A method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry

Abstract

This invention discloses a method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry, characterized by the following steps: (1) placing high-purity metallic vanadium powder on a high-purity indium block, applying pressure and tapping repeatedly to form a sheet-like sample to be tested; (2) fixing the sample obtained in step (1) with a sample clamp and placing it in the sample chamber of the glow discharge mass spectrometer. The sample is evacuated by the ion source and pushed into the discharge chamber. The discharge current is set to 0.9–1.5 mA, the discharge gas flow rate to 200–260 mL / min, and the discharge voltage to 1–1.5 kV. Based on the semi-quantitative analysis principle of glow discharge mass spectrometry, the mass fraction of each element to be tested in the high-purity metallic vanadium powder is calculated using the relative sensitivity factor. Compared with the prior art, the method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry of this invention is simple to operate.

Description

Technical Field

[0001] This invention relates to the field of sample analysis and detection technology, specifically to a method for testing high-purity metallic vanadium powder using glow discharge mass spectrometry. Background Technology

[0002] Vanadium is a silvery-white rare metal with excellent properties such as high melting point, low activation, high hardness, corrosion resistance, and small fast neutron absorption cross section. It ranks 21st in abundance in the Earth's crust, higher than commonly used metals silver and copper; it is the second most abundant transition metal element in seawater. Global vanadium resources are mainly concentrated in a few countries and regions. However, my country is the world's largest producer, supplier, and consumer of vanadium, accounting for more than 60% of global production. Maintaining its leading position in the vanadium industry is a major national strategic need.

[0003] Vanadium, a strategically critical metal, is often referred to as a "metallic vitamin" due to its wide range of applications, currently encompassing metallurgy, chemical engineering, energy, aerospace, nuclear energy, and pharmaceuticals. Vanadium products are classified into three grades: primary vanadium products such as vanadium slag; secondary vanadium products such as vanadium oxide (vanadium pentoxide); and tertiary vanadium products such as vanadium alloys and pure metallic vanadium. Pure metallic vanadium generally refers to vanadium with a purity between 99% and 99.9%, while vanadium with a purity exceeding 99.9% is considered high-purity metallic vanadium.

[0004] In recent years, vanadium has gradually become an indispensable metallic resource in many fields such as nuclear power, superconducting materials, aerospace, and clean energy. Research on high-purity vanadium in hydrogen storage alloys and hydrogen separation membranes, high-temperature superconducting materials, and coating materials and heat-releasing elements for fuel rods in high-speed breeder reactors is also increasing. Most recently, in April 2022, an Australian vanadium company successfully developed a vanadium redox flow battery and simultaneously built a vanadium electrolyte production plant with an annual capacity of 33 MWh, further paving the way for the future establishment of independent electric vehicle charging stations.

[0005] Therefore, the research and optimization of high-purity vanadium metal preparation technology and the improvement of high-purity vanadium metal purity detection technology are of great significance to promoting the development of my country's rare metal materials field. High-purity vanadium metal powder is an important raw material for vanadium products, so it is necessary to test the high-purity vanadium powder when preparing products by powder metallurgy. Currently, glow discharge mass spectrometry (GD-MS) has the advantages of being pollution-free, fast detection speed, low resolution, and full element detection, and is the most widely used ultra-high purity metal detection technology.

[0006] There are few reports on methods for determining trace elements in high-purity metallic vanadium. Patent application CN202210072450.6 (publication CN114438472A), entitled "Large-size Ultra-high-purity vanadium sputtering target for integrated circuit chips and its preparation process," discloses a process for preparing large-size ultra-high-purity vanadium sputtering targets for integrated circuit chips using high-purity vanadium powder, aiming to obtain vanadium targets with a purity of 99.9999% to meet the needs of the integrated circuit chip and other electronic industries. Patent application CN201210572028.3 (publication CN103048309A), entitled "Method for determining vanadium content," discloses a method for determining vanadium content. However, in the above methods, vanadium-containing samples are digested with hydrochloric acid and measured using inductively coupled plasma atomic emission spectrometry (ICP-AES), which can only detect 1% vanadium content. The vanadium content of 0wt%-45wt% is not suitable for high-purity vanadium and cannot meet the analytical requirements. The invention patent "A sample preparation method and test method of ammonium paratungstate powder for glow discharge mass spectrometry" with patent application number CN202110757173.8 (publication number CN113358442A) discloses a sample preparation method and test method of ammonium paratungstate powder for glow discharge mass spectrometry. The above method places the sample in a groove opened on the surface of a high-purity indium sheet. Wang Yanhui et al. (Wang Yanhui, Liu Qi, Bo Xinwei. Study on sintering performance of high-purity metallic vanadium powder [J]. Metallurgical Technology. 2019, 37(5):339-343) have found that high-purity metallic vanadium has a low relative density below 40MP and cannot be formed. It cannot be fixed in the groove, and excessive pressure will cause the indium sheet to be overstretched and the groove to disappear.

