal ore, crystal powder), and synthetic quartz sand. The main component of the above quartz products or raw materials is silicon dioxide (99.9% or higher). Quartz ore is crushed and acid-washed to produce quartz sand. High-purity quartz ore is also known as crystal ore. Crystal ore is crushed, acid-washed, and ground into crystal powder. Quartz sand and crystal powder are melted at high temperature without flux to produce quartz glass. Quartz glass is formed and processed into quartz glass products. Quartz glass is drawn into quartz glass fibers and its products. Silicon-containing compounds or silicon are chemically synthesized into high-purity quartz glass. Powder / granules, i.e., synthetic quartz sand; Step two: Add a strong alkali flux to the powdered sample obtained in step one, mix well to obtain a mixture; melt the mixture at high temperature; the strong alkali flux includes at least one of alkali metal carbonates and alkali metal hydroxides; specifically, the strong alkali flux includes at least one of anhydrous sodium carbonate, anhydrous potassium carbonate, sodium hydroxide, and potassium hydroxide; silicon dioxide is an acidic oxide, and this invention is based on the high-temperature melting reaction decomposition of the sample, that is, the acidic oxide and the strong alkali flux undergo a double decomposition reaction at high temperature; using alkali metal carbonates and alkali metal hydroxides as strong alkali fluxes, the quartz is melted at high temperature. The sample is converted into a soluble alkali metal silicate. The core purpose is to convert the inert silicon in the sample into active silicon, which is then tested using inductively coupled plasma atomic emission spectrometry (ICP-AES). The mass ratio of the sample to the strong alkali flux is 1:2 to 1:20. The core purpose of setting the mass ratio of the sample to the flux is to overcome the reaction limitations under the theoretical stoichiometric ratio, ensure the complete decomposition and melting of the quartz glass, and at the same time, the excess flux can make up for the loss of flux volatilization and decomposition at high temperature, greatly increase the flux concentration in the reaction system, and thus continuously promote the forward reaction until the quartz glass is completely decomposed and melted, avoiding sample residue. Step 3: Immerse the reactants in hot water and adjust the volume; the hot water is silicon-free ultrapure water; after the molten reactants cool, they will form a dense glassy solid that is difficult for room temperature water to penetrate. Boiling water can significantly increase the molecular motion rate and accelerate the dissociation of the dense solid, allowing the molten reactants to dissolve quickly and fully into the aqueous solution, ensuring that all the silicon in the molten reactants is transferred to the liquid phase, which is convenient for subsequent analysis and testing. Step 4: Plot a standard curve of silicon concentration versus spectral line emission intensity; Step 5: Test the silicon content in the sample solution; the mass fraction of silicon element in the sample solution. oh si Calculate according to formula (1): ……………………………(1) In the formula: oh si —Mass fraction of silicon in the sample, % C si —The concentration of silicon in the sample solution, expressed in micrograms per milliliter (μg / mL). C 0 —The concentration of silicon in the blank solution, expressed in micrograms per milliliter (μg / mL). V —The volume of the sample solution, in milliliters (mL); f —The factor by which the sample solution is diluted; m —Sample mass, in grams (g).

[0025] Step six: Calculate the silicon dioxide content based on the measured silicon content; the mass fraction of the silicon dioxide content. oh siO2 Calculate according to formula (3): …………………(2) ……………(3) In the formula: oh siO2 —Mass fraction of silica in the sample, % oh si —Mass fraction of silicon in the sample, % 28.0855 — the relative atomic mass of silicon; 15.9994 — the relative atomic mass of oxygen; m —Sample mass, in grams (g).

