Spectrophotometric detection method for lanthanum-alizarin complexing ketone of fluorine element in tantalum-niobium material

Abstract

The invention provides a lanthanum-alizarin complex ketone spectrophotometric detection method for fluorine in a tantalum-niobium material, and relates to the technical field of element content detection.The method comprises the steps that 1, a lanthanum-alizarin complex ketone reagent is prepared; step 2, performing three-section gradient temperature control high-temperature hydrolysis on the tantalum-niobium material so as to release all-form fluorine; step 3, taking a ternary composite alkaline absorption liquid as a fluorine element absorption liquid, taking a lanthanum-alizarin complexing ketone reagent as a color developing agent, carrying out color developing reaction on fluorine escaped from the tantalum-niobium material after high-temperature hydrolysis, and carrying out absorbance determination; 4, carrying out a chromogenic reaction by using a fluorine standard solution and a lanthanum-alizarin complexing ketone reagent, and carrying out absorbance determination to obtain a standard working curve; and step 5, calculating the content of the fluorine element in the tantalum-niobium material according to the absorbance and the standard working curve obtained by measuring the tantalum-niobium material. According to the scheme, the detection accuracy of the fluorine content in the tantalum-niobium material can be improved by improving the release efficiency of all-form fluorine.

Description

Technical Field

[0001] The present invention relates to the technical field of elemental content analysis and detection, and particularly to a spectrophotometric detection method for fluorine element in tantalum-niobium materials using lanthanum-alizarin complexone. Background Art

[0002] As key industrial raw materials, the purity of tantalum / niobium materials plays a decisive role in product performance and application scope. As one of the common impurities in tantalum / niobium materials, the control of fluorine element content is crucial for improving the quality of tantalum / niobium materials. In tantalum / niobium materials, an appropriate amount of fluorine can enhance their corrosion resistance and electrical conductivity, which helps to expand the application scenarios of tantalum / niobium materials; however, excessive fluorine will cause the performance of tantalum / niobium materials to deteriorate, affecting their application effect and service life.

[0003] Traditional methods for determining fluorine content are usually high-temperature hydrolysis-ion chromatography coupling method, that is, under an argon atmosphere at 1200 °C, the fluorine-containing sample is hydrolyzed at high temperature into hydrogen fluoride gas, and after being trapped by an absorption solution, ion chromatography is used for quantitative analysis to determine the fluorine content. Although the detection limit of this method is as low as 0.05 ppm and is suitable for the detection of ultra-pure samples, this method has a high dependence on equipment and requires the equipped with high-temperature hydrolysis device and ion chromatography. More importantly, it cannot distinguish bound fluorine, and the release efficiency of strongly chemically bonded fluorine such as Ta-F (tantalum-fluorine), Nb-F (niobium-fluorine) is less than 60%, resulting in a systematic low detection result. Summary of the Invention

[0004] In view of this, in view of the above deficiencies, it is necessary to propose a spectrophotometric detection method for fluorine element in tantalum-niobium materials to improve the detection accuracy of fluorine content in tantalum-niobium materials by increasing the release efficiency of total-form fluorine.

[0005] The present invention provides a spectrophotometric detection method for fluorine element in tantalum-niobium materials, including the following steps:

[0006] Step 1: Prepare lanthanum-alizarin complexone reagent;

[0007] Step 2: Perform high-temperature hydrolysis on tantalum-niobium materials with three-stage gradient temperature control to release total-form fluorine; among them, the temperatures of the three stages in the three-stage gradient temperature control gradually increase to desorb fluorine in the first stage, weakly bonded fluorine in the second stage, and strongly bonded fluorine in the third stage;

[0008] Step 3: Use a ternary composite alkaline absorption solution as the fluorine element absorption solution and lanthanum-alizarin complexone reagent as the chromogenic agent to perform a chromogenic reaction on the fluorine released from tantalum-niobium materials after high-temperature hydrolysis, and measure the absorbance;

[0009] Step 4: Perform a color reaction using a fluorine standard solution and a lanthanum-alizarin complexone reagent, and measure the absorbance to obtain a standard working curve;

[0010] Step 5: Calculate the fluorine element content in the tantalum-niobium material based on the absorbance measured for the tantalum-niobium material and the standard working curve.

