Method and detection device for determining chemical composition of used refractory material

Abstract

The present invention provides a method for determining the chemical composition (CC) of a used refractory material sample (M) to allow sorting and recovery of the refractory material sample (M) to achieve the concept of low or zero waste. The method is characterized by: a breakdown step during which a pulsed laser beam (L) is irradiated by a laser source (2) onto a detection portion (E) of a used refractory material sample (M), thereby forming a plasma in said detection portion (E); a recording step during which the detection unit (3) records the spectral emission (S) of the detection portion (E); and an evaluation step during which the evaluation unit (4) determines the chemical composition in the detection fraction (E) using the spectral lines of the recorded spectral emissions (S), the carbon content in the detection fraction (E) being determined using spectral lines at a wavelength of about 193 nm, and determining the chemical composition (CC) of the used refractory material sample (M) by using the chemical composition in the detection section (E).

Description

Technical Field

[0001] The present disclosure relates to a method and a detection device for determining the chemical composition of a spent refractory material sample. Background Art

[0002] Refractory products, such as bricks and tiles, may contain carbon, for example, when using magnesium-carbon (MgO-C), aluminum-magnesium-carbon (Al2O3-MgO-C; AMC) or dolomite-carbon (MgO-CaO-C) materials. Refractory products may also be carbon-free, such as for products based on fired magnesia or high-alumina materials. The specific choice of raw materials for the refractory product may depend on its application and location within the metallurgical vessel lining.

[0003] Used refractory products or their components can be recycled. To this end, different types of refractory bricks, tiles, etc., originally installed in different lining areas of various metallurgical vessels and having different physical and chemical compositions, are removed and often stored together. In order to allow the used refractory products or their components to be reintegrated into refractory production while ensuring the high quality of the resulting product for demanding applications, effective sorting and separation steps based on different characteristics are required. In this regard, the chemical composition of the material is considered the primary characteristic, while density, thermal conductivity, color, etc. are considered secondary characteristics.

[0004] X-ray based methods are generally reliable for contactless determination of the chemical composition of samples. However, a major disadvantage of X-ray based methods is the inability to reliably detect light elements such as Al, Mg, Si, Ca or C within acceptable measurement times (<1 s). Furthermore, due to the involvement of ionizing radiation, X-ray based methods generally require strict regulations in terms of work safety and radiation protection. In addition, for coarse textured materials, multiple measurements must be performed on each sample and averaged to obtain satisfactory results. Furthermore, X-ray fluorescence based methods may be susceptible to surface contamination due to the small interaction volume of the sample, while for X-ray transmission based methods, the sample must have a sufficiently small thickness.

[0005] Due to the limitations of known methods, sorting is still typically performed manually by human operators, where the quality of the sorting depends entirely on the operator's experience. Consequently, throughput and ultimately the quality of the sorting are often low, as only a small number of individual sorting categories can be managed this way. Furthermore, manual sorting is limited to larger fragments, i.e., intact bricks or fragments with a particle size greater than 80 mm, which typically only account for approximately 40% of the total available used material. Furthermore, some refractory product types cannot be manually sorted due to insufficient visual or morphological differentiation between them.

[0006] Used refractory products may also be contaminated with slag, metal (e.g. iron) or other undesirable materials. Therefore, it may be advantageous to pulverize the used refractory material and pre-sort the pulverized refractory material (e.g., by magnetic separation of ferrous components) prior to the main sorting step. Summary of the Invention

[0007] The object of the present invention is to provide a method and a detection device for determining the chemical composition of used refractory materials in order to achieve sorting and recycling and to achieve a low waste or zero waste concept.

[0008] This is achieved by irradiating a pulsed laser beam by a laser source onto a test portion of the used refractory material sample during the breakdown step to form a plasma in the test portion, wherein a spectral emission of the test portion is recorded by a detection unit during the recording step, wherein a chemical composition in the test portion is determined by the evaluation unit using spectral lines of the recorded spectral emission during the evaluation step, wherein a spectral line having a wavelength of approximately 193 nm is used to determine the carbon content in the test portion during the evaluation step, and the chemical composition of the used refractory material sample is determined by using the chemical composition in the test portion. In the context of the present disclosure, the term "sample" refers to a single, independent piece or fragment of a used refractory product.

