X-ray fluorescence spectrum detection method of manganese metal

Abstract

The invention discloses an X-ray fluorescence spectrum detection method of metal manganese, which comprises the following specific steps: step 1, pre-oxidizing a series of standard samples of metal manganese and a sample to be detected, and melting at high temperature to prepare a uniform and smooth glass sheet; 2, measuring the X-ray fluorescence intensity of the to-be-measured element in the glass sheet prepared in the step 1 by using an X-ray fluorescence spectrometer, drawing a calibration curve of the to-be-measured element according to the X-ray fluorescence intensity of the to-be-measured element and the certificate value of the element in the standard sample, and calculating the X-ray fluorescence intensity of the to-be-measured element according to the calibration curve obtained in the step 2. And calculating the mass fractions of manganese, silicon, phosphorus, iron and other components in the metal manganese sample. The method comprises the following steps: dissolving, oxidizing and evaporating a manganese metal sample by using a dilute nitric acid solution, melting lithium tetraborate as a flux and cobalt as an internal standard element of manganese at high temperature by using a high-frequency melting furnace, and melting the sample and lithium tetraborate into a flat and smooth glass sample wafer, so that the glass sample wafer meets the analysis requirements of an X-fluorescence spectrophotometer and does not damage a platinum crucible.

Description

Technical Field

[0001] The invention relates to the technical field of metal manganese content detection, and in particular to an X-ray fluorescence spectrum detection method for metal manganese. Background Art

[0002] Metallic manganese is an important alloy raw material in the steel industry. Adding an appropriate amount of metallic manganese during the steelmaking process can eliminate iron oxide and sulfide in the steel, thereby improving the purity and quality of the steel.

[0003] Conventional analysis uses the trivalent manganese-ferrous titration method (chemical analysis) for the main element manganese in metallic manganese: the sample is dissolved in nitric acid and phosphoric acid, and in the presence of a large amount of phosphoric acid, at about 200°C, divalent manganese is oxidized to trivalent manganese with perchloric acid or ammonium nitrate, and trivalent manganese is titrated with a ferrous standard solution. Perchloric acid and ammonium nitrate, as oxidants, are important explosive-making agents, and their distribution is strictly controlled. The purchasing channels are becoming increasingly narrow, and procurement is very difficult. There is a possibility of supply interruption at any time. Trace elements silicon, phosphorus, and iron are analyzed by ICP-AES (instrumental analysis). For one sample, the analysis process needs to use two methods, chemical analysis and instrumental analysis, respectively. It takes two people half a day or one person a day to complete, with high labor costs; the operation process is complicated, the analysis takes a long time, and the efficiency is low. Toxic, harmful, and explosive reagents pose safety risks.

[0004] Instrumental analysis such as X-ray fluorescence spectrometers has been widely studied and applied due to their advantages such as fast analysis speed, good stability, low detection limit, wide analysis range and simultaneous analysis of multiple elements. Pretreatment methods for X-ray fluorescence spectrometry include molten glass sheet method and powder pressing. The powder pressing method has serious mineral effect and particle size effect, large analysis error, and is rarely used in the field of relatively expensive ferroalloy analysis, especially when it involves acceptance and settlement. The molten glass sheet method can quickly and accurately analyze most components. However, for metallic manganese, the difficulty of molten glass sheets is that it is difficult to find a suitable flux to directly make a glass sheet with uniform material that meets the requirements of X-ray fluorescence spectrometer analysis with the sample, and it is also necessary to ensure that the platinum crucible is not corroded and damaged during the melting and filming process. Summary of the invention

[0005] The main purpose of the present invention is to provide an X-ray fluorescence spectrum detection method for metallic manganese, which uses a dilute nitric acid solution to dissolve, oxidize, and evaporate a metallic manganese sample, uses lithium tetraborate as a flux, and cobalt as an internal standard element of manganese, and is melted at a high temperature in a high-frequency melting furnace. The sample and lithium tetraborate are melted into a uniform, flat, and smooth glass sample, so that the glass sample meets the analysis requirements of an X-ray fluorescence spectrometer and does not damage a platinum crucible.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] Step 1: pre-oxidize a series of standard samples of metallic manganese and melt them at high temperature to form a series of standard sample glass sheets;

[0008] Step 2: Using an X-ray fluorescence spectrometer to measure the X-ray fluorescence intensity of the element to be measured in the series of standard sample glass sheets prepared in step 1, and draw a calibration curve of the element to be measured based on the X-ray fluorescence intensity of the element to be measured and the certificate value of the element in the standard sample;

[0009] Step 3: pre-oxidizing the metal manganese sample and melting it at high temperature to make a sample glass sheet;

[0010] Step 4: Use an X-ray fluorescence spectrometer to measure the X-ray fluorescence intensity of the element to be measured in the sample glass piece obtained in step 3, and calculate the mass fractions of manganese, silicon, phosphorus, iron and other components in the metallic manganese sample based on the calibration curve obtained in step 2.

