Method for detecting content of each element in slag

Abstract

The invention discloses a method for detecting the content of each element in slag. The method comprises the following steps: 1) pre-melting a sample; 2) manufacturing a glass sheet; (3) carrying out spectrum detection on the glass sheet prepared in the step (2) by utilizing a fluorescence spectrophotometer; wherein in the step 1), a mixed flux of lithium tetraborate and lithium metaborate and sodium nitrate are used for pre-melting treatment of a sample, and a sample melt is obtained; in the step (2), a mixed flux of lithium tetraborate and lithium metaborate is used for conducting melting treatment on the sample melt again, and the glass sheet is obtained.By means of the method, determination of CaO, SiO2, MgO, Al2O3, MnO, TiO2 and P2O5 in the furnace slag can be completed at the same time.

Description

Technical Field

[0001] This invention belongs to the field of mineral raw material analysis technology, specifically relating to a method for detecting the content of various elements in slag, and particularly to a method for detecting the content of CaO, SiO2, MgO, Al2O3, MnO, TiO2, and P2O5 in blast furnace slag, converter slag, and other slags. Background Technology

[0002] Slag is an important byproduct of iron and steel smelting and refining processes. Its main components include oxides such as CaO, FeO, MnO, and MgO, along with small amounts of sulfides. Currently, the main analytical methods for slag include chemical methods, atomic absorption spectrometry, and inductively coupled plasma-atomic emission spectrometry (ICP-AES). However, due to the complex matrix composition of slag and the large number of elements requiring analysis, these methods share the drawbacks of relatively cumbersome sample preparation, slow speed, and high cost. With the development and application of X-ray fluorescence spectrometry, there are reports of using the pellet method to determine the main and secondary components in slag, but most of these methods have a narrow applicability, only suitable for single slag varieties with stable matrices and small fluctuations in element content. Summary of the Invention

[0003] This invention aims to solve the problem of the inability to simultaneously and rapidly detect the content of various elements in slag, and the corrosion of platinum crucibles during conventional melting and glass sheet preparation. The detection method of this invention has been applied in production practice and has been verified as a fast, accurate, efficient, and environmentally friendly method.

[0004] The present invention is specifically implemented through the following technical solutions.

[0005] This invention provides a method for detecting the content of various elements in slag, which includes the following steps:

[0006] 1) Sample pre-melting;

[0007] 2) Making glass slides;

[0008] 3) Perform spectral analysis on the glass slide obtained in step 2) using a fluorescence spectrometer;

[0009] in:

[0010] In step 1), the sample is pre-melted using a mixed flux of lithium tetraborate and lithium metaborate and sodium nitrate to obtain a sample melt.

[0011] In step 2), the sample melt is melted again using a mixed flux of lithium tetraborate and lithium metaborate to obtain the glass sheet;

[0012] The elements in the slag include: CaO, SiO2, MgO, Al2O3, MnO, TiO2 and P2O5.

[0013] In some embodiments, in step 1), the pre-melting process is carried out in an alumina crucible with graphite powder as the reaction substrate.

[0014] In some embodiments, the pre-melting treatment conditions are: melting at 1000°C for 30 minutes.

[0015] In some embodiments, the ratio of lithium tetraborate to lithium metaborate in the mixed flux is 2:1.

[0016] In some embodiments, step 1) is performed as follows: 0.4000 g of the sample, (3.0 ± 0.0002) g of lithium tetraborate and lithium metaborate mixed flux, and (0.25 ± 0.0002) g of sodium nitrate are mixed and placed in a 30 mL corundum crucible lined with graphite powder. The mixture is then melted in a high-temperature furnace at 1000 °C for 30 min, removed, and cooled to obtain the sample melt.

[0017] In some embodiments, step 2) is performed as follows: (4.0 ± 0.0002) g of lithium tetraborate and lithium metaborate mixed flux are weighed and spread evenly in a platinum crucible. The pre-melted sample melt is placed into the platinum crucible, and 10 to 15 drops of lithium bromide release agent are added evenly. The crucible is then placed in a high-frequency furnace with a pre-programmed setting for melting. After cooling, the glass sheet is obtained.

[0018] In some embodiments, step 3) is performed by using the side of the glass slide that is close to the bottom of the crucible as the irradiation surface and performing spectral detection using the fluorescence spectrometer.

