Method and device for analyzing and sorting material parts

Abstract

The present invention relates to a method for analyzing and sorting a plurality of material parts, in particular scrap parts made of aluminum, which is carried out in two stages, with a first stage being a pre-sorting and a second stage being a post-sorting, in which in a first step of the first stage, predetermined material properties of the material parts (4) are identified by an analytical device (2), in a second step of the first stage, the material parts (4) are fed into one of two fractions, i.e., a first fraction (F1) or a second fraction (F2), depending on the identified material properties, in a first step of the second stage, the material parts (4) in one of the two fractions (F1, F2) are transferred in a continuous transport stream and subjected to prompt gamma neutron activation analysis (PGNAA), and in a second step of the second stage, the transport stream is fed into individual subfractions (A1 to C2) depending on the elemental identification results obtained by the PGNAA.

Description

[Technical Field]

[0001] The present invention relates to a system for analyzing and sorting material parts, in particular scrap parts made of aluminum. The invention also relates to a device for carrying out such a method. [Background technology]

[0002] Methods for analysis and sorting are known per se from the prior art. One method for analyzing and sorting steel scrap is described, for example, in US Pat. No. 5,629,499. In this method, the scrap is optionally sorted in a first step using a magnetic drum, taking advantage of the steel scrap's magnetic properties. In this way, a magnetic fraction and a non-magnetic fraction are obtained. The non-magnetic fraction is rejected. The magnetic fraction, or the unsorted scrap if the first step was not performed, is subjected to analysis, and the analyzed material is separated into different fractions depending on the results of the analysis.

[0003] A further method for analysis and sorting is shown in Patent Document 2. The objective of the method shown there is to subject rock or ore to a sorting procedure immediately after extraction in an open-cut mine. Pre-sorting may be performed depending on the size of the rock. It is important that this method does not require segregation or individualization of materials, which could limit the sorting capacity. High sorting efficiency is achieved by sorting unsegregated, unindividualized rock in multiple sorting stages using various sensors / sorting units. The number of stages and the selected sensors / sorting units are determined by a mathematical model that includes the characteristic properties of the rock. Multiple sorting stages are required because each individual stage achieves insufficient sorting results.

[0004] Methods for analyzing and sorting material parts, particularly scrap parts made of aluminum, well known in the prior art allow sorting based on laser-induced plasma spectroscopy, also known as LIBS (Laser-Induced Breakdown Spectroscopy). In this case, laser-induced plasma spectroscopy is used to determine the elemental specific composition of a material part (i.e., a sample) using a plasma. The plasma is generated on the surface of the material part using high-intensity, focused laser radiation. The light emitted from the plasma is detected and evaluated spectroscopically to infer the elemental composition of the material part.

[0005] A method of the above mentioned type is known, for example, from US Pat. No. 5,629,399, which also discloses a general device for carrying out the method. According to Patent Document 3, material parts to be sorted are fed to a feeding means. The feeding means may be, for example, a vibrating plate that provides a feeding surface along which the material parts are moved. The parts to be analyzed and sorted are fed to the chute by the feeding means. The parts slide down the chute under the force of gravity and leave the chute through the lower edge of the chute. From here, the parts to be analyzed and sorted move in free fall in the ambient atmosphere. The feeding means and the chute serve to separate the material parts, which, after leaving the chute, move in free fall through a spatially determined falling path.

[0006] Laser-induced plasma spectroscopy is performed on each material piece leaving the chute during free fall. To this end, a laser device is provided configured to generate a plasma on the surface of the material piece using a laser beam propagating along a beam axis. Furthermore, a spectrometer system is provided configured to perform a spectral analysis of plasma light detected by the laser-induced plasma and to generate an output signal corresponding to the result of the performed spectral analysis.

[0007] This output signal is then used in combination with sorting criteria in the sorting unit to direct the material parts leaving the chute into one of two fractions. For example, an air nozzle appropriately controlled by a control device can be used as the sorting unit. In this way, specific material parts can be sorted by air pressure from the stream of material parts leaving the chute. This results in a fraction of sorted material parts and a fraction of unsorted material parts.

[0008] Typically, the above-mentioned methods serve to identify material parts of a specific composition and separate them from material parts of a different composition. In this case, such separation is performed either because material parts of an undesired composition are identified by the sorting unit and rejected, or because the composition of the material parts cannot be reliably identified and therefore the rejection by the sorting unit occurs. The rejected fraction of material parts therefore consists, on the one hand, of material parts whose composition is clearly identified and undesired, and, on the other hand, of material parts whose composition is not clearly identified.

