Method and apparatus for recovering a composite mill liner

Abstract

The invention relates to a method and apparatus for recycling a composite mill liner. The invention preferably relates to an optimized method for recovering worn composite material mill liners by effectively detaching composite materials into reusable metal and rubber parts, and to a mobile device for carrying out the method.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for recycling composite mill linings. The present invention preferably relates to an optimized method for recycling worn composite material mill linings by effectively disassembling the composite material into reusable metal and rubber components, and a mobile device for implementing the method. Background Art

[0002] Composite mill linings are high-performance lightweight mill linings that are uniquely constructed with rubber and metal inserts. It combines the advantages of steel linings and the flexibility of rubber linings. Each grinding mill lining application has different characteristics and requires a unique composite mill lining with better grinding performance and longer lining life. Used mill linings are heavy structures, weighing between 1 ton and 4 tons. Currently, used / worn mill linings are discarded in landfills and constitute an important part of solid waste. Both metal components and rubber have good recycling value as recyclable materials, and some parts of the metal, especially the substrate that is not worn during mill operation, have high reuse value. However, due to the inherent nature of heterogeneity, especially the different characteristics of different linings, recycling mill linings has been a huge challenge so far. To achieve the current goals of sustainability in mining and cement engineering, recycling and reusing end-of-life products such as mill linings is essential. Recycling will ultimately lead to savings in resources and energy.

[0003] So far, no commercial technology for successfully recycling composite mill linings on a large scale has been reported. The lack of sufficient equipment, high recycling costs, and low quality of recycled materials may be the main commercialization barriers. To promote composite material recycling, extensive research and development efforts are still needed to develop better recyclable composite materials with breakthroughs and more effective separation technologies.

[0004] However, the recycling of tires made of composite materials has been discussed in patent disclosures. In particular, in the field of the treatment and recycling of tires (mainly waste tires), the commonly used conventional method is to burn the rubber part in an incinerator and clamp the core metal remaining after incineration; or mechanically pull out the metal wires from the rubber and cut the rubber part for recycling.

[0005] CN201721031959 provides a technical solution for recycling tires, which increases the temperature of the wire part of the rubber by passing an electric current through it, which separates the wire part from the rubber part. The disadvantage of this solution is that for each waste tire to be processed, the electrodes are connected to both ends of the steel wire in the tire, and there are many operating steps, which is not conducive to the large-scale treatment of waste tires.

[0006] U.S. Patent No. 6,979,384 proposed the induction heating of waste tires. First, the waste outer tire of the tire is divided into a tread ring, sidewalls, and bead parts. Then, the tread ring (with the tread pattern on the outside) is guided on a rotating guide drum around an inductor. Thus, the metal reinforcing wire is gradually inductively heated, and the nearby rubber degrades to form gaseous products. Then, the metal reinforcement is gradually released on the curved guide drum and separated from the rubber parts. The main problem here is the non-uniform heating of the metal reinforcement, which is because the tread ring only passes under the inductor on one side, and the high-frequency field with a constant intensity given by the inductor device cannot ensure uniform inductive heating of the metal reinforcement across the entire width of the strip. The edge parts of the reinforcement are less heated, which of course is reflected in the quality of the separation of the composite layer.

[0007] U.S. Patent Application Publication No. 2004 / 0173699A1 aims to provide a method and device for tire recycling that can simply and quickly process waste tires and obtain cut rubber blocks that can be reused as useful rubber materials. The method and device include cutting the circumferential surface of the tire to a predetermined depth by a rotating cylinder, and then separating the metal reinforcing components embedded in the tire from the rubber components by RF induction heating. The rotating cylinder has cutting blades each in the shape of a rhombic flat plate, and the RF induction heating decomposes and carbonizes the rubber part adjacent to the heated metal part. The cutting performed by the rhombic blades in the basic part of the present disclosure enables smooth and effective removal of the surface tire layer, thus facilitating subsequent RF heating and producing useful cut rubber suitable for obtaining variable recycled materials.

[0008] The methods and devices discussed in the above prior art documents have several significant drawbacks for applications in mill linings. The basic drawback is that the mill lining is a heavy structure with large metal reinforcements and a metal substrate. Therefore, the methods and devices are only applicable to recycling whole tires and the fine metal wires embedded in the tires. Another drawback is that the induction heating coil is located around the outer circumferential surface of the tire in the radial direction, making it close to the surface layer of the tire. This arrangement cannot ensure uniform inductive heating of the metal reinforcement of the mill lining across its entire width.

[0009] Therefore, an object of the present invention is to provide a method for disassembling metal and rubber parts from a composite mill lining, mainly a used / worn mill lining, which, due to its simplicity and versatility, will enable ensuring a high capacity of the recycling method, thereby recycling recyclable parts.

[0010] Another object of the present invention is to provide a device for recycling metal and rubber parts from a composite mill lining, mainly a used / worn mill lining, which, due to its simplicity and versatility, will enable ensuring a high capacity of the recycling method, thereby recycling recyclable parts. Summary of the Invention

[0011] According to the present invention, the set object is achieved by a method for separating metal reinforcement from a rubber - metal composite of a used mill lining, the method comprising:

[0012] a) Radiating the metal components embedded in the mill lining by gradually passing the composite material part along its length or outer circumference through a high - frequency induction field to inductively heat the metal reinforcement over the entire width of the composite material, thereby transferring energy sufficient to pyrolyze the thin rubber layer in contact with the metal surface, causing the metal to be released from the rubber matrix;

[0013] b) Separating the metal components from the rubber part of the composite material, including secondary mechanical separation to pull the metal components out of the composite mill lining.

[0014] According to the method of the present invention, the metal components are optionally radiated by passing the composite part one or more times through the induction field, and different metal components are pulled out of the composite mill lining after each pass - step b).

[0015] According to the method of the present invention, radiating the metal components embedded in the mill lining heats the metal surface to a temperature between 450 °C and 650 °C, preferably between 500 °C and 600 °C, most preferably between 500 °C and 550 °C, whereby the primer, adhesive, and thin layer of rubber on the steel surface pyrolyze into gases, fumes, and solid carbon - rich compounds such as coke, carbon black, and graphite.

[0016] According to the method of the present invention, the method further includes a step of controlling the heating rate to minimize the degradation of both the rubber and the metal, thereby maintaining the optimal performance for material recycling or metal component refurbishment.

[0017] According to the method of the present invention, the heating rate is controlled by the speed at which the composite mill lining is fed through the induction field.

[0018] According to the method of the present invention, the heating rate is controlled by changing the power of the induction field such that different parts of the metal component are heated at different rates as they pass through the induction field.

[0019] According to the method of the present invention, the heating rate is controlled by the geometry of the inductor coil, which focuses the induction field at certain parts of the metal component as the metal component passes through the induction field.

[0020] According to the method of the present invention, the heating rate is controlled by an external magnetic material, which focuses the induction field at certain parts of the metal component as the metal component passes through the induction field.

[0021] The method according to the present invention, wherein the heating rate is controlled by any combination of the methods for controlling the heating rate.

[0022] The method according to the present invention, wherein the step of separating the metal component from the rubber part involving secondary mechanical separation includes vibrating, shaking, milling, dropping, hammering, pushing or pulling operations.

[0023] The method according to the present invention, wherein the method further includes the step of sorting the rubber and metal components after induction heating.