[0009] Furthermore, the above-mentioned object is achieved by a detection apparatus, comprising a laser source configured to irradiate a pulsed laser beam onto a detection portion of a refractory material sample during a breakdown step to form plasma in the detection portion. The detection apparatus further comprises a detection unit configured to record spectral emissions from the detection portion during a recording step, and an evaluation unit configured to determine a chemical composition in the detection portion using the recorded spectral emissions during the evaluation step, while simultaneously determining a carbon content in the detection portion using a spectral line having a wavelength of approximately 193 nm during the evaluation step, wherein the chemical composition of the used refractory material sample is determined from the chemical composition in the detection portion.

[0010] During the testing step, when determining the chemical composition of the used refractory material sample in the test portion, the carbon content is determined by using at least a spectral line having a wavelength of about 193 nm. Thus, determining the carbon content is at least a part of determining the chemical composition. In addition, by studying the spectral lines at wavelengths characteristic of the other elements, it is possible to determine other elements present in the test portion, and thus, determining the contents of those other elements may also be part of determining the chemical composition.

[0011] The method and detection device disclosed herein can also be used to determine the carbon content of a used refractory material sample. Thus, during a breakdown step, a pulsed laser beam is irradiated by a laser source onto a detection portion of the used refractory material sample to form a plasma in the detection portion. During a recording step, a spectral emission of the detection portion is recorded by a detection unit. During an evaluation step, a spectral line having a wavelength of approximately 193 nm in the recorded spectral emission is used by the evaluation unit to determine the carbon content in the detection portion. The carbon content of the used refractory material sample is determined by using the carbon content in the detection portion.

[0012] "Approximately 193 nm" means that 193.0 nm can be used, but wavelengths with minimal deviations can also be used depending on the measurement parameters (such as the composition and pressure of the surrounding gas, temperature, etc.). For example, a wavelength of 193.09 nm can be used because this is the spectral line of carbon under vacuum conditions. Preferably, the integral is formed within the 193 nm range, for example, from 192.8 nm to 193.2 nm.

[0013] The detection portion is located on the used refractory material sample to be studied. When the pulsed laser beam irradiates the detection portion, a plasma that locally ablates the material is formed by electronic excitation of atoms and ions in the detection portion. The detection portion is instantaneously heated to a temperature exceeding 10,000K, and the material evaporates from the surface of the sample to a depth in the range of about 100μm to several millimeters. The detection portion may be conical. A pulsed laser beam with a pulse duration in the nanosecond range and a pulse energy of about 100μJ to about 100mJ can be used, wherein the diameter of the focal area is preferably less than 1mm. The size of the used refractory material sample to be tested is preferably larger than the focal area. The pulsed laser beam can generate 1Gw / cm 2 The irradiance is within a certain range. Nd:YAG lasers can be used as laser sources. Plasma formation using a (focused) pulsed laser beam, followed by optical emission spectroscopy of the induced plasma, is commonly referred to as "laser-induced breakdown spectroscopy" (LIBS), or sometimes "laser-induced plasma spectroscopy" (LIPS). LIBS can achieve a lateral spatial resolution of better than 0.5 mm.

[0014] Since previous methods for determining the chemical composition of used refractory materials were only applicable to sufficiently large samples with a characteristic size greater than 80 mm, smaller fragments could not be recycled and had to be landfilled or downcycled. By using LIBS, single particle analysis can be performed and the chemical composition of small fragments (i.e., with a characteristic size equal to or less than 80 mm) can also be determined, allowing these fragments to be recycled rather than landfilled or downcycled. In principle, the minimum particle size of used refractory samples that can be analyzed by LIBS is limited by the size of the laser focal spot, so particle sizes from 2 mm to 200 mm and above can be analyzed. Typically, samples smaller than the laser focal spot can also be analyzed. According to the method described in this article, it is possible to analyze the chemical composition of used refractory materials directly in the production line under on-site and real-time conditions. This application scenario is also called online analysis. Using LIBS, there is no need for complex pretreatment of the sample and only trace amounts of material are ablated.

[0015] According to the method described herein, carbon is detected using a spectral line at a wavelength of approximately 193 nm to determine the carbon content in the test portion. Conventionally, carbon can be detected from spectral emissions by processing the spectral line at a wavelength of 247.856 nm. However, this spectral line has only low sensitivity and, more importantly, is subject to interference from the iron spectral line at a wavelength of 247.857 nm. Since typical spectrometers only offer a spectral resolution of 0.02-0.3 nm, it is impossible to distinguish between wavelengths of 247.856 nm and 247.857 nm. For these reasons, the 247.856 nm spectral line is only suitable for detecting high concentrations of carbon and only when the material contains no iron or a negligible iron content. Since used refractory materials may contain significant amounts of carbon, ranging in the range of several mass %, and may also contain iron, the 247.856 nm spectral line cannot be used alone. Nevertheless, when carbon content is primarily assessed using a signal at a wavelength of approximately 193 nm, the spectral line at 247.856 nm can still be used as an auxiliary input.