[0026] In some optional embodiments, the method for determining silica in quartz glass based on high-temperature melt reaction-inductively coupled plasma atomic emission spectrometry may include the following steps: Step 1: Crush the quartz glass sample into particles of approximately 1 mm to 5 mm. This appropriate particle size facilitates subsequent sample grinding. Immerse the crushed particles in hydrochloric acid (acid to water volume ratio 1+1) or nitric acid (acid to water volume ratio 1+1) at 100 ℃ to 105 ℃ for approximately 10-15 minutes to remove surface impurities. Using hydrochloric acid or nitric acid for sample pretreatment allows for selective impurity removal, dissolving metal oxides, carbonates, and external contaminants on the sample surface, preventing impurities from entering the subsequent melting system. The acid solution, at a slight boiling state, will slightly etch the quartz glass surface, weakening the dense silica lattice and facilitating subsequent grinding into powder. Quartz glass only reacts with hydrofluoric acid and hot phosphoric acid; it is almost insoluble under other dilute acid, slight boiling, and short-time (approximately 10 minutes) conditions, resulting in no loss of sample quality after acid immersion. A 1+1 volume ratio of hydrochloric acid / nitric acid and water is a commonly used operation for inorganic experimental sample pretreatment, ensuring thorough impurity removal, ease of subsequent processing, and minimal introduction of additional ions. The acid boiling temperature should not be too high to prevent splashing and physical volatilization. After acid boiling, cool to room temperature and rinse with ultrapure water to remove adsorbed acid radicals and impurity ions from the sample particle surface. Then, dry in an oven at 105 ℃~110 ℃. After cooling, grind to a powder with a particle size of about 0.075 mm (200 mesh). (Note: 1. Fine granular samples such as quartz sand can be ground directly; 2. Quartz glass fibers and products need to be calcined at a high temperature of about 650 ℃ for 5 min~10 min to completely remove the surface wetting agent or binder, and then cut, acid boiled, dried and ground in the same way as the block quartz glass sample processing steps.) If the sample particle size is too large, it will reduce the contact area between the sample and the flux, resulting in incomplete high-temperature melting reaction and thus affecting the test results. Smaller particle size can increase the contact area of ​​the reactants, accelerate the reaction rate, reduce the melting time, and make the reaction more complete. The ground powder sample should be dried in an oven at 105 ℃~110 ℃ for no less than 2 h to fully remove the surface moisture of the sample and make the sample completely dry. Step 2: Weigh the quartz glass powder sample obtained in Step 1 and place it in a dried platinum crucible to avoid water vapor expansion during heating, which could cause the molten material to splash out. Step 3: Add anhydrous sodium carbonate to the powdered quartz glass sample from Step 2, mix well to obtain a mixture, and then melt the mixture at a high temperature of 950℃~1050℃. The chemical equation for the high-temperature melting reaction of silicon dioxide and anhydrous sodium carbonate is: The theoretical stoichiometry is (Molar ratio), converted to mass ratio ≈ 60.08 ( (relative molecular mass): 105.99 The relative molecular mass ratios are approximately 1:1.76. In actual experimental operations, anhydrous sodium carbonate is required as a flux. Based on conventional practical experience with inorganic fusion samples, the optimal mass ratio range is... The key reason is to overcome the reaction limitation under the theoretical stoichiometric ratio (1:1.76), ensuring the complete decomposition and melting of quartz glass. Excess flux can compensate for the loss of flux through volatilization and decomposition at high temperatures, significantly increasing the flux concentration in the reaction system, thereby continuously driving the reaction forward until the quartz glass is completely converted into sodium silicate, avoiding sample residue. Pure The melting point is approximately 1088℃, and the excess in this reaction... Will be generated Forming low melting point The eutectic system lowers the actual melting point of the melt, allowing melting to occur without excessively high temperatures, thus reducing energy consumption and crucible corrosion. It also reduces the viscosity of the melt, ensuring it remains a fluid liquid at high temperatures rather than a viscous paste, allowing for sufficient contact between the flux and quartz particles (increasing reaction rate and melting efficiency) and preventing the melt from sticking to the walls / forming slag. The melting temperature is 950℃~1050℃, a range that ensures complete melting of reactants and a complete reaction while avoiding excessive energy consumption, side reactions, and crucible corrosion. Step four: Immerse the reactants in hot water (boiling water) and bring the volume to a constant. After cooling, the molten product forms a dense, glassy solid that is difficult for room temperature water to penetrate. Boiling water significantly increases the molecular motion rate, accelerating the dissociation of the dense solid and allowing sodium silicate to dissolve quickly and completely into the aqueous solution. This ensures that almost all the silicon in the molten product is transferred to the liquid phase, facilitating subsequent analysis and testing. Simultaneously, it prevents the hydrolysis of sodium silicate to form insoluble silicic acid precipitates, ensuring that silicon exists in the leaching solution in the form of soluble sodium silicate. In the experiment, anhydrous sodium carbonate was used in excess as a flux to ensure complete reaction of silicon dioxide. Boiling water quickly dissolves any residual sodium carbonate, which can be eliminated later through volume adjustment and other operations to eliminate its interference with the test matrix. Step 5: Plot a standard curve of silicon concentration versus spectral emission intensity; Step six: Test the silicon content in the sample solution; Step 7: Calculate the silicon dioxide content based on the measured silicon content.

