Waste or retired battery treatment plants and processes

Abstract

A used and / or retired battery processing plant and process wherein a plurality of objects nominally including lead acid batteries and batteries and objects of different types originating from a separate waste collection of used and / or retired batteries are subjected to X-ray scanning. If the X-ray scan analysis indicates that the object is not a lead acid battery, in particular a lithium ion battery or battery, it is diverted from a processing flow including grinding the object and separating the lead from other materials.

Description

Technical Field

[0001] The present invention relates to a battery treatment plant and process for waste or retired batteries, and in particular to a battery treatment plant and process for recovering the lead contained in lead-acid batteries. Background Art

[0002] Lead-acid batteries have been known for almost two centuries but are still widely used due to their low cost, especially in the automotive industry to allow starting of hot engines and to power all on-board electrical utilities. For several other uses, especially powering portable electronic components such as mobile phones, computers, music players, etc., instead, power sources and batteries based on different materials and electrochemical reactions, especially lithium-ion (Li-Ion) batteries and accumulators, are now more prevalent.

[0003] At the end of their useful life, lead-acid batteries go through a recycling process in order to recover the materials forming their different components. Conventional lead-acid battery recycling processes provide for the grinding of spent batteries and the subsequent separation of the ground parts into homogeneous material portions. Used or decommissioned lead-acid batteries are often collected together with different types of cells and accumulators, which are not always immediately visually distinguishable. In particular, the appearance of automotive lead-acid batteries is often confusingly completely similar to that of lithium-ion batteries, also because they have to fit into compartments of standard sizes. Although the weight of lead-acid batteries is significantly higher than that of lithium-ion batteries of the same size, the initial sorting performed by the operator is not error-proof.

[0004] The solvents used in lithium-ion batteries can be flammable in some cases; moreover, this type of battery retains a considerable amount of charge even after decommissioning, and a short circuit between the electrodes can cause an explosion. Therefore, when lithium-ion batteries enter a plant for the treatment of used or retired lead-acid batteries, there is a high risk of explosion, especially during the initial grinding phase, when their electrodes are more likely to be short-circuited; in fact, mills are equipped with suitable protective shields to contain small explosions that occur in them. In addition to the risk of damage to the facility due to explosions, there is also an associated risk of injury to the operating personnel, as well as chemical risks due to the inhalation of hazardous substances generated during explosions or due to increased temperatures, mainly from lithium and lead (but also from other substances that make up the batteries being treated). Summary of the invention

[0005] The technical problem underlying the present invention is therefore to overcome the above-mentioned disadvantages, in particular by providing a plant and a process for the treatment of used or retired batteries having greater safety, in particular reducing the probability that lead-free batteries will reach a mill for grinding used or retired batteries, thereby reducing the risk of explosion.

[0006] In a first aspect of the invention, the invention relates to a plant for the treatment of used and / or retired batteries according to claim 1 .

[0007] In a second aspect of the invention, the invention relates to a process according to claim 7 for treating spent and / or retired batteries.

[0008] The applicant surprisingly realized that despite the known radiation absorption properties of lead, given that lead is conventionally used as a shielding element in radiography, X-ray analysis of objects with a high lead content still makes it possible to identify those objects and distinguish them from objects containing metals and possibly other materials than lead. Therefore, only lead-acid batteries are forwarded to the mill to grind them, while lithium-ion cells and batteries, or other types containing explosive or hazardous elements, or in any case representing impurities relative to the lead recycled from the factory, are not forwarded.

[0009] Preferred features of the plant and process of the invention are set out in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other features and advantages of the present invention will become more apparent from the following detailed description of some preferred embodiments of the present invention with reference to the accompanying drawings, in which:

[0011] Figure 1 is a block diagram related to a waste and / or retired battery treatment plant according to the present invention,

[0012] Figure 2 is a block diagram related to the components of the factory,

[0013] Figure 3 yes Figure 1 A schematic diagram of a part of an embodiment of a plant,

[0014] Figure 4 yes Figure 3 A cross-sectional view of the testing location of the factory,

[0015] Figure 5-7 is a diagrammatic representation of another embodiment of an X-ray detector of a plant according to the present invention,

[0016] Figure 8 is a flow chart of a process for treating used and / or retired batteries according to the present invention, and

[0017] Fig. 9 yes Figure 8 A flowchart of a portion of an embodiment of a process. DETAILED DESCRIPTION

[0018] exist Figure 1In FIG. 1 , a block diagram of a plant 1 for processing used and / or retired lead-acid batteries according to the invention is shown. The plant 1 comprises a sorting device 2 , a mill 3 and at least one separator stage 4 .

[0019] Input material 5 originating from a separate waste collection of used and / or retired batteries is input, for example in batches, to the sorting device 2. This material should nominally contain only lead-acid batteries, but may include batteries other than lead-acid batteries, other undesirable equipment or various objects, which material may optionally be subjected to a preliminary sorting step performed by an operator.

[0020] In the sorting device 2, such batteries, such other devices or such various objects other than lead-acid batteries (if provided, which then bypass the preliminary sorting) are largely diverted from the main work flow as waste 6 in a manner better described below, so that they do not enter the mill 3. The scrap material 6 can be inspected downstream by the operating personnel, during which any lead-acid batteries erroneously rejected by the sorting device 2 can be recovered and reinserted into the input material 5 (according to Figure 1 Path not shown in the figure).