[0016] Preferably, the carbon content in the detection portion is determined by using an auxiliary spectral line of an auxiliary wavelength in the recorded spectral emission. This is particularly important if oxygen is present in the detection portion, as both carbon and oxygen have a spectral line at approximately 193 nm. Therefore, the carbon content in the detection portion can still be determined by using an auxiliary spectral line of an auxiliary wavelength in the recorded spectral emission, preferably an auxiliary spectral line of oxygen (for example, a spectral line with a wavelength of approximately 777 nm). "About 777 nm" means that 777.0 nm can be used, and wavelengths with minimal deviation can also be used depending on the measurement parameters (composition and pressure of the surrounding gas, temperature, etc.). Preferably, the integral of the measured signal is calculated within the 777 nm range (for example, 776 nm to 778 nm). Oxygen contained in the air surrounding the detection portion also absorbs radiation at approximately 193 nm, and its content can be determined by using the spectral line with a wavelength of approximately 777 nm, and this information can be used to reduce the influence of oxygen at a wavelength of 193 nm by the following correction scheme. The oxygen content determined by the spectral line at a wavelength of 777 nm can be used to calibrate the spectral line obtained at about 193 nm to obtain the carbon content in the detection portion. Therefore, there is no need to use a protective inert gas atmosphere (e.g., argon or nitrogen) and / or a closed housing to prevent the influence of oxygen.

[0017] In summary, at a wavelength of approximately 193 nm, a combined value for the carbon and oxygen contents in the test portion can be determined, for example, by integrating the spectral line from 192.8 nm to 193.2 nm. An auxiliary spectral line at a wavelength of approximately 777 nm can be used to determine the value for the oxygen content in the test portion, for example, by integrating from 776 nm to 778 nm. This auxiliary spectral line can then be used to correct the spectral line at approximately 193 nm to obtain the carbon content in the test portion, for example, by subtracting the oxygen content value from the combined value for the carbon and oxygen contents.

[0018] During the detection step, when determining the chemical composition of the used refractory sample in the detection portion, not only the carbon content can be determined (by using the spectral line at a wavelength of about 193 nm as described above), but also other elements present in the detection portion can be determined by studying the spectral lines at wavelengths characteristic for the other elements, such as, for example, Al (309.3 nm), Mg (279.6 nm), Si (390.6 nm), Ca (396.8 nm). For this purpose, wavelengths in the spectral range of 175–1000 nm can be recorded. Here, integration within the expected wavelength range can also be used.

[0019] Preferably, during the preselection step, the detection moieties are designated by an imaging unit. Thus, the detection apparatus may include an imaging unit for preselecting the detection moieties. Preselection may be based on one or more of the following characteristics: size, volume, surface topography, spectrum (with lower spectral resolution compared to LIBS), etc.

[0020] The imaging unit used for the preselection step or another imaging unit can be used for a pre-analysis step, wherein the pre-analysis can be performed taking into account one or more of the following characteristics of the sample: size, volume, surface morphology, spectrum (with lower spectral resolution compared to LIBS). The results from the pre-analysis step may already allow the chemical composition of the used refractory material sample to be determined and / or can be used to support the analysis by LIBS, for example, if the sample shows a very different chemical composition, such as MgO-C mixed with refractory clay (chamotte).

[0021] The distinction between the optional preselection step and the optional preanalysis step (both of which use one (and possibly the same) imaging unit) is as follows: the preselection step can be used to analyze the used refractory material sample to select a suitable detection portion for LIBS measurement in a subsequent step, while the preanalysis step analyzes the used refractory material sample to determine its characteristics. These characteristics can help determine the chemical composition, or they can be used to support the LIBS analysis. These characteristics can also be used to classify the used refractory material sample, as further described below.