[0027] The present invention will be further described in detail below with reference to specific embodiments. Example 1

[0028] This embodiment provides a method for determining silica in quartz glass based on high-temperature melt reaction-inductively coupled plasma atomic emission spectrometry, including the following steps: Step 1: Crush the quartz glass sample (ultra-high purity anhydrous quartz glass S1) into fine particles with a particle size of about 2 mm. Soak it in a hydrochloric acid (1+1) solution at 105 ℃ (hydrochloric acid is of analytical grade, with a mass fraction of 40%, and 1+1 is the volume ratio of hydrochloric acid to ultrapure water, specifically, 1 part volume of hydrochloric acid is added to 1 part volume of ultrapure water) for about 10 min. Cool it to room temperature, wash it with ultrapure water, dry it in an oven at 105 ℃, cool it to room temperature, grind it with a grinder to a powder with a particle size of about 0.075 mm (200 mesh), dry it in an oven at 105 ℃ for 2 h, place it in a weighing bottle, and store it in a desiccator. Step 2: Weigh approximately 0.1 g of quartz glass sample, accurate to 0.0001 g, and place it in a dried platinum crucible. Add 0.5 g of anhydrous sodium carbonate, mix well, cover the crucible with a lid, leaving a gap. Place the crucible in a high-temperature furnace and melt it at 1000 °C for 20 min until it reaches a molten state. Add approximately 50 mL of boiling water (silicon-free ultrapure water) to leach (approximately 1 h) the molten reaction mixture into a 250 mL plastic beaker. Step 3: After cooling to room temperature, transfer to a 1000 mL polyethylene volumetric flask and dilute to volume with silica-free ultrapure water; Step four, sample blank test: Without adding a sample, the experiment is performed in parallel with the sample test, following the same analytical steps, reagents, instrument conditions, and operating environment. The purpose is to eliminate interference from non-sample sources and systematic errors throughout the experiment, improving the accuracy of the test results. Reagents, water, glassware leaching or residue, and environmental dust used in the experiment can all generate "false signals." The sample blank can eliminate all these, accurately quantifying the true signal of the sample. The final sample result = sample measured value - sample blank value, making the test result closer to the true content of the sample. High-temperature melting, boiling water extraction, volume adjustment, baseline drift of the detection instrument, and background noise can all introduce minor systematic deviations. The blank test is conducted under identical operating and instrument conditions as the sample test, and the blank value can correct these deviations, improving the accuracy of the measurement results. Step 5: Plot the standard curve. Using commercially available silicon element standard solutions with valid national standard sample certificates, prepare a series of silicon single element standard solutions and determine the silicon element standard solutions at concentrations of 0 μg / mL, 10 μg / mL, 30 μg / mL, 50 μg / mL, 70 μg / mL, and 90 μg / mL to plot the silicon element concentration-spectral line emission intensity standard curve. Step six: Sample solution determination. Using the same test conditions as the standard series solutions, determine the blank solution and sample solution, and compare the corresponding mass concentration by comparing with the silicon element concentration-spectral line emission intensity (CI) standard curve; the mass fraction of silicon element content in the sample. oh siCalculate according to formula (1): ……………………………(1) In the formula: oh si —Mass fraction of silicon in the sample, % C si —The concentration of silicon in the sample solution, expressed in micrograms per milliliter (μg / mL). C 0 —The concentration of silicon in the blank solution, expressed in micrograms per milliliter (μg / mL). V —The volume of the sample solution, in milliliters (mL); f —The factor by which the sample solution is diluted; m —Sample mass, in grams (g).

