GB2624737A

GB2624737A - Method and system of processing a flow of waste material

Info

Publication number: GB2624737A
Application number: GB2311431.7A
Authority: GB
Inventors: Bryan Simon; Paston Derek
Original assignee: European Metal Recycling Ltd
Current assignee: European Metal Recycling Ltd
Priority date: 2023-07-26
Filing date: 2023-07-26
Publication date: 2024-05-29
Also published as: GB202311431D0

Abstract

Method 1 of processing waste comprising a first separation stage 2 transporting a flow of material 5 along a mechanical path 6, a first rotating drum 7 adjacent the path to magnetically collect a first output of ferrous material, a second separation stage 3 comprising transporting the first output material along a flow path 9, a second rotating drum 11 adjacent the path 9 to magnetically collect a second output of ferrous material. Each separation stage 2 3 has different separation characteristics such that the output of the first stage 2 is different to the output of the second stage 3. The rotating drums 7 11 comprise a rotatable shell and a stationary magnet within the shell. The stationary magnet of the first rotatable drum 7 has a greater strength than the stationary magnet of the second rotatable drum 11. The first 6 and second 8 flow paths may comprise vibrating conveyors. There may be a third separation stage comprising a third drum magnet comprising a rotatable shell and stationary magnet. A corresponding system is disclosed.

Description

Method and System of Processing a Flow of Waste Material

FIELD

The present teaching relates to a method and a system of processing a flow of waste material.

BACKGROUND

Global efforts to reduce the generation of waste has seen a rise in recycling processes.

Recycling helps to reduce the need for landfill and other expensive means of disposal. Recycling also reduces the need for extracting and processing new raw materials, creating a more circular economy, while also reducing energy consumption, as well as air and water pollution associated with the generation of raw materials.

Waste materials often contain valuable metals that can be recovered and recycled. Ferrous and non-ferrous metals are typically found in mixed waste streams. Some of these materials may be highly sought after when recycling waste. Ferrous metals, such as iron and steel, have a high scrap value but are difficult to obtain at a desired purity. Non-ferrous metals, such as aluminium, copper and brass also have a high value, but are often difficult to separate from ferrous materials.

Processing waste material to extract valuable metals from other waste materials can be costly and complex. Traditional methods include physical processes such as sorting and crushing, as well as chemical processes such as leaching and smelting. While the latter methods can be effective, they are energy-intensive and produce harmful emissions.

Moreover, such techniques often fail to obtain the desired purity of metal required for reuse. In some sectors, a common standard required purity of scrap steel and iron can be between 96-98%. In other applications, for example in the use of high-grade steels and alloys, the purity requirements can be as high as 99.5% or more. Such a high purity can be difficult and energy intensive to obtain, often making the processing of waste materials uneconomical, and resulting in valuable waste being landfilled.

The present teachings seek to overcome or at least mitigate one or more problems

associated with the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a method of processing a flow of waste material, the method comprising: a first separation stage comprising transporting a flow of waste material along a first flow path, wherein a first rotating drum is arranged adjacent the first flow path and is configured to magnetically collect a first output of material from said flow, the first output comprising ferrous material; a second separation stage comprising transporting the material from the first output along a second flow path, wherein a second rotating drum is arranged adjacent the second flow path and is configured to magnetically collect a second output of material from the first output, the second output comprising ferrous material; wherein each separation stage is configured with a separation characteristic different from the other such that the ferrous content of the first output is different from the ferrous content of the second output.

Advantageously, the method set forth has been found to be useful for effectively separating potentially valuable ferrous materials from materials with less value that may be present in a flow of waste material. The use of two rotating drums as set forth to magnetically collect materials has been found to provide a better overall separation of ferrous material.

In exemplary embodiments, the method can be configured so that the first rotating drum provides an initial screening of the waste material, while the second drum collects ferrous from the initially screened output.

In exemplary embodiments, the method is configured for separating a flow of waste containing many different types of materials, including ferrous metals, non-ferrous metals, non-metals e.g. in varying proportions. Some of the material may form "clumps" while being processed, and thus some ferrous material may be clumped with non-ferrous or non-metal materials. As such, it can be complex to obtain a near-pure extraction of ferrous in a single processing step.

The improved process is beneficial in increasing the value of products extracted from the waste material. For example, the ferrous material obtained may have minimal impurities, allowing it to be re-used in new products requiring ferrous materials.

Improving the process of separating waste is essential for the viability of recycling, which in turn reduces the need for extraction and fabrication of new raw materials, which can be energy intensive and have a high carbon footprint. Moreover, improving the viability of recycling processes is critical in reducing waste generation, and the associated landfill or other waste treatment processes which have negative environmental impacts.

In exemplary embodiments, the first and second rotating drums are first and second drum magnets, each comprising a rotatable shell and a stationary magnet within the rotatable shell. The separation characteristic of each stage is a function of at least the strength of each respective stationary magnet, and wherein the stationary magnet of the first rotating drum has a greater strength than the stationary magnet of the second rotating drum.

Utilising the strength of each magnet has been found to be an effective way of selectively separating the flow of waste material into the first and second outputs. More specifically, the strength of the magnets can influence the type of materials collected by each rotating drum, since the stronger magnet can collect a large amount of ferrous material compared with the weaker magnet.

In a magnetic separation, some ferrous material will avoid separation/collection by the drum if the magnet is not strong enough (e.g. the magnet may not generate enough upward force to overcome the downward force of the material's weight).

As such, configuring the magnet of the first rotating drum in this way advantageously serves to extract as much ferrous as possible from the flow of waste material in the first separation stage to transport to the second separation stage for further processing, or fine tuning. It has been found to be advantageous for the magnet of the second rotating drum to have a lower comparative strength, in order to be more selective about the type of ferrous material that it collects.

In exemplary embodiments, the magnet of the first rotating drum has a greater Gauss than the magnet of the second rotating drum at a respective drum surface.

Advantageously, configuring the drums as such has been found to improve the separation of the flows and improve the purity of the final products. The term "purity" used herein is intended to relate to the concentration of ferrous materials in the final product, e.g. higher purity means that less impurities (e.g. copper) are present in the products.

In exemplary embodiments, the magnet of the first rotating drum is configured to generate a Gauss in the range 400 to 3000 G at a surface of the first drum. Preferably, the magnet of the first rotating drum is configured to generate a Gauss in the range 800 to 3000 G at a surface of the first drum, preferably in the range 1500 to 2500G. more preferably in the range 1500 to 2000 G, more preferably in the range 1800 to 2000 G. In exemplary embodiments, the magnet of the first rotating drum is configured to generate a Gauss of 1900 G at a surface of the first drum.

Operating the magnet of the first drum at a Gauss of 1900 G has been found to improve the extraction of ferrous material from the flow in the first separation stage, thus minimising loss of ferrous in the first stage and maximising the yield of the method.

In exemplary embodiments, the magnet of the second rotating drum is configured to generate a Gauss in the range 100 to 2000 G at a surface of the second drum. Preferably, the magnet of the second rotating drum is configured to generate a Gauss in the range 200 to 1500 G at a surface of the second drum, more preferably in the range 300 to 1300 G (e.g. 325 G, 1220 G).

In exemplary embodiments, the magnet of the second rotating drum is configured to generate a Gauss in the range of 500 G to 1200 G at a surface of the second drum, more preferably in the range of 700 G to 1000 G, more preferably in the range of 850 G to 950 G. In exemplary embodiments, the magnet of the second rotating drum is configured to generate a Gauss of 910 G at a surface of the second drum.

Operating the second drum magnet at a Gauss of 910 G has been found to be particularly preferable in improving the separation obtained in the second step, and thus improving the overall separation.

In exemplary embodiments, the flow path is a mechanical flow path.

In exemplary embodiments, the separation characteristic of each stage is a function of at least the relationship between the speed at which each respective drum rotates and a movement speed of the respective flow path.

It has been found that the speed of the drum relative to the movement speed of the flow path can advantageously be adapted to influence the exposure of ferrous material to the magnetic field of the respective magnet.

The speed of the drum can be advantageously adapted to influence the separation of materials. In particular, the speed of the drum relative to the speed of the flow path has an impact on the surface area of the drum that is available to collect ferrous material from a respective flow path (i.e. if the speed of the drum relative to the flow path increases then there is more available surface area presented to the flow path).

The speed of the flow path relative to the speed of the drum can be adapted to also influence the surface area of the drum available. Specifically, reducing the speed of the flow path relative to the drum results in material approaching the drum more slowly, thereby reducing the rate at which ferrous material is moved to the drum surface, meaning there is more available surface area presented to the flow path.

In some applications, altering the speed of the drum by operating the drum at a faster speed and/or reducing the flow path speed increases the available surface area of the drum, and so increases the likelihood that ferrous material will be collected by the drum, thus improving the purity of the final products.

In exemplary embodiments, the first drum is configured to rotate at greater speed relative to the speed of first flow path compared with the speed of the second drum relative to the speed of the second flow path.

In this way, the first drum has a greater surface area available to the material on the flow path, thereby increasing the likelihood that ferrous material will be collected by the first drum. In such an embodiment, the first drum can be seen as providing a "coarse" separation, i.e. extracting as much ferrous material as possible via the stronger magnet, while the second drum can be utilised to fine tune the output of the first drum via the weaker magnet.

Such an arrangement is particularly advantageous when the first magnet has a greater strength than the second. In this way, the first drum provides a coarse extraction, while the second drum acts as a fine tuner.

In exemplary embodiments, the first drum is configured to rotate at a speed in the range of 1 to 20 RPM (e.g. 1 RPM, 2 RPM, 3 RPM, 4 RPM, 5 RPM 6 RPM, 7 RPM etc.), preferably in the range of 5 to 15 RPM, preferably in the range of 8 to 12 RPM, more preferably in the range of 9 to 11 RPM.

In exemplary embodiments, the first drum is configured to rotate at a speed of 10 RPM.

In exemplary embodiments, the first flow path is configured to operate at a speed in the range of 0.1 and 1 m s-1, preferably in the range of 0.1 and 0.5 m s-1, more preferably in the range of 0.2 and 0.4 m s.

In exemplary embodiments, the first flow path is configured to operate at a speed of 0.3 m s.

Operating the first drum at 10 RPM and the first flow path at 0.3 m s-1 has been advantageously found to increase the amount of ferrous collected by the first drum, thereby reducing loss of valuable material.

In exemplary embodiments, the second drum is configured to rotate at a speed in the range of 10 to 30 RPM (e.g. 10 RPM, 11 RPM, 12 RPM etc.), preferably in the range of 10 to 25 RPM (e.g. 11.5 RPM, 23 RPM), more preferably in the range of 15 to 20 RPM.

In exemplary embodiments, wherein the second drum is configured to rotate at a speed of 19 RPM.

In exemplary embodiments, the second flow path is configured to operate at a speed in the range of 0.5 and 5 m s-1, preferably in the range of 1 and 3 m s 1, (e.g. 1 m s 1, 1.18 m 1.5 m s_1, 2 m s ', 2.35 m s ', 2.5 m sl, 3 m s 1), more preferably in the range of 1 and 2 m s-1, more preferably in the range of 1.4 and 1.7 m s.

In exemplary embodiments, the second flow path is configured to operate at a speed of 1.65 m Operating the second drum at a speed of 19 RPM and the second flow path at 1.65 m has been found to improve the selectivity of the second drum and increase the purity of the final product.

In exemplary embodiments, the first and second rotating drums are first and second drum magnets, each comprising a rotatable shell and a stationary magnet within the rotatable shell.

In exemplary embodiments, the separation characteristic of each stage is a function of at least a direction of rotation of the respective rotatable shell about a respective longitudinal axis of each drum magnet.

The direction of rotation of the shells can be used to control the influence of gravity on the separation of each step, and thus the influence mass or density of material has on the overall separation.

In some embodiments, the flow of waste material contains various different types of materials having different densities, and therefore mass. Increasing the influence of gravity on the separation can facilitate separation based on mass (and thus density), in addition to magnetism.

In some embodiments, a large proportion of the flow of waste material is the same type of material (e.g. steel), thus large proportions of the material have the same density. For example, some of the material may be in the form of sheet metal, having a higher volume and thus a lower mass. Some of the material may be in the form of lumps of metal (e.g. a solid block), that has a lower volume and thus a higher mass. In this way, increasing the influence of gravity on the separation may increase the likelihood that the lighter metal (e.g. sheet metal) is collected, and the heavier metal (e.g. metal lumps) falls under gravity. As such, the feed material can be separated based on both mass and magnetic properties.

