Method and plant of regenerating and upgrading graphite powder from industrial production waste

Abstract

A method of regenerating and upgrading graphite from industrial production waste, comprising the provision of graphite powder of predetermined grain size obtained from said waste and treatment thereof with oily additives to reduce its dustiness and obtain a multifunctional semi-finished product, said semi-finished product being subsequently mixed with resins of various types to make items and / or surface coverings of articles of rigid, semi-rigid or flexible materials, suitable to confer them innovative mechanical, chemical and optical properties. There is also provided a plant (1) for the implementation of this regeneration and upgrading method.

Description

METHOD AND PLANT OF REGENERATING AND UPGRADING GRAPHITE POWDER FROM INDUSTRIAL PRODUCTION WASTEDESCRIPTIONField of application

[0001] The present invention is generally applicable to the sector of technologies for the management of industrial production waste and particularly relates to a method and a plant for regenerating and upgrading graphite powder obtained from unavoidable waste in the graphite electrode industry.Background art

[0002] It is known that thanks to the chemical-physical properties of graphite this material is nowadays used in various industrial sectors. Some of its main applications are the production of writing tools such as pencils, the production of refractory or insulating material, sealants, lubricants, dyes and paints, moulds, brushes for rotating electric machines and electrodes.

[0003] In recent years, the use of graphite for the production of EDM electrodes has intensified.

[0004] Generally, the production of graphite electrodes starts by collecting and storing the carbon-based raw materials. The raw materials are then crushed so as to obtain a more or less raw powder which is treated to remove impurities and residues.

[0005] The powder is then mixed with one or more binding agents in order to obtain a homogeneous product. The next phase consists in exerting an isostatic pressure on the powder to form homogeneous, isotropic graphite blocks, even large ones.

[0006] The blocks are then fired and graphitized to transform the carbon into crystalline graphite.

[0007] In the final phase, the graphite blocks are mechanically machined, generally using machine tools, in order to remove the excess material and make the electrodes.

[0008] Inevitably, due to the mechanical machining, a significant quantity of graphite is eroded from the block becoming a tailing material.

[0009] Generally, this tailing material is suitably sucked and removed from the processing area to be then disposed of as special waste.

[0010] Being considered a special industrial waste, the disposal of graphite powder is difficult and economically disadvantageous.

[0011] For this reason, the need is felt to recover at least part of the graphite waste by requalifying it for new uses. The result of this recovery is to reduce the quantity of material destined for disposal, and its transformation from fill material into semi-finished products and by-products pursuant to Art. 184 Legislative Decree 3.04.2006, no. 152.Technical problem

[0012] In light of the state of the art, the problem that the present invention aims to solve is to regenerate and upgrade the graphite powder from industrial production waste, in order to create a semi-finished product that can be easily handled and is less invasive, usable in different industrial sectors.Presentation of the invention

[0013] The object of the present invention is to solve the aforementioned problem by providing a method of regenerating and upgrading graphite powder from industrial production waste that has characteristics of high efficiency and great economy.

[0014] Another object of the present invention is to provide a regeneration and upgrading method of the type indicated above that recovers the graphite destined for disposal as much as possible.

[0015] A further object of the present invention is to provide a regeneration and upgrading method of the type indicated above that allows the creation of a final subproduct based on recovered graphite that can be used in different industrial sectors.

[0016] Another object of the present invention is to provide a regeneration and upgrading method of the type indicated above that has a reduced environmental impact.

[0017] A particular object of the present invention is to provide a plant for regenerating and upgrading graphite powder from industrial production waste that allows the implementation of the present method.

[0018] A further object of the present invention is to provide a plant of the type indicated above that is partially or totally automated and that does not require skilled labour during processing.

[0019] Another object of the present invention is to provide a plant of the type indicated above that reduces the waste of materials used in regeneration and upgrading.

