Method and device for analysing and sorting material parts

Abstract

The invention relates to a method for analysing and sorting material parts, in particular scrap parts made of aluminium, which is carried out in two stages, wherein presorting takes place in a first stage and post-sorting takes place in a second stage, wherein, in the first stage, in a first step, a predeterminable material property of the material parts (4) is determined by means of an analysis apparatus (2) and, in a second step of the first stage, the material parts (4) are supplied either to a first fraction (F1) or to a second fraction (F2) depending in each case on the determined material property, and wherein, in the second stage, in a first step, the material parts (4) of one of the two fractions (F1, F2) are transferred into a continuous conveying stream and subjected to prompt gamma neutron activation analysis (PGNAA) and, in a second step of the second stage, the conveying stream is fed to individual subfractions (A1 to C2) depending on an element determination obtained by the PGNAA.

Description

[0001] METHOD AND DEVICE FOR ANALYZING AND SORTING MATERIAL PARTS

[0002] The invention relates to a system for analyzing and sorting material parts, in particular aluminum scrap parts. Furthermore, the invention relates to a device for carrying out such a method.

[0003] Methods for analyzing and sorting are known from the prior art. WO 2022 / 172238, for example, describes a method for analyzing and sorting steel scrap. There, the scrap is optionally sorted in a first step using a magnetic drum, utilizing its magnetic properties. This results in a magnetic and a non-magnetic fraction. The non-magnetic fraction is discarded. The magnetic fraction, or in the case where no initial sorting step has taken place, the unsorted scrap, is subjected to analysis, and the analyzed material is divided into different fractions depending on the analysis results.

[0004] Another method for analyzing and sorting is shown in US 2013 / 0292307 A1. The process described therein aims to sort rocks or ores immediately after they have been extracted from the open-cast mine. Pre-sorting can take place according to the size of the rock. A key feature of the process is that no segregation or singulation of the material, which would limit sorting capacity, is required. High sorting efficiency is to be achieved by sorting the unsegregated, un-separated rock in a large number of sorting stages using various sensor / sorting units. The number of stages and the sensor / sorting units to be selected are determined by a mathematical model that incorporates the characteristic properties of the rock. The large number of sorting stages is necessary because each individual stage produces unsatisfactory sorting results.

[0005] A well-known method for analyzing and sorting material parts, especially aluminum scrap, enables sorting based on laser-induced plasma spectroscopy, also known as LIBS (laser-included breakdown spectroscopy). Laser-induced plasma spectroscopy is used to determine the elemental composition of a material part, i.e., a sample, using a plasma. The plasma is generated on a surface of the material part using high-intensity, focused laser radiation. Light emitted by the plasma is detected and spectrally analyzed to determine the elemental composition of the material part.

[0006] A method of the type described above is known, for example, from EP 3 352 919 B1, which also discloses a generic device for carrying out the method.

[0007] According to EP 3 352 919 B1, material parts to be sorted are fed into a feeder. The feeder can, for example, be vibrating plates that provide a feed surface along which the material parts are moved.

[0008] The feeder feeds the material pieces to be analyzed and sorted into a chute. Following gravity, the material pieces slide down the chute and exit via a lower edge of the chute. From there, the material pieces to be analyzed and sorted move in free fall through the ambient atmosphere. The feeder and the chute serve to separate the material pieces, and after exiting the chute, they are moved in free fall through a spatially defined drop corridor.

[0009] During free fall, laser-induced plasma spectroscopy is performed for each piece of material leaving the slide. For this purpose, a laser device is provided that is configured to generate a plasma on a surface of a piece of material using a laser beam propagating along a beam axis. Furthermore, a spectrometer system is provided that is configured to perform a spectral analysis of the plasma light emitted by the laser-induced plasma and to generate an output signal corresponding to the result of the spectral analysis.

[0010] This output signal, in combination with a sorting criterion, is then used by a sorting unit to direct the material parts leaving the chute into one of two fractions. For example, an air nozzle can be used as a sorting unit, which is controlled accordingly by a control device. From the stream of material parts leaving the chute, certain material parts can be sorted out under the influence of air pressure. The result is a fraction of sorted-out material parts and a fraction of non-sorted material parts.

[0011] Typically, the method described above is used to identify material components of a specific composition and separate them from material components of a different composition. Such separation occurs either because a material component of an undesired composition is identified and rejected by the sorting unit, or because the composition of a material component could not be reliably determined and therefore rejected by the sorting unit. The fraction of rejected material components is therefore composed of material components whose composition is clearly identified as undesirable, on the one hand, and material components whose composition is not clearly identified, on the other.