[0021] The part of the input material 5 that is not diverted as waste product 6 is fed to the mill 3 as material to be ground 7 .

[0022] The ground material 8 output from the mill 3 is forwarded to the above-mentioned one or more separator stages 4, which are generally of the hydrostatic and / or hydrodynamic type, which separate the ground material 8 into preferably homogeneous material portions, referenced as a whole by reference numeral 9, one of which consists of the so-called paste, i.e. the battery active material on which the charging and discharging processes take place during use. The other portions generally include a polymeric material portion originating from the battery casing; a polymeric material portion originating from the battery separator; a metallic portion consisting of the material forming the grid (electrode) and the battery electrodes. It will be appreciated by those skilled in the art that the plant 1 has been greatly simplified compared to a real plant and that there may be several components and material flows in addition to those shown, including a dilution stream, a recirculation stream, mechanical treatment equipment and chemical treatment equipment for various portions.

[0023] refer to Figure 2 , the sorting device 2 according to the invention comprises an X-ray detector operating at a detection position 11, which is configured to temporarily accommodate at least a part of at least one object A. Object A is ideally a lead-acid battery, but non-ideally it may be another type of battery, equipment or other object found in the input material 5 originating from a separate waste collection of used and / or retired batteries.

[0024] The X-ray detector 10 comprises at least one X-ray source 12 configured to emit a radiation beam, and at least one array 13 of X-ray detection elements arranged at predetermined positions within the path of the radiation beam emitted by the source 12, which passes through the detection position 11 and thus each time passes through the object A contained therein. For the sake of simplicity, the reference A is used herein both for a single object and for the object as a whole.

[0025] It is well known that the radiation emitted by source 12 is attenuated by absorption along its path inside object A following an exponential law; the attenuation coefficient depends, in addition to the energy of the beam emitted by source 12, on the thickness of the material and, most importantly for the purposes of this article, on the chemical composition of object A, in particular the atomic number (Z) of the constituent elements. The intensity of the radiation detected by each individually addressable detection element or pixel of array 13 varies accordingly according to the magnitude of these characteristics.

[0026] Advantageously, it is possible to make the grayscale values ​​or the values ​​of a pseudo-color scale in the range explained below correspond to the readings of the pixels of the array - this makes it possible to reconstruct a two-dimensional image by combining subsequent readings over time, with the gray tones (or pseudo-colors) representing the constituent materials and the relevant thicknesses in a cross section of the object through, or a qualitative average in the case of inhomogeneous materials, or even to reconstruct a three-dimensional image of the object.

[0027] The radiation beam emitted by the source 12 is preferably fan-shaped and has a size in a first direction X that is sufficient to pass through the entire detection position 11, for example a size of about 70°-90°, preferably a size of about 80°. The size of the radiation beam in a second direction Y orthogonal to the first direction is preferably very small, for example less than 6°, preferably less than about 3°, so that the radiation beam extends substantially in a plane and generates a substantially one-dimensional scan line extending generally along the direction X at the detection element array 13.

[0028] The scanning plane defines a cross-sectional plane of the object A. The relative movement between the object A and the X-ray detector 10 in said second direction Y causes the radiation beam to scan the entire detection position 11 and thus the entire object A or a part thereof contained therein to pass cross-sectionally.

[0029] The reading of the array of detection elements 13 is performed periodically during the relative movement between the X-ray detector 10 and the object A, and a predetermined number N of consecutive readings are suitably stored as a current image 14. In the present description and the appended claims, the term "image" is used broadly to cover a general representation of the characteristic features present in the above-mentioned detection position 11 (the chemical composition of the object A, in particular the atomic number Z of the constituent elements, and the thickness of the material), not necessarily a graphical representation.

[0030] A person skilled in the art will readily understand that the number N of consecutive reads (size of the memory containing the current image 14) defines the size of the object observation window along the direction Y - in broad terms corresponding to the size of the detection position 11 mentioned above; and that the storage means are preferably of shift type or FIFO ("first in, first out"), at least from a logical point of view. Thus, the current image 14 changes over time in terms of its information content, and each valid cross section on the object A (or several arrays of objects A) remains available only for a certain period of time in the memory containing the current image 14. Depending on the readout speed of the array 13 and the storage speed, the relative speed between the X-ray detector 10 and the object A may be comprised, for example, between about 0.2 m / s and about 0.4 m / s.

[0031] The current image 14 is transmitted to a processor 15 which provides for comparing the information contained therein with one or more threshold data 16 and / or with the content of a database of sample images 17 , as described in more detail below.

[0032] Optionally, the processor 15 can also provide the current image 14 and / or said threshold data 16 and / or a sample image 17 of said database to a workstation 18 intended for an operator P, in original form or, preferably, in a derived form that can be appreciated more immediately by the operator P (in particular in the form of a gray tone or false color image, and a corresponding legend for gray tone / false color), as well as possible results of the processing performed by the processor 15 based on the input provided to the processor 15 itself.

[0033] The processor 15 and / or the operator P, via the workstation 18, if provided, issues a sorting signal 19. In the present description and the appended claims, the term "signal" is to be understood in its broadest possible sense, indicating "any form of matter or energy capable of transmitting information carrying it", wherein the information carried by the sorting signal 19 comprises at least an indication of whether at least one object other than a lead-acid battery is present in the detection location 11 and whether it must therefore be diverted as a scrap 6 and should not reach the mill 3 of the plant 1.