[0020] The aforementioned purposes, as well as others that will appear more clearly below, are achieved by a method of regenerating and upgrading graphite powder from industrial production waste, in accordance with claim 1 .

[0021] The method comprises the provision of graphite powder of predetermined grain size and treatment thereof with oily additives to reduce its dustiness and obtain a multifunctional semi-finished product mixable with resins of various types to make items and / or surface coverings of articles of rigid, semi-rigid or flexible materials suitable to confer them innovative mechanical, chemical and optical properties.

[0022] In synergy with appropriate resins, the base material of the items and / or coverings obtained with the multifunctional semi-finished product exhibits high electrical, thermal and acoustic conductivity and constitutes an effective barrier to UV rays thanks to its lamellar composition. It is also an effective lubricant and anti-abrasive, it functions as an insulator at certain temperatures, as a thermal flywheel, and has electrostatic properties. When applied to metals, it functions as a passivator.

[0023] Thanks to its high resistance to the oxidation process, it can be used as a pigment allowing to obtain shades from black to medium grey to light grey, which would not be otherwise reproducible on wood, metal, fabric, plastic, rubber and textile fibres not otherwise obtainable.

[0024] Thanks to its lamellar structure, it can reflect sunlight and can be applied in the form of a varnish of various types both for the exterior and for the interior on wood, metals, plastic, rubber and textile fibres.

[0025] The addition of the oily additive increases the characteristics of virgin graphite, making it even more oily, especially in its use as a dye to replace the use of textile softeners, making the surfaces on which it is applied “silky”.

[0026] In one embodiment, the method comprises the steps of collecting at industrial processing sites graphite powder normally intended for decommissioning or disposal by means of large bags (big-bags), coarse filtering undifferentiated graphite powder to remove excess grain sizes and non-graphite waste subproducts from the powder, precision sieving to differentiate the graphite powder into different granulometries of predetermined value and treating the differentiated graphite powder in a controlled environment so as to obtain a multifunctional semi-finished product consisting of a regenerated and upgraded graphite powder with minimal air diffusion.

[0027] According to the invention, the step of treating the differentiated graphite powder comprises a sub-step of uniform distributing in hermetic conditions particles of an oily additive in predetermined percentages on the powders so as to obtain an intimate mixture of regenerated and upgraded graphite powders of differentiated grain sizes with oily additive.

[0028] In one embodiment, the granulometries in the range between 500pm and 20pm are obtained from the precision sieving. Preferably in the range between 400pm and 30pm.

[0029] In one embodiment, the oily additive is added in weighted percentage preferably in the range between 0.01% and 15% by weight with respect to the total weight of the graphite powder and more preferably in the range between 0.01 % and 1.5% by weight with respect to the total weight of the graphite powder.

[0030] The graphite powder obtained with the method reported above is regenerated and upgraded in the sense that it has a lower dustiness and can therefore be more easily handled for all the uses for which it is intended.

[0031] In addition, the regenerated and upgraded graphite powder has better chemical-physical properties than the starting graphite.

[0032] The invention also relates to a plant for regenerating and upgrading graphite powder from unavoidable scrap of industrial production, in accordance with claim 9.

[0033] The plant comprises a station for collecting graphite powder fromindustrial sites, a hopper for collecting filtered graphite powder, a vibrating sieve connected to the hopper to obtain powders of different granulometries and an apparatus for treating the powders of different granulometries comprising a mixer with a mixing chamber and an electronic control unit.

[0034] The mixing chamber is associated with a nebulization device having a plurality of nozzles for distributing an oily additive in a predetermined weight percentage on the graphite powders of different granulometries.

[0035] In one embodiment, the vibrating sieve has a hermetically sealed sieving chamber configured to separate graphite powder having particles of differentiated grain sizes.

[0036] In one embodiment, the treatment apparatus has weighing means for detecting a weighted quantity of differentiated graphite powder to be treated, introduction means of said detected weighted quantity into the mixing chamber, and dosing means for dosing a weighted percentage of oily additive to be added to the weighted quantity of graphite powders to be treated in the mixing chamber.

