Pretreatment method for digesting glass substrate

Abstract

The invention relates to the technical field of digestion, in particular to a pretreatment method for digesting a glass substrate. The pretreatment method comprises the following four key steps: firstly, crushing and grinding a glass substrate sample into powder so as to increase the contact area and accelerate the subsequent reaction speed; next, adding a mixture of ammonium bifluoride and ammonium fluoride and the powder sample into a polytetrafluoroethylene beaker, adding a small amount of water for wetting, and then adding concentrated hydrochloric acid and concentrated nitric acid to effectively promote the dissolution of the sample; then, the beaker is placed on a heating plate to be heated and digested, and after it is confirmed that the sample is completely digested by monitoring the state of the solution, the sample is cooled to the room temperature. And finally, transferring the digestion solution to a volumetric flask, rinsing the original beaker for multiple times with pure water, and diluting to a constant volume. According to the method, the digestion time is remarkably shortened, the background interference is reduced, the detection precision is improved, and the method is particularly suitable for the requirements of high-end analysis equipment such as AAS and ICP.

Description

Technical Field

[0001] The present invention relates to the field of digestion technology, and particularly to a pretreatment method for digesting glass substrates. Background Art

[0002] In current technologies, the pretreatment methods for the inspection of glass substrate products face several major challenges. First, since glass substrates contain a high proportion of silicon dioxide (SiO2) that is difficult to digest, with its content ranging from 65% to 75%, it is quite difficult to use either alkali digestion or acid digestion methods. Although the alkali digestion method can convert insoluble substances into soluble substances through double decomposition reactions at high temperatures, this method requires the addition of various co-solvents such as sodium carbonate, potassium carbonate, and sodium hydroxide, resulting in increased background interference and affecting test results, especially for trace element analysis.

[0003] On the other hand, the acid digestion method uses nitric acid, sulfuric acid, hydrochloric acid, perchloric acid, and highly dangerous hydrofluoric acid, etc., for digestion at high temperatures. Although this method reduces the amount and types of reagents, thereby reducing background interference and improving test accuracy, in order to effectively process glass substrates rich in SiO2, hydrofluoric acid must be used, which is a significant safety hazard. In addition, different heating methods, including heating plate heating, graphite furnace heating, and microwave heating, have their own advantages and disadvantages. For example, although graphite furnace heating can provide a uniform heating effect and can efficiently process samples in batches, its applicable range is relatively narrow and the operation is complex; while microwave heating is fast and efficient, but it faces high equipment costs. The heating plate has a low cost but low efficiency.

[0004] In the patent with the publication number CN102854053B, in step 1, ammonium bifluoride and geological samples are mixed in a certain mass ratio and then heated at a high temperature (220 - 240 °C) for 3 - 5 hours. This process utilizes the effective digestion of ammonium bifluoride on geological samples at high temperatures and can be regarded as a solid-phase reaction process. Steps 2 and 3 involve using acids and other solvents to further process the preliminarily digested samples. In step 2, acid is added and heated to remove silicon elements; while in step 3, acid and water are added again, and the remaining solid residues are completely dissolved in the solution by heating. This patent takes a long time and affects the test progress.

[0005] In summary, there is still room for improvement in the existing pretreatment methods for the inspection of glass substrate products. An ideal method should be able to ensure the complete digestion of samples while not significantly increasing the digestion time or operation difficulty, and should meet the requirements of high-end analytical equipment such as atomic absorption spectrometry (AAS) and inductively coupled plasma (ICP). Therefore, it is particularly important to develop a new pretreatment method to solve the above-mentioned problems of efficiency, safety, and accuracy. Summary of the Invention

[0006] (1) Technical Problem to be Solved

[0007] In view of the above-mentioned disadvantages and deficiencies of the prior art, the present invention provides a pretreatment method for digesting glass substrates, which solves the technical problem of long digestion time in traditional digestion methods.

[0008] (2) Technical Solution

[0009] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0010] 1. A pretreatment method for digesting glass substrates, characterized by comprising the following steps:

[0011] S1. Crush and grind the glass substrate sample to obtain a powder sample;

[0012] S2. Mix ammonium bifluoride and ammonium fluoride, add the obtained mixture and the powder sample in step S1 into a polytetrafluoroethylene beaker, moisten with a small amount of water, and then add an appropriate amount of concentrated hydrochloric acid and concentrated nitric acid;

[0013] S3. Place the polytetrafluoroethylene beaker in step S2 on a hot plate for heating and digestion, and after confirming that the sample is completely digested, cool it to room temperature;

[0014] S4. Transfer the digested solution to a volumetric flask, rinse the beaker 3 - 4 times with pure water and then dilute to a fixed volume.

[0015] In some embodiments, in step S1, the powder sample obtained after grinding the glass substrate is further ground so that the powder passes through a test sieve with a pore size of at least Φ100μm. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0016] The finer the powder particles, the larger their total surface area, which enables the digestion reagents (such as ammonium bifluoride, ammonium fluoride, concentrated hydrochloric acid and concentrated nitric acid) to more fully contact and act on each component in the sample. Especially for glass substrates containing a high proportion of silicon dioxide (SiO2), a larger contact area helps to accelerate the chemical reaction rate and dissolve insoluble substances faster. Since the powder sample is finely ground, increasing the contact area with the digestion reagents, the total time required to complete digestion can be greatly reduced. Compared with large particle samples without refinement treatment, fine powder samples can usually reach a completely digested state in a shorter time, thus improving the working efficiency of the entire analysis process.

[0017] In some embodiments, in step S2, the mass ratio of the mixture of ammonium bifluoride and ammonium fluoride to the powder sample of the glass substrate is 6 - 10:1.

[0018] Both ammonium bifluoride and ammonium fluoride have good complexing ability and the ability to dissolve silicon dioxide. By mixing these two reagents in an appropriate ratio, the synergistic effect between them can be enhanced, and the SiO2 structure in the glass substrate can be destroyed more effectively. Especially when the mass ratio of ammonium bifluoride to ammonium fluoride is set at 6 - 10:1, their complexing effect can be maximized, accelerating the dissolution process of insoluble substances.