[0034] The sorting signal 19 may be processed by one or more utilities 20, for example, which are intended to stop the relative movement between the X-ray detector 10 and the object A, to give an audible and / or visual alarm to the operator P or operators present in the vicinity of the detection position 11 and / or to automatically eject the object at the detection position 11 when the current image 14 has been acquired. The automatic ejection may be performed, for example, by an anthropomorphic robot, by a drop door of the object A, by a deflector that can be selectively placed in the path of the object A, and otherwise by a piston pusher that selectively acts in a direction orthogonal to (or more generally at a given angle to) the direction of relative movement between the X-ray detector 10 and the object A.

[0035] In order to increase the reliability of the sorting device 2, the processor 15 can be connected to the same or compatible remote system S via a network R (which can be, for example, the Internet), and is configured to receive additional and / or updated sample images and / or threshold data from the remote system S, and can transmit its own sample images and / or its own threshold data to the remote system S.

[0036] Whether or not it is connected in the network R, the processor 15 preferably has artificial intelligence, in particular it is capable of learning to improve the decision process and thus enhance the reliability of the sorting device 2. The processor 15 is preferably of the neural network type.

[0037] exist Figure 3 and Figure 4 In FIG. 8 , an exemplary embodiment of a part of a plant 1 is shown, including in particular a sorting device 2 and a mill 3 .

[0038] In this case, the sorting device 2 includes a conveyor belt 31, such as a closed-loop mat conveyor belt or a segmented conveyor belt, which performs the above-mentioned relative movement between the X-ray detector 10 and the object A. The conveying direction of the conveyor belt 31 is the direction Y, and the direction transverse to the conveyor belt is the scanning direction X ( Figure 4 ).

[0039] The conveyor belt 31 advantageously also serves as a feeder for the mill 3 and is generally ascending, suspended on feet 32 ​​a , 32 b , 32 c of increasing height moving towards the mouth 33 of the mill 3 .

[0040] The conveyor belt 31 is preferably inserted into or forms the bottom of a metal tunnel 34 which is connected at its downstream end (with respect to the conveying direction) to the mill mouth 33, completely and tightly closing it.

[0041] An extraction system, whose extraction fan 35 is schematically shown, is provided to generate negative pressure at the mill 3 and the tunnel 34. The negative pressure prevents the electrolyte from forming harmful acid mist inside the mill 3 during the crushing of the lead-acid batteries, which spreads into the environment, thereby safeguarding the health of the operators of the plant 1. The fan 35 is shown on top of the mill 3, but it can be located at other locations along the conveyor belt 31.

[0042] The X-ray detector 10 and the detection location 11 are preferably embedded within the tunnel 34 , at a location of the tunnel 34 spaced upstream (with respect to the conveying direction) of the mouth 33 of the mill 3 .

[0043] At the test position 11, the tunnel 34 is provided with a lead shield 36 and a lead inspection cover 37, which closes the access to the test chamber 38. Figure 4In the present specification and the appended claims, the term "leaded" indicates a process that allows shielding of X-rays. An inspection platform 39 that can be reached by a ladder 40 (eg, a cage ladder) can be made around the leaded inspection cover 37.

[0044] Between the detection position 11 and the mouth 33, i.e. downstream of the detection position 11, there is an ejection device 41. An ejection door 42 is formed laterally in the tunnel 34. The door 42 can be resealed in a sufficiently tight manner (e.g. by overlapping rubber strip curtains 43) by the negative pressure generated by the suction fan 35.

[0045] The piston pusher 44 may be retracted on the side of the tunnel 34 opposite the gate 42 and may extend along the entire width of the conveyor belt 31 in the direction X. When the sorting signal 19 indicates the presence of at least one object other than a lead-acid battery, the pusher is selectively actuated to push the object out of the gate 42. Undesirably, any lead-acid battery that is particularly close to the undesirable object may also be pushed and may be recovered as described above.

[0046] A waste container 45 is shown below the side door 42, but it may be missing or replaced by, for example, a second conveyor belt. Advantageously, a slow second conveyor belt may allow the objects A to be further spaced apart before they are re-entered onto the main conveyor belt 31 upstream of the detection position 11, thereby increasing the reliability of sorting.

[0047] Suitable X-ray sources 12 include, for example, X-ray tubes with a nominal voltage of, for example, 200 kV or 150 kV, whose focal spot preferably has a size of 0.8 mm, as measured according to standard EN 12543. The X-ray tube preferably has a tungsten anode. The X-ray tube is preferably provided with an internal power supply, a safety circuit against overheating, an oil and / or forced air cooling system and / or a high-frequency voltage multiplier.

[0048] As from Figure 4 As can be seen better in FIG. 1 , the X-ray tube 12a of the source 12 of the X-ray detector 10 is housed in a suitable seat in a support 46. The support 46 has a directional radiation cavity 47 which is open on one side at the output window of the source 12 and on the other side at the face of the support 46 facing the conveyor belt 31. The directional radiation cavity 47 is Figure 4 The cross section of the ferrule is frustoconical and defines the width of the fan-shaped radiation beam 48. If the support 46 is not made of lead or a lead-containing material, the directional radiation cavity 47 is preferably provided with a lead-containing coating to retain radiation that is difficult to capture.