[0037] Thanks to this configuration, the plant can carry out a precise dosage of oily additive based on the quantity of incoming graphite powder, also intimately mixing large amounts of additive and graphite powder.

[0038] Advantageous embodiments of the invention are obtained in accordance with the dependent claims.Brief description of the drawings

[0039] Further characteristics and advantages of the invention will be more evident in the light of the detailed description of a method and a plant for regenerating and upgrading graphite powder from industrial production waste, illustrated by way of non-limiting example with the aid of the following drawing tables in whichFIG. 1 is a block diagram of the steps of the method of regenerating and upgrading graphite powders according to the invention;FIG. 2 is a sectional view of a detail of the vibrating sieve used in the plant of regenerating and upgrading graphite powders according to the invention;FIG. 3 is a front view of the apparatus used in the plant of regenerating and upgrading graphite powders according to the invention;FIG. 4 is a side view of the apparatus of Fig. 3.Detailed description of an example of a preferred embodiment

[0040] With particular reference to the figures, a method of regenerating and upgrading graphite powder from industrial production waste is illustrated, comprising the provision of graphite powder of predetermined grain size obtained from the waste and treatment thereof with oily additives to reduce its dustiness and obtain a multifunctional semi-finished product.

[0041] In the following, the term “regeneration and upgrading” will be understood as an action aimed at recovering and improving the chemicalphysical properties of graphite powders from industrial processing waste, and in particular the lower diffusion of powders in free air.

[0042] As visible in FIG. 1 , the method comprises an initial step of a) collecting at industrial processing sites graphite powder obtained from waste and normally destined for disposal in landfill.

[0043] By way of non-limiting example, a suitable collection site is given by industries that process graphite in order to obtain electrodes.

[0044] In these industries, the mechanical machining of graphite blocks is carried out, removing large quantities of graphite of different dimensions from the block that are promptly removed from the processing site.

[0045] These wastes can be sucked away so as to remove them and convey them away from the processing site to a special collection station.

[0046] Then, a step of b) coarse filtering the undifferentiated graphite powder is carried out to remove therefrom excess grain size and any non-graphite waste subproducts.

[0047] In one embodiment, during suction the powder can be passed through special filter nets adapted to block unwanted by-products so as to convey only graphite powder to suitable containers.

[0048] In one embodiment, these containers can be large bags (big bags) typically used in industrial environments, suitable to allow the handling of graphite powders avoiding dispersion in the surrounding environment. Thebags thus filled are transported to a special area where the subsequent phases of the method take place.

[0049] In particular, the bags are brought to an area provided with screens / sieves where a step of c) precision sieving is carried out to differentiate the graphite powder into granulometries of predetermined value.

[0050] Suitably, the graphite powder can be passed through a sectioned sieve having several sieves, or through a series of sieves each provided with a special sieve to block particles of a given size.

[0051] In doing so, it is possible to recover differentiated graphite powders, divided based on their grain sizes.

[0052] Advantageously, the precision sieving can be carried out by means of a vibrating sieve with combined jolting and rotary motion. In practice, the graphite powder is inserted into the vibrating sieve and by falling passes through it until it meets one or more sieves each formed by a filter net.

[0053] The dust accumulates on a net and the particles with dimensions smaller than the holes of the net pass through it passing to the next net until they exit the vibrating sieve where they are collected. The larger particles, on the other hand, remain on a mesh net with corresponding dimensions where they are either moved towards a second outlet or they are collected by the net itself at the end of the treatment when the vibrating sieve is stationary.

[0054] Thanks to the jolting and rotary motion of the vibrating sieve caused by one or more associated motors, the powder is homogeneously distributed throughout the net and the passage of fine powder through the net itself is facilitated, thus reducing any waste caused by a possible accumulation in occluded meshes of the net.