[0007] In summary, there is an urgent need to develop a simple and easy-to-operate sample preparation and testing method that is applicable to glow discharge mass spectrometry. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a simple method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry, in light of the current state of the technology.

[0009] The technical solution adopted by this invention to solve the above-mentioned technical problems is as follows: a method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry, characterized by comprising the following steps:

[0010] (1) Place high-purity vanadium powder on a high-purity indium block, apply pressure and tap lightly, repeating this process multiple times to prepare a sheet-like sample to be tested.

[0011] (2) Fix the sample to be tested obtained in step (1) with a sample clamp and place it in the sample chamber of the glow discharge mass spectrometer. The sample to be tested is evacuated by the ion source and pushed into the discharge chamber. Set the discharge current to 0.9-1.5mA, the discharge gas flow rate to 200-260mL / min, and the discharge voltage to 1-1.5kV. According to the semi-quantitative analysis principle of glow discharge mass spectrometer, the mass fraction of each element to be tested in high-purity metallic vanadium powder is calculated by applying the relative sensitivity factor.

[0012] Preferably, the purity of the high-purity indium block in step (1) is ≥6N.

[0013] Preferably, the specific preparation method of the high-purity indium block in step (1) is as follows: cut the high-purity indium into blocks with a polytetrafluoroethylene knife to obtain the required high-purity indium block, wash it continuously with concentrated nitric acid, ultrapure water and anhydrous ethanol in a volume ratio of 1:1, and put it in anhydrous ethanol for later use.

[0014] Further, the specific preparation method of the sheet-like test sample in step (1) is as follows: Take out the high-purity indium block, blow it dry, place the high-purity metallic vanadium powder on the plane of the high-purity indium block, press it into a tablet using a manual tablet press, take it out, tap the back with a polytetrafluoroethylene rod to remove floating powder, repeat the operation to make the prepared sample compact and without powder falling off, and obtain the required sheet-like test sample.

[0015] Furthermore, the compression time for each tableting session is ≤1 min.

[0016] Furthermore, the number of repetitions is 3 to 4.

[0017] Preferably, the diameter of the sheet-like sample to be tested in step (1) is 25-30 mm and the thickness is 2-4 mm, and the diameter of the area where the high-purity vanadium metal powder is spread on the sheet-like sample to be tested is 15-20 mm.

[0018] Preferably, the resolution of the element to be measured in step (2) is >4000.

[0019] Preferably, the signal strength of the element to be measured in step (2) is ≥1.5×10⁻⁶. 8 .

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] (1) By placing high-purity vanadium metal powder on a high-purity indium block and pressing it to form a sheet-like sample to be tested, the physical properties of indium are utilized to prepare a high-purity vanadium metal powder sample with a compact structure suitable for detection by glow discharge mass spectrometry under low pressure. The sample preparation operation is simple and highly repeatable, which can effectively solve the problem that high-purity vanadium metal powder cannot be directly injected.

[0022] (2) For high-purity metallic vanadium powder, by setting appropriate test parameters, a resolution >4000 and a resolution ≥1.5×10⁻⁶ can be obtained. 8 The test signal has high sensitivity and high accuracy, which can well meet the requirements of the method for simultaneous detection of multiple trace impurities in high-purity metallic vanadium powder, and meet the needs of scientific research and production testing. Attached Figure Description

[0023] Figure 1 This is a photograph of the sheet-like sample to be tested prepared in Example 1 of the present invention. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] Example 1:

[0026] (1) Select high-purity indium with a purity of 6N, cut it into blocks weighing 2.15g with a polytetrafluoroethylene knife, soak it in a nitric acid solution with a volume ratio of 1:1 for 40s, rinse it three times with ultrapure water, and put it in anhydrous ethanol for later use.

