An XRF test method for determining the components of fly ash and coal gangue extracts - Al / Si oxides

Abstract

The present invention belongs to the field of spectral analysis technology, and specifically relates to an XRF testing method for determining various components in fly ash and coal gangue extracts-Al / Si oxides. The testing method includes the following steps: S1, preparation of standard samples; S2, preparation of standard samples; S3, determination of standard samples; S4, establishment of application methods; S5, testing of samples to be tested. The present invention uses an XRF fluorescence spectrometer to develop and establish an Al / Si oxide component testing application method, which fully meets the component analysis of various products in the current fly ash and coal gangue extract-Al / Si oxide production process, is simple and accurate to operate, and has excellent accuracy and precision, which reserves great feasibility for the subsequent expansion of the scope of method testing.

Description

Technical Field

[0001] The invention belongs to the technical field of spectrum analysis, and in particular relates to an XRF testing method for determining various components in fly ash and coal gangue extracts-Al / Si oxides. Background Art

[0002] With the increasing depletion of global bauxite resources, the sustainable development of my country's aluminum industry faces severe challenges. The external dependence of bauxite resources has been rising year by year, which not only increases production costs, but also poses a potential threat to national economic security. In this context, it is particularly important to find and develop new sources of aluminum resources. As a rich production area of ​​high-aluminum coal, the Ordos Basin in Inner Mongolia has an alumina content of more than 50% in its fly ash. This discovery has opened up a new way for the high value-added utilization of fly ash. As bulk solid wastes, fly ash and coal gangue can be prepared and refined into aluminum silicon oxide by chemical methods, which can not only effectively alleviate the problem of bauxite resource shortage, but also realize the recycling of resources, which is in line with the "dual carbon" goals and the environmental protection policy requirements of local governments.

[0003] However, in the process of preparing aluminum silicon oxide from fly ash and coal gangue, precise control of the content of each component in the intermediate products of different process stages is the key to ensure stable operation of the process and product qualification. At present, the methods used in the market to determine the content of each element in fly ash mainly include chemical methods (such as titration) and inductively coupled plasma atomic emission spectrometry (ICP-OES method). Although these methods can meet the measurement needs to a certain extent, they have problems such as cumbersome operation, long time consumption and high cost, which are not conducive to large-scale industrial application. In particular, for the determination of Al / Si oxide, an extract from fly ash and coal gangue, there is currently no standard XRF fluorescence spectrometry and its supporting standard samples, which to a certain extent limits the application of XRF technology in this field.

[0004] Therefore, it is necessary to develop a detection method for determining the content of each element in fly ash, coal gangue extract - Al / Si oxide and intermediate products of each process stage, so as to solve the problems of cumbersome operation, single test index and low efficiency in the existing technology for testing the content of each element in fly ash, coal gangue extract and intermediate products of each process stage. Summary of the invention

[0005] The purpose of the present invention is to provide an XRF testing method for determining the various components in fly ash and coal gangue extracts - Al / Si oxides. By selecting standard samples of specific components and in order to better eliminate the matrix effect, a fusion method is combined to develop and establish an application method for XRF testing of various components that can be used to determine fly ash, coal gangue extracts - Al / Si oxides and intermediate products of various process stages, which is used to solve the problems raised in the above-mentioned background technology.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] An XRF testing method for determining various components in fly ash and coal gangue extracts-Al / Si oxides, comprising the following steps:

[0008] S1. Preparation of standard samples;

[0009] S2. Preparation of standard samples;

[0010] S3, determination of standard samples;

[0011] S4. Establishment of application methods;

[0012] S5. Testing the samples to be tested.

[0013] The standard samples are based on the components in fly ash and coal gangue extracts, including silicon dioxide, aluminum oxide, iron oxide, titanium oxide, potassium oxide, sodium oxide, calcium oxide, and magnesium oxide. The components are calibrated according to the relevant requirements of the national standard GB / T15000 for the development of standard samples to obtain a final series of multiple groups of standard samples.

