Digestion method for detecting components of ceramic powder

Abstract

The invention relates to the technical field of ceramic powder component detection, in particular to a digestion method for ceramic powder component detection. The method comprises the following specific steps: grinding and carrying out ultrasonic pretreatment, adding 1-dodecyl-3-methylimidazole bromide and tetrasodium iminodisuccinate before digestion, and setting a microwave digestion program; according to the present invention, the 1-dodecyl-3-methylimidazole bromide is added, such that the 1-dodecyl-3-methylimidazole bromide can easily destroy the crystal structure of the ceramic powder so as to easily react with sulfuric acid, such that the full digestion reaction can be easily performed so as to improve the digestion efficiency; tetrasodium iminodisuccinate is added after nitric acid due to the fact that the tetrasodium iminodisuccinate can form a stable chelate with metal ions in ceramic powder, in the digestion process, the metal ions can be effectively prevented from being subjected to hydrolysis or precipitation or oxidation or other reactions, the metal ions are kept in a stable ionic state in a solution, and therefore follow-up component detection is better facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic powder component detection, in particular to a digestion method for ceramic powder component detection. Background Art

[0002] Ceramics are an indispensable and important material in many fields such as medicine, automobiles, solar energy, and decoration. However, ceramic materials usually contain impurity elements such as iron, manganese, and magnesium, and different fields have different requirements for the content of these impurity elements. Therefore, it is very important to detect the composition of solid materials. However, due to the stable chemical properties of ceramic materials, the relevant analysis methods are currently scarce, and the digestion effect is not satisfactory and often takes a long time. This has brought challenges to the precise application of ceramic materials in various fields. In view of this, we propose a digestion method for ceramic powder composition detection. Summary of the invention

[0003] The purpose of the present invention is to provide a digestion method for detecting the composition of ceramic powders, so as to solve the problem mentioned in the above background technology that due to the stable chemical properties of ceramic materials, the current relevant analysis methods are relatively scarce, the digestion effect is unsatisfactory, and it is often time-consuming.

[0004] To achieve the above object, the present invention provides a digestion method for detecting the composition of ceramic powders, comprising the following steps:

[0005] S1.1, grinding the sample by a vibration grinder, and then sieving to obtain a ground sample;

[0006] Weigh 0.2 g of the sample into a centrifuge tube, add 4 ml of sulfuric acid, mix well, and then perform ultrasonic treatment at an ultrasonic power of 100-140 W for 20-25 min; immediately add 1-dodecyl-3-methylimidazolium bromide into the centrifuge tube and perform ultrasonic treatment to mix well;

[0007] Ceramic materials have stable chemical properties and are difficult to digest. 1-Dodecyl-3-methylimidazolium bromide helps to destroy the crystal structure of ceramic powders, making them more likely to react with sulfuric acid, thereby improving digestion efficiency and shortening digestion time. After adding this substance, ceramic powders can be better dispersed in sulfuric acid solution, avoiding powder agglomeration, which is conducive to the full digestion reaction, making the digested solution more uniform and improving the accuracy of component detection. It can reduce the surface tension of the solution, make the contact between sulfuric acid and ceramic powders more complete, enhance the interaction between the two, promote the digestion reaction, and thus improve the completeness of digestion. In the subsequent detection process, such as using instruments such as inductively coupled plasma emission spectrometers for component detection, 1-dodecyl-3-methylimidazolium bromide helps to improve the ionization efficiency of elements in the sample, thereby improving the sensitivity and accuracy of detection. In addition, it can prevent certain volatile or oxidizable components from being lost or changed during digestion and subsequent treatment, ensuring that the test results can truly reflect the original component content in the ceramic powder.