[0011] Preferably, step 1 specifically includes:

[0012] S11: Add deionized water to the weighed anhydrous sodium acetate, and after it is fully dissolved, add glacial acetic acid and mix them evenly;

[0013] S12: Add ammonia water to the weighed alizarin indicator, and after it is fully dissolved, add a certain amount of ammonium acetate;

[0014] S13: Add a certain amount of hydrochloric acid to the weighed lanthanum trioxide, and warm it to dissolve until it is clear;

[0015] S14: Uniformly mix the reagent dissolved in step S12 with the reagent dissolved in step S11, add a certain amount of acetone, and then uniformly mix the mixed solution with the lanthanum trioxide solution dissolved in step S13 to obtain a lanthanum-alizarin complexone reagent.

[0016] Preferably, the pH value of the prepared lanthanum-alizarin complexone reagent is 3.5 - 6.5.

[0017] Preferably, step 2 specifically includes:

[0018] S21: Uniformly place the weighed tantalum-niobium material in a clean porcelain boat, and turn on the power supply and the heating power supply of the steam generator;

[0019] S22: After connecting the lower end of the straight condenser to the ternary composite alkaline absorbent solution, raise the temperature of the resistance furnace to the first temperature range and stabilize for the first preset duration to achieve desorption of fluorine;

[0020] S23: After the first preset duration, further raise the temperature of the resistance furnace to the second temperature range and stabilize for the second preset duration to achieve weakly bonded fluorine;

[0021] S24: After the second preset duration, further raise the resistivity to the third temperature range and stabilize for the third preset duration to achieve strongly bonded fluorine.

[0022] Preferably, the first temperature range is 420°C - 460°C, the second temperature range is 810°C - 850°C, the third temperature range is 1010°C - 1020°C, the first preset duration is 3 min - 5 min, the second preset time is 3 min - 5 min, and the third preset duration is 8 min - 12 min.

[0023] Preferably, during the high-temperature hydrolysis process in step S2, the tantalum-niobium material is gradually heated in an argon gas stream containing water vapor to convert it into tantalum oxide and niobium oxide, and to cause the fluorine in the tantalum-niobium material to escape in the form of hydrogen fluoride gas, which is absorbed by the ternary composite alkaline absorbent after being filtered through a filter membrane.

[0024] Preferably, the ternary composite alkaline absorbent is composed of a 10% - 15% sodium hydroxide solution and a 0.01% - 0.2% phenolphthalein indicator; and a PTFE hydrophobic membrane is used as the filter membrane, wherein the pore size of the PTFE hydrophobic membrane is 0.1μm - 0.45μm.

[0025] Preferably, during the high-temperature hydrolysis process in step S2, the water temperature of the water vapor generating flask is controlled between 90°C and 100°C, the water vapor partial pressure is controlled in the range of 0.1 atm - 0.3 atm, and the flow rate of the argon gas stream is controlled at 30 mL / min - 100 mL / min.

[0026] Preferably, step 3 specifically includes:

[0027] S31: Dilute the ternary composite alkaline absorbent that has absorbed hydrogen fluoride gas;

[0028] S32: Take aliquots of the ternary composite alkaline absorbent that has absorbed hydrogen fluoride gas into a colorimetric tube, and add acetic acid solution until the red color just fades;

[0029] S33: Add lanthanum-alizarin complexone reagent to the colorimetric tube, dilute to the mark with water, and measure the absorbance at a specific wavelength.

[0030] Preferably, step 4 specifically includes:

[0031] S41: Weigh a certain amount of sodium fluoride and dissolve it in deionized water, and dilute to the mark to obtain a fluorine standard solution;

[0032] S42: Take several aliquots of the fluorine standard solution into colorimetric tubes, add a certain amount of lanthanum-alizarin complexone reagent, dilute to the mark with water, and measure the absorbance at a specific wavelength;

[0033] S43: Draw a standard working curve based on the absorbance measurement results corresponding to each aliquot of the fluorine standard solution.

