Method for cold extrusion of recovered metal alloy material and associated system

Abstract

Method for cold extrusion of recovered metal alloy material and associated system, characterized in that it comprises a phase of mechanical separation of contaminating materials, pressing and extrusion, and winding adapted to obtain, by extrusion, a continuous thread of metal alloy or a metal alloy ingot, starting from the processing of recycled materials such as lead pipes, nose cones or shooting pellets. In a variant of the invention, there are further phases of volumetric reduction of the material to be treated, preliminary cleaning, screening and round barreling, so as to reduce all the possible contaminating agents of the metal alloy and to reduce the material to be treated to a suitable size for the phases of mechanical separation of contaminating materials, pressing and extrusion, and winding.

Description

[0001] “Method for cold extrusion of recovered metal alloy material and associated system”

[0002] Description

[0003] Field of the invention

[0004] The invention refers to the field of mechanical and metallurgical processing, specifically to the processing by plastic deformation of recovered metal alloys.

[0005] Prior art

[0006] There are numerous fields in which metal alloys have been and are still used which can be recovered at the end of the life of the object, thus exploiting the intrinsic value of the material without waste and reducing the demand for the extraction of further raw materials, benefiting the conservation of environmental resources.

[0007] One case among all is that of firearm ammunition, usually made of lead alloy and tin alloy. Once the projectiles explode, they disperse into the environment. A high concentration thereof can be found in specific areas of ranges or shooting ranges, used for sports or military training. Another example is that of abandoned hydraulic pipes, no longer usable, such as tin and / or lead pipes from demolition works. Another field of recovery, although this is already widely exploited due to the high intrinsic value of the metal, is that concerning electrical connections in copper alloy wire.

[0008] To date, the recovery methods of said raw materials can generally all be summarized in a more or less reduced combination of the following phases:

[0009] • collection of the material to be reclaimed;

[0010] • preparation of the recovered material;

[0011] • chemical treatment of the recovered material;

[0012] • complete melting of the recovered material;

[0013] • control of the chemical composition and possible correction of the composition according to needs; • casting into ingots or into various types of shapes according to various needs;

[0014] • subsequent mechanical processing for plastic deformation or chip removal.

[0015] An example thereof is patent CN101636512A, which describes a method adapted to extract, by means of the use of various chemical processes, the percentage of pure lead from alloy articles containing said element in percentage. However, said patent has numerous critical issues, such as the use of substances like ammonium carbonate or sulfuric acid, which are difficult to dispose of and in any case have a very high ecological impact. If, on the one hand, this method allows obtaining lead with high levels of purity, its energy expenditure is very high, translating into equally high operating costs. In many applications, such as the previously mentioned case of firearm ammunitions, such stringent control on the percentage of lead or other elements is not necessary, and would result in a waste of resources.

[0016] A further example of the prior art in recycling metal alloys, and in particular lead, is represented by patent W02020151771A1, describing a metallurgical furnace suitable for the treatment and recycling of lead alloy material. In particular, the process involves a complete melting of the recycled material and a subsequent separation, according to the elements and characteristics of interest. Said process requires a large expenditure of energy, due to the complete melting and subsequent solidification of the material to be reclaimed. Furthermore, a further contamination of the composition during the ingot casting is inevitable, which effectively worsens the chemical composition of the material, requiring additions of raw materials with a higher level of purity. The melting and solidification process is also affected by numerous other problems related to environmental pollution and operator safety, as it generates volatile waste materials such as ash, dust and other melting waste, which are highly polluting and harmful to health.

[0017] The processes described so far are mandatory when an exact chemical composition of the alloy is necessary. For example, the case of electrical copper alloy wires can be mentioned, where a contamination would compromise the resistivity characteristics of the metal alloy used and consequently its operation. There are many other applications where such a stringent control of the composition of the alloy is not strictly necessary, but rather a random batch check of the treated recovered material is sufficient, starting from the principle that a reuse and not a complete recycling of said material is possible. For example, in the field of firearm ammunitions, lead and / or tin alloy pellets are widely used, which do not require very a stringent concentration precision of the elements. Said articles can actually be produced starting from recovered material of the same type, such as already exploded lead and / or tin alloy pellets, with low energy expenditure and almost zero environmental impact, through a method which involves mechanical processing by plastic deformation carried out cold, or in any case with a rise in temperature always below the melting temperature.

[0018] The patent application in question proposes a method for processing recovered metal alloys, focused on optimizing the process, carried out by means of cold extrusion, following preparation of the recovered material, so as to reduce all the contaminating elements.

