Method for detecting impurity elements in tantalum pentoxide

Abstract

The invention relates to the technical field of impurities in metal oxides, in particular to a method for detecting impurity elements in tantalum pentoxide, which comprises the following steps: adding quantitative dried tantalum pentoxide powder into a polytetrafluoroethylene digestion bottle; adding hydrofluoric acid and nitric acid, sealing the bottle body, putting the polytetrafluoroethylene digestion bottle into holes of a porous electric heating plate, and carrying out gradient heating to dissolve the tantalum pentoxide powder, so as to obtain a fluorine tantalum salt solution; the fluorine complex tantalum salt solution is transferred into a separating funnel, sulfuric acid is added for oscillation, then an extracting agent is added for oscillation and standing, after complete phase separation, a water phase solution and an organic phase solution are obtained, the water phase solution mainly comprises impurity elements, and the organic phase solution mainly comprises a tantalum matrix; the water-phase solution is collected into a plastic volumetric flask by rotating a cock of the separating funnel; taking a preset amount of water phase solution from the plastic volumetric flask as a to-be-detected sample, and detecting the content of impurity elements in the to-be-detected sample by using an inductively coupled plasma emission spectrometer.

Description

Technical Field

[0001] The present invention relates to the technical field of impurity measurement in metal oxides, and in particular to a method for detecting impurity elements in tantalum pentoxide. Background Art

[0002] Tantalum pentoxide, as a high-temperature structural and functional material, is widely used in acoustic wave filters, thermoelectric infrared sensors, optoelectronic devices, and other fields. Its material properties are extremely sensitive to the content of impurities. Even trace amounts of impurities such as iron, calcium, magnesium, and zinc can significantly affect the material's physical and chemical properties and functionality, thereby reducing the performance and reliability of related products. Therefore, accurate detection of impurities in tantalum pentoxide is crucial to ensuring product quality.

[0003] In some scenarios, accurate detection of impurity elements in tantalum pentoxide requires pretreatment of the sample. This pretreatment involves dissolving the sample and separating the tantalum matrix. During the dissolution phase, conventional open-top digestion methods, due to their lengthy operation times, can easily lead to the loss of volatile elements. Furthermore, in an open environment, external contaminants can easily enter, affecting the accuracy of final impurity element detection. While alkaline fusion can effectively decompose insoluble samples, the introduction of large amounts of alkali metal salts can interfere with subsequent detection, resulting in lower accuracy for impurity element detection. During high-temperature calcination in the dry ashing method, elements such as calcium and magnesium react with the crucible material to form insoluble compounds, leading to biased test results. Matrix suppression and spectral interference from the tantalum matrix after dissolution are also key factors affecting the accuracy of impurity element detection. This is because the tantalum matrix is ​​complex and spectral overlap with impurity elements can easily lead to signal confusion and misinterpretation. Therefore, separation of the tantalum matrix is ​​necessary. During the separation phase of the tantalum matrix, a precipitant (such as Fe(OH)3) is often added to the tantalum pentoxide solution to adsorb impurities, leaving the tantalum matrix in solution and thus separating the impurity elements from the tantalum matrix. However, this method is overly dependent on the solution pH. If the solution pH is not accurate, the separation efficiency is low and the precipitant contamination may be introduced. Therefore, the above-mentioned tantalum pentoxide pretreatment method is less reliable and cannot ensure the effective dissolution of the tantalum pentoxide and the effective separation of the tantalum matrix and impurity elements in the tantalum pentoxide. Summary of the Invention

[0004] In view of this, it is necessary to provide a method for detecting impurity elements in tantalum pentoxide to determine the content of impurity elements in tantalum pentoxide.

[0005] In a first aspect, an embodiment of the present invention discloses a method for detecting impurity elements in tantalum pentoxide, comprising: taking a predetermined amount of dried tantalum pentoxide powder and adding it to a polytetrafluoroethylene digestion bottle, adding hydrofluoric acid and nitric acid to seal the bottle, placing the polytetrafluoroethylene digestion bottle in the holes of a porous electric heating plate and performing gradient heating to dissolve the tantalum pentoxide powder to obtain a fluorotantalum salt solution; transferring the fluorotantalum salt solution into a separatory funnel, adding sulfuric acid and shaking it, then adding an extractant and shaking it, and standing it, to obtain an aqueous phase solution and an organic phase solution after complete phase separation, wherein the aqueous phase solution mainly contains impurity elements and the organic phase solution mainly contains a tantalum matrix, and collecting the aqueous phase solution in a plastic volumetric flask by rotating the stopcock of the separatory funnel; taking a predetermined amount of the aqueous phase solution from the plastic volumetric flask as a sample to be detected, and detecting the content of impurity elements in the sample to be detected using an inductively coupled plasma emission spectrometer.

[0006] Optionally, after the aqueous phase solution is collected in a plastic volumetric flask by rotating the stopcock of the separating funnel, the method further comprises: after the aqueous phase solution is transferred into the digestion bottle, it is transferred to an acid removal instrument for two-stage heating to remove sulfuric acid, nitric acid and hydrofluoric acid in the aqueous phase solution; wherein, the power setting of the first stage in the two-stage heating is 500 W~800 W, the first stage is heated from 25°C to 100°C~120°C, the heating time is 5 min~15 min, the heating rate is 10°C / min~20°C / min, and the first stage is heated to volatilize sulfuric acid and decompose to bring out hydrofluoric acid and nitric acid; the power setting of the second stage is 800 W~1200 W, the second stage is heated from 100°C~120°C to 180°C~220°C, the heating time is 20 min~40 min, and the heating rate is 10°C / min~20 ℃ / min, and the second stage of heating is to ensure the rapid escape of acid gas; after the digestion bottle is cooled to room temperature, 0.5 mL~2.0 mL of nitric acid is added dropwise and transferred to a plastic volumetric flask, and deionized water is added to the volume to obtain an acid-removed impurity solution; a predetermined amount of the acid-removed impurity solution is taken from the plastic volumetric flask as the sample to be tested.

[0007] Optionally, after collecting the aqueous phase solution in a plastic volumetric flask by rotating the stopcock of the separatory funnel, the method further includes: adding sulfuric acid to the organic phase solution in the separatory funnel again to shake, then adding the extractant to shake and let it stand, after complete phase separation, rotating the stopcock of the separatory funnel again to collect the aqueous phase solution in a plastic volumetric flask, repeating 2 to 3 times for 15 minutes to 30 minutes.