[0009] The fraction of material components with a clearly identified and desired composition is also called the "good fraction." The other fractions (i.e., the clearly identified and undesired material component fractions on the one hand, and the non-clearly identified material component fractions on the other hand) are also called the "remaining fraction."

[0010] In practice, it has been shown that the amount of the residual fraction is not so small as to be negligible compared to the amount of the good fraction. Since the composition of the residual fraction has not been determined and is therefore unknown, it is not possible to economically recycle the material components belonging to the residual fraction.

[0011] The analyzed and sorted material components can be used to feed the furnaces of a smelting plant, in particular to provide the desired alloy composition for subsequent casting. For example, in the case of material available as aluminum scrap, the main purpose of sorting is to select the correct aluminum alloy for the proper operation of the remelting plant.

[0012] Analytical evaluation is necessary to ensure the best possible use of both good and rejected scrap. The results of such analysis can then also be used to plan the furnace charges in the remelting plant. This is done taking into account the "safety buffers" necessary to stay within a specific target alloy window. In this way, analytical inaccuracies can be partially compensated for, while the maximum possible use of scrap parts is disadvantageously reduced.

[0013] The analytical inaccuracy in the evaluation is due to the fact that only a small number of samples are used for the analysis, which represents only a small portion of the total material component to be further processed. In the case of heterogeneously formed fractions, the probability of analytical uncertainty increases. Therefore, especially the residual fraction cannot be economically recycled further, or even if it can be recycled, it can only be recycled to a very limited extent, and the probability of analytical inaccuracy is high. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] International Publication No. 2022 / 172238 [Patent Document 2] US Patent Application Publication No. 2013 / 0292307 [Patent Document 3] European Patent No. 3352919 Summary of the Invention [Problem to be solved by the invention]

[0015] Based on the above, it is an object of the present invention to provide a method for analyzing and sorting material parts, in particular scrap parts made of aluminum, which method serves to minimize possible analytical errors and maximize the further usability of the material parts, in particular in remelting plants. Furthermore, a device for analyzing and sorting material parts, in particular scrap parts made of aluminum, is proposed. [Means for solving the problem]

[0016] In order to achieve the above object, in terms of a method, a method for analyzing and sorting a plurality of material parts, in particular scrap parts made of aluminum, is proposed, which is carried out in two stages, with pre-sorting in a first stage and post-sorting in a second stage, in which in a first step of the first stage, predetermined material properties of the material parts are identified by an analytical device, in a second step of the first stage, the material parts are fed into two fractions, i.e., the first fraction or the second fraction, respectively, depending on the identified material properties, in a first step of the second stage, the material parts of one of the two fractions are transferred in a continuous transport stream and subjected to prompt gamma neutron activation analysis (PGNAA for short), and in a second step of the second stage, the transport stream is fed into individual sub-fractions depending on the elemental identification results obtained by the PGNAA.

[0017] In order to achieve the above object, in terms of a device, a device for analyzing and sorting a plurality of materials, in particular scrap parts made of aluminum, is proposed, comprising a first analytical device and a second analytical device, wherein the first analytical device is configured to identify predetermined material properties of the material parts and to supply the material parts to one of two fractions by a sorting device, and the second analytical device is configured to subject the material parts of one of the two fractions to PGNAA and to supply the material to individual subfractions depending on the elemental identification results by the PGNAA.

[0018] According to the invention, the method is carried out in two stages, with pre-sorting on the one hand and post-sorting on the other hand, which serves to form two or more material fractions, namely a good fraction on the one hand and a residual fraction on the other hand.

[0019] According to the present invention, the formation of fractions is carried out according to predetermined material properties of the material components. For this purpose, in a first step, the predetermined material properties of the material components are determined. In a second step of the first stage, the material components are sorted, i.e., separated into two or more fractions (i.e., a first fraction and a second fraction). The formation of fractions is carried out according to the material properties of the material components, which are determined in each case. As a result, the material is fractionated according to the results of the determination of the material properties in the first step.

[0020] Thus, according to the invention, fractionation is carried out in such a way that two or more fractions are formed, one of the two fractions containing more material components exhibiting a given material property, while the other fraction is mainly composed of material components that do not have this property.