[0012] The fraction of material components whose composition is clearly identified and desired is also referred to as the "good fraction." The other fraction, i.e., the fraction of clearly identified and undesired material components on the one hand, and the non-clearly identified material components on the other, is also referred to as the "residual fraction."

[0013] Practice has shown that the amount of residual fraction is significantly small compared to the amount of good fraction. Since the composition of the residual fraction is undefined and therefore unknown, economic utilization of the material components belonging to the residual fraction is not possible.

[0014] Analyzed and sorted material components can then be used, in particular, to be fed into the furnace of a melting plant to provide the desired alloy composition for a subsequent casting. For example, with material components that are present as aluminum scrap, the primary goal of sorting is to select the correct aluminum alloy for the proper operation of a remelting plant.

[0015] To ensure optimal utilization of both the good and the residual fractions, analytical evaluation is necessary. The results of such an analysis can then be used to plan the loading of a remelting plant's furnace. This is done while taking into account a "safety buffer," which is necessary to safely remain within a specific target alloy range. While analytical inaccuracies can be partially compensated for in this way, the maximum possible utilization of scrap parts is adversely reduced.

[0016] The analytical inaccuracy of the evaluation is due to the fact that only a small number of samples are used for analysis, representing only a fraction of the total material to be further processed. The probability of analytical uncertainty increases with heterogeneous fractions. Thus, the residual fraction, in particular, is fundamentally not economically viable, and if so, only to a very limited extent, and with a high probability of analytical inaccuracies.

[0017] Based on the above, the object of the invention is to provide a method for analyzing and sorting material parts, in particular aluminum scrap parts, that helps minimize potential analysis errors and maximize the further usability of material parts, especially in remelting plants. Furthermore, a device for analyzing and sorting material parts, in particular aluminum scrap parts, is to be proposed.

[0018] In order to achieve the above object, a method for analyzing and sorting material parts, in particular scrap parts made of aluminum, is proposed, which is carried out in two stages, wherein in a first stage a pre-sorting and in a second stage a post-sorting takes place, wherein in the first stage in a first step a predeterminable material property of the material parts is determined by means of an analysis device and in a second step of the first stage the material parts are each fed to either a first fraction or a second fraction depending on the respectively determined material property, and wherein in the second stage in a first step the material parts of one of the two fractions are transferred into a continuous conveying stream and subjected to a prompt gamma neutron activation analysis (PGNAA for short),and in a second step of the second stage, the feed stream is fed to individual sub-fractions depending on an element determination obtained by the PGNAA.

[0019] In order to achieve the above object, a device is proposed for analyzing and sorting material parts, in particular scrap parts made of aluminum, with a first analysis device and a second analysis device, wherein the first analysis device is designed to determine a predeterminable material property of the material parts and to feed the material parts to one of two fractions by means of a sorting device, wherein the second analysis device is designed to subject the material parts of one of the two fractions to a PGNAA and to feed the material parts to individual sub-fractions depending on an element determination by the PGNAA.

[0020] The process according to the invention is carried out in two stages. A pre-sorting stage and a post-sorting stage are provided. The pre-sorting stage serves to form at least two material fractions: a good fraction and a residual fraction.

[0021] According to the invention, fractionation occurs depending on a predeterminable material property of the material parts. For this purpose, a predeterminable material property of the material parts is determined in a first step. In a second step of the first stage, the material parts are sorted, i.e., the material parts are divided into at least two fractions, namely a first fraction and a second fraction. This fractionation occurs depending on the respective determined material property of the material parts. The material parts are therefore fractionated depending on the result of the material property determination according to the first step.

[0022] According to the invention, the fractionation is carried out in such a way that at least two fractions are formed, one of the two fractions containing an increased amount of material parts which have the predeterminable material property, whereas the other fraction is formed primarily from material parts which do not have this material property.

[0023] As a material property within the meaning of the invention, one can generally be selected that expediently contributes to optimizing the desired sorting result. Particularly suitable in this sense are the respective density, absorption capacity, and / or chemical composition of the material parts as predeterminable material properties.

[0024] The fraction formation of the pre-sorting can also comprise further stages. In particular, it is possible to carry out sorting depending on a plurality of material properties to be determined. For example, it can be provided that in a first step a first predeterminable material property of the material parts is determined and in a second step the material parts are each fed to either a first fraction or a second fraction depending on the respectively determined first material property. One of the two fractions thus created is then subjected to further pre-sorting according to the invention in that in a third step a second predeterminable material property of the material parts is determined and in a fourth step the material parts are each fed to either a third fraction or a fourth fraction depending on the respectively determined second material property.