The direction of rotation can be adaptable in some embodiments so as to facilitate operator control over how the material should be separated.

In exemplary embodiments, the direction of rotation of the shell of the first drum magnet is such that the first output is collected by and flows over the first drum magnet.

In exemplary embodiments, the direction of rotation of the shell of the second drum magnet is such that the second output is collected by and flows over the second drum magnet.

In exemplary embodiments, the shell of the second drum magnet rotates in the same direction as the shell of the first drum magnet.

Advantageously, the outputs can be lifted over the drum, such that the magnetism of the material is the key component that the separation is based on. For the first separation stage, such a rotational direction maximises the amount of ferrous carried over to the second separation (i.e. more dense material is less likely to fall away under gravity once engaged with the drum, since the material flows over the drum and is therefore supported by the drum), so as to provide an initial screening and minimise loss of potentially valuable ferrous in the first stage.

In exemplary embodiments, the separation characteristic of each stage is a function of at least a relative position of the respective magnet within the shell.

Utilising the position of the magnet within the shell has been found to increase the flexibility of the process to base the separations on magnetism and/or mass or density. This can improve the value of the output since the properties (e.g. magnetic properties as well as density and mass) of each output stream can be adjusted based on operational requirements.

In exemplary embodiments, the first drum magnet is configured such that the respective magnet is positioned within the shell so as to be adjacent the first flow path.

In exemplary embodiments, the second drum magnet is configured such that the respective magnet is positioned within the shell so as to be adjacent the second flow path.

Positioning the magnets in such a way assists in collecting large amounts of ferrous material, thereby preventing significant loss of valuable material that may be more difficult to be collected by the drum (e.g. material that is clumped with other, non-ferrous material, or because material that is more dense/heavy). Such an arrangement prevents significant loss of valuable material and improves the overall efficiency of the separation.

In exemplary embodiments, each of the first and second drums are configured to be spaced apart from the respective first and second flow paths so as to define a respective first and second clearance between the drum and the flow path, and wherein the separation characteristic of each stage is a function of at least the respective clearance.

Utilising the clearance between the drums and the flow paths has been found to be an effective way of influencing the separation of the waste material. In particular, the clearance between the drum and the flow path can be selected to assist with separation based on not only magnetic properties of the waste material (i.e. ferrous vs non-ferrous) but also separating based on the mass or density of the material (i.e. the weight). In this way, the separation may be adapted such that only lighter ferrous materials are collected by the drum (meaning that heavier materials are not collected).

Such an arrangement has been found to be particularly advantageous for the second separation stage, wherein separation of the ferrous material collected in the first separation stage can be fine-tuned. In exemplary embodiments, the second stage can fine tune the output of the first stage into a separation of lighter, purer ferrous being collected by the second drum, with heavier, less-pure ferrous not being collected.

In exemplary embodiments, the flow paths are provided as a moving surface along which the material is transported, i.e. a mechanical flow path with a surface that moves so as to translate material thereon from one location to another.

In exemplary embodiments, the first flow path is provided by a first conveyor, and the second flow path is provided by a second conveyor.

It should be understood that the term "conveyor" used herein can be interchanged with any moving surface along which material is transportable (e.g. a conveyor belt or the like).

In exemplary embodiments, the separation characteristic of each stage is a function of at least a surface speed of a respective conveyor or mechanical flow path.

In exemplary embodiments, the second conveyor is configured to operate at a greater speed than the first conveyor.

Advantageously, the greater speed of the second conveyor serves to provide a thinner layer of material on the second conveyor, since the second conveyor will be moving at a greater speed when the first output is introduced to the second conveyor from the first drum. In this way, material of the first output that is on the second conveyor is less likely to pile up, and instead will be dispersed more evenly across the surface of the second conveyor (i.e. compared to the arrangement of material on the first conveyor, which is generally less distributed).

Such an arrangement is preferable when the strength of the first drum magnet is greater than the second. Specifically, the first separation stage acts as the initial screening, with the second separation stage acting to "fine tune" the output from the first stage. The improved dispersion of material on the second flow path thereby improves the selectivity of the second separation, i.e. because material is less likely to be erroneously collected by way of being piled or clumped. As such, the combination of the strength of the magnets and the speed of their respective flow paths can assist in the separation obtained in the second stage, and thus improving the quality (e.g. the purity) of the final product.

The relative speed of the first rotating drum can also assist in promoting the introduction of material to the second conveyor in a more dispersed form, i.e. the speed of the first rotating drum influences the speed at which the material is introduced to the second conveyor.

A thinner and more evenly dispersed layer of material can improve the effectiveness of the second separation stage, since the material is introduced to the second drum in a more singular form (i.e. less likely to be clumped or piled up), and so it is less likely that material will be erroneously collected/not collected by the second rotating drum.

Such an arrangement can thus improve the purity of the resulting output, thus increasing the value of the final product and improving the effectiveness of the recycling process.

The arrangement set forth is particularly advantageous when the stationary magnet of the first rotating drum has a greater strength than the stationary magnet of the second rotating drum. In this way, the first rotating drum can collect a large amount of material, including as much ferrous as possible, for fine tuning in the second stage. Having the second conveyor at a greater speed allows the material to be more evenly distributed when exposed to the second drum, resulting in a more effective extraction of ferrous material, and thus a purer product.

In exemplary embodiments, at least the first conveyor is configured to vibrate, so as to disperse the waste material on the first conveyor.

Advantageously, the vibration of the first conveyor serves to reduce the pile-up of waste material on the first conveyor. Rather, the waste can be more effectively distributed across the conveyor to reduce the presence of clumps of material and improve the effectiveness of the first separation stage.

In exemplary embodiments, the second conveyor is configured to vibrate.

In exemplary embodiments, the first separation stage produces the first output and a third output from the flow of waste material. The third output is defined by material remaining in the flow of waste materials after the first output is magnetically collected.

In exemplary embodiments, the separation characteristic of the first separation stage is configured such that the third output comprises substantially zero ferrous material.

Advantageously, the first separation stage can be seen as an initial extraction of as much ferrous as possible from the waste material, without being overly concerned by the presence of any non-ferrous in the first output. As such, in exemplary embodiments, the first output will include a majority of ferrous, but also many undesirable contaminants (e.g. hybrids, clumps, non-metals and non-ferrous that is collected along with the flow of ferrous collected by the first rotating drum). Such an arrangement reduces the likelihood that any valuable ferrous material is lost during the first separation stage.

It should be understood that no separation is perfect, and so the third output will contain some ferrous material. As such, "substantially zero" should be taken to mean that a negligible fraction of the third output contains ferrous material that was not magnetically collected by the first drum (e.g. it may have been clumped with a large non-ferrous or non-metal material).

In exemplary embodiments, the first flow path and first rotating drum are arranged such that the third output falls from the first flow path under gravity after the first separation stage.

In exemplary embodiments, the second separation stage produces the second output and a fourth output from the first output of material. The fourth output is defined by material remaining in the first output after the second output is magnetically collected.

In exemplary embodiments, the separation characteristic of the second separation stage is configured such that the fourth output comprises ferrous material and non-ferrous material, and such that the ferrous material in the second output is less dense or lighter (e.g. has a lower average mass) than the ferrous material in the fourth output.

It should be understood that reference to the density or mass of an output is not in relation to the output as a whole, but rather relates to the average density or mass of ferrous material in the output. In this way, the fourth output can be seen as mostly containing ferrous material that has a higher mass/density (e.g. solid blocks of material), whereas the second output can be seen as mostly containing ferrous materials of a lower mass/density (e.g. sheet material).

Advantageously, while the second drum is configured to collect a significant amount of ferrous material and thus the material collected by the drum is further refined, the drum is also configured such that the ferrous material itself is separated based on the density or the mass of the ferrous material.

Separating in this way means that the "lighter" materials (i.e. less mass) in the second output can be processed separately from the "heavier" materials (i.e. greater mass) in the fourth output. Processing in this way means the ferrous material itself can be separated for re-use in different applications, for example, heavier ferrous (e.g. cast iron, steel lumps) that is difficult for a magnet to collect can be collected separately in the fourth output.

As such, the final product from the process is purer and can be sub-divided into different types of ferrous materials.

It should be understood that the outputs of each separation stage include multiple component parts. The method is configured such that the component parts of each output collectively possess chemical properties that are different to the component parts of another output. Put another way, if the component parts of one output were melted down and turned into an alloy, such an alloy would be chemically different than a respective alloy formed from another output.

In exemplary embodiments, the second flow path and second rotating drum are arranged such that the fourth output falls from the second flow path under gravity after the second separation stage.

In exemplary embodiments, the method further includes: a third separation stage comprising transporting the material from the fourth output along a third flow path, wherein a third rotating drum is arranged adjacent the third flow path and is configured to magnetically collect a fifth output of material from the fourth output, the fifth output comprising ferrous material; wherein the third separation stage has a separation characteristic different from that of the first and second separation stage other such that the ferrous content of the fifth output is different from the ferrous content of the first and second output.

Advantageously, the fourth output (i.e. the material not magnetically collected by the second rotating drum) can be further processed to further refine the product, as the fourth output may contain ferrous material that has not been extracted in the first and second separation stages (e.g. ferrous material that is particularly dense or heavy).

In exemplary embodiments, the third rotating drum is a third drum magnet having a rotatable shell and a stationary magnet within the rotatable shell.

In exemplary embodiments, the separation characteristic of the third separation stage is a function of at least the strength of the stationary magnet of the third rotating drum.

In exemplary embodiments, the stationary magnet of the third rotating drum has a greater strength than the stationary magnet of the second rotating drum.

In exemplary embodiments, the magnet of the third rotating drum has a greater Gauss than the magnet of the second rotating drum at a respective drum surface.

In exemplary embodiments, the magnet of third rotating drum is configured to generate a Gauss in the range of 100 to 3000 G at a surface of the third drum (e.g. 210 G, 770 G), preferably in the range of 500 to 2500 G, more preferably in the range of 1000 to 2000 G, more preferably in the range of 1500 to 1800 G. In exemplary embodiments, the magnet of the third rotating drum is configured to generate a Gauss of 1700 G at the surface of the drum.

Operating the third rotating drum at such a magnetic strength has been found to be particularly advantageous at facilitating the drum collecting particularly dense or heavy ferrous materials from the fourth output (i.e. because the strength is high enough to overcome the downward force of gravity). In particular, having the third magnet be stronger than the second facilitates the second magnet acting to separate out a more lightweight ferrous and the third magnet acting to separate out a more heavyweight ferrous, in this way, the chemistry of the outputs from each stage can be different, allowing different uses of the final product and reducing the need for downstream separation of the ferrous into different types of ferrous.

In exemplary embodiments, the separation characteristic of the third separation stage is a function of at least relationship between the speed at which the third drum rotates and a movement speed of the third flow path.

In exemplary embodiments, the third drum is configured to rotate at a speed in the range of 10 to 30 RPM (e.g. 10 RPM, 11 RPM, 12 RPM, 12.3 RPM, etc.), preferably in the range of 15 to 25 RPM (e.g. 24.6 RPM), more preferably in the range of 20 to 25 RPM.

In exemplary embodiments, the third drum is configured to rotate at a speed of 21 RPM.

In exemplary embodiments, the third flow path is configured to operate with a surface speed in the range of 0.5 and 5 m s-1, preferably in the range of 1 and 3 m s-1, (e.g. 1 m s-1, 1.5 m s1,2 m 51 2.5 m s-1, 3 m s1), more preferably in the range of 1 and 2.5 m s-In exemplary embodiments, the third flow path is configured to operate with a surface speed of 1.8 m 5-1.

In exemplary embodiments, the third drum is configured to rotate at greater speed relative to the speed of third flow path compared with the speed of the second drum relative to the speed of the second flow path.

In this way, the third drum has a greater surface area available to meet the material on the third flow path (i.e. compared with the second drum). This is particularly important when the third drum has a higher strength than the second drum, as the third drum provides a more effective separation of difficult-to-separate substances, i.e. substances that are particularly heavy.

In exemplary embodiments, the third flow path is in the form of a third conveyor (or any device with a moving surface along which material is transportable).

In exemplary embodiments, the separation characteristic of the third separation stage is a function of at least a surface speed of a respective conveyor.

In exemplary embodiments, the third conveyor is configured to operate at a greater speed than the second conveyor.