[0008] Optionally, the amount of tantalum pentoxide powder added is 0.4000 g to 0.5000 g, the amount of hydrofluoric acid added is 0.5 mL to 2.0 mL, and the amount of nitric acid added is 0.5 mL to 2.0 mL.

[0009] Optionally, the heating rate of the porous heating plate is 10°C / min~30°C / min, the material is one of graphite or carbon fiber, and there are 20~30 holes on the surface of the porous heating plate, the hole diameter is 20 mm~35 mm, and the hole height is 30 mm~50 mm.

[0010] Optionally, when the number of polytetrafluoroethylene digestion bottles containing tantalum pentoxide powder on the porous heating plate is less than or equal to 6, the power used by the porous heating plate is 500 W to 800 W; when the number of polytetrafluoroethylene digestion bottles containing tantalum pentoxide powder on the porous heating plate is greater than 6, the power used by the porous heating plate is 800 W to 1200 W.

[0011] Optionally, gradient heating includes heating the porous electric heating plate from room temperature to a first temperature range and stabilizing for a first preset time. After the first preset time, the porous electric heating plate is heated from the first temperature range to a second temperature range and stabilizing for a second preset time. The first preset time is 10 s to 30 s, the second preset time is 40 min to 60 min, the first temperature range is 80℃ to 100℃, and the second temperature range is 180℃ to 200℃.

[0012] Optionally, electronic grade sulfuric acid is added in an amount of 0.5 mL to 2 mL.

[0013] Optionally, the extractant is at least one of tributyl phosphate, methyl isobutyl ketone, cyclohexanone, and 2-octanol.

[0014] Optionally, the impurity elements include iron, calcium, magnesium, and zinc. The spectral lines of iron, calcium, magnesium, and zinc detected by inductively coupled plasma emission spectrometry are: magnesium element spectrum line is 279.553 nm, iron element spectrum line is 238.204 nm, calcium element spectrum line is 393.366 nm, and zinc element spectrum line is 213.856 nm.

[0015] In the above-mentioned method for detecting impurity elements in tantalum pentoxide, the dried tantalum pentoxide powder is added to a polytetrafluoroethylene digestion bottle, hydrofluoric acid and nitric acid are added to seal the bottle, and the polytetrafluoroethylene digestion bottle is placed in the holes of a porous electric heating plate for gradient heating to dissolve the tantalum pentoxide powder. The fluorinated tantalum salt solution is transferred to a separatory funnel, sulfuric acid is added and shaken, and then an extractant is added and shaken and allowed to stand. After complete phase separation, an aqueous phase solution and an organic phase solution are obtained. The aqueous phase solution mainly contains impurity elements, and the organic phase solution mainly contains tantalum matrix. The aqueous phase solution is collected in a plastic volumetric flask by rotating the stopcock of the separatory funnel, and a predetermined amount of aqueous phase is taken from the plastic volumetric flask. The solution is used as the sample to be tested, and the content of impurity elements in the sample to be tested is detected using an inductively coupled plasma emission spectrometer. The closed digestion method will not cause the loss of volatile elements and the mixing of external contaminants. The use of nitric acid and hydrofluoric acid to dissolve tantalum pentoxide will not introduce other metal impurities, thereby avoiding interference with the content of impurity elements in tantalum pentoxide. In addition, when the content of impurity elements such as iron, calcium, magnesium, and zinc in the extracted aqueous solution is detected, the detection sensitivity and accuracy are improved, thereby achieving accuracy, reliability and repeatability of the detection results of impurity elements such as iron, calcium, magnesium, and zinc. DETAILED DESCRIPTION

[0016] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following describes in detail a method for detecting impurity elements in tantalum pentoxide according to the present invention, including its specific implementation, structure, features, and effectiveness. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0017] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0018] The following specifically describes a specific method for detecting impurity elements in tantalum pentoxide provided by the present invention.

[0019] The embodiment of the present invention discloses a method for detecting impurity elements in tantalum pentoxide, comprising the following steps: a) A fixed amount of dried tantalum pentoxide powder is added to a polytetrafluoroethylene digestion bottle. Hydrofluoric acid and nitric acid are added to seal the bottle, and the polytetrafluoroethylene digestion bottle is placed in the holes of a porous electric hot plate for gradient heating to dissolve the tantalum pentoxide powder, thereby obtaining a tantalum fluoride salt solution.

[0020] b) Transfer the tantalum fluoride salt solution into a separatory funnel, add sulfuric acid, shake, then add the extractant, shake, and let it stand. After complete phase separation, an aqueous phase solution and an organic phase solution are obtained. The aqueous phase solution mainly contains impurity elements, and the organic phase solution mainly contains tantalum matrix. The aqueous phase solution is collected in a plastic volumetric flask by rotating the stopcock of the separatory funnel.

[0021] c) A predetermined amount of aqueous solution is taken from the plastic volumetric flask as a sample to be tested, and the content of impurity elements in the sample to be tested is detected using an inductively coupled plasma optical emission spectrometer.

[0022] Specifically, the tantalum pentoxide in the embodiment of the present invention uses 5N tantalum pentoxide, which has a purity of 99.999% and a particle size range of 1 μm ~ 5 μm, so as to improve the dissolution efficiency. In the embodiment of the present invention, a quantitative amount of dried tantalum pentoxide powder is weighed and added to a polytetrafluoroethylene digestion bottle, and a quantitative amount of hydrofluoric acid and nitric acid is introduced into the polytetrafluoroethylene digestion bottle with a pipette. Specifically, the polytetrafluoroethylene digestion bottle is rotated and slowly added along the bottle wall. After observing that there is no tantalum pentoxide powder hanging on the inner wall of the polytetrafluoroethylene digestion bottle, the bottle cap is covered and the bottle body is sealed. After the bottle body is sealed, the polytetrafluoroethylene digestion bottle is placed in the hole of the porous electric hot plate, the flat electric furnace is turned on, and the program is started to heat the polytetrafluoroethylene digestion bottle in a gradient to dissolve the tantalum pentoxide powder.

[0023] Furthermore, as an optional embodiment of the present invention, the polytetrafluoroethylene digestion bottle has a height of 50 mm to 70 mm, an inner diameter of the digestion bottle of 15 mm to 30 mm, and a volume of the digestion bottle of 20 mL to 30 mL.