[0021] In the sense of the present invention, the material properties can essentially be those that advantageously contribute to optimizing the desired sorting result, with the density, absorption capacity and / or chemical composition of each of the material parts being selected in this sense as particularly suitable material properties of the material parts.

[0022] The formation of fractions can also include additional steps. In particular, sorting can be performed according to a plurality of material properties to be identified. For example, in a first step, a predetermined first material property of a plurality of material components can be identified, and in a second step, each of the plurality of material components can be supplied to either the first fraction or the second fraction depending on the identified first material property. One of the two obtained fractions can then be subjected to further pre-sorting according to the present invention, and in a third step, a predetermined second material property of the plurality of material components can be identified, and in a fourth step, each of the plurality of material components can be supplied to either the third fraction or the fourth fraction depending on the identified second material property.

[0023] Therefore, what is important to the present invention is not the pre-sorting itself, but the combination of pre-sorting and post-sorting, where two or more fractions of material components are present at the end of pre-sorting, and one or more of these two fractions are subjected to PGNAA.

[0024] As intended, pre-sorting advantageously provides clear results regarding the aluminum scrap parts to be sorted, thus providing a basis for appropriate post-sorting using PGNAA. It therefore differs from the pre-sorting known from U.S. Patent No. 5,629,999, because in U.S. Patent No. 5,629,999, sorting is performed solely using the magnetic properties of the steel scrap. This pre-sorting method cannot be applied to aluminum, since aluminum is not magnetic. Furthermore, the results of such sorting are ambiguous, since it is not clear whether the scrap parts are magnetic because they actually contain a significant proportion of iron, which is desirable for further processing, or whether they are magnetic because they contain one of the equally magnetic metals, cobalt or nickel.

[0025] The significant advantage of the combination of pre-sorting and post-sorting using PGNAA is realized only through intended pre-sorting, because PGNAA can only serve as a quality control if one or more already sufficiently identified fractions are obtained by pre-sorting, as will be explained in more detail below. According to a specific embodiment of the present invention, in a first step of the first stage, the chemical composition of each of the plurality of material parts is identified by testing each material part for the presence of a predetermined chemical component in the material part, and in a second step of the first stage, the plurality of material parts are supplied to either the first fraction or the second fraction depending on the presence of the predetermined chemical component as a component of the material part.

[0026] Therefore, the fractions are preferably formed according to the chemical composition of the material components. For this purpose, in a first step, the chemical composition of each of the plurality of material components is identified by checking for each material component whether a predetermined chemical component is a component of the material. If the answer is yes, this material component is added to the good fraction; otherwise, it is added to the residual fraction. If a material component cannot be clearly identified, it is added to the residual fraction.

[0027] Individual elements such as zinc, copper, iron, or manganese can be selected as the predetermined chemical constituent, or alternatively, a group of elements can be predetermined, for example, a particular aluminum alloy such as a 5000 or 6000 series alloy.

[0028] It is particularly preferred to use LIBS to carry out the above pre-sorting, however, other methods can also be used, since the initial objective is simply to analyze the material components according to their chemical composition and then assign the material components to two fractions according to their specific chemical composition.

[0029] Pre-sorting can also be performed using X-ray sorting (e.g., X-ray transmission) instead of LIBS, especially if other material properties of the material components are used as sorting criteria for pre-sorting. For example, a two-stage X-ray sorting is also possible, where a first stage is X-ray sorting for aluminum enrichment and a second stage is X-ray sorting for separating cast and wrought alloys.

[0030] According to the invention, pre-sorting is followed by post-sorting. The material components of one or more fractions are post-sorted. However, it is also possible to post-sort the material components of both fractions. Preferably, the residual fraction in particular is post-sorted.

[0031] Post-sorting is carried out using PGNAA (i.e., prompt gamma neutron activation analysis). This allows for online quality control, in which, in contrast to the prior art, not only individual samples but all material components belonging to a fraction are analyzed. This has the particular advantage of extremely reliable measurements, which avoids the inaccuracies present in the prior art when analyzing samples according to the invention. The "safety buffer" taken into account in batch optimization for furnace charging can be reduced due to the analytical precision achieved using the method according to the invention. This, in turn, allows for a higher proportion of usable low-grade scrap and therefore lower costs for using primary metals and / or alloys.

[0032] Another particular advantage of PGNAA is that it allows the material components of the analyzed fraction to be supplied to subfractions according to the average chemical composition determined in real time by PGNAA.

