Method for detecting fluorine element in nickel-cobalt-manganese hydroxide
By using a composite sealed digestion system and complexation reaction to form a stable AlF63- compound, combined with ICP-MS detection, the problems of high volatilization rate and spectral interference in the detection of fluorine in nickel-cobalt-manganese ternary precursors were solved, achieving efficient and accurate fluorine detection and meeting the process control requirements with low detection limits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-03-27
AI Technical Summary
Existing technologies for detecting fluorine impurities in nickel-cobalt-manganese ternary precursors suffer from problems such as high HF volatilization rate, spectral interference caused by Ni, Co, and Mn elements, and insufficient detection limits, resulting in low detection results and cumbersome procedures.
A composite sealed digestion system was used to mix with flux for preliminary microwave digestion and complexation reaction. Combined with ICP-MS detection, the complexation reaction was used to form a stable AlF63- compound, reducing the volatilization of fluorine. The volatilized HF was collected by an integrated multi-stage condenser reflux device and quantitatively analyzed by high-resolution inductively coupled plasma mass spectrometry.
This method enables efficient and accurate detection of fluorine in nickel-cobalt-manganese hydroxides, reduces volatilization loss, improves the repeatability and accuracy of detection results, and meets the process control requirements with low detection limits.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of elemental detection technology, and more specifically, to a method for detecting fluorine in nickel-cobalt-manganese hydroxide. Background Technology
[0002] The presence of fluorine impurities in nickel-cobalt-manganese ternary precursors can have several negative effects, such as disrupting the crystal structure, reducing electrochemical performance, and affecting production stability. Therefore, the content of fluorine impurities is typically tested during quality control of nickel-cobalt-manganese ternary precursors.
[0003] Currently, the detection of fluorine impurities in nickel-cobalt-manganese ternary precursors mainly faces the following problems: (1) The volatilization rate of HF under high temperature conditions is as high as 40%~60%, which leads to a systematic underestimation of the detection results; (2) High concentrations of Ni, Co, and Mn elements in ternary precursors can cause significant spectral interference; (3) Conventional X-ray fluorescence method has insufficient detection limit for light element F (>200ppm), while ion chromatography has higher sensitivity, but requires a complicated distillation separation pretreatment process (average time of about 3h per sample).
[0004] In view of this, the present invention is proposed. Summary of the Invention
[0005] The purpose of this invention is to provide a method for detecting fluorine in nickel cobalt manganese hydroxide, so as to solve or improve at least one of the above-mentioned technical problems.
[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a method for detecting fluorine in nickel cobalt manganese hydroxide, comprising the following steps: mixing nickel cobalt manganese hydroxide with a flux and then subjecting it to preliminary microwave digestion with concentrated nitric acid and hydrofluoric acid in a composite sealed digestion system, followed by complexation reaction with aluminum nitrate solution; after the complexation reaction is completed, the resulting reaction solution is detected by ICP-MS.
[0007] In an optional embodiment, the mass ratio of nickel cobalt manganese hydroxide to flux is 0.1:1 to 0.5:1.
[0008] In an optional implementation, the flux includes boric acid.
[0009] In an optional embodiment, the ratio of nickel cobalt manganese hydroxide to concentrated nitric acid is (0.1g~0.5g):(3mL~7mL); And / or, the ratio of nickel cobalt manganese hydroxide to hydrofluoric acid is (0.1g~0.5g):(0.5mL~2mL).
[0010] In an optional embodiment, the concentration of concentrated nitric acid is 62% to 68%; And / or, the concentration of hydrofluoric acid is 38%~42%.
[0011] In an optional implementation, preliminary microwave digestion is performed at 60°C to 100°C for 15 to 20 minutes.
[0012] In an optional embodiment, the ratio of nickel cobalt manganese hydroxide to aluminum nitrate solution is (0.1g~0.5g):(1mL~3mL).
[0013] In an optional embodiment, the concentration of the aluminum nitrate solution is 5% to 15%.
[0014] In an optional embodiment, the complexation reaction is carried out by heating to 120°C to 180°C at a rate of 3°C / min to 8°C / min, followed by holding at that temperature for 10 min to 30 min.
[0015] In an optional embodiment, the composite sealed digestion system is a digestion vessel made of PTFE and carbon fiber laminate.
[0016] In an optional implementation, reflux is performed simultaneously with the initial microwave digestion and complexation reaction using an integrated multi-stage condensation reflux device.