[0024] Furthermore, as an optional embodiment of the present invention, the amount of tantalum pentoxide powder added is 0.4000g to 0.5000g, the amount of hydrofluoric acid added is 0.5 mL to 2.0 mL, and the amount of nitric acid added is 0.5 mL to 2.0 mL. With this ratio, when the amount of tantalum pentoxide powder added is 0.4000g to 0.5000g, combined with 0.5 mL to 2.0 mL of hydrofluoric acid and 0.5 mL to 2.0 mL of nitric acid, under gradient heating conditions, it is possible to ensure that the tantalum pentoxide is completely dissolved, avoiding the residual impurity elements caused by incomplete dissolution, thereby ensuring the accuracy of the test results. In addition, the amount of hydrofluoric acid and nitric acid added is controlled within the range of 0.5 mL to 2.0 mL, respectively. Under the premise of ensuring the dissolution effect, the reaction rate can be in a more ideal state, which is neither too slow to affect the experimental efficiency nor too fast to make the reaction difficult to control, and less acid waste is generated, which is more environmentally friendly.

[0025] Furthermore, as an optional embodiment of the present invention, the heating rate of the porous heating plate is 10°C / min~30°C / min, the material is one of graphite or carbon fiber, and the surface of the porous heating plate is provided with 20~30 holes, the hole diameter is 20 mm~35 mm, and the hole height is 30 mm~50 mm.

[0026] Specifically, in this embodiment of the present invention, a polytetrafluoroethylene (PTFE) digestion bottle containing tantalum pentoxide powder can be placed in each hole, enabling batch dissolution of tantalum pentoxide powder and improving dissolution and detection efficiency. The hole diameter is 20 mm to 35 mm, slightly larger than the diameter of the PTFE digestion bottle to ensure that the PTFE digestion bottle fits within the hole. The hole height is 30 mm to 50 mm, ensuring that the portion of the PTFE digestion bottle containing hydrofluoric acid, nitric acid, and tantalum pentoxide powder is within the hole, ensuring uniform heating and accelerating dissolution efficiency. In this way, the heating rate is controlled between 10°C / min and 30°C / min. If the heating rate is too slow (less than 10°C / min), sample digestion and other processing processes will take too long, reducing experimental efficiency. On the other hand, if the heating rate is too fast (greater than 30°C / min), while it can shorten the time, it may lead to problems such as inadequate sample preparation and solution boiling. A heating rate of 10°C / min to 30°C / min effectively shortens processing time while ensuring sample quality, balancing experimental efficiency and accuracy, making it suitable for batch sample pretreatment. For example, during the digestion of tantalum pentoxide powder, rapidly increasing the temperature can cause a vigorous reaction between hydrofluoric acid and nitric acid, resulting in splashing of the solution and inaccurate determination of impurity element content in the sample. A stable heating rate, however, ensures uniform sample heating, ensuring complete dissolution of the tantalum pentoxide while maintaining a stable chemical form of the impurities in solution, providing a reliable sample foundation for subsequent testing. Furthermore, graphite and carbon fiber materials offer excellent thermal conductivity, enabling rapid and uniform heat transfer to the sample. When operating on a multi-hole hot plate, this ensures uniform heating of the sample across each hole, avoiding uneven sample processing due to local temperature variations. For example, in the digestion of tantalum pentoxide, uniform heating improves digestion efficiency, reduces detection errors caused by incomplete digestion, and ensures reliable test results. Furthermore, the surface is equipped with 20 to 30 holes, allowing for simultaneous processing of multiple samples, significantly improving experimental efficiency and meeting batch testing requirements. For example, in the detection of impurity elements in tantalum pentoxide, multiple samples can be digested simultaneously, reducing waiting time and making it particularly suitable for testing large quantities of products. The multiple holes also facilitate parallel experiments, allowing for comparison of treatment results across different samples, enhancing the scientificity and accuracy of the experiments. Furthermore, the holes, with diameters ranging from 20 mm to 35 mm and heights of 30 mm to 50 mm, are compatible with common experimental containers such as polytetrafluoroethylene (PTFE) digestion bottles. This optimal size ensures that the digestion bottles remain securely in the holes, preventing spillage of the solution due to shaking or tipping during heating, which could compromise experimental safety and results. Furthermore, this size design ensures ample space for the holes on the hot plate surface, ensuring good heat transfer to each hole while processing multiple samples, ensuring consistent sample processing results.

[0027] Furthermore, as an optional embodiment of the present invention, when the number of polytetrafluoroethylene digestion bottles containing tantalum pentoxide powder on the porous electric hot plate is less than or equal to six, the power used by the porous electric hot plate is 500 W to 800 W. When the number of polytetrafluoroethylene digestion bottles containing tantalum pentoxide powder on the porous electric hot plate is greater than six, the power used by the porous electric hot plate is 800 W to 1200 W. Thus, when the number of digestion bottles is small (less than or equal to six), using a lower power (500 W to 800 W) can avoid localized excessive temperatures caused by excessive power. At low power, the polytetrafluoroethylene digestion bottles are evenly heated, preventing uneven dissolution of tantalum pentoxide powder due to temperature differences, thereby ensuring consistent sample processing results. When the number of digestion bottles is large (greater than six), increasing the power to 800 W to 1200 W ensures that all digestion bottles receive sufficient heat and maintains a stable digestion temperature. When multiple digestion bottles are working simultaneously, they absorb a large amount of heat. If the power is insufficient, the temperature of the hot plate will drop, resulting in a slower digestion speed or even incomplete digestion. By increasing the power, heat loss can be compensated, ensuring that the tantalum pentoxide powder in each digestion bottle is fully dissolved at an appropriate temperature, meeting the needs of batch sample processing and improving experimental efficiency. Therefore, dynamically adjusting the power according to the number of digestion bottles can avoid unnecessary energy consumption. When the number of samples is small, low power can meet the digestion needs. If high power is used, a large amount of electrical energy will be converted into useless heat and dissipated into the environment, resulting in energy waste. When the number of samples increases, appropriately increasing the power can ensure the smooth progress of the digestion process and avoid extending the digestion time due to insufficient power, which in turn increases energy consumption. This on-demand power adjustment method can fully utilize energy and reduce experimental operating costs.

[0028] Furthermore, as an optional embodiment of the present invention, gradient heating includes heating the porous electric heating plate from room temperature to a first temperature range and stabilizing for a first preset time. After the first preset time, the porous electric heating plate is heated from the first temperature range to a second temperature range and stabilized for a second preset time. The first preset time is 10 s~30 s, the second preset time is 40 min~60 min, the first temperature range is 80℃~100℃, and the second temperature range is 180℃~200℃.

