A method and system for determining element content

Abstract

The present invention discloses a method and system for determining element content, and relates to the field of material composition detection. The method comprises: using an X-ray fluorescence analysis device to measure the content of at least one preset internal standard element in a material to be tested; using a laser induced breakdown spectroscopy analysis device to measure the characteristic spectral lines of the preset internal standard element and the element to be tested in the material to be tested; determining the conversion function between the characteristic spectral line and the content of each element to be tested and the corresponding preset internal standard element; and determining the content of each element to be tested according to the conversion function between the characteristic spectral line and the content of each element to be tested and the corresponding preset internal standard element. The present invention improves the accuracy of element content detection.

Description

Technical Field

[0001] The present invention relates to the technical field of material component detection, and in particular to a method and system for determining element content. Background Art

[0002] Laser induced breakdown spectroscopy (LIBS) can qualitatively or semi-quantitatively analyze the elemental composition of different substances. It is easy to use, quick to obtain results, and can analyze most elemental components. The principle is to use a short-term high-energy laser pulse to irradiate the sample, instantly generate high temperature at the irradiated point, thereby forming a plasma. By measuring the spectrum emitted by the plasma, it is possible to obtain which elements are contained in the plasma and the content of the elements. The content of each element is related to the area of ​​its corresponding spectral line in the spectrum. However, this technology has some defects that limit its application. For example, the fluctuation of laser power affects the temperature of the plasma, and then affects the area of ​​the spectrum, which will affect the analysis of elemental content. The moisture in the substance will also affect the measurement. Some substances will produce volatile substances at high temperatures, such as coal. These volatile substances will affect the generation of plasma and its emission spectrum. These defects have greatly limited the application of LIBS in quantitative measurement.

[0003] X-ray fluorescence analysis (hereinafter referred to as XRF) is another elemental analysis technology with a long history and is currently widely used. It can be used to prepare samples for analysis of the measured material, or to analyze the element content of the material online. Its principle is to use radiation to irradiate the measured material to stimulate the characteristic X-rays of each element in the material. The energy of the characteristic X-rays of different elements is different. The energy spectrum of these characteristic X-rays is measured, and the content of the corresponding element can be analyzed based on the area of ​​different energy peaks in the energy spectrum. Compared with LIBS technology, XRF analysis results for many elements are more stable and accurate. However, due to theoretical limitations, XRF is suitable for analyzing elements with high atomic numbers, such as elements with atomic numbers greater than 19. This is because of the following reasons: (1) The higher the atomic number of the element, the higher the energy of its characteristic X-rays and the stronger its penetration ability. In this way, the depth of the sample that can be analyzed is greater and the representativeness of the measurement is higher. At the same time, the characteristic X-rays excited from the measured object pass through the air to reach the detector. The absorption of the air by the rays decreases as the energy of the X-rays increases. High-energy X-rays do not need to be vacuumed or filled with helium to reduce the influence of air. On the contrary, for elements with low atomic numbers, their characteristic X-rays are easily absorbed by the air. For example, the characteristic X-rays of elements C and O are easily absorbed by the air and the detector window. Therefore, it is necessary to evacuate the air and the detector window needs to be extremely thin. Therefore, it is very difficult to measure elements C and O using XRF, and H cannot produce characteristic X-rays. (2) The incident rays interact with the material being measured, which will produce characteristic X-rays or Auger electrons. The higher the atomic number, the greater the probability of producing characteristic X-rays and the smaller the probability of producing Auger electrons. Therefore, the sensitivity of measuring elements with high atomic numbers is higher. On the contrary, the yield of characteristic X-rays of elements with low atomic numbers decreases as the atomic number decreases.

[0004] In summary, XRF is suitable for measuring the content of high atomic number elements, while LIBS can measure low atomic number elements, such as H, C, N, O, Na, Mg, Al, Si, etc., which are often the main components of many commonly used minerals or materials, such as coal, cement, etc. However, due to various factors, the use of LIBS to measure element content cannot give stable quantitative results.

[0005] The internal standard method is a common method in component analysis. The usual internal standard method is to add a certain weight of pure substance as an internal standard to a certain amount of the sample to be analyzed and mix it thoroughly. Then, the sample containing the internal standard is subjected to chromatographic analysis. The peak area (or peak height) and relative correction factor of the internal standard and the component to be tested are measured respectively. The percentage content of the component to be tested in the sample can be calculated according to the formula. The internal standard method is a relatively accurate quantitative method in chromatographic analysis, especially when there is no standard control, this method is more superior.