[0033] The residual fraction contains material components with significantly different chemical compositions. The economic value of the residual fraction in recycling is determined by the content of alloying elements (especially zinc and copper). The method according to the present invention allows the actual chemical composition to be determined online, i.e., in real time, which then allows multiple material components to be supplied to the individual subfractions. In this way, distinct subfractions are generated that have a higher economic value than unseparated mixtures because their chemical compositions are known. Therefore, implementing the method according to the present invention can contribute to increasing the economic usefulness of the material components contained in the fractions, while simultaneously reducing undesired downcycling. Furthermore, additional quality assurance is provided.

[0034] Prompt gamma neutron activation analysis allows multi-elemental measurement of material components in fractions moving in a transport stream. Therefore, according to the present invention, the first step of the second stage provides a process in which material components in one of the two fractions are transferred to a continuous transport stream. The material components are then subjected to PGNAA. The advantage of PGNAA is that measurements are performed continuously over the entire cross-section of the transport stream, resulting in representative element identification. For example, elements such as copper can be measured with an accuracy of up to 0.02%, which allows the formation of subfractions that are distinguishable from each other in a defined manner.

[0035] In the second step of the second stage, a delivery stream of material components is provided for individual subfractions depending on the elemental identification results obtained by PGNAA. As a result of implementing the method according to the present invention, it is possible to advantageously separate material components according to the economic value of selected alloying elements, such as copper, zinc, iron, or manganese. Instead of analyzing a representative sample, a complete analysis of all material components belonging to a fraction is performed in real time, making online operation possible. Analytical inaccuracies are minimized, thereby reducing the "safety buffer" maintained for the planned operation of the foundry, thereby reducing the use of primary metal.

[0036] According to another feature of the invention, both steps are carried out immediately one after the other. Thus, pre-sorting is carried out, followed immediately by post-sorting. The fraction obtained from pre-sorting is then further processed after pre-sorting and subjected to the second sorting step according to the invention. This makes it possible to optimize the process in terms of time and space.

[0037] However, it is of course also possible, instead, to separate the two process steps according to the invention in terms of time. In particular, it is possible to temporarily store the fractions obtained from the intended type of pre-sorting and only later supply them to the type of post-sorting according to the invention. Such a delayed two-stage sorting can prove to be advantageous, especially for logistical reasons. In particular, it is possible to collect the fractions from the pre-sorting and then post-sort them together in the manner described above.

[0038] According to a further feature of the invention, it is provided that not only material components of one fraction but also material components of both fractions are subjected to PGNAA, in which case the fractions are treated separately from each other so as to avoid unintentional mixing of material components previously separated into the two fractions.

[0039] According to a further feature of the invention, the determination of the chemical composition of the material components in the first stage is performed by LIBS. Since the LIBS method very reliably produces good fractions, it is particularly preferred to further process the remaining fraction using PGNAA when pre-sorting by LIBS. However, the good fractions produced using the LIBS process can also, of course, be subjected to post-sorting using PGNAA.

[0040] A further feature of the present invention provides that the characteristic components of a particular aluminum alloy are selected as the predetermined chemical composition. Specific aluminum alloys are characterized by specific individual chemical elements. Therefore, it is not necessary to analyze all alloying elements of the material components being sorted to distinguish between aluminum alloys. Therefore, identifying one alloying element may be sufficient to clearly distinguish between two aluminum alloys. This is especially true when the alloy composition contains predictable components. For example, if the scrap mixture being sorted contains only components made of two aluminum alloys, then only these two aluminum alloys are predictable. If these two predictable aluminum alloys differ in a characteristic alloying element, it is sufficient to identify the chemical composition of the component based on this alloying element.

[0041] According to a further feature of the invention, it is provided that in the element identification by PGNAA in the second stage, alloying elements from the group of zinc, copper, iron and manganese are taken into account, in particular, as these alloying elements are of particular importance from an economic point of view, and therefore it is advantageous to divide the material part stream into subfractions representing these alloying elements.

[0042] The device according to the invention is particularly used for carrying out the method according to the invention. For this purpose, the device proposed in the invention has a first analytical device and a second analytical device. The first analytical device is used for a first pre-sorting in a first process step, and the second analytical device is used for a final sorting in a second process step. The two analytical devices can be connected to each other by a conveyor system, which allows the two process steps to be carried out immediately one after the other.

