A method for determining the carbon content in metallic manganese by infrared absorption

Abstract

The application provides an analysis method for determining the content of carbon element in metal manganese by an infrared absorption method. The analysis method comprises the following steps: firstly, sequentially performing acid washing, water washing and alcohol washing on a metal manganese sample, and drying to obtain a to-be-tested metal manganese; and then sequentially placing the obtained to-be-tested metal manganese, a tungsten-tin fluxing agent, a pure iron fluxing agent and a pure copper fluxing agent in a furnace for melting treatment, and testing the content of the carbon element in the metal manganese by the infrared absorption method. The analysis method provided by the application can realize stable detection of the low carbon content in the metal manganese sample, and improves the measurement accuracy.

Description

Technical Field

[0001] This invention belongs to the field of elemental analysis technology, specifically relating to an analytical method for determining the carbon content in metallic manganese by infrared absorption. Background Technology

[0002] Manganese is an important industrial metal with a variety of applications, mainly due to its combination of high strength, corrosion resistance, and magnetic properties. In modern industrial production, the performance and quality of metallic manganese directly affect the service life and safety of products. Therefore, the analysis of the composition of metallic manganese is particularly important, especially the detection of the content of elements such as carbon (C), silicon (Si), or sulfur (S).

[0003] Currently, the factors affecting the accuracy and precision of carbon content analysis results are quite complex. Improper handling at any stage of the testing process can cause serious deviations in the results. These factors include oxygen, crucible, flux, and sample preparation procedures. Oxygen can be purified by using high-purity oxygen (>99.999%) to reduce external contaminants, and the crucible can be pre-fired at high temperatures to reduce the introduction of impurities. Therefore, flux and sample preparation procedures are the main sources of impurities and require strict control to ensure the accuracy of the analytical results.

[0004] In carbon and sulfur analysis, the choice, amount, and order of flux addition all significantly affect the analytical results. For example, selecting a suitable flux is crucial to ensuring complete combustion of the sample and reducing the amount of molten oxide powder. The type of flux should be determined based on the furnace heating method, the melting point of the sample, and the requirements of the thermodynamic reaction. The amount and order of flux addition need to be precisely controlled to ensure complete combustion of the sample and reduce the introduction of impurities.

[0005] However, the detection range of fluxes disclosed in the prior art is 0.0010% to 0.2%, which usually has technical problems such as unstable detection results or excessively high detection limits for ultra-low carbon content analysis.

[0006] Therefore, there is an urgent need in this field to develop a method for analyzing ultra-low carbon content in order to solve the above problems. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide an analytical method for determining the carbon content in metallic manganese using infrared absorption spectroscopy. The analytical method provided by this invention enables stable detection of low carbon content in metallic manganese samples while improving measurement accuracy.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides an analytical method for determining the carbon content in metallic manganese by infrared absorption spectrometry, the analytical method comprising the following steps:

[0010] S1. The manganese metal sample was sequentially subjected to acid washing, water washing and alcohol washing, and then dried to obtain the manganese metal to be tested.

[0011] S2. The manganese metal, tungsten-tin flux, pure iron flux, and pure copper flux obtained in step S1 are placed in a furnace for melting treatment in sequence, and the carbon content in the manganese metal is tested by infrared absorption method.

[0012] On the one hand, by optimizing the pretreatment steps of manganese metal samples, this invention effectively reduces the interference of surface impurities on the test results, ultimately ensuring the accuracy and reliability of the test results. On the other hand, by controlling the type and placement order of the flux, this invention reduces the impact of premature volatilization of manganese metal on the test results, and ensures that the sample can be completely melted during the preparation process without splashing.

[0013] In summary, this invention significantly improves the quality and efficiency of sample preparation, reduces impurity interference, and enhances the accuracy and stability of low carbon content test results in metallic manganese by improving the preparation steps of metallic manganese samples, optimizing fluxes, and controlling the melting process.

[0014] In this invention, the infrared absorption method includes, for example, the high-frequency combustion-infrared absorption method. Specifically, in the presence of a flux, oxygen is introduced into a high-frequency induction furnace, which rapidly heats and melts the sample, releasing CO2 gas into the infrared absorption cell. The concentration of CO2 gas is measured by a carbon-sulfur analyzer, thereby obtaining the carbon content in metallic manganese.

[0015] Preferably, the acid washing process in step S1 includes treatment with a hydrochloric acid solution. This invention uses only a single hydrochloric acid solution to remove the oxide layer from the sample surface.