[0006] The internal standard method is a commonly used quantitative method in chromatographic analysis. Its principle is to add a certain amount of known pure substance to the sample to be analyzed as an internal standard. The internal standard should have basically the same physical and chemical properties as other components in the sample to ensure that its behavior in the chromatographic system is as consistent as possible with the sample components. The amount of internal standard added is known, so the original concentration of the component to be measured in the sample can be calculated by measuring the peak area or peak height of the internal standard and the component to be measured, as well as their relative correction factors.

[0007] The existing technology of using the spectrum line of a certain element measured by the LIBS technology itself as the internal standard reference amount has a principle defect, which leads to a reduction in the effect of the internal standard method. If the content of a certain element in the object to be measured is not measured with the help of XRF technology, but only the spectrum line intensity of a certain element measured by LIBS itself is used as the internal standard reference amount, the ratio of the spectrum line intensity of the LIBS spectrum of other elements to the spectrum line intensity of the LIBS spectrum of the internal standard reference amount can be calculated, but the element content of the internal standard reference element itself cannot be accurately measured, or the accuracy of the internal standard reference amount itself cannot be improved by this internal standard method, which causes errors in the composition measurement of other elements based on the internal standard reference amount. If the sum of the mass percentage of all elements in the substance is 1, and the ratio of all other elements in the substance to the internal standard reference amount is known, the percentage content of each element can be calculated. However, the problem with this method is that the spectrum line intensity of all elements in the substance must be measured to meet and use the condition that the sum of the mass percentage of all elements in the substance is 1, and the content of each element can be calculated. In general applications, all elements of the material to be tested will not be measured, which requires the use of more frequency bands of spectral analysis instruments to increase costs. In addition, the spectra of some frequency bands are more susceptible to environmental influences, and LIBS is not sensitive to certain elements. These problems lead to the fact that in many cases, LIBS technology is not used or difficult to use to measure all elements in the material to be tested. Therefore, it is not possible to calculate the content of each element by measuring the ratio between all elements and the internal standard reference. If the LIBS technology cannot measure the ratio between all elements or most of the main elements and the internal standard reference, the so-called internal standard method cannot accurately give the content of the measured element, because first of all, the content of the internal standard element cannot be accurately known, and the measurement of the content of the internal standard element will be affected by the unstable characteristics of LIBS, which in turn affects the measurement of the content of other elements. Summary of the invention

[0008] The purpose of the present invention is to provide a method and system for determining element content, thereby improving the accuracy of element content detection.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] A method for determining element content, the method comprising:

[0011] Using an X-ray fluorescence analyzer to measure the content of at least one preset internal standard element in the material to be tested;

[0012] Using a laser induced breakdown spectroscopy analysis device to measure the characteristic spectral lines of the preset internal standard element and the element to be measured in the material to be measured;

[0013] Determine the conversion function between the characteristic spectrum line and the content of each element to be measured and the corresponding preset internal standard element;

[0014] The content of each element to be measured is determined according to a conversion function between a characteristic spectrum line and a corresponding preset internal standard element of each element to be measured.

[0015] Optionally, determining a conversion function between a characteristic spectrum line and a content of each element to be measured and a corresponding preset internal standard element specifically includes:

[0016] A laser induced breakdown spectroscopy analysis device is used to collect multiple groups of sample data about the mth element to be measured; each group of sample data includes the area of ​​a characteristic spectrum line of the mth element to be measured, the area of ​​a characteristic spectrum line of a preset internal standard element corresponding to the mth element to be measured, and the ratio of the content of the mth element to be measured to the corresponding preset internal standard element;

[0017] The plurality of groups of sample data are fitted to obtain a conversion function between the characteristic spectrum line and the content of the mth element to be measured and the corresponding preset internal standard element.

[0018] Optionally, fitting the multiple groups of sample data to obtain a conversion function between the mth element to be measured and the corresponding preset internal standard element with respect to the characteristic spectrum line and the content specifically includes:

[0019] The plurality of groups of sample data are fitted by least square fitting to obtain a conversion function between the mth element to be measured and the corresponding preset internal standard element with respect to the characteristic spectrum line and the content.

