Method for determining content of harmful elements in sodium pyroantimonate sample

Abstract

The invention relates to the technical field of detection, particularly provides a method for determining the content of harmful elements in a sodium pyroantimonate sample, and aims to solve the problems of low efficiency and poor precision when the content of the harmful elements in the sodium pyroantimonate sample is determined. In order to achieve the purpose, the determination method comprises the following steps: weighing a sodium pyroantimonate sample with a first preset mass, and putting the sodium pyroantimonate sample into a digestion container; adding oxidizing acid with a first preset volume into the digestion container, and preheating the digestion container; adding a second predetermined volume of hydrochloric acid into the digestion container, and reheating the digestion container to completely digest the sodium pyroantimonate sample; fixing the volume of the completely digested sodium pyroantimonate sample to obtain a test solution; and determining the content of harmful elements in the test solution. According to the method, low-valence unstable harmful elements can be heated and oxidized into high-valence harmful elements by using the oxidizing acid, so that the accuracy of a determination result is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, and particularly provides a method for determining the content of harmful elements in a sodium pyroantimonate sample. BACKGROUND

[0002] Sodium pyroantimonate is an inorganic compound composed of sodium ions and antimonate ions. It is a white crystalline or powdery solid at room temperature, with a high melting point (about 630°C) and good thermal stability. Sodium pyroantimonate can be used as a flame retardant and stabilizer, and is widely used in the flame retardation of materials such as plastics, textiles, and rubbers. It can also be used as a clarifying agent and decolorizing agent for the processing of high-grade glass products (such as picture tubes and optical glass), to improve the ultraviolet resistance and heat resistance of the glass.

[0003] Currently, composite clarifiers are commonly used in the photovoltaic industry, i.e., sodium pyroantimonate is co-prepared with other compounds. As a result, sodium pyroantimonate samples often contain a variety of other elements, or sodium pyroantimonate products prepared using multiple raw material sources and different process routes often contain other impurities. For example, sodium pyroantimonate may contain trace amounts of harmful elements such as arsenic, lead, and cadmium. Long-term exposure to sodium pyroantimonate products with excessive harmful elements can cause harm to the human body, such as irritation of the respiratory tract, eyes, and skin, causing symptoms such as coughing and difficulty breathing, increasing the risk of lung cancer and skin cancer, and the like. Therefore, how to quickly and accurately determine the content of harmful elements in sodium pyroantimonate is of great significance to harmful source control, product quality monitoring, and commercial trade. SUMMARY

[0004] The present application aims to solve or improve the above technical problems to some extent, i.e., the technical problem of lacking a method for quickly and accurately determining the content of harmful elements in sodium pyroantimonate in the prior art.

[0005] In a first aspect, the present application provides a method for determining the content of harmful elements in a sodium pyroantimonate sample. The method comprises: weighing a first predetermined mass of the sodium pyroantimonate sample and placing it in a digestion vessel; adding a first predetermined volume of an oxidizing acid to the digestion vessel and pre-heating the digestion vessel; adding a second predetermined volume of hydrochloric acid to the digestion vessel and re-heating the digestion vessel to completely digest the sodium pyroantimonate sample; performing constant volume on the completely digested sodium pyroantimonate sample to obtain a test solution; and determining the content of harmful elements in the test solution.

[0006] The skilled in the art can understand that the method for determining the content of harmful elements in the sodium pyroantimonate sample of the present application comprises the following steps: weighing a first predetermined mass of the sodium pyroantimonate sample and placing it in a digestion vessel; then, adding a first predetermined volume of oxidizing acid in the digestion vessel and pre-heating the digestion vessel; then, adding a second predetermined volume of hydrochloric acid in the digestion vessel and re-heating the digestion vessel, so as to completely digest the sodium pyroantimonate sample; then, constant volume of the completely digested sodium pyroantimonate sample to obtain a test solution; finally, determining the content of harmful elements in the test solution to determine the content of harmful elements in the sodium pyroantimonate sample. In the case of using the above technical solution, the present application can use oxidizing acid to heat and oxidize the unstable harmful elements in low valence state into high valence state, prevent the decomposition and volatilization loss of harmful elements in low valence state during the digestion process, and ensure the accuracy of the determination result. In addition, the present application can also use hydrochloric acid to quickly and efficiently digest the sodium pyroantimonate sample, and ensure the test efficiency.