[0014] The gradient ranges of the single elements (compounds) in the standard samples are: Al2O3 (26.59%~62.34%), SiO2 (30.07%~55.02%), Na2O (0.51%~0.74%), MgO (0.29%~1.28%), K2O (0.58%~1.93%), CaO (0.13%~1.00%; 2.81%~9.90%), Fe2O3 (0.32%~0.5%; 2.05%~5.66%), and TiO2 (0.98%~1.67%).

[0015] The preparation of the standard sample specifically includes the following steps:

[0016] A1. Burn the standard sample at 990-1010℃ for 1.5-2.5h to obtain the burned standard sample, and calculate the loss on ignition (LOI) of each standard sample.

[0017] A2. Mix the fluxes and burn them at 690-710° C. for 3.5-4.5 hours, then cool them to obtain the burned flux; clean the platinum crucible, mold and other containers with an ultrasonic cleaner, place them in an electric hot air drying oven, and bake them at 290-310° C. for more than 2 hours for standby use;

[0018] A3. Weigh the burned standard sample and burned flux, pour them into the baked platinum crucible and mix them evenly, place the platinum crucible and the mold in the melting furnace to melt, then pour the melt into the mold to form it. After cooling naturally to room temperature, take it out of the mold and note the sample name, and you will get a complete standard sample. Repeat the above preparation process for the remaining standard samples.

[0019] The flux is burned before use to avoid errors caused by different moisture absorption levels and purities of different batches of flux, thereby improving measurement accuracy.

[0020] Preferably, the flux includes one or more of lithium tetraborate, lithium metaborate, lithium fluoride, and lithium carbonate; further preferably, it is lithium tetraborate, lithium metaborate, lithium fluoride, and lithium carbonate.

[0021] Preferably, the mass ratio of anhydrous lithium tetraborate, lithium metaborate, lithium fluoride and lithium carbonate is (5-7):(1-3):(0.5-2):1; more preferably, it is 6:2:1:1.

[0022] The selection of four fluxes in a specific mass ratio can not only effectively eliminate the mineral effect and particle size effect of the sample, improve the accuracy and sensitivity of the test, but also ensure the repeatability of the test through its stability and consistency. This is because the four fluxes have a synergistic effect. Lithium tetraborate and lithium metaborate are between different lithium compounds in chemical composition, and their mixture can provide a wider range of chemical composition, thus adapting to more types of samples; at the same time, the addition of lithium fluoride and lithium carbonate can adjust the pH and ionic strength of the flux, affect the solubility of elements in the flux, and make more types of elements exist in the flux with higher solubility. In addition, they can react chemically with the oxides in the sample during the melting process to form a stable glass melt, reduce sample loss and contamination during the test, and thus improve the stability of the test. Therefore, the selection of these fluxes can significantly improve the accuracy and reliability of the XRF test method in the determination of each component in fly ash and coal gangue extracts.

[0023] Preferably, the mass ratio of the burned standard sample to the burned flux is 1:(9-11); further preferably, it is 1:10.

[0024] By controlling the mass ratio of the burned standard sample and the burned flux, the detection accuracy and stability can be improved. This may be because by controlling the mass ratio of the burned standard sample and the burned flux, it is not only helpful to optimize the distribution of elements in the melt, but also to allow the elements in the sample to exist in a more uniform and stable state, thereby reducing the measurement error caused by uneven element concentration. Moreover, the appropriate mass ratio can significantly reduce the matrix effect, that is, the influence of other elements in the sample on the measurement of the target element, which helps to improve the accuracy and sensitivity of the measurement. Furthermore, by adjusting the mass ratio, the mutual interference between different elements can be effectively reduced or avoided, ensuring that the measurement of each element can obtain accurate and independent results. In addition, good mass ratio control can also help improve the quality of the melt, reduce the generation of defects such as bubbles and cracks, and allow X-rays to penetrate the sample more smoothly, further enhancing the reliability and repeatability of the detection.