[0022] Color and / or hyperspectral cameras can be used as imaging units for the preselection and / or preanalysis steps. Hyperspectral cameras allow the use of hyperspectral imaging (HSI) methods. Since HSI offers only low spectral and lateral resolution, this method alone may not be sufficient to reliably determine the chemical composition of spent refractory samples. However, it can be used to support LIBS measurements during the preanalysis step. On the other hand, HSI is very suitable for preselection, i.e., for determining the most suitable inspection section for the breakdown step (i.e., the localized plasma generation step of LIBS).

[0023] During the preselection step, for example, detection portions having a specific optical surface characteristic (eg a largest optically homogeneous portion) can be determined.The optical characteristic may be an indicator for a specific chemical composition.

[0024] 3D cameras enable 3D object recognition, where, for example, the volume, morphology, and shape of a spent refractory sample can be determined. Using this information, suitable inspection sections can be determined during a preselection step, and / or a pre-analysis step can be performed to obtain characteristics of the spent refractory sample, such as the characteristics of the disassembled and pulverized material (e.g., geometric aspect ratio and / or shape factor). The shape of the fragments can, in turn, provide initial clues to various characteristics of the spent refractory material and support the determination of chemical composition and material classification by LIBS.

[0025] The detection portion may be pre-treated by a cleaning step, preferably a laser cleaning step performed by the laser source and / or the second laser source irradiating a cleaning laser beam onto the detection portion prior to irradiation with the pulsed laser beam for LIBS measurement. Thus, the laser source and / or the second laser source may be configured to irradiate a cleaning laser beam onto the detection portion prior to irradiation with the pulsed laser beam. The cleaning laser beam may have a repetition rate in the range of 100 kHz to 200 kHz, wherein the repetition rate of the breakdown laser may be in the range of 10 Hz to 100 Hz. Providing a cleaning step may help remove surface contamination present in the detection portion. Of course, the cleaning step does not have to be limited to the detection portion, but may also cover only a portion of the detection portion or a larger area of ​​the sample.

[0026] The breakdown step, the recording step, and the evaluation step can be performed for a plurality of detection portions of the used refractory material sample, wherein the chemical composition of the used refractory material sample is determined from the results of the evaluation step for the plurality of detection portions. To this end, the laser source can be configured to irradiate a pulsed laser beam onto the plurality of detection portions of the refractory material sample, thereby forming a plasma in the plurality of detection portions, wherein the detection unit can be configured to record spectral emissions from the plurality of detection portions, and wherein the evaluation unit can be configured to determine the chemical composition in the plurality of detection portions, wherein the detection apparatus further includes a merging unit configured to determine the chemical composition of the used refractory material sample from the determined chemical compositions in the plurality of detection portions. This can be accomplished by interpolation or averaging, for example, by the merging unit, which can be part of the evaluation unit.

[0027] Therefore, LIBS measurements can be used to measure multiple test portions of a sample of used refractory material to determine the chemical composition within these test portions, and thereby determine the chemical composition of the sample of used refractory material. This allows for a more representative determination of the chemical composition of the used refractory material of the sample, even if the chemical composition is not uniformly distributed throughout the sample. In this regard, performing a preselection step for determining multiple test portions can improve the speed and quality of the analytical method.

[0028] The refractory material sorting system may include a detection device as described herein, wherein the detection device is configured to determine the chemical composition of a plurality of refractory material samples, and further includes a sorting unit configured to sort the plurality of used refractory material samples based on their chemical composition during the sorting step. The sorting step based on chemical composition can be performed by using a decision tree or artificial intelligence (AI) and / or machine learning (ML) algorithm. Carbon content and the content of other elements (e.g., Al, Mg, Si, Ca, etc.) or different proportions therebetween can be used as criteria for sorting decisions. If a pre-analysis step is provided, the sorting step can also be based on the results of the pre-analysis step.

[0029] Preferably, the refractory material sorting system may include a transport unit, such as a conveyor belt, for transporting a plurality of used refractory material samples. The refractory material sorting system may further include a feeding unit for feeding the used refractory material samples into the transport unit, wherein the feeding unit may further include a feeding hopper and / or a vibrating trough. The refractory material sorting system may further include a control unit connected to the detection device and controlling the sorting unit based on the results obtained from the evaluation unit. If a transport unit is used, the control unit may also control the transport unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figures 1 to 5b An exemplary and non-limiting schematic diagram of a preferred embodiment of the present invention is shown, wherein:

[0031] Figure 1 A detection portion of an exemplary detection device for detecting a refractory material sample is shown.