[0007] In the preferred technical solution of the above method for determining the content of harmful elements in the sodium pyroantimonate sample, a second predetermined mass of tartaric acid is added to the digestion vessel at the same time as the first predetermined volume of oxidizing acid is added to the digestion vessel. Tartaric acid can act as a complexing agent to form stable complexes with part of the harmful elements in the sodium pyroantimonate sample, which helps to better dissolve the sample during the digestion process, improves the digestion efficiency, and makes the harmful elements more fully released into the solution, laying a foundation for more accurate determination of the content of harmful elements subsequently.

[0008] In the preferred technical solution of the above method for determining the content of harmful elements in the sodium pyroantimonate sample, the ratio between the first predetermined mass and the second predetermined mass ranges from 0.1 to 5. By reasonably controlling the mass ratio of sodium pyroantimonate sample to tartaric acid, it can ensure that the two play a better synergistic effect during the digestion process.

[0009] In the preferred technical solution of the above method for determining the content of harmful elements in the sodium pyroantimonate sample, the oxidizing acid includes nitric acid or perchloric acid. Both nitric acid and perchloric acid have strong oxidizing properties, which can effectively oxidize the harmful elements in the sodium pyroantimonate sample, making them quickly and efficiently released from the sample, and can reduce the test error caused by the solubility and stability of low valence substances.

[0010] In the preferred technical solution of the above method for determining the content of harmful elements in the sodium pyroantimonate sample, the ratio between the first predetermined volume and the second predetermined volume ranges from 0.1 to 5. By reasonably controlling the volume ratio of oxidizing acid and hydrochloric acid, it helps to adjust the acidity and reaction environment of the digestion system, ensures the digestion efficiency, reduces the occurrence of side reactions, and thus more effectively extracts harmful elements into the solution.

[0011] In the preferred embodiment of the method for determining the content of harmful elements in the above-mentioned sodium pyroantimonate sample, the harmful elements include one or more of arsenic, lead, cadmium, chromium, nickel, and bismuth. This setting clearly identifies the types of harmful elements to be measured, facilitating a comprehensive assessment of the quality and safety of the sodium pyroantimonate sample.

[0012] In the preferred embodiment of the method for determining the content of harmful elements in the aforementioned sodium pyroantimonate sample, the digestion container is an Erlenmeyer flask or a steel volumetric flask. Erlenmeyer flasks possess good heat resistance and chemical stability, capable of withstanding the high temperatures and chemical corrosion that may occur during digestion. Furthermore, their shape facilitates shaking and mixing of solutions, aiding the digestion reaction. Additionally, steel volumetric flasks (or "dual-purpose flasks") are similar in shape to flat-bottomed flasks, with a ring engraved on their necks. They offer advantages in high-temperature resistance and corrosion resistance, making them suitable containers for heating, dissolving, and diluting for measurement.

[0013] In the preferred embodiment of the method for determining the content of harmful elements in the sodium pyroantimonate sample, the temperature ranges for preheating and reheating are 150℃-230℃, respectively. Setting the preheating and reheating temperatures to 150℃-230℃ ensures that the oxidizing acid and hydrochloric acid, among other digestion reagents, fully exert their decomposition effects, effectively releasing the harmful elements. It also avoids excessively high temperatures that could lead to reagent volatilization or unnecessary side reactions, thus ensuring the stability and controllability of the digestion process.

[0014] In the preferred embodiment of the method for determining the content of harmful elements in the sodium pyroantimonate sample, the preheating time is 2-12 minutes. Specifying a preheating time range ensures that the oxidizing acid and the sodium pyroantimonate sample have a relatively stable and suitable reaction time at the beginning of the reaction, preparing for subsequent reheating and complete digestion. This avoids insufficient oxidation reaction of the oxidizing acid and sodium pyroantimonate sample due to an excessively short preheating time, and also avoids energy waste and potential reagent loss due to an excessively long preheating time.