[0025] Preferably, the mass ratio of platinum to gold in the platinum crucible is 95:5.

[0026] In step A3, the specific melting process is: pre-oxidation treatment at 790-810° C. for 8-12 minutes, then heating to 1040-1060° C. for melting for 25-35 minutes and then shaking for 10 minutes.

[0027] The determination of the standard sample specifically includes the following steps: using an X-ray fluorescence spectrometer to test the content of each element in the standard sample, and setting different determination conditions for different elements.

[0028] The measurement conditions of Al, Si, Fe, Mg, Ti, K, Ca and Na are shown in Table 1. In Table 1, for example, Mg KA1-HS-Min, explanation is: element-spectral line-high sensitivity-trace component.

[0029] Table 1 XRF measurement conditions of each element

[0030]

[0031] In XRF analysis, different elements require specific measurement conditions to ensure the accuracy and sensitivity of the measurement results due to their unique atomic structure and physical properties. For example, the measurement of Al usually uses a voltage of 30kV and a current of 70mA, with a PET crystal and a gas flow counter, and selects the high-sensitivity Kα1 spectrum for measurement, which can maximize the signal intensity of aluminum and reduce background noise. For Si, although the voltage is the same, the current is increased to 80mA, and an XS-CEM crystal is used to better match the X-ray characteristics of silicon. Light elements such as Na and Mg require a higher current (100mA) and an XS-55 crystal suitable for light element X-ray energy to increase signal intensity. Medium-mass elements such as K, Ca, and Ti are measured at a voltage of 50kV, using a LiF200 crystal to provide good energy resolution. The heavy element Fe requires a higher voltage (60kV) and a scintillation counter, as well as a narrower collimator (0.23°) to reduce background noise and accurately measure. The optimization of these measurement conditions is based on a comprehensive consideration of each element's atomic number, ionization energy, X-ray fluorescence yield and other physical properties, aiming to improve measurement accuracy and sensitivity, reduce interference and errors, and thus ensure the reliability of XRF analysis results.

[0032] The establishment of the application method specifically includes the following steps:

[0033] B1. Select the standard sample with the highest content of each element for 2θ scanning and PHA analysis, select the peak position, set the background, and optimize the measurement conditions of the analytical spectrum;

[0034] B2. Analyze and optimize the selection of spectral line parameters, and set them in the order of scanning 2θ from small to large for each element;

[0035] B3. Measure multiple sets of standard samples, collect the measurement data, and draw the standard curve after calibration.

[0036] By establishing a specific application method, the content of Al / Si oxides and other elements in fly ash and coal gangue extracts can be accurately determined. By recording the 2θ scanning diagram and PHA analysis diagram, on the one hand, the diffraction peak position and peak shape characteristics of different elements in the sample can be clearly observed, and on the other hand, the electrical noise and high-order line interference in the pulse height distribution can be filtered, so that not only the most suitable peak position can be selected for subsequent element content analysis, but also the appropriate background can be set to reduce noise interference, and the measurement conditions of the analysis spectrum can be optimized to significantly improve the accuracy and precision of the measurement. Then, combined with the spectrum line parameters, such as peak height, peak width, etc., further analysis optimization is carried out to achieve higher measurement accuracy. In addition, according to the order of scanning 2θ angles of each element from small to large, it can ensure that the diffraction peak of each element can be quickly and accurately located in the subsequent measurement process. Preparing multiple sets of standard samples for measurement can accumulate sufficient measurement data, providing a solid foundation for subsequent analysis and calibration. Finally, calibration is carried out to ensure that it can show high accuracy and reliability in different concentration ranges.

[0037] The test of the sample to be tested specifically includes the following steps: selecting the sample to be tested, referring to steps S2-S3, preparing the sample to be tested in the same way as preparing the standard sample, and testing it using the application method described in step S4, and obtaining the content of each component according to the standard curve.