[0025] What is essential to the invention is therefore not the pre-sorting as such, but the combination of pre-sorting and post-sorting, whereby at least two fractions of material parts are present upon completion of the pre-sorting and at least one of these two fractions is subjected to a PGNAA.

[0026] As intended, pre-sorting advantageously provides a clear result with regard to the aluminum scrap parts to be sorted and thus forms the basis for proper subsequent sorting using PGNAA. It thus differs from the pre-sorting known from WO 2022 / 172238, which only utilizes the magnetic properties of steel scrap. This pre-sorting method cannot be applied to aluminum, as aluminum is not magnetic. Furthermore, the result of this type of sorting is ambiguous, as it is unclear whether the scrap parts are magnetic because they actually contain a significant portion of the iron desired for further processing or because they contain one of the equally magnetic metals cobalt or nickel.

[0027] A key advantage of combining pre-sorting and post-sorting using PGNAA only becomes apparent when pre-sorting is carried out as intended. This is because, as explained in more detail below, PGNAA can only serve as quality control if at least one well-identified fraction has been obtained through pre-sorting. According to a particular embodiment of the invention, the respective chemical composition of the material parts is determined in a first step by checking for each material part whether a predeterminable chemical component is a component of the material part. In a second step of the first stage, the material parts are each fed to either a first fraction or a second fraction depending on the presence of the predeterminable chemical component as a component of the material part.

[0028] Fraction formation is therefore preferably based on the chemical composition of the material components. For this purpose, the respective chemical composition of the material components is determined in a first step by checking whether a specific chemical component is present in each material component. If the component is present, the component is added to the good fraction; otherwise, it is added to the residual fraction. If a clear determination cannot be made for a particular component, it is added to the residual fraction.

[0029] Individual elements, such as zinc, copper, iron, or manganese, can be selected as the specified chemical component. Alternatively, groups of elements can be specified, for example, certain aluminum alloys, such as the alloys of the 5000 series or the 6000 series.

[0030] It is particularly preferable to perform the pre-sorting described above using LIBS. However, other methods can also be used, as the initial goal is simply to analyze material components according to their chemical composition and then assign them to two fractions based on the determined chemical composition.

[0031] Instead of LIBS, presorting can also be performed using X-ray sorting, for example, using X-ray transmission, especially when other material properties of the material parts are to be used as sorting criteria for presorting. For example, two-stage X-ray sorting is also possible, with a first stage of X-ray sorting for aluminum enrichment and a second stage of X-ray sorting for separation into cast and wrought alloys.

[0032] According to the invention, pre-sorting is followed by post-sorting. In this process, the material components of at least one fraction are re-sorted. However, the material components of both fractions can also be re-sorted. Preferably, in particular, a re-sorting of the residual fraction takes place. The re-sorting is carried out using PGNAA, i.e., prompt gamma neutron activation analysis. This enables online quality control, whereby all material components belonging to a fraction are analyzed—i.e., unlike the prior art, not just individual samples. This offers the particular advantage of an extremely reliable measurement, thus avoiding the inaccuracies existing in the prior art in a sample analysis provided according to the invention.The "safety buffer" that must be considered during batch optimization for furnace charging can be reduced due to the analytical accuracy achieved with the process according to the invention. This, in turn, allows for a higher proportion of usable low-grade scrap and thus lower costs for the use of primary metals and / or alloys.

[0033] Another particular advantage of PGNAA is that the material components of the analyzed fraction can be divided into subfractions depending on the average chemical composition, which is determined in real time by PGNAA.

[0034] The residual fraction, in particular, contains material components that vary greatly in their chemical composition. The economic value of the usability of the residual fraction is determined by the content of alloying elements it contains, particularly alloying elements such as zinc and copper. The method according to the invention allows the actual chemical composition of the material components to be determined online, i.e., in real time, which then allows the material components to be further divided into individual sub-fractions. In this way, separate sub-fractions are created that, due to their known chemical composition, have a higher economic value than an unseparated mixture.The process implementation according to the invention can therefore contribute to increasing the economic viability of the material components contained in the fractions, thereby simultaneously reducing unwanted downcycling. Furthermore, additional quality assurance is provided.