[0032] Figure 2 shows the detection of multiple detection parts,

[0033] Figure 3 An exemplary sorting system is shown,

[0034] Figure 4a 、 Figure 4b A portion of an exemplary spectral emission is shown,

[0035] Figure 5a 、 Figure 5b An exemplary processing of the spectral emission is shown. DETAILED DESCRIPTION

[0036] Figure 1An exemplary detection device 1 for determining the chemical composition CC of a used refractory material sample M is shown. To this end, the used refractory material sample M having an at least partially unknown chemical composition CC is placed at a target area T. The detection device 1 includes a laser source 2 configured to irradiate a pulsed breakdown laser beam L onto a detection portion E of the refractory material sample M placed in the target area T during a breakdown step, thereby forming a plasma in the detection portion E. Preferably, the detection portion E is specified by a preselection step. The detection device 1 further includes a detection unit 3 configured to record a spectral emission S from the detection portion E during a recording step. In addition, the detection device 1 includes an evaluation unit 4 configured to determine the chemical composition in the detection portion E using the spectral emission S recorded during the recording step, wherein the carbon content in the detection portion E is determined by using a spectral line with a wavelength of approximately 193 nm (which spectral line overlaps with the oxygen spectral line). The carbon content in the detection portion E can then be corrected by using an auxiliary spectral line at another wavelength of the spectral emission, for example, an auxiliary spectral line of oxygen (preferably with a wavelength of 777 nm). Furthermore, by studying the characteristic spectral lines of the recorded spectral emission S, the chemical composition of the detection portion E with respect to one or more elements among Al, Mg, Si, Ca can be determined.

[0037] The chemical composition CC of the used refractory material sample M can be determined from the chemical composition of the test portion E. If the chemical composition CC of the used refractory material sample M is uniform, then determining the chemical composition of the test portion E may be sufficient to infer the chemical composition CC of the used refractory material sample M.

[0038] Figure 1 Also shown is an optional imaging unit 5, preferably a color and / or hyperspectral camera, which can record an image I of the used refractory material sample M, which can be used to preselect the test portion E in the preselection step and / or to perform a pre-analysis step. By preselecting a suitable test portion E in the preselection step, the determination of the chemical composition CC of the used refractory material sample M from the chemical composition of the test portion E can be optimized.

[0039] A control unit 11 may be provided to control the detection device 1 (and thereby the laser source 2, the detection unit 3 and the evaluation unit 4) - Figure 1 and Figure 2 Not shown, but in Figure 3 Shown in.

[0040] Preferably, as in Figure 2As shown in , a breakdown step, a recording step and an evaluation step are performed on a plurality of detection portions E, E', E" of a used refractory material sample M. Each detection portion E, E', E" is irradiated by a pulsed breakdown laser beam L, L', L" and generates spectral emissions S, S', S", which are recorded by a detection unit 3. The chemical composition CC of the used refractory material sample M can then be determined (for example, by interpolation or averaging) from the chemical composition obtained in the evaluation step at the detection portions E, E', E", even if the chemical compositions of the individual detection portions E, E' and E" within the used refractory material sample M are different from each other. This can be done by a merging unit 41, for example, as part of the evaluation unit 4.

[0041] Before irradiating the penetrating laser beam L, the detection part E (or the detection parts E, E', E") may also be pretreated during a cleaning step, preferably during a laser cleaning step (not shown in the figure) performed by a laser source 2 or a second laser source, which irradiates a high-frequency pulse-modulated cleaning laser beam to the detection part E (or the detection parts E, E', E") .

[0042] Figure 3 An exemplary sorting system 10 is shown, which includes a detection device 1 according to the present disclosure, herein Figure 1 As an example, the detection device 1 shown in FIG. Figure 3 As shown in FIG, a plurality of used refractory material samples M are tested. As an example, the refractory material sorting system 10 further includes a transport unit 7, which is a conveyor belt in this case, for transporting the plurality of used refractory material samples M to a target area T. Figure 3 As shown, the used refractory material sample M can be fed to the transport unit 7 through the hopper 8. The positioning of the detection device 1 enables the laser source 2 to irradiate the pulsed breakdown laser beam L onto the detection portion E of the used refractory material sample M located in the target area T. To this end, the used refractory material sample M is transported to the target area T by the transport unit 7.

[0043] As described above, during the breakdown step, the breakdown laser beam L forms plasma in the detection portion E, the spectral emission S from the detection portion E is recorded by the detection unit 3 during the recording step, and during the evaluation step, the chemical composition in the detection portion E is determined by the evaluation unit 4 using the spectral emission S recorded during the recording step.