[0049] The array 13 of X-ray detection elements preferably comprises a plurality of plates 49, each plate comprising a linear detector device having a certain number of individually addressable detection elements or pixels. For example, there may be seventeen plates 49, each plate being provided with a 64-pixel linear detector device, for a total of 1088 pixels per scan line. The array 13 of X-ray detection elements is preferably of the CCD type. In addition, there may be one or more electronic components (not shown) for controlling the acquisition of data from each plate 49 and for managing the transmission of the acquired data to the processor 15.

[0050] All detectors of the array 13 (ie all panels 49) are suitably fixed to support bars 50 ( Figure 3 ), which ensures that they are perfectly aligned with each other and facilitates the alignment operation of the output window of the cavity 47 relative to the source 12 and the support 46.

[0051] The support strip 50 is preferably curved, and the plate 49 with the array 13 of detection elements is supported on its concave surface. This arrangement is advantageous, on the one hand, because the distances of the various detection elements from the source 12 vary less than if the array were flat; on the other hand, this arrangement is more suitable for the top conveying surface of the conveyor belt 31, which is also generally concave, so as to better hold the objects A laterally.

[0052] In any case, the processor 15 may be configured to appropriately take into account the distance of each pixel from the source 12 , and / or the mutual inclination between the propagation directions of the X-rays detected by each pixel of the array 13 , during formation of the current image 14 .

[0053] It will be appreciated that the conveyor belt 31 must have suitable characteristics of being transparent to X-rays or having low absorption of X-rays due to the positioning of the array 13 of detection elements described above below the conveyor belt 31. Suitable materials for the conveyor belt 31 include rubber layers of different compounds glued together with a mesh of plastic material inserted to increase the mechanical resistance in the longitudinal direction.

[0054] The X-ray detector 10 may be Figure 4 , in order to provide more accurate information in the current image 14. A second X-ray source, or even more than one X-ray source, may be provided, associated with the same detection element array or with a corresponding detection element array and / or a dual sensitivity detection element array, and / or a dual emission source may be provided, as better disclosed below.

[0055] exist Figure 5-7 Some configurations are shown in the Figures by way of non-limiting examples only. In those Figures, for simplicity, the arrays of detection elements are represented as rectangles, but it should be understood that they can extend along curves as described above. The direction of the main dimension of the array is called the scanning direction.

[0056] exist Figure 5 In the configuration schematically shown in FIG. 1 , there is a second source 51 and an associated second array of detection elements 53; the two sources 12, 51 and the two arrays 13, 53 are arranged side by side in the Y direction of relative movement between the object A and the X-ray detector, respectively. The X-rays emitted by the second source 51 form a radiation beam 52, whose average propagation direction 52a is substantially parallel to the average propagation direction 48a of the radiation beam 48 emitted by the source 12, the two average propagation directions 48a, 52a extending along the direction Z, but their energy is different from that of the X-rays emitted by the source 12. Since the attenuation of the two beams with different energies is different for each material, by combining the information of the second array of detection elements 53 with the information of the array of detection elements 13, more detailed information about the material composition in the cross section of the object A scanned at each time can be obtained, so that the materials can be better distinguished and therefore a more accurate sorting signal 19 can be emitted. In particular, in this case, a false-color current image 14 can also be obtained, which is more directly appreciated by the operator P.

[0057] In an alternative configuration not shown, two sources 12, 51 emitting X-rays of different energies may be configured to emit non-parallel beams 48 and 52 that converge onto a single array of detection elements 13 capable of detecting double exposures. In yet another configuration not shown, a single dual exposure ("dual energy") source associated with a single array of dual exposure detection elements 13 may be used.

[0058] exist Figure 6 In the configuration schematically shown in , the X-rays emitted by the second source 54 instead form a radiation beam 55, the average propagation direction 55a of which (extending along the direction X) is substantially orthogonal to the average propagation direction 48a of the radiation beam 48 emitted by the source 12, and which may have the same energy as the X-rays emitted by the source 12; the second source 54 is associated with a second array 56 of detection elements, which has a scanning direction along the direction Z, which is a vertical direction extending in the height direction above the conveyor belt 31, and therefore the thickness direction of the scanning section. This configuration allows the individualization of unwanted objects, which are completely hidden in the field of view of the main pair of source 12 and array 13 by the larger size of the lead-acid batteries and the overlap of the lead-acid batteries along the Z direction.

[0059] In another configuration, in addition to the source 12, there may be a Figure 5 The additional source of source 51 is arranged as Figure 6 An additional source 54 of the source 12 has corresponding arrays of detection elements 53, 56, or a single additional array 56 when the array 13 is associated with both sources 12 and 51.

[0060] Similar to the reference above Figure 5In the manner described, also for the scanning along the direction Z, more accurate information can be obtained by using radiation with different energies, by providing a source 54 with double exposure and a sensor 56 with double sensitivity, or by providing an additional source (not shown) emitting a beam converging onto the same sensor 56 as the beam 55, with an energy different from that of the source 54, or by providing another additional source (not shown) and a corresponding array of detection elements (not shown) forming a radiation beam with an average propagation direction substantially parallel to the average propagation direction 55a of the radiation beam 55 emitted by the source 54, with an energy different from that of the source 54. When there are additional sources for both the scanning directions X and Z, they preferably have the same energy.