[0035] Prompt gamma neutron activation analysis enables multi-element measurement of the material components of a fraction moving in a conveying stream. According to the invention, the material components of one of the two fractions are transferred into a continuous conveying stream in a first step of the second stage. The material components are then subjected to PGNAA. The advantage of PGNAA is that it is continuously measured across the entire conveying stream cross-section, allowing a representative elemental determination. Elements such as copper can be measured with an accuracy of up to 0.02% copper, which allows the formation of subfractions that can be clearly distinguished from one another.

[0036] In a second step of the second stage, the flow of material parts is divided into individual sub-fractions, which is done depending on the element determination obtained by PGNAA.

[0037] The advantageous result of the process according to the invention is that material components can be sorted based on the economic value of selected alloying elements such as copper, zinc, iron, or manganese. This analysis is not based on representative samples, but rather a complete analysis of all material components belonging to a fraction, and this is done in real time, allowing online operation. Analysis inaccuracies are minimized, which allows for a reduction in the "safety buffer" required for proper operation of a foundry, which in turn allows for a reduced use of primary metals.

[0038] According to a further feature of the invention, the two stages are carried out immediately one after the other. Thus, a pre-sorting step takes place, immediately followed by a post-sorting step. The fractions resulting from the pre-sorting step are further processed after the pre-sorting step and subjected to the second sorting step provided by the invention. This allows for a temporally and spatially optimized process implementation.

[0039] Alternatively, it is of course also possible to decouple the two process steps according to the invention from each other in time. In particular, it is permitted to temporarily store the fractions resulting from a pre-sorting of the intended type and only later subject them to a subsequent sorting of the inventive type. Such a delayed two-stage sorting can prove advantageous, particularly for logistical reasons. In particular, fractions from the pre-sorting can be collected and then jointly re-sorted in the manner described above.

[0040] According to a further feature of the invention, not only the material components of one fraction, but also the material components of both fractions are subjected to PGNAA. The fractions are processed separately, thus reliably preventing unintentional mixing of the material components previously divided into two fractions.

[0041] According to a further feature of the invention, the chemical composition of the material particles is determined in the first stage using LIBS. Since the LIBS process produces very reliable good fractions, it is particularly preferable to further process the residual fraction using PGNAA after pre-sorting using LIBS. However, the good fraction produced by the LIBS process can also, of course, be subjected to post-sorting using PGNAA.

[0042] According to a further feature of the invention, it is provided that a characteristic component of a specific aluminum alloy is selected as the predeterminable chemical component.

[0043] Certain individual chemical elements are characteristic of certain aluminum alloys. In order to distinguish one aluminum alloy from another, it is therefore not necessary to analyze all of the alloy components of a piece of material to be sorted. Determining just one alloying element can therefore be sufficient to clearly distinguish between two aluminum alloys. This is particularly the case if the alloy composition contains expected components. For example, if a scrap mixture to be sorted contains material components of only two aluminum alloys, only these two aluminum alloys are expected. If these two expected aluminum alloys differ in a characteristic alloying element, it is sufficient to determine the chemical composition of the material components based on this alloying element.

[0044] According to a further feature of the invention, in the second stage of element determination using PGNAA, alloying elements from the group zinc, copper, iron, and manganese are taken into account. These alloying elements are particularly important from a business perspective, which is why it is advantageous to divide the flow of material particles into subfractions representing these alloying elements.

[0045] The device according to the invention serves, in particular, to carry out the method according to the invention. For this purpose, the device proposed by the invention has a first analysis device and a second analysis device. The first analysis device serves for pre-sorting according to the first process stage, and the second analysis device serves for post-sorting according to the second process stage. The two analysis devices can be coupled to one another by conveyor technology, which allows the two process stages to be carried out immediately one after the other.

[0046] The first analysis device is configured to determine a predeterminable material property of the material parts and to fractionate the material parts using a sorting device. A predeterminable material property within the meaning of the invention can be, in particular, density, absorption capacity, and chemical composition. The first analysis device is to be designed accordingly so that the material parts can be sorted according to the desired material property.

[0047] According to a particularly preferred embodiment of the invention, the first analysis device is configured, in particular, to determine the chemical composition of the material parts by testing each material part to determine whether a predeterminable chemical component is a component of the material part. This test can be carried out in the manner already described, preferably using LIBS.

[0048] The first analysis device has a sorting device that sorts the material particles into one of two fractions. This preferably results in a good fraction on the one hand and a residual fraction on the other, depending on the previously conducted material analysis, for example, based on the chemical composition of the material particles.

