Method for detecting TiC in furnace front carbide slag

Abstract

The invention belongs to the field of chemistry, and relates to a method for detecting TiC in stokehole carbide slag, which comprises the following steps: S10, establishment of a standard working curve: (a) uniformly mixing an internal standard substance Y2O3 with a series of carbide slag standard samples with known TiC content according to a fixed mass ratio to prepare a series of mixed standard samples; (b) respectively scanning the mixed standard samples by adopting an X-ray diffractometer under the same test condition to obtain corresponding X-ray diffraction patterns; (c) identifying and measuring the characteristic diffraction peak intensity ITiC of TiC and the characteristic diffraction peak intensity IY2O3 of the internal standard substance Y2O3; (d) calculating the strength ratio Ri = ITiC / IY2O3 corresponding to each standard sample; (e) carrying out linear fitting to obtain a standard working curve; and S20, determining the sample to be detected. The detection method is simple, convenient and high in accuracy.

Description

Technical Field

[0001] This invention belongs to the field of chemistry and relates to a method for detecting TiC in pre-furnace carbonization slag. Background Technology

[0002] The Panxi region of Sichuan Province is rich in titanium resources. Through the traditional blast furnace ironmaking-converter steelmaking process, most of the titanium ends up in the blast furnace slag, which contains 20%–26% TiO2. Many domestic research institutions have conducted research on various titanium extraction technologies from blast furnace slag, such as producing silicon-titanium composite alloys and manufacturing slag microcrystalline glass. However, these methods have limited processing capacity and cannot fundamentally solve the problem of comprehensive utilization of titanium-containing blast furnace slag. Currently, the process route of "high-temperature carbonization-low-temperature chlorination to produce TiCl4" from high-titanium blast furnace slag is the most promising technology for industrialization.

[0003] High-temperature carbonization is a process that uses an electric furnace to smelt high-titanium blast furnace slag. Specifically, TiO2 in the slag is reduced with carbon powder. As smelting progresses, TiO2 gradually converts to TiC. Near the end of smelting, the TiC content in the slag is approximately 15%, hence the name "carbonized slag." The determination of TiC content in carbonized slag currently employs chemical analysis methods, including spectrophotometry, X-ray fluorescence spectrometry, and other processing methods. For example, Chinese patent CN112266020B addresses the problem in existing methods for determining titanium carbide in carbonized slag that suffer from inaccurate results and poor reproducibility due to the easy hydrolysis of titanium. This invention provides a more accurate method for determining titanium carbide in carbonized slag. EDTA solution is added when dissolving the carbonized slag sample, and the solution volume is maintained at 25–40 mL. This method effectively prevents the re-hydrolysis of titanium ions generated from the decomposition of titanium carbide by nitric acid, greatly increasing the operability of the analytical method and thus improving the accuracy of the analysis. The chemical method used has several drawbacks: it requires several steps, including sample preparation, dissolution, and separation, and the measurement often takes more than 2 hours; the analytical results cannot be fed back in a timely manner to guide the control of high-temperature carbonization smelting; the chemical analysis sample is small, with a measurement amount of only 0.1~0.2g, and the error is relatively large when analyzing carbonized slag with segregation; in addition, the analysis process requires a large amount of acidic solutions, such as hydrofluoric acid and nitric acid, which can easily pollute the environment. Therefore, there is a need to find a rapid method for detecting the TiC content in carbonized slag to guide the determination of the end point of the furnace smelting process. Summary of the Invention

[0004] In view of this, the present invention proposes a method for detecting TiC in pre-furnace carbide slag, which aims to use the internal standard method for XRD quantitative analysis of carbide slag, and solve the technical problems that the existing methods for determining TiC content in carbide slag are time-consuming and cannot be used to guide the determination of the end point of pre-furnace smelting.