[0043] The first analytical device is designed to determine predetermined material properties of the material parts and to fractionate the material parts by means of a sorting device. Predetermined material properties in the sense of the present invention can be, in particular, density, absorption capacity, and chemical composition. The first analytical device is designed accordingly, so that the material parts can be sorted according to the desired material properties.

[0044] According to a particularly preferred embodiment of the invention, the first analytical device is configured to determine the chemical composition of the material parts, in particular by testing, for each material part, whether a predetermined chemical component is a component of said material part, which testing can be carried out preferably by LIBS in the manner already described.

[0045] The first analysis device includes a sorting device for dividing the material components into two fractions, a good fraction and a residual fraction, depending on a previously performed material analysis, for example, based on the chemical composition of the material components.

[0046] The second analytical device is configured to subject the material components in one of the two fractions to PGNAA and then provide the material components into individual subfractions depending on the elemental identification results from the PGNAA. In this process, the analysis of the material components is performed in real time, thereby allowing the material components being moved in the transport stream to be immediately sorted into individual subfractions.

[0047] According to a further feature of the invention, a first analytical device is provided to enable analysis by LIBS, and for this purpose the first analytical device comprises: - a sorting unit configured to feed the material parts into one of two fractions; a laser device configured to generate a plasma on the surface of the material part by means of a laser beam propagating along a beam axis, and a spectrometer system configured to perform a spectral analysis of plasma light emitted by the laser-induced plasma and to generate an output signal corresponding to the result of the performed spectral analysis; - a control device configured to receive said output signal and to operate said sorting unit based on said output signal and on sorting criteria.

[0048] The spectrometer system includes a spectrometer and a detection unit optically connected to the spectrometer, the detection unit having an objective lens with an associated detection cone that forms a plasma detection region in an overlap region with the laser beam.

[0049] Using an analytical device thus equipped, the chemical composition of a material part can be analyzed by LIBS in a manner known per se, and the device can be set to a particular predetermined element or a predetermined alloy (e.g., an aluminum alloy).

[0050] According to a further feature of the present invention, the second analysis device comprises a transport device having a conveyor belt for transporting the material parts in a continuous transport stream, the conveyor belt serving to transfer the material parts into a transport stream of a predetermined width and height, the geometric design of which is particularly dependent on the detection unit used for the PGNAA.

[0051] According to a further feature of the present invention, the second analyzer includes a detection unit having a neutron source disposed below the conveyor belt and a detector disposed above the conveyor belt facing the neutron source. This allows for a planar scan of the conveyor stream, so that, taking into account a known conveyor speed, it is possible to calculate which length of the conveyor belt is covered with material components of a specific average chemical composition. In this way, the conveyor stream can be allocated in time to the individual subfractions, thereby allowing the conveyor stream to be easily and efficiently supplied to different subfractions separated from one another. Of course, the neutron source and detector can also be arranged in reverse.

[0052] According to a further feature of the invention, the detection unit is followed in the conveying direction of the conveyor belt by a plurality of separate compartments, each compartment serving to hold one subfraction of material parts.

[0053] Compartments are provided to divide the conveyed material into different subfractions. These compartments represent collection points for the material parts that are spatially separated from one another, one collection point being provided for each subfraction. Such collection points can be formed, for example, by boxes, containers, etc. The only important thing is that these compartments are arranged downstream of the detection unit in the conveying direction of the material parts, so that after the PGNAA has been performed, the conveyed material can be correctly assigned to the individual compartments.

[0054] According to a further feature of the invention, each compartment is assigned a circulating conveyor belt arranged vertically above said compartment. The individual compartments are arranged one behind the other in the conveying direction of the material component transport stream. Above each compartment, an individual conveyor belt is provided, which is also connected one behind the other in the conveying direction, thereby allowing the material component transport stream to be transferred from conveyor belt to conveyor belt. In this case, one conveyor belt is assigned to each compartment, allowing the transport stream to be passed from compartment to compartment by the associated conveyor belt. The design according to the invention also allows the material stream supplied to the conveyor belt to be supplied specifically to the individual compartments, depending on the conveyor belt used.

[0055] According to another aspect of the present invention, it is provided that the conveyor belts are each inclined relative to the horizontal, and thus have a first end and a second end, the two ends being located at different height levels, such that the rear end of one conveyor belt in the conveying direction extends above the front end of the conveyor belt located downstream of it in the conveying direction.