[0008] S1.2, transfer the mixture containing sulfuric acid and 1-dodecyl-3-methylimidazolium bromide together with the sample into a digestion tube, and add 4 ml of nitric acid;

[0009] Then add tetrasodium iminodisuccinate to the digestion tube and shake it gently; seal the digestion tube, place it on a magnetic stirrer, adjust the pH with dilute sulfuric acid, and stir continuously;

[0010] Tetrasodium iminodisuccinate is a chelating agent with excellent performance. It can form stable chelates with metal ions in ceramic powders. During the digestion process, it can effectively prevent metal ions from undergoing hydrolysis, precipitation or oxidation reactions, so that metal ions can maintain a stable ionic state in the solution, which is more conducive to subsequent component detection and improves the accuracy and reliability of detection; it helps to break the stable structure of ceramic powders, allowing digestion reagents such as sulfuric acid and nitric acid to more fully contact and react with the components in the ceramic powder, thereby accelerating the digestion speed, shortening the digestion time, and improving the detection efficiency; it can increase the stability and uniformity of the solution, avoid incomplete digestion or detection errors caused by excessively high or low local concentrations, and enable the digested solution to maintain stable chemical properties in subsequent processing and detection processes, reducing the interference of external factors on the detection results.

[0011] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10min; the second stage is to raise the temperature from 200℃ to 220℃ within 3min;

[0012] After digestion is completed and cooled, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well.

[0013] Preferably, the nitric acid, sulfuric acid, 1-dodecyl-3-methylimidazolium bromide and tetrasodium iminodisuccinate are all of high purity;

[0014] Preferably, in S1.1, the amplitude of the vibration grinder is 2-4 mm, the grinding frequency is 30-50 Hz, and the grinding time is 10-20 min.

[0015] Preferably, in S1.1, the powder particle size of the ground sample is 60-100 mesh.

[0016] Preferably, in S1.1, the ultrasonic power for ultrasonic mixing is 60-100 W, and the ultrasonic time is 5-10 min.

[0017] Preferably, in S1.2, the speed of gently shaking is 10-30 times per minute.

[0018] Preferably, in S1.2, the concentration of dilute sulfuric acid is 0.05-0.5 mol / L.

[0019] Preferably, in S1.2, the pH value is adjusted to 6-7 by dilute sulfuric acid.

[0020] Preferably, in S1.2, the stirring speed is 200-400 rpm, and the stirring time is 5-15 min.

[0021] Preferably, in S1.3, the temperature is raised to 200°C and maintained for 5 minutes in the initial heating stage, and the temperature is raised to 220°C and maintained for 30 minutes in the second heating stage.

[0022] Preferably, in S1.3, the oscillation frequency is 150-200 times / minute, the amplitude is 2-3 cm, and the oscillation time is 1-3 min.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. In the digestion method for detecting the composition of ceramic powders, 1-dodecyl-3-methylimidazolium bromide is added because 1-dodecyl-3-methylimidazolium bromide helps to destroy the crystal structure of the ceramic powder, making it easier to react with sulfuric acid, thereby improving the digestion efficiency and shortening the digestion time; it can make the ceramic powder better dispersed in the sulfuric acid solution, avoid powder agglomeration, and be conducive to the full progress of the digestion reaction, making the digested solution more uniform, and improving the accuracy of component detection; it can reduce the surface tension of the solution, make the contact between sulfuric acid and ceramic powder more complete, enhance the interaction between the two, promote the progress of the digestion reaction, and thus improve the completeness of the digestion;

[0025] 2. In the digestion method for ceramic powder component detection, tetrasodium iminodisuccinate is added because it can form a stable chelate with the metal ions in the ceramic powder. During the digestion process, it can effectively prevent the metal ions from undergoing hydrolysis, precipitation or oxidation reactions, so that the metal ions can maintain a stable ionic state in the solution, which is more conducive to subsequent component detection and improves the accuracy and reliability of detection; it can chelate with some impurity ions that may interfere with component detection, remove them from the solution or reduce their activity, thereby reducing the interference of impurities on the detection of target elements and improving the selectivity and sensitivity of detection. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1: A digestion method for detecting the composition of ceramic powders, comprising the following steps:

[0028] S1.1. Grind the sample with a vibration grinder, the amplitude of the vibration grinder is 3 mm, the grinding frequency is 40 Hz, the grinding time is 20 min, and then sieve to obtain a powder sample with a particle size of 100 mesh;

[0029] Weigh 0.2g of the sample into a centrifuge tube, add 4ml of sulfuric acid, mix well, and then perform ultrasonic treatment at an ultrasonic power of 120W for 20min; immediately add 1-dodecyl-3-methylimidazolium bromide into the centrifuge tube, perform ultrasonic treatment and mix well at an ultrasonic power of 100W for 5min;

[0030] S1.2, transfer the mixture containing sulfuric acid and 1-dodecyl-3-methylimidazolium bromide together with the sample into a digestion tube, and add 4 ml of nitric acid;

[0031] Then, tetrasodium iminodisuccinate was added to the digestion tube and gently shaken at a speed of 20 times / minute; after the digestion tube was sealed, it was placed on a magnetic stirrer, and the pH was adjusted to 7 with dilute sulfuric acid with a concentration of 0.1 mol / L, and stirred continuously at a speed of 300 rpm for 15 minutes;

[0032] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10 minutes, and keep it at 200℃ for 5 minutes; the second stage is to raise the temperature from 200℃ to 220℃ within 3 minutes, and keep it at 220℃ for 30 minutes;

[0033] After digestion and cooling, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well with an oscillation frequency of 150 times / minute, an amplitude of 3cm, and an oscillation time of 3min.

[0034] Embodiment 2: A digestion method for detecting the composition of ceramic powders, comprising the following steps:

[0035] S1.1. Grind the sample with a vibration grinder, the amplitude of the vibration grinder is 3 mm, the grinding frequency is 40 Hz, the grinding time is 20 min, and then sieve to obtain a powder sample with a particle size of 80 mesh;

[0036] Weigh 0.2g of the sample into a centrifuge tube, add 4ml of sulfuric acid, mix well, and then perform ultrasonic treatment at an ultrasonic power of 120W for 20min; immediately add 1-dodecyl-3-methylimidazolium bromide into the centrifuge tube, perform ultrasonic treatment and mix well at an ultrasonic power of 100W for 5min;

[0037] S1.2, transfer the mixture containing sulfuric acid and 1-dodecyl-3-methylimidazolium bromide together with the sample into a digestion tube, and add 4 ml of nitric acid;

[0038] Then, tetrasodium iminodisuccinate was added to the digestion tube and gently shaken at a speed of 20 times / minute; after the digestion tube was sealed, it was placed on a magnetic stirrer, and the pH was adjusted to 7 with dilute sulfuric acid with a concentration of 0.1 mol / L, and stirred continuously at a speed of 300 rpm for 15 minutes;

[0039] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10 minutes, and keep it at 200℃ for 5 minutes; the second stage is to raise the temperature from 200℃ to 220℃ within 3 minutes, and keep it at 220℃ for 30 minutes;

[0040] After digestion and cooling, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well with an oscillation frequency of 150 times / minute, an amplitude of 3cm, and an oscillation time of 3min.

[0041] Embodiment 3: A digestion method for detecting the composition of ceramic powders, comprising the following steps:

[0042] S1.1. Grind the sample with a vibration grinder. The amplitude of the vibration grinder is 3 mm, the grinding frequency is 40 Hz, and the grinding time is 20 min. Then, sieve the sample to obtain a powder with a particle size of 60 mesh.