[0029] Specifically, in the first stage of gradient heating, the temperature is controlled between 80°C and 100°C and maintained for 10 to 30 seconds, allowing for a preliminary reaction between the sample and the acid reagent. Tantalum pentoxide powder reacts slowly with hydrofluoric acid and nitric acid at a relatively low temperature, avoiding rapid volatilization of the acid or overly vigorous reaction due to excessively high temperatures, thereby improving experimental safety. These mild conditions help the acid fully penetrate the tantalum pentoxide particles, paving the way for subsequent complete dissolution. Furthermore, the low temperature stage allows some volatile impurity elements (such as zinc) in the sample to dissolve in a relatively stable environment, reducing element loss due to sudden temperature increases and ensuring accurate detection of these elements. In the second stage, the temperature is raised to 180 to 200°C and maintained for 40 to 60 minutes, providing sufficient energy for the complete dissolution of the tantalum pentoxide. Tantalum pentoxide is a poorly soluble metal oxide that requires relatively high temperatures to fully react with the acid. Within this temperature range, the reaction rate between hydrofluoric acid and tantalum pentoxide increases significantly, rapidly decomposing the tantalum pentoxide and converting it into soluble fluorotantalate. Furthermore, the longer holding time ensures the complete reaction, preventing the residual tantalum pentoxide from remaining due to incomplete reaction. This ensures that all impurity elements in the sample are released into solution, improving detection accuracy. Furthermore, certain impurity elements (such as iron) may undergo valence state changes under different temperature and acidity conditions, and these valence changes may affect the element's behavior and results in subsequent testing. By controlling the temperature and reaction time, gradient heating provides a relatively stable chemical environment for the elements, reducing the possibility of valence state changes. This facilitates accurate subsequent detection using inductively coupled plasma (ICP) methods.

[0030] Furthermore, after the tantalum pentoxide powder is completely dissolved, a fluoride complex salt (TaF6 - 、TaF7 2- ), transfer the fluorine complex solution in the polytetrafluoroethylene digestion bottle into a separatory funnel, tantalum and hydrofluoric acid form a stable TaF6⁻ complex anion, add a certain amount of sulfuric acid, shake it, then add a certain amount of extractant, shake it for a while and let it stand. The TaF6⁻ complex anion combines with the extractant and is extracted into the organic phase, while most impurity elements (such as Fe 2 ⁺、Ca 2+ Mg 2+ 、Zn 2+ ) remains in the aqueous phase because it cannot form a stable complex. After complete phase separation, the aqueous phase contains the impurity element to be measured, and the organic phase contains the tantalum-containing matrix. By rotating the stopcock of the separatory funnel, the aqueous phase flows from the bottom of the separatory funnel into a plastic volumetric flask.

[0031] Furthermore, in order to further improve the extraction rate of the tantalum matrix, as an optional embodiment of the present invention, after the aqueous phase solution is collected in a plastic volumetric flask by rotating the stopcock of the separatory funnel, the method also includes: adding sulfuric acid to the organic phase solution in the separatory funnel again, shaking, and then adding an extractant to shake and let it stand. After complete phase separation, the stopcock of the separatory funnel is rotated again to collect the aqueous phase solution in a plastic volumetric flask, and repeating 2 to 3 times for 15 minutes to 30 minutes. In this way, it is difficult to completely transfer the impurity elements in the organic phase to the aqueous phase in a single extraction. Repeating the sulfuric acid treatment and extraction operation can gradually fully extract the impurity elements remaining in the organic phase into the aqueous phase solution. Sulfuric acid can change the acidity environment of the solution, promoting further separation of the impurity elements from the tantalum matrix. The subsequent addition of the extractant transfers the impurity elements from the organic phase to the aqueous phase again based on the difference in solubility or partition coefficient between the impurity elements and the tantalum matrix in different solvents. By repeating the operation 2-3 times, the extraction recovery rate of impurity elements can be significantly improved, ensuring that more impurity elements are enriched in the aqueous phase for detection, avoiding deviations in test results caused by impurity residues. Multiple extraction operations can effectively reduce the residual amount of impurity elements and reduce the interference of impurity elements remaining in the organic phase on the test results. If there are more impurity elements remaining in the organic phase, these residual impurities will affect the detection signal during subsequent testing, resulting in errors in the test results and failing to truly reflect the actual content of impurity elements in the tantalum pentoxide sample. After multiple extractions, the concentration of impurity elements in the aqueous solution is closer to the actual situation of the sample. Based on this, inductively coupled plasma optical emission spectrometry testing can obtain more accurate and reliable impurity element content data, providing strong support for the quality assessment of tantalum pentoxide materials.

[0032] Furthermore, as an optional embodiment of the present invention, the sulfuric acid is electronic grade and the amount added is 0.5 mL to 2 mL. In this way, electronic grade sulfuric acid is used, which has extremely high purity and extremely low impurity content. In the detection of tantalum pentoxide impurities, if ordinary sulfuric acid is used, the impurity elements such as iron, calcium, magnesium, and zinc contained therein will generate additional detection signals during the detection process, interfering with the accurate determination of the target impurity elements in the tantalum pentoxide sample. Electronic grade sulfuric acid, however, introduces almost no additional impurities and can effectively reduce the detection background signal, so that the signal detected by the inductively coupled plasma emission spectrometer more truly reflects the content of impurity elements in the tantalum pentoxide sample, thereby significantly improving the accuracy and reliability of the detection results. Electronic grade sulfuric acid added in an amount of 0.5 mL to 2 mL can accurately adjust the acidity of the solution, creating an optimal environment for the separation of impurity elements from the tantalum matrix. The appropriate acidity helps to change the existence form of impurity elements, making it easier to transfer from the organic phase to the aqueous phase. If too little sulfuric acid is added, the solution acidity will be insufficient, making it difficult for impurity elements to be released from their complex or combined state with the tantalum matrix, resulting in reduced extraction efficiency. Adding too much sulfuric acid may disrupt the balance of the extraction system, affecting the extractant's selectivity for impurity elements, and even causing some impurity elements to re-enter the organic phase. Therefore, a dosage range of 0.5mL-2mL can continuously and stably adjust the solution acidity during multiple extraction operations, ensuring efficient separation of impurity elements and effectively reducing the generation of acid mist, which is more environmentally friendly.