[0034] As can be seen from the above technical solutions, in the lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in the tantalum-niobium material provided by the embodiments of the present invention, first, the lanthanum-alizarin complexone reagent is prepared, and then the tantalum-niobium material is subjected to high-temperature hydrolysis with three-stage gradient temperature control to release the fluorine in all forms; further, the fluorine element is absorbed by a ternary composite alkaline absorbent, and the lanthanum-alizarin complexone reagent is used as a chromogenic agent to carry out a chromogenic reaction on the hydrogen fluoride gas evolved from the tantalum-niobium material after high-temperature hydrolysis, and the absorbance is measured; further, a standard working curve is made by carrying out a chromogenic reaction with a fluorine standard solution and the lanthanum-alizarin complexone reagent and measuring the absorbance. In this way, by comparing the absorbance measured for the tantalum-niobium material with the standard working curve, the fluorine element content in the tantalum-niobium material can be obtained. It can be seen that through the three-stage gradient temperature control high-temperature hydrolysis process, this solution can desorb fluorine in the first stage, weakly bond fluorine in the second stage, and strongly bond fluorine in the third stage, realizing the efficient release of fluorine in all forms, thereby improving the detection accuracy of the fluorine content in the tantalum-niobium material. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flowchart of a lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in a tantalum-niobium material provided by an embodiment of the present invention.

[0036] Figure 2 A standard working curve fitted by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] As Figure 1 shown, an embodiment of the present invention provides a lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in a tantalum-niobium material, including the following steps:

[0039] Step 1: Prepare a lanthanum-alizarin complexone reagent;

[0040] Step 2: Perform high-temperature hydrolysis on the tantalum-niobium material with three-stage gradient temperature control to release the fluorine in all forms; among them, the temperatures of the three stages in the three-stage gradient temperature control gradually increase to desorb fluorine in the first stage, weakly bond fluorine in the second stage, and strongly bond fluorine in the third stage;

[0041] Step 3: Use a ternary composite alkaline absorbent as the fluorine element absorbent and the lanthanum-alizarin complexone reagent as the chromogenic agent to carry out a chromogenic reaction on the fluorine evolved from the tantalum-niobium material after high-temperature hydrolysis, and measure the absorbance;

[0042] Step 4: Perform a color reaction using a fluorine standard solution and a lanthanum-alizarin complexone reagent, and measure the absorbance to obtain a standard working curve;

[0043] Step 5: Calculate the fluorine element content in the tantalum-niobium material based on the absorbance measured for the tantalum-niobium material and the standard working curve.

[0044] In this embodiment, through a three-stage gradient temperature-controlled high-temperature hydrolysis process, it is possible to desorb fluorine in the first stage, weakly bond fluorine in the second stage, and strongly bond fluorine in the third stage, achieving the efficient release of all forms of fluorine, thereby improving the detection accuracy of the fluorine content in the tantalum-niobium material. Moreover, using a ternary composite alkaline absorbent solution to absorb fluorine elements and a lanthanum-alizarin complexone reagent as a color-developing agent can reduce the competition for complexation between tantalum-niobium matrix ions and the color-developing agent, solving the problem of the falsely high absorbance in the traditional spectrophotometry method, that is, reducing the deviation of the color reaction and improving the detection result of the fluorine content.

[0045] For Step 1, when preparing the lanthanum-alizarin complexone reagent, it can be specifically achieved in the following manner:

[0046] S11: Add deionized water to the weighed anhydrous sodium acetate, fully dissolve it, then add glacial acetic acid and mix them evenly;

[0047] S12: Add ammonia water to the weighed alizarin indicator, fully dissolve it, and then add a certain amount of ammonium acetate;

[0048] S13: Add a certain amount of hydrochloric acid to the weighed lanthanum trioxide, and warm it to dissolve until it becomes clear;

[0049] S14: Uniformly mix the reagent dissolved in Step S12 with the reagent dissolved in Step S11, add a certain amount of acetone, and then uniformly mix the mixed solution with the lanthanum trioxide solution dissolved in Step S13 to obtain the lanthanum-alizarin complexone reagent.