[0017] In an optional implementation, a high-resolution inductively coupled plasma mass spectrometer equipped with a collision reaction cell is used for detection.
[0018] In optional implementations, a standard mode or a kinetic discrimination mode is used, and the built-in interference correction equation of the instrument software is used to eliminate interference to F; then, the external standard method or the standard addition method is used for quantitative analysis.
[0019] The beneficial effects of this invention include: The method for detecting fluorine in nickel-cobalt-manganese hydroxide provided by this invention is simple to operate, time-saving, and efficient. It can reduce the volatilization loss of fluorine during the measurement process, and the measured results are highly accurate and repeatable. It can effectively meet the process control requirements for fluorine content <10ppm or even lower. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0021] The method for detecting fluorine in nickel-cobalt-manganese hydroxide provided by this invention will be described in detail below.
[0022] This invention provides a method for detecting fluorine in nickel cobalt manganese hydroxide, comprising the following steps: mixing nickel cobalt manganese hydroxide with a flux and then subjecting it to preliminary microwave digestion with concentrated nitric acid and hydrofluoric acid in a composite sealed digestion system, followed by complexation reaction with aluminum nitrate solution; after the complexation reaction is completed, the resulting reaction solution is detected by ICP-MS.
[0023] In some alternative embodiments, the mass ratio of nickel cobalt manganese hydroxide to flux can be from 0.1:1 to 0.5:1, such as 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or 0.5:1, or other values within the range of 0.1:1 to 0.5:1.
[0024] The fluxing agent described above may, by way of example, include boric acid.
[0025] The aforementioned flux can lower the melting temperature, reduce the damage of high temperatures to the sample, and stabilize fluorine (F). Without flux, during high-temperature atomization or excitation, fluorine will be encapsulated by solid particles of oxides or complex salts, making it difficult for F to completely convert to a detectable form, affecting the accuracy and precision of the detection results. However, if too much flux is used, excess boric acid will almost entirely complex the fluoride ions released in the solution into BF4. - This causes the concentration of free fluoride ions to approach the detection limit, or even become undetectable, and long-term use will shorten the lifespan of the detector.
[0026] In some alternative embodiments, the ratio of nickel cobalt manganese hydroxide to concentrated nitric acid can be (0.1g~0.5g):(3mL~7mL), such as 0.1g:3mL, 0.2g:3mL, 0.3g:3mL, 0.4g:3mL, 0.5g:3mL, 0.1g:5mL, 0.2g:5mL, 0.3g:5mL, 0.4g:5mL, 0.1g:7mL, 0.2g:7mL, 0.3g:7mL, 0.4g:7mL, or 0.5g:7mL, etc., or other values within the range of (0.1g~0.5g):(3mL~7mL).
[0027] The concentration of concentrated nitric acid can be 62% to 68%, such as 62%, 63%, 64%, 65%, 66%, 67% or 68%, or other values within the range of 62% to 68%.
[0028] The ratio of nickel cobalt manganese hydroxide to hydrofluoric acid can be (0.1g~0.5g):(0.5mL~2mL), such as 0.1g:0.5mL, 0.2g:0.5mL, 0.3g:0.5mL, 0.4g:0.5mL, 0.5g:0.5mL, 0.1g:1mL, 0.2g:1mL, 0.3g:1mL, 0.4g:1mL, 0.5g:1mL, 0.1g:1.5mL, 0.2g:1.5mL, 0.3g:1.5mL, 0.4g:1.5mL, 0.5g:1.5mL, 0.1g:2mL, 0.2g:2mL, 0.3g:2mL, 0.4g:2mL, or 0.5g:2mL, etc., or other values within the range of (0.1g~0.5g):(0.5mL~2mL).
[0029] The concentration of hydrofluoric acid can be 38% to 42%, such as 38%, 39%, 40%, 41% or 42%, or other values within the range of 38% to 42%.
[0030] In some alternative implementations, preliminary microwave digestion is carried out at 60°C to 100°C for 15 to 20 minutes.
[0031] The initial microwave digestion temperature can be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃, or other values within the range of 60℃ to 100℃.
[0032] If the initial microwave digestion temperature is below 60℃, it is not conducive to the reaction and may result in incomplete digestion, affecting the accuracy of the data; if the initial microwave digestion temperature is above 100℃, the reaction is too violent, causing sample loss.
[0033] The initial microwave digestion time can be 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, or other values within the range of 15 min to 20 min.