[0024] The method according to the present invention, wherein another step for sorting the rubber and metal components after induction heating includes cutting, shredding and filtering operations.

[0025] The method according to the present invention, wherein another step for sorting the rubber and metal components after induction heating includes gravity separation.

[0026] The method according to the present invention, wherein another step for sorting the rubber and metal components after induction heating includes magnetic separation.

[0027] The method according to the present invention, wherein another step for sorting the rubber and metal components after induction heating combines any one of the methods for sorting rubber and metal.

[0028] The method according to the present invention, wherein the method further includes steps for avoiding the generation of smoke, exhaust gas and coal particles during induction heating.

[0029] The method according to the present invention, wherein another step for avoiding the generation of smoke, exhaust gas and coal particles during induction heating includes ventilation in the form of suction above the heating zone.

[0030] The method according to the present invention, wherein another step for avoiding the generation of flue gas, exhaust gas and coal particles during induction heating includes a blower, such as a fan or a centrifugal blower, which is placed such that the flue gas, exhaust gas and coal particles are blown away from the heating zone.

[0031] The method according to the present invention, wherein another step for avoiding the generation of flue gas, exhaust gas and coal particles during induction heating includes a shroud or cabinet for guiding the air flow such that the flue gas, exhaust gas and coal particles are removed from the heating zone.

[0032] The method according to the present invention, wherein another step for avoiding the generation of flue gas, exhaust gas and coal particles during induction heating combines the methods to avoid flue gas, exhaust gas and coal particles.

[0033] A method according to the invention, wherein another step for avoiding smoke, exhaust gases and coal particles generated during induction heating reduces the concentration of combustible components in a region having a temperature above the flash point to be lower than a critical ignition limit described by a lower explosion limit (LEL for gases and vapors) or a minimum explosive concentration (MEC for powders).

[0034] A method according to the invention, wherein another step for avoiding flue gases, exhaust gases and coal particles generated during induction heating comprises using a non-oxidizing gas stream to displace oxygen in the heating zone.

[0035] A method according to the invention, wherein another step for avoiding smoke, exhaust gases and coal particles generated during induction heating comprises a filtration unit filtering particles from the discharged air or gas stream to prevent them from leaking into the open environment.

[0036] A method according to the invention, wherein the method further comprises a step for extinguishing a fire caused by flue gases, exhaust gases and coal particles generated during induction heating or by the rubber component itself.

[0037] A method according to the invention, wherein another step for fire extinguishing comprises a manual or semi-automatic or automatic fire suppression system above the heating zone.

[0038] A method according to the invention, wherein another step for fire extinguishing comprises a manual or semi-automatic or automatic fire suppression system above the heating zone, and extends partially or completely along the lining path such that a fire continuously present on either side of the heating zone can still be extinguished.

[0039] A method according to the invention, wherein the manual or semi-automatic or automatic fire suppression system consists of a carbon dioxide or other oxygen-displacing gas fire suppression system.

[0040] A method according to the invention, wherein the manual or semi-automatic or automatic fire suppression system consists of a water mist fire suppression system.

[0041] A method according to the invention, wherein the manual or semi-automatic or automatic fire suppression system is coupled to an electrical safety interruption or other shutdown control for the entire device.

[0042] A method according to the invention, wherein the manual or semi-automatic or automatic fire suppression system is coupled to a gas sensor and an alarm and a safety alarm for the operator.

[0043] A method according to the invention, wherein the metal components of the composite mill lining have magnetic or electrical properties.

[0044] A method according to the present invention, wherein the method includes a step of controlling the penetration of magnetic flux into the article such that it most effectively separates the rubber from the steel component.

[0045] A method according to the present invention, wherein the step of controlling the penetration of magnetic flux into the article includes using a magnetic shield around the inductor or placing a permanent magnet around the inductor or using a soft magnetic material including magnetic particles, for example, ferrite particles formed in a polymer matrix shaped to surround the inductor.

[0046] In another embodiment, the present invention also relates to an apparatus for separating metal reinforcement from a rubber - metal composite of a used mill lining, comprising:

[0047] a) An induction system including an inductor in the form of a coil designed to have one or more windings, the coil being in the shape of the cross - section of the mill lining to obtain optimal energy transfer sufficient to pyrolyze the thin rubber layer in contact with the metal surface and effectively separate the metal component from the composite mill lining;

[0048] b) An automatic conveying system for conveying the mill lining through the inductor; and

[0049] c) A secondary mechanical separation system for separating the metal component of the composite mill lining from the rubber portion.

[0050] An apparatus according to the present invention, wherein the apparatus further comprises:

[0051] d) An induction heating generator capable of outputting a power of 100 to 200 kW for inductively heating the metal reinforcement across the entire width of the composite material; and

[0052] e) A cooling system capable of cooling the power supply and the inductor, having safety interlocks and differential pressure monitoring for automatic locking of the induction heating source.

[0053] An apparatus according to the present invention, wherein the induction system further comprises any one of the following:

[0054] i) A ventilation system including a ventilator and a shroud, the shroud allowing an air flow of sufficient intensity to flow around the portion of the mill lining closest to the inductor to reduce the flue gas concentration to below the APEX limits;

[0055] Wherein close means the width of the inductor + 100 mm on both sides of the inductor.

[0056] ii) A magnetic shield for reducing the magnetic flux outside the induction system to zero;

[0057] iii) A control unit for controlling the speed at which the mill lining components move through the induction system;

[0058] iv) A focusing system that positions the mill lining components to pass through the induction system, which is suitable for different lining geometries.

[0059] The device according to the invention, wherein the ventilation system further includes a centrifugal fan that can blow away gases and fumes from the heating area to avoid ignition.

[0060] The device according to the invention, wherein the ventilation system can remove the generated waste gases, dust, and fumes from the heating area at a rate of 5 - 10 g / s, 10 - 25 g / s to avoid ignition.

[0061] The device according to the invention, wherein the ventilation system can ensure an air exchange of 1000 - 10,000 m 3 / hour around the part of the mill lining closest to the inductor.

[0062] The device according to the invention, wherein the inductor can achieve an energy transfer sufficient to raise the surface temperature of the steel component to between 500°C and 550°C, preferably between 500°C and 600°C; most preferably 500°C to 650°C, whereby a thin layer of primer, adhesive, and rubber on the steel surface pyrolyzes into gases, fumes, and solid carbon - rich compounds such as coke, carbon black, and graphite.

[0063] The device according to the invention, wherein the inductor is made of high - conductivity rectangular copper bars or tubes (99% purity or better). The coil should have sufficient flexibility to accommodate slight bending so that small errors in curvature can be corrected. The coil cross - section and number of turns are optimized to adapt to the power and frequency limitations of the induction heating power supply and the load circuit while maximizing the energy transfer to the steel components of the composite mill lining.

[0064] The device according to the invention, wherein the inductor is shaped to follow the geometry of the cross - section of the composite lining.

[0065] The device according to the invention, wherein the inductor is shaped to follow the geometry of the cross - section of the composite lining and has protrusions at sharp corners to reduce non - uniform heating.

[0066] The device according to the invention, wherein the inductor includes a housing, which is in the form of a metal shield or any other form that can withstand temperatures from 300°C to 650°C and allows controlled magnetic flux penetration into the article.

[0067] The device according to the invention, wherein the inductor includes a housing, which is in the form of a metal shield or can withstand temperatures from 300°C to 650°C, and allows any other form that can control and minimize the magnetic flux penetrating outside the article.