[0050] In this embodiment, when preparing 0.5 mol / L lanthanum-alizarin complexone reagent: First step: At room temperature, add 25 g of anhydrous sodium acetate into a 1000 mL beaker, add deionized water, magnetically stir for 15 min until completely dissolved, then add 30 mL of glacial acetic acid (concentration 36%), and continue to stir for 5 - 10 min to keep the solution homogeneous. Second step: Weigh 0.35 g of alizarin indicator and add 5 mL of ammonia water, magnetically stir at room temperature for 10 - 20 min, after completely dissolving, add 5 mL of ammonium acetate (concentration 1.5 mol / L). Third step: In a beaker containing 0.20 g of lanthanum(III) oxide, add 10 mL (5 mol / L) of hydrochloric acid, warm and dissolve on a constant temperature electric furnace until clear. Finally, transfer the reagent dissolved in the second step into the first step, stir and mix evenly, add 300 mL - 500 mL of acetone, transfer it into a 1000 mL volumetric flask, and transfer the lanthanum(III) oxide solution into it as well, make up the volume to the mark and shake well, and keep the pH value of the solution at 3.5 - 6.5.

[0051] For step 2, when performing high-temperature hydrolysis with three-stage gradient temperature control on tantalum-niobium materials, it can be specifically achieved in the following way:

[0052] S21: Evenly place the weighed tantalum-niobium materials in a clean porcelain boat, and turn on the power supply and the heating power supply of the steam generator;

[0053] S22: After connecting the lower end of the straight condenser to the ternary composite alkaline absorbent solution, raise the temperature of the resistance furnace to the first temperature range and stabilize for the first preset time to achieve desorption of fluorine;

[0054] S23: After the first preset time, further raise the temperature of the resistance furnace to the second temperature range and stabilize for the second preset time to achieve weakly bonded fluorine;

[0055] S24: After the second preset time, further raise the resistivity to the third temperature range and stabilize for the third preset time to achieve strongly bonded fluorine.

[0056] In this embodiment, 0.1000 - 1.0000 g of tantalum / niobium material can be evenly placed in a clean porcelain boat. Connect the power supply and the heating power supply of the steam generating flask and turn on the control switch. After connecting the lower end of the straight condenser tube to the NaOH - phenolphthalein - ethanol ternary composite alkaline absorbent solution, first raise the temperature of the resistance furnace to 420°C - 460°C and stabilize for 3 min - 5 min to achieve desorption of fluorine; then raise the temperature of the resistance furnace from 420°C - 460°C to 810°C - 850°C and continue to stabilize for 3 min - 5 min to achieve weakly bonded fluorine; finally, continue to raise the temperature from 810°C - 850°C to 1010°C - 1020°C, and control the time within 8 min - 12 min to achieve strongly bonded fluorine, so as to achieve the efficient release of total - form fluorine. Further, the tantalum / niobium material is intercepted by a PTFE hydrophobic membrane with a pore size of 0.1 - 0.45 μm, and the total - form fluorine is absorbed by the NaOH - phenolphthalein - ethanol ternary composite alkaline absorbent solution. The water temperature of the steam generating flask is controlled between 90°C and 100°C, the steam partial pressure is controlled between 0.1 atm and 0.3 atm, the steam injection rate is 0.2 - 0.5 mL / min, and the argon pressure reducing valve is adjusted to control the argon flow rate between 30 mL / min and 100 mL / min to ensure the stable escape of hydrogen fluoride gas. At the same time, turn on the cooling water.

[0057] Among them, in the hydrolysis process, 10 mL - 20 mL of deionized water can be taken, and 1 - 5 drops of the ternary composite alkaline absorbent solution are added as the fluorine element absorbent solution. Place the outlet of the high - temperature hydrolysis furnace below the liquid level of the absorbent solution, and use a sample - feeding rod to send the porcelain boat containing the high - purity tantalum / niobium material to the middle position of the high - temperature hydrolysis furnace and tighten the hollow plug. The tantalum / niobium material is gradually heated in an argon stream containing water vapor and converted into tantalum oxide or niobium oxide. The fluorine in the sample escapes in the form of hydrogen fluoride gas and is absorbed by the alkaline absorbent solution after passing through the PTFE membrane with a pore size of 0.1 - 0.45 μm to intercept the tantalum / niobium material matrix.