Advantageously, the greater speed of the third conveyor allows even greater distribution of the fourth output on the third conveyor, thereby improving the ease at which the material in the fourth output can be liberated from the flow path (i.e. because the material is less likely to be clumped). Such a configuration is particularly advantageous when the third separation stage is intended to process particularly dense and heavy ferrous material that is typically difficult to liberate (e.g. because the third magnet is stronger than the second magnet).

In exemplary embodiments, the separation characteristic of the third separation stage is a function of at least a clearance between the third drum and the third flow path.

In exemplary embodiments, the separation characteristic of the third separation stage is a function of at least a direction of rotation of the shell of the third drum magnet about a longitudinal axis of the drum magnet.

In exemplary embodiments, the separation characteristic of the third separation stage is a function of at least a relative position of the magnet within the shell.

In exemplary embodiments, the direction of rotation of the third drum magnet is such that the fifth output is collected by and flows under the third drum magnet.

Advantageously, the arrangement has been found to reduce the amount of non-ferrous material being collected by the drum. Specifically, since the material has to move under the drum during the separation stage, the downward force of gravity on the material is in conflict with the upward force from the magnet. In exemplary embodiments, if material has erroneously been collected by the drum (for instance because it is a non-ferrous material clumped with another ferrous material), then it is likely to fall under gravity before it is moved to the final output with the ferrous material. As such, the purity and thus value of the final product is improved.

Positioning the third magnet in this way is particularly effective when used in combination with the positioning of the first and second magnets, since the third separation stage requires the force of magnetism to overcome the force of gravity acting on material in the flow of material. The third stage, therefore, does not erroneously collect a significant portion of non-ferrous, meaning the final product is purer.

In exemplary embodiments, the third drum magnet is configured such that the magnet is positioned within the shell so as to be adjacent a surface of the shell proximal to ground level.

Advantageously, positioning the magnet in such a way assists in separating the fourth output based on its magnetic strength. Since the magnet is closer to ground level, and the shell rotates to take the collected material thereunder, the material will attract to a lower surface of the shell and so will be exposed to the force of gravity. As such, any material that has been erroneously collected by the third magnet will be more likely to fall under gravity before being fed to the final output with the fifth output. The arrangement has been found to improve the purity of the final product.

In exemplary embodiments, the method includes a pre-treatment step, wherein the flow of waste material is shredded, ground, or otherwise fragmented before being transported along the first flow path.

Advantageously, shredding, grinding, or fragmenting the flow of waste material reduces its particle size. This reduces the likelihood that material will clump together and be mistakenly collected/not collected by any of the separation steps. Having the ferrous material in the form of smaller particles has been found to increase the ease at which the drums magnetically collect the material, as the smaller particles are easier to liberate from the flow of waste material. The greater surface area to weight ratio of the waste improves the efficiency of the overall separation, and thus the purity of the final product.

In exemplary embodiments, the pre-treatment step further comprises a screening step in which the shredded, ground or fragmented waste material is screened by a grid having a plurality of apertures before being transported along the first flow path.

Advantageously, it has been found that the screening ensures the material is shredded, ground or fragmented to a suitable size for separation, thereby facilitating effective separation of the material.

In exemplary embodiments, the apertures have an area of 150 mm by 150 mm.

The specific aperture size has been found to provide waste at an optimum size for the separation. While reducing the particle size further may result in improved liberation of ferrous material, shredding, grinding or fragmenting the waste material is an expensive process. As such, this aperture size has been found to provide the optimum balance between reducing price whilst ensuring good liberation of the ferrous material.

In exemplary embodiments, the pre-treatment step further comprises a cleaning step, in which the shredded, ground or fragmented waste material is cleaned such that contaminants can be removed from the waste material before transporting the material along the first flow path.

Advantageously, the cleaning step reduces the presence of contaminants including dirt, plastic, woods etc. on the material before separation. Such a step improves the quality of the outputs obtained from the separation steps and improves the purity of the outputs. Moreover, the arrangement reduces the amount of downstream treatment the separated outputs require before being suitable for re-use, and thus improves the value of the output.

In exemplary embodiments, the cleaning step includes subjecting the shredded, ground or fragmented waste material to a suction of air, such that contaminants material can be suctioned away by the air.

In exemplary embodiments, the cleaning step is after the screening step.

In exemplary embodiments, the first output is transported directly from the first separation stage to the second separation stage via the second flow path.

Advantageously, there are no intermediate steps between the first and second separations. As such, the overall process is simple and requires minimal equipment outside of the rotating drums to arrive at the desired product.

In exemplary embodiments, the separation characteristic of at least one of the separation steps is variable based on a predetermined output or based on a characteristic of the flow of waste material.

Advantageously, the method can be utilised to extract a wide variety of outputs, or to separate a wide variety of inputs, depending on the demand for a certain type of product, or the input into the process. Such can improve flexibility of the method, thus preventing any equipment becoming obsolete if demand for a certain material changes, or if a different input is to be separated.

In exemplary embodiments, the predetermined output is based on at least one of: a desired purity of ferrous material in the second output, a desired density of ferrous material in the second output, and a desired mass of ferrous material in the second output.

In exemplary embodiments, the predetermined output is based on at least one of: a desired purity of ferrous material in the fifth output, a desired density of ferrous material in the fifth output, and a desired mass of ferrous material in the fifth output.

Advantageously, the type of ferrous material (i.e. the chemical properties of the material) extracted from the process can be selected based on the separation characteristic determined by an operator, which will improve the value of the output of the separation, as well as preventing the need for further processing if the demand changes.

According to a second aspect of the invention, there is provided a system for processing a flow of waste material, the system comprising: a first separation apparatus comprising a first flow path configured to transport waste material, and a first rotating drum arranged adjacent the first flow path, the first rotating drum configured to magnetically collect a first output of material from said flow, the first output comprising ferrous material; a second separation apparatus comprising a second flow path configured to transport the first output, and a second rotating drum arranged adjacent the second flow path, the second rotating drum configured to magnetically collect a second output of material from the first output, the second output comprising ferrous material; wherein each separation apparatus is configured with a separation characteristic different from the other such that the ferrous content of the first output is different from the ferrous content of the second output.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic of a system according to an embodiment of the present teachings; Figure 2 is a schematic of a first separation apparatus according to an embodiment of the present teachings; Figure 3 is a schematic of a third separation apparatus according to an embodiment of the present teachings; Figure 4 is a flow diagram of a method according to an embodiment of the present teachings.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to Figure 1, a system for processing a flow of waste material is indicated generally at 1.

The system 1 includes a first separation apparatus 2 and a second separation apparatus 3. The system 1 also includes a third separation apparatus 4. However, it should be appreciated that the third separation apparatus 4 may not be present in some embodiments.

The movement of material through the system 1 is represented in Figure 1 by a series of arrows, indicating the general direction of travel of the material relative to the system 1 itself. It should be understood that the direction of travel of the material is relative to the specific orientation of the system 1, and so could be in a different direction if the system 1 were to be reoriented.

A flow of waste material for being processed in the system is defined generally at 5. The flow of waste material 5 can originate from waste vehicles, white goods, garden furniture, or any suitable source. The waste material 5 is preferably shredded, ground or otherwise fragmented prior to being processed in the system 1. In some embodiments, the process of shredding, grinding and fragmenting the waste material 5 can be part of a pre-treatment process, e.g. at or adjacent the location of the system 1.

The flow of waste material 5 includes metals. The flow of waste material includes both ferrous materials and non-ferrous materials in exemplary embodiments.

The term "ferrous material" as used herein refers to materials that are magnetic, meaning materials that is attracted to magnets.

Ferrous materials are traditionally metals that contain iron as their main component. It should be appreciated that the term "ferrous material" as used herein may also refer to metals that do not contain iron, but exhibit magnetic properties.

Ferrous material can include, by way of example, steel, iron, cast iron and wrought iron in exemplary embodiments.

The term "non-ferrous material" as used herein refers to materials that are non-magnetic, meaning materials that are not attracted to magnets.

In the present teachings, it is expected that the flow of waste material 5 includes various types of non-ferrous materials, including both non-ferrous metals and non-metals. Nonferrous metals can include, by way of example, aluminium, copper, brass, bronze, lead, zinc, nickel, titanium, magnesium. Non-metals present in the flow of waste material 5 can include, by way of example, plastic, foam, wood, glass, and rubber.

The composition of the flow of waste material 5 will be dependent on the source of the waste. The system 1 and method set forth are intended to be generally suitable for processing any composition of ferrous and non-ferrous waste.

The first separation apparatus 2 defines a first flow path 6. The flow path 6 is configured to transport the flow of waste material 5. In exemplary embodiments, the flow of waste material 5 is introduced onto the first flow path 6 for processing in the first separation apparatus 2, for example, the flow of material 5 may be manually loaded onto the flow path 6. Exemplary embodiments of flow paths will be discussed in more detail below.

It should be understood that the term "flow path" and the term "conveyor" as used herein is intended to mean a mechanical flow path, having a surface which is mechanically moveable so as to translate material thereon from one location to another (e.g. a conveyor belt or the like).

The first separation apparatus 2 includes a first rotating drum 7. As can be seen, the first rotating drum 7 is arranged adjacent the first flow path 6. The first rotating drum 7 is configured to magnetically collect a first output of material 8 from the flow of waste material 5 along the first flow path 6. The system 1 is configured so that the first output 8 includes ferrous material.

It should be understood that by "adjacent" it is meant that the first rotating drum 7 is suitably close to the first flow path 6 so as to magnetically collect the first output 8. In some embodiments, the first rotating drum 7 is positioned directly above the first flow path 6. In some embodiments, the first rotating drum 7 is offset horizontally from a terminal end of the first flow path 6.

Alternatively, the first rotating drum 7 is positioned directly after the first flow path 6 terminates. In such an embodiment, the drum 7 is not spaced apart from the flow path 8, but rather is directly adjacent the terminal end of the flow path 8 such that material flows from the flow path directly to the drum (i.e. without a "gap" between the flow path and the drum).

Alternatively, and in the illustrated embodiment, the first rotating drum 7 is arranged spaced apart from the first flow path 6 in both a vertical and a horizontal direction.

In the illustrated embodiments, the first rotating drum 7 defines a generally circular cross section.

The first rotating drum 7 is configured to generate a magnetic field.

In Figure 1, the first flow path 6 and the first rotating drum 7 are arranged such that the first output 8 is liberated from the flow of waste materials 5. The first output 8 includes ferrous material, and so the magnetic field generated by the first rotating drum 7 attracts the ferrous material, thus causing the first output 8 to move toward the first rotating drum 7.

In some embodiments, the first rotating drum 7 is configured such that the first output 8 adheres to or moves relative to a surface of the first rotating drum 7. The drum 7 is rotatable, and can rotate while the first output 8 is adhered or attracted thereto. In this way, the first rotating drum 7 serves to transport the first output 8 away from and downstream of the first flow path 6. A more detailed configuration of the first rotating drum 7 will be discussed in more detail below.

In some embodiments, the first output 8 does not adhere directly to a surface of the first rotating drum 7. Instead, the magnetic field and the rotation of the drum 7 can cause the first output 8 to be suspended and flow around the surface of the drum 7 without being adhered thereto.

As shown in Figure 1, the first separation apparatus 2 can generate an additional output, referred to as a third output 9. In this way, the first separation apparatus 2 can be seen as separating the flow of waste material 5 into the first output 8 and the third output 9.

The third output 9 is defined as any material remaining from the initial flow of waste material 5 after the first output 8 is magnetically collected. Put another way, while the first output 8 is defined by materials from the flow of waste material 5 magnetically collected by the first rotating drum 7, the third output 9 is defined by materials from the flow of waste material 5 that are not magnetically collected by the first rotating drum 7.

In exemplary embodiments, the first separation apparatus 2 is configured such that the first flow path 6 and the first rotating drum 7 are arranged so as to be in an elevated position relative to the ground. For example, the first flow path 6 and the first rotating drum 7 can be supported by a series of support structures that maintain the apparatus 2 in a fixed position above the ground. It should be appreciated that any suitable means to arrange the apparatus 2 in an elevated position could be utilised.

Elevating the apparatus 2 in this way facilitates the third output 9 to fall under gravity toward the ground. The third output 9 may be collected in a receptacle or other vessel or container (e.g. a bin) positioned beneath the first rotating drum 7 and disposed of, sold, or sent for further processing.

It should be understood that the separation apparatus 2 may not be elevated in an alternative embodiment.