[0005] To solve at least one of the above-mentioned technical problems, the present invention adopts the following technical solution: According to the present invention, a method for detecting TiC in pre-furnace carburized slag is provided, comprising the following steps: S10, establishing a standard working curve: (a) uniformly mixing the internal standard Y2O3 with a series of carburized slag standard samples with known TiC content at a fixed mass ratio to obtain a series of mixed standard samples; (b) scanning the mixed standard samples respectively using an X-ray diffractometer under the same test conditions to obtain the corresponding X-ray diffraction patterns; (c) identifying and measuring the characteristic diffraction peak intensity I of TiC from each X-ray diffraction pattern. TiC The characteristic diffraction peak intensity I of the internal standard Y2O3 Y2O3 (d) Calculate the strength ratio R corresponding to each standard sample. i =I TiC / I Y2O3 (e) Using the known TiC content as the abscissa and the corresponding strength ratio R... i Using the vertical axis as the ordinate, perform linear fitting to obtain the standard working curve; S20, determination of the sample to be tested: (f) Mix the internal standard Y2O3 and the carbide slag sample to be tested uniformly at the same fixed mass ratio as in step (a) to obtain the mixed sample to be tested; (g) Under the same test conditions as in step (b), perform X-ray diffraction scanning on the mixed sample to be tested to obtain its X-ray diffraction pattern; (h) Measure the characteristic diffraction peak intensity I of TiC from the X-ray diffraction pattern of the mixed sample to be tested. TiC The characteristic diffraction peak intensity I of Y2O3 Y2O3 And calculate its strength ratio R x (i) The strength ratio R x Substitute the input into the standard working curve to calculate the TiC content in the carbonized slag sample to be tested.

[0006] According to one embodiment of the present invention, in steps (a) and (f), the fixed mass ratio of the carbonized slag sample to the internal standard Y2O3 is (2~3):1.

[0007] According to one embodiment of the present invention, in step (a), the TiC content in the series of carbonized slag standard samples covers a mass fraction range of 2% to 15%.

[0008] According to one embodiment of the present invention, the series of carbonized slag standard samples includes at least five different content points among TiC mass fractions of 2%, 4%, 6%, 8%, 10%, 12%, 14% and 15%.

[0009] According to one embodiment of the present invention, in steps (c) and (h), the characteristic diffraction peaks of TiC are selected from diffraction peaks with a 2θ of 41.9° ± 0.2°.

[0010] According to one embodiment of the present invention, in steps (c) and (h), the characteristic diffraction peaks of the internal standard Y2O3 are selected from diffraction peaks with a 2θ of 48.5° ± 0.2°.

[0011] According to one embodiment of the present invention, in steps (b) and (g), the same test conditions include: the scanning range 2θ of the X-ray diffractometer is 10° to 90°.

[0012] According to one embodiment of the present invention, in steps (a) and (f), the uniform mixing includes thorough grinding in a mortar.

[0013] According to one embodiment of the present invention, in steps (a) and (f), the prepared mixed powder sample needs to be scraped flat after being loaded into the sample holder to ensure that the flatness of the test surface is consistent.

[0014] According to one embodiment of the present invention, the internal standard Y2O3 is an analytical grade reagent.