[0029] Step 7: Mass fraction of silica in the sample oh siO2 Calculate according to formula (3): …………………(2) ……………(3) In the formula: oh siO2 —Mass fraction of silica in the sample, % oh si —Mass fraction of silicon in the sample, % 28.0855 — the relative atomic mass of silicon; 15.9994 — the relative atomic mass of oxygen; m —Sample mass, in grams (g).

[0030] The chemical reaction equation is as follows: Test results of this embodiment oh siO2 =99.99966%. Example 2

[0031] The difference between this embodiment and Embodiment 1 is that the sample in this embodiment is quartz glass S2 synthesized by hydrogen-oxygen flame chemical vapor deposition, while the other steps and parameters are the same as in Embodiment 1.

[0032] Test results of this embodiment oh siO2 =99.90891%. Example 3

[0033] The difference between this embodiment and Embodiment 1 is that the sample in this embodiment is imported quartz sand S3, and the sample is directly ground during pretreatment. The remaining steps and parameters are the same as in Embodiment 1.

[0034] Test results of this embodiment oh siO2 =99.99891%. Example 4

[0035] The difference between this embodiment and Embodiment 1 is that the sample in this embodiment is domestically produced quartz sand S4, and the sample is directly ground during pretreatment. The remaining steps and parameters are the same as in Embodiment 1.

[0036] Test results of this embodiment oh siO2 =99.99772%. Example 5

[0037] The difference between this embodiment and Embodiment 1 is that the sample in this embodiment is natural quartz glass ore S5, while the remaining steps and parameters are the same as in Embodiment 1.

[0038] Test results of this embodiment oh siO2 =99.94198%. Example 6

[0039] The difference between this embodiment and Embodiment 1 is that the sample in this embodiment is quartz glass fiber cloth S6. The sample needs to be calcined at 650 ℃ for 10 min to completely remove the surface wetting agent or adhesive, and then cut, acid-cooked, dried and ground in the same manner as the block quartz glass sample processing steps. The remaining steps and parameters are the same as in Embodiment 1.

[0040] Test results of this embodiment oh siO2 =99.96237%. Example 7

[0041] The difference between this embodiment and embodiment 3 is that the melting temperature in this embodiment is 960 ℃, while the remaining steps and parameters are the same as in embodiment 1.

[0042] Test results of this embodiment oh siO2 =99.99897%. Example 8

[0043] The difference between this embodiment and Embodiment 1 is that the melting temperature in this embodiment is 1020 ℃, while the remaining steps and parameters are the same as in Embodiment 1.

[0044] Test results of this embodiment oh siO2 =99.99959%. Example 9

[0045] The difference between this embodiment and Embodiment 1 is that the melting time in this embodiment is 30 min, while the remaining steps and parameters are the same as in Embodiment 1.

[0046] The test result in this embodiment is 99.99961%. Example 10

[0047] The difference between this embodiment and Example 1 is that 1.0 g of anhydrous sodium carbonate is added in this embodiment, while the remaining steps and parameters are the same as in Example 1.

[0048] Test results of this embodiment oh siO2 =99.99953%. Example 11

[0049] The difference between this embodiment and embodiment 3 is that 0.5 g of anhydrous potassium carbonate is added in this embodiment, while the other steps and parameters are the same as in embodiment 3.

[0050] Test results of this embodiment oh siO2 =99.99887%.

[0051] Comparative Example 1 According to Chapter 5 of the national standard GB / T 3284-2015 "Methods for Chemical Composition Analysis of Quartz Glass - Determination of Loss on Ignition and Silica Content - Subtraction Method for Ignition", ultra-high purity anhydrous quartz glass S1 was tested.

[0052] Test results of this comparative example oh siO2 =99.99%.