As can be seen in Figure 1, the first flow path 6 terminates so as to define an end of the flow path 6 proximal the first rotating drum 7. The termination of the first flow path 6 causes the flow of waste material 5 to be projected from the end of the first flow path 6 into the magnetic field of the first rotating drum 1.

In response to being projected into the magnetic field of the first rotating drum 7, the first output 8 is attracted to the magnetic field and moves toward the drum 7, while the third output 9 is not attracted to the magnetic field and so falls under gravity. In the illustrated embodiment, there is a space between the end of the flow path 6 and the drum 7, so as to facilitate the third output 9 falling when projected into the space (i.e. rather than being collected by the magnetic field of the drum 7 as with the first output 8).

In this way, the first separation apparatus 2 can be seen as utilising both magnetism and gravity in separating the flow of waste material 5 into the first output 8 and the third output 9.

The first rotating drum 7 is configured to move the first outputs out of the first separation apparatus 2. In exemplary embodiments, the first and second separation apparatus 2, 3 are arranged relative to each other such that the first output 8 moves from the first rotating drum 7 to the second separation apparatus 3.

The second separation apparatus 3 shares many similarities with the first separation apparatus 2. For this reason, only the differences between the apparatus will be discussed in detail.

The second separation apparatus 3 defines a second flow path 10. The second flow path 10 is configured to transport the material from the first output 8.

In Figure 1, the first rotating drum 7 and the second flow path 10 are arranged relative to each other such that the first output 8 falls from the drum 7 to the second flow path 10.

In this way, the first output 8 can be seen as being transported directly from the first separation apparatus 2 to the second separation apparatus 3, i.e. without any intermediate processing therebetween.

Put another way, the first separation apparatus 2 and the second separation apparatus 3 can be seen as being arranged in series with one another.

The use of two rotating drums 7, 11 arranged as illustrated has been found to provide a better overall extraction of ferrous material from the flow of waste materials 5.

It should be appreciated that some losses may occur as the first output 8 is transported between the first and second separation apparatus 2, 3, e.g. due to some material falling. However, in general, the input into the second separation apparatus 3 is substantially the same as the output of the first separation apparatus 2.

The second separation apparatus 3 includes a second rotating drum 11. The drum 11 is arranged adjacent the second flow path 10. The drum 11 is configured to magnetically collect a second output of material 12 from the first output 8 on the second flow path 10.

The second output 12 includes ferrous material.

The second rotating drum 11 can be configured to collect the second output 12 in substantially the same way as the first rotating drum 8 collects the first output 8.

The second separation apparatus 3 can generate an additional output, referred to herein as the fourth output 13. As such, the second separation apparatus 3 can be seen as separating the first output 8 from the first separation apparatus 2 into the second output 12 and the fourth output 13.

The fourth output 13 is defined as material remaining from the first output 8 after the second output 12 is magnetically collected by the second rotating drum 11. Put another way, while the second output 12 can be defined by materials from the first output 8 magnetically collected by the second rotating drum 11, the fourth output 13 is defined by materials from the first output 8 that are not magnetically collected by the second rotating drum 11.

In exemplary embodiments, the second separation apparatus 3 is configured such that the second flow path 10 and second rotating drum 11 are elevated relative to the ground. The second separation apparatus 3 may not be elevated in alternative embodiments.

The second flow path 10 can be arranged relative to the second rotating drum 11 such that the first output 8 can be projected from an end of the flow path 10. The second output 12 is attracted by a magnetic field generated by the second rotating drum 11 and can move toward the drum. The fourth output 13 is not attracted to the magnetic field or is not attracted enough to overcome the downward force of gravity and so falls under gravity.

The second rotating drum 11 is configured to move the second output 12 out of the second separation apparatus 3. In the illustrated embodiment, the second output 12 is moved from the drum 11 to a product flow path 14. In some embodiments, the second output 12 is moved to a collection area via the product flow path 14, e.g. into a receptacle or a bin drums for sale of the output 12, or is moved for additional processing downstream. In alternative embodiments, the product flow path 14 is not present and the second output 12 moves directly from the rotating drum 11 to a collection receptacle.

In the illustrated embodiment, the fourth output 13 moves from the second separation apparatus 3 to the third separation apparatus 4. As can be seen, the third separation apparatus 4 is arranged at a lower elevation relative to the second separation apparatus 3. In this way, the fourth output 13 can fall under gravity from the flow path 10 of the second separation apparatus 3 to the third separation apparatus 4 for further processing.

In alternative embodiments, the third separation apparatus 4 is not at a lower elevation relative to the second separation apparatus. For example, in such an embodiment the fourth output 13 is transported via an additional flow path from the second separation apparatus 3 to the third separation apparatus 4.

It should be understood that the first, second and third separation apparatus 2, 3, 4 can be arranged at any elevation relative to each other and the ground.

It should be appreciated that the third separation apparatus 4 may not be present in alternative embodiments. Instead, in some embodiments, the fourth output 13 can be collected in a receptacle, vessel or other form of container for disposal, sale, or further processing.

Although not discussed in detail, it should be appreciated that the arrangement and configuration of the second separation apparatus 3 can be the same as that described in relation to the first separation apparatus 2. Any combination of the features described in relation to the first separation apparatus 2 can be applied to the second separation apparatus 3. Similarly, the third separation apparatus 4 can include any combination of features described in relation to the first and/or second apparatus 2, 3.

The first and second separation apparatus 2, 3 are each configured with a separation characteristic. The separation characteristic of each apparatus 2, 3 can be seen as defining a desired separation obtainable when the apparatus is in use.

The separation characteristic of each apparatus 2, 3 can be a function of a number of parameters associated with the apparatus.

The separation characteristic of the first separation apparatus 2 is different from the separation characteristic of the second separation apparatus 3, such that the ferrous content of the first output 8 is different from the ferrous content of the second output 12.

The term "ferrous content" as used herein can refer to an amount of ferrous in a particular flow of material. In this way, the ferrous content of a material can be seen as a concentration or fraction by weight or by volume of ferrous material present in an output or a flow of materials. "Different ferrous content" can also refer herein to ferrous materials having different properties, e.g. an output containing less dense or less heavy ferrous and an output containing more dense or more heavy ferrous can be referred to as having differing ferrous contents.

It should be understood that the outputs of each separation stage include multiple component parts. The separation characteristic of each apparatus is configured such that the component parts of each output collectively possess chemical and physical properties that are different to the component parts of another output. Put another way, if the component parts of the first output 8 were melted down and turned into an alloy, such an alloy would be chemically and physically different than a respective alloy formed from the component parts of the second output 12. As such varying "ferrous content" may also refer to the variation in chemical or physical properties of a respective output compared to another output.

In exemplary embodiments, all of the outputs of the process exhibit different chemical properties from each other.

Configuring the apparatus 2, 3 as set forth has been found to be useful for effectively separating potentially valuable ferrous materials from materials with less value that may be present in the flow of waste material 5.

In exemplary embodiments, the first and second separation apparatus 2, 3 can be configured so that the first rotating drum 7 provides an initial screening of the waste material, while the second drum 11 collects ferrous from the initially screened output, i.e. the first output 8.

The arrangement of the two apparatus 2, 3 is particularly beneficial for processing clumped material, i.e. ferrous material clumped with non-ferrous material. Such clumps occur when different types of material agglomerate together. Extracting the ferrous material from such clumps can be complex to achieve in a single processing step (i.e. using a single drum 7), since the ferrous material can be weighed down by dense, non-ferrous materials.

In some embodiments, the flow of waste material 5 is provided in many layers, i.e. the material flows along the first flow path 6 in a heap, with various materials piled on one another. As will be appreciated, extracting an outlet with a high concentration of ferrous material (i.e. high purity) can be extremely difficult in this scenario.

The provision of the second separation apparatus 3 and the different separation characteristics of the two apparatus 2, 3 has been found to vastly improve the purity of the resulting outputs (i.e. reducing the presence of undesirable impurities such as copper), as well as improving the amount of ferrous material extracted. As such, the value of the final product can be improved, and the material can be effectively re-used in new products requiring ferrous materials.

The first and second separation apparatus 2, 3 will now be discussed in more detail with reference to Figure 2.

Figure 2 is a schematic of the first separation apparatus 2 and the second flow path 10. It should be appreciated that the second separation apparatus 3 can be arranged in substantially the same way as the first. As such, Figure 2 can also be indicative of the arrangement of the second separation apparatus 3 and the product flow path 14 in exemplary embodiments.

Figure 2 indicates a cross-sectional view of the first rotating drum 7. In the illustrated embodiment, the first rotating drum 7 is in the form of a first drum magnet. The first drum magnet includes a rotatable shell 15 and a stationary magnet 16 positioned within the rotatable shell 15.

Put another way, the rotatable shell 15 defines a housing for receiving the stationary magnet therein 16.

In use, the rotatable shell 15 rotates about a longitudinal axis of the first rotating drum 7.

The stationary magnet 16 is stationary with respect to the shell 15, such that the shell 15 rotates relative to the magnet 16.

In exemplary embodiments, the stationary magnet 16 includes an electromagnet. It should be appreciated that other forms of magnet may be suitable.

Although the figures indicate the magnet 16 as a substantially ovular shape, it should be appreciated that the magnet 16 can be any suitable shape.

The system 1 can be configured such that the separation characteristic of the first separation apparatus 2 is a function of at least the strength of the stationary magnet 16.

The strength of a magnet can be defined by the strength of the magnetic field generated by the magnet, the magnetic flux density of the magnet, or the ability of the magnet to attract materials. In this way, a magnet with a higher strength can collect more ferrous material than a magnet with a lower strength since the higher strength magnet is more likely to liberate the ferrous material from any clumps.

The strength of a magnet is typically measured in Tesla or Gauss, where a higher Tesla/Gauss indicates a stronger magnet (NB: 1 tesla = 10000 gauss). As used herein, the term "Gauss" may be used as an indication as to the strength of the magnet.

As indicated above, the second rotating drum 11 may be in the same form as the first rotating drum 7. Specifically, the first and the second rotating drums are in the form of first and second drum magnets, each having a rotatable shell and a stationary magnet.

In this way, the separation characteristic of the second separation apparatus 2 is a function of at least the strength of the respective stationary magnet of the second drum magnet.

Utilising the strength of each magnet to influence the separation has been found to be an effective way of selectively separating the flow of waste material into the first and second outputs. More specifically, the strength of the magnets can influence the type of materials collected by each rotating drum 7, 11, since the stronger magnet can collect a large amount of ferrous material compared with the weaker magnet.

In exemplary embodiments, the system 1 is configured such that the stationary magnet 16 of the first rotating drum 7 has a greater strength than the stationary magnet of the second rotating drum 11.

In a magnetic separation, some ferrous material will avoid separation/collection by the drum if the magnet is not strong enough, e.g. the magnetic field of the magnet may not generate enough upward force to overcome the downward force of the weight of material, or to liberate the material from a clump or heap of non-ferrous or less-ferrous materials.

As such, configuring the magnet 16 of the first rotating drum 7 to be the stronger of the two advantageously serves to extract as much ferrous material as possible from the flow of waste material 5 in the first separation apparatus 2 to transport to the second separation apparatus 3 for further processing, or fine tuning. It has been found to be advantageous for the magnet of the second rotating drum 11 to have a lower comparative strength, in order to be more selective about the type of ferrous material that it collects.

It will be understood that the strength of the magnets in each rotating drum 7, 11 can be selected in any way relative to one another by an operator (or by a control system in some embodiments) based on the operational requirements of the system 1. In this way, the magnet in at least one of the drums 7, 11 may be considered to be variable.

In the exemplary embodiment noted above, the magnet 16 of the first rotating drum 7 has a greater Gauss than the magnet of the second rotating drum 11 at a respective drum surface. It should be understood that the Gauss of a magnet can vary depending on the location relative to the magnet the measurement is taken.

Typically, the magnet 16 of the first rotating drum 7 is configured to generate a Gauss in the range 400 to 3000 G at a surface of the first drum 7, preferably 8000 to 3000 G at a surface of the first drum 7, preferably in the range 1500 to 2500 G, more preferably in the range 1500 to 2000 G, more preferably in the range 1800 to 2000 G. In exemplary embodiments, the magnet 16 of the first rotating drum 7 is configured to generate a Gauss of 1900 G at a surface of the first drum 7.