[0068] An apparatus according to the present invention, wherein the inductor is fixed by a non-metallic housing, and a permanent magnet or a high magnetic permeability component is distributed in the housing. In particular, high-conductivity particles are distributed in or around the housing to control the magnetic flux penetration into the article.

[0069] An apparatus according to the present invention, wherein the inductor is fixed by a non-metallic housing, and a part of the non-metallic material is filled with ferrite or other magnetic particles or other shaped fillers.

[0070] An apparatus according to the present invention, wherein the non-magnetic material is a heat-resistant thermoplastic or thermosetting material.

[0071] An apparatus according to the present invention, wherein the non-magnetic material is a heat-resistant thermoplastic or thermosetting material, which is formed to embed the inductor by molding, other plastic processing or tool processing techniques.

[0072] An apparatus according to the present invention, wherein the heat-resistant thermoplastic material is one or more of PEEK, PSS, PSU, powder polymer, PBI, polyimide, polyamide, polyaramide or other heat-resistant thermoplastic materials.

[0073] An apparatus according to the present invention, wherein the heat-resistant thermoplastic material is a composite material with non-metallic fillers or metal fillers smaller than the critical eddy current limit.

[0074] An apparatus according to the present invention, wherein the heat-resistant thermosetting material is one or more of silicone, modified silicone, epoxy thermosetting material, polyurethane or other heat-resistant thermosetting materials that can be cured by any means including heat, light or chemical reagents.

[0075] An apparatus according to the present invention, wherein the heat-resistant thermosetting material is a composite material with non-metallic fillers or metal fillers smaller than the critical eddy current limit.

[0076] An apparatus according to the present invention, wherein the non-magnetic material is wood or a wood composite, which is formed to embed the inductor by forming or tool processing techniques.

[0077] An apparatus according to the present invention, wherein the non-magnetic material is a ceramic material, which is formed to embed the inductor by forming, tool processing or molding techniques.

[0078] An apparatus according to the present invention, wherein the non-magnetic material is a refractory material, which is formed to protect mechanical components and the environment from the influence of heat.

[0079] An apparatus according to the present invention, wherein the secondary mechanical separation system includes a crane or a gripper, which is capable of lifting or shaking apart the metal and rubber components after the induction heating of the metal components.

[0080] The device according to the present invention, wherein the secondary mechanical separation system includes a vibrating machine that can vibrate and separate the metal and rubber components after the induction heating of the metal components.

[0081] The device according to the present invention, wherein the secondary mechanical separation system further includes a vibrating filter for filtering and collecting the carbon black dust and small rubber particles released from the secondary mechanical separation.

[0082] In a further embodiment, the present invention relates to a mobile recycling unit that includes the device as defined above contained in a container and deliverable to a desired location.

[0083] The device according to the present invention, wherein it is a mobile unit, and the device as defined above is housed in a container.

[0084] The device according to the present invention, wherein it is a mobile unit, and the device as defined above is contained in a container and operates when installed in the container.

[0085] The device according to the present invention, wherein it is a mobile unit, and the device as defined above is contained in a container and is operated after being deployed and installed outside the container.

[0086] The device according to the present invention, wherein it is a mobile unit, and the device as defined above is contained in a container, and operates after the components of the device are deployed and installed outside the container while other components operate inside the container.

[0087] The device according to the present invention, wherein the device is a mobile unit, and the induction system, the ventilation system, and the fire extinguishing system operate when installed in the container.

[0088] The device according to the present invention, wherein the container is open at both ends to allow for easy unpacking.

[0089] The device according to the present invention, wherein the container is open at both ends and on the sides to allow for easy access to the induction system, ventilation device, and fire extinguishing system installed in the container when operating the container.

[0090] The device according to the present invention, wherein the container is open at both ends to allow for easy loading and removal of the lining and partial assembly to the induction system, ventilation device, and fire extinguishing system installed in the container.

[0091] The device according to the present invention, wherein it is a mobile unit, and the device as defined above is housed in one or more containers.

[0092] An apparatus according to the present invention, wherein it is a mobile unit, wherein the apparatus as defined above is contained in one or more enclosures, and wherein one enclosure contains components installed and operative within the enclosure, and the remaining components are assembled to the enclosure components under deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Preferred embodiments of the present invention will be described in detail based on the drawings, wherein:

[0094] Figure 1 is a schematic illustration of an embodiment of an apparatus according to the present invention suitable for mobile applications. The components of the drawing are referenced in Table 1.

[0095] Table 1: Figure 1 Numbered components in.

[0096]

[0097]

[0098] Figure 2 is a schematic view of an embodiment of a separation station of an apparatus according to the present invention for removing steel components from a rubber matrix after debonding by induction heating, comprising:

[0099] a. A workbench or similar device (11), which is approximately 1 m × 1 m in size and is adjusted in height to receive a conveyor for the lining after induction heating. The workbench is fixed to the ground.

[0100] b. A switchable (switchable) or electromagnetic lifter (12) fixed to the workbench.

[0101] c. A bracket or other mechanical fastener that can hold the rubber or steel components fixed to the workbench (not shown).

[0102] d. A crane or elevator that can be equipped with a magnetic lifting head or gripper to hold the wear-resistant steel component and the rubber matrix.

[0103] Figure 3 is a schematic view of an embodiment of a ventilation cover (13) of an apparatus according to the present invention for generating a laminar flow around an inductor to blow away and suck away fumes, exhaust gases, and dust.

[0104] Figure 4 is a schematic view of an embodiment of a cover (13) with a top cover (14) and a sketch of the air flow within the ventilation cover. The inlet flow can be provided by a ventilator. The outlet suction is provided by another ventilator.

[0105] Figure 5It is a schematic diagram of an embodiment of a toroidal inductor coil (15) having three windings and a length of 100 mm. The length is the longitudinal direction passing through the liner of the coil. The inductor coil is shaped to follow the cross-section of the liner orthogonal to the longitudinal direction.

[0106] Figure 6 It is a schematic diagram of an embodiment of a flat inductor coil (16) having three windings and a length of 100 mm. The width of the coil covers the entire width of the substrate. The coil heats the substrate from below.

[0107] Figure 7 It is a schematic diagram of an embodiment of a steel component (17) and a rubber matrix (18) in a medium-sized composite sag mill liner (19).

[0108] The liner (19) is formed by molding the steel component (17) into the rubber matrix (18). The bond between the steel (17) and the rubber (18) holds the structure together.

[0109] Liner dimensions: 2020 mm x 931 mm x height

[0110] Height from below the center of the substrate: 250 mm at the hook.

[0111] Height from below the center of the substrate: 235 mm at the top of the ASTM A532 component.

[0112] Weight and materials from bottom to top:

[0113] Substrate ASTM A36 steel 122 kg x1

[0114] Rubber matrix 113.1 kg x1

[0115] AR 550HB steel 41.2 kg x4

[0116] AR 600HB steel 116.9 kg x2, including lifting hook

[0117] ASTM A532, IIB 73.7 kg x8

[0118] Figure 8 It is a schematic diagram of an exploded view of the liner components. All are steel components except for the rubber matrix. From bottom and upwards: substrate (20); molded rubber matrix (18); very hard wear-resistant steel component (17); wear-resistant steel lifter (21).