[0033] Furthermore, as an optional embodiment of the present invention, the specification of the separatory funnel is one of 100 mL and 250 mL.

[0034] Furthermore, as an optional embodiment of the present invention, the extraction ratio of the extracted organic phase to the aqueous phase is 1 to 3. During the extraction of the tantalum matrix into the organic phase, the ratio of 1 to 3 can enable the extractant to fully contact and complex with the tantalum ions, thereby improving the extraction rate of tantalum; and during the subsequent back-extraction of impurity elements, this ratio can ensure that the impurity elements effectively leave the organic phase and enter the aqueous phase, achieving efficient separation of the tantalum matrix and the impurity elements, reducing impurity residues, and improving the accuracy of detection. Therefore, controlling the ratio of the organic phase to the aqueous phase to 1 to 3 can achieve a more thorough separation of the tantalum matrix and the impurity elements, thereby reducing matrix interference. A large amount of tantalum matrix is ​​extracted into the organic phase, while the impurity elements are enriched in the aqueous phase, reducing the interference of the tantalum matrix in the aqueous phase on the impurity element detection signal, making the characteristic spectrum of the impurity elements clearer during ICP detection, and the detection results more accurate, which can more truly reflect the actual content of impurity elements in the tantalum pentoxide sample.

[0035] Furthermore, as an optional embodiment of the present invention, the extractant is at least one of tributyl phosphate, methyl isobutyl ketone, cyclohexanone, and 2-octanol.

[0036] Furthermore, as an optional embodiment of the present invention, the extraction rate of the tantalum matrix can reach more than 99%, and the residual rate of impurity elements in the organic phase is less than 5%.

[0037] Furthermore, as an optional embodiment of the present invention, the fluorotantalum salt solution is transferred to a separating funnel, sulfuric acid is added and shaken, and then the extractant is added and shaken, and the total shaking time is 3 min to 5 min. In this way, the total shaking time of 3 min to 5 min can make the substances in the extraction system fully diffuse and react, approaching the extraction equilibrium state. If the shaking time is too short, the extraction reaction is insufficient, the tantalum matrix is ​​not completely extracted, or the impurity elements are not thoroughly enriched; if the shaking time is too long, the established balance may be broken, and even unnecessary side reactions may be triggered. For example, certain impurity elements may undergo valence changes after prolonged shaking and in an acidic environment, affecting subsequent detection. This time setting can ensure that the extraction process is carried out efficiently and stably, so that the tantalum matrix enters the organic phase as much as possible, the impurity elements are effectively enriched in the aqueous phase, and the two are efficiently separated, impurity residues are reduced, and the accuracy of subsequent detection is improved.

[0038] Furthermore, as an optional embodiment of the present invention, the capacity of the plastic volumetric flask is 50 mL to 100 mL. Furthermore, the capacity of the plastic volumetric flask used to collect the organic phase solution is 200 mL to 500 mL.

[0039] Further, as an optional embodiment of the present invention, after collecting the aqueous phase solution in a plastic volumetric flask by rotating the stopcock of the separatory funnel, the method further includes: After the aqueous phase solution is transferred into the digestion bottle, it is transferred to the acid removal instrument for two-stage heating to remove sulfuric acid, nitric acid and hydrofluoric acid in the aqueous phase solution; wherein, the first stage of the two-stage heating is set to 500W~800W, the first stage is heated from 25℃ to 100℃~120℃, the heating time is 5 min~15 min, the heating rate is 10℃ / min~20℃ / min, the first stage is heated to volatilize sulfuric acid and decompose to bring out hydrofluoric acid and nitric acid; the second stage is set to 800W~1200W, the second stage is heated from 100℃~120℃ to 180℃~220℃, the heating time is 20 min~40 min, the heating rate is 10℃ / min~20℃ / min, the second stage is heated to ensure the rapid escape of acid gas; after the digestion bottle is cooled to room temperature, 0.5 mL~2.0 mL of nitric acid is transferred to a plastic volumetric flask and deionized water is added to make up the volume to obtain an acid-removed impurity solution; a predetermined amount of the acid-removed impurity solution is taken from the plastic volumetric flask as a sample to be tested.

[0040] Specifically, the embodiment of the present invention transfers the aqueous phase solution into a digestion bottle and then transfers it to an acid removal apparatus, wherein the acid removal apparatus can be a microwave acid removal apparatus. The embodiment of the present invention uses a two-stage heating program to remove the acid. In this two-stage heating program, the power, heating temperature, and heating time are set in sequence. After confirming that the digestion bottle is correctly installed in the acid removal apparatus and the pressure sensor is calibrated, the program is started. During the first heating stage, sulfuric acid volatilizes and decomposes, bringing out hydrofluoric acid and nitric acid. During the second heating stage, a large amount of white smoke continuously emerges, ensuring that the acid gas overflows quickly. During the second heating stage, salts precipitate at the bottom of the digestion bottle. At this time, the volume of the solution in the digestion bottle is less than 0.5 mL to 1 mL, and the digestion bottle is removed. After cooling to room temperature, 0.5 mL to 2.0 mL of nitric acid is added to the digestion bottle after cooling to room temperature. The solution is transferred to a plastic volumetric flask and dilute to volume with deionized water to obtain the impurity solution after the acid is removed. Finally, the acid removal apparatus is allowed to cool naturally to 30°C to 60°C before being turned off. In this manner, the first heating stage increases the temperature from 25°C to 100°C to 120°C at a power of 500W to 800W and a rate of 10°C / min to 20°C / min. During this process, the relatively low temperature and power allow the sulfuric acid to evaporate slowly, while the high boiling point of sulfuric acid simultaneously drives the decomposition and volatilization of hydrofluoric acid and nitric acid. This gentle heating method prevents the rapid escape of volatile impurities (such as zinc) from the sample with the acid mist due to sudden temperature increases, thereby minimizing element loss. The second heating stage, by increasing the power to 800W to 1200W and raising the temperature further to 180°C to 220°C at the same rate, accelerates the rapid escape of residual acid gas and ensures complete acid removal. This two-stage heating and step-by-step volatilization of the acid ensures effective acid removal while retaining the sample's impurities to the greatest extent possible, laying the foundation for accurate impurity element detection in subsequent analyses. In addition, during the acid removal process, acids such as hydrofluoric acid and nitric acid are highly corrosive and volatile, and improper operation can easily lead to danger. The two-stage temperature and power control of the heating method avoids violent boiling and splashing of the solution, reduces the risk of large-scale escape of acid mist, and protects the experimenters from acid mist. At the same time, the gradual heating method makes the internal pressure of the instrument change smoothly, reducing the hidden dangers of explosion or leakage caused by sudden pressure changes. After cooling to room temperature, the acid is added and the volume is constant, which avoids the violent reaction caused by the addition of nitric acid at high temperature, further ensuring the safety of the experimental operation. In addition, the use of a two-stage heating program for acid removal, evaporation of residual hydrofluoric acid, and the use of the impurity solution after acid removal as the sample to be tested can reduce corrosion to the inductively coupled plasma optical emission spectrometer and its cone, thereby extending the service life of the inductively coupled plasma optical emission spectrometer.