[0055] Preferably, the granulometries of predetermined value that are collected and destined for the subsequent steps of the method are those in the range between 500pm and 20pm.

[0056] More preferably, granulometries of value in the range between 400pm and 30pm are collected.

[0057] The different collectors each containing a certain grain size of powder are thus destined for the subsequent steps of the method.

[0058] There is provided a step of d) treating the graphite powder of different granulometries in a controlled environment to obtain a regenerated and upgraded graphite powder with minimal air diffusion.

[0059] In order to reduce the air diffusion, regenerate and upgrade the graphite powder, during the treatment step d), a sub-step of e) uniform distributing in hermetic conditions particles of an oily additive in predetermined percentages over the differentiated graphite powders is provided to obtain an intimate mixture of regenerated and upgraded graphite powders of different granulometries and oily additive.

[0060] In other words, a predetermined percentage quantity of the oily additive is added to the graphite powder based on the selected grain size.

[0061] Such a mixture of differentiated graphite powder and oily additive constitutes the multifunctional semi-finished product.

[0062] Suitably, the predetermined percentages of distribution of the oily additive are preferably relatively low, i.e. in the range between 0.01 % and 15% by weight with respect to the total weight of the graphite powder. More preferably, the predetermined percentages of distribution of the mineral oil are in the range between 0.01 % and 1 .5%.

[0063] This oily additive, selected from the group of mineral oils comprising, for example, the oil known as PHARMA H25, has the purpose of adhering to the graphite particles and retaining them so as to weigh them down and prevent their dispersion in the surrounding environment.

[0064] Furthermore, as described in more detail below, the suitably dosed oily additive also has the function of upgrading the powders by improving (upgrading) their chemical-physical characteristics.

[0065] To homogeneously and intimately mix such a low percentage of oily additive with the graphite powder, the step e) of distributing mineral oil particles is carried out by spraying with oily vapour.

[0066] According to a further peculiar aspect of the invention, in order to automate the regeneration and upgrading method described so far, and mass produce regenerated and upgraded graphite powder, a plant 1 for regenerating and upgrading graphite powder is provided.

[0067] Suitably, the plant 1 comprises a station for collecting graphite powder from industrial sites, not illustrated in the figures.

[0068] Therefore, the filtered graphite powder collectors obtained during phases a) and b) of the method described above are stored in this collection station.

[0069] A hopper is then provided for collecting the graphite powder, which is connected to a vibrating sieve 2 to obtain powders of different granulometries.

[0070] In one embodiment, not illustrated in the figures, the hopper may comprise a pipe provided with suction means adapted to be connected to a graphite powder collector to be treated. In doing so, the graphite powder will be directly taken from the collector, directed towards the hopper and then conveyed to the vibrating sieve 2, avoiding dispersion of graphite powder in the working environment.

[0071] Further, to further reduce the dispersion of graphite powder, the vibrating sieve 2 may be housed within a hermetically sealed casing.

[0072] As visible in FIG. 2, the vibrating sieve 2 has a hermetically sealed sieving chamber 3 configured to separate graphite powders having particles of different grain sizes.

[0073] Inside the sieving chamber 3 there is a series of stainless-steel filter nets with respective net tensioning rings.

[0074] In a preferred embodiment, the nets have a three-dimensional development, of substantially convex conical shape with convexity facing upwards, so as to facilitate the conveying and sieving of the graphite powder by gravity.

[0075] As described above, since the vibrating sieve 2 is of the combined jolting and rotary motion type, the filter nets are operatively connected in a manner known per se to an electric motor 4 which confers them such combined motion.

[0076] The requalification plant 1 also comprises an apparatus 5 for treating differentiated grain size powders, illustrated in FIGS. 3 and 4.

[0077] The treatment apparatus 5 has a mixer with mixing chamber 6, a control unit 7 and a nebulization device 8.

[0078] The mixing chamber 6 is formed by a box-like casing 9 having introduction means 10 of the graphite powder and at least one discharge duct11 for the exit of the final product, i.e. the multifunctional semi-finished product.