[0049] The second analysis device is designed to subject the material components of one of the two fractions to a PGNAA and then to separate the material components into individual subfractions based on the elemental determination by the PGNAA. The analysis of the material components takes place in real time, allowing for immediate sorting of the material components moving along the conveyor stream into individual subfractions.

[0050] According to a further feature of the invention, it is provided that the first analysis device enables analysis by means of LIBS, for which purpose the first analysis device comprises: a sorting unit configured to feed a material part to one of two fractions, a laser device configured to generate a plasma on a surface of the material part using a laser beam propagating along a beam axis, a spectrometer system configured to carry out a spectral analysis of a plasma light emitted by the laser-induced plasma and to generate an output signal in accordance with a result of the spectral analysis carried out, and a control device configured to receive the output signal and to operate the sorting unit based on the output signal and a sorting criterion.

[0051] The spectrometer system, in turn, comprises a spectrometer and a detection unit optically connected to the spectrometer. The detection unit has an objective lens with a detection cone that forms a plasma detection zone in an overlap area with the laser beam.

[0052] By means of an analysis device equipped in this way, the chemical composition of a material part can be determined by means of LIBS in a manner known per se, whereby the device can be set to a specific predeterminable element or a specific predeterminable alloy, for example an aluminum alloy.

[0053] According to a further feature of the invention, the second analysis device comprises a transport device with conveyor belts for transporting the material parts in a continuous flow. The conveyor belts serve to transfer the material parts into a flow, specifically a flow of a predeterminable width and height. The geometric design of the flow depends in particular on the detection unit to be used for PGNAA.

[0054] According to a further feature of the invention, the second analysis device comprises a detection unit having a neutron source arranged beneath a conveyor belt and a detector arranged above the conveyor belt and opposite the neutron source. This enables a comprehensive scanning of the conveyed stream, so that, given a known conveyor speed, it is possible to calculate which conveyor belt length is occupied by material particles of a specific average chemical composition. This allows the conveyed stream to be assigned to individual subfractions in a time-controlled manner, which allows the conveyed stream to be fed to different, separate subfractions in a simple yet effective manner. A reversed arrangement of neutron source and detector is of course also possible.

[0055] According to a further feature of the invention, it is provided that separate compartments are arranged downstream of the detection unit in the transport direction of the conveyor belt, wherein the compartments each serve to receive material parts of a sub-fraction.

[0056] Compartments are provided to divide the flow into different sub-fractions. These compartments represent spatially separated collection points for the material components, with one collection point provided for each sub-fraction. Such a collection point can be formed, for example, by a box, a container, and / or the like. The only important thing is that these compartments are located downstream of the detection unit in the transport direction of the material components, so that after PGNAA has been completed, the flow can be allocated to the individual compartments as intended.

[0057] According to a further feature of the invention, each compartment is assigned a circulating conveyor belt that is arranged vertically above the compartment. The individual compartments are arranged one behind the other in the transport direction of the partial material flow. Above the compartments, individual conveyor belts are provided, which are also connected one behind the other in the transport direction, so that the flow of material parts can be transferred from conveyor belt to conveyor belt. Each compartment is assigned a conveyor belt, whereby the flow can be passed on from compartment to compartment by means of the respective associated conveyor belt. The design according to the invention therefore makes it possible, depending on the conveyor belts used, to specifically feed the material flow fed into them to individual compartments.

[0058] According to a further feature of the invention, the conveyor belts are each inclined relative to the horizontal. They thus have a first end section and a second end section, with the two end sections being at different heights. A rear end section of a conveyor belt, in the conveying direction, projects beyond a front end section, in the transport direction, of a conveyor belt arranged downstream of the first conveyor belt.

[0059] According to a further feature of the invention, the running direction of the conveyor belts is reversible. In combination with the inclination of the conveyor belts to the horizontal, this ensures a targeted allocation of the conveyed material flow to the individual compartments in a simple yet effective manner. This is because the conveyor belts running in the direction of transport transport the material flow from conveyor belt to conveyor belt, all the way to the conveyor belt that rotates in the opposite direction. This conveyor belt rotating in the opposite direction conveys the material fed onto it into its associated compartment. If a different compartment needs to be served, the running direction of this conveyor belt is reversed again. In a technically simple yet effective manner, this allows a targeted distribution of the conveyed flow of material components to individual compartments.

[0060] Further features and advantages of the invention will become apparent from the following description with reference to the figures.