[0119] Figure 9 It is a schematic diagram of an embodiment of only the steel components of the liner. The rubber matrix is hidden to emphasize the surface heated by induction heating. Detailed Description

[0120] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0121] The present invention provides an optimized method for separating metal reinforcements from rubber-metal composite specimens, especially for separating metal reinforcements from used or worn mill linings. The essence of the present invention lies in the fact that the corresponding composite element is first gradually passed continuously through a high-frequency electromagnetic field over its entire length or circumference, which is driven by a power source with an output power of 75 to 200 kW. This causes the induction heating of the metal reinforcements over the entire width of the composite part and pyrolyzes the thin rubber layer that bonds the metal surface to the rubber, resulting in the initial release of the metal reinforcements from the rubber matrix. Then, the metal parts of the composite material are separated from the rubber part by secondary mechanical separation to pull the metal parts out of the composite mill lining.

[0122] The composite material parts to be recycled can be advantageously pre-adjusted by cutting them into relatively small pieces.

[0123] In the method and device according to the present invention, the induction field only penetrates into the surface layer of the conductive and magnetic materials. The heat is quickly transferred to the steel surface and heats it to above 300 °C. This causes the pyrolysis of the thin rubber layer in contact with the steel, thus creating a permanent slip between the rubber and the steel. Any primer or adhesive that adheres the rubber to the steel is removed during this process.

[0124] For many reasons, the induction heating method and device according to the present invention are the most suitable technologies for the mobile recycling solution of composite linings:

[0125] - The operations required for recycling the lining are relatively simple, and the material is rarely deteriorated during the heating operation.

[0126] - The temperature and heating time can be controlled within a range where the steel parts are little affected.

[0127] - The amount of rubber that needs to be pyrolyzed can be controlled to a minimum without affecting the properties of the remaining rubber.

[0128] - Some parts of the lining (e.g., the substrate) can be refurbished and reused.

[0129] The equipment for implementing the method according to the present invention mainly consists of a loading and unloading system, an induction heating system, and a secondary mechanical separation system. The loading and unloading system consists of a conveyor, a trolley, a pulley, or a skateboard, which can enable the composite material sample to pass through the area heated by the induction heating system. A crane, a lifter, or other devices for handling composite materials are also part of the loading and unloading system. The induction system consists of a power supply, one or more inductors, a matching unit, and a cooling unit. The induction system is provided with a ventilation and filtration system for removing smoke, dust, and exhaust gas during heating. The secondary mechanical separation system is provided with machines or mechanisms for removing the steel parts of the composite material from the rubber parts.

[0130] In certain embodiments, the equipment according to the present invention can be made into a mobile unit to be deployed at or near a mining site. In addition to the primary induction system and the separator system, the mobile unit further includes any of the following components:

[0131] - A packing case for accommodating all instruments and machinery, the components of which can be deployed in the open air at the mining site;

[0132] - A power supply for the boxed components of the machinery;

[0133] - Built-in ventilation options in the packing case

[0134] The composite material sample is passed through the area of the inductor that heats the metal part of the composite material. The composite material sample is oriented such that its length dimension passes through the heating area. The length dimension is characterized by a consistent or substantially consistent cross-section. The substantially consistent cross-section may not be orthogonal to the length direction.

[0135] The inductor consists of one or more coils, which are oriented such that the heating induction coil extends across the entire width of the lining. The number of turns and its length are matters of design optimization. Its geometry and the final housing can be based on a model optimized for the magnetic flux lines including permanent magnets using ferrite composites to uniformly direct the magnetic field lines into the lining structure.

[0136] A ventilation device for reducing the flue gas concentration below the ignition and explosion limits is also installed in the equipment to avoid flames.

[0137] After induction heating, the secondary process for separating the metal parts from the rubber parts of the mill lining includes shaking the lining until the steel and rubber are separated, and subsequently sorting the parts, for example, screening or lifting the steel parts with a lifting magnet.

[0138] In addition to the secondary treatment, a washing or filtering treatment is included to remove charcoal dust. A part of this operation can be carried out at a rubber recycling facility.

[0139] The logistics for packaging and transporting parts for recycling or refurbishment is also part of this disclosure.

[0140] In an embodiment of the invention, the inductor wire preferably has ferrite segments located in its edge regions, each 10 to 50 mm wide.

[0141] In another embodiment, the separator inductor is preferably equipped with a cooling system, and the separator as a whole is also equipped with a pneumatic control system and / or limit switches.

[0142] The method and device according to the invention optimize the known and principle-similar methods in the following aspects:

[0143] 1) Optimize the influence of the high-frequency electromagnetic field on the composite component: The high-frequency electromagnetic field is driven by a power supply with an output power of 75 to 200 kW. The frequency and power are optimized to raise the temperature of the steel component surface to a temperature of 500 °C to 550 °C within a few minutes. The temperature is optimized to provide rapid pyrolysis of the steel-rubber interface and, at the same time, not reduce the properties of the steel, such as hardness and microstructure. It is known that rubber pyrolyzes between 300 °C and 500 °C, while excess char burns in oxygen between 450 °C and 500 °C. Generally, rubber pyrolyzes at a lower temperature between 300 °C and 400 °C. The higher temperature allows precise control of the thickness of the rubber layer pyrolyzed on the surface at a higher degradation rate. The selection of the operating temperature range from 500 °C to 550 °C is considered optimal for the recycling mill lining in terms of time, temperature, energy consumption, and the preservation of material properties.

[0144] 2) The inductor designed according to the invention is in the form of a coil with one or more windings, and its shape is the same as the cross-section of the mill lining for optimal energy transfer. This is considered effective in pyrolyzing the thin rubber layer in contact with the metal surface, and the composite component in the middle of the inductor does not overheat, and there is no reheating at the edges.

[0145] 3) For heating the substrate of the composite lining, a flat plate-shaped coil is more effective. The coil should extend across the entire width of the substrate of the lining. It can have few windings (e.g., three windings) and a narrow length (e.g., 100 mm). The length is the extension of the coil in the length direction of the lining. The induction heating system should allow easy switching between coils.

[0146] The invention will be described more specifically based on examples, although the invention is in no way limited to or restricted by these examples.

[0147] Examples

[0148] Example 1: Demonstrate the separation of natural rubber and magnetic steel components; the temperature for pyrolyzing rubber; and the thickness of the pyrolyzed rubber layer required to debond the steel from the rubber.

[0149] 1.1 Methods and Instruments

[0150] Induction heating is carried out in an indoor device with a water-cooled induction heating station and a power supply from UltraFlex Power Technologies. The device is built into a fume hood. Additional suction is placed directly above the sample to remove smoke and gases during heating. An inductor coil with 6 windings and a length of 80 mm is used.

[0151] Induction heating system of UltraFlex Power Technologies Co., Ltd.:

[0152] Power supply: UltraFlex UPT-S2, rated current 12 Arms, rated power 2.5 kW, 50 - 250 kHz

[0153] Inductive heating device: UltraFlex HS-4, water-cooled

[0154] Inductor: Internally wound 6×1 mm copper tube, insulated with PTFE heat shrink. Length 80 mm, 6 windings, inner diameter 80 mm.

[0155] Induction heating is carried out at a frequency of 63 kHz and a 24x current conversion, allowing up to 240 A in the inductor. The load matching between the sample and the inductor is optimized to allow the power supply to operate close to its maximum performance by adjusting parameters to heat a bare steel rod. The instrument does not allow the reading of active power and reactive power, but an ABB electricity meter is coupled to the power supply to measure apparent power.

