Cryogenic Grinding in Tire Recycling

The escalating environmental challenges posed by waste rubber tyres (WRTs) necessitate innovative solutions to address their detrimental effects on the geoenvironment. Thus, knowledge about recent advancements in material recovery from WRTs, emphasising utilisation within framework of United Nations Sustainable Development Goals (SDGs) and circular economy principles, is need hour. Keeping this mind, various techniques generally used for recovery, viz., ambient, cryogenic, waterjet, so on, which unveil approaches reclaiming valuable resources (viz., recycled rubber, textiles, steel wires, etc.) WRTs devulcanisation physical, chemical, microbial) are elaborated paper. In parallel, paper explores recovered materials, highlighting application geotechnical geoenvironmental engineering development projects while addressing necessary precautions associated risks/concerns. This incorporates principles into focuses achieving SDGs promoting resource efficiency minimising impact.

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A pollution-free method for recycling tires that involves cryogenic freezing, crushing, and sieving instead of shredding and high-temperature treatment. The method involves shredding tires, spraying them with water, filtering, drying, freezing, crushing, separating metal fibers, crushing again, sieving, and screening to produce clean tire particles. The cryogenic freezing step reduces odor, dust, and pollution compared to high-temperature processing.

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Pollution-free tire recycling method using cryogenic freezing to recycle tires without generating high pollution levels. The process involves shredding tires, spraying them with water, blow-drying, freezing to -150 to -300°C, crushing, separating metal fibers, further crushing, cyclone separating, and screening to produce fine tire particles. This cryogenic recycling reduces odor, dust, and pollution compared to high-heat recycling.

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A waste tire recycling system that pulverizes tires into rubber powder without pollution. The system involves a series of crushing, washing, freezing, and grinding steps. The tire is first crushed into fragments. The fragments are washed and then crushed again to make smaller fragments. These fragments are then frozen and ground into primary powder. The primary powder is split and further frozen and ground into secondary powder. This multi-stage freezing and grinding process allows efficient pulverization of tires into rubber powder without generating pollutants like dioxins.

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A cold energy recovery system for recycling waste tires and plastics into powder using liquid nitrogen. The system has a material tank with chambers, a feeding pipe, a liquid nitrogen chamber, a powder tank, and pipes connecting them. Nitrogen from the liquid nitrogen chamber is pumped into the feeding pipe to cool the material. The cooled material goes to the liquid nitrogen chamber for further cooling. Nitrogen from there is pumped into the feeding pipe to cool more material. The powder produced in the liquid nitrogen chamber is pumped to the powder tank. This recycles and reuses the nitrogen's cold energy to reduce waste. The chambers, pipes, and tanks are insulated to further minimize cold energy loss.

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A device for crushing old tires using refrigerated airflow that freezes and crushes tires in a uniform and efficient manner. The device has a crushing chamber, pre-cooling chamber, and heat exchange chamber. The crushing chamber has a rotating shaft with connecting rods and a top plate for tire crushing. The pre-cooling chamber has a refrigerator and the heat exchange chamber has an exhaust pipe. Air compressor cools and pressurizes air, which is sprayed downward by the first branch pipe and upward by the second branch pipe to freeze the tires. The reversing airflow and high pressure crush the frozen tires. The uniform freezing prevents uneven crushing. The heat exchange recovers refrigerant energy.

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A method to produce high-quality rubber powder from waste tires for use in tire treads. The method involves cryogenic grinding of the tire rubber at sub-glass transition temperatures to achieve small particle sizes. It uses a two-stage nitrogen cooling process with normal and low temperatures. This produces a high proportion of fine rubber powder with improved properties for tire treads compared to conventional grinding. The cryogenic grinding prevents heat buildup and stickiness, allowing finer sizes. The resulting powder can be used in tire treads for better performance and sustainability.

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Device to prepare fine rubber particles from waste tires that avoids the limitations of existing methods. The device uses a vibratory feeder to drop the crushed tire blocks into a pre-cooling chamber where they jump and tumble. This motion further breaks the rubber as it rolls down and exits through a chute. The chamber is cooled by a freezer to solidify the rubber. The freezing chamber has an air inlet and outlet to circulate cold air. The vibratory feeder and tumbling motion in the pre-cooling chamber improve particle size reduction compared to just freezing the rubber.

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Low-temperature grinding equipment for recycling waste tires into fine rubber particles. The equipment uses a closed-loop cooling system with liquid nitrogen to precool and then cool the tire rubber before grinding. A low-temperature crushing device with adjustable pressure applies force between grinding discs at low temperatures to prevent carbonization and oxidation. The equipment has a feeder, cooling boxes, and a controller to optimize grinding parameters for customized particle size.

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A production line and method for preparing high-precision rubber powder from waste rubber that enables efficient and scalable production of ultra-fine rubber powder for applications like thermoplastic elastomers. The method involves a combination of normal temperature grinding and freezing grinding to brittleize the rubber. The production line includes stages like crushing, granulation, milling, and freezing grinding. The freezing grinding is performed below the rubber embrittlement temperature using separate cryogenic subsystems. This allows the rubber to be frozen and brittle enough for fine grinding. The line also includes steps like metal separation, fiber removal, and drying.