[0041] Furthermore, as an optional embodiment of the present invention, the airflow of the acid-removing instrument is controlled at 30 L / min to 60 L / min, and the pressure is controlled at 0.3 MPa to 0.5 MPa. In this way, the airflow of 30 L / min to 60 L / min can quickly carry away the acid mist generated during the acid-removing process, accelerate the volatilization of acids such as hydrofluoric acid and nitric acid, discharge the acid mist in time, and shorten the acid-removing time. Among them, if the airflow is too small (less than 30 L / min), the acid mist discharge speed is slow, the acid-removing efficiency is low, and the acid-removing efficiency may not be thorough; if the airflow is too large (greater than 60 L / min), the volatile impurity elements in the sample solution may be taken out together, causing deviations in the test results. The airflow of 30 L / min to 60 L / min ensures that the acid is fully volatilized while retaining the impurity elements in the sample to the greatest extent, laying the foundation for accurate detection. The pressure of 0.3 MPa to 0.5 MPa provides a stable environment for the acid-removing process. If the pressure is too low (below 0.3 MPa), the internal stability of the acid removal instrument may not be maintained, affecting the acid volatilization efficiency. If the pressure is too high (above 0.5 MPa), the sample solution may boil violently or even splash, resulting in sample loss. This pressure range allows the sample solution to maintain a moderate reaction state, avoiding splashing and contaminating the instrument due to abnormal pressure. It also prevents the loss of impurity elements in the tantalum pentoxide sample due to violent reactions, ensuring the integrity of the tantalum pentoxide sample and the reliability of the test results.

[0042] Furthermore, as an optional embodiment of the present invention, the deionized water is one of secondary deionized water and quadruple deionized water.

[0043] Furthermore, as an optional embodiment of the present invention, the impurity elements include: iron, calcium, magnesium, and zinc. The spectral lines of iron, calcium, magnesium, and zinc detected by the inductively coupled plasma emission spectrometer are: the magnesium element spectral line is 279.553 nm, the iron element spectral line is 238.204 nm, the calcium element spectral line is 393.366 nm, and the zinc element spectral line is 213.856 nm. The corresponding spectral lines of iron, calcium, magnesium, zinc, etc. in the sample to be tested are detected using the inductively coupled plasma emission spectrometer. In this way, the 279.553 nm spectral line of magnesium, in the tantalum pentoxide detection system, does not have strong interfering spectral lines of other common elements near this wavelength, and can accurately reflect the true content of magnesium; the 238.204 nm spectral line of iron also avoids the characteristic wavelengths of other elements, effectively avoiding detection errors caused by spectral overlap, ensuring that the detection signal is true and reliable, thereby improving the accuracy of iron detection, and the same applies to calcium and zinc. Furthermore, the selected spectral lines for magnesium (279.553 nm), iron (238.204 nm), calcium (393.366 nm), and zinc (213.856 nm) are less susceptible to spectral interference from the tantalum pentoxide matrix and can stably generate characteristic signals in this matrix environment. The selection of these spectral lines mitigates the influence of the matrix on the intensity and shape of the impurity element spectral lines, ensuring that the test results more accurately reflect the actual concentrations of calcium and zinc in the sample and reducing detection bias due to matrix effects.

[0044] The use of an inductively coupled plasma emission spectrometer to detect the impurity content in the sample to be tested can refer to known techniques and will not be further described in detail in the present embodiment. When the inductively coupled plasma emission spectrometer is used to detect the impurity content in the sample to be tested, the standard curve is prepared by pipetting 0.0 mL, 2.0 mL, 5.0 mL, and 10.0 mL of 10 μg / mL iron, calcium, magnesium, and zinc standard solutions, respectively, into a 200 mL volumetric flask, diluting to the scale, shaking well, and measuring on the spectrometer.

[0045] A closed digestion method combining a porous electric heating plate and a polytetrafluoroethylene digestion bottle is used to gradually decompose the tantalum pentoxide powder by gradient heating. This method has good temperature uniformity and requires less hydrofluoric acid and nitric acid. Therefore, the amount of acid mist and waste liquid generated during the digestion process is less, which is more environmentally friendly. The gradient heating method avoids splashing caused by violent reactions, improves the safety of operation, and the closed digestion method does not cause the loss of volatile elements and avoids the problem of external pollutants being mixed in. In addition, the embodiment of the present invention uses nitric acid and hydrofluoric acid to dissolve tantalum pentoxide, and does not introduce other metal impurities, thereby avoiding interference with the content of impurity elements in tantalum pentoxide. The effective dissolution of tantalum pentoxide is guaranteed. Furthermore, the use of a porous electric heating plate can also achieve efficient dissolution of batches of tantalum pentoxide powder, thereby improving the dissolution efficiency of tantalum pentoxide powder. The tantalum matrix and trace impurity elements are separated by a liquid-liquid extraction method in which sulfuric acid and an extractant cooperate with each other, and are extracted into the organic phase after being combined with the extractant, while most trace impurities (such as Fe 2 ⁺、Ca 2+ Mg 2+ 、Zn 2 + ) are retained in the aqueous phase because they cannot form a stable complex, thereby separating the tantalum matrix and the impurity elements, reducing the ionization inhibition of the tantalum matrix on impurity elements such as iron, calcium, magnesium, and zinc, and this method does not require a high pH value of the solution and will not introduce other impurities, thereby achieving effective separation of the tantalum matrix and impurity elements in tantalum pentoxide, and improving the efficiency and degree of separation of the tantalum matrix and impurity elements. In this way, the technical solution provided by the present invention can not only achieve the complete digestion of tantalum pentoxide, but also effectively eliminate the interference of the tantalum matrix on the detection of impurity elements such as iron, calcium, magnesium, and zinc, while avoiding external contamination of the sample during the processing process, ensuring the accuracy, reliability and repeatability of the detection results of impurity elements such as iron, calcium, magnesium, and zinc, and when detecting the content of impurity elements such as iron, calcium, magnesium, and zinc in the extracted aqueous solution, the detection sensitivity and accuracy are improved.