[0058] In this embodiment, the ternary composite alkaline absorbent solution can be composed of a 10% - 15% sodium hydroxide solution and a 0.01% - 0.2% phenolphthalein indicator; the dosage adaptation ratio of the ternary composite alkaline absorbent solution to the lanthanum - alizarin complexone reagent is 0.2:10.

[0059] For step 3, when measuring the absorbance of the tantalum - niobium material, it can be specifically achieved in the following way:

[0060] S31: Dilute the ternary composite alkaline absorbent solution that has absorbed hydrogen fluoride gas;

[0061] S32: Take aliquots of the ternary composite alkaline absorbent solution that has absorbed hydrogen fluoride gas into a colorimetric tube and add acetic acid solution until the red color just fades;

[0062] S33: Add the lanthanum-alizarin complexone reagent to the colorimetric tube, dilute to the mark with water, and measure the absorbance at a specific wavelength.

[0063] In this embodiment, after the high-temperature hydrolysis in step 2 is completed, remove the ternary composite alkaline absorbent solution, wash the ternary composite alkaline absorbent solution into a 50 mL - 100 mL volumetric flask, dilute to the mark with water, and shake well. Pipette 2 mL - 10 mL of the ternary composite alkaline absorbent solution into a 25 mL colorimetric tube, add 0.1 mol / L acetic acid solution dropwise until the red color just fades, and accurately add 10 mL (0.5 mol / L) of the lanthanum-alizarin complexone reagent. Dilute to the mark with water, shake well, and measure the absorbance at a wavelength of 620 nm after 10 min - 20 min.

[0064] For step 4, when making the standard working curve, it can be achieved in the following way:

[0065] S41: Weigh a certain amount of sodium fluoride and dissolve it in deionized water, and dilute to the mark to obtain a fluoride standard solution;

[0066] S42: Take several portions of the fluoride standard solution in a colorimetric tube respectively, add a certain amount of the lanthanum-alizarin complexone reagent, dilute to the mark with water, and measure the absorbance at a specific wavelength;

[0067] S43: Draw a standard working curve according to the absorbance measurement results corresponding to each portion of the fluoride standard solution.

[0068] In this embodiment, when preparing the fluoride standard solution, 0.2210 g of sodium fluoride (99.9%) can be weighed in a beaker, dissolved in 100 mL of deionized water, washed into a 1000 mL volumetric flask with deionized water, diluted to the mark, shaken well, and stored in a plastic bottle. 1 mL of this solution contains 100 μg of fluorine. Then take 0, 5, 10, 15, 20, 25 μg of the fluoride standard solution in a 25 mL colorimetric tube respectively, and accurately add 10 mL (0.5 mol / L) of the lanthanum-alizarin complexone reagent. Dilute to the mark with water, and measure the absorbance at a wavelength of 620 nm after 10 min - 20 min.

[0069] For example, through the above preparation process of the fluoride standard solution, a working curve y = 0.0231x + 0.0056 as shown in Figure 2 can be obtained by curve fitting.

[0070] Further, with the fluorine content as the abscissa and the absorbance as the ordinate, a curve can be plotted, and the slope of the obtained curve can be determined as the absorbance value A per microgram of fluorine content. Alternatively, for each aspiration volume, divide the corresponding absorbance by the fluorine content to obtain the absorbance value per microgram of fluorine content for the corresponding aspiration volume, and calculate the average value corresponding to each aspiration volume to obtain the absorbance value per microgram of fluorine content. If the calculation result of A in the above manner is 0.023 / μg - 0.026 / μg, then its average value 0.0245 / μg can be taken for use in calculating the fluorine element content in the tantalum-niobium material in step 5.