Operating the magnet 16 of the first drum 7 at a Gauss of 1900 G has been found to improve the extraction of ferrous material from the flow 5 by the first separation apparatus 2, thus minimising loss of ferrous during processing by the first apparatus 2 and maximising the yield the system 1 can obtain in use.

In some embodiments, the magnet 16 of the first rotating drum 7 is a permanent magnet with a fixed Gauss.

Typically, the magnet of the second rotating drum 11 is configured to generate a Gauss in the range of 100 to 2000 G at a surface of the second drum 11, preferably in the range to 1500 G, more preferably in the range 300 to 1300 G (e.g. 325 G, 1220 G).

In further exemplary embodiments, the magnet of the second rotating drum 11 is configured to generate a Gauss in the range of 500 G to 1200 G at a surface of the second drum 11, more preferably in the range of 700 G to 1000 G, more preferably in the range of 850 G to 950 G. In exemplary embodiments, the magnet of the second rotating drum 11 is configured to generate a Gauss of 910 G at a surface of the second drum. Operating the magnet of the second drum 11 at a Gauss of 910 G has been found to be particularly preferable in improving the separation obtained by the second separation apparatus 3, and thus the overall separation of the system 1 is improved.

In some embodiments, the magnet of the second rotating drum 11 is a variable magnet with a variable Gauss.

In an exemplary embodiment, the magnet 16 of the first rotating drum 7 is operated with a Gauss in the range of 400 G to 3000 G and the magnet of the second rotating drum is operated with a Gauss in the range of 100 to 2000 G. In another embodiments, the magnet of the first rotating drum 7 is operated with a Gauss of 1900 G and the magnet of the second rotating drum 11 is operated with a Gauss of 910 G. It should be understood that the first and second rotating drums may be operated in combination to obtain any of the a bovementioned Gauss values.

In exemplary embodiments, the system 1 is configured such that the separation characteristic of the first separation apparatus 2 is a function of at least the relationship between the speed at which the drum 7 (i.e. the shell 15) rotates about a longitudinal axis of the drum 7 and a movement speed of the first flow path 6. The system 1 can also be configured such that the separation characteristic of the second separation apparatus 3 is a function of at least the relationship between the speed at which the drum 11 (i.e. the respective rotatable shell) rotates about a longitudinal axis of the drum 11 and a movement speed of the second flow path 10.

The speed (sometimes referred to as rotational speed, RPM (revolutions per minute), or angular speed) of a respective shell of a drum magnet has been found to influence the amount of ferrous material exposed to the magnetic field generated by the magnet.

Specifically, the speed of a drum relative to the movement speed of a respective flow path can advantageously be adapted to influence the exposure of ferrous material to the magnetic field of the respective magnet. The speed of a drum can be advantageously adapted to influence the separation of materials. In particular, the speed of the drum relative to the speed of the flow path has an impact on the surface area of the drum that is available to collect ferrous material from a respective flow path (i.e. if the speed of the drum relative to the flow path increases then there is more available surface area presented to the flow path).

In some applications, altering the speed of a drum by operating the drum at a faster speed and/or altering the flow path speed by reducing the flow path speed increases the available surface area of the drum, and so increases the likelihood that ferrous material will be collected by the drum, thus improving the purity of the final products.

The speed of each drum 7, 11 can be controlled by an operator (or a control system in some embodiments) based on operational requirements.

In exemplary embodiments, the first drum 7 is configured to rotate at greater speed relative to the speed of the first flow path 6 compared with the speed of the second drum 11 relative to the speed of the second flow path 10.

In this way, the first drum 7 has a greater surface area available to the material 5 on the flow path 8, thereby increasing the likelihood that ferrous material will be collected by the first drum 7. In such an embodiment, the first drum 7 can be seen as providing a "coarse" separation, i.e. extracting as much ferrous material as possible, while the second drum 11 can be utilised to fine tune the output 8 of the first drum 7.

Combining the high strength of the magnet of the first drum 7 with the greater relative speed of the drum 7 (i.e. relative to the flow path 6) has been found to increase the amount of ferrous material in the flow of waste materials 5 collected by the drum 7, and reduce the ferrous content of the third output 9, i.e. since the majority of the ferrous is collected by the first rotating drum 7. The second separation apparatus can then provide a fine-tuned separation of the ferrous collected by the first drum 7. The second separation apparatus is provided with a weaker magnet, and lower relative speed of the drum (i.e. relative to the flow path) so as to provide a more selective separation of the ferrous material collected in by the first drum 7.

Typically, the first drum 7 is configured to rotate at a speed in the range of 1 to 20 RPM (e.g. 1 RPM, 2 RPM, 3 RPM, 4 RPM, 5 RPM 6 RPM, 7 RPM etc.), preferably in the range of 5 to 15 RPM, preferably in the range of 8 to 12 RPM, preferably in the range of 9 to 11 RPM.

In exemplary embodiments, the first drum is configured to rotate at 10 RPM.

In exemplary embodiments, the first flow path 6 is configured to operate at a speed in the range of 0.1 and 1 m s-1, preferably in the range of 0.1 and 0.5 m s-1, more preferably in the range of 0.2 and 0.4 m In exemplary embodiments, the first flow path 6 is configured to operate at a speed of 0.3 m s-1.

Operating the first drum 7 at 10 RPM and the first flow path 6 at 0.3 m s -1 has been advantageously found to increase the amount of ferrous collected by the first drum 7, thereby reducing loss of valuable material.

Typically, the second drum 11 is configured to rotate at a speed in the range of 10 to 30 RPM (e.g. 10 RPM, 11 RPM, 12 RPM etc.), preferably in the range of 10 to 25 RPM (e.g. 11.5 RPM, 23 RPM), more preferably in the range of 15 to 20 RPM.

In exemplary embodiments, the second drum 11 is configured to rotate at 19 RPM.

In exemplary embodiments, the second flow path 10 is configured to operate at a speed in the range of 0.5 and 5 m s-1, preferably in the range of 1 and 3 m s-1, (e.g. 1 m 1.18 m s-1, 1.5 m s1,2 m s-1, 2.35 m s, 2.5 m 5-1, 3 m s-1), more preferably in the range of 1 and 2 m s-1, more preferably in the range of 1.4 and 1.7 m s-1.

In exemplary embodiments, the second flow path 10 is configured to operate at a speed of 1.65 m s-1.

Operating the second drum 11 at a speed of 19 RPM and the second flow path 10 at 1.65 m s-1 has been found to improve the selectivity of the second drum and increase the purity of the final product.

The flow paths 6, 10 are in the form of any moving surface along which material is transported.

In some embodiments, the flow paths 6, 10 are provided as first and second conveyors having respective movement speeds. One or both of the conveyors may be in the form of a belt conveyor in some embodiments. In exemplary embodiments, the second conveyor is a belt conveyor.

Although the flow paths 6, 10 are discussed as conveyors in relation to the illustrated embodiment, it should be understood that any form of moving surface could be utilised to transport the material between the apparatus. As such, it should be understood that the term "conveyor" used herein can be interchanged with any moving surface along which material is transportable. Moreover, it should be understood that the speed of a respective flow path relates to the movement speed of a surface on which material is transported (e.g. the belt speed).

The separation characteristic of the first and/or second separation apparatus 2, 3 is a function of a direction of rotation of the respective rotatable shell about a respective longitudinal axis of each drum 7, 11 in some embodiments.

The direction of rotation of the shells can be used to control the influence of gravity on the separation of each step, and thus the influence density or mass of material has on the overall separation.

In some embodiments, an operator can control the direction of rotation, which can allow the operator to manipulate the influence magnetism and gravity have in each separation in the respective apparatus 2, 3.

As can be seen in Figure 2, the shell 15 of the first rotating drum 7 rotates in a direction that facilitates the flow of the collected first output 8 over the first drum magnet 7. Such a configuration may be referred to as the drum being "overfed". The direction of rotation of the shell 15 is indicated by the arrows included on the shell 15 in the figure.

As indicated by the dashed arrows in Figure 2, the first output 8 is projected from an end of the first flow path 6 (e.g. into a space between the flow path 6 and the drum 7), enters the magnetic field of the magnet 16 and is attracted to the rotating drum 7. The material of the first output 8 is thus lifted by the magnetic field and moves in the direction of rotation of the shell 15 over the drum 7. The first output 8 then falls from the drum 7 to the second flow path 10.

In Figure 2, the external shell 15 of the first drum magnet rotates in a clockwise direction. It should be appreciated that in some embodiments flow of material moves in the opposite direction (i.e. from right to left when viewing the page). In this case, the external shell 15 may rotate in an anticlockwise direction. It should be understood that the external shell rotates in a direction to facilitate movement of material over the shell, rather than under the shell (i.e. the rotation can be in the clockwise direction if flow moves in the opposite direction to that shown in the figures).

In exemplary embodiments, the shell of the second drum magnet rotates in the same direction as the shell 15 of the first drum magnet.

In such an embodiment the first and second outputs 8, 12 can be lifted over the respective drums, such that the magnetism of the material is the key component that the separation is based on.

Where the first separation apparatus 2 is configured so as to provide an initial screening of the material, such a rotational direction maximises the amount of ferrous carried over to the second separation apparatus 3, so as to minimise loss of potentially valuable ferrous (i.e. more dense material is less likely to fall away under gravity once engaged with the drum 7, since the material flows over the drum 7 and is therefore supported by the drum surface, e.g. the shell).

In such an embodiment, the magnetic properties of the materials have a greater influence on the separation than the density or mass of the materials (i.e. the influence of gravity). In this way, the separation can be seen to be primarily based on magnetic properties of the materials.

In some embodiments, either shell may be configured to rotate in an opposite direction, such that material collected by the rotating drum moves under the rotating drum. Such a configuration may be referred to as the drum being "underfed". In this way, the influence of gravity on the separation is greater, and so only materials that are sufficiently magnetic will be prevented from falling from the drum. This effect will be discussed in more detail further below in relation to the third separation apparatus 4.

The separation characteristic of the first and/or second separation apparatus 2, 3 can be a function of a relative position of the magnet within the shell of the drum 7, 11 in some embodiments.

Utilising the position of the magnet within the shell has been found to increase the flexibility of the system 1 to base the separations on magnetism and/or mass. This can improve the value of the products extracted by the system 1 since the composition (i.e. the chemical properties) of the products can be adjusted based on the desired separation.

As shown in Figure 2, the magnet 16 is positioned within the shell 15 so as to be adjacent the first flow path 6. Put another way, the magnet 16 is only located on one side of the shell, i.e. the side of the shell adjacent to the first flow path 6. In this way, a stronger magnetic field is generated about the side of the shell 15 adjacent the first flow path 6 when compared with the magnetic field at the opposite side of the shell 15 (i.e. the side adjacent the second flow path 10).

Positioning the magnet in such a way assists in the collection of significant amounts of ferrous material, thereby preventing significant loss of valuable ferrous material that may be less likely to be collected by the drum 7 (e.g. because it is clumped with other, nonferrous material, or because it is heavier or more dense). Such an arrangement prevents significant loss of valuable material and improves the overall efficiency of the separation.

Moreover, positioning the magnet 16 as set forth in combination with the direction of rotation of the shell 15 indicated in Figure 2 permits the first output 8 to be collected by the drum 7 (i.e. via the magnetic field generated by magnet 16), move over the first rotating drum 7, and then fall from the drum to the second flow path 10. The first output 8 falls from the drum 7 because the side adjacent the second flow path 10 is less magnetised (i.e. has a weaker magnetic field) and so the material in the first output 8 is no longer attracted by the magnet 16 and so falls under gravity to the second flow path 10.

In exemplary embodiments, the magnet of the second rotating drum 11 is arranged in the same way as the magnet 7 in the first rotating drum 7. The arrangement assists in the collection of the ferrous material, while also reducing losses of ferrous material once collected by the second rotating drum 11.

As shown in Figures 1 and 2, the first and second rotating drums 7, 11 are arranged so as to be spaced apart from the respective first and second flow paths 6, 10 so as to define a respective first and second clearance between the drum 7, 11 and the flow path 6, 10.

The separation characteristic of the first and/or second rotating separation apparatus 2, 3 can be a function of the respective clearance in some embodiments.

The clearance can be seen as a distance between a terminal end of the flow path 6, 10 and the respective drum 7, 11 surface. The clearance can be measured in a horizontal direction (x-direction), a vertical direction (y-direction) or a transverse direction (z-direction). In some embodiments, the clearance is the distance between the terminal end of the flow path 6, 10 and the closest surface of the drum magnet 7, 11.