[0156] Electricity meter

[0157] ABB B21112-100

[0158] Data acquisition:

[0159] Labview program and instrument

[0160] Temperature sensor

[0161] Type K thermocouple from RS-Components

[0162] Thermogravimetric analysis (TGA):

[0163] TGA / SDTA851e from Mettler-Toledo

[0164] TGA analysis is performed on a piece of vulcanized rubber to track degradation during heating.

[0165] Initial measurements were made on the bare steel rods to adjust the instrument parameters to match the load between the power supply, inductor, and sample. The adjustable parameters were the frequency and the turn ratio (24X) of the heating unit transformer.

[0166] A set of experiments was carried out using four samples with EN 1.4057 cores, with the heating time varying between 30 seconds and 75 seconds. After heating, the cores were removed, and the inside of the holes in the rubber cylinder was brushed with a steel brush to remove all the lost charcoal. The charcoal was collected and weighed. Based on the weights of the samples and parts before and after heating, the mass of the reacted rubber was determined as the sum of the mass of the charcoal and the mass lost as smoke and gas. The temperature sensor was placed along the core by pressing the tip of a 40 mm long syringe into the rubber next to the steel core. The temperature sensor was inserted into the tip.

[0167] A second set of experiments was carried out on samples with EN 1.4021 steel cores and with three sensors embedded in the samples: holes 5 mm deep were drilled in the middle along the steel core and the sensors were inserted. The second sensor was placed parallel to the steel rod, opposite the first sensor. Both were fixed with wire. A single winding of 3 mm thick rubber compound was wound around the core, and the last sensor was placed parallel to the other two sensors.

[0168] 1.2 Samples

[0169] Reference experiments were carried out by heating two types of bare steel cores: EN 1.4021 and EN 1.4057

[0170] The magnetic properties read from the documents cited as additional materials are:

[0171] 1. Stainless steel rod EN 1.4021QT700 - martensite, HB 220, Curie temperature 650 - 700 °C

[0172] 2. Steel rod EN 1.4057QT800 – martensite, HB 290, Curie temperature 700 - 730 °C

[0173] The range of stainless steels with permanent magnetic properties in rod form is scarce. We selected two martensitic stainless steels with different hardness, strength, and composition. The magnetic permeability of the low-carbon steel (such as ASTM A36) used in the lining substrate is generally higher than that of the high-chromium types used here.

[0174] Samples with EN-1.4057 cores: 4 samples with one temperature sensor, length 80 - 95 mm, core weight 47 - 56 g.

[0175] Samples with EN-1.4021 cores: 2 samples with three temperature sensors, length 80 - 90 mm.

[0176] In addition, unrecorded tests were conducted on two types to test the induction heating parameters.

[0177] 1.3 Results

[0178] Several heating experiments were conducted to demonstrate the delamination of steel and rubber by pyrolyzing the thin mesophase layer of the rubber. When heated to 500 °C and higher, the samples produced strong smoke and degassing in the interface layer. The exhaust gases had to be removed by strong ventilation to avoid a combustible atmosphere. In the experiment, point suction was added directly above the sample. After heating and after removing the steel core, the part of the mesophase layer that had charred into fine carbon particles was exposed and dispersed as dust. The debonding was permanent, and a secondary operation was required to remove the metal from the rubber. A large force was required to press the steel core out of the rubber before heating, and in this experiment, the steel core could be pressed out by hand after heating.

[0179] Operating temperature range: 500 °C - 550 °C, determined by TGA

[0180] TGA of the rubber determined the temperature range required for pyrolysis and the mesophase between the coked rubber and steel. The TGA results Error! Reference source not found... indicated that the rubber pyrolyzed between 300 °C and 500 °C, while the excess carbon charred burned in oxygen between 450 °C and 500 °C.

[0181] Therefore, we conclude that an operating temperature of 500 °C is sufficient, but it is beneficial to operate with a sufficient margin of 50 °C, such that the induction heating process should target an operating temperature range of 500 °C to 550 °C.

[0182] 1.4 Measurement of the reactive rubber

[0183] Four samples were heated for different times, and the amount of rubber removed as smoke and gas or carbon black was measured. The data are in the supplementary material and presented Error! Reference source not found... The important result is that induction heating is a process that can be precisely controlled. For all heating times, the steel core could be pressed out of the rubber core with slight pressure after heating. The minimum reactive layer around the steel core corresponded to 1 g of rubber or a layer thickness of 0.3 mm - 0.4 mm.

[0184] Example 2: Describe the sequence of induction heating and mechanical separation operations required to separate a steel component from a rubber matrix in a lining, the lining having a substrate and several wear-resistant steel components bonded through the rubber matrix.

[0185] 2.1 Methods and instruments

[0186] The following example relates to the sequence of operations required to separate the rubber and steel components of a composite lining. Figure 7 、 Figure 8 and Figure 9Shows the structure of a typical lining. This example involves the separation using a recycling solution consisting of a lining loading system, an induction heating system, a lining removal system, and a mechanical separation system. The lining loading and separation system includes two motorized conveyors, which are positioned with a gap (gab) of one-third of the lining length between the two conveyors. An inductor in the form of a coil connected to the induction heating system spans the entire width of the lining and is placed in the gap such that the lining can pass through the inductor or above the inductor. The two inductors are further described below. The mechanical separation system consists of a workbench with holes (whole). An electromagnetic lifting head or a switchable permanent magnet lifter is fixed below the holes. The workbench and the lifting head are either heavier than the lining or fixed in the ground and capable of withstanding a normal lifting force higher than 10,000 N. The mechanical separation system also has a crane or other lifters with grippers or magnetic lifting heads.

[0187] One inductor is a surrounding inductor through which the lining passes. The inductor can also be swept along the lining; however, this is a less preferred solution. The other inductor is flat, of the so-called "flat-plate" design. When a steel component passes through or over the inductor, it causes heating of the surface of the steel component. The heat flux of up to 1,000 kW / m 2 in the so-called surface layer of the surface is sufficient to reach a temperature of 500 °C to 550 °C within a few minutes. This time and temperature are sufficient to debond the rubber and the steel component by pyrolyzing a layer 0.1 to 5 mm thick at the rubber-steel interface. However, the rubber-steel interface is located between the substrate of the lining and the wear-resistant steel block at the top of the lining. As a result, when passing through the surrounding inductor, the substrate will shield the magnetic field at the inner surface of the top steel component, and vice versa. Therefore, the solution is to separate the metal components in two passes. The lining is placed with the substrate facing down on the conveying conveyor that passes the lining through the inductor. The inductor is placed in an intermediate position between two conveyors (the delivery conveyor and the receiving conveyor). The gap between the two conveyors must be small enough to prevent the lining from tipping over when passing through the gap. A gap of one-third of the lining length or approximately 600 mm is suitable.

[0188] The order of the two passes is:

[0189] a. In the first pass, the substrate is heated and then removed. The heating can be carried out by using the flat-plate inductor below the substrate, see Figure 6 . Alternatively, the Figure 5 surrounding inductor can also be used, but with lower efficiency because the top metal part is heated simultaneously without being heated to the temperature at which pyrolysis occurs.