[0056] According to a further feature of the invention, the running direction of the conveyor belt can be reversed. In combination with the conveyor belt being arranged at an angle to the horizontal, the precise allocation of the conveyed material stream to the individual compartments can be ensured in a simple and effective manner. This is because the conveyor belt running in the conveying direction transfers the material stream from one conveyor belt to another and then transfers it to the conveyor belt running in the opposite direction. This conveyor belt running in the opposite direction transfers the material fed thereon to the compartment to which it belongs. When the material is to be sent to a different compartment, the running direction of the conveyor belt is reversed again. This allows the conveyor stream to be precisely distributed to the individual compartments in a technically simple and effective manner.

[0057] Further features and advantages of the present invention may become apparent from the following description taken in conjunction with the drawings. [Brief explanation of the drawings]

[0058] [Figure 1] 1 is a schematic diagram of a first analytical unit of a device according to the invention. [Figure 2] Schematic representation of a second analytical unit of a device according to the invention. [Figure 3] 1 is a schematic diagram of a device according to the invention and its principle of operation. DETAILED DESCRIPTION OF THE INVENTION

[0059] Figure 3 shows a schematic diagram of a device 1 according to the invention for analysing and sorting materials 4. The device 1 according to the invention comprises a first analytical device 2 and a second analytical device 3, which are shown in more detail in Figures 1 and 2, as will become apparent from the following description.

[0060] Figure 1 shows a schematic representation of a first analytical device 2, which is used to sort material components based on laser-induced breakdown spectroscopy (abbreviated LIBS) and assign them to two fractions F1 and F2.

[0061] 1 is configured to subject a material part 4 to laser-induced breakdown spectroscopy and to sort it depending on the results of the spectral analysis. In the example shown, two fractions F1 and F2 are provided, to which the material part 4 can be allocated. Each fraction F1 and F2 is collected at a collection point 5, for example in the form of a container.

[0062] As can be seen from the schematic diagram according to Figure 1, the analysis device 2 comprises a supply means 6 followed by a chute 9. In intended use, material parts 4 are fed to the supply means 6. The supply means 6 serves to transport the material parts 4 along a feed surface 7 provided by the supply means 6, in fact up to an upper section 8 of the chute 9, where the material parts 4 are transferred from the supply means 6 to the chute 9.

[0063] The supply means 6 serves in particular to separate / individualize the material parts 4 fed onto the supply means 6, so that these material parts 4 can be fed to the chute 9 at intervals from one another.

[0064] The material parts 4 transferred to the chute 9 slide down the chute 9 under gravity to the lower edge 10 of the chute 9, which is designed opposite the upper section 8 of the chute 9. The chute 9 is specifically designed to align the material parts 4 and transfer them to a predetermined falling path. After leaving the chute, the material parts 4 continue to fall under gravity in the ambient atmosphere. As they do so, they pass through a spectrometer system 11, which ensures their analysis. The spectrometer system 11 generates an output signal based on the results of the spectral analysis. This signal is supplied to a control device 12, which operates, i.e., controls, a sorting unit 13 depending on the output signal and stored sorting criteria. The sorting unit 13 either deflects or does not deflect the material parts 4 during free fall. If not deflected, the material parts 4 reach a collection point 5 for fraction F2. Otherwise, ie if sorting by the sorting unit 13 takes place, the material part 4 arrives at the collection point 5 for fraction F1.

[0065] Spectrometer system 11, which is part of LIBS module 14, is used to analyze the composition of material component 4. LIBS module 14 also includes laser device 15 and control device 12. Preferably, laser device 15, spectrometer system 11, and control device 12 are housed in a common housing, which is not shown in detail in FIG.

[0066] The laser device 15 comprises further individual components such as a laser beam source, an optical fiber, and collection optics. The spectrometer system 11 also includes a detection unit, which provides several objective lenses. A detection cone 16 is assigned to each of these objective lenses, which form a plasma detection area 18 in the overlapping area with a laser beam 17 emitted by the laser device 15. These plasma detection areas 18 are arranged offset from one another along the beam axis of the laser beam 17 and together form the field of view of the detection unit. The field of view is thus made up of the individual plasma detection areas, which determines the detection area covered by the detection unit as a whole.

[0067] As soon as the material part 4 passes through the detection region, it is irradiated with a laser beam and a laser-induced plasma is formed on the surface of the material part 4. This is analyzed in the manner already described by the spectrometer system 11 and, depending on the analysis result, the material part 4 is deflected by the sorting unit 13. In particular, the sorting unit 13 can be equipped with an air nozzle which, when pressurized, allows the material part 4 to be sorted.