[0019] Description of the invention

[0020] According to the present invention, a method is created for the cold extrusion of recovered metal alloy material and associated system which effectively solves the above problems.

[0021] Said method is specifically divided into three main phases:

[0022] • mechanical separation of the contaminating materials;

[0023] • pressing and extrusion;

[0024] • winding.

[0025] The material to be treated, for example resulting from the reclamation of ranges or shooting ranges, is subjected to the first phase of mechanical separation of contaminating materials, where a kinetic belt imparts a horizontal velocity component to said material to be treated, which is equal to the sliding velocity of the belt itself. Subsequently, at the end of said belt, the material to be treated continues its motion in free fall and is simultaneously hit by an air flow generated by a special flow generator. Said flow increases the horizontal velocity component in an inversely proportional manner to the weight of the individual debris, heavier if it is a metal alloy and lighter if it is plastic or organic polluting material, allowing positioning a container for collecting the material to be treated closer to said kinetic belt and a waste material collection container farther away from said kinetic belt.

[0026] The subsequent pressing and extrusion phase consists of loading the material to be recovered into a compression chamber, which is pressurized by a mechanical press. One or more extrusion nozzles allow the extrusion of the recovered material in the form of a continuous thread of the metal alloy present in the specific starting material to be treated.

[0027] In a variant of the present method, said compression chamber can be heated, in any case below the melting temperature of the treated metal alloy, so as to facilitate the subsequent pressing and extrusion phase, also reducing the accumulation of residual stresses.

[0028] After said pressing and extrusion phase, the winding phase is carried out, where the continuous metal alloy thread exiting from the extrusion nozzle is wound onto a cylindrical roller powered by the relative electric motor. In a variant of the method in question, prior to said winding phase, said metal alloy thread can be subjected to a cooling phase, carried out through a flow of air or water, allowing the residual stresses accumulated in the pressing and extrusion phase to be reduced and to carry out a heat treatment aimed at improving the mechanical characteristics of said metal alloy thread.

[0029] If said material to be recovered initially has a size which is not suitable for loading in said compression chamber, it can first be subjected to a volume reduction phase carried out through a single-shaft shredder, provided with an exit filtering grid, adapted to allow only the debris which has reached the desired size to exit from said machinery, represented by the dimensions of the holes in said filtering grid.

[0030] If said material to be treated comes from the reclamation of ranges or shooting ranges, and is therefore fundamentally composed of lead and / or tin alloy nose cones or pellets, or in any case in all cases in which material with already reduced sizes is treated, the main objective is to reduce the presence of contaminating debris as much as possible which, once embedded inside the continuous metal thread or ingot, would reduce the purity levels of said metal alloy. To this end, the following phases can be carried out before said phase of mechanical separation of contaminating materials:

[0031] • preliminary cleaning; • screening;

[0032] • round barreling.

[0033] In the preliminary cleaning phase, said material to be treated is inserted into a mechanical screw comprising a transport tube, adapted to obtain an effective separation of all the debris, so as to facilitate the subsequent phases.

[0034] The screening phase involves loading said material to be treated into a circular sieve, adapted to carry out an initial separation of the debris, according to the different densities of the contaminating materials with respect to the metal alloy to be recovered.

[0035] The round barreling phase involves the use of a rotobarrel rotating on rollers, into which the material to be treated is loaded. The platform on which are fixed the rollers adapted to allow the circular motion of the rotobarrel comprises hinges adapted to allow the partial tipping of the rotobarrel, so as to facilitate the unloading operations of the material once treated. Said roto barrel comprises a radially extending structure therein, which can be of various geometry and shape, however fixed on the shell of said rotobarrel, adapted to carry out the separation of the metal alloy material to be recovered from the contaminating materials, thanks to the repeated impacts between said radial structure and the material to be treated. Subsequently, said rotobarrel is crossed by an air flow, possibly hot and dry, generated by a blower-aspirator. An appropriate discharge pipe conveys the air loaded with suspended debris towards a debris collection tank, separating said material to be recovered from said contaminating material.

[0036] In a version of the invention in question, at least one of the passages from one processing phase to another is carried out according to an automated transport system, without requiring the intervention of a human operator.

[0037] The advantages offered by the present invention are evident in the light of the description presented thus far and will be even clearer thanks to the attached figures and the related detailed description.