[0019] The present invention has the following beneficial effects:

[0020] Slag is a crucial byproduct of iron and steel smelting and refining. Controlling the composition and properties of slag during smelting can remove harmful impurities from the metal, enrich metal oxides, ensure smooth smelting operations, and control product quality. Common analytical methods for slag include chemical methods, atomic absorption spectrometry, and inductively coupled plasma atomic emission spectrometry (ICP-AES). However, these methods suffer from complex matrix composition, require the analysis of numerous elements, and suffer from drawbacks such as cumbersome sample preparation, slow processing speed, and high cost. This method utilizes X-ray fluorescence spectrometry to achieve simultaneous, rapid, accurate, and efficient determination of multiple elements. Detailed Implementation

[0021] This invention discloses a method for determining the content of various elements in slag using X-ray fluorescence spectrometry. Specifically, it comprises the following steps:

[0022] The sample is pre-oxidized and melted in a corundum crucible containing graphite. After oxidation, the sample is completely converted into oxides and then melted at high temperature in a platinum crucible to form a glass slide. The slide is then irradiated with primary X-rays to generate a fluorescence spectrum of the element to be analyzed. The spectrum is then dispersed by a diffraction crystal to measure the intensity. Based on the calibration curve prepared from the standard sample, the content of the analytical element in the sample is determined.

[0023] The present invention will be described in detail below through specific embodiments. These embodiments are intended to help understand the present invention and are not intended to limit the scope of the present invention.

[0024] 1. Reagents and Materials

[0025] 1. Unless otherwise stated, only approved analytical reagents of superior purity are used in the analysis.

[0026] 2. Graphite powder, solid.

[0027] 3. Sodium nitrate, solid.

[0028] 4. Lithium tetraborate and lithium metaborate mixed flux, 66.67%:33.33%, GR.

[0029] 5. Lithium bromide release agent, saturated lithium bromide solution.

[0030] 6. Porcelain Ark, 20 mL.

[0031] 7. Corundum crucible sleeve, 30 mL.

[0032] 8. Platinum gold crucible.

[0033] 9. Instruments

[0034] 1. X-ray fluorescence spectrometer (recommended values ​​for the determination parameters of each element are shown in Table 1 below)

[0035] 2. High-frequency melting furnace

[0036] Table 1: Recommended Measurement Parameters

[0037]

[0038] 2 Experimental Methods

[0039] 2.1 Blank Test

[0040] Perform blank tests along with the sample.

[0041] 2.2 Determination of sample premelting

[0042] The weighed sample, (3.0±0.0002) g of lithium tetraborate and lithium metaborate mixed flux, and (0.25±0.0002) g of sodium nitrate were mixed and placed in a 30 mL corundum crucible lined with graphite powder. The mixture was then melted in a high-temperature furnace at 1000℃ for 30 min, removed, and cooled. The molten sample was then removed, and the graphite powder on the surface was swept off.

[0043] 2.3 Making glass slides

[0044] Weigh (4.0 ± 0.000 2) g of a mixture of lithium tetraborate and lithium metaborate flux and spread it evenly in a platinum crucible. Place the pre-melted sample melt into the platinum crucible, and evenly add 10–15 drops of lithium bromide release agent. Place the crucible in a pre-programmed high-frequency furnace for melting, and then cool. Pour out the glass slide, using the side closest to the bottom of the crucible as the irradiation surface, and perform spectral measurements.

[0045] 2.4 Measurement

[0046] Place the sample in the sample box. In the testing software, select the pre-edited method, enter the sample name and corresponding sample location, select "Unknown Sample" as the sample type, and click "Apply." A sample testing interface will pop up; click "Start" to begin testing the sample. Simultaneously analyze standard samples with similar content. The measured value of the standard sample is less than... If the deviation is within the allowable range, the sample measurement can only proceed after the cause has been investigated; if the results of parallel samples are less than the allowable deviation, the analytical results should be reported as the average value. Otherwise, the measurement should be performed again.

[0047] 2.5 Calibration Curve Plotting

[0048] Prepare glass slides using certified reference materials and measure their strength using a testing machine. Plot a series of working curves with concentration on the x-axis and strength on the y-axis. Alternatively, standard working curves can be plotted by chemically determining the values ​​of production samples and then following the steps described above. At least five points should be used when plotting the curves.