[0061] Fig. 1 shows a schematic representation of a first analysis device of the device according to the invention; Fig. 2 shows a schematic representation of a second analysis device of the device according to the invention and

[0062] Fig. 3 shows a schematic representation of a device according to the invention and its mode of operation.

[0063] Fig. 3 shows a schematic representation of a device 1 according to the invention for analyzing and sorting material parts 4. The device 1 according to the invention has a first analysis device 2 and a second analysis device 3. These are shown in more detail in Figures 1 and 2, as will become apparent from the further explanations.

[0064] Fig. 1 shows a schematic representation of the first analysis device 2. This device is used to sort material particles 4 based on laser-induced plasma spectroscopy, also referred to as LIBS, and to assign them to two fractions F1 and F2.

[0065] The first analysis device 2 shown in Fig. 1 is configured to subject a material part 4 to laser-induced plasma spectroscopy and to sort it depending on the result of the spectral analysis. In the illustrated embodiment, two fractions F1 and F2 are provided, to which the material part 4 can be assigned. Collection points 5, for example in the form of containers, serve to receive the respective fractions F1 and F2.

[0066] As can be seen from the schematic representation in Fig. 1, the analysis device 2 has a feed means 6 followed by a chute 9. In the intended use, a material part 4 is fed to the feed means 6. The feed means 6 serves to transport the material part 4 along a feed surface 7 provided by the feed means 6, specifically up to an upper section 8 of the chute 9. Here, the material part 4 is transferred from the feed means 6 to the chute 9.

[0067] The feeding means 6 serves in particular to separate a plurality of material parts 4 fed onto the feeding means 6, so that they can then be fed to the chute 9 at a distance from one another.

[0068] A piece of material 4 transferred to the chute 9 slides down the chute 9 under the force of gravity until it reaches the lower edge 10 of the chute 9, which is located opposite the upper section 8 of the chute 9. The particular task of the chute 9 is to align the piece of material 4 and transfer it into a defined fall corridor. Upon leaving the chute 9, the piece of material 4 continues to fall in free fall through the ambient atmosphere under the influence of gravity. In doing so, it passes through a spectrometer system 11. This ensures that the piece of material 4 is analyzed. In accordance with the result of a spectral analysis carried out, the spectrometer system 11 generates an output signal. This is fed to a control device 12, which operates, i.e. controls, a sorting unit 13 depending on this output signal on the one hand and a stored sorting criterion on the other.By means of this sorting unit 13, the material part 4 is either deflected in its free fall or no deflection occurs. If no deflection occurs, the material part 4 reaches the collection point 5 for fraction F2. Otherwise, if sorting takes place by means of the sorting unit 13, the material part 4 reaches the collection point 5 for fraction F1.

[0069] The spectrometer system 11, which is part of a LIBS module 14, is used to analyze the composition of the material part 4. The LIBS module 14 also includes a laser device 15 and the control device 12. Preferably, the laser device 15, the spectrometer system 11, and the control device 12 are housed in a common housing, which is not shown in detail in Fig. 1.

[0070] The laser device 15 in turn has further individual components, for example a laser beam source, an optical fiber and a focusing optics.

[0071] The spectrometer system 11 further comprises a detection unit, which in turn provides several lenses. Each of these lenses is assigned a detection cone 16, which each form a plasma detection region 18 in an overlap region with a laser beam 17 emitted by the laser device 15. These plasma detection regions 18 are arranged offset from one another along the beam axis of the laser beam 17 and together form a field of view of the detection unit. The field of view is thus composed of the individual plasma detection regions, whereby the total area covered by the detection unit

[0072] A detection zone is defined. As soon as a material part 4 passes the detection zone, it is bombarded with a laser beam, resulting in laser-induced plasma being generated on the surface of the material part 4. This plasma is analyzed in the manner already described using the spectrometer system 11, and depending on the analysis result, the material part 4 is deflected by the sorting unit 13. The sorting unit 13 can, in particular, comprise an air nozzle, which, when pressurized, enables the material part 4 to be sorted out.

[0073] Fig. 2 shows a schematic representation of the second analysis device 3 of the device 1 according to the invention.

[0074] In the illustrated embodiment, the second analysis device 3 serves to re-sort the material parts 4 of the first fraction F1 stored in a bunker 20. Such re-sorting can also be performed for the material parts 4 of the second fraction F2.