[0190] After the lining has been transferred to the receiving conveyor, the lining is transferred to the station (see Figure 2) where the magnetic lifting head is fixed below the substrate, and the lifting head is an electromagnet or a switchable permanent magnet. When the magnetic field is turned on, the substrate is locked to the conveyor. Now, a crane using a hook can lift the rubber matrix and the top metal part upwards, thus separating the substrate from the rubber matrix. There may be small attachment areas after heating, and they are simply mechanically broken during the lifting process.

[0191] b. Turn off the magnetic field, and move the substrate further down the production line and remove it. The upper part of the lining descends onto the conveyor again. The inductor is changed to a surround-type inductor ( Figure 5 ) and the parts pass through the induction field in the reverse direction from the receiving conveyor to the delivery conveyor. After heating, the components are transferred back to the receiving conveyor and the magnetic fixing area. If this area is equipped with several electromagnets that can lock different components at one time, or by mechanically locking the struts of the rubber matrix, other wear-resistant steel components can be removed by the crane, and finally, for example, only two components with lifting hooks are retained. They can ultimately be removed by mechanically locking the rubber and lifting the steel components away.

[0192] Generally speaking, the mass of the target liner (see appendix) is 1240 kg, and the rubber matrix weighs 113 kg. The maximum lifting weight can be 4 x ASTM A532 segments, totaling 300 kg. The bolt fixing device in the substrate is difficult to heat, so the rubber can still be vulcanized to those after heating. A force of up to 10,000 N may be required to break this interface, so the crane and the locking device must be able to hold 1 ton.

[0193] 3.1 Methods and Instruments: Prove the superiority of using a surround-type inductor coil to debond the abrasive steel / rubber interface through electric and heat dissipation modeling.

[0194] Use COMSOL to simulate the induction heating of the actual lining, where the AC / DC module allows the combination of induction heating simulation in the steel component and heat dissipation simulation.

[0195] In addition, based on the surface heat flux calculated using COMSOL, use Solidworks Premium2022 to perform heat dissipation calculations, simulating the transfer of the heating zone along the lining - or the lining passing through or across the heating zone above the heating zone.

[0196] The purpose of the simulation is to demonstrate a reasonable inductor design and induction heating parameters that allow the steel / rubber interface to be heated to the pyrolysis temperature in a short time. In addition, to show how the control of heating power, conveyor speed, and inductor geometry allows for uniform heating of most interfaces. In addition, to prove that heating and removing the substrate first in one pass and then heating the wear-resistant steel component in a second pass is energy- and time-efficient and the best way to ensure that the component does not overheat.

[0197] Induction heating simulations were performed using a constant current of 1000 A in the coil and a power of 100 - 200 kW. The inductor was modeled as three windings extending 100 mm in the length direction of the lining and around the cross-sectional profile of the inductor. In another experiment, a nearly flat inductor with one winding was placed under the substrate. The inductor also extended 100 mm in the length direction and covered the entire width of the substrate. The shape of the inductor followed the cross-sectional shape of the substrate such that its distance to the plate was 30 mm over the entire width. It was also compared with a flat coil covering the entire substrate.

[0198] This example simulates the heating operations performed in two passes of the lining: the first pass debonds the substrate / rubber interface, and the substrate is mechanically removed after this first pass; the second pass debonds the wear-resistant steel component / rubber interface.

[0199] 3.2 Samples

[0200] Only the main steel components of the lining were considered in the calculations. The rubber matrix was excluded, and only the heat conduction between the contacting components was included in the heat dissipation calculations.

[0201] 3.3 Results

[0202] Simulation system parameters for the winding coil:

[0203] · Inductance: 10 μh

[0204] · Heat flux: 200 - 400 kW / m on the steel surface 2

[0205] · Heating power: 100 kW

[0206] · Coil power: 160 kW

[0207] · Frequency: 100 kHz

[0208] · Current: 1000 A

[0209] · Voltage: 5500 V

[0210] Heating the substrate with a flat coil covering the entire substrate or a 100 - mm - long section shows that heating the substrate at an average power of 25 kW for 20 minutes raises the temperature of the inner side (facing the rubber matrix), and the temperature rises to 500 °C. Therefore, when the power is increased, debonding of the substrate / rubber interface can be carried out in an even shorter time. For the case of completely covering the coil and for the coil covering only the 100 - mm section where the liner passes, the time, power consumption, and efficiency are equal. For the latter, the heat convection of the unheated part means a lower average temperature after heating. A challenging heating operation is heating the steel / rubber interface of the wear - resistant steel component after removing the substrate.

[0211] Heating and dissipation modeling for the second pass: The liner model is simplified to include only the wear - resistant steel component. The rubber matrix and the substrate are ignored. In Solidworks, the model is cut into 100 - mm sections along the length of the liner. The heat flux is applied to the surfaces within one section at a time. Heat conduction along the coherent steel component and convection from the surfaces exposed to air are allowed. The exposed surfaces in the heated section are modeled with a convection coefficient of 100 W / m 2 / K to simulate a strong laminar air flow along the surface. The remaining part of the exposed surface of the model is modeled with a convection coefficient of 20 W / m 2 / K to simulate a constant ventilation. The ambient temperature is fixed at 25 °C. Hereinafter, we distinguish between the outer surface and the inner surface. The outer surface is the surface exposed to air or at the edges of the model where they are covered by a thin rubber layer. The inner surface faces the rubber matrix, and their interface with the rubber matrix needs to be debonded during induction heating. A careful examination of the model shows that there are shallow and deep inner surfaces, with shallow meaning closer to the substrate than the deep surface.

[0212] Based on the results of the electro - dynamic heating simulation in COMSOL, we assign a heat flux of 300,000 W / m 2 to the external and shallow surfaces and 200,000 W / m 2 to the deep surface. Each section is heated for 150 s under these conditions. The surfaces facing the gap (gab) between the steel components are not heated. This situation simulates heating with a surround - type coil, and it observes only one metal part rather than the entire liner cross - section.

[0213] Overall, heating one section of the model for 150 s raises its surface temperature to above 450 °C. The steel component with the most complex geometry made of ASTM A532 steel is cut into five 100 - mm parts, and heating each of these for 150 s consumes 2.2 MJ of electrical energy. Therefore, continuously heating 5 parts consumes 11 MJ in 750 s, corresponding to an average power of 17 kW. After heating, the balance of all temperature differences results in an average temperature of 344 °C.

[0214] In contrast, the simulation of heating a complete unsegmented steel component only from the outer surface using a flat coil shaped to the surface profile takes 600 s to heat the inner surface to above 450 °C. When the steel passes through its Curie temperature, the upper temperature limit of the heated outer surface is 750 °C to simulate the decrease in the efficiency of inductive energy transfer. A total of 23 MJ is consumed, corresponding to an average power of 38 kW, and the equilibrium temperature is 689 °C.

[0215] The simulation shows that the efficiency of heating towards the inner surface with a wrap-around coil is twice that of heating the outer surface with a flat coil and waiting for the heat to dissipate through the structure. Equally importantly, in the latter case, the average temperature of the steel is very high. In the former case, an average temperature of 344 °C means that the steel component can be handled with a manual manipulator, while 689 °C means that automated and additional safety measures must be taken.

[0216] However, the conversion efficiency of coil power to heating power is better for the flat coil than for the wrap-around coil. Coil power is the power delivered from the induction heating power supply and is thus proportional to the consumed electrical power.