[0011] Furthermore, the treatment process of step one and step three is the same, and the specific treatment process is: accurately weigh the sample and the internal standard into a platinum crucible, drip a wetting agent into the platinum crucible to wet the sample, and slowly and quantitatively add an oxidant, after the violent reaction stops, evaporate the treated sample to dryness at low temperature, and then quantitatively cover the flux thereon, quantitatively add a release agent, and melt the sample into a uniform, flat, and smooth glass sheet through a melting furnace.

[0012] Furthermore, the component ratio of the sample, internal standard, wetting agent, oxidant, flux and release agent is 0.2g:0.1g:2ml:6ml:8g:7d, and the sample is a standard metal manganese sample or a metal manganese sample to be tested.

[0013] Furthermore, the internal standard is cobalt trioxide.

[0014] Furthermore, the wetting agent is water.

[0015] Furthermore, the oxidant is (1+1) dilute hydrochloric acid.

[0016] Furthermore, the flux is lithium tetraborate.

[0017] Furthermore, the release agent is potassium bromide.

[0018] Furthermore, the temperature of the melting furnace when melting the sample is 1000 to 1100 degrees.

[0019] Furthermore, the temperature of the treated sample when evaporated to dryness at low temperature is 190 degrees to 210 degrees.

[0020] Furthermore, the preparation of the regression curve in step 2 is specifically as follows: select no less than five series of metallic manganese standard samples, make a series of standard sample glass sheets according to the processing technology in step 1, and then operate the standard sample glass sheets through an X-ray fluorescence spectrometer, establish an analysis task, an analysis procedure, measure the X-ray fluorescence intensity, perform curve regression with the MVR function, and establish a calibration curve for each element.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention utilizes a dilute nitric acid solution to dissolve, oxidize, and evaporate a metallic manganese sample, uses lithium tetraborate as a flux, and cobalt as an internal standard element of manganese, and is melted at high temperature in a high-frequency melting furnace. The sample and lithium tetraborate are melted into a flat and smooth glass sample, so that the glass sample meets the analysis requirements of an X-ray fluorescence spectrometer and does not damage the crucible. The mass fractions of components such as manganese, silicon, phosphorus, and iron in the sample are calculated based on the calibration curve and the measured X-ray fluorescence intensity, based on the principle that the intensity of the characteristic spectral lines of each element is proportional to the content.

[0023] 2. The present invention treats the sample with nitric acid, adds lithium tetraborate flux to melt and prepares a glass sample, and uses X-ray fluorescence spectrometer to analyze. The curve has good linearity. The relative standard deviation RSD% (n=3) of the measurement results is 0.092 for manganese, 2.34 for silicon, 3.46 for phosphorus, and 1.28 for iron. The method has high precision. The measurement results are consistent with the certificate value and the measurement results of the chemical titration method ICP-AES method, and the results are accurate and reliable. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0025] Embodiment 1:

[0026] A method for detecting metal manganese by X-ray fluorescence spectrum, comprising the following steps:

[0027] Step 1: pre-oxidize a series of standard samples of metallic manganese and melt them at high temperature to form a series of standard sample glass sheets;

[0028] Step 2: Use an X-ray fluorescence spectrometer to measure the standard sample glass sheet in step 1 to obtain the fluorescence X-ray intensity of various elements in the standard sample. According to the fact that the fluorescence X-ray intensity of an element is proportional to the content of the element in the sample, draw a working curve for each element.

[0029] Step 3: pre-oxidizing the metal manganese sample and melting it at high temperature to make a sample glass sheet;

[0030] Step 4: Use an X-ray fluorescence spectrometer to measure the sample glass sheet obtained in step 3, calculate the sample according to the working curve obtained in step 2, and obtain the contents of manganese, silicon, phosphorus, iron and other components in the metal manganese to be tested.