[0027] Immerse the polytetrafluoroethylene spoon, polytetrafluoroethylene rod, and polytetrafluoroethylene tweezers in a nitric acid solution with a volume ratio of 1:1 for 1 minute, rinse three times with ultrapure water, and place them in anhydrous ethanol for later use.

[0028] The indium block was removed and dried using PTFE tweezers. A small amount of high-purity vanadium powder was taken using a PTFE spoon and placed in the center of the high-purity indium block. The block was then placed on a manual tablet press and pressurized for 30 seconds. The indium block was then removed and the back was gently tapped with a PTFE rod to remove any loose powder. This process was repeated three times to ensure that the sample was compact and would not fall off when the sample was tapped lightly on its side. The diameter of the sample to be tested was 27 mm and the thickness was 3 mm. The diameter of the area where the high-purity vanadium powder was spread on the sheet-like sample was 17 mm.

[0029] (2) The sample to be tested obtained in step (1) was fixed with a sample clamp and placed in the sample chamber of the Nu Astrum glow discharge mass spectrometer. The sample to be tested was evacuated by the ion source and pushed into the discharge chamber, cooled to -180℃, and the discharge current was set to 1.01mA, the discharge gas flow rate to 250mL / min, the discharge voltage to 1.5kV, the resolution of the sample to be tested to be 4123, and the signal intensity of the sample to be tested to be 1.6×10⁻⁶. 8 Test data can be obtained after 30 minutes of testing.

[0030] Example 2:

[0031] (1) Select high-purity indium with a purity of 6N, cut it into blocks weighing 1.90g with a polytetrafluoroethylene knife, soak it in a nitric acid solution with a volume ratio of 1:1 for 40s, rinse it three times with ultrapure water, and put it in anhydrous ethanol for later use.

[0032] Immerse the polytetrafluoroethylene spoon, polytetrafluoroethylene rod, and polytetrafluoroethylene tweezers in a nitric acid solution with a volume ratio of 1:1 for 1 minute, rinse three times with ultrapure water, and place them in anhydrous ethanol for later use.

[0033] The indium block was removed and dried using PTFE tweezers. A small amount of high-purity vanadium powder was taken using a PTFE spoon and placed in the center of the high-purity indium block. The block was then placed on a manual tablet press and pressurized for 30 seconds. The indium block was then removed and the back was gently tapped with a PTFE rod to remove any loose powder. This process was repeated three times to ensure that the sample was compact and would not fall off when the sample was tapped lightly on its side. The diameter of the sample to be tested was 25 mm, the thickness was 2 mm, and the diameter of the area where the high-purity vanadium powder was spread on the sheet-like sample was 15 mm.

[0034] (2) The sample to be tested obtained in step (1) was fixed with a sample clamp and placed in the sample chamber of the Nu Astrum glow discharge mass spectrometer. The sample to be tested was evacuated by the ion source and pushed into the discharge chamber, cooled to -180℃, and the discharge current was set to 0.9mA, the discharge gas flow rate to 200mL / min, the discharge voltage to 1.0kV, the resolution of the sample to be tested to be 4019, and the signal intensity of the sample to be tested to be 1.53×10⁻⁶. 8 Test data can be obtained after 30 minutes of testing.

[0035] Example 3:

[0036] (1) Select high-purity indium with a purity of 6N, cut it into blocks weighing 2.03g with a polytetrafluoroethylene knife, soak it in a nitric acid solution with a volume ratio of 1:1 for 40s, rinse it three times with ultrapure water, and put it in anhydrous ethanol for later use.

[0037] Immerse the polytetrafluoroethylene spoon, polytetrafluoroethylene rod, and polytetrafluoroethylene tweezers in a nitric acid solution with a volume ratio of 1:1 for 1 minute, rinse three times with ultrapure water, and place them in anhydrous ethanol for later use.

[0038] The indium block was removed and dried using PTFE tweezers. A small amount of high-purity vanadium powder was taken using a PTFE spoon and placed in the center of the high-purity indium block. The block was then placed on a manual tablet press and pressurized for 30 seconds. The indium block was then removed and the back was gently tapped with a PTFE rod to remove any loose powder. This process was repeated three times to ensure that the sample was compact and would not fall off when the sample was tapped lightly on its side. The diameter of the sample to be tested was 30 mm and the thickness was 4 mm. The diameter of the area where the high-purity vanadium powder was spread on the sheet-like sample was 20 mm.