[0015] In the preferred technical scheme of the above-mentioned method for determining the content of harmful elements in sodium pyroantimonate samples, an inductively coupled plasma atomic emission spectrometer (ICP-AES), an atomic absorption spectrophotometer (AAS), or an atomic fluorescence spectrophotometer (AFS) is used to determine the content of harmful elements in the test solution. ICP-AES has advantages such as simultaneous multi-element determination, high sensitivity, and a wide linear range, enabling rapid and accurate determination of the content of multiple harmful elements in the test solution. AAS has high selectivity and sensitivity for specific elements, making it suitable for determining the content of single or a few harmful elements. AFS has unique advantages for certain harmful elements (such as arsenic), exhibiting high sensitivity and low interference. By selecting appropriate methods according to different testing needs, the accuracy and efficiency of harmful element content determination can be improved. Attached Figure Description

[0016] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which: Figure 1 This is a schematic flowchart of the method for determining the content of harmful elements in sodium pyroantimonate samples according to the present invention. Figure 2 This is a schematic flowchart of the first embodiment of the method for determining the content of harmful elements in sodium pyroantimonate samples of the present invention; Figure 3 This is a schematic flowchart of the second embodiment of the method for determining the content of harmful elements in sodium pyroantimonate samples of the present invention. Detailed Implementation

[0017] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0018] It should be noted that in the description of this invention, terms such as "upper," "lower," "left," "right," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] To address or improve, to some extent, the lack of a rapid and accurate method for determining the content of harmful elements in sodium pyroantimonate, this invention provides a method for determining the content of harmful elements in a sodium pyroantimonate sample. The method includes: weighing a first predetermined mass of sodium pyroantimonate sample and placing it in a digestion container (step S1); adding a first predetermined volume of oxidizing acid to the digestion container and preheating the container (step S2); adding a second predetermined volume of hydrochloric acid to the digestion container and reheating the container to completely digest the sodium pyroantimonate sample (step S3); adjusting the volume of the completely digested sodium pyroantimonate sample to obtain a test solution (step S4); and determining the content of harmful elements in the test solution (step S5).

[0021] Figure 1 This is a schematic flowchart of the method for determining the content of harmful elements in sodium pyroantimonate samples according to the present invention. Figure 1 As shown, in one or more embodiments, after the method for determining the content of harmful elements in a sodium pyroantimonate sample of the present invention begins, step S1 is first executed, that is, a first predetermined mass of sodium pyroantimonate sample is weighed and placed in a digestion container. Next, the method executes step S2, that is, a first predetermined volume of oxidizing acid is added to the digestion container, and the digestion container is preheated. Then, the method proceeds to step S3, a second predetermined volume of hydrochloric acid is added to the digestion container, and the digestion container is reheated to completely digest the sodium pyroantimonate sample. Next, the method continues to execute step S4, that is, the completely digested sodium pyroantimonate sample is brought to a final volume to obtain a test solution. Finally, the method executes step S5 to determine the content of harmful elements in the test solution. Through the above setup, the present invention can utilize oxidizing acid to heat and oxidize low-valence unstable harmful elements to high-valence states, preventing the decomposition and volatilization loss of low-valence harmful elements during digestion, and ensuring the accuracy of the measurement results. In addition, the present invention can also utilize hydrochloric acid to rapidly and efficiently digest the sodium pyroantimonate sample, ensuring testing efficiency.