[0049] 2.6 Standardization of Working Curves

[0050] Perform standard sample check analysis on the instrument according to the instrument operating procedures. If the difference between the average measured value of each element in the standard sample and the standard value is less than 1 times the interlaboratory tolerance or reproducibility standard deviation, the instrument is considered to be normally standardized and the standard sample analysis can proceed. If the difference exceeds 1 times the interlaboratory tolerance or reproducibility standard deviation, standardization needs to be repeated. Standardization uses two-point calibration, selecting one point in the high-range and one in the low-range of the measured element, taking into account all elements. Multiple elements can be calibrated using the same standard sample. The instrument system automatically calculates the α and β values ​​based on the calibration curve. If the α value is between 0.5 and 1.5 and β is within the set range, the system defaults to successful standardization; otherwise, the standardization operation is repeated.

[0051] 3 Results and Discussion

[0052] 3.1 Precision of the Method

[0053] The same sample was measured 10 times consecutively to verify the precision of the method, as shown in Table 2.

[0054] Table 2: Precision Experiment n=10

[0055]

[0056] As shown in Table 2 above, the RSDs are all less than 5%, indicating good precision.

[0057] 3.2 Accuracy of the Method

[0058] Standard samples were selected for measurement and compared with the standard values ​​of the standard substances, as shown in Table 3.

[0059] Table 3: Method Accuracy Experiment

[0060]

[0061] As can be seen from Table 3, the test results are all less than the allowable difference, therefore the invention can guarantee the accuracy of the test results.

[0062] 4. Conclusion

[0063] This invention uses graphite as a reaction liner for pre-oxidation and melting of the sample, followed by melting in a platinum crucible to prepare the glass slide. This successfully solves the problem of easy corrosion of the platinum crucible, extending its service life. Compared with chemical analysis methods, this method allows for the simultaneous detection of multiple elements through a single sample melting process, resulting in higher detection efficiency. Experimental data shows that this invention, using the same glass slide to determine multiple analytical elements, offers advantages such as simple and rapid operation, low analytical cost, and high accuracy and precision. It fully meets the needs of scientific research and production analysis and testing, while reducing wastewater discharge and environmental pollution.

[0064] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting the content of various elements in slag, characterized in that, The method includes the following steps: 1) Sample pre-melting; 2) Making glass slides; 3) Perform spectral analysis on the glass slide obtained in step 2) using a fluorescence spectrometer; in: In step 1), the sample is pre-melted using a mixed flux of lithium tetraborate and lithium metaborate and sodium nitrate to obtain a sample melt. In step 2), the sample melt is melted again using a mixed flux of lithium tetraborate and lithium metaborate to obtain the glass sheet; The elements in the slag include: CaO, SiO2, MgO, Al2O3, MnO, TiO2 and P2O5.

2. The method according to claim 1, characterized in that, In step 1), the pre-melting process is carried out in an alumina crucible with graphite powder as the reaction substrate.

3. The method according to claim 2, characterized in that, The pre-melting treatment conditions are: melting at 1000℃ for 30 minutes.

4. The method according to any one of claims 1-3, characterized in that, The ratio of lithium tetraborate to lithium metaborate in the mixed flux is 2:

1.

5. The method according to any one of claims 1-4, characterized in that, Step 1) is as follows: Weigh 0.4000g of the sample, mix (3.0±0.0002)g of lithium tetraborate and lithium metaborate flux, and (0.25±0.0002)g of sodium nitrate. Place the mixture into a 30 mL corundum crucible lined with graphite powder, and melt it in a high-temperature furnace at 1000℃ for 30 min. Remove the mixture, cool it, and obtain the sample melt.

6. The method according to any one of claims 1-5, characterized in that, Step 2) is as follows: Weigh (4.0±0.0002) g of lithium tetraborate and lithium metaborate mixed flux and spread it evenly in a platinum crucible. Place the pre-melted sample melt into the platinum crucible and add 10-15 drops of lithium bromide release agent evenly. Place the crucible into a high-frequency furnace with the program set, melt it, and then cool it to obtain the glass sheet.

7. The method according to any one of claims 1-6, characterized in that, Step 3) involves using the side of the glass slide closest to the bottom of the crucible as the irradiation surface and performing spectral detection using the fluorescence spectrometer.

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