[0038] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0039] 1. The present invention provides an XRF testing method for determining various components in fly ash and coal gangue extracts - Al / Si oxides. The method uses self-developed standard samples, combined with XRF fluorescence spectrometry, and adopts a melting method to prepare samples to eliminate the matrix effect, thereby achieving rapid and accurate determination of various oxide components in fly ash and coal gangue extracts - Al / Si oxides. The method can determine the content of aluminum, silicon, titanium, and trace iron, calcium, sodium, magnesium, potassium and other elements in the intermediate products of each process section in the entire process of preparing aluminum silicon oxides from fly ash and coal gangue. Compared with traditional chemical methods and ICP-OES methods, this method is simple to operate, time-saving, and greatly improves the determination efficiency.

[0040] 2. The present invention selects four fluxes in a specific mass ratio, which can not only effectively eliminate the mineral effect and particle size effect of the sample, improve the accuracy and sensitivity of the test, but also ensure the repeatability of the test through its stability and consistency.

[0041] 3. The present invention uses XRF for testing, which is not only non-destructive to the sample, but also capable of simultaneously measuring multiple elements, significantly reducing the measurement cost. The development of self-developed standard samples also reduces the dependence on external standard samples, further reducing costs.

[0042] 4. The present invention can improve detection accuracy and stability by controlling the mass ratio of the burned standard sample and the burned flux.

[0043] 5. In the XRF analysis of the present invention, different elements require specific measurement conditions due to their unique atomic structures and physical properties to ensure the accuracy and sensitivity of the measurement results.

[0044] 6. The present invention can accurately determine the content of Al / Si oxides and other elements in fly ash and coal gangue extracts by establishing a specific application method.

[0045] 7. The testing method described in the present invention complies with the "dual carbon" goals and the environmental protection policy requirements of local governments, and helps promote the resource utilization of large solid wastes such as fly ash and coal gangue, reduce environmental pollution, and achieve energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below.

[0047] Figure 1 This is the Al2O3 standard curve diagram described in Example 1 of the present invention.

[0048] Figure 2 This is a standard curve diagram of SiO2 described in Example 1 of the present invention.

[0049] Figure 3 This is the Na2O standard curve diagram described in Example 1 of the present invention.

[0050] Figure 4 This is the MgO standard curve diagram described in Example 1 of the present invention.

[0051] Figure 5 This is the K2O standard curve diagram described in Example 1 of the present invention.

[0052] Figure 6 This is the CaO standard curve diagram described in Example 1 of the present invention.

[0053] Figure 7 This is the Fe2O3 standard curve diagram described in Example 1 of the present invention.

[0054] Figure 8 This is a standard curve diagram of TiO2 described in Example 1 of the present invention. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Example 1

[0057] This embodiment provides an XRF testing method for determining various components in fly ash and coal gangue extracts - Al / Si oxides, the steps are:

[0058] S1. Preparation of standard samples;

[0059] S2. Preparation of standard samples;

[0060] S3, determination of standard samples;

[0061] S4. Establishment of application methods;

[0062] S5. Testing the samples to be tested.

[0063] The standard samples are based on the components in fly ash and coal gangue extracts, including silicon dioxide, aluminum oxide, iron oxide, titanium oxide, potassium oxide, sodium oxide, calcium oxide, and magnesium oxide. The components of each component are calibrated according to the relevant requirements of the national standard GB / T15000 for the development of standard samples to obtain a final series of multiple groups of standard samples. The composition table of 11 groups of standard samples is shown in Table 2.

[0064] Table 2 11 groups of standard sample composition values

[0065]

[0066] The preparation steps of the standard sample are as follows:

[0067] A1. Place the standard sample at 1000℃ and burn it for 2h to obtain the burned standard sample, and calculate the loss on ignition (LOI) of each standard sample;

[0068] A2, after mixing the flux, calcining at 700°C for 4 hours and then cooling to obtain the calcined flux; cleaning the platinum crucible, mold and other containers with an ultrasonic cleaner, placing them in an electric heating blast drying oven, and baking them at 300°C for 3 hours for standby use;

[0069] A3. Weigh the burned standard sample and burned flux, pour them into the baked platinum crucible and mix them evenly, place the platinum crucible and the mold in the melting furnace to melt, then pour the melt into the mold to form it. After cooling naturally to room temperature, take it out of the mold and note the sample name, and you will get a complete standard sample. Repeat the above preparation process for the remaining standard samples.