[0043] Weigh 0.2g of the sample into a centrifuge tube, add 4ml of sulfuric acid, mix well, and then perform ultrasonic treatment at an ultrasonic power of 120W for 20min; immediately add 1-dodecyl-3-methylimidazolium bromide into the centrifuge tube, mix well, and perform ultrasonic treatment at an ultrasonic power of 100W for 5min;

[0044] S1.2, transfer the mixture containing sulfuric acid and 1-dodecyl-3-methylimidazolium bromide together with the sample into a digestion tube, and add 4 ml of nitric acid;

[0045] Then, tetrasodium iminodisuccinate was added to the digestion tube and gently shaken at a speed of 20 times / minute; after the digestion tube was sealed, it was placed on a magnetic stirrer, and the pH was adjusted to 7 with dilute sulfuric acid with a concentration of 0.1 mol / L, and stirred continuously at a speed of 300 rpm for 15 minutes;

[0046] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10 minutes, and keep it at 200℃ for 5 minutes; the second stage is to raise the temperature from 200℃ to 220℃ within 3 minutes, and keep it at 220℃ for 30 minutes;

[0047] After digestion and cooling, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well with an oscillation frequency of 150 times / minute, an amplitude of 3cm, and an oscillation time of 3min.

[0048] Comparative Example 1

[0049] S1.1, weigh 0.2g of the sample and put it into a centrifuge tube, add 4ml sulfuric acid, mix well and then perform ultrasonic treatment, the ultrasonic power is 120W, and the ultrasonic time is 20min; immediately add 1-dodecyl-3-methylimidazolium bromide into the centrifuge tube, perform ultrasonic treatment and mix well, the ultrasonic power is 100W, and the ultrasonic time is 5min;

[0050] S1.2, transfer the mixture containing sulfuric acid and 1-dodecyl-3-methylimidazolium bromide together with the sample into a digestion tube, and add 4 ml of nitric acid;

[0051] Then, tetrasodium iminodisuccinate was added to the digestion tube and gently shaken at a speed of 20 times / minute; after the digestion tube was sealed, it was placed on a magnetic stirrer, and the pH was adjusted to 7 with dilute sulfuric acid with a concentration of 0.1 mol / L, and stirred continuously at a speed of 300 rpm for 15 minutes;

[0052] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10 minutes, and keep it at 200℃ for 5 minutes; the second stage is to raise the temperature from 200℃ to 220℃ within 3 minutes, and keep it at 220℃ for 30 minutes;

[0053] After digestion and cooling, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well with an oscillation frequency of 150 times / minute, an amplitude of 3cm, and an oscillation time of 3min.

[0054] Comparative Example 2

[0055] The method of Example 3 was used to remove 1-dodecyl-3-methylimidazolium bromide.

[0056] S1.1. Grind the sample with a vibration grinder. The amplitude of the vibration grinder is 3 mm, the grinding frequency is 40 Hz, and the grinding time is 20 min. Then, sieve the sample to obtain a powder with a particle size of 60 mesh.

[0057] Weigh 0.2 g of the sample into a centrifuge tube, add 4 ml of sulfuric acid, mix well, and then perform ultrasonic treatment at an ultrasonic power of 120 W for 20 min.

[0058] S1.2. Transfer the sample containing sulfuric acid into the digestion tube and add 4 ml nitric acid;

[0059] Then, tetrasodium iminodisuccinate was added to the digestion tube and gently shaken at a speed of 20 times / minute; after the digestion tube was sealed, it was placed on a magnetic stirrer, and the pH was adjusted to 7 with dilute sulfuric acid with a concentration of 0.1 mol / L, and stirred continuously at a speed of 300 rpm for 15 minutes;

[0060] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10 minutes, and keep it at 200℃ for 5 minutes; the second stage is to raise the temperature from 200℃ to 220℃ within 3 minutes, and keep it at 220℃ for 30 minutes;

[0061] After digestion and cooling, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well with an oscillation frequency of 150 times / minute, an amplitude of 3cm, and an oscillation time of 3min.

[0062] Comparative Example 3

[0063] S1.1. Grind the sample with a vibration grinder. The amplitude of the vibration grinder is 3 mm, the grinding frequency is 40 Hz, and the grinding time is 20 min. Then, sieve the sample to obtain a powder with a particle size of 60 mesh.