[0079] In one embodiment, the mixing chamber 6 has therein stirring means12 of the graphite powder for mixing it together with the added oily additive so as to obtain an intimate contact between the fine powder particles and the droplets of nebulised oily additive.

[0080] Preferably, the stirring means 12 are of the type with paddle, perforated basket, slats, auger and the like known in the art.

[0081] The nebulization device 8 associated with the mixing chamber 6 comprises a plurality of nozzles 13 for distributing an oily additive in a predetermined weight percentage on the graphite powders to be treated adapted to nebulize the oil.

[0082] Suitably, the oily additive is stored in a tank 14 connected to the plurality of spray nozzles 13 by means of a high-pressure pump 15. Furthermore, in order to suitably dose the oily additive, there are dosing means 16 associated with the nebulization device 8.

[0083] Preferably, the dosing means 16 comprise a litre counter suitable for receiving the predetermined quantity of oily additive before sending it to the plurality of nozzles.

[0084] An interface connected to the dosing means 16 and accessible by an external operator is provided to select the quantity of oily additive to be sprayed.

[0085] Finally, the electronic control unit 7 comprises electronic means for powering and implementing the various components of the requalification apparatus 5 when it is in operation and performs the various steps of the method of the present invention.

[0086] To further limit the dispersion of graphite in the surrounding environment, a fan 17 provided with a cartridge filter cleaning system 18 can be provided.

[0087] The operation of the plant 1 during the implementation of the method of regenerating and upgrading graphite powder is described below.

[0088] A collector from an industrial processing site (steps a) and b)) is connected to the vibrating sieve 2 and its contents are introduced inside so as to be sifted and divided based on the dimensions of the holes in the filter nets, carrying out the step c) of the method in question.

[0089] Each grain size collected is therefore discharged to the outside by means of special pipes 19 that lead to a respective collector B.

[0090] The differentiated graphite powder is then weighed by weighing means, not illustrated in the figures, adapted to detect the weighted quantity of differentiated graphite powder to be treated.

[0091] Once the weighted quantity of graphite present in a collector B has been detected, the latter is connected to the mixing chamber 6 by means of the introduction means 10.

[0092] The introduction means 10 comprise a loading hatch provided with a dust-proof rubber opening, through which the differentiated graphite powder is introduced into the mixing chamber 6.

[0093] Once the quantity of differentiated graphite powder introduced into the mixing chamber s is known, a predetermined weight percentage of oily additive to be added is selected. The selected weighted percentage of oily additive to be added to the graphite powder is dosed through the dosing means 16.

[0094] The operations of selecting the quantity of oily additive are carried out through the dosing means 16 using the interface accessible by an external operator.

[0095] The oily additive is sprayed in the selected quantity through the distribution nozzles 13 into the mixing chamber 6 where the graphite powder of given grain size is present.

[0096] Based on the final product to be made, the quantity of oily additive is selected between 0.01 % and 15% by weight with respect to the total weight of the graphite powder.

[0097] When the nebulization device 8 receives the signal from the dosing means 16, a solenoid valve is opened that controls the high-pressure membrane pump 15 in order to withdraw the established quantity of oily additive from the tank 14 and spray it on the graphite powder through thenozzles 13.

[0098] After adding the preset quantity of oily additive to the powder, the solenoid valve is closed and a gearmotor 20 is operated which starts mixing the powder and the oily additive inside the mixing chamber 6.

[0099] The stirring means 12 present inside the mixing chamber 6 act on the graphite powders sprayed by the oily additive so as to obtain an intimate contact between the fine particles of the powders and the droplets of nebulized additive.

[0100] Then, the steps d) of treatment and e) of uniform distributing the oily additive on the differentiated graphite powder are carried out inside the mixing chamber 6.

[0101] The gearmotor 20 then starts the stirring means 12 for a predetermined time until the final product is obtained. During the same period of time the fan 17 is activated, as well.