[0020] Optionally, the conversion function between the characteristic spectrum line and the content of each element to be measured and the corresponding preset internal standard element is expressed as:

[0021] C m / C 0j =A m ·(S m / S 0j ) 3 +B m ·(S m / S 0j ) 2 +D m ·S m / S 0j +E m ;

[0022] Among them, C m is the content of the mth element to be measured, C 0j is the content of the jth preset internal standard element, S m is the area of ​​the characteristic spectrum line of the mth element to be measured, S 0j is the characteristic spectral line area of ​​the jth preset internal standard element, A m , B m , D m and E m are all constants.

[0023] Optionally, the material to be tested is a mineral, and the preset internal standard element is Fe.

[0024] A system for determining element content, the system for determining element content applying the method for determining element content, the system for determining element content comprising: a transmission belt, a computing device, an X-ray fluorescence analysis device and a laser induced breakdown spectrometry analysis device, the X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device being arranged above the transmission belt, the transmission belt being used for transmitting a material to be tested, the X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device being connected to the computing device;

[0025] The X-ray fluorescence analysis device is used to measure the content of at least one preset internal standard element in the material to be tested on the transmission belt;

[0026] The laser induced breakdown spectroscopy analysis device is used to measure the characteristic spectral lines of the preset internal standard element and the element to be measured in the material to be measured on the transmission belt;

[0027] The calculation device is used to determine the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element; according to the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element, the content of each element to be measured is determined.

[0028] Optionally, the X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device are sequentially arranged above the transmission belt along the transmission direction of the transmission belt;

[0029] When the transmission belt is running, the computing device is used to delay the first measurement data transmitted by the X-ray fluorescence analysis device so that the material to be tested corresponding to the first measurement data after the delay processing and the second measurement data transmitted by the laser induced breakdown spectrometry analysis device is the material to be tested at the same position on the transmission belt; the first measurement data is the content of at least one preset internal standard element, and the second measurement data is the characteristic spectral lines of the preset internal standard element and the element to be tested.

[0030] Optionally, the X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device are arranged laterally above the transmission belt, and the transverse direction is a direction perpendicular to the transmission direction of the transmission belt; the irradiation area of ​​the laser induced breakdown spectrometry analysis device is contained in the irradiation area of ​​the X-ray fluorescence analysis device.

[0031] Optionally, the element content determination system further comprises an online moisture measurement device, the online moisture measurement device is connected to the computing device, and the online moisture measurement device is used to collect the moisture of the material to be measured on the transmission belt;

[0032] The calculation device is used for when the element to be measured is hydrogen, the content of hydrogen is the content after deducting the content of hydrogen in the water.

[0033] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] The present invention is based on the content of at least one preset internal standard element in the material to be tested measured by an X-ray fluorescence analysis device, and the characteristic spectral lines of the preset internal standard element and the element to be tested in the material to be tested measured by a laser induced breakdown spectroscopy analysis device. According to the conversion function between the characteristic spectral line and the content of each element to be tested and the corresponding preset internal standard element, the content of each element to be tested is determined, the element content measured by the X-ray fluorescence analysis device is used as the internal standard element, and the internal standard method is used to more accurately measure other element components, thereby improving the accuracy of element content detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic flow chart of a method for determining element content provided by an embodiment of the present invention;

[0037] Figure 2A schematic diagram of a first configuration of an X-ray fluorescence analysis device and a laser induced breakdown spectroscopy analysis device provided in an embodiment of the present invention;

[0038] Figure 3 A schematic diagram of a second configuration of an X-ray fluorescence analysis device and a laser induced breakdown spectroscopy analysis device provided in an embodiment of the present invention.

[0039] Explanation of symbols:

[0040] 1-X-ray fluorescence analysis device, 2-first area, 3-laser induced breakdown spectroscopy analysis device, 4-second area, 5-material to be tested, 6-transmission belt. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0042] The purpose of the present invention is to provide a method and system for determining element content, thereby improving the accuracy of element content detection.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] The present invention draws on the traditional internal standard method principle, but does not add quantitative known substances to the measured object, but uses XRF technology to measure the content of a certain element in the measured substance, which is referred to as an internal standard element here, and LIBS technology is also used, that is, a short-time high-energy laser pulse is used to irradiate the sample, and a high temperature is instantly generated on the irradiated point, so that a plasma is formed on the irradiated point, and a spectrometer is used to measure the spectrum emitted by the plasma, and the frequencies of the emitted light of different elements in the plasma are different, so there are corresponding different spectral lines on the spectrum, and there are corresponding spectral lines for the internal standard element. The spectrometer is usually connected to a computer (connection mode has USB or network, etc.), and after the spectral data is collected by the computer, the spectral data can be analyzed and calculated. Therefore, the spectral line area (or spectral line intensity) of the internal standard element can be calculated from the spectral data, and the spectral line area of ​​other elements of interest in the spectrum is calculated by the same method, and then the ratio of the spectral line area of ​​these other elements to the spectral line area of ​​the internal standard element is calculated, and then these ratios are adjusted by different conversion factors. The basis for the need to use conversion factor calibration is that spectral lines of different frequencies may be attenuated differently on the path through the air to the spectrometer, and the efficiency of characteristic light excited by different elements is different, so it is necessary to set a conversion factor, which is obtained by fitting experimental measurement data. It can be considered that the corrected ratio of the spectral line area of ​​each element to the spectral line area of ​​the internal standard element and the ratio of the content of each element to the content of the internal standard element have a monotonic relationship. In this way, the content of each element in the object being measured can be calculated based on the content of the internal standard element measured by XRF and the ratio of the spectral line area of ​​each element to the spectral line area of ​​the internal standard element measured by LIBS.

[0045] The present invention originates from such a basic idea: although the spectrum measured by LIBS will be affected by external changes such as laser power change, material moisture, material volatile matter, material particle size, etc., the spectrum lines of each element in the same spectrum will show certain synergistic changes within a certain range to the above-mentioned influences. For example, each spectrum line may be affected to increase or decrease together, or some spectrum lines may be affected to show opposite changes. By using the internal standard method, the relationship between the spectrum line intensity of other elements and the spectrum line intensity of the internal standard element is established through experiments to reduce external influences. The content of the internal standard element can be measured by the more reliable XRF technology, thereby improving the measurement accuracy and stability of LIBS. Using the more reliable measurement technology XRF to measure the content of a certain element and use it as the internal standard reference amount will truly play the role of the internal standard method. This is the rationality of this technology and the technical effect it brings.

[0046] The internal standard method of the present invention has great application value and can be applied to many online measurements. Because in the process of online measurement, it is impossible to use the traditional internal standard method, that is, to add a quantitative internal standard element to the material to be measured. The traditional internal standard method requires knowing the weight of the internal standard element and the object to be measured at the same time, and the two need to be fully mixed. However, it is difficult to achieve these two requirements during online measurement. The method of the present invention avoids adding internal standard elements, but accurately measures a certain element in the object to be measured, which has the same effect as adding internal standard elements. For example, for the measurement of coal, it is currently more convenient to use X-ray fluorescence analysis XRF to measure elements such as Ca, Ti, and Fe. However, if you want to measure elements such as Na, Mg, Al, Si, C, and H in coal, it is very difficult to use XRF or LIBS. It requires very complicated sample preparation, and the coal needs to be ground and pressed into cakes. The measurement environment needs to be vacuumed and other processes. These process processes produce a long lag time, and the entire system is complex and has a high failure rate. Even if such a complex process is adopted, the LIBS measurement of the element content in coal is still affected by various factors. If the method of the present invention is adopted, the iron content in coal can be measured using XRF, set as C Fe , iron will be used as the internal standard element. The process of LIBS measurement is as follows: for example, a ns-level infrared pulse laser with a single pulse energy of tens of mJ is used to irradiate the coal sample, and plasma is generated at the irradiated point. The emission spectrum of the plasma is measured using a spectrometer. By selecting one or more spectrometers with different frequency bands, the spectral line area (also called spectral line intensity) of the emission spectrum of elements such as Fe, Na, Mg, Al, Si, C, and H can be measured, which are respectively expressed as S Fe , S Na , S Mg , S Al , S Si , S C , S H , assuming that the conversion factors of each element are 1, A Na , A Mg , A Al , A Si , A C , A H , it is difficult to actually measure the conversion factor, but it can be calculated as a parameter in data fitting. The content of Na, Mg, Al, Si, C, and H elements is From the above formula, we can see that by comparing the spectral line area of ​​each element to the spectral line surface value of iron, the influence of common factors affecting the spectral lines of each element can be eliminated, thereby improving the reliability of measurement. XRF and LIBS complement each other to achieve online measurement. Taking Na as an example, how to obtain the conversion factor of Na element is explained. A sample is used to measure using the method of the present invention to obtain C Fe, S Fe , S Na , and the Na content in the sample C Na It can be obtained through testing, so there is This formula can be used to calculate the conversion factor A of the Na element: Na ,In order to improve the accuracy, multiple samples can be calibrated and the conversion factors of each element can be finally obtained.

