Method for detecting trace sulfur in metal material based on combination of double combustion furnaces and ultraviolet fluorescence

Abstract

The invention discloses a method for detecting trace sulfur in a metal material based on double combustion furnace-ultraviolet fluorescence combination, which comprises the following steps: S1, pretreating a crucible, and placing the pretreated crucible in a double combustion furnace-ultraviolet fluorescence analyzer for later use; s2, pretreating a sample to be analyzed; s3, debugging the double combustion furnace-ultraviolet fluorescence analyzer, and setting analysis conditions; s4, establishment of a standard working curve: selecting the analysis conditions in the step S3, performing standardized correction by taking a standard sample containing sulfur in a metal material as a low-sulfur standard sample, and establishing the standard working curve; and S5, determining the pretreated to-be-analyzed sample according to the analysis conditions in the step S3, and calculating the content of sulfur in the to-be-analyzed sample according to the standard working curve in the step S4. According to the method, the double-combustion furnace-ultraviolet fluorescence analyzer is used as a measuring instrument, the analysis steps are simple and convenient, the analysis speed is high, the result accuracy is high, and the detection problem of rapidly determining the ultra-trace sulfur in the metal material is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of elemental analysis, and particularly relates to a method for detecting trace sulfur in metal materials based on the combination of dual combustion furnaces and ultraviolet fluorescence. Background Art

[0002] Metal materials have good strength, fracture properties, and tissue stability, and also have excellent oxidation resistance, corrosion resistance, fatigue resistance, creep resistance, etc. They are key materials that are irreplaceable in modern national defense construction and the development of the national economy. The purity of metal materials has a very important impact on their properties. For example, the presence of impurities or trace elements may form defects or second-phase particles in the metal matrix, which may all become crack sources and lead to early failure under stress; impurity elements such as carbon, sulfur, and oxygen can react with the metal matrix to form a local battery effect, promoting the electrochemical corrosion process and resulting in a decrease in the corrosion resistance of metal materials. Therefore, mastering the content of impurity elements in metal materials has an important impact on the control of alloy properties and the smelting of alloys.

[0003] Impurity elements that may be contained in metal materials include carbon, sulfur, oxygen, nitrogen, etc. Among them, sulfur element, as one of the typical impurity elements in metal materials, its presence will have a series of adverse effects on metal materials. For example, sulfur element will form a low-melting eutectic with metal materials, resulting in hot brittleness of metal materials; when the sulfur content in metal elements is relatively high, cracks may occur during the welding process; sulfur element will affect the toughness and ductility of metal materials. Based on the influence of sulfur element on the properties of metal materials, it is necessary to detect the sulfur element in metal materials with high precision to understand the influence law of sulfur element on the formation of harmful tissues and casting defects during the alloy solidification process, determine the control limits of the main elements and impurity element types in the alloy, master the law of sulfur removal during the metallurgical process of alloy materials, clarify the mechanism of efficient desulfurization and fine control of composition of alloys, and have a profound impact on the establishment of ultra-pure smelting technology for laboratory alloys.

[0004] At present, whether it is international standards, national standards, or industry standards, the detection of sulfur elements in metal materials generally uses the infrared absorption method, but the lowest detection limit of its sulfur content is 5 μg / g (0.0005%). For example, in the national recommended standard "GB / T 20123-2006 Determination of total carbon and sulfur content in steel - Infrared absorption method after combustion in high-frequency induction furnace (conventional method)", the total carbon and sulfur content in steel materials is determined by the infrared absorption method after combustion in a high-frequency induction furnace, and the applicable range of sulfur is 0.0005% - 0.33%. With the development of high-end fields such as aerospace, nuclear industry, and electronics industry, higher requirements are put forward for the purity of metal materials, and the above detection limit of sulfur elements can no longer meet the requirements of high-end fields for the purity of metal materials. Therefore, how to optimize and improve the lower limit of determination of instrument detection and detect ultra-trace sulfur in metal materials with high precision is an urgent problem to be solved at present. Summary of the Invention

[0005] The object of the present invention is to provide a method for detecting trace sulfur in metal materials based on the combination of double combustion furnaces - ultraviolet fluorescence, so as to solve the problem of high detection limit in detecting the sulfur content in metal materials by using an infrared detector.