[0075] By means of the second analysis device 3, the material parts 4 are converted into subfractions, with a separate compartment 29 being provided for each subfraction, for example in the form of a container. In the illustrated embodiment, a total of eight subfractions are provided, namely subfractions A1, A2, B1, B2, B3, B4, C1, and C2. It can be provided that subfractions A1 and A2 have a first alloying element in common, but then differ with respect to a second alloying element. The same applies to the other subfractions, with the subfractions of group B differing with respect to four possible additional alloying elements.

[0076] A transport device 23, which has a plurality of conveyor belts 21, 24, 25, and 30, is used to transport the material parts 4 from the bunker 20 to the individual compartments 29. The conveyor belts 21, 24, 25, and 30 are arranged one behind the other in the transport direction from the bunker 20 to the compartments 29.

[0077] By means of the transport device 23, the material parts 4 originating from the bunker 20 are transferred into a continuous conveying stream, which is then subjected to a PGNAA. The conveying stream is then fed into the individual subfractions A1 to C2 depending on the element determination obtained by the PGNAA. The first conveyor belt 21 in the transport direction is equipped with a belt scale 22. The belt scale 22 determines the total weight of the material parts 4 discharged onto the first conveyor belt 21, so that the speed of the conveyor belt 21 can be adjusted based on this weight in order to even out the conveying stream.

[0078] The material flow is transferred from the first conveyor belt 21 to a second conveyor belt 24. This conveyor belt contains a detection unit 26 for performing PGNAA. For this purpose, the detection unit 26 has a neutron source 27 and a detector 28 arranged opposite the neutron source 27. In a conventional manner, the PGNAA results in an elemental determination corresponding to the chemical composition of the material parts 4.

[0079] The analyzed material parts 4 are then transferred to another conveyor belt 25, which is followed by further conveyor belts 30 in the transport direction. A conveyor belt 30 is assigned to each compartment 29. For example, the first conveyor belt 30 in the transport direction is assigned to sub-fraction A1, and the second conveyor belt 30 following in the transport direction is assigned to sub-fraction A2, etc.

[0080] The conveyor belts 30 are designed to be reversible in their running direction, i.e. they can run clockwise as well as in the opposite direction.

[0081] By reversing the running direction of individual conveyor belts 30, the conveying flow can be directed in a targeted manner to individual compartments 29 and thus to individual sub-fractions.

[0082] If all conveyor belts 30 rotate clockwise, the conveying flow is transferred from conveyor belt 30 to conveyor belt 30 until the last conveyor belt 30 in the transport direction is reached, from where the conveying flow then falls into the compartment 29 of the sub-fraction C2.

[0083] As soon as the direction of rotation of one of the conveyor belts 30 is reversed, the conveying flow supplied to this conveyor belt 30 is no longer conveyed in the direction of transport, but in the opposite direction, with the result that it is transferred to the compartment 29 assigned to this conveyor belt 30. By changing the direction of travel of the conveyor belts 30, a targeted allocation of the volume flow to the individual compartments 29 can be carried out.

[0084] The switching of the running direction of the conveyor belts 30 occurs as a function of time and the transport speed. For example, if a certain average chemical composition of the conveyed stream is detected by the detection unit 26 for a running time of, for example, 10 seconds, the subfraction corresponding to this average chemical composition can be determined, and then it can be calculated how long it will take until the detected section of the conveyed stream reaches the associated conveyor belt 30. Furthermore, it can be calculated how long the conveyor belt 30 must be operated in the reverse direction once it has reached this conveyor belt 30 so that the previously detected section of the conveyed stream can be fed to the corresponding compartment 29.

[0085] Finally, Fig. 3 shows a summary of the device 1 according to the invention. As can be seen from this illustration by way of example, the material components of both fractions F1 and F2, which originate from the first analysis device 2, are each re-sorted by means of a second analysis device 3. For this purpose, conveyor belts 19 are provided, which feed the fractions F1 and F2 to respective bunkers 20. From there, re-sorting then takes place in accordance with the explanations with reference to Fig. 2. Fig. 2 shows the second analysis device 3 in a schematic side view, whereas Fig. 3 shows a schematic view from above.