[0019] Selecting the appropriate mass ratio of the mixture of ammonium bifluoride and ammonium fluoride to the glass substrate powder sample (6 - 10:1) can ensure the digestion efficiency while avoiding excessive use of reagents. The appropriate amount of reagents not only reduces costs but also reduces background interference, contributing to improving the detection accuracy. In addition, a reasonable reagent ratio helps to control the reaction rate, making the entire digestion process more controllable and efficient.

[0020] When the mass ratio of ammonium bifluoride to ammonium fluoride is within the range of 6 - 10:1, the synergistic effect of the two reagents reaches the optimal state. Ammonium bifluoride provides sufficient fluoride ions and an acidic environment, while ammonium fluoride enhances the complexing effect by supplementing an appropriate amount of fluoride ions, enabling SiO2 to decompose quickly.

[0021] When the mass ratio of the mixture of ammonium bifluoride and ammonium fluoride to the glass substrate powder sample is maintained within the range of 6 - 10:1, the digestion time required can be significantly shortened.

[0022] In some embodiments, in step S2, the mass ratio of the mixture of ammonium bifluoride and ammonium fluoride is 11 - 14:1.

[0023] The main component of the glass substrate is silicon dioxide (SiO2), which has stable chemical properties and is difficult to decompose. Ammonium bifluoride and ammonium fluoride release fluoride ions to react with SiO2 through complexation reactions, generating soluble fluorosilicates (such as H2SiF6), thereby achieving the complete decomposition of the sample. When the mass ratio of ammonium bifluoride to ammonium fluoride is 11 - 14:1, ammonium bifluoride serves as the main fluorine source, providing a sufficient fluoride ion concentration, while an appropriate amount of ammonium fluoride supplements additional fluoride ions to maintain efficient complexation. This ratio enables SiO2 to be dissolved quickly and completely. Within this ratio range, the synergistic effect of the reagents reaches the optimal state, and the digestion of the sample can be completed in a relatively short time. For example, in some embodiments, the digestion time can be shortened to about 20 minutes, far lower than the 30 - 50 minutes or even longer required by traditional methods. Due to the precise control of the dosages of ammonium bifluoride and ammonium fluoride, the generation of unnecessary by-products is reduced, thereby reducing background interference and improving detection accuracy. This is particularly important for trace element analysis. When the mass ratio of ammonium bifluoride to ammonium fluoride is 11 - 14:1, the functions of the two reagents reach a balance, ensuring both a sufficient fluoride ion concentration and avoiding uneven reactions caused by excessively high or low local concentrations. This balance helps the sample to dissolve quickly and evenly throughout the digestion process, avoiding the problem of incomplete digestion in some areas.

[0024] When the proportion of ammonium bifluoride is too high, although its ability to dissolve silicon dioxide is strong, due to the relatively insufficient content of ammonium fluoride, the complexation of fluoride ions is not balanced enough. The role of ammonium fluoride is to provide additional fluoride ions and cooperate with ammonium bifluoride to accelerate the destruction of SiO2. If ammonium fluoride is insufficient, the complexation efficiency of ammonium bifluoride will be limited, thus slowing down the overall digestion rate. Excessive ammonium bifluoride leads to too high a local reagent concentration, forming a strong acidic environment, which causes a protective silica gel layer (such as SiO2·nH2O) to form on the surface of the sample in some areas, hindering further chemical reactions and prolonging the digestion time. When the proportion of ammonium bifluoride is too low, the amount of fluoride ions it provides is not sufficient to effectively break the SiO2 structure in the glass substrate, resulting in a decrease in digestion efficiency. Although ammonium fluoride can provide a certain amount of fluoride ions, its dissolution ability is far less than that of ammonium bifluoride. Ammonium bifluoride is not only a source of fluoride ions but also provides a certain acidic environment to promote sample dissolution. When its proportion is insufficient, the acidity of the solution is not strong enough to maintain an efficient digestion reaction, thus prolonging the digestion time. In the case of insufficient ammonium bifluoride, the insoluble components (such as SiO2) in the sample cannot be fully decomposed and require a longer time to reach a completely digested state. When

[0025] In some embodiments, in step S2, a small amount of pure water is first added for wetting, and then concentrated hydrochloric acid and concentrated nitric acid with a volume ratio of 2-4:1 are added. The amounts of the added concentrated hydrochloric acid and concentrated nitric acid and the previous small amount of water ensure that the mixture of ammonium bifluoride and ammonium fluoride and the glass substrate powder are just completely covered. The amount of water is not strictly required. Generally, the volume ratio of the water to the total volume of the acid is controlled at 0.5-1.5:6.

[0026] First, a small amount of pure water is added to wet the mixture of ammonium bifluoride, ammonium fluoride, and the glass substrate powder sample, and then concentrated hydrochloric acid and concentrated nitric acid are added in a volume ratio of 2-4:1 to ensure that the acid solution just completely covers all the solid substances. This operation method not only optimizes the usage amount of the reagent but also significantly shortens the digestion time. The addition of a small amount of pure water plays a role of preliminary wetting, enabling the mixture of ammonium bifluoride, ammonium fluoride, and the glass substrate powder sample to be more evenly dispersed, avoiding the phenomenon of excessive local concentration caused by directly adding strong acids. This helps the subsequent uniform penetration of the acid solution and promotes the consistency and thoroughness of the chemical reaction. By adding concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 2-4:1, the synergistic effect of these two strong acids not only provides the necessary acidic environment but also enhances the oxidation ability and promotes the rapid dissolution of insoluble substances. The reasonable ratio of concentrated hydrochloric acid and concentrated nitric acid can avoid the waste caused by excessive acid solution and unnecessary background interference while ensuring sufficient reaction. By ensuring that the acid solution just completely covers all the solid substances and controlling the volume ratio of water to the total volume of the acid at 0.5-1.5:6, the liquid amount in the reaction system can be precisely regulated. An appropriate amount of water helps to adjust the concentration of the acid solution so that it will not be overly diluted and affect the reaction rate. This optimized treatment method can complete the thorough digestion of the glass substrate sample in about 20 minutes, saving a large amount of time and energy consumption compared with the traditional method. This is because the appropriate moisture wetting combined with the reasonable acid ratio configuration can quickly initiate and maintain an efficient chemical reaction, thus accelerating the decomposition process of the sample.