[0047] Commonly used XRF devices mainly include X-ray sources, X-ray detectors, X-ray energy spectrum acquisition modules, and computers. The measurement process is that the X-ray source emits X-rays, which are irradiated onto the sample, and produce characteristic X-rays of different energies with different elements in the sample. These rays are measured by the X-ray detector, and the detector output signal is converted into an energy spectrum by the energy spectrum acquisition module. The content of the element can be calculated based on the energy spectrum. Commonly used XRF quantitative analysis methods include basic parameter method, multiple regression method, and Compton ratio method. Taking the Compton ratio method as an example, if the sample contains Fe element, an energy peak will appear at the position of 6.4keV in the energy spectrum. The area of ​​the energy peak is calculated, and then a section of the Compton scattering area in the energy spectrum is selected for calculation. The ratio of the Fe energy peak to the Compton area area is linearly related to the Fe content. The content of iron element can be calculated based on this ratio.

[0048] From the calculation formula of the element, it can be seen that the conversion factor needs to be accurately set. In the above example, a simple constant is used as the conversion factor. In practical applications, the element calculation formula may be more complicated, and a conversion function needs to be defined: its independent variables are the characteristic spectral line area S0 of the internal standard element, the characteristic spectral line area S of the mth element to be measured, and the conversion function S m (m=1…n), there are n elements to be tested, and the dependent variable is the content C of the mth element to be tested m The ratio of the internal standard element content C0, the conversion function can be expressed as: C m / C0=f m (S0,S m ), m = 1…n. Each element to be measured has its own conversion function f m (), m = 1…n, they can be obtained by fitting the measured data of multiple sets of standard samples with known element contents. The fitting process is implemented by computer, and there are many fitting methods, such as least squares fitting, principal component analysis, ridge regression, neural network, etc. m () The simplest form can be f m (S0,S m )=A m ·S m / S0, where A mis a constant, i.e. the conversion factor mentioned above. It can also be other more complex formulas, which depends on the data obtained by measuring the standard sample. If the presence of the kth element affects the spectral line area of ​​the mth element, the conversion function can be expressed as: C m / C0=f m (S0,S m ,S k ), and even more spectral line areas of other elements need to be introduced as independent variables of the conversion function. Of course, the number of independent variables should not be too large, otherwise the stability of the conversion function will be affected.

[0049] Example 1

[0050] like Figure 1 As shown, a method for determining element content in this embodiment includes the following steps.

[0051] Step 101: using an X-ray fluorescence analysis device to measure the content of at least one preset internal standard element in a material to be tested.

[0052] Step 102: using a laser induced breakdown spectrometry analysis device to measure characteristic spectral lines of the preset internal standard element and the element to be measured in the material to be measured.

[0053] Step 103: Determine a conversion function between each element to be measured and the corresponding preset internal standard element with respect to the characteristic spectrum line and the content.

[0054] Step 104: Determine the content of each element to be measured according to a conversion function between a characteristic spectrum line and a content of each element to be measured and a corresponding preset internal standard element.

[0055] In this embodiment, one or more elements are selected whose characteristic X-ray energy is relatively high and which can be measured by XRF without vacuuming, and whose spectral lines measured by LIBS are not interfered by spectral lines of other elements, and the one or more elements are used as preset internal standard elements.

[0056] One or more elements in the material to be tested are selected as internal standard elements, and the best internal standard element (the internal standard element with the best correlation) is selected for each element to be tested, that is, the preset internal standard element.

[0057] Wherein, step 101 specifically includes: using XRF to measure the contents of k (k>0) preset internal standard elements in the material to be tested, respectively denoted as C 01 , C 02 , …, C 0k .