Utilising the clearance between the drums 7, 11 and the flow paths 6, 10 has been found to be an effective means of influencing the separation of the waste material 5. In particular, the clearance between the drums 7, 11 and the flow paths 6, 10 can be selected to assist with separation based on not only magnetic properties of the waste material (i.e. ferrous vs non-ferrous) but also separating based on the mass of the material. In this way, the separation may be controlled such that only lighter ferrous materials are collected by the drum (meaning that heavier materials are not collected).

In some embodiments, a large proportion of the flow of waste material is the same type of material (e.g. steel), thus large proportions of the material 5 have the same density. In this embodiment, the influence of gravity can separate the material based on its mass.

For example, some of the material may be in the form of sheet metal, having a higher volume and thus a lower mass. Some of the material may be in the form of lumps of metal (e.g. a solid block), that has a lower volume and thus a higher mass. In this way, increasing the influence of gravity on the separation may increase the likelihood that the lighter metal (e.g. sheet metal) is collected, and the heavier metal (e.g. metal lumps) falls under gravity.

Increasing the influence gravity has on the separation (e.g. by increasing said clearance) has been found to promote separation of ferrous materials based on their respective magnetism. Put another way, heavier (e.g. denser) ferrous material that is strongly attracted to the magnetic field of the drums is more likely to be collected than lighter (e.g. less-dense) ferrous material that is less attracted to said magnetic field. In this way, the chemical and physical properties of the final product can be altered based on the demand for certain products.

Utilising a clearance between a flow path 6, 10 and a respective drum 7, 11 also facilitates the projection of the material from a terminal end of the flow path 6, 10. In this way, nonferrous material will likely fall away from the drum 7, 11, while ferrous material will move toward the drum 7, 11 for collection.

The use of a clearance can cause some ferrous material to fall away from the drum 7, 11 if, for example, it is too heavy for the force of attraction to the magnetic field to overcome the force of gravity.

In this way, incorporating a clearance in the second separation apparatus 3 has been found to be particularly advantageous when configuring the second separation apparatus 3 for "fine tuning". In exemplary embodiments, the second apparatus 3 can fine tune the output 8 of the first apparatus 2 into a separation of lighter (e.g. less-dense), purer ferrous being collected by the second drum 11, with heavier (e.g. more-dense), less-pure ferrous not being collected.

The clearance in the second separation apparatus 3 is particularly advantageous in combination with the magnet of the second drum 11 being less strong than the first magnet 16. In this way, the mass of the components in the material is more influential in the separation in the second separation apparatus 3 compared with the first 2.

Typically, the clearance between a surface of the first flow path 6 and the closest surface of the drum 7 is in the range of 100 and 500 mm, preferably in the range of 200 and 400 mm, more preferably in the range of 300 and 400 mm.

In exemplary embodiments, the clearance between a surface of the first flow path 6 and the closest surface of the drum 7 is 370 mm.

Typically, the clearance between a surface of the second flow path 10 and the closest surface of the second drum 11 is in the range of 100 and 500 mm, preferably in the range of 200 and 400 mm, more preferably in the range of 300 and 400 mm.

The clearance between the second flow path 10 and second drum 11 is 370 mm in some embodiments.

In exemplary embodiments, the clearance of either apparatus 2, 3 can be adjusted to alter the impact gravity has on the separation.

The separation characteristic of the fist and/or second separation apparatus 2, 3 is a function of the movement speed of a respective conveyor (i.e. a flow path) in exemplary embodiments.

In some embodiments, the movement speed of a respective conveyor can have an independent influence on the separation obtained in each apparatus.

In exemplary embodiments, the first flow path 6 and second flow path 10 are configured such that the second flow path 10 has a surface movement speed that is greater than a surface movement speed of the first flow path 6.

Put another way, the second conveyor is configured to operate at a greater speed than the first conveyor.

The greater speed of the second conveyor serves to provide a thinner layer of material on the second conveyor, since the second conveyor will be moving at a greater speed when the first output is introduced to the second conveyor from the first drum 7. In this way, material of the first output that is on the second conveyor is less likely to pile up, and instead will be dispersed more evenly across the surface of the second conveyor (i.e. compared to the arrangement of material on the first conveyor, which is generally less distributed).

A thinner layer of material on the second conveyor can improve the effectiveness of the second separation apparatus 3, since the material is introduced to the second drum 11 in a more singular form (i.e. more evenly distributed about the conveyor), and so it is less likely that material will be erroneously collected/not collected by the second rotating drum 11.

The relative speed of the first rotating drum 7 can also assist in promoting the introduction of material to the second conveyor in a more dispersed form, i.e. the speed of the first rotating drum 7 influences the speed at which the material is introduced to the second conveyor, and therefore influences the distribution of the material on the conveyor.

The arrangement set forth is particularly advantageous when the stationary magnet 16 of the first rotating drum 7 has a greater strength than the stationary magnet of the second rotating drum 11.

In this way, the first rotating 7 drum can collect a large amount of material, including as much ferrous as possible, for fine tuning in the second apparatus 3. Having the second conveyor at a greater speed allows the material to be more evenly distributed on the conveyor when exposed to the second drum 11 (e.g. essentially one piece of material at a time approaches the drum 11), resulting in a more effective extraction of ferrous material, and thus a purer product.

In some embodiments, one or both of the conveyors/flow paths is configured to vibrate. Vibrating of the flow paths causes the material thereon to be more evenly dispersed.

In some embodiments, the first conveyor is a vibratory conveyor.

It is particularly advantageous for at least the first conveyor to vibrate in use, so as to reduce the pile-up of waste on the first conveyor. In this way, the waste can be more effectively distributed across the conveyor to reduce the presence of clumps of material and improve the effectiveness of the first separation stage.

In some embodiments, the first rotating drum 7 and the second flow path 10 are arranged and configured relative to each other such that material falls from the drum 7 to the flow path 10 in such a way so as to be spread across the full width of the flow path 10.

For example, in some embodiments, the drum 7 is arranged relative to the flow path 10 such that material "bounces" onto the second flow path 10 and spreads across the width of the flow path 10. Such an arrangement assists in promoting the distribution of the material as it moves across the second flow path 10 to the second rotating drum 11.

As discussed above, the various parameters influencing separation characteristics of the apparatus 2, 3 can be adjusted as required by an operator or a control system. The combination of the two separation apparatus 2, 3 in series with the adjustable separation characteristics has been found to result in a system 1 that can manage various types of waste materials and can obtain high purity materials therefrom. Such a system 1 is highly flexible to achieve a desired operational outcome.

An exemplary configuration of the first separation apparatus 2 and the second separation apparatus 3 will now be discussed.

In exemplary embodiments, the separation characteristic of the first separation apparatus 2 is configured such that the third output 9 contains substantially zero ferrous material.

In this way, the first separation apparatus 2 can be seen as a "screening", or an initial extraction of as much ferrous as possible from the waste material 5, without being overly concerned by the presence of any non-ferrous in the first output 8.

As such, in exemplary embodiments, the first output 8 includes a majority of ferrous, but also many undesirable contaminants (e.g. hybrid materials, clumps, non-metals and non-ferrous that is collected along with the flow of ferrous collected by the first rotating drum 7). Such an arrangement reduces the likelihood that any valuable ferrous material is lost during processing in the first separation apparatus 2.

It should be understood that no separation is perfect, and so the third output 9 will contain some ferrous material. As such, "substantially zero" should be taken to mean that a negligible fraction of the third output 8 contains ferrous material that was not magnetically collected by the first drum 7 (e.g. it may have been clumped with a large non-ferrous or non-metal material).

It should be appreciated that the first separation apparatus 2 may be configured to obtain the above result using a separation characteristic based on any one or combination the above discussed parameters.

An exemplary embodiment of configuring the first separation apparatus 2 includes the parameters indicated in Table 1. The table indicates preferable operating ranges as well as exemplary operating values.

Table.1

Parameter Preferable Operating Range Value Strength of stationary magnet at drum surface 400 to 3000 G 1900 G Speed of drum 1 to 20 RPM 10 RPM Direction of rotation of drum (i.e. overfed or underfed) Overfed Relative position of stationary magnet Adjacent first flow path Clearance 100 to 500 mm 370 mm Flow path movement speed 0.1 to 1 m 5-1- 0.3 m s-1 In exemplary embodiments, the separation characteristic of the second separation apparatus 3 is such that the fourth output 13 contains ferrous material and non-ferrous material. The separation characteristic is also configured such that the ferrous material in the second output 12 is less dense or lighter than the ferrous material in the fourth output 13.

It should be understood that reference to the density or mass of an output is not in relation to the output as a whole, but rather relates to the average density or mass of ferrous material in the output. In this way, the fourth output 13 can be seen as mostly containing ferrous material that has a higher mass/density (e.g. solid blocks of material), whereas the second output 12 can be seen as mostly containing ferrous materials of a lower mass/density (e.g. sheet material).

While the second drum 11 is configured to collect a significant amount of ferrous material and thus the first output 8 is further refined, the drum 11 can also be configured such that the ferrous material of the first output 8 is separated based on the density or mass of the ferrous material and/or the magnetic strength of the material.

Separating in such a way means that the ligher (e.g. less dense) materials in the second output 12 can collected separately from the heavier (e.g. denser) materials in the fourth output 13. In this way, the ferrous material itself can be separated for re-use in different applications. Moreover, denser or heavier ferrous material (e.g. cast iron, steel lumps) that is difficult for a magnet to collect can be processed separately from less dense or lighter ferrous (e.g. steel sheets). As such, the final product from the system 1 is purer and can be provided sub-divided into different types of ferrous materials.

An exemplary embodiment of configuring the second separation apparatus 3 includes the operational parameters indicated in Table 2. The table indicates preferable operating ranges as well as exemplary operating values.

Table 2

Parameter Preferable Operating Range Value Strength of stationary magnet at drum surface 100 to 2000 G 910 G Speed of drum 10 to 30 RPM 19 RPM Direction of rotation of drum (i.e. overfed or underfed) Overfed Relative position of stationary magnet Adjacent second flow path Clearance 100 to 500 mm 370 mm Flow path movement speed 0.5 to 5 m s-' 1.65 m s' In exemplary embodiments, the parameters of Table 1 can be implemented alongside the parameters of Table 2. The resulting system 1 can effectively process the flow of waste material 5 by operating the first separation apparatus 2 as a "screening" step, and operating the second separation apparatus 3 as a "fine-tuning" step.

In this way, a concentration or fraction of ferrous material in the first output 2 is lower than a concentration or fraction of ferrous material in the second output 12. The combination of the two apparatus serves to both prevent the loss of significant amounts of ferrous material (i.e. in the third output 9), while also increasing the purity of the final product in the second output 12.

As noted above, the system 1 includes a third separation apparatus 4 for processing the fourth output 13 from the second separation apparatus 3 in the illustrated embodiment.

The third separation apparatus 4 will now be discussed in detail with reference to Figure 1 and Figure 3.

As can be seen in Figure 1, the third separation apparatus 4 has many features in common with the first and second separation apparatus 2, 3. In particular, the third separation apparatus 4 includes a third flow path 17 configured to transport the fourth output 13. The third separation apparatus 4 includes a third rotating drum 18 configured to magnetically collect a fifth output 19 of material from the fourth output 13.

The third rotating drum 18 can move the fifth output 19 out of the third separation apparatus 4. In the illustrated embodiment, the fifth output 19 is moved from the drum 18 to a product flow path 22. The fifth output 19 can be moved to a collection area via the product flow path 22, e.g. into drums for sale of the output 19, or may be moved for additional processing downstream. In alternative embodiments, the product flow path 22 is not present and the fifth output 19 moves from the rotating drum 18 to a receptacle or bin.

The third separation apparatus 4 can generate an additional output, referred to as a sixth output 23. In this way, the third separation apparatus 4 can be seen as separation separating the fourth output 13 into the fifth output 19 and the sixth output 23.

The sixth output 23 is defined as material remaining from the fourth output 13 after the fifth output 19 is collected by the drum 18. Put another way, while the fifth output 19 is defined by materials from the fourth output 13 magnetically collected by the third rotating drum 18, the sixth output 23 is defined by materials from the fourth output 13 that are not magnetically collected by the third rotating drum 18.

The third separation apparatus 4 is configured so as to have a separation characteristic different from that of the first and second separation apparatus 2, 3. In this way, the ferrous content of the fifth output 19 is different from the ferrous content of the first output 8 and the second output 12.