[0022] Figure 2 This is a schematic flowchart of the first embodiment of the method for determining the content of harmful elements in sodium pyroantimonate samples according to the present invention. Figure 2 As shown, in one or more embodiments, after the method for determining the content of harmful elements in a sodium pyroantimonate sample of the present invention begins, step S11 is first executed, that is, weighing a first predetermined mass of sodium pyroantimonate sample. In one or more embodiments, the first predetermined mass is 0.1 g. Alternatively, the first predetermined mass can also be set to other suitable masses more or less than 0.1 g, such as 0.08 g, 0.12 g, etc. The weighing accuracy can be adjusted according to actual needs, for example, accurate to 0.00001 g. Next, the determination method executes step S12, that is, placing the sodium pyroantimonate sample in a digestion container. In one or more embodiments, the digestion container is an Erlenmeyer flask. Erlenmeyer flasks have good heat resistance and chemical stability, and can withstand the high temperature and chemical corrosion that may occur during digestion. At the same time, their shape facilitates shaking and mixing of solutions, which helps the digestion reaction to proceed. Alternatively, the digestion container can also be a steel volumetric flask or other suitable container. Steel volumetric flasks (or "dual-purpose flasks") resemble flat-bottomed flasks in shape, with a ring engraved on their necks. They possess advantages such as high-temperature resistance and corrosion resistance, making them suitable containers for heating, dissolving, and diluting. Furthermore, the capacity of the digestion container can be adjusted according to actual needs, such as 100mL, 150mL, or 200mL.

[0023] See also Figure 2In one or more embodiments, after step S12 is completed, the determination method proceeds to step S21, which involves adding a first predetermined volume of oxidizing acid to the digestion container. The oxidizing acid can be, but is not limited to, nitric acid and perchloric acid. It should be noted that both nitric acid and perchloric acid have strong oxidizing properties and can effectively oxidize and decompose harmful elements in the sodium pyroantimonate sample, allowing them to be released rapidly and efficiently from the sample. More importantly, the oxidizing acid can react with unstable low-valence harmful elements to convert them to high-valence states, preventing the decomposition and volatilization loss of low-valence harmful elements during digestion and ensuring the accuracy of the determination results. Preferably, the purity of nitric acid or perchloric acid is not lower than analytical grade to avoid impurities affecting the accuracy of the determination results. Additionally, sulfuric acid can be excluded when selecting the oxidizing acid to prevent sulfuric acid from reacting with some elements (e.g., lead) in the sodium pyroantimonate sample to produce precipitation, which would significantly reduce the accuracy of the determination results. In one or more embodiments, the first predetermined volume is 5 mL. Alternatively, the first predetermined volume can also be set to other suitable volumes, such as 4 mL, 6 mL, etc., which may be more or less than 5 mL.

[0024] In one or more embodiments, before performing step S21, the determination method may further perform the following step: wetting the sodium pyroantimonate sample with deionized water. After wetting with deionized water, the surface of the sodium pyroantimonate sample becomes moist. When a digestion reagent (such as an oxidizing acid) is added, the digestion reagent can be more uniformly and quickly dispersed on the sample surface, increasing the contact area between the digestion reagent and the sample. Wetting the sample with deionized water also provides a relatively uniform aqueous environment for the digestion reaction, allowing harmful elements to be released into the solution more effectively. In addition, when a dry sodium pyroantimonate sample is suddenly added to the digestion reagent, the sample may splash out due to violent local reactions, causing sample loss and affecting the accuracy of the determination results. Wetting the sample with deionized water can buffer the violent reaction between the digestion reagent and the sample, reduce the possibility of sample splashing, ensure the integrity of the sample, and pre-disperse the sample, promoting sufficient contact between the sample particles and the digestion reagent.

[0025] See also Figure 2In one or more embodiments, after step S21 is completed, the determination method proceeds to step S22, which involves preheating the digestion vessel. Preheating allows the oxidizing acid and sodium pyroantimonate sample to undergo a rapid and efficient oxidation reaction. In one or more embodiments, the preheating temperature range is 150℃-230℃, such as 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, etc. By controlling a suitable temperature range, it is possible to ensure that the oxidizing acid fully exerts its decomposition effect, effectively releasing harmful elements, while avoiding excessively high temperatures that could lead to reagent volatilization or unnecessary side reactions, thus ensuring the stability and controllability of the digestion process. In one or more embodiments, the preheating time is 2min-12min, such as 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, etc. By controlling the appropriate preheating time range, it is possible to ensure that the oxidizing acid and sodium pyroantimonate samples have a relatively stable and suitable reaction time in the initial reaction stage, which prepares them for subsequent reheating and complete digestion. This avoids insufficient oxidation reaction of the oxidizing acid and sodium pyroantimonate samples due to too short a preheating time, and also avoids energy waste and possible reagent loss due to too long a time.