[0046] In order to further understand the present invention, the method for detecting impurity elements in tantalum pentoxide provided by the present invention is described in detail below with reference to the examples. The protection scope of the present invention is not limited by the following examples. Example 1

[0047] 0.4843 g of dried tantalum pentoxide powder was added to a polytetrafluoroethylene digestion bottle with a height of 70 mm, an inner diameter of 20 mm, and a volume of 20 mL. 2.0 mL of hydrofluoric acid and 2.0 mL of nitric acid were added to seal the bottle, and the polytetrafluoroethylene digestion bottle was placed in the holes of a porous hot plate. The temperature of the porous hot plate was increased from room temperature to 100°C at a heating rate of 30°C / min and stabilized for 30 s. The temperature of the porous hot plate was then increased from 100°C to 200°C at a heating rate of 30°C / min and stabilized for 60 min to dissolve the tantalum pentoxide powder and obtain a fluorotantalum salt solution.

[0048] The fluorotantalum salt solution in step 1) was transferred to a 100 mL separatory funnel, 0.5 mL of electronic grade sulfuric acid was added, and the mixture was shaken for 3 minutes. Then, tributyl phosphate, an extractant, was added, and the mixture was shaken for 2 minutes and allowed to stand. After complete phase separation, an aqueous phase solution and an organic phase solution were obtained. The aqueous phase solution mainly contained impurity elements such as iron, calcium, magnesium, and zinc, and the organic phase solution mainly contained a tantalum matrix. The aqueous phase solution was collected in a 50 mL plastic volumetric flask by rotating the stopcock of the separatory funnel.

[0049] 3) Add 0.5 mL of electronic-grade sulfuric acid to the organic phase solution in the separatory funnel from step 2) and shake for 3 minutes. Then add tributyl phosphate and shake for 2 minutes. Shake and let stand. After complete phase separation, rotate the stopcock of the separatory funnel again to collect the aqueous phase solution in a 50 mL plastic volumetric flask. Repeat 2–3 times for 15 minutes.

[0050] 4) Transfer the aqueous solution from the 50 mL plastic volumetric flask in step 3) to the digestion flask and transfer it to an acid remover for a two-stage heating process to remove sulfuric acid, nitric acid, and hydrofluoric acid. The acid remover's airflow was controlled at 60 L / min and the pressure at 0.5 MPa. The power of the first stage of the two-stage heating process was set at 800 W, with the temperature rising from 25°C to 120°C over 10 minutes at a rate of 10°C / min. The power of the second stage was set at 1000 W, with the temperature rising from 120°C to 220°C over 30 minutes at a rate of 15°C / min.

[0051] 5) After the digestion bottle in step 4) cools to room temperature, add 2.0 mL of nitric acid dropwise and transfer to a 50 mL plastic volumetric flask. Add secondary deionized water to the volume to obtain an acid-removed impurity solution.

[0052] 6) The acid remover will naturally cool down to 50℃ and can be turned off.

[0053] 7) Take 1 mL of the impurity solution after acid removal from the 50 mL plastic volumetric flask in step 5) as the test sample. Analyze the impurity elements iron, calcium, magnesium, and zinc in the sample using inductively coupled plasma optical emission spectrometry. The spectra of iron, calcium, magnesium, and zinc detected by inductively coupled plasma optical emission spectrometry are: magnesium at 279.553 nm, iron at 238.204 nm, calcium at 393.366 nm, and zinc at 213.856 nm.

[0054] After testing, the extraction rate of tantalum can reach 99.8%, the residual iron element is 3%, the residual calcium element is 2%, the residual magnesium element is 1%, and the residual zinc element is 1%. The accuracy of the inductively coupled plasma emission spectrometer in detecting the impurity elements iron, calcium, magnesium and zinc in the sample to be tested reaches 99.8%. Example 2

[0055] 1) 0.3000 g of dried tantalum pentoxide powder was added to a 20 mL polytetrafluoroethylene digestion bottle with a height of 50 mm, an inner diameter of 25 mm, and a volume of 20 mL. 1.5 mL of hydrofluoric acid and 1.5 mL of nitric acid were added to seal the bottle. The polytetrafluoroethylene digestion bottle was placed in the holes of a porous hot plate. The temperature of the hot plate was increased from room temperature to 80°C at a heating rate of 20°C / min and stabilized for 20 s. The temperature was then increased from 80°C to 180°C at a heating rate of 20°C / min and stabilized for 50 min to dissolve the tantalum pentoxide powder and obtain a tantalum fluoride salt solution.

[0056] 2) The fluorotantalum salt solution in step 1) was transferred to a 100 mL separatory funnel, 0.5 mL of electronic grade sulfuric acid was added, and the mixture was shaken for 3 minutes. Then, tributyl phosphate was added as an extractant and the mixture was shaken for 2 minutes and allowed to stand. After complete phase separation, an aqueous phase solution and an organic phase solution were obtained. The aqueous phase solution mainly contained impurity elements such as iron, calcium, magnesium, and zinc, and the organic phase solution mainly contained a tantalum matrix. The aqueous phase solution was collected in a 50 mL plastic volumetric flask by rotating the stopcock of the separatory funnel.

[0057] 3) Add 0.5 mL of electronic-grade sulfuric acid to the organic phase solution in the separatory funnel from step 2) and shake for 3 minutes. Then add tributyl phosphate and shake for 2 minutes. Shake and let stand. After complete phase separation, rotate the stopcock of the separatory funnel again to collect the aqueous phase solution in a 50 mL plastic volumetric flask. Repeat 2–3 times for 15 minutes.

[0058] 4) Transfer the aqueous solution from the 50 mL plastic volumetric flask in step 3) to the digestion flask and transfer it to an acid remover for a two-stage heating process to remove sulfuric acid, nitric acid, and hydrofluoric acid. The acid remover's airflow was controlled at 50 L / min and the pressure at 0.4 MPa. The first stage of the two-stage heating process was set to 700 W, with the temperature increasing from 25°C to 100°C over 10 minutes at a rate of 15°C / min. The second stage was set to 900 W, with the temperature increasing from 100°C to 200°C over 20 minutes at a rate of 20°C / min.