[0070] The flux is lithium tetraborate, lithium metaborate, lithium fluoride and lithium carbonate, and the mass ratio is 6:2:1:1.

[0071] The mass ratio of the burned standard sample to the burned flux is 1:10.

[0072] The mass ratio of platinum to gold in the platinum crucible is 95:5.

[0073] In step A3, the specific melting process is: pre-oxidation treatment at 800° C. for 10 minutes, then heating to 1050° C. for melting for 30 minutes and then shaking for 10 minutes.

[0074] The determination of the standard sample comprises the following steps: using an X-ray fluorescence spectrometer to test the content of each element in the standard sample, and setting different determination conditions for different elements.

[0075] The measurement conditions of Al, Si, Fe, Mg, Ti, K, Ca and Na are shown in Table 3. In Table 3, for example, Mg KA1-HS-Min, explanation is: element-spectral line-high sensitivity-trace component.

[0076] Table 3 XRF measurement conditions of each element

[0077]

[0078] The establishment of the application method specifically includes the following steps:

[0079] B1. Select the standard sample with the highest content of each element for 2θ scanning and PHA analysis, select the peak position, set the background, and optimize the measurement conditions of the analytical spectrum;

[0080] B2. Analyze and optimize the selection of spectral line parameters, and set them in the order of scanning 2θ from small to large for each element;

[0081] B3. Measure multiple groups of standard samples, collect measurement data, and draw standard curves after calibration; standard curves for Al2O3, SiO2, Na2O, MgO, K2O, CaO, Fe2O3, and TiO2 are shown in the table below. Figure 1 to Figure 8 ; Standard curve equation and correlation coefficient, see Table 4.

[0082] Table 4 Standard curve equations and correlation coefficients of each component

[0083]

[0084] The test of the sample to be tested comprises the following steps: selecting the sample to be tested, and preparing the sample piece to be tested in the same manner as preparing the standard sample piece with reference to steps S2-S3, and testing it using the application method described in step S4, and obtaining the content of each component according to the standard curve.

[0085] The samples to be tested were 3 groups of 11 groups of standard samples randomly selected, and the average value and standard deviation were used for analysis and evaluation. The results are shown in Table 5.

[0086] Table 5 Results of accuracy and precision tests

[0087]

[0088] Example 2

[0089] The difference between this embodiment and embodiment 1 is that the samples to be tested are fly ash and coal gangue extracts - the final product of Al / Si oxide, a series of aluminum silicon oxide (Al / Si) samples. Three groups of unknown experimental samples of the Al / Si series are randomly selected, and the average value and standard deviation are used for analysis and evaluation. The results are shown in Table 6.

[0090] Table 6 Trueness and precision test results

[0091]

[0092] It can be seen from Examples 1 to 2 that the XRF testing method for determining the various components in fly ash and coal gangue extracts - Al / Si oxides described in the present invention, uses self-developed standard samples, combined with XRF fluorescence spectroscopy, and adopts a melting method to prepare samples to eliminate the matrix effect, thereby achieving rapid and accurate determination of the various oxide components in fly ash and coal gangue extracts - Al / Si oxides, and can determine the content of aluminum, silicon, titanium and trace amounts of iron, calcium, sodium, magnesium, potassium and other elements in the intermediate products of each process section in the entire process of preparing aluminum silicon oxides from fly ash and coal gangue.