More particularly, in exemplary embodiments, the third separation apparatus 4 has a separation characteristic that results in the fifth output 19 having a higher purity (or concentration, or fraction) of ferrous than the first output 8. Moreover, the fifth output 19 can contain ferrous material of a higher mass or density compared with the ferrous material of the second output 12.

The third separation apparatus 4 is particularly advantageous in further improving the value of the products extracted in the system from the flow of waste material 5.

Specifically, the third separation apparatus 4 serves to further refine the fourth output 13.

Such is particularly advantage since the fourth output 13 may contain ferrous material that is particularly difficult to extract (e.g. ferrous material that is particularly dense or heavy). In this way, the third separation apparatus 4 can be configured to specifically target this difficult-to-extract ferrous.

It should be understood that the third separation apparatus 4 may be configured in any means to compliment the configuration of the first and second apparatus 2, 3.

It is advantageous for the third separation apparatus 4 to be arranged in an elevated position relative to the ground. In this way, the sixth output 23 can fall under gravity for collection, e.g. for disposal or processing elsewhere. It should be understood that the third separation apparatus 4 may be arranged in at any elevation relative to the ground or the other apparatus.

In Figure 1, the fourth output 13 is transported directly to the third separation apparatus 4, i.e. without any additional processing therebetween. It should be appreciated that in alternative embodiments, additional processing of the fourth output 13 may occur between the second apparatus 3 and the third apparatus 4.

For example, in some embodiments, it has been found to be advantageous to implement a purification apparatus (not shown) between the two apparatus. The purification apparatus may include a manual (e.g. operators picking materials from the output) or automated process (e.g. a robotic system for picking materials) of removing impurities from the output 13. Such an arrangement can be particularly advantageous in removing materials that are likely to become entangled with the materials in the output 13, e.g. copper wire. In this way, the effectiveness of the third apparatus 4 and thus the quality of the final product 19 can be improved.

A purification apparatus may also be included for downstream treatment of the second output 12 or the fifth output 19 in some embodiments, so as to improve the purity of the products. However, in exemplary embodiments, the system 1 is operable so as to achieve a high purity of ferrous in the products 12, 19 without the need for a purification apparatus.

Referring to Figure 3, an exemplary third separation apparatus 4 is indicated in more detail. Only the significant differences between the first 2 and the third separation apparatus 4 will be discussed.

The third rotating drum 18 is in the form of a third drum magnet having a rotatable shell 20 and a stationary magnet 21 within the rotatable shell 20.

Similarly to the first and second apparatus 2, 3, the separation characteristic of the third separation apparatus 4 is a function of at least one of: the strength of the stationary magnet 21, the relationship between the speed at which the shell 20 rotates and a movement speed of the third flow path 17, a clearance between the third drum 18 and the third flow path 17, a direction of rotation of the shell 20 about a longitudinal axis of the drum 18, a relative position of the magnet 21 within the shell 20 and a movement speed of the third flow path 17.

As indicated by the arrows on the drum 18 in Figure 3, the direction of rotation of the shell 20 of the third drum 18 about a longitudinal axis of the drum 18 is such that the fifth output is collected by and flows under or beneath the third drum 18. As noted above, such a configuration can be referred to as the drum 18 being "underfed".

Put another way, the material collected by the drum 18 can be seen as flowing with the drum (e.g. adhered to a surface thereof, or flowing close to such a surface) in the direction of rotation of the shell 20.

The arrangement has been found to reduce the amount of non-ferrous material being erroneously collected by the drum 18. Specifically, since the material has to move under the drum 18, the downward force of gravity on the material is in conflict with the upward force from the magnet 21. In exemplary embodiments, if material has erroneously been collected by the drum 18 (for instance because it is non-ferrous material clumped with another ferrous material), then it is likely to fall under gravity before it is moved to the final output with the ferrous material. As such, the purity and thus value of the final product is improved.

In some embodiments, the magnet 21 of the third rotating drum 18 can include multiple adjacent magnets arranged with alternating magnetic poles. In this way, as material moves with the shell 20 of the drum 18 adjacent to the magnet 21, the magnetic poles of the magnet continuously change. The changing magnetic poles can cause material adhered to the shell 20 to be rotated or "flipped" as it moves over the drum 18 surface (i.e. as it is attracted to one pole, but not to the next, and then attracted to the pole after etc.).

The continuous flipping of the material as it passes over the shell 20 increases the likelihood that any non-ferrous material erroneously collected is detached from the drum 18, thus increasing the purity of the final product 19. Moreover, the arrangement facilitates further separation of ferrous material by mass and/or by the magnetism of the material (i.e. because material with a stronger attraction to the magnet is less likely to fall).

In exemplary embodiments of the kind illustrated, the third drum 18 is configured such that the magnet 21 is positioned within the external shell so as to be adjacent an underside surface of the shell 20. Put another way, the magnet 21 is positioned within the shell 20 adjacent a surface of the shell closest to (or proximate) the ground.

In this way, a stronger magnetic field is generated about a lower side of the shell 20 when compared with the magnetic field at an upper side of the shell 20.

Positioning the magnet in such a way increases the influence magnetic strength of the components of the fourth output 13 have on the separation. Since the magnet 21 is closer to an underside of the shell 20, and the shell 20 rotates to take the collected material thereunder, ferrous material will be attracted to a lower surface of the shell 20 and so will be exposed to the force of gravity.

The influence of the force of gravity on the separation assists in reducing the non-ferrous material collected in the fifth output 19. More specifically, only material that is suitably attracted to the magnetic field of the drum 18 will overcome the downward force of gravity and move with the drum 18 to the output 19.

As such, any material that has been erroneously collected by the third drum 18 (e.g. nonferrous) will be more likely to fall under gravity before being fed to the final output as the fifth output 19. The arrangement has been found to improve the purity of the final product.

Typically, the magnet 21 of third rotating drum 18 is configured to generate a Gauss in the range of 100 to 3000 G at a surface of the third drum (e.g. 210 G, 770 G), preferably in the range of 500 to 2500 G, more preferably in the range of 1000 to 2000 G, more preferably in the range of 1500 to 1800 G. In exemplary embodiments, the magnet 21 of the third rotating drum 18 is configured to generate a Gauss of 1700 G at a drum 18 surface.

In exemplary embodiments, the stationary magnet 21 of the third rotating drum 18 has a greater strength than the stationary magnet of the second rotating drum 11. Such is particularly advantageous in assisting the third rotating drum 18 in extracting heavy ferrous materials from the fourth output 13.

Specifically, the combination of the relatively high strength of the magnet 21, the direction of rotation of the drum 18 and the position of the magnet 21 therein serves to significantly reduce the erroneous collection of non-ferrous material (as discussed above), while also reducing the likelihood that particularly heavy ferrous material falls under gravity (i.e. because the strength of the magnet increases the force of attraction between the material and the magnet 21).

Typically, the third drum is configured to rotate at a speed in the range of 10 to 30 RPM (e.g. 10 RPM, 11 RPM, 12 RPM, 12.3 RPM etc.), preferably in the range of 15 to 25 RPM (e.g. 24.6 RPM), more preferably in the range of 20 to 25 RPM.

In exemplary embodiments, the third drum 18 is preferably configured to rotate at a speed of 21 RPM and the third flow path 17 is configured to operate with a surface speed of 1.8 m 5-1 Typically, the third flow path 17 is configured to operate with a surface speed in the range of 0.5 and 5 m s-1, preferably in the range of 1 and 3 m s-1, (e.g. 1 m s, 1.5 m s-1, 2 m s-1, 2.5 m s-1, 3 m s-1), more preferably in the range of 1 and 2.5 m s.

In exemplary embodiments, the third flow path 17 is configured to operate with a surface speed of 1.8 m It should be understood that the third flow path 17 can be in any suitable form to transport material through the system 1. In exemplary embodiments, the third flow path 17 is provided as a third conveyor (i.e. so the above mentioned surface speed it the speed of movement of a belt of the conveyor).

The greater speed of the third conveyor allows even greater distribution of the fourth output 13 on the third conveyor (i.e. compared with the distribution of the first output 8 on the second conveyor). In this way, the ease at which the material in the fourth output 13 can be liberated from the flow path 17 is improved (i.e. because the material is less likely to be clumped). Such a configuration is particularly advantageous when the third separation apparatus 4 is intended to process particularly dense and heavy ferrous material that is typically difficult to liberate.

In exemplary embodiments, the clearance between the third drum 18 and the third flow path 17 is in the range of 100 and 500 mm, preferably in the range of 200 and 400 mm, more preferably in the range of 250 and 350 mm.

In exemplary embodiments, the clearance between the third drum 18 and the third flow path is 300 mm.

An exemplary embodiment of configuring the third separation apparatus 4 includes the operational parameters indicated in Table 3. The table indicates preferable operating ranges as well as exemplary operating values.

Table 3

Parameter Preferable Operating Value Range Strength of stationary magnet at drum surface 100 to 3000 G 1700 G Speed of drum 10 to 30 RPM 21 RPM Direction of rotation of drum (i.e. overfed or underfed) Underfed Relative position of stationary magnet Adjacent underside of rotating drum Clearance 100 to 500 mm 300 mm Flow path movement speed 0.5 to 5 m s-1 1.8 m s-1 It should be understood that any combination of the parameters indicated in Tables 1, 2 and 3 could be utilised during operation of the system 1.

Operating the system 1 based on the parameters indicated in the "Value" column of Tables 1-3 has been found to provide an exemplary mode of operation in which the purity of the final products is appropriate for re-use. However, it should be appreciated that any combination of parameters may be utilised based on the operational needs of the system 1.

While a number of parameters influencing the separation characteristics have been discussed, it should be understood that any one or combination may be utilised.

It should be understood that the outputs of each separation stage or apparatus differ chemically from one another. Put another way, if the component parts of one output were melted down and turned into an alloy, such an alloy would be chemically different than a respective alloy formed from another output.

For example, an alloy made of the component parts of the second output 12 would differ chemically from an alloy made of the component parts of the first output 8.

In exemplary embodiments, the system 1 is configured such that an alloy made of the component parts of the second output 12 differs chemically from an alloy made of the component parts of the fifth output 19.

In exemplary embodiments, the separation characteristic of at least one of the apparatuses 2, 3, 4 is variable based on a predetermined output or based on a characteristic of the flow of waste material 5 (i.e. the input to the system 1).

In this way, the system 1 can be manipulated to extract a wide variety of outputs (e.g. having different chemical properties), or to separate a wide variety of inputs, depending on the demand for a certain type of product, or the input into the process. Such can improve flexibility of the method, thus preventing any equipment becoming obsolete if demand for a certain material changes, or if a different input is to be separated.

The predetermined output can be based on any one of a desired purity of ferrous material in the second output 12 and/or the fifth output 19, a desired density of ferrous material in the second output 12 and/or the fifth output 19, a desired mass of ferrous material in the second output 12 and/or the fifth output 19.

The flexibility of the system 1 facilitates the type of ferrous material extracted from the process to be selected by manipulating the separation characteristic of a system 2, 3, 4. In this way, the need for any additional processing can be alleviated if, for example, the demand for a certain material changes, or if purity requirements change.

The system 1 includes a pre-treatment apparatus (not shown) in some embodiments. The pre-treatment apparatus is positioned upstream of the first separation apparatus 2. The pre-treatment apparatus is configured to shred, grind or otherwise fragmented the flow of waste material 5 before the material 5 is transported to the first separation apparatus 2.

The pre-treatment apparatus can include a shredder, a grinder, a chipper, a granulator, a pulveriser, a hammer mill, a ball mill, or any equipment that can reduce the particle size of the material in the flow of waste material 5.

Reducing the particle size of the flow of waste material 5 has been found to reduce the likelihood that material will not be liberated from other material types or clump together and be mistakenly collected/not collected by any of the drums in the separation apparatus 2, 3, 4. Having the ferrous material in the form of smaller particles has been found to increase the ease at which the drums 7, 11, 18 magnetically collect the material, as the smaller particles are easier to liberate from the flow of waste material 5. The greater surface area to weight ratio of the waste improves the efficiency of the overall separation, and thus the purity of the final product.

The pre-treatment apparatus can include a screening means that is configured to screen the shredded, ground, or fragmented waste material so as to prevent particles that are too large from being transported to the first separation apparatus 2.

The screening means can be in the form of a screen or grid having apertures sized

according to the specifications of the system 1.