[0059] 5) After the digestion bottle in step 4) cools to room temperature, add 1.0 mL of nitric acid dropwise and transfer to a 50 mL plastic volumetric flask. Add secondary deionized water to the volume to obtain an acid-removed impurity solution.

[0060] 6) The acid remover will naturally cool down to 30℃ and can be turned off.

[0061] 7) Take 1 mL of the impurity solution after acid removal from the 50 mL plastic volumetric flask in step 5) as the test sample. Analyze the impurity elements iron, calcium, magnesium, and zinc in the sample using inductively coupled plasma optical emission spectrometry. The spectra of iron, calcium, magnesium, and zinc detected by inductively coupled plasma optical emission spectrometry are: magnesium at 279.553 nm, iron at 238.204 nm, calcium at 393.366 nm, and zinc at 213.856 nm.

[0062] After testing, the extraction rate of tantalum can reach 99.7%, the residual iron content is 4%, the residual calcium content is 3%, the residual magnesium content is 3%, and the residual zinc content is 2%. The accuracy of the inductively coupled plasma emission spectrometer in detecting the impurity elements iron, calcium, magnesium and zinc in the sample to be tested reaches 99.8%.

[0063] It should be noted that the order of the above embodiments of the present invention is for description only and does not represent the superiority or inferiority of the embodiments. In some embodiments, multi-tasking and parallel processing are also possible or may be advantageous.

[0064] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for detecting impurity elements in tantalum pentoxide, characterized in that: The method for detecting impurity elements in tantalum pentoxide comprises: A quantitative amount of dried tantalum pentoxide powder is added to a polytetrafluoroethylene digestion bottle, hydrofluoric acid and nitric acid are added to seal the bottle, and the polytetrafluoroethylene digestion bottle is placed in the holes of a porous electric hot plate for gradient heating to dissolve the tantalum pentoxide powder, thereby obtaining a tantalum fluoride salt solution; The fluorotantalum salt solution is transferred to a separatory funnel, sulfuric acid is added and shaken, and then an extractant is added and shaken and allowed to stand. After complete phase separation, an aqueous phase solution and an organic phase solution are obtained. The aqueous phase solution mainly contains impurity elements, and the organic phase solution mainly contains tantalum matrix. The aqueous phase solution is collected in a plastic volumetric flask by rotating the stopcock of the separatory funnel; A predetermined amount of aqueous solution is taken from the plastic volumetric flask as a sample to be detected, and the content of impurity elements in the sample to be detected is detected using an inductively coupled plasma emission spectrometer.

2. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: After collecting the aqueous phase solution in a plastic volumetric flask by rotating the stopcock of the separatory funnel, the method further comprises: After the aqueous phase solution is transferred into the digestion bottle, it is transferred to the acid removal instrument for two-stage heating to remove sulfuric acid, nitric acid and hydrofluoric acid in the aqueous phase solution; wherein, the power setting of the first stage of the two-stage heating is 500 W~800 W, the first stage is heated from 25°C to 100°C~120°C, the heating time is 5min~15min, the heating rate is 10°C / min~20°C / min, and the first stage is heated to volatilize sulfuric acid and decompose to bring out hydrofluoric acid and nitric acid; the power setting of the second stage is 800 W~1200 W, the second stage is heated from 100°C~120°C to 180°C~220°C, the heating time is 20 min~40 min, the heating rate is 10°C / min~20°C / min, and the second stage is heated to ensure rapid escape of acid gas; After the digestion bottle has cooled to room temperature, add 0.5 mL to 2.0 mL of nitric acid dropwise and transfer to a plastic volumetric flask. Add deionized water to the volume to obtain an acid-removed impurity solution. A predetermined amount of the impurity solution after removing the acid is taken from the plastic volumetric flask as a sample to be tested.

3. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: After collecting the aqueous phase solution in a plastic volumetric flask by rotating the stopcock of the separatory funnel, the method further comprises: Add sulfuric acid to the organic phase solution in the separatory funnel again, shake it, then add the extractant, shake it and let it stand. After complete phase separation, rotate the stopcock of the separatory funnel again to collect the aqueous phase solution in the plastic volumetric flask. Repeat 2 to 3 times for 15 min to 30 min.

4. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: The amount of tantalum pentoxide powder added is 0.4000 g to 0.5000 g, the amount of hydrofluoric acid added is 0.5 mL to 2.0 mL, and the amount of nitric acid added is 0.5 mL to 2.0 mL.

5. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: The heating rate of the porous electric heating plate is 10℃ / min~30℃ / min. The material is one of graphite or carbon fiber. There are 20~30 holes on the surface of the porous electric heating plate. The hole diameter is 20 mm~35 mm and the hole height is 30 mm~50 mm.

6. The method for detecting impurity elements in tantalum pentoxide according to claim 5, characterized in that: When the number of polytetrafluoroethylene digestion bottles containing tantalum pentoxide powder on the porous electric heating plate is less than or equal to 6, the power used by the porous electric heating plate is 500 W to 800 W. When the number of polytetrafluoroethylene digestion bottles containing tantalum pentoxide powder on the porous electric heating plate is greater than 6, the power used by the porous electric heating plate is 800 W to 1200 W.

7. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: The gradient heating includes heating the porous electric heating plate from room temperature to a first temperature range and stabilizing for a first preset time. After the first preset time, the porous electric heating plate is heated from the first temperature range to a second temperature range and stabilized for a second preset time. The first preset time is 10 s to 30 s, the second preset time is 40 min to 60 min, the first temperature range is 80°C to 100°C, and the second temperature range is 180°C to 200°C.

8. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: The sulfuric acid is electronic grade and the amount added is 0.5 mL~2 mL.

9. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: The extractant is at least one of tributyl phosphate, methyl isobutyl ketone, cyclohexanone and 2-octanol.

10. The method for detecting impurity elements in tantalum pentoxide according to claim 1, characterized in that: The impurity elements include iron, calcium, magnesium, and zinc. The spectral lines of iron, calcium, magnesium, and zinc detected by the inductively coupled plasma emission spectrometer are: the magnesium element spectrum line is 279.553 nm, the iron element spectrum line is 238.204 nm, the calcium element spectrum line is 393.366 nm, and the zinc element spectrum line is 213.856 nm.