[0071] For step 5, consider calculating the fluorine element content in the tantalum-niobium material based on the absorbance measured from the tantalum-niobium material and the standard working curve. Specifically, the fluorine element content in the tantalum-niobium material is calculated through the following calculation formula:

[0072]

[0073] Where: A1 is the absorbance value of the fluorine amount in the tantalum-niobium material obtained from the spectrophotometer, A0 is the system blank absorbance, A is the absorbance value of the fluorine content per microgram of tantalum-niobium material calculated through the standard working curve in step 4, m is the weighed sample amount of the tantalum-niobium material, with the unit of g, V1 is the volume of the aliquoted test solution, with the unit of mL, and V0 is the total volume of the test solution, with the unit of mL.

[0074] The effects of this solution will be further described below in combination with specific experimental results.

[0075] The experimental results of the tantalum-niobium rejection rate and the relative deviation of the color development stability are shown in Table 1 and Table 2 below:

[0076] Table 1 Rejection Rate Test (ICP-MS)

[0077]

[0078] Table 2 Relative Deviation of Color Development Stability

[0079]

[0080]

[0081] As can be seen from Table 1 and Table 2, the matrix interference has been eliminated. In this solution, a ternary composite alkaline absorbent of NaOH - phenolphthalein - ethanol is designed, integrating the PTFE hydrophobic membrane filtration technology, so that the retention rate of matrix metal ions > 99.5%, and the color reaction deviation ≤ ±0.5%. The content of tantalum or niobium in the ternary composite alkaline absorbent of NaOH - phenolphthalein - ethanol is detected by an inductively coupled plasma emission spectrometer (ICP - MS) to judge whether there is residue of tantalum or niobium matrix, and then the retention rate of tantalum - niobium matrix is calculated. The results show that with the PTFE hydrophobic membrane filtration adopted, the retention rate of tantalum - niobium matrix > 99.5%, and the color reaction deviation ≤ ±0.5%.

[0082] Among them, the retention rate in Table 1 is calculated by the following formula:

[0083]

[0084] C is the residual concentration of tantalum - niobium material in the absorbent (μg / mL), and C0 is the initial concentration (μg / mL) of 0.1000 - 1.0000 g of tantalum - niobium material made up to 50 mL - 100 mL in volume.

[0085] Table 3 and Table 4 show the overall fluoride spike recovery under one - stage temperature control and three - stage temperature control respectively.

[0086] Table 3 Overall fluoride spike recovery under one - stage temperature control

[0087]

[0088] Table 4 Overall fluoride spike recovery under three - stage temperature control

[0089]

[0090] From the fluoride spike recovery experiments in Table 3 and Table 4 above, it can be seen that when using one - stage temperature control for sample hydrolysis at a fixed high temperature, the fluoride recovery rate is about 78% - 85%. This is because some fluorides cannot be completely hydrolyzed at a single high temperature, resulting in not all fluorine elements being converted into detectable ionic forms. When using three - stage temperature control, through the optimization of different temperature stages, the fluoride recovery rate is increased to more than 95%. In the first low - temperature stage, some easily hydrolyzable fluorides start to decompose first; in the second medium - temperature stage, more fluorides are hydrolyzed; in the third high - temperature stage, the difficult - to - hydrolyze fluorides are also fully decomposed, ultimately leading to a significant increase in the overall recovery rate.

[0091] The reagents used above are required to be as follows: anhydrous sodium acetate: CH3COONa, analytical pure; acetic acid: 0.1 mol / L, 1 mol / L solution; ammonium acetate: CH3COONH4, 1.5 mol / L; lanthanum sesquioxide: La2O3, analytical pure; hydrochloric acid: 2 mol / L, guaranteed reagent grade; acetone: C3H6O, analytical pure; sodium hydroxide: guaranteed reagent grade, 10 g / L solution; phenolphthalein indicator: 1 g / L ethanol solution; fluorine standard solution: 10 g / mL; ammonia water: NH3·H2O, 25%; argon: purity not less than 99.99%.