[0026] See also Figure 2 In one or more embodiments, after step S22 is completed, the determination method proceeds to step S31, which involves adding a second predetermined volume of hydrochloric acid into the digestion container. The addition of hydrochloric acid not only enhances the solubility of oxidizing acids and provides stable acidity, maintaining the acidic environment of the digestion system, but also forms stable complexes with some harmful elements, preventing them from reacting with other substances to form precipitates or adsorbing onto the inner wall of the digestion container, thus ensuring the accuracy of the determination results. Preferably, the purity of the hydrochloric acid is not lower than analytical grade to avoid impurities affecting the accuracy of the determination results. In one or more embodiments, the ratio between the first predetermined volume and the second predetermined volume ranges from 0.1 to 5. Preferably, the ratio between the first predetermined volume and the second predetermined volume ranges from 1 to 3. Further, the ratio between the first predetermined volume and the second predetermined volume is 2. For example, the first predetermined volume is 5 mL, and the second predetermined volume is 2.5 mL.

[0027] See also Figure 2In one or more embodiments, after step 31 is completed, the determination method proceeds to step S32, which involves reheating the digestion vessel to completely digest the sodium pyroantimonate sample. The reheating setting allows the digestion reagents (including oxidizing acids and hydrochloric acid) and the sodium pyroantimonate sample to react rapidly and efficiently. In one or more embodiments, the reheating temperature range is 150℃-230℃, for example, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, etc. It should be noted that the reheating time can be adjusted according to actual needs, such as 10 min, 15 min, 20 min, etc., as long as the complete digestion of the sodium pyroantimonate sample is ensured.

[0028] See also Figure 2 In one or more embodiments, after step 32 is completed, the assay method performs step S41, which involves adjusting the volume of the completely digested sodium pyroantimonate sample to obtain a test solution. The adjusted volume can be 100 mL, 150 mL, 200 mL, or other suitable volumes.

[0029] In one or more embodiments, before performing step S41, the determination method further performs the following step: cooling the digestion container to room temperature. This not only avoids the digestion container from breaking due to sudden exposure to a cold environment or external force, reducing the risk of burns to operators from high temperatures, but also prevents the chemical reaction from continuing, ensures the accuracy of volume measurement, and reduces the impact of high temperatures on solution volume.

[0030] See also Figure 2 In one or more embodiments, after step S41 is completed, the determination method proceeds to step S51, that is, determining the content of harmful elements in the test solution. Harmful elements can be one or more of arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni), and bismuth (Bi). In one or more embodiments, inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to determine the content of harmful elements in the test solution. ICP-AES has advantages such as simultaneous multi-element determination, high sensitivity, and wide linear range, enabling rapid and accurate determination of the content of multiple harmful elements in the test solution. Alternatively, the determination method can also use atomic absorption spectrophotometer, atomic fluorescence spectrophotometer, or other suitable testing equipment to determine the content of harmful elements in the test solution.

[0031] Figure 3 This is a schematic flowchart of the second embodiment of the method for determining the content of harmful elements in sodium pyroantimonate samples of the present invention. Figure 3As shown, in one or more embodiments, after the method for determining the content of harmful elements in a sodium pyroantimonate sample of the present invention begins, the method first performs step S11, that is, weighing a first predetermined mass of sodium pyroantimonate sample. Next, the method performs step S12, that is, placing the sodium pyroantimonate sample in a digestion container. Then, the method performs step S211, that is, adding a first predetermined volume of oxidizing acid to the digestion container. Next, the method further performs step S212, that is, adding a second predetermined mass of tartaric acid to the digestion container. Tartaric acid can act as a complexing agent, forming stable complexes with some of the harmful elements in the sodium pyroantimonate sample, which helps to better dissolve the sample during digestion, improves digestion efficiency, and allows the harmful elements to be released more fully into the solution, laying the foundation for more accurate subsequent determination of the harmful element content. In one or more embodiments, the ratio between the first predetermined mass and the second predetermined mass ranges from 0.1 to 5. Preferably, the ratio between the first predetermined mass and the second predetermined mass ranges from 1 to 3. Further, the ratio between the first predetermined mass and the second predetermined mass is 1. For example, the first predetermined mass is 0.1g, and the second predetermined mass is also 0.1g. Preferably, the purity of tartaric acid is not lower than analytical grade to avoid impurities affecting the accuracy of the determination results.