[0031] Among them, the processing technology of step one and step three is the same, and the specific processing technology is: accurately weigh the sample and the internal standard into a platinum crucible, drip a wetting agent into the platinum crucible to wet the sample, and slowly and quantitatively add an oxidant, after the violent reaction stops, evaporate the treated sample to dryness at low temperature, and then quantitatively cover the flux thereon, quantitatively add a release agent, and melt the sample into a uniform, flat and smooth glass sheet through a melting furnace.

[0032] The component ratio of the sample, internal standard, wetting agent, oxidant, flux and release agent is 0.2g:0.1g:2ml:6ml:8g:7d, and the sample is a standard metal manganese sample or a metal manganese sample to be tested.

[0033] The internal standard is cobalt trioxide.

[0034] Wherein, the wetting agent is water.

[0035] Wherein, the oxidant is (1+1) dilute hydrochloric acid.

[0036] Wherein, the flux is lithium tetraborate.

[0037] Wherein, the release agent is potassium bromide.

[0038] Wherein, the temperature of the melting furnace when melting the sample is 1000 degrees to 1100 degrees.

[0039] The temperature of the treated sample when evaporated to dryness at low temperature is 190 to 210 degrees.

[0040] Among them, the preparation of the regression curve in step 2 is specifically as follows: a series (not less than five) of standard metal manganese samples with a certain gradient are selected, and standard glass sheets are made according to the processing technology in step 1, and then the standard glass sheets are operated through an X-ray fluorescence spectrometer, and an analysis task is established, an analysis procedure is performed, and the X-ray fluorescence intensity is measured, and a curve regression is performed with the MVR function to establish a calibration curve for each element.

[0041] Embodiment 2:

[0042] Taking the standard sample of manganese metal GSB03-2470-2008 (sample 1) and the daily analysis sample of manganese metal (sample 2) as examples, this measurement method is used to measure the contents of manganese, silicon, phosphorus, iron and other components. The specific measurement process and results are as follows:

[0043] a) Instrument and main working parameters:

[0044] ZSXPrimusIII+ X-ray fluorescence spectrometer (Rigaku, Japan) and its operating parameters are shown in Table 1:

[0045] Table 1 X-ray fluorescence spectrometer operating parameters

[0046]

[0047] Analymate high frequency melting furnace (Beijing Jingyuan Century Technology Co., Ltd.) and its high frequency melting furnace working parameters:

[0048] First heat time: 60s; First heat temperature: 650℃; Second heat time: 60s; Second heat temperature: 850℃; Melting time: 540s; Melting temperature 1050℃; Self-cooling time: 150s; Wind cooling time: 150s; Swing amplitude: 3000; Swing speed: 25; Spin speed: 1000; First inversion amplitude: 5500; Second inversion amplitude: 5800; Second inversion speed: 6500.

[0049] b) Preparation of glass sample by melting samples: Weigh 0.2000g (accurate to 0.0001g) sample and 0.1000g (accurate to 0.0001g) cobalt trioxide into a platinum crucible, drip 2ml water to moisten the sample, slowly add 6ml (1+1) nitric acid, and after the violent reaction stops, place it on a heating plate and evaporate to dryness at low temperature (200±10℃). Cover it with 8.0000g (accurate to 0.0002g) lithium tetraborate and 7d potassium bromide (30%) as a release agent, and melt it in a high-frequency melting furnace with the working parameters of 1050℃ to prepare a glass sample.

[0050] c) Working curve

[0051] Seven standard samples including NMn-1, GSB03-2470-2008, YSBC28672-2020, YSBC15603-2008, ALYR43004, 78X43004TG and high-purity manganese were dissolved-melted in the same manner as the test samples to prepare glass samples, and a working curve was established on an X-ray fluorescence spectrometer using the parameter conditions in Table 1 (the manganese curve was established using cobalt as the internal standard).

[0052] The linear range of the working curve, linear regression equation, correlation coefficient and accuracy are shown in Table 2.

[0053] Table 2 Linear range of working curve, linear regression equation, correlation coefficient and accuracy

[0054]

[0055] As shown in Table 2, the linear correlation and accuracy of the calibration curve are good.

[0056] d) Precision of the method

[0057] According to the test method, three glass samples were melted for sample 1 and measured by X-ray fluorescence spectrometer. The results were calculated by the working curve established above, and the relative standard deviation of the three measurement results was calculated. The results of the three measurements and the relative standard deviation of each element are shown in Table 3.

[0058] Table 3 Results of three measurements and relative standard deviations;

[0059]

[0060]

[0061] e) Sample measurement results

[0062] Sample 1 and sample 2 were tested under the instrument working conditions. Sample 1 is a standard substance, and its certificate value and measured value are shown in Table 4. Sample 2 is a routine analysis sample, and the results of manganese content determination by conventional method - ammonium nitrate ferrous oxide titration method, silicon, phosphorus and iron content determination by ICP-AES method and the results of detection by this method are also shown in Table 4.