[0006] To achieve the above object, the present invention provides a method for detecting trace sulfur in metal materials based on the combination of double combustion furnaces - ultraviolet fluorescence, including the following steps:

[0007] S1: Pretreat the crucible, and then place the crucible in a double combustion furnace - ultraviolet fluorescence analyzer for later use;

[0008] S2: Pretreat the sample to be analyzed;

[0009] S3: Debug the double combustion furnace - ultraviolet fluorescence analyzer and set the analysis conditions;

[0010] S4: Establishment of the standard working curve: Select the analysis conditions in step S3, and use a standard sample containing sulfur in the metal material as a low-sulfur standard sample for standardization correction to establish the standard working curve;

[0011] S5: According to the analysis conditions in step S3, measure the pretreated sample to be analyzed, and calculate the sulfur content in the sample to be analyzed according to the standard working curve in step S4.

[0012] Preferably, in step S1, the specific process of crucible pretreatment is as follows:

[0013] S11: Put the ceramic crucible into a muffle furnace and burn it at 1100 °C for 2 hours;

[0014] S12: Take out the ceramic crucible, wait for it to cool, and place it in a desiccator. At the same time, put silica gel in the desiccator to adsorb the moisture in the ceramic crucible.

[0015] Preferably, in step S2, the sample to be analyzed is a block sample, a chip sample or a powder sample; when the sample to be analyzed is a block sample or a chip sample, the sample to be analyzed is cleaned with an organic solvent and air-dried for later use; when the sample to be analyzed is a powder sample, it is used directly.

[0016] Preferably, in step S2, the organic solvent is one or more of methanol, ethanol, acetone, ether, chloroform, and tetrachloromethane.

[0017] Preferably, in step S2, the block sample is cleaned with an organic solvent to remove the surface oxide layer, and then made into chips or small particles, the weight of a single chip or small particle does not exceed 1.00g, and then cleaned with analytical grade acetone or anhydrous ethanol, dried with cold air or naturally dried, to obtain the pretreated sample to be analyzed.

[0018] Preferably, in step S3, the debugging process is: selecting the combustion furnace type as a high-frequency combustion furnace and a tubular furnace; adjusting the instrument low-sulfur baseline so that its signal fluctuation is as close to 0 as possible; adjusting the low-sulfur peak signal to ensure that its signal is a Gaussian curve as much as possible; the analysis conditions are: adjusting the sample analysis power, adjusting the sample sampling time, selecting an appropriate flux, automatically injecting a carrier gas blank before each detection, and calibrating the baseline signal in real time.

[0019] Preferably, in step S3, the temperature of the high-frequency combustion furnace is 1300-2500° C., the analysis power is 1800-2200 W, and the sample sampling time is 30-180 s.

[0020] Preferably, in step S4, the low sulfur standards are IARM 188A, YSBC 41502-215, YSBC 11024a-2011 and YSBC 41350-2015, the sulfur content in IARM 188A is 0.00018%, the sulfur content in YSBC 41502-215 is 0.0006%, the sulfur content in YSBC 11024a-2011 is 0.0015%, and the sulfur content in YSBC 41350-2015 is 0.0044%.

[0021] Preferably, in step S5, the specific process of measuring the sample to be analyzed is:

[0022] A1. Analyze the blank value a of sulfur in tungsten flux: weigh a certain amount of tungsten flux and place it in a ceramic crucible. Enter the corresponding mass of tungsten flux into the double combustion furnace-ultraviolet fluorescence analyzer. After oxygen combustion, measure and analyze the combustion products to obtain the blank value a of sulfur in tungsten flux.

[0023] A2. Analyze the sulfur content value b in the sample to be analyzed: Weigh a quantitative sample to be analyzed and mix it with tungsten flux, then place the mixture in a ceramic crucible. Input the mass of the sample to be analyzed and the mass of the tungsten flux into a dual combustion furnace-ultraviolet fluorescence analyzer respectively. After oxygen combustion, measure and analyze the combustion products. After deducting the blank value a of the tungsten flux, obtain the sulfur content value b in the sample to be analyzed.

[0024] Preferably, step A1 is repeated at least three times, and the average value is taken from the blank values a of sulfur in the tungsten flux obtained multiple times for use; step A2 is repeated at least three times, and the average value is taken from the sulfur content values b in the samples to be analyzed obtained multiple times for use.

[0025] Preferably, in step S5, the detection range of sulfur content is 0.00001 - 0.01%, and the determination lower limit is 0.00001%.

[0026] Therefore, the method for detecting trace sulfur in metal materials based on the combination of dual combustion furnace-ultraviolet fluorescence used in the present invention has the following beneficial effects:

[0027] (1) The present invention uses a dual combustion furnace-ultraviolet fluorescence analyzer to detect sulfur elements in metal materials. With an integrated combustion-detection design, by shortening the distance between the combustion chamber and the reaction chamber and purifying and transporting the sample gas, the residence time of sulfur dioxide is controlled within seconds, reducing oxidation loss and improving detection accuracy.