[0027] In some embodiments, in step S3, the digestion time is 20-30 min.

[0028] Traditional methods usually take several hours to complete the thorough digestion of the glass substrate sample. By optimizing the reagent ratio and operating conditions (such as the mass ratio of ammonium bifluoride to ammonium fluoride being 11-14:1 and using an appropriate ratio of concentrated hydrochloric acid and concentrated nitric acid), the complete digestion of the sample can be achieved within 20-30 minutes. This greatly shortens the processing cycle and improves the overall working efficiency of the laboratory. During this time period, due to the addition of an appropriate amount of pure water for wetting and a reasonable ratio of concentrated hydrochloric acid and concentrated nitric acid in the early stage, it can ensure that ammonium bifluoride and ammonium fluoride fully act on the insoluble components in the glass substrate. These conditions work together to completely decompose the sample in a short time, avoiding test errors caused by incomplete digestion.

[0029] In some embodiments, in step S3, the temperature of the heating plate is controlled between 220 - 250 °C.

[0030] Within this temperature range, ammonium bifluoride and ammonium fluoride can more effectively release fluoride ions (F - ), and undergo a complexation reaction with silicon dioxide (SiO2) in the glass substrate. High temperature helps to increase the reaction rate, enabling the poorly soluble SiO2 to be converted into soluble fluorosilicates more quickly, thus accelerating the digestion process of the sample. The temperature range of 220 - 250 °C is sufficient to provide enough energy to break the complex chemical bond structure in the glass substrate, ensuring that all components in the sample can be fully dissolved. Especially at this temperature, the oxidation ability of concentrated hydrochloric acid and concentrated nitric acid is also enhanced, further promoting the decomposition of the sample. This temperature range is carefully selected to ensure rapid and effective digestion, without causing unnecessary side reactions or sample volatilization loss due to excessive temperature. For example, if the temperature is too low, the activity of the reagent cannot be fully activated, resulting in incomplete digestion; while if the temperature is too high, some components will decompose or volatilize excessively, affecting the accuracy of the test results.

[0031] In some embodiments, in step S3, after digestion for 15 min, observe whether the solution becomes clear every 2 - 3 min. When the solution becomes clear, the digestion is complete.

[0032] By regularly checking the state of the solution, the progress of the digestion process can be understood in real time. This allows the operator to flexibly adjust the digestion time according to the actual situation, avoiding over - digestion or incomplete digestion caused by a fixed time.

[0033] In some embodiments, in step S5, add 2 ml of a scandium or palladium elemental standard solution with a concentration of 1 mg / L, and then dilute and make up the volume with dilute nitric acid with a mass ratio of 2%.

[0034] Scandium or palladium, as an internal standard, is mainly used to correct instrument drift and sample matrix effects. Since the composition of the glass substrate sample is complex, which will affect the signal intensity and stability of the elements to be measured, by adding a known - concentration scandium or palladium standard solution, these effects can be effectively compensated, thereby improving the accuracy and reliability of the final analysis results. Diluting and making up the volume of the digested solution with 2% dilute nitric acid can not only adjust the solution to the optimal concentration range suitable for instrument detection, but also avoid corrosion or damage to the instrument caused by high - concentration acid, and extend the service life of the equipment.

[0035] A pretreatment method for digesting a glass substrate, characterized by comprising:

[0036] Step 1: Crush and grind the glass substrate sample to obtain a powder sample, and further grind the powder sample so that the powder passes through a test sieve with a pore size of Φ100 μm at least;

[0037] Step 2: Add ammonium bifluoride and the powder sample in Step 1 into a polytetrafluoroethylene beaker. The mass ratio of ammonium bifluoride to the powder sample of the glass substrate is 6 - 10:1. Add a small amount of water to moisten it, then add appropriate amounts of concentrated hydrochloric acid and concentrated nitric acid. The volume ratio of concentrated hydrochloric acid to concentrated nitric acid is 2 - 4:1. The amounts of concentrated hydrochloric acid and concentrated nitric acid added are ensured to just completely cover the ammonium bifluoride and the glass substrate powder.

[0038] Step 3: Place the polytetrafluoroethylene beaker in Step S2 on a heating plate for heating and digestion. After confirming that the sample is completely digested, cool it to room temperature. The digestion time is 30 - 50 min, and the temperature of the heating plate is controlled between 220 - 250 °C. After 25 min of digestion, observe whether the solution becomes clear every 2 - 3 min. When the solution becomes clear, the digestion is complete.

[0039] Step 4: Transfer the digested solution to a volumetric flask, add 2 ml of a scandium or palladium element single standard solution with a concentration of 1 mg / L, rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio.

[0040] Although the digestion time of this method is slightly longer than that when ammonium bifluoride and ammonium fluoride are used in combination, due to the adoption of appropriate reagent ratios and strict monitoring steps, it can still achieve efficient and thorough digestion, while improving the detection accuracy and data reliability, meeting the requirements of high-end analytical equipment such as atomic absorption spectrometry and inductively coupled plasma.