[0093] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An XRF testing method for determining the components of fly ash and coal gangue extracts - Al / Si oxides, characterized in that: The following steps are involved: S1. Preparation of standard samples; S2. Preparation of standard samples; S3. Determination of standard samples; S4. Establishment of application methods; S5. Testing of samples to be tested; The standard samples are based on the components in fly ash and coal gangue extracts, including silicon dioxide, aluminum oxide, iron oxide, titanium oxide, potassium oxide, sodium oxide, calcium oxide, and magnesium oxide. The components are calibrated according to the relevant requirements of the national standard GB / T 15000 for the development of standard samples to obtain a final series of multiple groups of standard samples; The preparation of the standard sample specifically includes the following steps: A1. Burn the standard sample at 990-1010℃ for 1.5-2.5h to obtain the burned standard sample, and calculate the burning loss of each standard sample; A2, after mixing the flux, calcine at 690-710°C for 3.5-4.5h and then cool to obtain the calcined flux; after cleaning the platinum crucible and the mold container with an ultrasonic cleaner, place them in an electric heating blast drying oven and bake them at 290-310°C for more than 2h for standby use; A3. Weigh the burned standard sample and burned flux, pour them into the baked platinum crucible and mix them evenly, place the platinum crucible and the mold in the melting furnace to melt, then pour the melt into the mold to form, cool it naturally to room temperature, take it out of the mold, note the sample name, and you will get a complete standard sample; repeat the above preparation process for the remaining standard samples; The flux is lithium tetraborate, lithium metaborate, lithium fluoride, and lithium carbonate, with a mass ratio of 6:2:1:1; The gradient ranges of the compounds in the standard sample are: Al2O3: 26.59%~62.34%, SiO2: 30.07%~55.02%, Na2O: 0.51%~0.74%, MgO: 0.29%~1.28%, K2O: 0.58%~1.93%, CaO: 0.13%~1.00%, 2.81%~9.90%, Fe2O3: 0.32%~0.5%, 2.05%~5.66%, TiO2: 0.98%~1.67%; The establishment of the application method specifically includes the following steps: B1. Select the standard sample with the highest content of each element for 2θ scanning and PHA analysis, select the peak position, set the background, and optimize the measurement conditions of the analytical spectrum; B2. Analyze and optimize the selection of spectral line parameters, and set them in the order of scanning 2θ from small to large for each element; B3. Measure multiple sets of standard samples, collect measurement data, and draw standard curves after calibration.

2. The XRF testing method for determining the components in fly ash and coal gangue extracts-Al / Si oxides according to claim 1, characterized in that: The mass ratio of the burned standard sample to the burned flux is 1:9-11.

3. The XRF testing method for determining the components in fly ash and coal gangue extracts-Al / Si oxides according to claim 1, characterized in that: The mass ratio of platinum to gold in the platinum crucible is 95:

5.

4. The XRF testing method for determining each component in fly ash and coal gangue extracts-Al / Si oxides according to claim 1, characterized in that: The determination of the standard sample specifically includes the following steps: using an X-ray fluorescence spectrometer to test the content of each element in the standard sample, and setting different determination conditions for different elements.

5. The XRF testing method for determining each component in fly ash and coal gangue extracts-Al / Si oxides according to claim 1, characterized in that: The test of the sample to be tested specifically includes the following steps: selecting the sample to be tested, referring to steps S2-S3, preparing the sample to be tested in the same way as preparing the standard sample, and testing it using the application method described in step S4, and obtaining the content of each component according to the standard curve, and obtaining the content of each component according to the standard curve.

6. The XRF testing method for determining each component in fly ash and coal gangue extracts-Al / Si oxides according to claim 1, characterized in that: In step A3, the specific melting process is: pre-oxidation treatment at 790-810° C. for 8-12 minutes, then heating to 1040-1060° C. for melting for 25-35 minutes and then shaking for 10 minutes.

7. An application of the XRF testing method for determining the components of fly ash and coal gangue extracts - Al / Si oxides according to any one of claims 1 to 6 in the field of fly ash and coal gangue bulk solid waste.

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