It has been found that the screening ensures the material is shredded, ground, or fragmented to a suitable size for processing in the system 1, thereby facilitating effective separation of the material.

Typically, the apertures each define an area in the range of 60-250 mm by 60-250 mm, preferably in the range of 100-200 mm by 100-200 mm.

In exemplary embodiments, the apertures each define an area of 150 mm by 150 mm, such that material having a larger surface area is prevented from passing therethrough. In this way, the flow of waste materials 5 that is transported along the first flow path 6 contains materials that have passed through a 150 mm by 150 mm aperture.

The specific aperture size has been found to provide waste at an optimum size for the system 1. While reducing the particle size further may result in improved liberation of ferrous material, shredding, grinding, or fragmenting the waste material is an expensive process. As such, an aperture size of 150 mm by 150 mm has been found to provide the optimum balance between reducing operational costs whilst ensuring good liberation of the ferrous material.

It should be understood that the aperture size may vary in some embodiments. For example, it may be preferable to have apertures smaller than 150 mm by 150 mm in some embodiments. A smaller aperture size will result in smaller particles and thus improved liberation of the ferrous material.

The pre-treatment apparatus can include a cleaning means in exemplary embodiments.

The cleaning means can be positioned so as to clean the material that has been shredded, ground, or fragmented before transporting the material to the first separation apparatus 2.

In exemplary embodiments, the cleaning means includes an air suction system (e.g. a vacuum system) that is configured to suction contaminants away from the material with the air.

In exemplary embodiments, the cleaning means is positioned downstream of the screen. In this way, only the material intended to be treated in the system 1 (i.e. the material of the appropriate particle size) is cleaned.

The cleaning means is configured to remove/reduce the presence of contaminants from the material, e.g. dirt, small bits of plastic, wood chips etc. The cleaning means improves the quality of the output from the system 1, improving their suitability of re-use and/or sale. Moreover, the cleaning means reduces the amount of downstream treatment the separated outputs require before being suitable for re-use, and thus improves the value of the output.

The present teachings also relate to a method 101 of processing a flow of waste material 5, as shown in Figure 4.

The method includes a first separation stage 102 and a second separation stage 103. The first and second separation stages 102, 103 can correspond to the processing of material through the respective first and second separation apparatus 2, 3.

In this way, the input to the first separation stage 102 is equivalent to the flow of waste material 5. The first separation stage 102 is configured to generate the first output 8.

Similarly, the inlet to the second separation stage 103 is the first output 8. The second separation stage 103 is configured to produce the second output 12.

As discussed in relation to the first and second separation systems 2, 3, the first separation stage 102 is configured to separate the flow of waste material 5 into the first output 8 and the third output 9.

Similarly, the second separation stage 103 is configured to generate an additional output equivalent to the fourth output 13.

Each of the first and second separation stages 102, 103 can be configured with a separation characteristic different from the other such that the first 8 and second 12 outputs have different ferrous contents, as discussed above in relation to the first and second separation apparatus 2, 3.

As shown in Figure 4, the method 101 can also include a third separation stage 104. It should be understood that the method may only include first and second separation stages 102, 103 in some embodiments.

The third separation stage 104 is defined by the processing of material through the third separation apparatus 4. In this way, the third separation stage 104 is configured to separate the fourth output 13 into the fifth output 19, and the sixth output 23.

As shown in Figure 4, the method 101 includes a pre-treatment step 124. The pretreatment step 124 can include any configuration of a shredding/grinding/fragmenting step, a screening step, and a cleaning step as discussed above.

It should be understood that any configurations of the system 1 discussed above may be applied to the method 101.

The parameter values quoted for configuring the system 1 have been found to be particularly useful in processing a combination of ferrous and non-ferrous materials from a particular source, namely from shredded automobiles. However, it should be appreciated that the quoted parameters may be applicable to combinations of waste and non-ferrous waste from other sources.

Although the teachings have been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope as defined in the appended claims.

Claims

Claims 1. A method of processing a flow of waste material, the method comprising: a first separation stage comprising transporting a flow of waste material along a first mechanical flow path, wherein a first rotating drum is arranged adjacent the first mechanical flow path and is configured to magnetically collect a first output of material from said flow, the first output comprising ferrous material; and a second separation stage comprising transporting the material from the first output along a second mechanical flow path, wherein a second rotating drum is arranged adjacent the second mechanical flow path and is configured to magnetically collect a second output of material from the first output, the second output comprising ferrous material; wherein each separation stage is configured with a separation characteristic different from the other such that the ferrous content of the first output is different from the ferrous content of the second output; and wherein the first and second rotating drums are first and second drum magnets, each comprising a rotatable shell and a stationary magnet within the rotatable shell, wherein the separation characteristic of each stage comprises a function of at least the strength of each respective stationary magnet, and wherein the stationary magnet of the first rotating drum has a greater strength than the stationary magnet of the second rotating drum.
2. The method of claim 1, wherein the magnet of the first rotating drum has a greater Gauss than the magnet of the second rotating drum at a respective drum surface, wherein the magnet of the first rotating drum is configured to generate a Gauss in the range of 1800 G to 2000 G at a surface of the first drum, and wherein the magnet of the second rotating drum is configured to generate a Gauss in the range of 700 G to 1000 G at a surface of the second drum; optionally, wherein the magnet of the first rotating drum is configured to generate a Gauss of 1900 G at the surface of the first drum and the second rotating drum is configured to generate a Gauss of 910 G at the surface of the second drum.
3. The method of any preceding claim, wherein the separation characteristic of each stage comprises a function of the relationship between the speed at which each respective drum rotates and a movement speed of the respective mechanical flow path.
4. The method of claim 3, wherein the first drum is configured to rotate at a speed in the range of 5 to 15 RPM and wherein the second drum is configured to rotate at a speed of 15 to 20 RPM, and wherein the first mechanical flow path has a movement speed in the range of 0.1 to 1 m s-1 and the second mechanical flow path has a movement speed in the range of 1 to 2 m s-1; optionally, wherein the first drum is configured to rotate at a speed of 10 RPM and the second drum is configured to rotate at a speed of 19 RPM, and wherein the first flow path has a movement speed of 0.3 m-and the second flow path has a movement speed of 1.65 m s.
5. The method of any preceding claim, wherein the separation characteristic of each stage comprises a function of a movement speed of a respective mechanical flow path, wherein the second mechanical flow path is configured to operate at a greater speed than the first mechanical flow path.
6. The method according to claim 5, wherein the first flow path is provided by a first conveyor, and the second flow path is provided by a second conveyor, wherein at least the first conveyor is configured to vibrate, so as to disperse the waste material on the first conveyor.
7. The method of any preceding claim, wherein each of the first and second drums are configured to be spaced apart from the respective first and second flow paths so as to define a respective first and second clearance between the drum and respective flow path, and wherein the separation characteristic of each stage comprises a function of at least the respective clearance.
8. The method of any preceding claim, wherein the first separation stage produces the first output and a third output from the flow of waste material, wherein the third output is defined by material remaining from the flow of waste materials after the first output is magnetically collected, and wherein the separation characteristic of the first separation stage is configured such that the third output comprises substantially zero ferrous material.
9. The method of any preceding claim, wherein the second separation stage produces the second output and a fourth output from the first output of material, wherein the fourth output is defined by material remaining from the first output after the second output is magnetically collected, and wherein the separation characteristic of the second separation stage is configured such that the fourth output comprises ferrous material and non-ferrous material, and such that the ferrous material in the second output is lighter (e.g. has a lower average mass) than the ferrous material in the fourth output.
10. The method of claim 9, further comprising: a third separation stage comprising transporting the material from the fourth output along a third mechanical flow path, wherein a third rotating drum is arranged adjacent the third mechanical flow path and is configured to magnetically collect a fifth output of material from the fourth output, the fifth output comprising ferrous material; wherein the third separation stage has a separation characteristic different from that of the first and second separation stage such that the ferrous content of the fifth output is different from the ferrous content of the first and second output; and wherein the third rotating drum is a third drum magnet having a rotatable shell and a stationary magnet within the rotatable shell, wherein the separation characteristic of the third separation stage comprises a function of at least the strength of the stationary magnet of the third rotating drum, wherein the stationary magnet of the third rotating drum has a greater strength than the stationary magnet of the second rotating drum.
11. The method of claim 10, wherein the magnet of the third rotating drum has a greater Gauss than the magnet of the second rotating drum at a respective drum surface, wherein the magnet of the third rotating drum is configured to generate a Gauss in the range of 1000 to 2000 G at the surface of the drum.
12. The method of claim 10 or claim 11, wherein the separation characteristic of each stage comprises a function of at least a direction of rotation of the respective rotatable shell about a respective longitudinal axis of each drum magnet, wherein the direction of rotation of the first and second drum magnets is such that material is collected by and flows over the respective drum magnet, and wherein the direction of rotation of the third drum magnet is such that material is collected by and flows under the third drum magnet.
13. The method of claim 12, wherein the separation characteristic of each stage comprises a function of at least a relative position of the respective magnet within the shell, wherein the first drum magnet is configured such that the respective magnet is positioned within the shell so as to be adjacent the first flow path, wherein the second drum magnet is configured such that the respective magnet is positioned within the shell so as to be adjacent the second flow path, and wherein the third drum magnet is configured such that the magnet is positioned within the shell so as to be adjacent a surface of the shell proximal to ground level.
14. The method of any of claims 10 to 13, wherein the separation characteristic of the third separation stage comprises a function of the relationship between the speed at which the third drum rotates and a movement speed of the third mechanical flow path; optionally, wherein the third drum is configured to rotate at a speed in the range of 20 to 25 RPM and the third flow path has a movement speed in the range of 1 to 2.5 m
15. The method of any of claims 10 to 14, wherein the separation characteristic of the third separation stage comprises a function of a movement speed of the third mechanical flow path, wherein the third mechanical flow path is configured to operate at a greater speed than the second mechanical flow path.
16. The method of any of claims 10 to 15, wherein the separation characteristic of the third separation stage comprises a function of a clearance between the third drum and the third flow path.
17. The method of any preceding claim, further comprising a pre-treatment step, wherein the flow of waste material is shredded, ground, or otherwise fragmented before being transported along the first flow path.
18. The method of claim 17, wherein the pre-treatment step further comprises a screening step in which the shredded, ground or fragmented waste material is screened by a grid having a plurality of apertures before being transported along the first flow path; optionally, wherein the apertures have an area of 150 mm by 150 mm.
19. The method of claim 17 or claim 18, wherein the pre-treatment step further comprises a cleaning step, in which the shredded, ground or fragmented waste material is cleaned such that contaminants can be removed from the waste material before transporting the material along the first flow path; optionally, wherein the cleaning step includes subjecting the shredded, ground or fragmented waste material to a suction of air, such that contaminants material can be suctioned away by the air; optionally, wherein the cleaning step is after the screening step.
20. The method of any preceding claim, wherein the first output is transported directly from the first separation stage to the second separation stage via the second mechanical flow path.
21. The method of any preceding claim, wherein the separation characteristic of at least one of the separation stages is variable based on a predetermined output or based on a characteristic of the flow of waste material.
22. The method of claim 21, wherein the predetermined output is based on at least one of: a desired purity of ferrous material in the second output, a desired density of ferrous material in the second output, and a desired mass of ferrous material in the second output; optionally, wherein the predetermined output is based on at least one of: a desired purity of ferrous material in the fifth output, a desired density of ferrous material in the fifth output, and a desired mass of ferrous material in the fifth output.
23. A system for processing a flow of waste material, the system comprising: a first separation apparatus comprising a first mechanical flow path configured to transport waste material, and a first rotating drum arranged adjacent the first flow path, the first rotating drum configured to magnetically collect a first output of material from said flow, the first output comprising ferrous material; and a second separation apparatus comprising a second mechanical flow path configured to transport the first output, and a second rotating drum arranged adjacent the second flow path, the second rotating drum configured to magnetically collect a second output of material from the first output, the second output comprising ferrous material; wherein each separation apparatus is configured with a separation characteristic different from the other such that the ferrous content of the first output is different from the ferrous content of the second output; and wherein the first and second rotating drums are first and second drum magnets, each comprising a rotatable shell and a stationary magnet within the rotatable shell, wherein the separation characteristic of each apparatus comprises a function of at least the strength of each respective stationary magnet, and wherein the stationary magnet of the first rotating drum has a greater strength than the stationary magnet of the second rotating drum.