[0064] Weigh 0.2g of the sample into a centrifuge tube, add 4ml of sulfuric acid, mix well, and then perform ultrasonic treatment at an ultrasonic power of 120W for 20min; immediately add 1-dodecyl-3-methylimidazolium bromide into the centrifuge tube, mix well, and perform ultrasonic treatment at an ultrasonic power of 100W for 5min;

[0065] S1.2, transfer the mixture containing sulfuric acid and 1-dodecyl-3-methylimidazolium bromide together with the sample into a digestion tube, and add 4 ml of nitric acid;

[0066] After the digestion tube is sealed, it is placed on a magnetic stirrer, and the pH is adjusted to 7 with 0.1 mol / L dilute sulfuric acid, and stirred continuously at a speed of 300 rpm for 15 min.

[0067] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10 minutes, and keep it at 200℃ for 5 minutes; the second stage is to raise the temperature from 200℃ to 220℃ within 3 minutes, and keep it at 220℃ for 30 minutes;

[0068] After digestion and cooling, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well with an oscillation frequency of 150 times / minute, an amplitude of 3cm, and an oscillation time of 3min.

[0069] Comparative Example 4

[0070] S1.1, weigh 0.2g of sample and put it into a centrifuge tube, add 4ml sulfuric acid, mix well and then perform ultrasonic treatment, the ultrasonic power is 120W, and the ultrasonic time is 20min;

[0071] S1.2. Transfer the sample containing sulfuric acid to a digestion tube and add 4 ml nitric acid; add it to the digestion tube and gently shake it at a speed of 20 times / minute; seal the digestion tube, place it on a magnetic stirrer, adjust the pH to 7 with dilute sulfuric acid with a concentration of 0.1 mol / L, and stir continuously at a speed of 300 rpm for 15 minutes;

[0072] S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10 minutes, and keep it at 200℃ for 5 minutes; the second stage is to raise the temperature from 200℃ to 220℃ within 3 minutes, and keep it at 220℃ for 30 minutes;

[0073] After digestion and cooling, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well with an oscillation frequency of 150 times / minute, an amplitude of 3cm, and an oscillation time of 3min.

[0074] S1.4. Add 10 mL of saturated boric acid solution to the precipitate in S1.3 and perform a second digestion.

[0075] The present invention adopts a digestion method for detecting the composition of ceramic powders by grinding, ultrasonic pretreatment, and adding 1-dodecyl-3-methylimidazolium bromide and tetrasodium iminodisuccinate before digestion. The specific test results are as follows:

[0076] By measuring the three elements in the ceramic composite powder, standard solutions of the components to be tested with a concentration of 100 μg / mL Fe, Mg, and Mn were added to the blank reagent, and a quantitative test was performed using an inductively coupled plasma emission spectrometer. The standard solution was first determined, and then the sample was measured to obtain the content of the component to be tested.

[0077] The same sample was tested three times in parallel, the results of each test were recorded, and the spike recoveries and relative standard deviations of the three elements in the ceramic composite powder were calculated.

[0078] According to the above standards, the data obtained are shown in Table 1:

[0079] Table 1 Test data of Examples 1-3 and Comparative Examples 1-4

[0080] Implementation / Comparative Example Spiked recovery % Relative standard deviation% Example 1 99.6 1.53 Example 2 99.7 1.46 Example 3 99.9 1.42 Comparative Example 1 70.1 5.03 Comparative Example 2 76.2 4.86 Comparative Example 3 76.4 4.72 Comparative Example 4 68.9 5.23

[0081] It can be seen from Table 1 that Examples 1-3 all have higher spiked recoveries and lower relative standard deviations.