[0028] (2) The present invention adopts a dynamic baseline correction technology. Before each detection, a carrier gas blank is automatically injected to calibrate the baseline signal in real time, ensuring the detection accuracy of trace sulfur elements.

[0029] Next, through examples, the technical solutions of the present invention will be further described in detail. Specific Embodiments

[0030] The following will further describe the present invention. It should be noted that this embodiment is based on the present technical solution, and detailed implementation methods and specific operation processes are given, but the present invention is not limited to this embodiment.

[0031] Example 1

[0032] The method for detecting trace sulfur in metal materials based on the combination of dual combustion furnace-ultraviolet fluorescence includes the following steps:

[0033] S1: Pretreat the crucible, and then place the crucible in a dual combustion furnace-ultraviolet fluorescence analyzer for standby;

[0034] The specific process of crucible pretreatment is as follows:

[0035] S11: Put the ceramic crucible into a muffle furnace and burn it at 1100°C for 2 hours;

[0036] S12: Take out the ceramic crucible, and place it in a desiccator after cooling. Meanwhile, color-changing silica gel is placed in the desiccator to absorb moisture in the ceramic crucible.

[0037] Pre-treating the crucible can dehumidify the surface of the crucible and prevent the remaining moisture on the crucible from causing slight errors during subsequent use, resulting in inaccurate measurement data.

[0038] S2: pre-processing the samples to be analyzed;

[0039] The sample to be analyzed is a block sample. The block sample is cleaned with ethanol to remove the surface oxide layer, and then made into small particles. The weight of a single small particle does not exceed 1.00g. It is then cleaned with analytical pure acetone and naturally air-dried to obtain the pretreated sample to be analyzed.

[0040] S3: Debug the dual combustion furnace-ultraviolet fluorescence analyzer and set the analysis conditions;

[0041] The debugging process is as follows: select the combustion furnace type as a high-frequency combustion furnace and a tubular furnace (temperature is 2000℃); adjust the instrument's low-sulfur baseline so that its signal fluctuation is as close to 0 as possible; adjust the low-sulfur peak signal to ensure that its signal is a Gaussian curve as much as possible; the analysis conditions are as follows: adjust the sample analysis power to 2000W, adjust the sample sampling time to 100s, select an appropriate flux, automatically inject a carrier gas blank before each test, and calibrate the baseline signal in real time.

[0042] S4: Establishment of standard working curve: Select the analysis conditions in step S3, use the standard sample containing sulfur in the metal material as the low-sulfur standard sample for standardization calibration, and establish the standard working curve with the peak area of ​​the release curve as the horizontal axis and the absolute amount of the sample as the vertical axis; the standard curve is shown in Table 1.

[0043] Table 1 Standard curve

[0044]

[0045] S5: According to the analysis conditions in step S3, the pretreated sample to be analyzed is measured, and the sulfur content in the sample to be analyzed is calculated according to the standard working curve in step S4;

[0046] The specific process of measuring the sample to be analyzed is as follows:

[0047] A1. Analyze the blank value a of sulfur in tungsten flux: Weigh 1.50g of tungsten flux and place it in a ceramic crucible. Input the corresponding mass of tungsten flux into the double combustion furnace-ultraviolet fluorescence analyzer. After oxygen combustion, measure and analyze the combustion products to obtain the blank value a of sulfur in tungsten flux.

[0048] A2. Analyze the sulfur content value b in the sample to be analyzed: Weigh 0.50 g of the sample to be analyzed and mix it with 1.50 g of tungsten flux, then place them in a ceramic crucible. Input the mass of the sample to be analyzed and the mass of the tungsten flux into the double combustion furnace-ultraviolet fluorescence analyzer respectively. After oxygen combustion, measure and analyze the combustion products. After deducting the blank value a of the tungsten flux, obtain the sulfur content value b in the sample to be analyzed.

[0049] Step A1 is repeated at least three times, and the average value is taken from the blank values a of sulfur in the tungsten flux obtained multiple times for use; Step A2 is repeated at least three times, and the average value is taken from the sulfur content values b in the sample to be analyzed obtained multiple times for use.

[0050] After being detected by the above method, the sulfur content in the sample to be analyzed is 0.00005%.