[0041] (III) Beneficial effects

[0042] The beneficial effects of the present invention are as follows: This pretreatment method for digesting glass substrates achieves effective digestion of glass substrate samples containing a high proportion of silicon dioxide (SiO2) through a series of carefully designed steps, while ensuring the safety of the operation and the accuracy of the test results. First, the glass substrate sample is crushed and ground to increase its contact area, which helps to accelerate the speed and efficiency of subsequent chemical reactions (S1). Then, a mixture of ammonium bifluoride and ammonium fluoride is used, and it is placed in a polytetrafluoroethylene beaker together with the glass powder for pretreatment. After adding a small amount of water to moisten it, concentrated hydrochloric acid and concentrated nitric acid are added. This process can effectively promote the dissolution of the sample (S2). Subsequently, the mixture is heated and digested on a hot plate to ensure that the sample is completely dissolved in the solution. At the same time, the digestion is confirmed to be complete by monitoring the state of the solution, and then it is cooled to room temperature (S3). Finally, the obtained digestion solution is transferred to a volumetric flask, and the original beaker is rinsed with pure water multiple times to collect all target substances. After dilution and volume fixation, it can be used for further analysis (S4). This method not only significantly shortens the digestion time, reduces background interference, but also improves the detection accuracy, especially meeting the requirements of high-end analytical equipment such as atomic absorption spectrometry and inductively coupled plasma, thus providing reliable technical support for the quality control of glass substrate products.

[0043] This pretreatment method for digesting glass substrates significantly shortens the digestion time by optimizing the reagent combination and operating conditions. Traditional methods (such as alkali digestion method or acid digestion method relying solely on hydrofluoric acid) usually take several hours or even longer to complete the thorough digestion of samples rich in silicon dioxide (SiO2). However, this method can greatly shorten the digestion time to 20 - 30 minutes under high-temperature conditions by introducing a mixture of ammonium bifluoride and ammonium fluoride and combining the synergistic effect of concentrated hydrochloric acid and concentrated nitric acid. This significant time shortening is mainly due to the following points: First, the reasonable ratio of ammonium bifluoride to ammonium fluoride (mass ratio of 11 - 14:1) can efficiently break the insoluble SiO2 structure in the glass substrate; second, the addition of concentrated hydrochloric acid and concentrated nitric acid further enhances the oxidation and dissolution ability, promoting the rapid decomposition of the sample; third, the heating temperature is controlled within the range of 220 - 250 °C, which not only ensures the reaction rate but also avoids excessive energy consumption or reagent volatilization loss. Compared with the digestion process of traditional methods that often take several hours, this method not only improves the experimental efficiency but also reduces energy consumption and operation complexity, thus providing a more efficient and convenient solution for large-scale sample detection. Specific embodiments

[0044] In this application, both the examples and comparative examples were repeated multiple times. The data in the text are the averages of multiple data, and the difference in digestion time for each test is not more than 4 min.

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0046] Example 1

[0047] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ75 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0048] Step 2: Weigh 800 mg of ammonium bifluoride and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce the environmental pollution to the sample. Transferring it to the fume hood is because acid digestion will be carried out later, which can reduce the impact of acid mist on the environment and people.

[0049] Step 3: Add a small amount of pure water to the polytetrafluoroethylene beaker for wetting, take 1.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 2 ml of concentrated nitric acid, cover the lid, and gently shake for 10 s. Adding pure water for wetting and then adding acid can ensure that the sample is thoroughly wetted, facilitating the digestion reaction.

[0050] Step 4: Adjust the temperature of the hot plate, control the digestion temperature at 220 °C, place the beaker on the hot plate, and heat and digest for 30 - 50 min.

[0051] Step 5: After heating and digesting for 30 min, observe whether the solution becomes clear every 3 min. The digestion time will not exceed 50 min, and the solution becomes clear. Wait until the solution becomes clear, indicating that the digestion is complete. The digestion time this time is 48 min. Place it in the fume hood with the lid covered and let it cool to room temperature.

[0052] Step 6: Transfer it to a plastic volumetric flask, then add 2 ml of a scandium or palladium element single standard solution with a concentration of 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent the hydrolytic deposition of the digested sample, serving as Test Sample 1.

[0053] Step 7: Use an ICP instrument to test Test Sample 1 respectively, and the test results are shown in Table 1.

[0054] Example 2

[0055] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0056] Step 2: Weigh 600mg of ammonium bifluoride and 100mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce environmental pollution to the sample. Transferring to the fume hood is because acid digestion will be carried out subsequently, reducing the impact of acid mist on the environment and people.

[0057] Step 3: Add a small amount of pure water to the polytetrafluoroethylene beaker for wetting, take 0.5ml of water, then add 4ml of concentrated hydrochloric acid and 1ml of concentrated nitric acid, cover the lid, and gently shake for 10s. Adding pure water for wetting and then adding acid can ensure complete wetting of the sample, facilitating the digestion reaction.

[0058] Step 4: Adjust the temperature of the hot plate, control the digestion temperature at 250°C, place the beaker on the heating plate, and heat and digest for 30 - 50min.

[0059] Step 5: After heating and digesting for 30min, observe whether the solution becomes clear every 3min. The digestion time will not exceed 50min, and the solution becomes clear. The digestion time for this time is 30min. After the solution becomes clear, the digestion is complete. Place it in the fume hood with the lid covered and cool it to room temperature.

[0060] Step 6: Transfer it to a plastic volumetric flask, then add 2ml of a scandium or palladium element single - standard solution with a concentration of 1mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. After rinsing the beaker 3 - 4 times with pure water, transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as Test Sample 2.

[0061] Step 7: Use an ICP instrument to test Test Sample 2 respectively, and the test results are shown in Table 1.

[0062] Example 3

[0063] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ50μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0064] Step 2: Weigh 1000 mg of ammonium bifluoride and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the beaker with a lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce environmental contamination of the sample. Transferring it to the fume hood is because acid digestion will be carried out later, reducing the impact of acid mist on the environment and people.

[0065] Step 3: Add a small amount of pure water to the polytetrafluoroethylene beaker to moisten it. Take 1 ml of water, then add 3 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid. Cover the lid and gently shake for 10 s. Adding pure water to moisten and then adding acid can ensure that the sample is thoroughly wetted, facilitating the digestion reaction.