[0082] As the best example, Example 3, combined with Comparative Example 1, shows that without grinding and ultrasonic treatment, the spiked recovery rates of the three elements in the ceramic composite powder are significantly reduced, and the relative standard deviation is significantly increased;

[0083] The main purpose of grinding is to reduce the particle size of ceramic composite powder. The metal elements in ceramic composite powder may exist in the core part of the particles. During the digestion process, only the elements on the surface of large particles that have not been ground can react with the digestion reagent, and the internal elements cannot be released, resulting in a significant decrease in the spike recovery rate; ultrasonic treatment helps to disperse the agglomerated ceramic composite powder. Without ultrasonic treatment, the powder may agglomerate together, which will reduce the contact area between the elements and the digestion reagent. The digestion reagent cannot fully penetrate into the agglomerate, making these elements unable to be completely dissolved into the solution, ultimately reducing the recovery rate of the elements; lack of grinding and ultrasonic treatment, during the digestion process, the powder close to the addition point of the digestion reagent may react violently, while the powder far away from the addition point will not react sufficiently due to insufficient mixing, resulting in uneven release of elements, which reduces the spike recovery rate, and due to the different degree of unevenness of each reaction, the relative standard deviation is also significantly reduced.

[0084] Taking Example 3 as the optimal example, it can be seen from Comparative Example 2 that when 1-dodecyl-3-methylimidazolium bromide is removed, the spiked recoveries of the three elements in the ceramic composite powder are significantly reduced, and the relative standard deviation is significantly increased;

[0085] Removing 1-dodecyl-3-methylimidazolium bromide will cause aggregation on the surface of the ceramic composite powder, while the internal element content will be relatively reduced. When adding the standard substance, it is difficult for the standard substance to fully contact the internal elements, which will reduce the recovery rate, increase the difference in the results of multiple measurements, and increase the relative standard deviation; 1-dodecyl-3-methylimidazolium bromide has a certain solubilizing effect. After its removal, the solubility of the ceramic composite powder in the subsequent sample pretreatment solvent will become worse. During the digestion operation, the elements cannot be fully transferred to the solution, resulting in a low measured value and a decrease in the spike recovery rate;

[0086] Further comparing Example 3 with Comparative Example 3, it can be seen that when tetrasodium iminodisuccinate is removed, the spiked recoveries of the three elements in the ceramic composite powder are significantly reduced, and the relative standard deviations are significantly increased;

[0087] Tetrasodium iminodisuccinate forms a complex with the three elements in the ceramic composite powder. When it is removed, the original complex state of the elements is broken and converted into a chemical form that is more difficult to dissolve or detect, resulting in a reduction in the content of the elements that can be effectively detected during the subsequent extraction and detection process, thereby reducing the spike recovery rate; under acidic extraction conditions, tetrasodium iminodisuccinate can promote the elements to fully react with acid and dissolve, but after removal, the reaction of the elements with acid is inhibited and the recovery rate decreases; tetrasodium iminodisuccinate helps to decompose the structure of the ceramic composite powder, making the elements The elements are exposed, but after removal, some elements in the digested sample are still wrapped in the incompletely decomposed ceramic structure, resulting in a lower recovery rate. In addition, due to the difference in the degree of digestion each time, the relative standard deviation will also increase. The removal of tetrasodium iminodisuccinate may introduce new interfering substances or change the signal response of the elements. During the instrumental analysis process, the new interfering substances may overlap with the signals of the elements or interfere with the ionization process of the elements, reducing the intensity of the characteristic spectral lines of the elements, lowering the measured values, and reducing the spike recovery rate. At the same time, the relative standard deviation increases due to signal instability.

[0088] Combining Example 3 with Comparative Example 4, it can be seen that the spiked recoveries of the three elements in the ceramic composite powder are significantly reduced and the relative standard deviations are significantly increased by the conventional secondary digestion method.