[0063] Table 4 Comparison of the test results of this method with the certificate values ​​and the analysis values ​​of other methods

[0064]

[0065] The errors between the determination result of sample 1 by this method and the certificate value, and the errors between the determination value of sample 2 by this method and the determination values ​​by titration method and ICP method all meet the requirements of the allowable error of sample analysis.

[0066] F) Conclusion: The sample was treated with nitric acid, and lithium tetraborate flux was added to melt the glass sample. The curve was analyzed by X-ray fluorescence spectrometer. The relative standard deviation RSD% (n=3) of manganese was 0.092, silicon was 2.34, phosphorus was 3.46, iron was 1.28, and the method precision was high. The measurement results were consistent with the certificate value and the chemical titration method ICP-AES method determination results, and the results were accurate and reliable.

[0067] The method is simple, rapid and feasible, and can meet the requirements for quantitative analysis of metallic manganese, silicon, phosphorus and iron in actual production.

[0068] Working principle: Use dilute nitric acid solution to dissolve, oxidize and evaporate the metal manganese sample. Use lithium tetraborate as flux and cobalt as the internal standard element of manganese. After high-temperature melting in a high-frequency melting furnace, the sample and lithium tetraborate are melted into a uniform, flat and smooth glass sample. The primary X-rays generated by the X-ray tube are irradiated to the surface of the glass sample. After the special X-rays are split by the crystal, the detector measures the X-ray fluorescence intensity at the 2θ angle corresponding to the selected characteristic wavelength. Based on the principle that the intensity of the characteristic spectral line of each element is proportional to the content, the mass fraction of each component such as manganese, silicon, phosphorus and iron in the sample is calculated according to the calibration curve and the measured X-ray fluorescence intensity.

[0069] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for detecting metallic manganese by X-ray fluorescence spectroscopy, characterized in that: The specific steps include: Step 1: pre-oxidize a series of standard samples of metallic manganese and melt them at high temperature to form a series of standard sample glass sheets; Step 2: Using an X-ray fluorescence spectrometer to measure the X-ray fluorescence intensity of the element to be measured in the series of standard sample glass sheets prepared in step 1, and draw a calibration curve of the element to be measured based on the X-ray fluorescence intensity of the element to be measured and the certificate value of the element in the standard sample; Step 3: pre-oxidizing the metal manganese sample and melting it at high temperature to make a sample glass sheet; Step 4: Use an X-ray fluorescence spectrometer to measure the X-ray fluorescence intensity of the element to be measured in the sample glass piece obtained in step 3, and calculate the mass fractions of manganese, silicon, phosphorus, iron and other components in the metallic manganese sample based on the calibration curve obtained in step 2.

2. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 1, characterized in that: The treatment process of step one and step three is the same, and the specific treatment process is: accurately weigh the sample and the internal standard into a platinum crucible, drip a wetting agent into the platinum crucible to wet the sample, and slowly and quantitatively drip an oxidant, after the violent reaction stops, evaporate the treated sample to dryness at low temperature, and then quantitatively cover the flux thereon, quantitatively drip a release agent, and melt the sample at high temperature in a melting furnace to form a uniform, flat, and smooth glass sheet.

3. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The component ratio of the sample, internal standard, wetting agent, oxidant, flux and release agent is 0.2g: 0.1g: 2ml: 6ml: 8g: 7d, and the sample is a standard metal manganese sample or a metal manganese sample to be tested.

4. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The internal standard is cobalt trioxide.

5. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The wetting agent is water.

6. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The oxidant is (1+1) dilute nitric acid.

7. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The flux is lithium tetraborate, and the release agent is potassium bromide.

8. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The temperature of the melting furnace when melting the sample is 1000 to 1100 degrees.

9. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The temperature of the treated sample when evaporated to dryness is 190 to 210 degrees.

10. The X-ray fluorescence spectrum detection method of metallic manganese according to claim 2, characterized in that: The production of the regression curve in step 2 is specifically as follows: select a series of gradient metal manganese standard samples, make standard sample glass slides according to the processing technology in step 1, then operate the standard glass slides through the X-ray fluorescence spectrometer, establish analysis tasks, analysis procedures, measure the X-ray fluorescence intensity, perform curve regression with the MVR function, and establish the working curves of each element.

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