[0034] In some of the listed embodiments, the above-mentioned preliminary microwave digestion process can be carried out as follows: concentrated nitric acid and hydrofluoric acid are first added to the digestion vessel containing nickel cobalt manganese hydroxide, the digestion vessel is sealed, and then the temperature is raised and maintained at this temperature for 15 min to 20 min.
[0035] As mentioned above, the initial microwave digestion is an acidic decomposition phase, primarily aimed at dissolving nickel-cobalt-manganese hydroxide and releasing F. - During this stage, HF is responsible for disrupting the precursor oxide lattice, releasing F. -However, a large amount of unreacted free HF is also present, posing a very high risk of volatilization. Based on this, the present invention further carries out a complexation reaction.
[0036] In some alternative embodiments, the ratio of nickel cobalt manganese hydroxide to aluminum nitrate solution can be (0.1g~0.5g):(1mL~3mL), such as 0.1g:1mL, 0.2g:1mL, 0.3g:1mL, 0.4g:1mL, 0.5g:1mL, 0.1g:2mL, 0.2g:2mL, 0.3g:2mL, 0.4g:2mL, 0.5g:2mL, 0.1g:3mL, 0.2g:3mL, 0.3g:3mL, 0.4g:3mL, or 0.5g:3mL, etc., or other values within the range of (0.1g~0.5g):(1mL~3mL).
[0037] The concentration of the aluminum nitrate solution can be 5% to 15%, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%, or other values within the range of 5% to 15%. That is, 100 mL of aluminum nitrate solution contains 5 g to 15 g of aluminum nitrate.
[0038] In some alternative embodiments, the complexation reaction is carried out by heating to 120°C to 180°C at a rate of 3°C / min to 8°C / min, followed by holding at that temperature for 10 min to 30 min.
[0039] The heating rate of the complexation reaction can be 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min or 8℃ / min, or other values within the range of 3℃ / min to 8℃ / min.
[0040] The temperature for the complexation reaction can be 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃ or 180℃, or other values within the range of 120℃ to 180℃.
[0041] If the temperature of the complexation reaction is below 120℃, it is not conducive to the efficient formation of coordination bonds and the completeness of the reaction; if the temperature of the complexation reaction is above 180℃, it is not conducive to the existence of stable complexes and the purity of the target product.
[0042] The complexation reaction time can be 10 min, 15 min, 20 min, 25 min or 30 min, or other values within the range of 10 min to 30 min.
[0043] In some of the listed embodiments, the complexation reaction process can be carried out as follows: Aluminum nitrate solution is slowly injected through a dedicated reagent injection port on the digestion vessel while maintaining system pressure and temperature; after injection, the complexation reaction continues during heating and temperature maintenance. The reaction equations involved in the complexation reaction include: Al 3+ +6F - AlF6 3- .
[0044] It should be noted that in this invention, the complexing agent (aluminum nitrate solution) is not added all at once before digestion, but rather during the process. - Adding it at a critical moment when a large amount has already been released and volatilization is about to occur avoids Al 3+ Premature precipitation with HF or side reactions with other acid radicals are avoided, thus achieving precise and efficient complexation. The AlF6 complex formed... 3- The complex exhibits extremely high thermodynamic stability at the digestion temperature (ΔG is approximately 298.4 kJ / mol) and is almost non-volatile, thus effectively "locking" fluorine in the solution. In other words, this method eliminates the driving force for HF volatilization at its chemical source, converting fluorine into a stable form.
[0045] In some alternative embodiments, the composite sealed digestion system is a digestion vessel made of PTFE and carbon fiber laminate. By employing the above-mentioned composite sealed digestion system, the pressure resistance can be increased by 300% compared to conventional vessels (made of PTFE), for example, to 1.2 MPa.
[0046] In some alternative implementations, reflux is performed simultaneously with the initial microwave digestion and complexation reaction using an integrated multi-stage reflux condenser. This integrated multi-stage reflux condenser is commercially available.
[0047] By employing an integrated multi-stage condensation and reflux device to perform reflux treatment simultaneously with the complexation reaction, it is possible to collect HF molecules that physically volatilize before the complexation reaction is completed and under extreme conditions, ensuring that fluorine is effectively retained.
[0048] By adopting the above-mentioned integrated multi-stage condensation reflux device, it is beneficial to improve the HF recovery efficiency, for example, the HF recovery efficiency can be ≥99.8%.
