The present invention concerns the recovery of metals from scrap, and in particular an apparatus for the recovery of copper from electrical wires and electric motors recovered from the material called car fluff.

As is well known, at the end of their life, cars, and also other large industrial and domestic products of essentially ferrous composition, are ground with large hammer mills (so-called car shredders) which reduce them to pieces of less than 150 mm in size in order to obtain ferrous scrap. On leaving these mills, the ground mixed material undergoes an action of iron removal by means of large electromagnetic drums in order to recover and clean up the ferromagnetic steel.

What is discarded by these electromagnetic drums, called car fluff is essentially composed of plastics, rubbers, polyurethane foams, glass, aluminium, copper, zinc, zinc alloys, lead, stainless steel, electrical wires, stone residues, iron oxides and some ferromagnetic steel lost during the iron removal action. The hanks of electrical wires are recovered by means of inductive sensors separators and then passed through a hammer mill to open the hanks and free the wires from hard elements, such as pieces of stainless steel, which would create problems for further processing of the material with fast knife mills.

The material coming out of the hammer mill falls onto a vibrating table in a well- opened and freed condition and is processed by a magnetic separator, such as a magnetic pulley or drum, but could also be an overbelt separator, to remove ferromagnetic pieces. In a subsequent step, the resulting material is processed in an aeraulic gravimetric separator that separates between a light fraction (containing the copper wires) and a heavy fraction, comprising all other solid and heavy pieces that precipitate. In this way, in the subsequent steps of wire processing using knife mills, for the release of the copper fraction from the insulating polymer sheaths, these mills are not affected by the presence of heavy and hard elements that would otherwise damage their blades, resulting in significant maintenance time and costs.

Traditional aeraulic separators operate as stand-alone machines and can be either simple or zig-zag type air stream screens, or cyclonic separators. In the first type, the air stream is emitted horizontally at the base of a vibrating feed chute, so that the heavy fraction falls immediately in front of the chute by gravity, the light fraction is carried away by the air stream and then removed by suction, and an intermediate fraction is only displaced by the air stream and falls in a more distant position, past a separator that separates it from the heavy fraction. In the zig-zag variant, the air flow is introduced horizontally at the base of a vertical zig-zag channel in which the material to be separated is loaded from above, so that the heavy fraction falls by gravity while the light fraction is carried away by the countercurrent air flow. Examples of these types of separators are, respectively, the Wind Sifter QSS and the Wind Sifter ZZS manufactured by Trennso- Technik Trenn- und Sortiertechnik GmbH (Weissenhorn, Germany).

US 2012/0048974 describes a plant for the treatment of municipal solid waste comprising a number of devices, including gravimetric separators followed by magnetic separators operating on intermediate streams of material that has previously undergone various comminuting, size fractioning and density fractioning steps. US 10131507 describes a hood for transferring from a first conveyor belt to a second conveyor belt an air stream containing light material to be sorted, the hood comprising at least one exit passage for discharging a portion of the conveying air stream.

The traditional procedure for recovering copper wires from car fluff described above therefore requires the use of three different types of separator (i.e. inductive sensors, magnetic and aeraulic) with the consequent drawbacks in terms of cost and space, as well as time and manpower for transferring the material from one separator to the other.

The purpose of the present invention is therefore to provide an apparatus that partially overcomes the aforementioned drawbacks. This purpose is achieved by means of an apparatus which processes in a single pass the mixed wires recovered from car fluff by the inductive sensors separator, thanks to the combination of a magnetic separator and an aeraulic separator in a single apparatus which performs both types of separation simultaneously.

The fundamental advantage of this apparatus is therefore that it reduces the number of necessary apparatuses and processing steps from three to two, with obvious savings in terms of cost, space, time and labour.

Another important advantage of the above-mentioned apparatus is its structural simplicity and low cost, which make it reliable and also suitable for integration into existing systems.

Further advantages and features of the apparatus according to the present invention will be apparent to those skilled in the art from the following detailed description of an embodiment thereof with reference to the accompanying drawings, wherein:

Fig.l is a longitudinal sectional view showing schematically the structure of the apparatus; and

Fig, 2 is a perspective view of the section of Fig.l.

Referring to the aforementioned figures, it can be seen that an apparatus according to the present invention provides, as a first separator, a magnetic separator comprising a magnetic pulley 1 which receives the material fed through an upper inlet E, where a vibrating chute 2 distributes it on a conveyor belt 3 dragged by pulley 1. In this way, the ferromagnetic pieces remain adhered to pulley 1 when the conveyor belt 3 rotates around it, and detach when they move away along the lower branch of the conveyor belt 3 falling towards a first lower outlet M located below it, preferably extending from pulley 1 to about one third of the conveyor belt 3.

The non-magnetic material, on the other hand, falls from the conveyor belt 3 as soon as it wraps around pulley 1, and is hit by a jet of air from an aeraulic separator arranged substantially below the magnetic separator in such a way as to minimise the footprint. The two separators, magnetic and aeraulic, are placed in a single housing that encloses them both to form a single, more compact and economical unit.

The aeraulic separator comprises a fan 4, an air supply duct 5 and a delivery nozzle 6 arranged adjacent to pulley 1, below the non-magnetic material fall path. The nozzle 6 is preferably inclined at an upward angle of between 40° and 70°, more preferably about 55°. In this way, the light fraction is thrown past an inclined separator 7, arranged on the opposite side of the fall path from nozzle 6, falling by gravity preferably through a second lower outlet L, located between the inclined separator 7 and the end of housing 8. The heavy fraction simply falls by gravity before separator 7, preferably through a third outlet H located below it.

Furthermore, preferably, the air delivery nozzle 6 and/or separator 7 are adjustable in inclination to adapt the apparatus to the characteristics of the material being treated, so as to achieve optimal separation of the light fraction from the heavy fraction.

By way of example, an apparatus according to the invention could have the following characteristics:

- 0310 mm magnetic pulley in neodymium grade N50 - Conveyor belt speed 1-2 m/s

- Total apparatus dimensions: length 4 m, width 1.5 m, height 1.8 m

- Total weight 2500 kg

- Conveyor belt thickness 6.9 mm in 3 layers

- Machine table width 1000 mm - Conveyor belt motor power 3 kW

- Fan motor power 15 kW

- Inverter to adjust both magnetic pulley and fan speed