[0092] In summary, the lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials provided by this solution has at least the following beneficial effects:

[0093] (1) High-efficiency release of total fluorine forms

[0094] In the traditional solution, high-temperature hydrolysis can only release weakly bonded fluorine (such as adsorbed state), and the release efficiency of strongly chemically bonded fluorine such as Ta-F and Nb-F is less than 60%. However, through the three-stage gradient temperature control provided by this solution, the decomposition thresholds of fluorine with different bond energies can be accurately matched. At the same time, the dynamic regulation of water vapor partial pressure enhances the escape power of hydrogen fluoride gas, resulting in an increase in the release efficiency of total fluorine forms. Moreover, it has been verified that the release rate of fluorine using this solution can reach 98%. If only a single-stage treatment at 1000 °C is used, the fluorine release rate is reduced to 82%. If water vapor injection is cancelled, the release rate will be further reduced to <70%.

[0095] (2) Cost-performance balance

[0096] In the traditional solution, the cost is high. For example, the ion chromatography equipment used is usually more than 1 million yuan, and the cost of reagents and consumables for a single detection is about 245 yuan, and the time-consuming is more than 6 hours, which is difficult to meet the requirements of industrial batch detection. However, in this application, by combining the high-temperature hydrolysis module with a microscale colorimetric system (the dosage of lanthanum-alizarin complexone reagent is 10 mL / sample), the comprehensive cost per sample is compressed to 35 yuan. At the same time, through the integrated design of the high-temperature hydrolysis and spectrophotometry modules, the hardware investment is reduced by more than 50%, and the detection cycle is also shortened to 1 hour / sample.

[0097] (3) Wide-range adaptive detection

[0098] In the traditional solution, the upper limit of ion chromatography is 50 ppm. High-fluoride samples need to be diluted multiple times, and at the same time, an accumulation error of more than 5% will occur. In this application, through a hierarchical color development strategy, the low-concentration mode is 0.1 ppm to 200 ppm, and the high-concentration mode is 200 ppm to 15,000 ppm. By adjusting the amount of tantalum-niobium material weighed and the amount of aliquoted absorbent, the dosage of the color developer can be automatically calibrated, so as to achieve seamless detection in a wide range of 0.1 ppm to 15,000 ppm. At the same time, the linear error can be ≤ ±1.5% (R 2 = 0.9995).

[0099] (4) Improvement in anti-interference ability

[0100] In the traditional solution, tantalum ions and niobium ions in the absorbent will form colloids, interfering with the color development reaction. In this solution, a ternary composite alkaline absorbent, that is, a NaOH-phenolphthalein-ethanol solution system, is used, and at the same time, PTFE membrane filtration is used, which can make the matrix metal interception rate > 99.5%.

[0101] (5) Improvement in operation convenience

[0102] The traditional solution requires professional chromatography operators and complex equipment maintenance. In this solution, the high-temperature hydrolysis chamber and the gas absorption module are integrally encapsulated, and stable collection of hydrogen fluoride gas can be achieved with one key, modular maintenance, and it only takes < 5 minutes to replace the PTFE membrane.

[0103] The modules or units in the device of the embodiment of the present invention can be combined, divided, and deleted according to actual needs. The above disclosure is only the preferred embodiment of the present invention. Of course, the scope of the rights of the present invention cannot be limited by this. Those of ordinary skill in the art can understand all or part of the processes of the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. A lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials, characterized in that, It includes the following steps: Step 1: Prepare the lanthanum-alizarin complexone reagent; Step 2: Perform high-temperature hydrolysis on the tantalum-niobium material with three-stage gradient temperature control to release total-form fluorine; among them, the temperatures of the three stages in the three-stage gradient temperature control gradually increase to desorb fluorine in the first stage, weakly bond fluorine in the second stage, and strongly bond fluorine in the third stage; Step 3: Use the ternary composite alkaline absorbent as the fluorine element absorbent and the lanthanum-alizarin complexone reagent as the chromogenic agent to perform a chromogenic reaction on the fluorine escaping from the tantalum-niobium material after high-temperature hydrolysis, and perform absorbance measurement; Step 4: Use the fluorine standard solution and the lanthanum-alizarin complexone reagent to perform a chromogenic reaction and perform absorbance measurement to obtain the standard working curve; Step 5: Calculate the fluorine element content in the tantalum-niobium material according to the absorbance measured for the tantalum-niobium material and the standard working curve.

2. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials according to claim 1, characterized in that, The specific steps of Step 1 include: S11: Add deionized water to the weighed anhydrous sodium acetate, fully dissolve it, then add glacial acetic acid and mix them evenly; S12: Add ammonia water to the weighed alizarin indicator, fully dissolve it, and then add a certain amount of ammonium acetate; S13: Add a certain amount of hydrochloric acid to the weighed lanthanum trioxide and warm it to dissolve until it is clear; S14: Uniformly mix the reagent dissolved in Step S12 with the reagent dissolved in Step S11, add a certain amount of acetone, and then uniformly mix the mixed solution with the lanthanum trioxide solution dissolved in Step S13 to obtain the lanthanum-alizarin complexone reagent.

3. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials according to claim 2, characterized in that, The pH value of the prepared lanthanum-alizarin complexone reagent is 3.5 - 6.

5.

4. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium material according to claim 1, wherein The specific steps of Step 2 include: S21: Uniformly place the weighed tantalum-niobium material in a clean porcelain boat, and turn on the power supply and the heating power supply of the steam generating bottle; S22: After connecting the lower end of the straight condenser to the ternary composite alkaline absorbent, raise the temperature of the resistance furnace to the first temperature range and stabilize for the first preset time to desorb fluorine; S23: After the first preset time, further raise the temperature of the resistance furnace to the second temperature range and stabilize for the second preset time to weakly bond fluorine; S24: After the second preset time, further raise the resistivity to the third temperature range and stabilize for the third preset time to strongly bond fluorine.

5. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials according to claim 4, characterized in that, The first temperature range is 420°C - 460°C, the second temperature range is 810°C - 850°C, the third temperature range is 1010°C - 1020°C, the first preset time is 3 min - 5 min, the second preset time is 3 min - 5 min, and the third preset time is 8 min - 12 min.

6. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials according to claim 4, characterized in that, During the high-temperature hydrolysis process of Step S2, the tantalum-niobium material is gradually heated in an argon gas stream containing water vapor to convert it into tantalum oxide and niobium oxide, and the fluorine in the tantalum-niobium material escapes in the form of hydrogen fluoride gas and is absorbed by the ternary composite alkaline absorbent after being filtered by the filter membrane.

7. The spectrophotometric detection method of fluorine element in tantalum-niobium materials according to claim 6, characterized in that, The ternary composite alkaline absorbent is composed of a 10% - 15% sodium hydroxide solution and a 0.01% - 0.2% phenolphthalein indicator; and a PTFE hydrophobic membrane is used as the filter membrane, where the pore size of the PTFE hydrophobic membrane is 0.1 μm - 0.45 μm.

8. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials according to claim 6, characterized in that, During the high-temperature hydrolysis process in step S2, the water temperature in the steam generation flask is controlled between 90°C and 100°C, the steam partial pressure is controlled in the range of 0.1 atm to 0.3 atm, and the flow rate of the argon gas stream is controlled between 30 mL / min and 100 mL / min.

9. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials according to claim 6, characterized in that, The specific steps of step 3 are as follows: S31: Dilute the ternary composite alkaline absorbent that has absorbed hydrogen fluoride gas. S32: Take aliquots of the ternary composite alkaline absorbent that has absorbed hydrogen fluoride gas into a colorimetric tube, and add acetic acid solution dropwise until the red color just fades. S33: Add lanthanum-alizarin complexone reagent to the colorimetric tube, dilute it to the mark with water, and measure the absorbance at a specific wavelength.

10. The lanthanum-alizarin complexone spectrophotometric detection method for fluorine element in tantalum-niobium materials according to claim 1, characterized in that, The specific steps of step 4 are as follows: S41: Weigh a certain amount of sodium fluoride and dissolve it in deionized water, then dilute it to the mark to obtain a fluoride standard solution. S42: Take several aliquots of the fluoride standard solution into colorimetric tubes respectively, add a certain amount of lanthanum-alizarin complexone reagent, dilute them to the mark with water, and measure the absorbance at a specific wavelength. S43: Draw a standard working curve based on the absorbance measurement results corresponding to each aliquot of the fluoride standard solution.

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