[0032] Regarding steps S211 and S212, it should be noted that although this invention describes executing step S211 first and then step S212, this is merely an example. Without departing from the basic principles of this invention, those skilled in the art can arbitrarily adjust the execution order of steps S211 and S212 as needed, for example, executing step S212 first and then step S211, or executing both simultaneously. The adjusted solutions are equivalent to the technical solutions described in this invention and therefore will also fall within the protection scope of this invention.

[0033] It should be noted that the parts not mentioned in the second embodiment can be configured the same as in the first embodiment, and will not be repeated here.

[0034] The following describes in detail the operational steps of the method for determining the content of harmful elements in sodium pyroantimonate samples according to the present invention, with reference to specific embodiments. Example 1 Step S11: Weigh two groups of 0.10g sodium pyroantimonate samples A respectively, and record them as A-1 and A-2 respectively; Step S12: Place each group of sodium pyroantimonate samples (A-1 and A-2) into a 100 mL steel volumetric flask; Next, add 3 mL to 5 mL of deionized water to wet the sodium pyroantimonate samples (A-1 and A-2). Step S211: Add 5 mL of nitric acid (analytical grade) to a steel volumetric flask. Step S212: Add 0.5g of tartaric acid (analytical grade) to a steel volumetric flask. Step S22: Preheat the steel volumetric flask to a temperature of 180℃-230℃ for 10 minutes. Step S31: Heat 2.5 mL of hydrochloric acid (analytical grade) in a steel volumetric flask. Step S32: Reheat the steel volumetric flask at a temperature of 180℃-230℃ until the sodium pyroantimonate samples (A-1 and A-2) are completely digested; Next, cool the steel volumetric flask to room temperature; Step S41: Make up the volume of the completely digested sodium pyroantimonate samples (A-1 and A-2). Specifically, use deionized water to bring the solution in the steel volumetric flask to the mark to obtain the test solution; Step S51: Determine the content of harmful elements in the test solution. Specific operating steps include: (1) Take another 100mL steel volumetric flask, add equal amounts of nitric acid, tartaric acid, and hydrochloric acid to the steel volumetric flask, and dilute with deionized water to obtain a blank solution; (2) According to GSB 04-1714-2004 (containing 1000 μg / mL arsenic, medium is 1.0 mol / L nitric acid), standard working solutions of 0 μg / mL, 0.1 μg / mL, 0.3 μg / mL, 0.5 μg / mL, 1.0 μg / mL, 3.0 μg / mL, 5.0 μg / mL, and 10.0 μg / mL were prepared by stepwise dilution. If the arsenic content in the test solution exceeds the concentration range of the standard working solution, the test solution can be diluted, and the dilution factor is recorded as f; (3) The arsenic concentration in the standard working solution was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The ICP conditions included: vertical mode, using a 189.042 nm signal as the quantitative signal, and plotting an arsenic standard curve using concentration-signal intensity. (4) The concentrations of arsenic in each test solution and blank solution were determined using an inductively coupled plasma atomic emission spectrometer (ICP-AES). The concentrations of arsenic in the test solutions and blank solutions were determined using a standard curve and denoted as c. [As] c 空白[As] ; (5) Calculate the As content in the sodium pyroantimonate sample according to the following formula. : , Where m is the weighing weight of the sodium pyroantimonate sample in g; V is the final volume in mL; and f is the dilution factor of the test solution.