[0053] Table 1 shows a comparative analysis of the tests conducted on ultrapure anhydrous quartz glass S1 in Example 1 and Comparative Example 1.

[0054] Table 1

[0055] As can be seen from the data in Table 1, the experiment time for Example 1 was approximately 10 hours, while that for Comparative Example 1 was approximately 60 hours. The test result for Example 1 was 99.99966%, and the test result for Comparative Example 1 was 99.99%. It is evident that the analytical efficiency and test accuracy of Example 1 of the present invention are higher than those of Comparative Example 1.

[0056] Comparative Example 2 The difference between this comparative example and Example 3 is that the melting temperature in this example is 850 ℃, while the remaining steps and parameters are the same as in Example 3.

[0057] Test results of this comparative example oh siO2 =99.06376%.

[0058] Comparative Example 3 The difference between this comparative example and Example 3 is that the melting time in this example is 5 minutes, while the remaining steps and parameters are the same as in Example 3.

[0059] Test results of this comparative example oh siO2 =99.73670%.

[0060] Comparative Example 4 The difference between this comparative example and Example 3 is that 0.2 g of anhydrous sodium carbonate was added in this example, while the remaining steps and parameters are the same as in Example 3.

[0061] Test results of this comparative example oh siO2 =99.28603%.

[0062] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry, characterized in that, Includes the following steps: Step 1: Crush and grind the sample into powder; Step 2: Add a strong alkali flux to the powdered sample obtained in Step 1, mix well to obtain a mixture; then melt the mixture at high temperature. Step 3: Extract the reactants with hot water and bring the volume to a final level; Step 4: Plot a standard curve of silicon concentration versus spectral line emission intensity; Step 5: Test the silicon content in the sample solution; Step 6: Calculate the silicon dioxide content based on the measured silicon content.

2. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 1, characterized in that, In step one, the sample is selected from at least one of quartz glass and its products, quartz glass fiber and its products, natural quartz glass raw materials and synthetic quartz sand.

3. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 2, characterized in that, In step one, the natural quartz glass raw material is selected from at least one of quartz ore, quartz sand, crystal ore and crystal powder.

4. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 1, characterized in that, In step two, the strong alkali flux includes at least one of alkali metal carbonates and alkali metal hydroxides.

5. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 4, characterized in that, In step two, the strong alkali flux includes at least one of anhydrous sodium carbonate, anhydrous potassium carbonate, sodium hydroxide, and potassium hydroxide.

6. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 1, characterized in that, In step two, the mass ratio of the sample to the strong alkali flux is 1:2 to 1:20; the high-temperature melting temperature is 500℃-1150℃.

7. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 1, characterized in that, In step three, the hot water is silicon-free ultrapure water.

8. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 1, characterized in that, In step four, the specific steps of plotting the silicon element concentration-spectral line emission intensity standard curve include: preparing a series of silicon single-element standard solutions using silicon element standard solutions with national standard sample certificates, measuring the silicon element standard solutions, and plotting the silicon element concentration-spectral line emission intensity standard curve.

9. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 1, characterized in that, In step five, the mass fraction of silicon in the sample solution is determined. ω si Calculate according to formula (1): ……………………………（1） In the formula: ω si —Mass fraction of silicon in the sample, % C si —The concentration of silicon in the sample solution, expressed in micrograms per milliliter (μg / mL). C 0 —The concentration of silicon in the blank solution, expressed in micrograms per milliliter (μg / mL). V —The volume of the sample solution, in milliliters (mL); f —The factor by which the sample solution is diluted; m —Sample mass, in grams (g).

10. The method for determining silica in quartz glass based on high-temperature melting reaction-inductively coupled plasma atomic emission spectrometry as described in claim 1, characterized in that, In step six, the mass fraction of the silica content... ω siO2 Calculate according to formula (3): …………………（2） …………………（3） In the formula: ω siO2 —Mass fraction of silica in the sample, % ω si —Mass fraction of silicon in the sample, % 28.0855 — the relative atomic mass of silicon; 15.9994 — the relative atomic mass of oxygen; m —Sample mass, in grams (g).

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