[0039] (2) The sample to be tested obtained in step (1) was fixed with a sample clamp and placed in the sample chamber of the Nu Astrum glow discharge mass spectrometer. The sample to be tested was evacuated by the ion source and pushed into the discharge chamber, cooled to -180℃, and the discharge current was set to 1.5mA, the discharge gas flow rate to 260mL / min, the discharge voltage to 1.3kV, the resolution of the sample to be tested to be 4714, and the signal intensity of the sample to be tested to be 2.6×10⁻⁶. 8 Test data can be obtained after 30 minutes of testing.

[0040] The photograph of the sheet-like sample to be tested prepared in Example 1 above is shown below. Figure 1 As shown.

[0041] Based on the semi-quantitative analysis principle of glow discharge mass spectrometry, the mass fraction of each analyte in high-purity metallic vanadium powder is calculated using the relative sensitivity factor. The mass fraction of each analyte in the high-purity metallic vanadium powder in Example 1 above is shown in Table 1.

[0042] Table 1: Mass fraction of each element to be tested in high-purity vanadium powder in Example 1

[0043]

[0044]

[0045] Depend on Figure 1 As can be seen from Table 1:

[0046] (1) By placing high-purity vanadium metal powder on a high-purity indium block and pressing it to form a sheet-like sample to be tested, the physical properties of indium are utilized to prepare a high-purity vanadium metal powder sample with a compact structure suitable for detection by glow discharge mass spectrometry under low pressure. The sample preparation operation is simple and highly repeatable, which can effectively solve the problem that high-purity vanadium metal powder cannot be directly injected.

[0047] (2) For high-purity metallic vanadium powder, by setting appropriate test parameters, a resolution >4000 and a resolution ≥1.5×10⁻⁶ can be obtained. 8 The test signal has high sensitivity and high accuracy, which can well meet the requirements of the method for simultaneous detection of multiple trace impurities in high-purity metallic vanadium powder, and meet the needs of scientific research and production testing.

Claims

1. A method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry, characterized in that... It includes the following steps: (1) Place high-purity vanadium powder on a high-purity indium block, apply pressure and tap lightly, repeating this process multiple times to prepare a sheet-like sample to be tested. (2) Fix the sample to be tested obtained in step (1) with a sample clamp and place it in the sample chamber of the glow discharge mass spectrometer. The sample to be tested is evacuated by the ion source and pushed into the discharge chamber. Set the discharge current to 0.9-1.5mA, the discharge gas flow rate to 200-260mL / min, and the discharge voltage to 1-1.5kV. According to the semi-quantitative analysis principle of glow discharge mass spectrometer, the mass fraction of each element to be tested in high-purity metallic vanadium powder is calculated by applying the relative sensitivity factor. The specific preparation method of the sheet-like test sample in step (1) is as follows: Take out the high-purity indium block, blow it dry, place the high-purity vanadium metal powder on the plane of the high-purity indium block, press it into a tablet using a manual tablet press, take it out, tap the back with a polytetrafluoroethylene rod to remove the floating powder, repeat the operation to make the prepared sample compact and without powder falling off, and obtain the required sheet-like test sample. The pressing time for each tablet is ≤1min, and the number of repeated operations is 3 to 4 times. The diameter of the sheet-like sample to be tested in step (1) is 25-30 mm and the thickness is 2-4 mm. The diameter of the area where the high-purity vanadium metal powder is spread on the sheet-like sample to be tested is 15-20 mm. In step (2), the resolution of the element to be measured is >4000; In step (2), the signal strength of the element to be measured should be ≥1.5×10⁻⁶. 8 .

2. The method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry according to claim 1, characterized in that: The purity of the high-purity indium block mentioned in step (1) is ≥6N.

3. The method for testing high-purity metallic vanadium powder by glow discharge mass spectrometry according to claim 1, characterized in that: The specific preparation method of the high-purity indium block in step (1) is as follows: cut the high-purity indium into blocks with a polytetrafluoroethylene knife to obtain the required high-purity indium block, wash it continuously with concentrated nitric acid, ultrapure water and anhydrous ethanol in a volume ratio of 1:1, and put it in anhydrous ethanol for later use.

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