[0058] Step 102 specifically includes: using LIBS to measure the characteristic spectral lines of the preset internal standard element and the element to be measured in the object to be measured, and the areas (or spectral line intensities) of the characteristic spectral lines of the k preset internal standard elements are respectively recorded as S 01 , S 02 ,…,S 0k The areas (or spectral line intensities) of the characteristic spectral lines of the n elements to be measured are respectively denoted as S1, S2, ... n .

[0059] Wherein, step 103 specifically includes:

[0060] The conversion function C of the mth element to be measured m / C 0j =f m (S 0j ,S m ), m=1…n, j=1…k, a laser induced breakdown spectroscopy analysis device is used to collect multiple groups of sample data about the mth element to be measured; each group of sample data includes the area of ​​the characteristic spectrum line of the mth element to be measured, the area of ​​the characteristic spectrum line of the preset internal standard element corresponding to the mth element to be measured, and the content ratio C of the mth element to be measured and the corresponding preset internal standard element m / C 0j .

[0061] The multiple sets of sample data are sample data of multiple standard samples. The above multiple sets of data are used to fit the conversion function f m ().

[0062] The plurality of groups of sample data are fitted to obtain a conversion function between the characteristic spectrum line and the content of the mth element to be measured and the corresponding preset internal standard element.

[0063] The fitting method for fitting the multiple groups of sample data includes the least squares method.

[0064] The conversion function is represented by C m / C0=f m (S0,S m ), m = 1…n, where f m () is the conversion function. Each element to be measured has its own preset internal standard element, and each element to be measured has its own conversion function.

[0065] Using LIBS measurement data, the content C of the mth element to be measured can be calculated through the conversion function m The ratio of the internal standard element content C0 can be measured by XRF, and the content C0 of the mth element to be measured can be calculated. m .

[0066] Furthermore, the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element is expressed as:

[0067] C m / C 0j =A m ·(S m / S 0j ) 3 +B m ·(S m / S 0j ) 2 +D m ·S m / S 0j +E m ;

[0068] Among them, C m is the content of the mth element to be measured, C 0j is the content of the jth preset internal standard element, S m is the area of ​​the characteristic spectrum line of the mth element to be measured, S 0j is the characteristic spectral line area of ​​the jth preset internal standard element, A m , B m , D m and E m are all constants.

[0069] Using the conversion function established in advance, calculate the content C of the mth element to be measured m =f m (S 0j ,,S m )·C0,m=1…n,f m () is the conversion function of the mth element to be measured.

[0070] When the presence of certain elements in the material to be tested affects the generation of characteristic spectral lines of another element, the spectral line area of ​​the certain elements is introduced into the conversion function of the mth element to be tested, and the conversion function is C m / C 0j =f m (S 01 ,S 02 …S 0k ,S1,S2,S m …S n ), calibrating with multiple standard samples, fitting the formula and parameters of the conversion function by numerical analysis, and evaluating the fitting effect by the C of the multiple standard samples m / C 0j The difference between the calculated and actual values ​​has the smallest standard deviation.

[0071] The material to be tested is a mineral, more specifically a coal mine, and the preset internal standard element is Fe.

[0072] Example 2

[0073] This embodiment provides a system for determining element content. The system for determining element content applies the method for determining element content described in Embodiment 1. Figure 2 As shown, the element content determination system includes: a transmission belt 6, a computing device, an X-ray fluorescence analysis device 1 and a laser induced breakdown spectrometry analysis device 3, wherein the X-ray fluorescence analysis device 1 and the laser induced breakdown spectrometry analysis device 3 are arranged above the transmission belt 6, and the transmission belt 6 is used to transmit the material to be tested 5, and the X-ray fluorescence analysis device 1 and the laser induced breakdown spectrometry analysis device 3 are both connected to the computing device.

[0074] The X-ray fluorescence analysis device 1 is used to measure the content of at least one preset internal standard element in the material to be tested 5 on the transmission belt 6.

[0075] Figure 2 The X-rays represented by the first region 2 include the emitted X-ray beam, the X-ray beam reflected by the material to be tested 5 and the characteristic X-rays, and the second region 4 includes the emitted laser and the light emitted by the plasma.

[0076] The laser induced breakdown spectroscopy analysis device 3 includes a laser, a spectrometer and a lens group.

[0077] The laser induced breakdown spectroscopy analysis device 3 is used to measure the characteristic spectral lines of the preset internal standard element and the element to be measured in the material to be measured 5 on the transmission belt 6.

[0078] The calculation device is used to determine the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element; according to the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element, the content of each element to be measured is determined.