[0089] During the secondary digestion process, some element compounds with lower boiling points may be converted into gaseous state and volatilize under high temperature and acidic environment, thereby reducing the measured element content and the spike recovery rate; the complex composition of the ceramic composite powder itself may also produce some adsorbent substances after digestion, resulting in the elements being adsorbed and unable to be completely transferred to the solution for determination, thereby affecting the recovery rate and relative standard deviation; the composition of the ceramic composite powder is relatively complex, and may contain a high temperature and corrosion resistant crystalline phase structure, in which the encapsulated elements are difficult to be dissolved by acid under conventional digestion conditions, resulting in low element determination values, reduced recovery rate, and increased relative standard deviation; the conventional secondary digestion method itself may have certain limitations. For some specific ceramic composite powders or some elements therein, this method may not achieve the ideal digestion effect; the secondary digestion process involves multiple operation steps, such as sample weighing, reagent addition, digestion time and temperature control, etc. If there is inconsistency in the operation process, such as inaccurate sample amount weighed each time, deviation in reagent addition, inaccurate digestion time and temperature control, etc., it will lead to differences in digestion effect, thereby affecting the recovery rate and relative standard deviation.

[0090] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A digestion method for detecting the composition of ceramic powders, characterized in that: The following steps are involved: S1.1, grinding the sample by a vibration grinder, and then sieving to obtain a ground sample; Weigh 0.2 g of the sample into a centrifuge tube, add 4 ml of sulfuric acid, mix well, and then perform ultrasonic treatment at an ultrasonic power of 100-140 W for 20-25 min; immediately add 1-dodecyl-3-methylimidazolium bromide into the centrifuge tube and perform ultrasonic treatment to mix well; S1.2, transfer the mixture containing sulfuric acid and 1-dodecyl-3-methylimidazolium bromide together with the sample into a digestion tube, and add 4 ml of nitric acid; Then add tetrasodium iminodisuccinate to the digestion tube and shake it gently; seal the digestion tube, place it on a magnetic stirrer, adjust the pH with dilute sulfuric acid, and stir continuously; S1.3, set the digestion program of the microwave digestion instrument, the initial heating stage is to raise the temperature from room temperature to 200℃ within 10min; the second stage is to raise the temperature from 200℃ to 220℃ within 3min; After digestion is completed and cooled, take out the digestion tank, transfer the solution to a centrifuge tube to observe whether there is precipitation, then transfer the digested solution to a 100ml PP volumetric flask, dilute the solution to the scale, and shake well.

2. A digestion method for ceramic powder component detection according to claim 1, characterized in that: In the S1.1, the amplitude of the vibration grinder is 2-4 mm, the grinding frequency is 30-50 Hz, and the grinding time is 10-20 min.

3. A digestion method for ceramic powder component detection according to claim 1, characterized in that: In the S1.1, the powder particle size of the ground sample is 60-100 mesh.

4. A digestion method for detecting the composition of ceramic powders according to claim 1, characterized in that: In S1.1, the ultrasonic power for ultrasonic mixing is 60-100 W, and the ultrasonic time is 5-10 min.

5. A digestion method for ceramic powder component detection according to claim 1, characterized in that: In S1.2, the speed of gentle shaking is 10-30 times per minute.

6. A digestion method for detecting the composition of ceramic powders according to claim 1, characterized in that: In S1.2, the concentration of dilute sulfuric acid is 0.05-0.5 mol / L.

7. A digestion method for detecting the composition of ceramic powders according to claim 1, characterized in that: In S1.2, the pH value is adjusted to 6-7 by dilute sulfuric acid.

8. A digestion method for detecting the composition of ceramic powders according to claim 1, characterized in that: In the S1.2, the stirring speed is 200-400 rpm, and the stirring time is 5-15 min.

9. A digestion method for detecting the composition of ceramic powders according to claim 1, characterized in that: In S1.3, the temperature is raised to 200°C and maintained for 5 minutes in the initial heating stage, and the temperature is raised to 220°C and maintained for 30 minutes in the second heating stage.

10. A digestion method for detecting the composition of ceramic powders according to claim 1, characterized in that: In the S1.3, the oscillation frequency is 150-200 times / minute, the amplitude is 2-3 cm, and the oscillation time is 1-3 min.