[0038] Description of the figures

[0039] The invention will be described hereinafter in at least a preferred embodiment by way of non- limiting example with the aid of the appended figures, in which:

[0040] - FIGURE 1 shows a sectional view of the kinetic belt 101 adapted to carry out the phase of mechanical separation of contaminating materials 100, the mechanical press adapted to carry out the pressing and extrusion phase 200, the cylindrical roller 301 adapted to carry out said winding phase 300 , the heating collar 401 adapted to carry out said pre-heating phase 400 and the cooling system 501 adapted to carry out said cooling phase 500.

[0041] - FIGURE 2 illustrates the single-shaft shredder 602 adapted to carry out said volumetric reduction phase of the recovered metal alloy material 600.

[0042] - FIGURE 3 shows the mechanical screw 702 adapted to carry out the preliminary cleaning phase 700 and the circular sieve 801 adapted to carry out the screening phase 800.

[0043] - FIGURE 4 shows a side sectional view of the rotobarrel 901 adapted to carry out the round barreling phase 900.

[0044] - FIGURE 5 shows a front sectional view of the rotobarrel 901, highlighting the radial extension structure 910 fixed on the internal shell of said rotobarrel 901.

[0045] Detailed description of the invention

[0046] The present invention will now be illustrated by way of a purely non-limiting or binding example, resorting to the figures which illustrate some embodiments with respect to the present inventive concept.

[0047] FIG. 1 shows the kinetic belt 101, adapted to impart, through its movement, a horizontal velocity component to the material to be treated which is placed on top of it. The material to be treated then continues in free fall, encountering an air flow which is also horizontal, generated by an air flow generator 102, which increases the horizontal velocity of each debris, in a manner inversely proportional to the specific weight of the debris itself, allowing the collection of the metal alloy material to be recovered and therefore heavier, in a collection tank of the material to be recovered 103 placed near said kinetic belt 101 and a collection tank of the contaminating material 104, placed farther away from said kinetic belt 101.

[0048] Said kinetic belt 101 is adapted to carry out the phase of mechanical separation of contaminating materials 100, allowing to obtain, starting from a mixed material to be treated, an accurate division of metal alloy material to be recovered and contaminating material. FIG. 1 also illustrates a mechanical press 202, comprising a loading hopper 203, a compression chamber 204, at least an extrusion nozzle 205 and a motor powering the mechanical press 201. Said mechanical press 202 is adapted to carry out the pressing and extrusion phase 200, which allows obtaining, through the pressure imposed, in output from said compression chamber 204, a metal alloy thread, which can be used for subsequent applications and processes.

[0049] In a variant of the invention said compression chamber 204 is surrounded by a heating collar 401, adapted to raise the temperature of the material to be recovered inserted inside said compression chamber 204 in the heating phase 400, thus improving the subsequent phase of pressing and extrusion 200, obtaining a metal alloy thread with a homogeneous composition and with a lower presence of residual stress accumulations.

[0050] FIG. 1 lastly shows said cylindrical roller 301 and said electric winding motor 302, adapted to carry out the winding phase 300 of the metal thread exiting from said extrusion nozzle 205.

[0051] In a variant of the invention said winding phase 300 is preceded by a cooling phase 500, carried out by means of a cooling system 501, adapted to lower the temperature of the metal thread exiting said extrusion nozzle 205.

[0052] FIG. 2 shows a single-shaft shredder 602 with relative loading hopper of the single-shaft shredder 601, filtering grid 603 and discharge opening 604. In the volumetric reduction phase of the recovered metal alloy material 600, said recovered material, whose size is not yet small enough to be loaded into said compression chamber 204, is inserted in said single-shaft shredder 602. The debris then manages to pass through said discharge opening 604 only after passing said filtering grid 603, characterized by a multiplicity of holes of dimensions equal to the desired size of said metal alloy debris.

[0053] If the material to be treated comes from the reclamation of ranges, shooting ranges, or similar, preliminary treatment phases are necessary which are adapted to remove all the contaminating debris of various kinds, such as plastic, organic or other debris. Specifically, the following phases are suitable for this purpose: preliminary cleaning 700; screening 800; round barreling 900.

[0054] In said preliminary cleaning phase 700, said material to be treated is inserted in a mechanical screw 702, through a loading hopper of the mechanical screw 701 and then exits through a discharge tube 703. Said preliminary cleaning phase allows the separation of the material debris to be recovered from the contaminating material debris.

[0055] Subsequently, the screening phase 800 is carried out, through a circular sieve 801, comprising a discharge pipe 802 and a loading opening 803. Said screening phase is adapted to carry out a further separation of the recovered material from contaminating agents, exploiting the different densities of the metal alloys and various types of residues.

