PLANT AND PROCESS FOR THE RECOVERY OF WIRES FROM CAR FLUFF

Abstract

A plant for the treatment of car fluff is disclosed having one or more magnetic iron separators, followed by one or more eddy current separators that receive the negative coming from the magnetic iron separators, followed by one or more inductive sensor-based recovery separators that receive the negative coming from the eddy current separators, followed by at least two inductive sensor-based polishing separators respectively calibrated for the separation of stainless steel and copper wires arranged for receiving the material separated by the inductive sensor-based recovery separators, an unravelling shredder also being arranged between the latter and the polishing separator(s) calibrated for the separation of copper wires.

Claims

1. A car fluff treatment plant comprising: a) one or more magnetic iron separators; b) one or more eddy current separators that receive the negative coming from said magnetic iron separators; c) one or more inductive sensor-based recovery separators that receive the negative coming from said eddy current separators; d) at least two inductive sensor-based polishing separators respectively calibrated for the separation of stainless steel and of copper wires, said inductive sensor-based polishing separators being arranged to receive the material separated by said inductive sensor-based recovery separators wherein the plant further includes an unravelling shredder arranged between the inductive sensor-based recovery separators and the inductive sensor-based polishing separator(s) calibrated for the separation of copper wires.

2. The plant according to claim 1, wherein the unravelling shredder is a single-shaft or double-shaft shredder of the low-speed high-torque type, optionally with a power in the range of 75-120 KW.

3. The plant according to claim 1, wherein the unravelling shredder is provided with a clutch that stops it in case it receives a piece too hard to be processed therein.

4. The plant according to claim 1, wherein the unravelling shredder receives the negative coming from an inductive sensor-based polishing separator calibrated for the separation of stainless steel.

5. The plant according to claim 1, wherein the unravelling shredder receives the material separated by an inductive sensor-based recovery separator calibrated for the separation of copper wires.

6. The plant according to claim 1, wherein it further includes one or more aeraulic separators arranged immediately upstream from the magnetic iron separators and/or the inductive sensor-based recovery separators and/or the unravelling shredder.

7. A process for the treatment of car fluff with a plant according to claim 1 comprising: a) iron removal, by means of one or more magnetic separators; b) main recovery of non-ferrous metals, by means of one or more eddy current separators that treat the negative resulting from step a); c) recovery separation of residual non-ferrous metals, by means of one or more inductive sensor-based recovery separators that treat the negative resulting from step b); d) polishing separation of the material separated in step b), by means of at least one inductive sensor-based polishing separator calibrated for the separation of stainless steel; and e) polishing separation of the material separated in step c) or of the negative resulting from step b), by means of at least one inductive sensor-based polishing separator calibrated for the separation of copper wires; wherein it further includes a step d′) of breaking up by means of an unravelling shredder of the material to be treated in step e).

8. The process according to claim 7, further comprising a step of separation of the material into a light fraction and a heavy fraction by means of an aeraulic separator immediately before step a) and/or step c) and/or step d′).

9. The process according to claim 7, wherein step c) is divided into two sub-steps c′) and c″) in which the recovery of stainless steel and copper wires is carried out separately, by means of two or more inductive sensor-based recovery separators respectively calibrated for the separation of said materials.

10. The process according to claim 7, wherein the treated material has a size between 16 and 120 mm.

11. The process according to claim 7, wherein the treated material has a size between 40 and 120 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further advantages and characteristics of the plant and process according to the present invention will become apparent to those skilled in the art from the following detailed description of two embodiments thereof with reference to the accompanying drawings in which:

[0018] FIG. 1 is a flow diagram schematically showing a first embodiment of the invention; and

[0019] FIG. 2 is a flow diagram schematically showing a second embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Referring to FIG. 1 and to what was mentioned above about the stations/treatment steps, there is seen that a plant/process according to a first embodiment of the present invention conventionally includes in a first part magnetic iron separators and eddy current separators for the removal from car fluff of ferrous metals and Zorba, followed possibly by an aeraulic separator which divides the material between a light fraction containing waste material and a heavy fraction in which the copper wires and the pieces of stainless steel are concentrated to about 10% (this division into light and heavy fraction can have also take place before the iron removal at the beginning of the process).

[0021] The remaining material is then treated in a second part by at least one recovery separator and at least two polishing separators whose operating principle is based on the recognition of metal objects by means of an inductive sensors system and on the separation (ejection) of said metal objects by means of air jets, synchronized by an electronic system, which divert their trajectory and allow their physical separation from the treated material flow.

[0022] Note that an inductive sensor-based separator can be calibrated to separate only the copper wires or only the pieces of stainless steel or both simultaneously, in which case the work mode is defined all metals recovery. In the case where the separator is calibrated only for the separation of the copper wires the work mode is defined wire recovery, while in the case where it is calibrated only for the separation of pieces of stainless steel the work mode is defined Zurik recovery, with the term Zurik which corresponds to a concentrate of mixed metal with a prevailing presence of stainless steel according to the definition specified by the American association ISRI (Institute of Scrap Recycling Industries, www.isri.org).