[0217] For the flat coil immediately following the outer surface of the lining, the estimated conversion efficiency is 90%. For the wrap-around coil shaped to the cross-section of the lining, the estimated conversion efficiency is 62.5%.

[0218] For the wrap-around coil, 160 kW of coil power is required to heat the inner and outer surfaces with a heat flux of 200 - 300 kW / m 2 Using the same coil power, 144 kW of heating power can be used for the case of heating the outer surface with a flat coil at 90% efficiency.

[0219] The shape of the worn lining varies from lining to lining; thus, the actual efficiency of the flat coil may easily drop below 90%. If so, the heating time from the outer surface of the lining increases.

[0220] The simulation shows that heating the entire cross-section with a wrap-around coil consumes more than 4 times the electrical energy than heating a single ASTM A532 steel component. For the flat coil, at 90% efficiency, the heating times for both cases are equal at the same coil power. However, the wrap-around coil is almost unaffected by changes in the geometry of the worn lining, while the efficiency of the flat coil is strongly affected. Therefore, for the flat coil, the actual heating time may become longer.

[0221] In summary, it has been found that comparing heating with a toroidal coil to heating the outer surface with a flat coil demonstrates these advantages: heating with a toroidal coil is at least 50% more energy efficient; the temperature is more evenly distributed at the metal / rubber interface; the temperature of the metal component is significantly reduced after heating; and for both heating models, the heating time and thus the cycle time are priory equal, but the heating time is relatively independent of the liner geometry of the toroidal coil, and for the flat coil, the greater the difference between the worn liner shape and the original shape, the more significantly the heating time may increase.

[0222] Example 4: Demonstrates the rate of pyrolysis of natural rubber and the degree of conversion achieved in the temperature range from 300 °C to 550 °C. The aim is to show that heating the metal-rubber interface to a temperature between 500 °C and 550 °C ensures complete debonding in a short time and to distinguish our method from methods of debonding at lower temperatures.

[0223] 4.1 Methods and instrumentation

[0224] TGA analysis of a piece of vulcanized rubber was carried out using a TGA / SDTA851e from Mettler-Toledo to follow the degradation during heating at a constant temperature. The aim was to determine the pyrolysis rate at temperatures in the range from 300 °C to 550 °C in a N2 atmosphere.

[0225] When natural rubber pyrolyzes, it loses up to 64% of its weight due to degassing and the loss of volatile liquids. The residue is a carbon black-like compound that burns completely in an oxygen atmosphere, as demonstrated by the TGA in Example 1. Debonding between the rubber and the steel can be obtained at a pyrolysis degree above 75%, which corresponds to the typical bonding penetration threshold. In addition, according to Example 1, it is estimated that pyrolyzing a 1 mm thick rubber layer at the rubber / steel interface is sufficient to debond the rubber from the steel.

[0226] The results were also used to demonstrate the requirements for the induction heating system and the speed at which the liner can be penetrated by the induction field. Three speeds are important for this analysis: the speed at which more than 75% of the rubber in a 1 mm thick plate is pyrolyzed; the speed at which heat dissipates from the steel surface into the rubber; and finally, the speed at which the induction system can heat the steel interface.

[0227] The TGA was carried out with the following parameters:

[0228] · Insert the sample into an oven at 200 °C and heat it to the relevant temperature within 1 minute.

[0229] · N2 gas flow rate 50 ml / min.

[0230] · In a series of experiments, the temperature was kept constant at 300 °C for 60 minutes; continued for 60 min at 350 °C; continued for 20 min at 450 °C; continued for 10 minutes at 500 °C; and continued for 10 minutes at 550 °C.

[0231] Previous standard TGA showed that up to 64% by weight of the rubber pyrolyzed into gases / volatile liquids in N2.

[0232] 4.2 Samples

[0233] Cylindrical sheets of the previously described vulcanized rubber were cut into samples with a diameter of 4 mm and a weight of 15 - 30 mg.

[0234] 4.3 Results

[0235] The weight loss of the samples within 1 minute of reaching the specified temperature was measured and compared with the maximum weight loss of 64% in the N2 atmosphere. The results can be interpreted as the fraction of the rubber sample pyrolyzed within one minute at a given temperature. The experiments showed:

[0236] 3% pyrolyzed within one minute at 300 °C;

[0237] 18% pyrolyzed within one minute at 350 °C;

[0238] 65% pyrolyzed within one minute at 450 °C;

[0239] 78% pyrolyzed within one minute at 500 °C; and

[0240] 95% pyrolyzed within one minute at 550 °C.

[0241] The maximum conversion rates at a given temperature were reached at different times:

[0242] 16% pyrolyzed within 60 minutes at 300 °C;

[0243] 60% pyrolyzed within 60 minutes at 350 °C;

[0244] 100% pyrolyzed within 18 minutes at 450 °C;

[0245] 100% pyrolyzed within 5 minutes at 500 °C; and

[0246] 100% pyrolyzed within 3 minutes at 550 °C.

[0247] It can be concluded from this study that higher temperatures are required to achieve an acceptable pyrolysis rate. Selecting a high temperature of 500 °C to 550 °C differentiates this method from methods in which pyrolysis occurs at lower temperatures of 300 °C to 350 °C. The rate of pyrolysis of the rubber interface layer at the rubber / steel interface also depends on the heat dissipation into the rubber. Using density = 8000 kg m-3; thermal conductivity = 50 W m-1 K-1; specific heat = 500 J kg-1 K-1, heat dissipates 1 mm into the rubber in 3.5 seconds. Thus, pyrolysis is a slower process in determining the rate of interfacial pyrolysis, and the temperature range of 500 °C to 550 °C allows for almost complete pyrolysis of a 1 mm layer in one minute.

[0248] If the inductor has a length of 100 mm in the long direction of the lining and the lining has a total length of 2000 mm, this means that it is possible to obtain heating of each 100 mm segment for one minute and pyrolysis of a 1 mm thick layer at the interface in 20 minutes. Even if the lining needs to pass through the induction field more times, the time for rubber-steel debonding is acceptable.

[0249] The induction heating system must be able to supply sufficient power to reach a temperature of 500 °C to 550 °C in less than one minute.

[0250] If the induction heating system is slow, it will determine the speed at which the lining can pass through the induction field.

Claims

1. A method for separating metal reinforcements from a rubber-metal composite of a used mill lining, comprising: a) By gradually passing the composite part at least once along its length or outer circumference through a high-frequency induction field, irradiating the metal parts embedded in the mill lining, wherein the induction field is driven by a power supply with an output power of 75 - 200 kW and supplies up to 1,000 kW / m to parts of the metal surface 2 , for inductively heating the metal reinforcement over the entire width of the composite material to transfer energy sufficient to pyrolyze the thin rubber layer in contact with the metal surface, thereby releasing the metal from the rubber matrix; b) Separating the metal parts of the composite material from the rubber part includes secondary mechanical separation to pull the metal parts out of the composite mill lining.

2. The method according to claim 1, including irradiating the metal parts in step a) by passing the composite part through the induction field one or more times and pulling out different metal parts from the composite mill lining after each pass.

3. The method according to claim 1, wherein the high-frequency induction field in step a) is provided by a surrounding induction coil, the shape of the surrounding induction coil follows the geometry of the cross-section of the mill lining, and optionally includes protrusions at sharp corners to reduce non-uniform heating.