[0066] Step 4: Adjust the temperature of the hot plate and control the digestion temperature at 250 °C. Place the beaker on the hot plate and heat for digestion for 30 - 50 min.

[0067] Step 5: After heating for digestion for 30 min, observe whether the solution becomes clear every 5 min. The digestion time will not exceed 50 min, and the solution becomes clear. The digestion time for this time is 40 min. After the solution becomes clear, it means complete digestion. Place it in the fume hood, cover the lid, and let it cool to room temperature.

[0068] Step 6: Transfer it to a plastic volumetric flask, then add 2 ml of scandium or palladium elemental standard solution. The concentration of the standard solution is 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as Test Sample 3.

[0069] Step 7: Use an ICP instrument to test Test Sample 3 respectively, and the test results are shown in Table 1.

[0070] Example 4

[0071] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ75 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0072] Step 2: Weigh 733 mg of ammonium bifluoride, 67 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the beaker with a lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce environmental contamination of the sample. Transferring it to the fume hood is because acid digestion will be carried out later, reducing the impact of acid mist on the environment and people.

[0073] Step 3: Moisten a small amount of pure water in a polytetrafluoroethylene beaker. Take 1.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 2 ml of concentrated nitric acid. Cover the beaker with a lid and gently shake for 10 s. Add pure water to moisten first and then add the acids to ensure that the sample is thoroughly wetted, facilitating the digestion reaction.

[0074] Step 4: Adjust the temperature of the hot plate and control the digestion temperature at 220 °C. Place the beaker on the hot plate and heat for digestion for 20 - 30 min.

[0075] Step 5: After heating for digestion for 15 min, observe whether the solution becomes clear every 3 min. The digestion time will not exceed 30 min. When the solution becomes clear, the digestion is complete. The digestion time for this time is 30 min. Cover the beaker with a lid in the fume hood and let it cool to room temperature.

[0076] Step 6: Transfer to a plastic volumetric flask, then add 2 ml of a scandium or palladium element single standard solution with a concentration of 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask. Dilute and make up the volume with 2% nitric acid by mass ratio to prevent the hydrolytic deposition of the digested sample, serving as test sample 4.

[0077] Step 7: Use an ICP instrument to test test sample 4 respectively. The test results are shown in Table 2.

[0078] Example 5

[0079] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0080] Step 2: Weigh 560 mg of ammonium bifluoride, 40 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the beaker with a lid, and transfer it to the fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it reduces environmental pollution to the sample. Transferring to the fume hood is because subsequent acid addition and digestion will be carried out, reducing the impact of acid mist on the environment and people.

[0081] Step 3: Moisten a small amount of pure water in a polytetrafluoroethylene beaker. Take 0.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid. Cover the beaker with a lid and gently shake for 10 s. Add pure water to moisten first and then add the acids to ensure that the sample is thoroughly wetted, facilitating the digestion reaction.

[0082] Step 4: Adjust the temperature of the hot plate and control the digestion temperature at 250 °C. Place the beaker on the hot plate and heat for digestion for 20 - 30 min.

[0083] Step 5: After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. Once the solution becomes clear, the digestion is complete. The digestion time will not exceed 30 min. The solution becomes clear, and the digestion time for this time is 20 min. Cover it with a lid in the fume hood and let it cool to room temperature.

[0084] Step 6: Transfer it to a plastic volumetric flask, then add 2 ml of scandium or palladium elemental standard solution. The concentration of the standard solution is 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask. Then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent the hydrolytic deposition of the digested sample, serving as test sample 5.

[0085] Step 7: Use an ICP instrument to test test sample 5 respectively. The test results are shown in Table 2.

[0086] Example 6

[0087] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0088] Step 2: Weigh 923 mg of ammonium bifluoride, 77 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover it with a lid, and transfer it to the fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; reduce the environmental pollution to the sample. Transferring it to the fume hood is because acid addition and digestion will be carried out later to reduce the impact of acid mist on the environment and people.

[0089] Step 3: Add a small amount of pure water to the polytetrafluoroethylene beaker for wetting, take 1 ml of water, then add 3 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid, cover it with a lid, and gently shake for 10 s. Adding pure water for wetting and then adding acid can ensure that the sample is thoroughly wetted, facilitating the digestion reaction.

[0090] Step 4: Adjust the temperature of the hot plate, control the digestion temperature at 230 °C, place the beaker on the heating plate, and heat and digest for 20 - 30 min.

[0091] Step 5: After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. Once the solution becomes clear, the digestion is complete. The digestion time will not exceed 30 min. The solution becomes clear, and the digestion time for this time is 26 min. Cover it with a lid in the fume hood and let it cool to room temperature.

[0092] Step 6: Transfer to a plastic volumetric flask, then add 2 ml of a standard solution of scandium or palladium elemental substance with a concentration of 1 mg / L. The standard solution serves as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask. Dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as test sample 6.

[0093] Step 7: Use an ICP instrument to test test sample 6 respectively, and the test results are shown in Table 2.

[0094] Comparative Example 1

[0095] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ50 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0096] Step 2: Weigh 1000 mg of ammonium fluoride and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it reduces environmental pollution to the sample. Transferring to the fume hood is because acid digestion will be carried out subsequently, reducing the impact of acid mist on the environment and people.

[0097] Step 3: Add a small amount of pure water to wet the polytetrafluoroethylene beaker, take 1 ml of water, then add 3 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid, cover the lid, and gently shake for 10 s. Adding pure water to wet first and then adding acid can ensure complete wetting of the sample and facilitate the digestion reaction.

[0098] Step 4: Adjust the temperature of the hot plate, control the digestion temperature at 250 °C, place the beaker on the heating plate, and heat and digest for 30 - 50 min.

[0099] Step 5: After heating and digesting for 30 min, observe whether the solution becomes clear every 5 min. The digestion time will not exceed 50 min, and the solution becomes clear. The digestion time for this time is 32 min. Wait until the solution becomes clear, then the digestion is complete. Place it in the fume hood with the lid covered and cool it to room temperature.