[0023] Since the recovery separators and the polishing separators are of the same type, it is clear that the above-mentioned calibration alternatives and the definitions of the work modes are valid for both the recovery and the polishing steps, although in the latter step the material is usually treated only in Zurik polishing and wire polishing mode but not in all metals polishing mode.

[0024] Furthermore, it is obvious that the case of using multiple inductive sensor-based separators in a same station/step is understood to refer to separators positioned one after the other where each separator receives and works the negative of the previous separator, i.e. the fraction of material not ejected by the previous separator. This allows the further recovery of metals either missed by previous separators (in all metals recovery mode) or intentionally left by the preceding separator in the case of multiple separators calibrated in Zurik recovery/polishing or wire recovery/polishing mode that work in cascade.

[0025] Typically, the presence of copper wires and pieces of stainless steel in the Large fraction of the car fluff is respectively about 0.75% and 1% of the total, and the concentration of the copper wires and pieces of stainless steel present in the mixed metallic material recovered by the first recovery separator 1 is usually 45-65%. This material is then treated by at least one polishing separator 2 calibrated for the separation of pieces of stainless steel only (Zurik mode) to bring the concentration of these pieces of stainless steel to 85-95%. The negative, i.e. the fraction of the material that is not expelled by separator 2, normally is treated by at least one polishing separator 4 calibrated for the separation of copper wires only (wire mode) to bring their concentration to 70-80%.

[0026] To improve this result, the innovative aspect of the present invention relates to the addition of a unravelling shredder 3 between the polishing separators 2 and 4, so that separator 4 operates on a material free from wire tangles thus managing to obtain a concentration of wire ρ>90%.

[0027] The unravelling shredder 3 is advantageously of reduced size and cost given the limited amount of material that it must treat, approximately less than 2% with respect to the total of the car fluff and corresponding to 0.6% of the total value of the material entering the car shredder. For this purpose, therefore, a low-speed (less than 60 rev/min) and high-torque shredder is preferably used which can be single-shaft or double-shaft with counter-rotating shafts. The elements which act on the material to be treated are generally blades or hooked discs with a variable number of hooks, mounted on one or two shafts driven by an electric or hydraulic motor with a power of the order of 75-120 KW (an example of a suitable shredder is the DUAL-SHEAR® M85 of SSI Shredding Systems of Wilsonville, Oreg., USA).

[0028] Note that in unravelling a tangle of threads and inert material it could happen to release also a piece of stainless steel or other hard bulky material that had remained caught in the tangle, therefore shredder 3 is preferably also equipped with a clutch that stops it thus allowing the operator to remove the polluting piece without causing damage to the shredder. To limit such an occurrence there may also be provided an additional aeraulic separator 5, placed upstream from shredder 3, which divides the material between a sucked light fraction in which the copper wires are included and a heavy fraction containing the unwanted heavy pieces of stainless steel or other that could block shredder 3.

[0029] The second embodiment illustrated in FIG. 2 differs from the first embodiment only for the fact that the unravelling shredder 3, which is always immediately upstream from the polishing separator 4 for wires, instead of receiving the material from the polishing separator 2 for Zurik receives it from a recovery separator 1″ for wires. In fact in the recovery station/step the material is not treated in all metals recovery mode but rather first by a recovery separator 1′ in Zurik recovery mode and then by a recovery separator 1″ in wire recovery mode.

[0030] Therefore from the first separator 1′ there is directly obtained Zurik with ρ=45-65% which is then treated in a polishing separator 2 for Zurik bringing it to a concentration ρ=85-95%, while from the second separator 1″ there is obtained the material containing the wires that is sent to the unravelling shredder 3 (with possible passage through aeraulic separator 5) before being treated in the polishing separator 4 for wires.

[0031] The steps of the process for the treatment of car fluff carried out in the plant described above can therefore be summarized as follows:

a) iron removal, by means of one or more magnetic separators;
b) main recovery of non-ferrous metals, by means of one or more eddy current separators that treat the negative resulting from the preceding step;
c) recovery separation of residual non-ferrous metals, typically stainless steel and copper wires, by means of one or more inductive sensor-based separators that treat the negative resulting from the preceding step;
d) polishing separation of the material separated in the previous step, by means of at least one inductive sensor-based separator calibrated for the separation of stainless steel;
e) breaking up of the material separated in step c) or of the negative resulting from the preceding step, by means of an unravelling shredder;
f) polishing separation of the material broken up in the preceding step, by means of at least one to inductive sensor-based separator calibrated for the separation of copper wires.

[0032] The method may further comprise a step of separation of the material into a light fraction and a heavy fraction by means of an aeraulic separator immediately prior to step a) and/or step c) and/or step e). The step c) can also be divided into two sub-steps c′) and c″) in which the recovery of stainless steel and copper wires is carried out separately.

[0033] It is obvious that the embodiments of the plant/process according to the invention described and illustrated above are just examples susceptible of various modifications. In particular, the exact number, type and arrangement of the inductive sensor-based separators can vary depending on the specific application, e.g. the order in the sequence of recovery separators 1′, 1″ can be reversed.