[0086] Reference symbol

[0087] 1 Device 18 Plasma detection area

[0088] 2 first analysis device 20 19 conveyor belt

[0089] 3 second analysis device 20 bunker 4 material section 21 conveyor belt

[0090] 5 Collection point 22 Belt scale

[0091] 6 Feeding means 23 Transport device

[0092] 7 Feed area 25 24 Conveyor belt

[0093] 8 upper section 25 conveyor belt 9 chute 26 detection unit

[0094] 10 lower edge 27 source

[0095] 11 spectrometer system 28 detector

[0096] 12 Control device 3o 29 compartment

[0097] 13 Sorting unit 30 Conveyor belt 14 LIBS module

[0098] 15 laser device F1 / F1 fraction

[0099] 16 detection cones A1-C2 subfraction

[0100] 17 Laser beam

Claims

Patent claims 1. A method for analyzing and sorting material parts, in particular scrap parts made of aluminum, which is carried out in two stages, wherein in a first stage a pre-sorting and in a second stage a post-sorting takes place, wherein in the first stage in a first step a predeterminable material property of the material parts (4) is determined by means of an analysis device (2) and in a second step of the first stage the material parts (4) are each fed to either a first fraction (F1) or a second fraction (F2) depending on the respectively determined material property, and wherein in the second stage in a first step the material parts (4) are assigned to one of the two fractions (F1),(F2) are transferred into a continuous feed stream and subjected to a prompt gamma neutron activation analysis (PGNAA) and, in a second step of the second stage, the feed stream is fed into individual sub-fractions (A1 to C2) depending on an element determination obtained by the PGNAA.

2. Method according to claim, characterized in that the two stages are carried out immediately one after the other.

3. Method according to claim 1 or 2, characterized in that the material parts (4) of both fractions (F1, F2) are each subjected to a PGNAA.

4. Method according to one of the preceding claims, characterized in that the respective density, the absorption capacity, the chemical composition and / or the like of the material parts (4) is selected as the predeterminable material property of the material parts (4).

5. Method according to claim 4, characterized in that in the first step of the first stage the respective chemical composition of the material parts (4) is determined by checking for each material part (4) whether a predeterminable chemical component is a component of the material part (4), and in a second step of the first stage the material parts (4) are each fed to either the first fraction (F1) or the second fraction (F2) depending on the presence of the predeterminable chemical component as a component of the material part (4).

6. Method according to claim 5, characterized in that the determination of the chemical composition of the material parts (4) in the first stage is carried out by means of LIBS.

7. Method according to claim 5 or 6, characterized in that a characteristic component of a specific aluminum alloy is selected as the predeterminable chemical component.

8. Method according to one of the preceding claims 5 to 7, characterized in that in the second stage of the element determination by means of PGNAA, in particular alloying elements from the group Zn, Cu, Fe and Mn are taken into account.

9. Device for analyzing and sorting material parts, in particular scrap parts made of aluminum, with a first analysis device (2) and a second analysis device (3), wherein the first analysis device (2) is set up to determine a predeterminable material property of the material parts (4) and to feed the material parts (4) to one of two fractions (F1, F2) by means of a sorting device (12), wherein the second analysis device (3) is set up to subject the material parts (4) of one of the two fractions (F1, F2) to a PGNAA and to feed the material parts (4) to individual sub-fractions (A1 to C2) depending on an element determination by the PGNAA.

10. Device according to claim 9, characterized in that the first analysis device (2) is designed to determine the chemical composition of the material parts (4) by checking for each material part (4) whether a predeterminable chemical component is a component of the material part (4).

11. Device according to claim 10, characterized in that the first analysis device (2) comprises: a sorting unit (13) which is designed to feed the material part (4) to one of two fractions (F1, F2), a laser device (15) configured to generate a plasma on a surface of the material part (4) using a laser beam (17) propagating along a beam axis, a spectrometer system (11) configured to perform a spectral analysis of a plasma light emitted by the laser-induced plasma and to generate an output signal in accordance with a result of the spectral analysis performed, and a control device (12) configured to receive the output signal and to operate the sorting unit (13) based on the output signal and a sorting criterion.

12. Device according to one of the preceding claims 9 to 11, characterized in that the second analysis device (3) has a detection unit (26) which has a neutron source (27) and a detector (28) opposite the neutron source (27) or only one detector (28), wherein the detector (28) is arranged above, below or to the side of the conveyor belt (24).

13. Device according to one of the preceding claims 9 to 12, characterized in that separate compartments (29) are arranged downstream of the detection unit (26) in the transport direction of the transport device (23), wherein the compartments (29) each serve to receive material parts (4) of a sub-fraction (A1 to C2).

14. Device according to claim 13, characterized in that each compartment (29) is assigned a circulating conveyor belt (30) which is arranged in the vertical direction above the compartment (29).

15. Device according to claim 14, characterized in that the running direction of the conveyor belts (30) is reversible.

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