[0016] In this invention, the step of pickling includes mechanically processing the manganese metal sample to obtain a block sample with no oil stains on the surface.

[0017] Preferably, the hydrochloric acid solution comprises hydrochloric acid and water.

[0018] Preferably, the volume ratio of hydrochloric acid to water is 1:(4-6), for example, it can be 1:4, 1:4.2, 1:4.5, 1:4.8, 1:5, 1:5.2, 1:5.5, 1:5.8, 1:6, etc., but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0019] Preferably, the number of pickling operations in step S1 is no less than three times, for example, three, four, five, six, seven, eight or nine times, but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0020] Preferably, the pickling time in step S1 is 1 minute each time.

[0021] In this invention, the pickling can be performed under ultrasonic conditions.

[0022] Preferably, the number of water washings in step S1 is no less than three times, for example, three, four, five, six, seven, eight or nine times, but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0023] Preferably, the time for each water washing in step S1 is 20s to 1min, for example, 20s, 30s, 40s, 50s, 1min, etc., but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0024] Preferably, the alcohol washing time in step S1 is 1 min to 2 min, for example, it can be 1 min, 1.2 min, 1.5 min, 1.8 min, 2 min, etc., but it is not limited to the listed technical solutions. Other unlisted values ​​within the above range are also applicable.

[0025] In this invention, the alcohol washing reagents include, for example, anhydrous ethanol.

[0026] This invention improves the accuracy and stability of testing by controlling the pretreatment steps of manganese metal samples to fully remove impurities from their surface.

[0027] Preferably, the mass ratio of tungsten-tin flux, pure iron flux, and pure copper flux in step S2 is 1:0.7:0.5, but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0028] In this invention, by adjusting the mass ratio of tungsten-tin flux, pure iron flux, and pure copper flux, the sample melts better and produces less dust and powder, thereby reducing flux splashing.

[0029] Preferably, the total mass ratio of the tungsten-tin flux, pure iron flux, and pure copper flux to the mass ratio of the tested metal manganese in step S2 is 2.2:(0.06~0.07), for example, it can be 2.2:0.06, 2.2:0.061, 2.2:0.062, 2.2:0.063, 2.2:0.064, 2.2:0.065, 2.2:0.066, 2.2:0.067, 2.2:0.068, 2.2:0.069, 2.2:0.07, etc., but it is not limited to the listed technical solutions, and other unlisted values ​​within the above numerical ranges are also applicable.

[0030] In this invention, by adjusting the total mass ratio of tungsten-tin flux, pure iron flux, and pure copper flux to the mass ratio of the manganese metal to be tested, the manganese metal sample to be tested can be fully melted in a quartz crucible, allowing it to generate carbon dioxide in a sufficient oxygen environment, thereby enabling accurate detection of the carbon content in the manganese metal sample through the infrared cell in the instrument.

[0031] Preferably, the particle size of the tungsten-tin flux in step S2 is 0.6 mm to 0.9 mm, for example, it can be 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, etc., but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0032] Preferably, the particle size of the pure iron flux in step S2 is 2.2mm to 3.5mm, for example, it can be 2.2mm, 2.3mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, etc., but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0033] Preferably, the particle size of the pure copper flux in step S2 is 0.4 mm to 0.8 mm, for example, it can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, etc., but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0034] Preferably, the melting temperature in step S2 is 1200℃~1400℃, for example, it can be 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, etc.

[0035] Preferably, the melting treatment time in step S2 is 3h to 5h, for example, 3h, 3.5h, 4h, 4.5h, 5h, etc.

[0036] Preferably, the infrared absorption method described in step S2 is performed using an infrared carbon-sulfur analyzer to test the carbon content in metallic manganese.

[0037] Preferably, the operating conditions of the infrared carbon-sulfur analyzer are as follows: carrier flow rate of 2.5 L / min to 3.5 L / min, for example, 2.5 L / min, 2.6 L / min, 2.8 L / min, 3.0 L / min, 3.2 L / min, 3.5 L / min, etc.; carrier gas pressure of 30 psi to 35 psi, for example, 30 psi, 31 psi, 32 psi, 33 psi, 34 psi, 35 psi, etc.; and power gas pressure of 40 psi to 45 psi, for example, 40 psi, 41 psi, 42 psi, 43 psi, 44 psi, 45 psi, etc., but not limited to the listed technical solutions, other unlisted values ​​within the above ranges are also applicable.

[0038] This invention enables the sample to burn completely, the gas to be released completely, and the analysis results to be stable by adjusting the working conditions of the infrared carbon-sulfur analyzer, while also reducing the volatilization of dust.