[0056] Subsequently, the round barreling phase 900 is carried out, through a rotobarrel 901, comprising a material loading opening 902, a material unloading opening 903, at least a roller 904, an aspirator-blower 905, a suction pipe 906, a blowing tube 907 and a contaminated material collection tank 908. Said rotobarrel is rotated along its longitudinal axis on rollers which support it while simultaneously allowing the rotation thereof. Said rollers are fixed to a tipping platform (911) comprising at least a hinge adapted to allow the partial tipping of said rotobarrel 901 so as to facilitate the unloading operations of the treated material. Said rotobarrel further comprises, fixed on its internal shell, at least a radially extending structure 910, adapted to make impacts with said material to be treated during rotation. Said repeated impacts naturally cause the separation between the material to be recovered and the contaminating elements. In said round barreling phase 900, said aspirator-blower 905 is adapted to generate a flow of air inside said barrel 901, adapted to capture and transport the contaminating debris, lighter and with a reduced volume with respect to the material to be recovered, inside said contaminating material collection tank 908.

[0057] In a version of the invention, the transport of the material to be recovered, between all or at least two of the previously described phases, is carried out through an automated handling system, which does not require the intervention of a human operator. Finally, the use of said method for cold extrusion of recovered metal alloy material and associated system is envisaged so as to make ingots of recovered metal alloy material suitable for subsequent mechanical processing by plastic deformation or chip removal. Said use is obtained by blocking the output flow from the compression chamber 204 through said extrusion nozzles 205, obtaining a pure compression of the material to be recovered, which will take the shape of an ingot equal to the shape of said compression chamber 204. All the phases prior to said pressing and extrusion phase 200 remain applicable and unchanged.

[0058] Finally, it is clear that modifications, additions or variations that are obvious to a person skilled in the art can be made to the invention described so far, without thereby departing from the scope of protection provided by the attached claims.

Claims

Claims1. Method for cold extrusion of recovered metal alloy material, characterized in that it comprises the following phases:• mechanical separation of contaminating materials (100) from the recovered metal alloy material, carried out through a kinetic belt (101) capable of imparting a horizontal velocity component to the material to be treated, said horizontal velocity further increased during the fall of said material to be treated by a horizontal air flow, generated by an air flow generator (102), in a manner inversely proportional to the weight of the particles of said material to be treated, thus conveying the material to be recovered into a collection tank (103), closest to said kinetic belt (101) the heaviest material to be recovered, and in a polluting material collection tank (104), furthest from said kinetic belt (101) the lightest debris of polluted material;• pressing and extrusion (200), in which said material to be recovered, obtained from said mechanical separation phase of contaminating materials (100), is conducted through a loading hopper (203) into a compression chamber (204) comprising at least an extrusion nozzle (205), subsequently said material to be recovered is put under pressure by a mechanical press operated by the relative power motor (201) of the mechanical press (202) at a pressure level sufficient to obtain, by plastic deformation, output from said extrusion nozzle (205) a continuous thread made of said material to be recovered;• winding (300), in which said continuous thread exiting from said extrusion nozzle (205) is wound into a rotating cylindrical roller (301) powered by the relevant electric winding motor; obtaining a continuous thread of metal alloy starting from the initial recovered material, suitable for subsequent mechanical processing and transformations.

2. Method, according to the previous claim 1, characterized in that said pressing and extrusion phase (200) is preceded by a preheating phase (400) of the recovered material, in which said material is heated to a temperature, however, always lower than the melting temperature of the treated metal alloy, suitable for facilitating its extrusion and reducing the accumulation of residual stresses.

3. Method, according to the previous claim 2, characterized in that after said preheating step (400) and pressing and extrusion phase (200) and prior to said winding phase (300) a cooling phase (500) is carried out, through a water or air cooling system (501), capableof reducing the temperature of the yam and / or carrying out a heat treatment of the continuous metal alloy yarn thus obtained, improving its mechanical characteristics.

4. Method, according to any of the previous claims, characterized in that prior to said phase of mechanical separation of contaminating materials (100), a phase of volumetric reduction of recovered material is carried out in metal alloy (600), through a single-shaft shredder (602), including at least a loading hopper of said single-shaft shredder (601), a filtering grid with holes of a suitable diameter to allow the passage of only the debris that has reached the size suitable for loading into said compression chamber (204) and an exhaust opening (604).