[0015] By adopting the above technical solution, the present invention has at least one of the following advantages compared with the prior art: (1) The internal standard method was used for XRD quantitative analysis of carbide slag, which made the determination results faster and shortened the analysis time of TiC in carbide slag from 2h to 15min; (2) The method of the present invention simplifies the analysis steps, avoids the use of solvents such as hydrofluoric acid and sulfuric acid, as well as operations such as water baths and filtration, improves the operating conditions, reduces labor intensity, and greatly shortens the analysis process; (3) On the one hand, analytical grade Y2O3 is selected as the exclusive internal standard, with extremely low impurity content and no interference from impurity peaks. On the other hand, the intensity ratio is calculated by using the internal standard method, which effectively offsets the systematic errors caused by sample loading state, grinding fineness, small fluctuations of the instrument, and sample absorption effect, so that the detection results are accurate and the error is highly controllable. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart illustrating a method for detecting TiC in pre-furnace carbonization slag according to an embodiment of the present invention; Figure 2 In one embodiment of the present invention, the strength ratio Ri (I) TiC / I Y2O3The standard working curve of TiC content. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0019] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0020] According to the present invention, such as Figure 1 As shown, a method for detecting TiC in pre-furnace carbonization slag is proposed, which mainly includes the following steps: S10, Establishment of the standard working curve: (a) A series of mixed standard samples were prepared by uniformly mixing internal standard Y2O3 with a series of carbide slag standard samples with known TiC content at a fixed mass ratio. (b) Using an X-ray diffractometer under the same test conditions, the mixed standard samples were scanned to obtain the corresponding X-ray diffraction patterns; (c) Identify and measure the intensity of the characteristic diffraction peaks I of TiC from each X-ray diffraction pattern. TiC The characteristic diffraction peak intensity I of the internal standard Y2O3 Y2O3 ; (d) Calculate the strength ratio R corresponding to each standard sample. i =I TiC / I Y2O3 ; (e) Plot the known TiC content on the x-axis and the corresponding strength ratio R. i Using the vertical axis as the ordinate, perform linear fitting to obtain the standard working curve; S20, Determination of the sample to be tested: (f) Mix the internal standard Y2O3 with the carbonized slag sample to be tested at the same fixed mass ratio as in step (a) to obtain the mixed sample to be tested; (g) Under the same test conditions as in step (b), perform X-ray diffraction scanning on the mixed sample to be tested to obtain its X-ray diffraction pattern; (h) Measure the intensity I of the characteristic diffraction peak of TiC from the X-ray diffraction pattern of the mixed sample to be tested. TiC The characteristic diffraction peak intensity I of Y2O3Y2O3 And calculate its strength ratio R x ; (i) The strength ratio R x Substitute the values ​​into the standard working curve to calculate the TiC content in the carbonized slag sample to be tested.

[0021] Y₂O₃ (yttrium oxide) possesses excellent chemical inertness, making it highly stable in the carbide slag system. In step (a), Y₂O₃ is selected as an internal standard, which will not react with other components in the slag, such as Fe, Si, Ca oxides, or carbides, ensuring its phase purity and consistency in all samples. In the embodiments of this invention, the fixed mass ratio of the carbide slag sample to the internal standard Y₂O₃ is (2~3):1, preferably 4:1. If the internal standard is too small, its diffraction peak intensity will be too weak, resulting in a large measurement error; if the internal standard is too large, it will excessively dilute the TiC phase to be measured, leading to a weak TiC peak intensity. The above ratio of this invention aims to ensure that the intensities of the TiC peak and the Y₂O₃ peak are on the same order of magnitude and within the optimal measurement range of the instrument, thereby reducing the relative error of the intensity ratio.

[0022] The TiC content in the pre-furnace carburized slag produced during electric arc furnace smelting is relatively low. In embodiments of the present invention, the TiC content in a series of standard carburized slag samples from step (a) covers a mass fraction range of 2% to 15%, for example including at least five different content points among TiC mass fractions of 2%, 4%, 6%, 8%, 10%, 12%, 14%, and 15%. Alternatively, those skilled in the art can adjust the TiC content according to actual operating conditions to match the needs of actual production monitoring.

[0023] In steps (a) and (f), uniform mixing may include thorough grinding in a mortar to ensure that TiC and Y₂O₃ particles are uniformly distributed at the microscale, so that any small area irradiated by X-rays has the same phase ratio, thereby obtaining representative diffraction data. After the prepared mixed powder sample is loaded into the sample holder, it needs to be leveled to ensure consistent flatness of the test surface, minimizing intensity fluctuations caused by sample loading differences and improving the accuracy of the detection results. Preferably, the internal standard Y₂O₃ is an analytical grade reagent, meaning that the Y₂O₃ reagent has high purity and low impurity content, so as not to significantly interfere with the results of chemical analysis.

[0024] In steps (b) and (g), the scanning range 2θ of the X-ray diffractometer is 10° to 90°.