[0100] Step 6: Transfer to a plastic volumetric flask, then add 2 ml of a standard solution of scandium or palladium elemental substance with a concentration of 1 mg / L. The standard solution serves as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask. Dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as test sample 7.

[0101] Step 7: Use an ICP instrument to test test sample 7 respectively, and the test results are shown in Table 3.

[0102] Comparative Example 2

[0103] Step 1. Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0104] Step 2. Weigh 300 mg of ammonium bifluoride, 300 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the beaker with a lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can also reduce environmental pollution to the sample. Transferring it to the fume hood is because subsequent acid digestion will be carried out to reduce the impact of acid mist on the environment and people.

[0105] Step 3. Add a small amount of pure water (0.5 ml) to the polytetrafluoroethylene beaker to moisten it, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid, cover the lid, and gently shake for 10 s. Adding pure water to moisten it first and then adding acid can ensure that the sample is thoroughly wetted, facilitating the digestion reaction.

[0106] Step 4. Adjust the temperature of the hot plate to control the digestion temperature at 250 °C, place the beaker on the hot plate, and heat and digest for 30 - 50 min.

[0107] Step 5. After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. When the solution becomes clear, the digestion is complete. The digestion time will not exceed 50 min. In this case, the solution becomes clear and the digestion time is 41 min. Place it in the fume hood with the lid on and let it cool to room temperature.

[0108] Step 6. Transfer it to a plastic volumetric flask, then add 2 ml of a single-element standard solution of scandium or palladium. The concentration of the standard solution is 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent the hydrolytic deposition of the digested sample, serving as Test Sample 8.

[0109] Step 7. Use an ICP instrument to test Test Sample 8 respectively. The test results are shown in Table 3.

[0110] Comparative Example 3

[0111] Step 1. Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0112] Step 2: Weigh 600 mg of ammonium bifluoride, 300 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the lid, and transfer it to the fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce environmental contamination of the sample. Transferring it to the fume hood is because acid digestion will be carried out later, reducing the impact of acid mist on the environment and people.

[0113] Step 3: Add a small amount of pure water to the polytetrafluoroethylene beaker to moisten it. Take 0.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid, cover the lid, and gently shake for 10 s. Adding pure water to moisten it first and then adding acid can ensure complete wetting of the sample, facilitating the digestion reaction.

[0114] Step 4: Adjust the temperature of the hot plate to control the digestion temperature at 250 °C. Place the beaker on the hot plate and heat and digest for 30 - 50 min.

[0115] Step 5: After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. Wait until the solution becomes clear, indicating complete digestion. The digestion time will not exceed 50 min. The solution becomes clear, and the digestion time for this time is 45 min. Place it in the fume hood, cover the lid, and let it cool to room temperature.

[0116] Step 6: Transfer it to a plastic volumetric flask, then add 2 ml of a single-element standard solution of scandium or palladium. The concentration of the standard solution is 1 mg / L. The standard solution serves as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask. Dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as Test Sample 9.

[0117] Step 7: Use an ICP instrument to test Test Sample 9 respectively. The test results are shown in Table 3.

[0118] Comparative Example 4

[0119] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0120] Step 2: Weigh 500 mg of ammonium bifluoride, 100 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the lid, and transfer it to the fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce environmental contamination of the sample. Transferring it to the fume hood is because acid digestion will be carried out later, reducing the impact of acid mist on the environment and people.

[0121] Step 3: Moisten a small amount of pure water in a polytetrafluoroethylene beaker. Take 0.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid. Cover the beaker with a lid and gently shake for 10 s. Add acid after moistening with pure water to ensure complete wetting of the sample, facilitating the digestion reaction.

[0122] Step 4: Adjust the temperature of the hot plate to control the digestion temperature at 250 °C. Place the beaker on the hot plate and heat for digestion for 30 - 50 min.

[0123] Step 5: After heating for digestion for 15 min, observe whether the solution becomes clear every 3 min. When the solution becomes clear, the digestion is complete. The digestion time will not exceed 50 min. The solution becomes clear, and the digestion time for this time is 39 min. Place it in the fume hood with the lid on and let it cool to room temperature.

[0124] Step 6: Transfer to a plastic volumetric flask, then add 2 ml of a single-element standard solution of scandium or palladium. The concentration of the standard solution is 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask. Dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as the test sample 10.

[0125] Step 7: Use an ICP instrument to test the test sample 10 respectively. The test results are shown in Table 3.

[0126] Comparative Example 5

[0127] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0128] Step 2: Weigh 550 mg of ammonium bifluoride, 55 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the beaker with a lid, and transfer it to the fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; reduce environmental pollution to the sample. Transferring to the fume hood is because acid digestion will be carried out later to reduce the impact of acid mist on the environment and people.

[0129] Step 3: Moisten a small amount of pure water in a polytetrafluoroethylene beaker. Take 0.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid. Cover the beaker with a lid and gently shake for 10 s. Add acid after moistening with pure water to ensure complete wetting of the sample, facilitating the digestion reaction.

[0130] Step 4: Adjust the temperature of the hot plate to control the digestion temperature at 250 °C. Place the beaker on the hot plate and heat for digestion for 30 - 50 min.

[0131] Step 5: After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. Once the solution becomes clear, the digestion is complete. The digestion time will not exceed 50 min. The solution becomes clear, and the digestion time for this time is 33 min. Cover it with a lid in the fume hood and let it cool to room temperature.

[0132] Step 6: Transfer it to a plastic volumetric flask, then add 2 ml of scandium or palladium elemental standard solution. The concentration of the standard solution is 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. Rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask. Then dilute and make up the volume with 2% nitric acid by mass ratio to prevent the hydrolytic deposition of the digested sample, serving as the test sample 11.

[0133] Step 7: Use an ICP instrument to test the test sample 11 respectively. The test results are shown in Table 3.