[0068] FIG. 2 shows a schematic diagram of a second analytical unit 3 of a device 1 according to the invention. In the illustrated example, the second analytical device 3 serves to post-sort the material components 4 of the first fraction F1 stored in the bunker 20. Such post-sorting can also be performed on the material components 4 of the second fraction F2.

[0069] By means of the second analysis device 3, the material parts 4 are transferred into subfractions, with a separate compartment 29 (e.g., in the form of a container) being provided for each subfraction. In the illustrated example, a total of eight subfractions are provided, namely subfractions A1, A2, B1, B2, B3, B4, C1, and C2. Subfractions A1 and A2 have a first alloying element in common, but may differ with respect to the second alloying element. The same applies to the other subfractions, with the subfractions of group B differing with respect to four possible further alloying elements.

[0070] A conveying device 23 having 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.

[0071] A conveying device 23 is used to transfer the material parts 4 from the bunker 20 into a continuous conveying stream, which is then subjected to PGNAA. The conveying stream is then directed into individual subfractions A1 to C2 depending on the elemental identification results obtained by PGNAA.

[0072] The first conveyor belt 21 in the conveying direction is equipped with a belt scale 22. The belt scale 22 is used to determine the total weight of the material parts 4 fed onto the first conveyor belt 21, so that the speed of the conveyor belt 21 can be adjusted accordingly in order to homogenize the conveying stream.

[0073] The transport stream is transferred from the first conveyor belt 21 to a second conveyor belt 24. A detection unit 26 for carrying out the PGNAA is arranged here. For this purpose, the detection unit 26 has a neutron source 27 and a detector 28 arranged opposite the neutron source 27. In a manner known per se, the result of the PGNAA provides an elemental identification result corresponding to the chemical composition of the material part 4.

[0074] The analyzed material parts 4 are then transferred to a further conveyor belt 25, which is followed in the conveying direction by a further conveyor belt 30. One conveyor belt is assigned to each compartment 29. For example, the first conveyor belt 30 in the conveying direction is assigned to sub-fraction A1, the second conveyor belt 30 in the conveying direction is assigned to sub-fraction A2, and so on.

[0075] The conveyor belt 30 is designed so that its direction of travel is reversible, i.e., it can run clockwise or counterclockwise. By reversing the direction of travel of the individual conveyor belts 30, it is possible to selectively feed the conveyed material to individual compartments 29 and thus to individual sub-fractions.

[0076] When all conveyor belts 30 are running clockwise, the material to be conveyed is transferred from conveyor belt 30 to conveyor belt 30 until it reaches the last conveyor belt 30 in the conveying direction, from where it falls into compartment 29 of subfraction C2.

[0077] When the direction of circulation of one of the conveyor belts 30 is reversed, the material fed to this conveyor belt 30 is no longer conveyed in the conveying direction, but is conveyed in the opposite direction and is therefore transferred to the compartments 29 assigned to this conveyor belt 30. Thus, the change in the running direction of the conveyor belt 30 can be used to selectively assign volumetric flow rates to the individual compartments 29.

[0078] The change in the running direction of the conveyor belt 30 is timed to be dependent on the conveying speed. For example, if the detector unit 26 detects a particular average chemical composition of the conveying stream over a period of, say, 10 seconds, the subfraction associated with this average chemical composition can be determined and then the time it takes for the detected portion of the conveying stream to reach the associated conveyor belt 30 can be calculated. Furthermore, it can be calculated how long it takes for the detected section of the conveying stream to reach the associated conveyor belt 30 and how long the conveyor belt 30 needs to be operated in the reverse direction so that the previously detected section of the conveying stream can be delivered to the corresponding compartment 29.

[0079] Finally, Figure 3 shows the configuration of the device according to the invention. As can be seen from this figure by way of example, both material components of fractions F1 and F2 coming from the first analytical device 2 are each post-sorted by a second analytical device 3. For this purpose, a conveyor belt 19 is provided, which delivers fractions F1 and F2 to respective bunkers 20, from where the post-sorting then takes place in accordance with the explanation given in connection with Figure 2. Figure 2 shows the second analytical device 3 in a schematic side view, while Figure 3 shows a schematic view from above.