[0049] In some alternative implementations, after the complexation reaction is completed, the mixture is allowed to cool naturally to room temperature. Then, the entire reaction solution is transferred to a volumetric device, and the inner wall of the digestion vessel and the integrated multi-stage reflux condenser are washed multiple times with ultrapure water. The washing solutions are combined, and finally, the volume is adjusted to the mark and shaken well for later use.
[0050] In some alternative implementations, detection is performed using a high-resolution inductively coupled plasma mass spectrometer equipped with a collision reaction cell.
[0051] For example, a high-resolution inductively coupled plasma mass spectrometer (ICP-MS) equipped with a collision reaction cell (ORS) was used to analyze the diluted sample solution. Isotope detected: F (m / z = 19).
[0052] In some alternative implementations, a standard mode or a kinetic discrimination mode is used, and the built-in interference correction equation of the instrument software is used to eliminate interference to F; then, the external standard method or the standard addition method is used for quantitative analysis.
[0053] For example, by using the standard mode or kinetic energy discrimination (KED) mode and utilizing the instrument software's built-in interference correction equations, the interference can be eliminated. 238 U 2+ Pairs of atoms or ions 19 F + Potential interference.
[0054] Using the method provided by this invention, the recovery rate of F can reach 98.7 ± 1.2% (n = 6) in the concentration range of 0.5 ppm to 50 ppm.
[0055] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0056] Example 1 This embodiment provides a method for detecting fluorine in nickel-cobalt-manganese hydroxide, including the following steps: S1: Accurately weigh 0.5g (±1mg) of nickel-cobalt-manganese hydroxide powder (Ni 0.6 Co 0.1 Mn 0.3 (OH)₂) was uniformly mixed with 1g of boric acid flux and placed in a composite sealed digestion system (a digestion vessel made of PTFE and carbon fiber laminate). 5mL of concentrated nitric acid (65%) and 1mL of hydrofluoric acid (40%) were injected stepwise via an automatic dispensing system. The digestion vessel was immediately sealed and placed in a microwave digester. The microwave digestion program was started, and the integrated multi-stage reflux condenser was simultaneously activated. The temperature was initially raised to 80°C at a rate of 5°C / min and held for 20min for preliminary microwave digestion. Subsequently, while maintaining the temperature at 80°C, 2mL of aluminum nitrate solution was slowly injected via a high-pressure injection pump, and the temperature was raised to 150°C at a rate of 5°C / min and held for 20min for a complexation reaction.
[0057] S2: Volume Adjustment and Transfer After the complexation reaction is complete, cool to room temperature; transfer the entire resulting reaction solution to a 100 mL plastic volumetric flask. Rinse the digestion vessel and the inner wall of the integrated multi-stage reflux condenser with ultrapure water several times and carefully, adding the washings to the volumetric flask. Finally, dilute to the mark and mix well.
[0058] S3: Uses high-resolution ICP-MS (Agilent 7900, equipped with ORS) 4 Data was collected and measured at m / z=19 in the collision pool.
[0059] S4: Using the standard mode and utilizing the instrument software's built-in interference correction equation to eliminate... 238 U 2+ Pairs of atoms or ions 19 F + Potential interferences were identified; external standard method was used for quantitative analysis.
[0060] Example 2 This embodiment provides a method for detecting fluorine in nickel-cobalt-manganese hydroxide (same as in Example 1), including the following steps: S1: Accurately weigh 0.1g (±1mg) of nickel-cobalt-manganese hydroxide powder and mix it evenly with 1g of boric acid flux. Place the mixture in a composite sealed digestion system (a digestion vessel made of PTFE and carbon fiber laminate). Inject 3mL of concentrated nitric acid (65%) and 0.5mL of hydrofluoric acid (40%) in steps using an automatic liquid addition system. Immediately seal the digestion vessel and place it in a microwave digestion apparatus. Start the microwave digestion program and simultaneously turn on the integrated multi-stage reflux condenser. First, heat the mixture to 60°C at a rate of 3°C / min and maintain the temperature for 20min for preliminary microwave digestion. Then, while maintaining the temperature at 60°C, slowly inject 1mL of aluminum nitrate solution using a high-pressure injection pump. Heat the mixture to 120°C at a rate of 3°C / min and maintain the temperature for 30min for the complexation reaction.