[0044] Based on its chemical composition CC, the used refractory material sample M can be classified into different material classes. The material class can be determined not only by using high-resolution spectral signatures based on the LIBS measurement position, but also based on results from preselection steps, such as surface topography, sample volume, and large-area surface spectral signatures at low spectral resolution (e.g., by HSI).

[0045] During the sorting step, the sorting unit 6 sorts the spent refractory material samples M, for example, by moving them into containers 9 divided into the corresponding material categories. This can be done by an ejection unit (ejection area A) located after the target area T (by Figure 3 The ejection unit may include a robotic arm and / or a gas nozzle for moving the spent refractory material sample M into the container 9.

[0046] A control unit 11 may be provided to control the detection device 1 (and thus the laser source 2 , the detection unit 3 and the evaluation unit 4 ), but also the transport unit 7 .

[0047] During the puncturing step and / or the detection step, the movement of the transport unit 7 can be stopped or slowed down by the control unit 11. It is also possible that the movement of the transport unit 7 is not stopped or slowed down, in which case the control unit 11 will handle the movement of the detection portion E when controlling the puncturing step and / or the detection step, for example by ensuring that the pulsed puncturing laser beam L follows the detection portion E.

[0048] Figure 4a and Figure 4b A comparison of two exemplary spectral emissions S of two different detection portions E of two different used refractory material samples M is shown, wherein Figure 4a shows the spectral emission between 190 nm and 360 nm, Figure 4b The spectral emission is shown for wavelengths between 250 nm and 880 nm. For the two samples M, the following steps can be performed simultaneously or sequentially.

[0049] For each sample M, during the breakdown step, a pulsed laser beam L is irradiated by the laser source 2 onto the corresponding detection portion E, thereby forming a plasma in said detection portion E. During the respective recording step, the spectral emission S of said detection portion E is recorded by the detection unit 3 . Figure 4a 、 Figure 4b The curves showing the corresponding spectral emission lines are of different thicknesses, making it easier to distinguish the spectral emission S.

[0050] The finer spectral emission lines originate from the first detection portion E of the first sample M, which is a MgO—C material containing 1% by mass of carbon. The thicker spectral emission lines originate from the second detection portion E of the second sample M, which is a MgO material containing <0.1% by mass of carbon.

[0051] In particular, Figure 4a The carbon spectral line at about 193 nm is shown in Figure 4b The oxygen spectral line at about 777 nm is shown in FIG. Figure 4a The figure shows an enlarged view of two spectral lines near 193 nm. Figure 4b The enlarged image of two spectral lines near 777nm is shown in Figure 2. Figure 4a and Figure 4b Various spectral lines of Na, Mg and Ca can also be seen.

[0052] for Figure 4b The two samples M in FIG. 1 and FIG. 2 both show a clearly visible spectral line at 248 nm. However, since the spectral line may originate from iron or carbon, this spectral line cannot be used to determine the carbon content of the corresponding detection portion E.

[0053] The carbon content can now be determined by using the spectral lines at a wavelength of approximately 193 nm. This can be performed by integrating the spectral lines near a wavelength of 193 nm, thereby determining the combined value va of the carbon and oxygen contents in the corresponding detection portion E. By integrating the auxiliary spectral lines at wavelengths of 776 nm to 778 nm, the value vO of the oxygen content in the corresponding detection portion E can be determined. The determined oxygen content value vO can then be used to correct the combined value va to obtain the value of the carbon content in the corresponding detection portion E, for example, by adding a correction value vx proportional to the oxygen content vO to the combined value va of the carbon and oxygen contents or subtracting the correction value vx from the combined value va. By doing so, the carbon content in the corresponding detection portion E can be determined, and further the chemical composition CC of the corresponding applied refractory material sample M can be determined.

[0054] Figure 5a An exemplary processing of the spectral emission S by the evaluation unit 4 is shown. In a first step s1, a combined value va for the carbon and oxygen content in the respective detection portion E is determined, for example, by integrating spectral lines around a wavelength of 193 nm. In a second step s2, a value vO for the oxygen content in the respective detection portion E is determined, for example, by integrating auxiliary spectral lines with wavelengths between 776 nm and 778 nm. The first step s1 and the second step s2 can be performed in any order or sequentially.