[0051] The present invention uses a double combustion furnace-ultraviolet fluorescence analyzer as the measuring instrument, a ceramic crucible as the container, conducts detection through the ultraviolet fluorescence instrument, and uses a metal standard sample with a certain standard value as the sulfur standard sample for standardization and calibration, solving the problem of rapid determination of ultra-trace sulfur content in metal materials. The method of the present invention has simple analysis steps, fast analysis speed, and high result accuracy, providing a reliable technical guarantee for the smelting, application, and quality control of metal materials, and effectively cooperating with the progress of scientific research special production work.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for detecting trace sulfur in metal materials by combining a dual combustion furnace and ultraviolet fluorescence, characterized in that, The following steps are involved: S1: pre-treat the crucible, and then place the crucible in a double combustion furnace-ultraviolet fluorescence analyzer for standby use; S2: pre-processing the samples to be analyzed; S3: Debug the dual combustion furnace-ultraviolet fluorescence analyzer and set the analysis conditions; S4: Establishment of a standard working curve: Select the analysis conditions in step S3, use a standard sample containing sulfur in a metal material as a low-sulfur standard sample for standardization calibration, and establish a standard working curve; S5: According to the analysis conditions in step S3, the pretreated sample to be analyzed is measured, and the sulfur content in the sample to be analyzed is calculated according to the standard working curve in step S4.

2. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 1, wherein In step S1, the specific process of crucible pretreatment is: S11: placing the ceramic crucible in a muffle furnace and calcining at 1100°C for 2 hours; S12: Take out the ceramic crucible, and place it in a desiccator after cooling. Meanwhile, color-changing silica gel is placed in the desiccator to absorb moisture in the ceramic crucible.

3. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 1, characterized in that In step S2, the sample to be analyzed is a block sample, a chip sample or a powder sample; when the sample to be analyzed is a block sample or a chip sample, the sample to be analyzed is washed with an organic solvent and air-dried for later use; when the sample to be analyzed is a powder sample, it is used directly.

4. The method for detecting trace sulfur in metal materials based on the combination of dual combustion furnace and ultraviolet fluorescence according to claim 3, wherein, In step S2, the organic solvent is one or more of methanol, ethanol, acetone, ether, chloroform, and tetrachloromethane.

5. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 4, wherein In step S2, the block sample is cleaned with an organic solvent to remove the surface oxide layer, and then made into chips or small particles, the weight of a single chip or small particle does not exceed 1.00g, and then cleaned with analytical pure acetone or anhydrous ethanol, dried with cold air or naturally dried, to obtain the pre-treated sample to be analyzed.

6. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 1, characterized in that, In step S3, the debugging process is: select the combustion furnace type as a high-frequency combustion furnace and a tubular furnace; adjust the instrument low-sulfur baseline so that its signal fluctuation is as close to 0 as possible; adjust the low-sulfur peak signal to ensure that its signal is a Gaussian curve as much as possible; the analysis conditions are: adjust the sample analysis power, adjust the sample sampling time, select an appropriate flux, automatically inject a carrier gas blank before each detection, and calibrate the baseline signal in real time.

7. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 1, characterized in that In step S4, the low sulfur standards are IARM 188A, YSBC 41502-215, YSBC 11024a-2011 and YSBC41350-2015, the sulfur content in IARM 188A is 0.00018%, the sulfur content in YSBC 41502-215 is 0.0006%, the sulfur content in YSBC 11024a-2011 is 0.0015%, and the sulfur content in YSBC 41350-2015 is 0.0044%.

8. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 1, characterized in that In step S5, the specific process of measuring the sample to be analyzed is: A1. Analyze the blank value a of sulfur in tungsten flux: weigh a certain amount of tungsten flux and place it in a ceramic crucible. Enter the corresponding mass of tungsten flux into the double combustion furnace-ultraviolet fluorescence analyzer. After oxygen combustion, measure and analyze the combustion products to obtain the blank value a of sulfur in tungsten flux. A2. Analyze the sulfur content value b in the sample to be analyzed: Weigh a quantitative sample to be analyzed and mix it with tungsten flux, then place them in a ceramic crucible. Input the mass of the sample to be analyzed and the mass of tungsten flux into a double combustion furnace - ultraviolet fluorescence analyzer respectively. After combustion in oxygen, conduct determination and analysis on the combustion products. After deducting the blank value a of tungsten flux, obtain the sulfur content value b in the sample to be analyzed.

9. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 8, wherein Step A1 is repeated at least three times, and the average value is taken from the blank values a of sulfur in tungsten flux obtained multiple times for use; Step A2 is repeated at least three times, and the average value is taken from the sulfur content values b in the sample to be analyzed obtained multiple times for use.

10. The method for detecting trace sulfur in metal materials based on the combination of double combustion furnace and ultraviolet fluorescence according to claim 9, characterized in that, In Step S5, the detection range of sulfur content is 0.00001~0.01%, and the determination lower limit is 0.00001%.

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