[0061] S2: Volume Adjustment and Transfer After the complexation reaction is complete, cool to room temperature; transfer the entire resulting reaction solution to a 100 mL plastic volumetric flask. Rinse the digestion vessel and the inner wall of the integrated multi-stage reflux condenser with ultrapure water several times and carefully, adding the washings to the volumetric flask. Finally, dilute to the mark and mix well.
[0062] S3: Uses high-resolution ICP-MS (Agilent 7900, equipped with ORS) 4 Data was collected and measured at m / z=19 in the collision pool.
[0063] S4: Employs kinetic energy discrimination (KED) mode and utilizes the instrument software's built-in interference correction equation to eliminate... 238 U 2+ Pairs of atoms or ions19 F + Potential interferences were identified; quantitative analysis was performed using the standard addition method.
[0064] Example 3 This embodiment provides a method for detecting fluorine in nickel-cobalt-manganese hydroxide (same as in Example 1), including the following steps: S1: Accurately weigh 0.3g (±1mg) of nickel-cobalt-manganese hydroxide powder and mix it evenly with 1g of boric acid flux. Place the mixture in a composite sealed digestion system (a digestion vessel made of PTFE and carbon fiber laminate). Inject 7mL of concentrated nitric acid (65%) and 2mL of hydrofluoric acid (40%) in steps using an automatic liquid addition system. Immediately seal the digestion vessel and place it in a microwave digestion apparatus. Start the microwave digestion program and simultaneously turn on the integrated multi-stage reflux condenser. First, heat the mixture to 100°C at a rate of 8°C / min and hold for 15min for preliminary microwave digestion. Then, while maintaining the temperature at 100°C, slowly inject 3mL of aluminum nitrate solution using a high-pressure injection pump. Heat the mixture to 180°C at a rate of 8°C / min and hold for 10min for the complexation reaction.
[0065] S2: Volume Adjustment and Transfer After the complexation reaction is complete, cool to room temperature; transfer the entire resulting reaction solution to a 100 mL plastic volumetric flask. Rinse the digestion vessel and the inner wall of the integrated multi-stage reflux condenser with ultrapure water several times and carefully, adding the washings to the volumetric flask. Finally, dilute to the mark and mix well.
[0066] S3: Uses high-resolution ICP-MS (Agilent 7900, equipped with ORS) 4 Data was collected and measured at m / z=19 in the collision pool.
[0067] S4: Same as Example 1.
[0068] Comparative Example 1 The difference between this comparative example and Example 1 is that the sealed digestion system uses a digestion vessel made of traditional PTFE material.
[0069] Comparative Example 2 The difference between this comparative example and Example 1 is that in S1, concentrated nitric acid, hydrofluoric acid and aluminum nitrate solution are added to the composite sealed digestion system at the same time, and then the temperature is increased to 150°C at a rate of 3°C / min and kept at that temperature for 20min.
[0070] Comparative Example 3 The difference between this comparative example and Example 1 is that boric acid, a fluxing agent, was not added in S1.
[0071] Comparative Example 4 The difference between this comparative example and Example 1 is that in S1, the initial microwave digestion temperature is 50°C.
[0072] Comparative Example 5 The difference between this comparative example and Example 1 is that in S1, the initial microwave digestion temperature is 105°C.
[0073] Comparative Example 6 The difference between this comparative example and Example 1 is that in S1, the temperature of the complexation reaction is 110°C.
[0074] Comparative Example 7 The difference between this comparative example and Example 1 is that in S1, the temperature of the complexation reaction is 190°C.
[0075] Test case (1) Taking Example 1 and Comparative Examples 1-2 as examples, after step S1 is completed, the digestion vessel is opened. The results show that the liquids of Example 1 and Comparative Example 2 are clear and transparent, while the inner wall of the lid of Comparative Example 1 has a large amount of acid mist condensation marks.
[0076] (2) Taking Example 1 as an example, a spike recovery experiment was conducted. Specifically, the spike recovery experiment included: weighing 0.2000g of nickel cobalt manganese hydroxide sample, adding a known amount of fluorine standard solution (equivalent to 50.0μg of F in the nickel cobalt manganese hydroxide sample), and then performing all steps S1 to S3 in Example 1.
[0077] Recovery rate was calculated as follows: (Total amount measured after spiking - Sample background value) / Spiked amount × 100%. The sample background value is the result obtained without the addition of a known amount of fluorine standard solution, as shown in Table 1.
[0078] In addition, spiked recovery experiments were also conducted on Examples 2-3 and Comparative Examples 1-7, and the results are shown in Table 1.