[0079] In this embodiment, the material 5 to be tested is transported by a conveyor belt 6 to the XRF measuring device and the LIBS measuring device for direct measurement, without the need for vacuuming, grinding the material 5 to be tested into powder, or pressing the material 5 to be tested into a cake shape.

[0080] The X-ray fluorescence analysis device 1 and the laser induced breakdown spectroscopy analysis device 3 include two configuration modes.

[0081] Furthermore, the X-ray fluorescence analysis device 1 is used to measure in real time the content of at least one preset internal standard element in the material to be tested 5 on the transmission belt 6. The laser induced breakdown spectrometry analysis device 3 is used to measure in real time the characteristic spectral lines of the preset internal standard element and the element to be tested in the material to be tested 5 on the transmission belt 6. The calculation device is used to determine in real time the conversion function between the characteristic spectral line and the content of each element to be tested and the corresponding preset internal standard element; the content of each element to be tested is determined according to the conversion function between the characteristic spectral line and the content of each element to be tested and the corresponding preset internal standard element. When the transmission belt 6 is running, the calculation device can determine in real time the content of each element to be tested in the material to be tested 5 within the irradiation range, thereby improving the timeliness of the determination of the element content.

[0082] The first setting method is as follows Figure 2 As shown, the X-ray fluorescence analysis device 1 and the laser induced breakdown spectrometry analysis device 3 are sequentially arranged above the conveying belt 6 along the conveying direction of the conveying belt 6. The irradiation points of the XRF device and the LIBS device on the sample are on the same straight line parallel to the running direction of the conveyor belt.

[0083] When the transmission belt 6 is running, the computing device is used to delay the first measurement data transmitted by the X-ray fluorescence analysis device 1, so that the material 5 to be tested corresponding to the first measurement data after delay processing and the second measurement data transmitted by the laser induced breakdown spectrometry analysis device 3 is the material 5 to be tested at the same position on the transmission belt 6; the first measurement data is the content of at least one preset internal standard element, and the second measurement data is the characteristic spectrum of the preset internal standard element and the element to be tested. When the first setting is adopted, the area irradiated by the laser beam is included outside the area irradiated by the X-ray beam, and the time of the same sample position measured by LIBS is lagging behind that of XRF, which needs to be delayed in actual applications.

[0084] The second setting method is as follows Figure 3 As shown, the X-ray fluorescence analyzer 1 and the laser induced breakdown spectrometry analyzer 3 are arranged horizontally above the transmission belt 6, and the horizontal direction is perpendicular to the transmission direction of the transmission belt 6; the irradiation area of ​​the laser induced breakdown spectrometry analyzer 3 is included in the irradiation area of ​​the X-ray fluorescence analyzer 1. The irradiation points of the XRF device and the LIBS device on the sample overlap at the same time (there is no time difference), that is, the irradiation point of the LIBS device on the sample is within the irradiation area of ​​the XRF device.

[0085] The element content determination system described in this embodiment further includes an online moisture measurement device, which is connected to the computing device and is used to collect the moisture of the material to be measured on the transmission belt.

[0086] The calculation device is used for when the element to be measured is hydrogen, the content of hydrogen is the content after deducting the content of hydrogen in the water.

[0087] If only XRF is used to measure the elements such as Na, Mg, Al, Si, C, etc. in the mineral, it is necessary to consider the absorption of the characteristic X-rays by the air, and it is necessary to evacuate or fill with helium. In this way, during the measurement process, a sealed space must be designed, and a complex loading and unloading mechanism must be designed, and a cleaning mechanism must be set up to ensure the sealing. Such a system is very complicated, the real-time performance is reduced, the cost is increased, the reliability is reduced, and the direct measurement of continuous materials cannot be performed. The method of the present invention can be used to measure the Fe element in the mineral as an internal standard element by XRF. The characteristic X-ray energy of the Fe element is relatively high. XRF can directly measure the Fe element content of the mineral on the belt. Of course, other elements that are easy to accurately measure can also be selected as internal standard elements. LIBS can also directly measure the characteristic spectral lines of various elements of the mineral on the belt. Using the internal standard method, other element components can be more accurately measured to achieve the effect of 1+1>2. In this way, online element analysis can be performed, and the system is non-contact measurement, and its reliability and real-time performance are greatly enhanced.