[0039] Preferably, the analysis time of the infrared carbon-sulfur analyzer is 50s to 60s, for example, 50s, 52s, 55s, 58s, 60s, etc.; the comparison level is 1 to 3, but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0040] Preferably, the concentration of carbon in metallic manganese determined in the analytical method is ≥5ppm, for example, 5ppm, 6ppm, 7ppm, 8ppm, 9ppm, 10ppm, 12ppm, 15ppm, 18ppm, etc., but it is not limited to the listed technical solutions. Other unlisted values ​​within the above ranges are also applicable.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] This invention provides an analytical method for determining the carbon content in metallic manganese using infrared absorption spectroscopy. On one hand, by optimizing the pretreatment steps of the manganese sample, this invention effectively reduces the interference of surface impurities on the test results, ultimately ensuring the accuracy and reliability of the results. On the other hand, by controlling the type and placement order of the flux, this invention reduces the impact of premature volatilization of metallic manganese on the test results and ensures that the sample can be completely melted during preparation without splashing.

[0043] In summary, this invention significantly improves the quality and efficiency of sample preparation, reduces impurity interference, and enhances the accuracy and stability of low carbon content test results in metallic manganese by improving the preparation steps of metallic manganese samples, optimizing fluxes, and controlling the melting process. Attached Figure Description

[0044] Figure 1 This is a flowchart for determining the carbon content in metallic manganese using the infrared absorption method provided by the present invention. Detailed Implementation

[0045] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0046] In the embodiments and comparative examples of this invention, the purity of the tungsten-tin flux, the pure iron flux, and the pure copper flux are all above 99.99%, and the purity of the oxygen atmosphere is above 99.999%.

[0047] Example 1

[0048] This embodiment provides an analytical method for determining the carbon content in metallic manganese using infrared absorption spectroscopy. The analytical method includes the following steps:

[0049] S1. The manganese metal sample and hydrochloric acid solution were acid-washed three times, with each acid-washing time being 1 min and the volume ratio of hydrochloric acid to water being 1:5. After the acid-washing was completed, the sample was rinsed three times with pure water (each water rinse time being 40 s) and then washed with anhydrous ethanol for 1.5 min. The sample was then dried under an infrared lamp for 3 min to obtain the manganese metal to be tested.

[0050] S2. 0.065g of the manganese metal to be tested, 1g of tungsten-tin flux, 0.7g of pure iron flux, and 0.5g of pure copper flux obtained in step S1 were placed in a crucible and melted at 1200℃ in an oxygen atmosphere for 4 hours. The particle size of the tungsten-tin flux was 0.8mm, the particle size of the pure iron flux was 3mm, and the particle size of the pure copper flux was 0.6mm. The released gas was collected and analyzed using an infrared carbon-sulfur analyzer by infrared absorption method. The carbon content in the manganese metal was determined, and the results are shown in Table 1. The operating conditions of the infrared carbon-sulfur analyzer were: carrier flow rate 3.1L / min, carrier gas pressure 35psi, and power gas pressure 43psi; the analysis time of the infrared carbon-sulfur analyzer was 60s, and the comparison level was 1-3.

[0051] Example 2

[0052] This embodiment provides an analytical method for determining the carbon content in metallic manganese using infrared absorption spectroscopy. The analytical method includes the following steps:

[0053] S1. The manganese metal sample and hydrochloric acid solution were acid-washed three times, with each acid-washing time being 1 min and the volume ratio of hydrochloric acid to water being 1:4. After the acid-washing was completed, the sample was rinsed three times with pure water (each water rinse time being 20 s) and then washed with anhydrous ethanol for 1 min. The sample was then dried under an infrared lamp for 3 min to obtain the manganese metal sample to be tested.

[0054] S2. 0.06g of the manganese metal to be tested, 1g of tungsten-tin flux, 0.7g of pure iron flux, and 0.5g of pure copper flux obtained in step S1 were placed in a crucible and melted at 1200℃ in an oxygen atmosphere for 4 hours. The particle size of the tungsten-tin flux was 0.6mm, the particle size of the pure iron flux was 2.2mm, and the particle size of the pure copper flux was 0.4mm. The released gas was collected and analyzed using an infrared carbon-sulfur analyzer by infrared absorption method. The carbon content in the manganese metal was determined, and the results are shown in Table 1. The operating conditions of the infrared carbon-sulfur analyzer were: carrier flow rate 2.8L / min, carrier gas pressure 32psi, and power gas pressure 42psi; the analysis time of the infrared carbon-sulfur analyzer was 57s, and the comparison level was 1-3.