[0025] In steps (c) and (h), the characteristic diffraction peaks of TiC can be selected from the diffraction peaks with a 2θ of 41.9° ± 0.2°, preferably 41.9°. This range contains one of the strongest or second strongest diffraction peaks of TiC, has high intensity, is less susceptible to interference, and can guarantee I TiCThe signal-to-noise ratio (SNR) of the internal standard Y₂O₃ was measured. The characteristic diffraction peaks of the internal standard Y₂O₃ were selected from diffraction peaks with a 2θ of 48.5° ± 0.2°, preferably 48.5°. On the one hand, the stable crystal structure of Y₂O₃ produces high-intensity, sharp diffraction peaks, facilitating accurate measurement. The characteristic peaks of Y₂O₃ within this range are clearly distinguishable from the diffraction peaks of other common slag components such as CaO, SiO₂, and Ca₂SiO₄, avoiding peak overlap interference and ensuring the signal-to-noise ratio (SNR). Y2O3 The accuracy of the measurement; on the other hand, its angle is close to that of the characteristic peak of TiC (41.9°), and the difference in diffraction conditions between the two is small during XRD scanning, which can further enhance the stability of the ratio R.

[0026] The following are specific embodiments of the method for detecting TiC in pre-furnace carbonization slag according to the present invention.

[0027] Example 1 The detection equipment for the TiC detection method in the furnace front carbonization slag of this embodiment is a Thermo Eqinox 100 benchtop X-ray diffractometer manufactured by Thermo Fisher Scientific, paired with the analysis software Match. The test conditions are: Cu-Ka, 2θ range 10~90°, tube voltage 40kV, tube current 10mA.

[0028] Weigh 10.000g of each of 10 carbide slag samples containing different known TiC contents. The specific titanium carbide contents in the slags are 6.68%, 8.28%, 9.72%, 10.44%, 11.90%, 12.09%, 13.65%, 13.75%, 14.41%, and 14.80%, respectively. Accurately weigh 2.500g of Y2O3 (analytical grade) and mix and grind them thoroughly and evenly in a mortar. Then, load the evenly mixed powder into an XRD sample holder, gently leveling it with a glass slide during loading, and ensuring a consistent surface flatness after loading.

[0029] Using an X-ray diffraction analyzer, under the following parameters: Cu-Ka, 2θ range 10~90°, tube voltage 40kV and tube current 10mA, all standard samples were scanned sequentially to obtain the diffraction patterns of the samples.

[0030] Process the data and plot the standard diffraction curves. Process the spectra to identify and calibrate the characteristic diffraction peaks of TiC and Y₂O₃. For TiC, the peak with 2θ of 41.9° was selected as the chosen diffraction peak; for the internal standard Y₂O₃, the peak with 2θ of 48.5° was selected as the chosen diffraction peak. Measure the net peak height of the selected peaks. Record: (1) I TiC The intensity of the characteristic peak of TiC in the carbonized slag to be tested; (2) I Y2O3The intensity of the characteristic peak of the internal standard Y2O3; Then, for each standard sample, the intensity ratio R of the selected peak is calculated. i =I TiC / I Y2O3 Using the known mass fraction W of TiC in the standard sample... i The x-axis represents the intensity ratio R. i Using the vertical axis as the ordinate, a scatter plot is drawn, and linear fitting is performed using the least squares method to obtain the working curve equation, i.e., the standard working curve.

[0031] Selected diffraction peak intensity I TiC I Y2O3 And calculate the intensity ratio R of the selected peak i =I TiC / I Y2O3 All are listed in Table 1, with the known mass fraction W of TiC in the standard sample. i The x-axis represents the intensity ratio R. i Using the ordinate as the vertical axis, a scatter plot was drawn. Linear fitting was performed using the least squares method to obtain the working curve equation: y = 0.038x + 0.109, with a coefficient of determination R0. 2 =98.84%, where x is the TiC content (%) and y is the strength ratio R. i =I TiC / I Y2O3 The specific standard curve is as follows: Figure 2 As shown in Table 1, the comparison between the fitted values ​​and the chemical analysis values ​​is also shown in Table 1. The maximum average deviation of the TiC content calculated by fitting the standard curve using the internal standard method and chemical detection results is 0.23%, which meets the detection requirements for titanium carbide content in the furnace-front carbonized slag.