[0061] The above-mentioned various configurations can be combined as needed. As an example only, another configuration of the X-ray detector 10 may provide only a single exposure source 12 for scanning along the X direction, and conversely provide a dual exposure source or two sources for scanning along the Z direction.

[0062] exist Figure 7 In the configuration schematically shown in , the X-rays emitted by the source 12 form a radiation beam 58 still emitted in the plane XZ, but with an average propagation direction 58a inclined and preferably at 45° with respect to the thickness direction Z of the object A; the source 12 is associated not only with an array of detection elements 13, but also with a second array of detection elements 57 having a scanning direction Z. It should be understood that the two arrays 13, 57 of detection elements can also be combined into a single folded or bent array of detection elements. Also in the case of this configuration allowing undesired objects to be individualized (these objects overlap with a lead-acid battery of larger dimensions along the direction Z), the above-described variants (using double emission, possibly with a double exposure array, or using a second source) can be applied to obtain more information.

[0063] In a further configuration of the X-ray detector 10 not shown, the source 12 and any second and additional sources may be arranged in a lower position, possibly below the conveyor belt 31 , and the array of detection elements 13 in an upper position, above the height of the object A.

[0064] It should be understood that in the various embodiments described above, the processor 15 can appropriately combine the information read by the various detection element arrays. It should be understood by those skilled in the art that additional source arrays of one or more detection element pairs can also be provided (even with a shared detection element array) with still different energies and / or acting on cross-sectional planes formed at different angles to the plane of the main pair formed by the source 12 and the detection element array 13.

[0065] refer to Figure 8, the process 100 for treating used and / or retired batteries according to the present invention comprises the following steps. The process disclosed below is also illustrative of the operation of the plant 1 disclosed above.

[0066] In step 101 , a plurality of objects A originating from a separate waste collection of used and / or retired batteries are fed to a processing plant, such as the plant 1 described above; said objects A nominally comprising lead-acid batteries, but also comprising batteries and objects of different types.

[0067] In step 102, the plurality of objects A are scanned by X-rays.

[0068] In step 103, the X-ray scan is analyzed to see whether it indicates that object A is not a lead-acid battery.

[0069] As shown in decision box 104, if the analysis result of step 103 indicates that object A is not a lead-acid battery (affirmative result of the check in box 104), then step 105 is executed to deviate the processing operation sequence of object A, for example, input it into the waste stream 6 of factory 1.

[0070] If, on the other hand, the analysis result of step 103 indicates that object A is a lead-acid battery (negative result of the check of box 104), then object A remains in the processing operation sequence and is forwarded to subsequent processing steps, which typically include step 106, in which object A that was not deviated in step 105 is ground, and subsequently step 107, in which the lead is separated from other materials.

[0071] For simplicity, step 103 and subsequent steps are shown as a single occurrence in the flowchart, but it should be understood that the inspection is performed for each object A visible in the X-ray scan.

[0072] The process 100 is preferably performed continuously in a factory, such as the factory 1 described above, which is provided with a conveyor belt 31 .

[0073] Regardless of whether it is performed continuously, the analysis step 103 and the decision process of box 104 can occur in an automatic manner, in a manual manner (i.e. controlled by an operator) or in a semi-automatic manner. The process can advantageously be performed manually or semi-automatically in a preliminary step of calibration and / or learning (preferably based on sample batteries of various known types), and then in an automatic manner.

[0074] refer to Fig. 9 To gain a clearer understanding of the various options and possibilities listed above, Fig. 9 is a flow chart of an exemplary embodiment of steps 101 - 105 of the process, which is described with reference to the specific plant 1 described above, by way of example only.

[0075] In step 201 , an object A is placed on the moving conveyor belt 31 upstream of a detection position 11 through which the path of the conveyor belt 31 passes.

[0076] In step 202, a current image 14 of the detection location 11 in a time interval is acquired by X-ray scanning, representing one or more objects A or parts thereof.

[0077] In particular, the acquisition step 202 is preferably performed by subsequent linear scanning, which, as shown, comprises irradiating 203 the detection location 11 with X-rays and detecting 204 the radiation after passing through any object A present in the detection location 11 during a time interval.

[0078] In step 205 , as better discussed below, the current image 14 is analyzed to check whether during the time interval at least a portion of at least one object A of a different type than the lead-acid battery present in the detection location 11 is present therein.

[0079] As indicated by decision block 206, in the negative case no action is taken.

[0080] In the affirmative, an alarm is optionally issued in step 207; in this regard, see the previous discussion of the sorting signal 19 issued by the plant 1. In step 208, the conveyor belt 31 is stopped. In the case of automatic operating mode, as checked in box 209, the object is ejected in step 210 and the conveyor belt 31 is restarted in step 211.

[0081] In case of a non-automatic operating mode, exit NO from box 209 and in step 212 the current image 14 is analyzed by the operator P, for example by displaying it on a display of the workstation 18. The current image 14 may have been previously processed to enhance its information carrying capacity, for example by applying unsharp masking, tools for magnification, rotation, energy stripping (displaying individual element families or combinations of element families), etc.

[0082] Then, in step 213, the input of the operator P is received and evaluated. If the operator P has indicated that, in his / her opinion, at least a part of at least one object A of a different type than a lead-acid battery is represented in the current image 14, then step 210 and the subsequent step 211 are continued; otherwise, step 211 is directly executed.