[0080] List of Reference Numbers 1 device 2. First analytical device 3 Second analytical device 4 Material parts 5 Collection Points 6 Supply means 7 Supply side 8 Upper Section 9 Shoot 10 Lower edge 11 Spectrometer System 12 Control Devices 13 Sorting Unit 14 LIBS Module 15 Laser Devices 16 detection cone 17 Laser Beam 18 Plasma detection area 19 Conveyor Belt 20 Bunker 21 Conveyor Belt 22 Belt Scale 23 Transport Device 24 Conveyor Belt 25 Conveyor Belt 26 Detection Unit 27 Source 28 detectors 29 compartments 30 Conveyor Belt F1 / F2 fraction A1-C2 subfractions.

Claims

1. 1. A method for analyzing and sorting a plurality of material parts, in particular scrap parts made of aluminum, carried out in two stages: Pre-sorting is performed in the first stage, and post-sorting is performed in the second stage; In a first step of the first stage, predetermined material properties of the material part (4) are identified by an analysis device (2), and in a second step of the first stage, the material part (4) is supplied to either one of two fractions, i.e., a first fraction (F1) or a second fraction (F2), depending on the identified material properties; In a first step of the second stage, the material part (4) of one of the two fractions (F1), (F2) is transferred to 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 supplied to individual subfractions (A1 to C2) depending on the element identification results obtained by the PGNAA.

2. 10. The method of claim 1, wherein the two steps are performed in immediate succession.

3. 3. The method according to claim 1 or 2, wherein the material parts (4) of the two fractions (F1, F2) are each subjected to PGNAA.

4. The method according to any one of claims 1 to 3, wherein the predetermined material properties of the plurality of material parts (4) are selected to be at least one of their respective density, absorbency, chemical composition, etc.

5. 5. The method according to claim 4, wherein in the first step of the first stage, the chemical composition of each of the plurality of material parts (4) is identified by inspecting for each material part (4) whether a predetermined chemical component is a component of the material part (4), and wherein in the second step of the first stage, each of the plurality of material parts (4) is supplied to either the first fraction (F1) or the second fraction (F2) depending on the presence of the predetermined chemical component as a component of the material part (4).

6. 6. The method according to claim 5, wherein the determination of the chemical composition of the material part (4) in the first stage is performed by LIBS.

7. 7. The method of claim 5 or 6, wherein the characteristic components of a particular aluminum alloy are selected as the predetermined chemical composition.

8. 8. The method according to claim 5, wherein in the second step, when identifying the elements using PGNAA, in particular alloying elements from the group Zn, Cu, Fe and Mn are taken into account.

9. A device for analyzing and sorting a plurality of material parts, in particular scrap parts made of aluminum, comprising a first analysis device (2) and a second analysis device (3), the first analysis device (2) is configured to identify predetermined material properties of the material part (4) and to feed the material part (4) into one of two fractions (F1, F2) by a sorting device (12); The second analytical device (3) is configured to subject the material part (4) of one of the two fractions (F1, F2) to PGNAA and to supply the material part (4) to individual subfractions (A1 to C2) depending on the element identification results by the PGNAA.

10. 10. The device according to claim 9, wherein the first analytical device (2) is configured to determine the chemical composition of the plurality of material components (4) by testing, for each material component (4), whether a predetermined chemical component is a component of the material component (4).

11. The first analytical device (2) comprises: a sorting unit (13) adapted to feed said material parts (4) into one of two fractions; a laser device (15) configured to generate a plasma on the surface of said material part (4) by means of a laser beam (17) propagating along a beam axis; a spectrometer system (11) configured to perform a spectral analysis of the plasma light emitted by said laser-induced plasma and to generate an output signal corresponding to the result of said spectral analysis performed; - a control device (12) configured to receive said output signal and to operate said sorting unit (13) based on said output signal and on sorting criteria.

12. 12. The device according to claim 9, wherein the second analysis device (3) comprises a detection unit (26) having a neutron source (27) and a detector (28) facing the neutron source (27), or having only a detector (28), the detector (28) being arranged above, below or to the side of the conveyor belt (24).

13. 13. The device according to any one of claims 9 to 12, wherein a plurality of compartments (29) spaced apart from one another in the conveying direction of the conveying device (23) are arranged downstream of the detection unit (26), each of the compartments (29) serving to receive material parts (4) of subfractions (A1 to C2).

14. 14. A device according to claim 13, wherein each compartment (29) is assigned a circulating conveyor belt (30) arranged vertically above said compartment (29).

15. 15. The device according to claim 14, wherein the direction of travel of the conveyor belt (30) is reversible.

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