[0055] Example 3

[0056] This embodiment provides an analytical method for determining the carbon content in metallic manganese using infrared absorption spectroscopy. The analytical method includes the following steps:

[0057] S1. The manganese metal sample and hydrochloric acid solution were acid-washed three times, with each acid-washing time being 1 min and the volume ratio of hydrochloric acid to water being 1:6. After the acid-washing was completed, the sample was rinsed three times with pure water (each water rinse time being 1 min) and then rinsed with anhydrous ethanol for 2 min. The sample was then dried under an infrared lamp for 3 min to obtain the manganese metal to be tested.

[0058] S2. Sequentially place 0.07g of the manganese metal to be tested, 1g of tungsten-tin flux, 0.7g of pure iron flux, and 0.5g of pure copper flux obtained in step S1 into a crucible and melt them at 1200℃ in an oxygen atmosphere for 4 hours. The particle size of the tungsten-tin flux is 0.9mm, the particle size of the pure iron flux is 3.5mm, and the particle size of the pure copper flux is 0.8mm. Collect the released gas and analyze it using an infrared carbon-sulfur analyzer using infrared absorption method to determine the carbon content in the manganese metal. The results are shown in Table 1. The operating conditions of the infrared carbon-sulfur analyzer are: carrier flow rate 3.5L / min, carrier gas pressure 35psi, and power gas pressure 45psi; the analysis time of the infrared carbon-sulfur analyzer is 50s, and the comparison level is 1-3.

[0059] Example 4

[0060] The difference between this embodiment and embodiment 1 is that the mass ratio of tungsten-tin flux, pure iron flux, and pure copper flux in step S2 is 1:0.3:0.2, while all other aspects are the same as in embodiment 1.

[0061] Example 5

[0062] The difference between this embodiment and Embodiment 1 is that the mass ratio of tungsten-tin flux, pure iron flux, and pure copper flux in step S2 is 0.5:2:1, while all other aspects are the same as in Embodiment 1.

[0063] Example 6

[0064] The difference between this embodiment and Embodiment 1 is that the mass of the manganese metal to be tested in step S2 is 0.03g, while all other aspects are the same as in Embodiment 1.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is that in step S1, the hydrochloric acid solution is replaced with an equal amount of nitric acid solution; otherwise, they are the same as in Example 1.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that, except for the absence of pure copper in the flux in step S2 (the mass ratio of tungsten-tin to pure iron and the total mass added are the same as in Example 1), everything else is the same as in Example 1.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 1 is that, except for the absence of pure iron in the flux in step S2 (the mass ratio of tungsten-tin to pure copper and the total mass added are the same as in Example 1), everything else is the same as in Example 1.

[0071] Comparative Example 4

[0072] The difference between this comparative example and Example 1 is that the material placement order in step S2 is as follows: pure iron flux, pure copper flux, and the metallic manganese and tungsten-tin flux obtained in step S1. All other aspects are the same as in Example 1.

[0073] Comparative Example 5

[0074] The difference between this comparative example and Example 1 is that the material placement order in step S2 is as follows: tungsten-tin flux, metallic manganese obtained in step S1, pure iron flux, and pure copper flux. All other aspects are the same as in Example 1.

[0075] The carbon content in metallic manganese provided in the above embodiments and comparative examples was determined according to the conditions of high-frequency induction furnace combustion infrared absorption method (standard state: current). Figure 1As shown, after the above embodiments and comparative examples were melted and the released gas was treated with anhydrous magnesium chloride to remove moisture, the sulfur content in the gas was tested using an infrared carbon-sulfur analyzer. Sulfur dioxide in the gas was converted to sulfur trioxide, and the sulfur trioxide was absorbed using degreased cotton to remove sulfur-containing substances from the gas. The carbon content in the gas was then tested using an infrared carbon-sulfur analyzer. The test results are shown in Table 1.

[0076] Table 1

[0077] Carbon content (ppm) Example 1 7.24 Example 2 8.13 Example 3 8.25 Example 4 6.67 Example 5 6.10 Example 6 6.92 Comparative Example 1 7.03 Comparative Example 2 5.71 Comparative Example 3 5.14 Comparative Example 4 6.48 Comparative Example 5 6.79

[0078] As can be seen from Table 1, this invention achieves stable and efficient detection of carbon in metallic manganese by improving the preparation steps of metallic manganese samples and further controlling the type of flux, the order of material addition and their ratio. In particular, it has good detection accuracy and stability for the detection of carbon content in metallic manganese with a carbon content ≥ 5 ppm.