[0102] At the end of the treatment time, the gearmotor 20 is stopped and a drain valve is opened to let out the final product.

[0103] The treated and mixed graphite powders are transferred to the outside by means of the discharge duct 11 , controlled by the valve, which communicates with an external collection container R for the regenerated and upgraded graphite powders.

[0104] The collection container R of the final product, i.e. the multifunctional semi-finished product, is removable upon filling thereof and can be replaced with an empty container for a new treatment cycle.

[0105] Therefore, the final product of the method described above is a multifunctional semi-finished product composed of a mixture of graphite of a given grain size to which a quantity of oily additive has been added in predetermined weighted percentage.

[0106] Based on the grain size and the quantity of oily additive added, the final product has determined chemical-physical properties, which are superior to those of pure graphite.

[0107] The final product exhibits better thermal, thermal and acoustic conductivity, effectively blocks UV rays and has electrostatic and lubricatingproperties.

[0108] Therefore, the multifunctional semi-finished product obtained from regenerating and upgrading graphite from industrial production waste can be used by mixing it with resins of various types to create items and / or surface coverings of articles of rigid, semi-rigid or flexible materials, suitable to confer them unexpected mechanical, chemical and optical properties.

[0109] Preferably, the rigid, semi-rigid, flexible materials that are treated with the multifunctional semi-finished product are selected from the group comprising wood, metals, polymers, textile fibres, etc.

[0110] For example, the multifunctional semi-finished product can be used to make conductive components, as an insulator at certain temperatures, as a pigment on surfaces of wood, metal, fabric, plastic, etc., as a protective layer, and can be used as a lubricant or as an abrasive agent.

[0111] However, other ways and materials in which to use the multifunctional semi-finished product are not excluded.

[0112] Finally, being derived from unavoidable industrial waste, the multifunctional semi-finished product obtained allows to reduce waste and the costs for disposing of special waste.

[0113] From the foregoing, it appears that the method and plant of regenerating and upgrading graphite powder according to the invention achieve the intended purposes and in particular that of reducing the environmental impact of the graphite industry.

[0114] Although the device, the method and plant of regenerating and upgrading graphite powder have been described with particular reference to the attached figures, the reference numbers used in the description and in the claims are used to improve the intelligence of the invention and do not constitute any limitation to the scope of protection claimed.

[0115] Reference throughout the description to “one embodiment” or “the embodiment” or “some embodiments” indicates that a particular feature, structure or element described is included in at least one embodiment of the subject matter of the present invention.

[0116] Furthermore, the particular features, structures or elements may becombined in any suitable manner in one or more embodiments.Industrial applicability

[0117] The present invention is industrially applicable because it can be carried out on an industrial scale by industries belonging to the sector of the use of powdered graphite waste.

Claims

CLAIMS1. A method of regenerating and upgrading graphite from industrial production waste, comprising the provision of graphite powder of predetermined grain size obtained from the waste and treatment thereof with oily additives to reduce its dustiness and obtain a multifunctional semi-finished product, said semi-finished product being subsequently mixed with resins of various types to make items and / or surface coverings of articles of rigid, semirigid or flexible materials, suitable to confer them innovative mechanical, chemical and optical properties.

2. Method as claimed in claim 1 , wherein the rigid, semi-rigid or flexible materials constituting said items to be made or articles to be covered are selected from the group which comprises wood, metals, polymers, textile fibres.

3. Method as claimed in claim 1 , which comprises the following steps: a) collecting graphite powder obtained from waste at industrial processing sites; b) coarse filtering undifferentiated graphite powder to remove excess grain sizes and non-graphite waste subproducts from the powder; c) precision sieving to differentiate graphite powder into granulometries of predetermined value; d) treating the differentiated graphite powder in a controlled environment to obtain a regenerated and upgraded graphite powder with minimal air diffusion; wherein said phase d) of treatment comprises a sub-step of e) uniform distributing in hermetic conditions of particles of an oily additive in predetermined percentages over the differentiated graphite powders to obtain an intimate mixture of regenerated and upgraded graphite powders of granulometries and oily additive.