5. Method, according to the previous claims 1, 2, 3, characterized in that prior to said phase of mechanical separation of contaminating materials (100), in the case in which the recovered material whether they are lead nose cones or pellets resulting from the reclamation of grounds of shooting ranges or shooting ranges or in any case small-sized material to be treated, a preliminary cleaning phase (700) is carried out through a mechanical screw (702), including at least a hopper loading capacity of the mechanical screw (701) and a transport tube (703), designed to move the material coming from the reclamation of shooting ranges or ranges, carrying out an initial separation between pellets, bullets and soil residues and other contaminating elements.

6. Method, according to any of the previous claims, characterized in that following said preliminary cleaning phase (700) a screening phase (800) is carried out through a circular sieve (801), comprising at least a discharge pipe (802) and a loading opening (803), suitable for carrying out a further separation of the recovered material from contaminating agents, exploiting the different densities of the metal alloys and residues of various kinds.

7. Method, according to any of the previous claims, characterized in that prior to said mechanical separation phase of contaminating materials (100), a round barreling phase(900) is carried out through a rotobarrel (901) comprising, fixed on its internal shell, at least a radially developed structure (910) suitable for separating said material to be recovered from said contaminating material thanks to the repeated impacts made between said radially developed structure (910) and the material to be process, said rotobarrel(901) moved by at least a roller (904) fixed to a tipping platform (911) and comprising at least a material loading opening (902) and a material unloading opening (903), said rotobarrel (901) being connected through at least a suction pipe (906) and a blowing pipe (907) to a blower-aspirator (905), comprising at least a collection tank for contaminatingmaterial (908), capable of generating a flow of air, possibly hot and dry, suitable for separating said contaminating material from said pellets or nose cones or in any case small-sized metal alloy products.

8. Method, according to any of the previous claims, characterized in that at least a passage of said material to be treated between two previously described contiguous phases is carried out through an automated handling transport system, not requiring the intervention of a human operator.

9. System for cold extrusion of recovered metal alloy material, characterized in that it includes the following assemblies:• a kinetic belt (101), an air flow generator (102), a collection tank for the material to be recovered (103) and a polluting material collection tank (104), suitable for carrying out said mechanical separation phase of contaminating materials (100) described in claim 1;• a mechanical press (202) comprising a feeding motor (201), a compression chamber (204) with relative loading hopper (203) of the compression chamber (204) and at least an extrusion nozzle (205), suitable for carrying out said phase of pressing and extrusion (200) previously described in claim 1;• a cylindrical roller (301) powered by an electric winding motor (302) capable of carrying out said winding phase (300) previously described in claim 1.

10. System, according to the previous claim 9, characterized in that it comprises a further assembly comprising a heating collar (401) suitable for heating said compression chamber (204) through an electrical resistance suitably powered, suitable for carrying out said preheating phase (400) previously described in claim 2.

11. System, according to the previous claim 9 or 10, characterized in that it comprises a cooling system (501) powered by water or by a forced flow of air, suitable for carrying out said cooling phase (500) previously described in claim 3.

12. System, according to the previous claim 9 or 10 or 11, characterized in that it comprises a single-shaft shredder (602) comprising a loading hopper of the single-shaft shredder (601), a filtering grid (603) and a discharge opening (604), suitable for carrying out said phase of volumetric reduction of the recovered metal alloy material (600) previously described in claim 4.

13. System, according to any of the previous claims 9-12, characterized in that it comprises a mechanical screw (702) including a loading hopper of the mechanical screw (701) anda transport tube (703), suitable for carrying out said preliminary cleaning phase previously described in claim 5.

14. System, according to any of the previous claims 9-13, characterized in that it comprises a circular sieve (801) comprising a discharge pipe (802) and a loading opening (803), suitable for carrying out said screening step (800), previously described in said claim 6.

15. System, according to any of the previous claims 9-14, characterized in that it comprises a barrel (901), comprising at least a radially developed structure (910) fixed on the internal shell of said barrel (901), a material loading opening (902), a material unloading opening (903), a roller (904) fixed to a tipping platform (911), an aspirator-blower (905) suitable for introduce air possibly pre-treated to be hot and dry into the barrel, a suction pipe (906), a blowing tube (907) and a debris collection tank (908), suitable for carrying out said barrel barreling phase (900) previously described in said claim 7.

16. Use of said system characterized in that it operates said compression chamber (204) while keeping said extrusion nozzle (205) plugged, suitable for obtaining a compact ingot of recovered alloy material metallic, suitable for subsequent mechanical processing.

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