[0055] In a third step s3, the oxygen content value vO is used to correct the integrated value va to obtain the value of the carbon content in the detection portion E, for example by subtracting the correction value vx derived from the determined oxygen content vO. Thus, the chemical composition of the corresponding detection portion E with respect to the carbon content can be determined.

[0056] Similarly, the content of Na, Mg and Ca can be determined by using the spectral lines at the corresponding wavelengths, for example, by integrating the spectral lines around the corresponding wavelengths. This can be used to further determine the chemical composition in the detection portion E.

[0057] The chemical composition CC of the used refractory material sample M can then be inferred from the chemical composition in the test portion E, which is also Figure 5a is performed during the third step s3.

[0058] Furthermore, the quotient q can be calculated by dividing the combined carbon and oxygen value va (determined at approximately 193 nm) by the oxygen content value vO (determined at approximately 777 nm), and the quotient q can then be used to determine the chemical composition in the corresponding detection portion E, which in turn can be used to determine the chemical composition CC of the refractory material sample M.

[0059] Figure 5b FIG. 4 shows an exemplary processing of the spectral emission S by the evaluation unit 4. Figure 5a Similarly, in the first step s1, the integrated value va of the carbon and oxygen contents in the detection portion E is also determined.

[0060] Likewise with Figure 5a Similarly, in the second step s2 , the value vO of the oxygen content in the detection portion E is determined. The first step s1 and the second step s2 can likewise be performed in any order or sequentially.

[0061] Now, in a third step s3, the integrated value va is divided by the oxygen content value vO of the detection portion E to calculate a quotient q.

[0062] In a fourth step s4, the quotient q is compared with one or more reference quotients qr of known materials with known chemical compositions, thereby determining the chemical composition of the test portion E and further determining the chemical composition CC of the refractory material sample M.

[0063] Figure 5a and Figure 5b The steps shown in can be performed for each detection part E.

[0064] By processing the two spectral emissions S from Figure 4 , a quotient q can be calculated for each detection portion E. Thus, it can be determined that the carbon content of the first detection portion is 10 times that of the second detection portion. Therefore, if a reference quotient qr for a reference material having a reference carbon content is known, the carbon content of any detection portion E can be determined by comparing the corresponding quotient q for that detection portion E with the reference quotient qr. Thus, a quotient q of approximately 2 might indicate that the material of the detection portion E is MgO-C, which is assigned a reference quotient qr of 2, whereas a quotient q of approximately 0.2 might indicate that the material of the detection portion E is MgO, which is assigned a reference quotient qr of 0.2. Of course, the range of reference quotient qr can generally be divided into MgO-C (e.g., ranging from 0.5 to 4) or MgO (e.g., ranging from 0 to 0.5). This approach can also be applied to other materials. Determining the quotient q can also be used to determine whether one of two (or more) materials with different carbon contents is present in any detection portion E. For example, if it is to be determined whether a test portion E contains MgO or MgO-C, the above-mentioned quotient q can be determined for said test portion E and then compared with one or two reference quotients qr divided into MgO and / or MgO-C to determine which material is present in the test portion E. The chemical composition CC of the refractory material sample M can be determined from the chemical composition determined in the corresponding test portion E.

[0065] The above analysis is only described by taking two detection portions E in two different refractory material samples M as an example to illustrate the different chemical compositions of these detection portions E. Of course, only one or more than two detection portions E in one or more refractory material samples M may also be analyzed simultaneously or sequentially.

[0066] The above analysis can also be applied to a plurality of spectral emissions S of a plurality of detection portions E of the same used refractory material sample M and / or a plurality of spectral emissions S of a plurality of detection portions E of another used refractory material sample M. The chemical composition CC of the used refractory material sample M is determined from the results of said evaluation step of said plurality of detection portions E.

Claims

1. A method for determining the chemical composition (CC) of a used refractory material sample (M), wherein during a breakdown step, a pulsed laser beam (L) is irradiated by a laser source (2) onto a detection portion (E) of the used refractory material sample (M), thereby forming a plasma in the detection portion (E), wherein during a recording step, a spectral emission (S) of the detection portion (E) is recorded by a detection unit (3), wherein during an evaluation step, spectral lines of the recorded spectral emission (S) are used by an evaluation unit (4) to determine the chemical composition in the detection portion (E), characterized in that During the evaluation step, the carbon content in the detection portion (E) is determined using a spectral line with a wavelength of approximately 193 nm, and the chemical composition (CC) of the used refractory material sample (M) is determined by using the chemical composition in the detection portion (E), and the carbon content in the detection portion (E) is determined by using auxiliary spectral lines with auxiliary wavelengths of the recorded spectral emissions, wherein an auxiliary spectral line of oxygen is used, preferably an auxiliary spectral line with a wavelength of approximately 777 nm.