4. The method according to any one of the preceding claims, optionally including, before step a), irradiating the base metal parts of the mill lining by passing the composite part along its length through a high-frequency induction field provided by a flat-type induction coil for pulling the metal substrate out of the composite mill lining before removing the embedded metal parts.

5. The method according to claim 4, wherein, the width of the coil covers the entire width of the substrate and heats the substrate from below.

6. The method according to any one of the preceding claims, wherein irradiating the metal parts embedded in the mill lining heats the metal surface to a temperature between 450 °C and 650 °C, preferably between 500 °C and 600 °C, most preferably between 500 °C and 550 °C, whereby the thin layers of primer, adhesive, and rubber on the steel surface are pyrolyzed into gases, fumes, and solid carbon-rich compounds such as coke, carbon black, and / or graphite.

7. The method according to any one of the preceding claims, the method further includes the step of controlling the rate of induction heating by: - Controlling the rate at which the composite mill lining is fed through the induction field; - Changing the power of the induction field such that different parts of the metal part are heated at different rates as it passes through the induction field; - Adjusting the geometry of the inductor coil to focus the induction field on certain parts of the metal part as the metal part passes through the induction field; - Using external magnetic materials to focus the induction field on certain parts of the metal part as the metal part passes through the induction field; - Any combination of the methods of controlling the heating rate; - To minimize the degradation of both rubber and metal to maintain the optimal performance for material recycling or metal part refurbishment.

8. The method according to any one of the preceding claims, wherein the step of separating the metal part from the rubber part involving secondary mechanical separation includes vibration, shaking, grinding, dropping, hammering, pushing, or pulling operations.

9. The method according to any one of the preceding claims, further includes classifying the rubber parts and metal parts after induction heating by: - Cutting, shredding, and filtering operations; - Gravity separation; - Magnetic separation; - Any combination of methods for sorting rubber and metal.

10. The method according to any one of the preceding claims further comprises the step of avoiding the generation of flue gas, exhaust gas and coal particles during induction heating by providing the following: - A ventilation device in the form of suction above the heating zone; - A blower, such as a fan or a centrifugal blower; - A shroud or cabinet for guiding the air flow; - A non-oxidizing air flow for displacing oxygen in the heating zone; and / or - A filtration unit for filtering particles from the discharged air or gas stream; such that the flue gas, exhaust gas and coal particles are removed from the heating zone.

11. The method according to any one of the preceding claims further comprises the step of extinguishing a fire caused by the flue gas, exhaust gas, coal particles generated during induction heating or by the rubber component itself, including a manual or semi-automatic or automatic fire extinguishing system which is above the heating zone and optionally extends partially or completely in the path of the lining, such that a fire continuously present on either side of the heating zone can still be extinguished.

12. The method according to claim 11, wherein the manual, semi-automatic or automatic fire extinguishing system comprises: - A carbon dioxide or other oxygen displacement gas fire extinguishing system; and / or - A water mist fire extinguishing system.

13. The method according to claim 1, wherein the metal component of the composite mill lining has magnetic or electrical properties.

14. The method according to claim 1 further comprises the step of controlling the penetration of magnetic flux into the composite component by using a magnetic shield, a permanent magnet or a soft magnetic material including magnetic particles such as ferrite particles around the inductor, such that it most effectively separates the rubber from the steel component.

15. An apparatus for separating metal reinforcements from a rubber-metal composite of a used mill lining, the apparatus comprises: a) An induction system, said induction system comprising a circumferential induction coil, said circumferential induction coil being shaped to follow the geometry of the cross-section of said mill lining, supplying up to 1,000 kW / m on a portion of said metal surface 2 , for induction heating said metal reinforcement over the entire width of said composite material, sufficient to pyrolyze a thin rubber layer in contact with said metal surface and effectively separate said metal component from said composite mill lining; b) An automatic conveying system for conveying the mill lining through the inductor; and c) A second mechanical separation system for separating the metal component of the composite mill lining from the rubber portion.

16. The apparatus according to claim 15, wherein, the apparatus further comprises: d) An induction heating generator capable of outputting a power of 35 to 200 kW for induction heating the metal reinforcement across the entire width of the composite material; and e) A cooling system which can cool the power supply and the inductor, having safety interlocks and differential pressure monitoring for automatic locking of the induction heating source.

17. The apparatus according to claim 15, wherein: the induction system further comprises: i) A ventilation system which includes a ventilator and a shroud, which allows an air flow of sufficient intensity to flow around the portion of the mill lining closest to the inductor to reduce the flue gas concentration below the APEX limit; ii) A magnetic shield for reducing the magnetic flux outside the induction system to zero; iii) A control unit for controlling the speed at which the mill lining component moves through the induction system; and / or iv) A focusing system which positions the mill lining component to pass it through the induction system, which is suitable for different lining geometries.

18. The apparatus according to claim 17, wherein, The ventilation system further includes a centrifugal fan that can blow gas and smoke away from the heating area to avoid ignition.

19. The apparatus according to claim 17, wherein, the ventilation system can: - Remove the generated waste gas, dust and flue gas from the heating area at a rate of 5 - 10 g / s, 10 - 25 g / s to avoid ignition; - Ensure an air exchange of 1000 - 10,000 cubic meters per hour around the mill lining part closest to the inductor; and / or - Achieve an energy transfer sufficient to raise the surface temperature of the steel component to between 500 °C and 550 °C.

20. The apparatus according to claim 15, wherein, the surrounding inductor coil of the induction system has protrusions at sharp corners to reduce non-uniform heating, and the surrounding inductor coil is shaped to follow the geometry of the cross-section of the composite lining.

21. The apparatus according to claim 15, wherein, the induction system further includes a flat-type induction coil for pulling out the metal substrate from the composite mill lining before removing the embedded metal component.

22. The apparatus according to any one of the preceding claims, wherein, the inductor includes a housing, which is in the form of a metal shield or any other form, capable of withstanding a temperature of 300 °C to 650 °C and allowing control of the magnetic flux penetrating into or out of the induction system.

23. The apparatus according to any one of the preceding claims, wherein, the inductor includes a non-metallic housing having permanent magnets, high magnetic permeability components, ferrites or other magnetic particles distributed in or around the housing to control the magnetic flux penetrating into or out of the induction system.

24. The apparatus according to claim 23, wherein, the non-magnetic housing is a high-temperature resistant thermoplastic material selected from one or more of PEEK, PSS, PSU, powder polymer, PBI, polyimide, polyamide, polyaramide or other high-temperature resistant thermoplastic materials.

25. The apparatus according to claim 23, wherein, the non-magnetic housing is a high-temperature resistant thermosetting material selected from one or more of silicone resin, modified silicone resin, epoxy thermosetting material, polyurethane or other high-temperature resistant thermosetting materials, and the high-temperature resistant thermosetting material can be cured by any means including heat, light or chemical reagents.

26. The apparatus according to claim 15, wherein, the secondary mechanical separation system includes, - A crane or grapple that can lift or shake the metal and rubber components apart after the induction heating of the metal component; - A shaking machine that can shake the metal component and the rubber component apart after the induction heating of the metal component; and / or - A vibration filter for filtering and collecting the carbon black dust and small rubber particles released from the secondary mechanical separation.

27. A mobile recycling unit comprising the apparatus according to any one of claims 15 to 26, the apparatus being housed in one or more containers and capable of being delivered to the required location.

28. The mobile recycling unit according to claim 27, Wherein, the unit can operate when partially or fully installed in the packing case.

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