[0032] Table 1. Results of Standard Curve Fitting and TiC Content Calculation

[0033] Determination of unknown samples: The same fixed proportion of internal standard was added to the carbonized slag sample powder to be tested, ensuring that the mixing and grinding conditions were exactly the same as those used in the preparation of the standard sample. The XRD pattern of the sample was acquired under the same instrument and parameter conditions. The obtained pattern underwent the same data processing as the standard sample to obtain I0. TiC and I Y2O3 Calculate the R of the sample to be tested. x Substitute the value into the working curve to solve for the mass fraction of TiC in the sample to be tested.

[0034] Table 2 shows the difference between the TiC content calculated based on the standard working curve and the TiC content determined by chemical analysis after XRD detection of the test sample using the internal standard method. The entire test was completed in 15 minutes. It can be seen that the detection error is small, with the absolute error within 0.2%, which meets the detection accuracy requirements for determining the end point of furnace smelting.

[0035] Table 2. Verification of the accuracy of the detection method

[0036] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications or equivalent substitutions to the present invention without departing from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

[0037] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of the present invention is limited to these examples; within the framework of the embodiments of the present invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention.

Claims

1. A method for detecting TiC in pre-furnace carbonization slag, characterized in that, Includes the following steps: S10, Establishment of standard working curves: (a) A series of mixed standard samples were prepared by uniformly mixing internal standard Y2O3 with a series of carbide slag standard samples with known TiC content at a fixed mass ratio. (b) The mixed standard sample was scanned using an X-ray diffractometer under the same test conditions to obtain the corresponding X-ray diffraction patterns; (c) Identify and measure the intensity of the characteristic diffraction peaks I of TiC from each X-ray diffraction pattern. TiC The characteristic diffraction peak intensity I of the internal standard Y2O3 Y2O3 ; (d) Calculate the strength ratio R corresponding to each standard sample. i =I TiC / I Y2O3 ; (e) Using the known TiC content as the abscissa and the corresponding strength ratio R... i Using the vertical axis as the ordinate, perform linear fitting to obtain the standard working curve; S20, Determination of the sample to be tested: (f) The internal standard Y2O3 and the carbonized slag sample to be tested are uniformly mixed at the same fixed mass ratio as in step (a) to obtain the mixed sample to be tested; (g) Under the same test conditions as in step (b), the mixed sample to be tested is subjected to X-ray diffraction scanning to obtain its X-ray diffraction pattern; (h) Measure the intensity I of the characteristic diffraction peak of TiC from the X-ray diffraction pattern of the mixed sample to be tested. TiC The characteristic diffraction peak intensity I of Y2O3 Y2O3 And calculate its strength ratio R x ; (i) The strength ratio R x Substitute the input into the standard working curve to calculate the TiC content in the carbonized slag sample to be tested.

2. The detection method according to claim 1, characterized in that, In steps (a) and (f), the fixed mass ratio of the carbonized slag sample to the internal standard Y2O3 is (2~3):

1.

3. The detection method according to claim 1, characterized in that, In step (a), the TiC content in the series of carbonized slag standard samples covers a mass fraction range of 2% to 15%.

4. The detection method according to claim 3, characterized in that, The series of carbonized slag standard samples includes at least five different content points among TiC mass fractions of 2%, 4%, 6%, 8%, 10%, 12%, 14%, and 15%.

5. The detection method according to claim 1, characterized in that, In steps (c) and (h), the characteristic diffraction peaks of TiC are selected from diffraction peaks with a 2θ of 41.9° ± 0.2°.

6. The detection method according to claim 1, characterized in that, In steps (c) and (h), the characteristic diffraction peaks of the internal standard Y2O3 are selected from diffraction peaks with a 2θ of 48.5° ± 0.2°.

7. The detection method according to claim 1, characterized in that, In steps (b) and (g), the same test conditions include: the scanning range 2θ of the X-ray diffractometer is 10° to 90°.

8. The detection method according to claim 1, characterized in that, In steps (a) and (f), the uniform mixing includes thorough grinding in a mortar.

9. The detection method according to claim 1, characterized in that, In steps (a) and (f), the prepared mixed powder sample needs to be scraped flat after being loaded into the sample holder to ensure that the flatness of the test surface is consistent.

10. The detection method according to claim 1, characterized in that, The internal standard Y2O3 was an analytical grade reagent.

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