[0083] In both cases, after executing step 211 , or when the check in block 206 is negative, a return is made to executing step 202 in which a new current image 14 is acquired.

[0084] It should be understood that in actual use, subsequent current images 14 may partially overlap in terms of information content, i.e. the same scan line (and therefore a cross section across the same object) may be contained in a plurality of subsequent current images 14; vice versa, if the subsequent current images 14 analyzed in step 205 are formed by all different scan lines, then two (or more) different parts of the same object A may be present in two (or more) subsequent current images 14. The process (and in particular the processor 15 implementing the process) will appropriately take this into account, i.e. if necessary, provide a buffer memory for a plurality of subsequent current images 14 and / or the possibility of conveying the object A later, reversing the direction of movement of the conveyor belt 31 after executing the steps 208, 211 of stopping and restarting the conveyor belt 31. For simplicity, the buffer memory is not included in the Figure 2 is shown in the block diagram.

[0085] Furthermore, it may happen in step 210 that, in addition to object A, other objects are ejected which were in the detection position 11 during the time interval (and which in the meantime have moved forward a certain length, up to the ejection device 41); then, as described above, a second step (not shown) can advantageously be carried out to sort the waste flow 6 and / or to reintroduce the objects onto the conveyor belt 31.

[0086] As far as the current image 14 is concerned, its processing by the processor 15 in steps 103, 104, 205, 206 and any interpretation of the same current image 14 or its derivative representation by the operator P (see steps 212, 213) require the following attention, wherein the implementation details are within the skill of a person skilled in the art. As mentioned, the current image 14 is a representation of the relative thickness at various points of the constituent materials and each object portion passing through, or a qualitative average value in the case of inhomogeneous materials, in any suitable format and preferably in gray tones or in false colors. In more detail, if each detected object is a homogeneous plate of pure chemical elements, then the thickness of the various plates is equal, which will allow the different chemical elements to be distinguished with certainty, for example from the gray tones or from the colors of the corresponding images. In the case of concern herein, the various devices and objects present in the material of the separate waste collection of lead-acid batteries as well as lithium-ion batteries, other batteries, and used and / or retired batteries are obviously objects of different sizes and heterogeneous materials.

[0087] However, the applicant has recognised that the image of the lead-acid batteries which are desired to be forwarded to the mill 3 is significantly different, and in particular significantly darker if represented in grey tones, relative to the image of the lithium-ion batteries which are desired to be rejected from the waste stream 6 due to the risk of explosion inside the mill 3 (highlighted above), and also relative to the images of most other undesirable components typically found in material derived from a separate waste collection of used and / or retired batteries.

[0088] Based on this consideration, one or more threshold data 16 may be set first, the value of which is used to represent each point of the image, such as a threshold value of a gray tone value, and the threshold (or thresholds) are used to compare the value of each point or pixel of the current image 14 in the analysis step to evaluate whether lithium or other elements that are expected to be eliminated exist in the object A in the detection position 11 when the current image 14 is acquired. However, pixel-by-pixel point-by-point evaluation will inevitably lead to a high false positive rate.

[0089] To avoid this, the processor 15 may alternatively or additionally advantageously implement an image range or image region range analysis in order to identify a non-negligible number of pixels, and preferably to identify consecutive pixels in a region of non-negligible size having a value representing lithium or other elements that are desired to be rejected. In this way, only objects containing non-negligible amounts of lithium or other materials, respectively blocks of lithium or other undesirable materials of non-negligible size, are rejected.

[0090] As a further possibility, as an alternative or additional consideration to one or more of the foregoing, the processor 15 implements a comparative analysis between the current image 14 or a region thereof and a sample image 17. The sample image 17 includes images of lead-acid batteries, lithium-ion batteries, other types of batteries and batteries, and / or other objects that are not common in materials from separate waste collections of used and / or retired batteries, in their respective various geometries and standard sizes or in any case common sizes. The specific geometry of lead-acid batteries and other batteries and objects, as well as the geometry of their internal components, and their mutual relationships, can therefore be advantageously used as a sole criterion or a further criterion during the analysis of the current image 14.

[0091] Alternatively and / or additionally, the sample images 17 may represent one and the same type of object (or the object according to minor variations) in various orientations and / or various positions within the detection location 11, thereby eliminating the need to apply any rotation-translation and / or sliding window algorithms in the comparison between the images.

[0092] Alternatively or additionally, a process may be performed which provides for searching the current image 14 for an area corresponding to a single object A or a portion thereof and cancelling the information content of the remainder of the current image 14 or extracting a secondary image and then performing a comparison step with threshold data 16 and / or a sample image 17 on the cleaned image or secondary image.

[0093] As mentioned above, another problem is related to the fact that two or more different objects may be present simultaneously in the detection location 11, possibly partially or completely overlapping along said direction Z. Experimental tests have shown that even a small non-overlapping area between a lead-acid battery and a lithium-ion battery allows the detection of the lithium-ion battery. However, in case of a complete overlap between a larger lead-acid battery and another smaller object (regardless of which is uppermost and which is lowermost), it may be difficult (if not impossible) to detect the smaller object, at least for the operator P, especially when represented in gray tones. The embodiments disclosed above with a double exposure source and / or with a plurality of X-ray sources, in addition to advantageously being able to represent with false color images that are more pleasing to the operator, also allow such drawbacks to be overcome by reducing to a minimum false actuations and, more importantly, by reducing the number of cases in which lithium-ion batteries reach the mill 3 or the grinding step 106, and by limiting them to lithium-ion batteries of small size (which therefore cause small explosions inside the mill 3).