[0036] Table 1. Arsenic (As) content in sodium pyroantimonate sample A As shown in Table 1, the relative deviation of arsenic content in sodium pyroantimonate samples obtained by the method of the present invention is less than 2%, indicating that the present invention can accurately measure the content of harmful elements in sodium pyroantimonate samples, and the results have high accuracy and reliability. Example 2 Step S11: Weigh two groups of 0.10g sodium pyroantimonate samples B respectively, and record them as B-1 and B-2 respectively; Step S12: Place each group of sodium pyroantimonate samples (B-1 and B-2) into a 100 mL steel volumetric flask; Next, add 3 mL to 5 mL of deionized water to wet the sodium pyroantimonate samples (B-1 and B-2). Step S211: Add 5 mL of nitric acid (analytical grade) to a steel volumetric flask. Step S212: Add 0.1g of tartaric acid (analytical grade) to a steel volumetric flask. Step S22: Preheat the steel volumetric flask to a temperature of 180℃-230℃ for 10 minutes. Step S31: Heat 2.5 mL of hydrochloric acid (analytical grade) in a steel volumetric flask. Step S32: Reheat the steel volumetric flask at a temperature of 180℃-230℃ until the sodium pyroantimonate samples (B-1 and B-2) are completely digested; Next, cool the steel volumetric flask to room temperature; Step S41: Make up the volume of the completely digested sodium pyroantimonate samples (B-1 and B-2). Specifically, use deionized water to bring the solution in the steel volumetric flask to the mark to obtain the test solution; Step S51: Determine the content of harmful elements in the test solution. Specific operating steps include: (1) Take another 100mL steel volumetric flask, add equal amounts of nitric acid, tartaric acid, and hydrochloric acid to the steel volumetric flask, and dilute with deionized water to obtain a blank solution; (2) According to GSB 04-1714-2004 (containing 1000 μg / mL arsenic, medium is 1.0 mol / L nitric acid), standard working solutions of 0 μg / mL, 0.1 μg / mL, 0.3 μg / mL, 0.5 μg / mL, 1.0 μg / mL, 3.0 μg / mL, 5.0 μg / mL, and 10.0 μg / mL were prepared by stepwise dilution. If the arsenic content in the test solution exceeds the concentration range of the standard working solution, the test solution can be diluted, and the dilution factor is recorded as f; (3) The arsenic concentration in the standard working solution was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The ICP conditions included: vertical mode, using a 189.042 nm signal as the quantitative signal, and plotting an arsenic standard curve using concentration-signal intensity. (4) The concentrations of arsenic in each test solution and blank solution were determined using an inductively coupled plasma atomic emission spectrometer (ICP-AES). The concentrations of arsenic in the test solutions and blank solutions were determined using a standard curve and denoted as c. [As] c 空白[As] ; (5) Calculate the As content in the sodium pyroantimonate sample according to the following formula. : , Where m is the weighing weight of the sodium pyroantimonate sample in g; V is the final volume in mL; and f is the dilution factor of the test solution.

[0038] Table 2. Arsenic content in sodium pyroantimonate sample B Example 3 Step S11: Weigh 0.10 g of sodium pyroantimonate sample C, wherein sample C and sample B are derived from the same parent sample. Step S12: Place sodium pyroantimonate sample C into a 100 mL steel volumetric flask; Next, add 3-5 mL of deionized water to wet sodium pyroantimonate sample C; Step S21: Add 5 mL of nitric acid (analytical grade) to a steel volumetric flask. Step S22: Preheat the steel volumetric flask to a temperature of 180℃-230℃ for 10 minutes. Step S31: Heat 2.5 mL of hydrochloric acid (analytical grade) in a steel volumetric flask. Step S32: Reheat the steel volumetric flask at a temperature of 180℃-230℃ until the sodium pyroantimonate sample C is completely digested. Next, cool the steel volumetric flask to room temperature; Step S41: Make up the volume of the completely digested sodium pyroantimonate sample C. Specifically, use deionized water to make up the volume of the solution in the steel volumetric flask to the mark to obtain the test solution; Step S51: Determine the content of harmful elements in the test solution. Specific operating steps include: (1) Take another 100mL steel volumetric flask, add equal amounts of nitric acid and hydrochloric acid to the steel volumetric flask and dilute with deionized water to obtain a blank solution; (2) According to GSB 04-1714-2004 (containing 100 μg / mL of aluminum, arsenic, boron, barium, beryllium, bismuth, cadmium, cobalt, chromium, copper, iron, gallium, lithium, magnesium, manganese, nickel, lead, antimony, tin, strontium, titanium, thallium, vanadium, and zinc, in a medium of 2.5 mol / L nitric acid and trace amounts of hydrochloric acid), standard working solutions of 0 μg / mL, 0.1 μg / mL, 0.3 μg / mL, 0.5 μg / mL, 1.0 μg / mL, 3.0 μg / mL, 5.0 μg / mL, and 10.0 μg / mL were prepared by stepwise dilution. If the arsenic content in the test solution exceeds the concentration range of the standard working solution, the test solution can be diluted, and the dilution factor is recorded as f. (3) The arsenic concentration in the standard working solution was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). ICP conditions: vertical mode, and an arsenic standard curve was plotted using concentration-signal intensity. (4) Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to measure the concentrations of harmful elements in each test solution and blank solution. The concentrations in the test solutions and blank solutions were determined using a standard curve and denoted as c. [元素] c 空白[元素] ; (5) Calculate the content of harmful elements in the sodium pyroantimonate sample according to the following formula. : , Where m is the weighing weight of the sodium pyroantimonate sample in g; V is the final volume in mL; and f is the dilution factor of the test solution.