[0134] Comparative Example 6

[0135] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0136] Step 2: Weigh 600 mg of ammonium bifluoride, 40 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover it with a lid, and transfer it to the fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; reduce the environmental pollution to the sample. Transferring it to the fume hood is because subsequent acid addition and digestion will be carried out to reduce the impact of acid mist on the environment and people.

[0137] Step 3: Add a small amount of pure water to wet the polytetrafluoroethylene beaker, take 0.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid, cover it with a lid, and gently shake for 10 s. Adding pure water to wet it first and then adding acid can ensure complete wetting of the sample and facilitate the digestion reaction.

[0138] Step 4: Adjust the temperature of the hot plate to control the digestion temperature at 250 °C, place the beaker on the heating plate, and heat and digest for 30 - 50 min.

[0139] Step 5: After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. Once the solution becomes clear, the digestion is complete. The digestion time will not exceed 50 min. The solution becomes clear, and the digestion time for this time is 38 min. Cover it with a lid in the fume hood and let it cool to room temperature.

[0140] Step 6: Transfer to a plastic volumetric flask, then add 2 ml of a standard solution of scandium or palladium elemental substance with a concentration of 1 mg / L. The standard solution serves as an internal standard to eliminate the deviation caused by the instrument. After rinsing the beaker 3 - 4 times with pure water, transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as test sample 12.

[0141] Step 7: Use an ICP instrument to test test sample 12 respectively, and the test results are shown in Table 3.

[0142] Comparative Example 7

[0143] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100 μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0144] Step 2: Weigh 600 mg of ammonium bifluoride, 30 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce environmental pollution to the sample. Transferring to the fume hood is because acid digestion will be carried out subsequently to reduce the impact of acid mist on the environment and people.

[0145] Step 3: Add a small amount of pure water to wet the polytetrafluoroethylene beaker, take 0.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid, cover the lid, and gently shake for 10 s. Adding pure water to wet and then adding acid can ensure complete wetting of the sample, facilitating the digestion reaction.

[0146] Step 4: Adjust the temperature of the hot plate, control the digestion temperature at 250 °C, place the beaker on the heating plate, and heat and digest for 30 - 50 min.

[0147] Step 5: After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. When the solution becomes clear, the digestion is complete. The digestion time will not exceed 50 min. The solution becomes clear, and the digestion time for this time is 48 min. Place it in the fume hood with the lid on and let it cool to room temperature.

[0148] Step 6: Transfer to a plastic volumetric flask, then add 2 ml of a standard solution of scandium or palladium elemental substance with a concentration of 1 mg / L. The standard solution serves as an internal standard to eliminate the deviation caused by the instrument. After rinsing the beaker 3 - 4 times with pure water, transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent hydrolysis and deposition of the digested sample, serving as test sample 13.

[0149] Step 7: Use an ICP instrument to test test sample 13 respectively, and the test results are shown in Table 3.

[0150] Comparative Example 8

[0151] Step 1: Physically crush the glass substrate sample in an agate mortar and grind it until it can pass through a test sieve with a pore size of Φ100μm to obtain a powder sample for standby. The increased contact area of the powder sample facilitates subsequent digestion and shortens the digestion time.

[0152] Step 2: Weigh 1120 mg of ammonium bifluoride, 80 mg of ammonium fluoride, and 100 mg of the powder sample from Step 1, place them in a clean polytetrafluoroethylene beaker, cover the lid, and transfer it to a fume hood. Covering the lid can prevent the powder sample from flying and affecting the weighing; it can reduce environmental pollution to the sample. Transferring it to the fume hood is because acid digestion will be carried out subsequently, reducing the impact of acid mist on the environment and people.

[0153] Step 3: Add a small amount of pure water to the polytetrafluoroethylene beaker for wetting, take 0.5 ml of water, then add 4 ml of concentrated hydrochloric acid and 1 ml of concentrated nitric acid, cover the lid, and gently shake for 10 s. Adding pure water for wetting and then adding acid can ensure complete wetting of the sample, facilitating the digestion reaction.

[0154] Step 4: Adjust the temperature of the hot plate, control the digestion temperature at 250 °C, place the beaker on the hot plate, and heat and digest for 30 - 50 min.

[0155] Step 5: After heating and digesting for 15 min, observe whether the solution becomes clear every 3 min. When the solution becomes clear, the digestion is complete. The digestion time will not exceed 50 min. The solution becomes clear, and the digestion time for this time is 40 min. Place it in the fume hood with the lid covered and cool it to room temperature.

[0156] Step 6: Transfer it to a plastic volumetric flask, then add 2 ml of a single-element standard solution of scandium or palladium. The concentration of the standard solution is 1 mg / L. The standard solution is used as an internal standard to eliminate the deviation caused by the instrument. After rinsing the beaker 3 - 4 times with pure water, transfer it to the volumetric flask, and then dilute and make up the volume with 2% dilute nitric acid by mass ratio to prevent the hydrolytic deposition of the digested sample, serving as Test Sample 14.

[0157] Step 7: Use an ICP instrument to test Test Sample 14 respectively, and the test results are shown in Table 3.