2. The method according to claim 1, characterized in that During a preselection step, said detection portion (E) is determined on said used refractory material sample (M) by means of an imaging unit (5), preferably by means of a color and / or hyperspectral camera.

3. The method according to claim 1 or 2, characterized in that The spectral lines of the recorded spectral emissions (S) of one or more of the following other elements are used to determine the chemical composition in the detection portion (E) relative to the other elements in the detection portion (E), and the chemical composition (CC) of the used refractory material sample (M) is determined by using the chemical composition in the detection portion (E).

4. The method according to any one of claims 1 to 3, characterized in that The detection portion (E) is pretreated during the cleaning step, preferably, before emitting the penetrating laser beam (L), during the laser cleaning step, a cleaning laser beam is irradiated onto the detection portion (E) by the laser source (2) and / or the second laser source for pretreatment.

5. The method according to any one of claims 1 to 4, characterized in that A breakdown step, a recording step and an evaluation step are performed on multiple detection areas (E, E', E") of the used refractory material sample (M), and the chemical composition (CC) of the used refractory material sample (M) is determined from the results of the evaluation step on the multiple detection areas (E, E', E").

6. A detection device (1) for determining the chemical composition (CC) of a used refractory material sample (M), characterized in that The detection device (1) comprises a laser source (2) configured to irradiate a pulsed laser beam (L) onto a detection portion (E) of the refractory material sample (M) during a breakdown step, thereby forming plasma in the detection portion (E), the detection device (1) comprises a detection unit (3) configured to record a spectral emission (S) from the detection portion (E) during a recording step, and the detection device (1) comprises an evaluation unit (4) configured to use the spectral emission (S) during the evaluation step. The chemical composition of the detection portion (E) is determined by using the recorded spectral emissions (S), and the carbon content in the detection portion (E) is determined using a spectral line with a wavelength of about 193 nm during the evaluation step, wherein the chemical composition (CC) of the used refractory material sample (M) is determined by using the chemical composition in the detection portion (E), and the carbon content in the detection portion (E) is determined by using auxiliary spectral lines with auxiliary wavelengths of the recorded spectral emissions, wherein auxiliary spectral lines of oxygen are used, preferably auxiliary spectral lines with a wavelength of about 777 nm.

7. The detection device (1) according to claim 6, characterized in that The laser source (2) and / or the second laser source is configured to irradiate a cleaning laser beam onto the detection portion (E) during a cleaning step prior to the breakdown step.

8. The detection device (1) according to any one of claims 6 or 7, characterized in that The detection device (1) comprises an imaging unit (5), preferably a color and / or hyperspectral camera, which is configured to preselect the detection portion (E).

9. The detection device (1) according to any one of claims 6 to 8, characterized in that The laser source (2) is configured to irradiate a pulsed laser beam (L, L', L") onto a plurality of detection portions (E, E', E") of the refractory material sample (M), thereby forming plasma in the plurality of detection portions (E, E', E"), the detection unit (3) is configured to record spectral emissions (S, S', S") from the plurality of detection portions (E, E', E"), the evaluation unit (4) is configured to determine the chemical composition in the plurality of detection portions (E, E', E") using the recorded spectral emissions (S, S', S"), and the detection device (1) includes a merging unit (41), which is configured to determine the chemical composition (CC) of the used refractory material sample (M) from the chemical composition determined in the plurality of detection portions (E, E', E") 10. A refractory material sorting system (10), comprising a detection device (1) according to any one of claims 6 to 9, wherein the detection device (1) is configured to determine the chemical composition of a plurality of used refractory material samples (M), and further comprising a sorting unit (6), wherein the sorting unit (6) is configured to sort the plurality of used refractory material samples (M) based on the chemical composition (CC) of the plurality of used refractory material samples (M) during a sorting step.

11. The refractory material sorting system (10) according to claim 10, comprising a transport unit (7), preferably a conveyor belt, for transporting the plurality of used refractory material samples (M).

12. The refractory material sorting system (10) according to claim 11, comprising a feeding unit (8) for feeding the plurality of used refractory material samples (M) to the transport unit (7).

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