[0088] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for determining element content, characterized in that: The method comprises: Using an X-ray fluorescence analyzer to measure the content of at least one preset internal standard element in the material to be tested; Using a laser induced breakdown spectroscopy analysis device to measure the characteristic spectral lines of the preset internal standard element and the element to be measured in the material to be measured; Determine the conversion function between the characteristic spectrum line and the content of each element to be measured and the corresponding preset internal standard element; Determine the content of each element to be measured according to the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element; each element to be measured has its own preset internal standard element, and each element to be measured has its own conversion function; The conversion function between the characteristic spectrum and content of each element to be measured and the corresponding preset internal standard element is expressed as: C m / C 0j =A m ·(S m / S 0j ) 3 +B m ·(S m / S 0j ) 2 +D m ·S m / S 0j +E m ; Among them, C m is the content of the mth element to be measured, C 0j is the content of the jth preset internal standard element, S m is the area of ​​the characteristic spectrum line of the mth element to be measured, S 0j is the characteristic spectral line area of ​​the jth preset internal standard element, A m , B m , D m and E m are all constants.

2. The method for determining element content according to claim 1, characterized in that: Determine the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element, specifically including: A laser induced breakdown spectroscopy analysis device is used to collect multiple groups of sample data about the mth element to be measured; each group of sample data includes the area of ​​a characteristic spectrum line of the mth element to be measured, the area of ​​a characteristic spectrum line of a preset internal standard element corresponding to the mth element to be measured, and the ratio of the content of the mth element to be measured to the corresponding preset internal standard element; The plurality of groups of sample data are fitted to obtain a conversion function between the characteristic spectrum line and the content of the mth element to be measured and the corresponding preset internal standard element.

3. The method for determining element content according to claim 2, characterized in that: Fitting the multiple groups of sample data to obtain a conversion function between the mth element to be measured and the corresponding preset internal standard element with respect to the characteristic spectrum line and content specifically includes: The plurality of groups of sample data are fitted by least square fitting to obtain a conversion function between the mth element to be measured and the corresponding preset internal standard element with respect to the characteristic spectrum line and the content.

4. The method for determining element content according to claim 1, characterized in that: The material to be tested is a mineral, and the preset internal standard element is Fe.

5. A system for determining element content, characterized in that: The element content determination system applies the element content determination method according to any one of claims 1 to 4, and the element content determination system comprises: a transmission belt, a computing device, an X-ray fluorescence analysis device and a laser induced breakdown spectrometry analysis device, wherein the X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device are arranged above the transmission belt, the transmission belt is used to transmit the material to be tested, and the X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device are both connected to the computing device; The X-ray fluorescence analysis device is used to measure the content of at least one preset internal standard element in the material to be tested on the transmission belt; The laser induced breakdown spectroscopy analysis device is used to measure the characteristic spectral lines of the preset internal standard element and the element to be measured in the material to be measured on the transmission belt; The calculation device is used to determine the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element; according to the conversion function between the characteristic spectrum and the content of each element to be measured and the corresponding preset internal standard element, the content of each element to be measured is determined.

6. The element content determination system according to claim 5, characterized in that: The X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device are sequentially arranged above the transmission belt along the transmission direction of the transmission belt; When the transmission belt is running, the computing device is used to delay the first measurement data transmitted by the X-ray fluorescence analysis device so that the material to be tested corresponding to the first measurement data after the delay processing and the second measurement data transmitted by the laser induced breakdown spectrometry analysis device is the material to be tested at the same position on the transmission belt; the first measurement data is the content of at least one preset internal standard element, and the second measurement data is the characteristic spectral lines of the preset internal standard element and the element to be tested.

7. The element content determination system according to claim 5, characterized in that: The X-ray fluorescence analysis device and the laser induced breakdown spectrometry analysis device are arranged laterally above the transmission belt, and the transverse direction is a direction perpendicular to the transmission direction of the transmission belt; the irradiation area of ​​the laser induced breakdown spectrometry analysis device is contained in the irradiation area of ​​the X-ray fluorescence analysis device.

8. The element content determination system according to claim 5, characterized in that: It also includes an online moisture measuring device, which is connected to the computing device and is used to collect the moisture of the material to be measured on the transmission belt; The calculation device is used for when the element to be measured is hydrogen, the content of hydrogen is the content after deducting the content of hydrogen in the water.

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