[0079] Comparing Example 1 with Example 4 and Example 5, it can be seen that the present invention, by optimizing the flux ratio, enables the sample to melt better and produces less dust and powder, thereby reducing flux splashing.

[0080] Comparing Example 1 and Example 6, it can be seen that the present invention, by adjusting the ratio of the total mass of the manganese metal sample to be tested to the total mass of the flux, enables the manganese metal sample to be tested to be fully melted in the quartz crucible, so that it can generate carbon dioxide in a sufficient oxygen environment, thereby accurately detecting the carbon content in the manganese metal sample to be tested through the infrared cell in the instrument.

[0081] Comparing Example 1 with Comparative Example 1, it can be seen that changing the type of acid solution can improve the accuracy of carbon content determination.

[0082] Comparing Example 1 with Comparative Examples 2 and 3, it can be seen that the present invention, by optimizing the type and ratio of flux, enables the manganese sample to be tested to be completely melted during the detection process, releasing the carbon element in the sample to react with oxygen.

[0083] Comparing Example 1 with Comparative Examples 4 and 5, it can be seen that the present invention, by adjusting the placement order between the sample and various fluxes, ensures that the tested manganese sample can be completely burned, and the detection baseline has no tailing peaks, the peak shape is complete, and the detection results are more accurate.

[0084] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An analytical method for determining the carbon content in metallic manganese by infrared absorption, characterized in that, The analytical method includes the following steps: S1. The manganese metal sample is subjected to acid washing, water washing and alcohol washing in sequence, and then dried to obtain the manganese metal to be tested; the acid washing process is carried out by treating with hydrochloric acid solution; the hydrochloric acid solution includes hydrochloric acid and water, and the volume ratio of hydrochloric acid to water is 1:(4~6); S2. The manganese metal, tungsten-tin flux, pure iron flux, and pure copper flux obtained in step S1 are placed in a furnace for melting treatment in sequence, and the carbon content in the manganese metal is tested by infrared absorption method; the mass ratio of the tungsten-tin flux, pure iron flux, and pure copper flux is 1:0.7:0.

5.

2. The analytical method according to claim 1, characterized in that, The number of pickling operations in step S1 shall be no less than three.

3. The analytical method according to claim 2, characterized in that, The pickling time in step S1 is 1 minute each time.

4. The analytical method according to claim 1, characterized in that, The number of water washes in step S1 shall be no less than three.

5. The analytical method according to claim 4, characterized in that, The time for each water wash in step S1 is 20 seconds to 1 minute.

6. The analytical method according to claim 1, characterized in that, The alcohol washing time in step S1 is 1 min to 2 min.

7. The analytical method according to claim 1, characterized in that, In step S2, the total mass ratio of the tungsten-tin flux, pure iron flux, and pure copper flux to the mass ratio of the manganese metal to be tested is 2.2:(0.06-0.07).

8. The analytical method according to claim 1, characterized in that, The particle size of the tungsten-tin flux mentioned in step S2 is 0.6 mm to 0.9 mm.

9. The analytical method according to claim 1, characterized in that, The particle size of the pure iron flux mentioned in step S2 is 2.2 mm to 3.5 mm.

10. The analytical method according to claim 1, characterized in that, The particle size of the pure copper flux mentioned in step S2 is 0.4 mm to 0.8 mm.

11. The analytical method according to claim 1, characterized in that, The melting temperature in step S2 is 1200℃~1400℃.

12. The analytical method according to claim 1, characterized in that, The melting treatment time in step S2 is 3h to 5h.

13. The analytical method according to claim 1, characterized in that, The infrared absorption method described in step S2 uses an infrared carbon-sulfur analyzer to analyze and test the carbon content in metallic manganese.

14. The analytical method according to claim 13, characterized in that, The operating conditions of the infrared carbon-sulfur analyzer are as follows: carrier flow rate 2.5 L / min to 3.5 L / min, carrier gas pressure 30 psi to 35 psi, and power gas pressure 40 psi to 45 psi.

15. The analytical method according to claim 13, characterized in that, The infrared carbon-sulfur analyzer has an analysis time of 50s to 60s and a comparison level of 1 to 3.

16. The analytical method according to claim 1, characterized in that, The analytical method specifies that the concentration of carbon in metallic manganese is ≥5 ppm.

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