[0094] As mentioned, the processor 15 is preferably of the neural network type, has self-learning capabilities, and advantageously implements a classifier. The sample images 17 are preferably grouped into categories according to the desired affinity criteria. The learning of the processor 15 can be supervised by the operator P, for example by having the processor 15 present the current image 14, any sample images 17 and the suggestions for automatic decisions to the workstation 18 in a manner similar to that described above, and wait for the operator P to make a decision, from which to learn and refine its decision criteria.

[0095] In the case where the ejection device 41 is an anthropomorphic arm robot, the processor 15 can also personalize the position of the object to be removed within the detection position 11 and send it to the robot to facilitate its grasping.

[0096] In the embodiments discussed above, the relative movement between the objects A and the X-ray detector 10 is given by the fact that the objects A are conveyed on a conveyor, while the source 12 and the array 13 of detection elements (and possibly other components of the X-ray detector 10) are advantageously stationary. Alternatively, one or more slides may be provided for moving the source 12 and the array 13 (and possibly other components of the X-ray detector 10) through the detection position 11, and then a certain number of objects A are advantageously inserted into the detection position 11, kept stationary there long enough to scan the entire detection position 11, and subsequently replaced by other objects A. In addition to loading and unloading manually or by a robot arm, this can also be done by means of, for example, a "carousel" feeder, which comprises a disc plane divided into several sheet-like compartments and which rotates in such a way that one compartment is presented at a time in the detection position 11.

[0097] According to another alternative, the detection elements can be arranged in a two-dimensional array, providing a single slide for moving (one or more) X-ray sources, or according to yet another alternative, providing multiple X-ray sources or components for widening the X-ray beam, so that no relative movement between the X-ray detector 10 and the object A is required to capture a two-dimensional image of the detection position 11.

[0098] According to a further alternative, the above detection and analysis operations may be performed on a one-dimensional image corresponding to a single scan line, but such analysis may be more susceptible to errors since it may be based solely on the identification of constituent elements and may not be based on a comparison with the sample image 17 .

[0099] A presence and / or height detector of object A may advantageously be provided upstream of detection location 11 in order to improve the information content of the image, for example by varying the intensity of the emitted radiation and / or by normalizing the values ​​detected along the scan relative to a maximum height within the scan.

[0100] In order to reduce the problem of overlapping objects, upstream of sorting there may be a mechanical system causing the overlapping objects to fall down, for example a rod suspended at a given height above the conveyor belt 31 .

[0101] In the above, it is considered that the value of each pixel represents an indicator directly related to the radiation attenuation at the corresponding detection element. However, the analysis step of the process can be performed on other indicators related to radiation attenuation, such as the color associated with the value of each pixel, the average value, the minimum value, the maximum value, the value calculated by statistical or mathematical analysis of various pixel values, etc. According to this specification, various implementation possibilities are within the skill of those skilled in the art.

[0102] In general, any indicator that is related to the modification of X-rays by object A may be used.

[0103] It is worth emphasizing that in the prior art plants for processing used and / or retired lead-acid batteries, a sorting device is made by the fact that along the conveyor belt feeding the mill there are one or more magnets (e.g. electromagnets) which capture small metal, in particular ferrous pieces, such as screws, nuts, etc. Note that in the plant 1 according to the invention, the use of such magnets can be advantageously avoided. The plurality of objects A undergoing the process can therefore advantageously include the unsorted portion of a separate waste collection of used and / or retired batteries.

[0104] It should be understood that the material 7 to be ground can be temporarily stored in any device and / or container downstream of the sorting before being input into the mill 3 .

[0105] It should be understood that the components for storing the current image 14 and the components for storing the sample image 17 can be implemented in any manner and with any kind of physical or virtual support, locally and / or remotely. Likewise, the processor 15 can be hardware, firmware and / or software implemented locally and / or remotely in various manners, not necessarily by a single processor device. Various data and control signals can be exchanged directly or even indirectly between the various components of the plant through any wired or wireless connection and through any suitable communication protocol or combination of different protocols.

[0106] The above is a description of various embodiments of aspects of the invention, and further changes may be made without departing from the scope of the present invention. The shapes and / or sizes and / or positions and / or orientations and / or the order of various steps of various components may be changed. The functions of an element or module may be performed by two or more components or modules, and vice versa. Components shown as being directly connected or in contact with each other may have an intermediate structure arranged between them. Steps directly shown after each other may perform intermediate steps between them. The details shown in the figure and / or described with reference to the figure or embodiment may be applied to other figures or embodiments. Not all details shown in the figure or described in the same context must appear in the same embodiment. Features or aspects that prove to be innovative relative to the prior art, alone or in combination with other features, should be regarded as being described by themselves, regardless of what is explicitly described as innovative.