[0158] Table 1: Data of Examples 1 - 3

[0159]

[0160]

[0161] Table 2: Data of Examples 4 - 6

[0162] Analysis element Sample 4 Sample 5 Sample 6 Reference result Sc (mg / L) 0.97 0.98 1.01 1.00±0.05 Si (%) 31.79 31.53 31.93 31.79±1.50 Na (%) 5.91 5.95 6.10 5.93±0.20 K(％) 3.23 3.32 3.41 3.32±0.15 Ca (%) 2.82 2.88 2.93 2.86±0.12 Mg (%) 2.44 2.47 2.48 2.41±0.10 Al(％) 2.07 2.13 2.18 2.12±0.10 Fe (%) 0.036 0.035 0.034 0.035±0.003 B(％) 2.45 2.49 2.52 2.48±0.10 Digestion time (min) 30 20 26 NA

[0163] Table 3: Data of Comparative Examples 1-8

[0164] Analysis element Sample 7 Sample 8 Sample 9 Sample 10 Reference result Sc (mg / L) 0.96 1.00 1.03 0.99 1.00±0.05 Si (%) 31.59 31.68 31.39 31.31 31.79±1.50 Na (%) 5.83 5.76 6.04 5.88 5.93±0.20 K(％) 3.22 3.29 3.41 3.19 3.32±0.15 Ca (%) 2.96 2.81 2.74 2.91 2.86±0.12 Mg (%) 2.39 2.42 2.37 2.36 2.41±0.10 Al(％) 2.08 2.14 2.11 2.20 2.12±0.10 Fe (%) 0.0032 0.036 0.033 0.036 0.035±0.003 B(％) 2.39 2.51 2.49 2.51 2.48±0.10 Digestion time (min) 32 41 45 39 NA Analysis element Sample 11 Sample 12 Sample 13 Sample 14 Reference result Sc (mg / L) 0.95 0.97 1.04 1.03 1.00±0.05 Si (%) 31.49 31.55 32.16 31.12 31.79±1.50 Na (%) 5.94 6.04 6.11 5.92 5.93±0.20 K(％) 3.38 3.26 3.10 3.25 3.32±0.15 Ca (%) 2.88 2.79 2.88 2.93 2.86±0.12 Mg (%) 2.49 2.38 2.36 2.38 2.41±0.10 Al(％) 2.15 2.20 2.19 2.08 2.12±0.10 Fe (%) 0.034 0.036 0.038 0.035 0.035±0.003 B(％) 2.41 2.50 2.52 2.53 2.48±0.10 Digestion time (min) 33 38 48 40 NA

[0165] As can be seen from the above table, the scandium concentrations of all the examples and comparative examples are close to the reference value (1.00 ±

[0166] 0.05 mg / L), indicating that the experimental operations and the instrument testing process are relatively stable without obvious deviations. Although the digestion time in the comparative examples is longer, the effective decomposition of the samples can still be achieved. However, through the optimized treatment methods (as shown in Examples 4-6), the complete decomposition of the samples can be completed in a shorter time (20 minutes to 30 minutes), demonstrating higher digestion efficiency.

[0167] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A pretreatment method for digesting a glass substrate, characterized in that, It includes the following steps: S1. Crush and grind the glass substrate sample to obtain a powder sample; S2. Mix ammonium bifluoride and ammonium fluoride, add the obtained mixture and the powder sample in step S1 into a polytetrafluoroethylene beaker, moisten with a small amount of water, and then add an appropriate amount of concentrated hydrochloric acid and concentrated nitric acid; S3. Place the polytetrafluoroethylene beaker in step S2 on a hot plate for heating digestion. After confirming that the sample is completely digested, cool it to room temperature; S4. Transfer the digested solution to a volumetric flask, rinse the beaker 3 - 4 times with pure water and then dilute and make up the volume.

2. The method according to claim 1, characterized in that, In step S1, the powder sample obtained after grinding the glass substrate is further ground so that the powder passes through a test sieve with a pore size of Φ100μm at least.

3. The method according to claim 1, wherein In step S2, the mass ratio of the mixture of ammonium bifluoride and ammonium fluoride to the powder sample of the glass substrate is 6 - 10:

1.

4. The method according to claim 1, wherein In step S2, the mass ratio of ammonium bifluoride to ammonium fluoride is (11 - 14):

1.

5. The method according to claim 1, characterized in that, In step S2, the volume ratio of concentrated hydrochloric acid to concentrated nitric acid is (2 - 4):1, and the amounts of concentrated hydrochloric acid and concentrated nitric acid added are ensured to just completely cover the mixture of ammonium bifluoride, ammonium fluoride and the glass substrate powder.

6. The method according to claim 1, characterized in that In step S3, the digestion time is 20 - 30 min.

7. The method according to claim 1, wherein In step S3, the temperature of the hot plate is controlled between 220 - 250 °C.

8. The method according to claim 1, characterized in that, In step S3, after digestion for 15 min, observe whether the solution becomes clear every 2 - 3 min. When the solution becomes clear, the digestion is complete.

9. The method according to claim 1, characterized in that, In step S5, add 2 ml of a scandium or palladium element single standard solution with a concentration of 1 mg / L, and then dilute and make up the volume with dilute nitric acid with a mass ratio of 2%.

10. A pretreatment method for digesting a glass substrate, characterized in that, It includes: Step 1. Crush and grind the glass substrate sample to obtain a powder sample, and further grind the powder sample so that the powder passes through a test sieve with a pore size of Φ100μm at least; Step 2. Add ammonium bifluoride and the powder sample in step 1 into a polytetrafluoroethylene beaker. The mass ratio of ammonium bifluoride to the powder sample of the glass substrate is (6 - 10):1, moisten with a small amount of water, and then add an appropriate amount of concentrated hydrochloric acid and concentrated nitric acid. The volume ratio of concentrated hydrochloric acid to concentrated nitric acid is 2 - 4:1, and the amounts of concentrated hydrochloric acid and concentrated nitric acid added are ensured to just completely cover ammonium bifluoride and the glass substrate powder; Step 3. Place the polytetrafluoroethylene beaker in step S2 on a hot plate for heating digestion. After confirming that the sample is completely digested, cool it to room temperature; the digestion time is 30 - 50 min, the temperature of the hot plate is controlled between 220 - 250 °C, after digestion for 25 min, observe whether the solution becomes clear every 2 - 3 min. When the solution becomes clear, the digestion is complete; Step 4. Transfer the digested solution to a volumetric flask, add 2 ml of a scandium or palladium element single standard solution with a concentration of 1 mg / L, rinse the beaker 3 - 4 times with pure water and then transfer it to the volumetric flask, and then dilute and make up the volume with dilute nitric acid with a mass ratio of 2%.

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