[0040] Table 3. Content of harmful elements in sodium pyroantimonate sample C

[0041] As shown in Tables 2 and 3, the arsenic content obtained in Specific Example 2 was approximately 0.0824%, while the arsenic content obtained in Specific Example 3 was 0.0822%. The results are close, indicating that the addition of tartaric acid to the digestion container has little impact on the final determination results. It should be noted that the applicant found that the test solution without tartaric acid may precipitate after prolonged standing at room temperature (e.g., after 24 hours), requiring prompt measurement; however, the test solution with tartaric acid showed no precipitate after standing at room temperature for 24 hours, indicating that tartaric acid provides the test solution with a longer stability.

[0042] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for determining the content of harmful elements in a sodium pyroantimonate sample, characterized in that, The determination method includes: weighing a first predetermined mass of the sodium pyroantimonate sample and placing it in a digestion container; adding a first predetermined volume of oxidizing acid to the digestion container and preheating the digestion container; adding a second predetermined volume of hydrochloric acid to the digestion container and reheating the digestion container to completely digest the sodium pyroantimonate sample; adjusting the volume of the completely digested sodium pyroantimonate sample to obtain a test solution; and determining the content of harmful elements in the test solution.

2. The method for determining the content of harmful elements in sodium pyroantimonate samples according to claim 1, characterized in that, While adding a first predetermined volume of oxidizing acid into the digestion container, a second predetermined mass of tartaric acid is added into the digestion container.

3. The method for determining the content of harmful elements in sodium pyroantimonate samples according to claim 2, characterized in that, The ratio between the first predetermined mass and the second predetermined mass ranges from 0.1 to 5.

4. The method for determining the content of harmful elements in sodium pyroantimonate samples according to any one of claims 1-3, characterized in that, The oxidizing acid includes nitric acid or perchloric acid.

5. The method for determining the content of harmful elements in sodium pyroantimonate samples according to any one of claims 1-3, characterized in that, The ratio between the first predetermined volume and the second predetermined volume ranges from 0.1 to 5.

6. The method for determining the content of harmful elements in sodium pyroantimonate samples according to any one of claims 1-3, characterized in that, The harmful elements include one or more of arsenic, lead, cadmium, chromium, nickel, and bismuth.

7. The method for determining the content of harmful elements in sodium pyroantimonate samples according to any one of claims 1-3, characterized in that, The digestion container is a conical flask or a steel volumetric flask.

8. The method for determining the content of harmful elements in sodium pyroantimonate samples according to any one of claims 1-3, characterized in that, The temperature ranges for the preheating and reheating are 150℃-230℃, respectively.

9. The method for determining the content of harmful elements in sodium pyroantimonate samples according to claim 8, characterized in that, The preheating time is 2 min to 12 min.

10. The method for determining the content of harmful elements in sodium pyroantimonate samples according to any one of claims 1-3, characterized in that, The content of harmful elements in the test solution is determined using an inductively coupled plasma atomic emission spectrometer, an atomic absorption spectrophotometer, or an atomic fluorescence spectrophotometer.

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