Claims

1. A waste and / or retired battery processing plant (1), comprising: Grinders (3), at least one separator stage (4) to separate the lead from other materials downstream of the grinder (3), and a sorting device (2) upstream of the grinder (3) configured to receive a plurality of objects (A) originating from a separate waste collection of used and / or retired batteries and to divert objects (A) other than lead-acid batteries from the processing workflow so that they do not enter the grinder (3), wherein the sorting device (2) comprises an X-ray detector (10) configured to perform an X-ray scan on the plurality of objects (A) and a processor (15) configured to analyze (103, 104, 205, 206, 212, 213) for each object (A) whether the X-ray scan indicates that the object is not a lead-acid battery, wherein the X-ray detector (10) comprises an X-ray source (12) configured to emit a radiation beam (48, 58) and at least one array of X-ray detection elements (13, 57) arranged at a predetermined position within a path of the radiation beam emitted by the X-ray source (12), wherein the X-ray source (12) is a dual emission source capable of emitting a second radiation beam at a different energy relative to the radiation beam (48, 58), or the X-ray detector (10) includes at least one second X-ray source (51), which is configured to emit a second radiation beam at a different energy relative to the radiation beam (48, 58), and wherein the X-ray detection element array (13) is a dual exposure detector or the X-ray detector (10) includes at least one second X-ray detection element array (53), the dual exposure detector or the at least one second X-ray detection element array (53) is arranged at a predetermined position within the path of the second radiation beam, and wherein the current image (14) representing the X-ray scan of at least a portion of the object (A) is a false color image.

2. The processing plant (1) according to claim 1, wherein the processor is configured to perform the analysis based on a comparison between a current image (14) of an X-ray scan representing at least a portion of the object (A) and threshold data (16) and / or a sample image (17).

3. The processing plant (1) according to claim 1 or 2, wherein the X-ray detection elements of each of the at least one X-ray detection element array (13, 57) are arranged on a curved surface at substantially the same distance from the X-ray source (12).

4. The processing plant (1) according to claim 1 or 2, wherein the X-ray detector (10) is configured to perform the X-ray scan of the plurality of objects (A) along two mutually orthogonal directions (X, Z).

5. The treatment plant (1) according to claim 1 or 2, wherein the processor (15) is provided with artificial intelligence.

6. A processing plant (1) according to claim 5, wherein the processor (15) is connected in a network (R) with an identical or compatible remote system (S) and is configured to receive additional and / or updated sample images and / or threshold data from the remote system (S).

7. The treatment plant (1) according to claim 6, wherein the processor (15) is configured to transmit its own sample image (17) and / or its own threshold data (16) to the remote system (S).

8. The treatment plant (1) according to claim 5, wherein the processor (15) is capable of learning and / or is of the neural network type.

9. A processing plant (1) according to claim 1 or 2, wherein the sorting device (2) includes a conveyor belt (31) for conveying the plurality of objects (A) at the X-ray detector (10) and an ejection device (42), wherein the ejection device (42) is arranged along the conveyor belt (31) downstream of the X-ray detector (10).

10. The processing plant (1) according to claim 9, wherein the conveyor belt (31) and the X-ray detector (10) are arranged inside a tunnel (34) connected to the mouth (33) of the grinder (3).

11. Treatment plant (1) according to claim 10, wherein the tunnel (34) is provided with a suction system and / or is free of magnets.

12. A process (100) for treating waste and / or retired batteries, comprising the following steps: a) feeding (101) a plurality of objects (A) originating from a separate waste collection of used and / or retired batteries to a processing plant (1), said objects (A) nominally comprising lead-acid batteries as well as different types of batteries and objects, b) grinding (106) an object of the plurality of objects (A), c) separating the lead from other materials after step b) (107), wherein the following steps are performed before step b): i) performing (102) an X-ray scan of the plurality of objects (A), and ii) for each object (A), analyzing (103, 104, 205, 206, 212, 213) whether the X-ray scan indicates that the object is not a lead-acid battery, and in the affirmative, deviating (105, 210) the processing operation sequence of said object (A); in the negative case, forwarding said object (A) to step b), In step ii), a false-color current image (14) representing an X-ray scan of at least a portion of the object (A) is analyzed.

13. The process according to claim 12, wherein in step ii), it is checked whether the object (A) contains at least one element selected from the group consisting of lithium, nickel and cadmium, said checking being performed by comparing at least one indicator related to the X-ray change of the object (A) with at least one corresponding threshold value.

14. The process of claim 13, wherein the at least one element is selected to be lithium.

15. The process according to claim 13, wherein in step ii), it is checked whether the object (A) contains a block made of at least one element selected from the group consisting of lithium, nickel and cadmium, said checking being performed by comparing at least one indicator related to the X-ray change of the object (A) with at least one corresponding threshold value.

16. The process of claim 15, wherein the at least one element is selected to be lithium.

17. A process according to claim 13 or 15, wherein the indicator is or is related to X-ray attenuation.

18. The process according to claim 12 or 13, wherein in step ii) a current image (14) of an X-ray scan representing at least a portion of the object (A) is compared with a sample image (17) of a lead-acid battery and / or an object other than a lead-acid battery.

19. Process according to claim 12 or 13, wherein said step ii) comprises an automatic analysis (205, 206) and / or an analysis (212, 213) performed by an operator (P).

20. Process according to claim 12 or 13, wherein the plurality of objects (A) fed in step a) forms an unsorted part of a separate waste collection of used and / or retired batteries.

Images