[0079] Table 1 Test Results
[0080] As can be seen from Table 1, the recovery rate of the methods provided in Examples 1-3 of this invention is close to 100%, proving that the methods provided in this application are accurate and reliable.
[0081] The recovery rate of Comparative Example 1 was extremely low, which may be due to the fact that the digestion vessel made of ordinary PTFE material used in Comparative Example 1 resulted in severe F volatilization.
[0082] The recovery rate of Comparative Example 2 was also low, which may be because in Comparative Example 2, concentrated nitric acid, hydrofluoric acid and aluminum nitrate solution were added at the same time in S1, resulting in improper timing of complexation, and some F was lost or side reactions occurred.
[0083] The improper conditions set in comparative examples 3 to 7 also led to low recovery rates of F and poor accuracy of the results.
[0084] In summary, the detection method provided by this invention has at least the following advantages: (1) Extremely high fluorine recovery rate and anti-volatilization capability: By adopting a composite sealed digestion system and an integrated multi-stage condensation reflux module to act as a physical barrier, and combined with the chemical fixation effect of complexation reaction to inhibit volatilization, the problem of fluorine volatilization loss is effectively solved and improved.
[0085] (2) Excellent accuracy and reproducibility: Fluorine is stabilized in a uniform chemical form (AlF6) through complexation technology. 3- In this process, the uncertainty of pretreatment is reduced; combined with the optimized ICP-MS detection procedure, matrix interference is effectively eliminated, and good reproducibility (RSD<2%) is demonstrated among different personnel and laboratories.
[0086] (3) High efficiency and low detection limit: This invention achieves integrated sample digestion and fluorine retention, eliminating the need for subsequent cumbersome steps such as distillation and separation, and significantly reducing the pretreatment time for a single sample to less than 1 hour. The detection limit (LOD) of this method can reach 0.5 ppb, and the quantitation limit (LOQ) can reach 2 ppb, meeting the process control requirements for F content <10 ppm or even lower.
[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for detecting fluorine in a nickel-cobalt-manganese hydroxide, characterized by, The method comprises the following steps: The nickel-cobalt-manganese hydroxide is mixed with a fluxing agent, and then subjected to preliminary microwave digestion with concentrated nitric acid and hydrofluoric acid in a composite sealed digestion system, and then subjected to complexation reaction with an aluminum nitrate solution; after the complexation reaction, the obtained reaction solution is subjected to ICP-MS detection.
2. The detection method according to claim 1, characterized in that, The mass ratio of the nickel-cobalt-manganese hydroxide to the fluxing agent is 0.1:1 to 0.5:
1. Preferably, the fluxing agent comprises boric acid.
3. The method of claim 1, wherein, The dosage ratio of the nickel-cobalt-manganese hydroxide to the concentrated nitric acid is (0.1g-0.5g):(3mL-7mL). And / or, the dosage ratio of the nickel-cobalt-manganese hydroxide to the hydrofluoric acid is (0.1g-0.5g):(0.5mL-2mL). Preferably, the concentration of the concentrated nitric acid is 62%-68%. And / or, the concentration of the hydrofluoric acid is 38%-42%.
4. The method of claim 1, wherein, The preliminary microwave digestion is performed at 60-100℃ for 15-20min.
5. The method of claim 1, wherein, The dosage ratio of the nickel-cobalt-manganese hydroxide to the aluminum nitrate solution is (0.1g-0.5g):(1mL-3mL). Preferably, the concentration of the aluminum nitrate solution is 5%-15%.
6. The method of claim 1, wherein The complexation reaction is performed at a rate of 3-8℃ / min to 120-180℃, and then the temperature is kept for 10-30min.
7. The assay of any one of claims 1 to 6, wherein, The composite sealed digestion system is a digestion tank obtained by laminating PTFE and carbon fibers.
8. The assay of any one of claims 1 to 6, wherein, The integrated multi-stage condensation reflux device is used for refluxing at the same time of the preliminary microwave digestion and the complexation reaction.
9. The assay of any one of claims 1 to 6, wherein, The detection is performed by using a high-resolution inductively coupled plasma mass spectrometer equipped with a collision reaction cell.
10. The assay of any one of claims 1 to 6, wherein the assay is a competitive assay. The standard mode or kinetic energy discrimination mode is used, and the interference correction equation built in the instrument software is used to eliminate the interference on F; then the external standard method or standard addition method is used for quantitative analysis.