4. Method as claimed in claim 3, wherein said step e) of distributing in hermetic condition particles of an oily additive is carried out by spraying with an oily vapour.

5. Method as claimed in claim 3, wherein said predeterminedpercentages of distributing oily additive are in the range between 0.01 % and 15% by weight with respect to the total weight of the graphite powder.

6. Method as claimed in claim 3, wherein said oily additive is selected from the group of mineral oils comprising PHARMA H25.

7. Method as claimed in claim 3, wherein said granulometries of predetermined values are in the range between 500pm and 20pm and preferably in the range between 400pm and 30pm.

8. Method as claimed in claim 3, wherein said precision sieving is carried out by means of a vibrating sieve with combined jolting and rotary motion.

9. A plant (1) for regenerating and upgrading graphite powder from industrial production waste in application of the method according to one or more of the preceding claims, wherein said plant comprises:- a station for collecting graphite powder from industrial sites;- a hopper for collecting the filtered graphite powder;- a vibrating sieve (2) connected to said hopper to obtain powders of different granulometries;- an apparatus (5) for treating graphite powders of different granulometries comprising a mixer with a mixing chamber (6) and an electronic control unit (7);- a nebulization device (8) associated with said mixing chamber (6) and having a plurality of nozzles (13) for distributing an oily additive in a predetermined weight percentage on the graphite powders of different granulometries.

10. Plant as claimed in claim 9, wherein said vibrating sieve (2) has a hermetically sealed sieving chamber (3), configured to separate graphite powders having particles of different granulometries, said treatment apparatus (5) having weighing means for detecting a weighted quantity of differentiated graphite powder to be treated, introduction means (10) of said detected weighted quantity into said mixing chamber (6), dosing means (16) for dosing a weighted percentage of oily additive to be added to the weighted quantity ofdifferentiated graphite powders in said mixing chamber (6).11 . Plant as claimed in claim 10, wherein an interface is provided which is connected to said dosing means (16) and accessible by an external operator.

12. Plant as claimed in claim 11 , wherein said vibrating sieve (2) comprises within said sieving chamber (3) a series of stainless-steel filter nets with respective net tensioning rings.

13. Plant as claimed in claim 12, wherein said filter nets are operatively connected to an electric motor (4) to impart to said nets a combined jolting and rotary motion.

14. Plant as claimed in claim 13, wherein said nets have a substantially convex conical shape.

15. Plant as claimed in claim 9, wherein said nebulization device (8) comprises a tank (14) of oily additive connected to said plurality of spray nozzles (13) by means of a high-pressure pump (15).

16. Plant as claimed in claim 9, wherein said mixing chamber (6) comprises stirring means (12) for stirring the graphite powders sprayed with the oily additive to obtain an intimate contact between the fine particles of the powders and the droplets of nebulised oily additive.

17. Plant as claimed in claim 9, wherein said mixing chamber (6) comprises at least one discharge duct (11) communicating with a container (R) for collecting the regenerated and upgraded graphite powders.

18. Plant as claimed in claim 17, wherein in said discharge duct (11) there is provided a discharge valve which can be operated by command at the end of the mixing process.

19. Plant as claimed in claim 18, wherein said collection container (R) of the regenerated and upgraded graphite is removable upon filling thereof and is replaceable with an empty container for a new treatment cycle.

20. Method of use of a multifunctional semi-finished product obtained from the regeneration and upgrading of graphite powder from industrial production waste according to one or more of claims 1 to 9, by means of mixing said semi-finished product with resins of various types in order to create itemsand / or surface coverings of articles of rigid, semi-rigid or flexible materials, adapted to confer them innovative mechanical, chemical and optical properties.

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