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Multi-stage rubber powder crushing method and device that enables efficient recycling of rubber waste by crushing and grinding it into powder. The method involves using multiple stages of crushing devices with progressively finer screens to reduce the rubber particle size. The crushing sequence starts with a rough processing mechanism, then a semi-finishing device, followed by a freezing stage to cool the rubber below its glass transition temperature. The frozen rubber is then ground to a powder in a finishing mechanism. The powder is further ground and screened to separate out oversized pieces. This multi-stage process allows effective recycling of rubber by breaking it down into small particles suitable for reuse.

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A recycling system for waste tires from electric vehicles that uses cutting, cooling, crushing, screening, and sorting steps to convert the tires into usable rubber powder. The system involves a cutting device with transverse and longitudinal blades to shape the tires. Then, the tires are rapidly cooled using liquid nitrogen to make them brittle. The cooled pieces are crushed, ground, and screened to separate the rubber powder from impurities.

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Producing micronized powders like rubber powder from heterogeneous materials like used tires in a predictable particle size range and concentration that allows incorporation into other applications regardless of the infeed material. The method involves cryogenic grinding, screening, warming, fiber and metal removal, and accumulation steps. Warming the particles using a PID loop with recirculation to improve efficiency. A vibrating screener removes fibers while letting the micronized powder pass. Accumulation decouples grinding and screening rates.

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Rubber powder production device for recycling waste tires that improves quality, efficiency and reduces costs compared to room temperature crushing. The device uses low temperature crushing stages to prevent rubber degradation. It has conveyors, crushers, screens and a particle recovery system. The first crusher is below the feed conveyor, the second crusher is above the discharge conveyor, and the screens are between. This allows multiple crushing stages at lower temperatures. The particle recovery system captures fines from the screens to recycle them. The low temperature crushing prevents rubber degradation and improves powder quality. The multi-stage crushing and screening allows flexible particle size control.

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Low temperature processing of rubber powder to produce fine powder from waste tires at low energy consumption. The method involves freezing the 60-120 mesh rubber powder at very low temperatures (-60 to -10°C) in a vacuum chamber for 3-5 minutes. The frozen powder is then crushed into the desired size using a rubber crusher in the same low temperature environment. This allows efficient and energy-saving production of fine rubber powder from waste tires.

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A low-cost, low-power, and efficient method to process scrap tire rubber into a modified powder. The method involves freezing the scrap tire rubber at -180°C for 24 hours, then pulverizing it into powder using a cryogenic grinder at -180°C. This freezing and pulverization process improves the performance of the powder compared to room temperature pulverization alone. The frozen rubber is easier to fracture into smaller particles, resulting in a powder with better properties for rubber products.

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A recycling process for waste tires that cools and grinds the rubber into powder without incineration. The process involves cutting, grinding, separating impurities, screening, cooling, and cleaning the rubber particles. It uses machines like crushers, screens, cyclones, separators, shakers, and mills. The rubber is pre-cut, then quenched and ground into smaller pieces. Impurities are separated and classified. The rubber is cooled by grinding in liquid nitrogen mills. Powder screening removes fibers and dust. This produces uniform, cooled rubber powder for reuse. The process avoids incineration emissions.

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A system for recycling waste tires into powder using liquid nitrogen to break them down without burning or polluting. The system involves crushing the tires, cooling them with liquid nitrogen, and then grinding them into powder. The liquid nitrogen cooling helps make the rubber brittle for easier grinding into powder. The cooled rubber is then purified to remove impurities before final grinding. This allows clean, recyclable rubber powder to be produced from waste tires without incineration or other pollution.

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A segmented cryogenic comminution system for efficiently and cost-effectively pulverizing waste rubber into powder without using expensive liquefied gases like nitrogen. The system uses a two-stage crushing process with temperature control between stages. The first stage crusher breaks the rubber into scraps while a water cooling device lowers the temperature below a critical point. This prevents softening during the second stage crushing. The cooled scraps are then fed to the second stage crusher for final pulverization. By controlling the temperature, the system eliminates the need for large volumes of expensive liquefied gases like nitrogen to absorb heat during crushing.

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A scrap tire production system using liquid nitrogen to crush tires into high purity powder without pollution. The system involves a multi-step process including crushing, cooling, purification, and milling. Tires are crushed twice with screens to remove impurities. They are then cooled with liquid nitrogen to brittleness. Further purification stages separate impurities. Finally, the nitrogen-cooled particles are milled into powder. The liquid nitrogen cooling prevents pollution during crushing. It also allows efficient granulation and milling. The purification stages ensure high quality powder.

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A grinding machine for recycling waste tires into fine powder. The machine has separate grinding drums that rotate in opposite directions to crush the tires. This allows separation of the iron core from the rubber. The drums have cooling spaces with laminated blades to efficiently grind the tires. The blades have teeth on the outer surface and hexagonal shapes on the inner surface. This design prevents the ground rubber from sticking to the blades. The separated iron cores and ground rubber are discharged separately.

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A cold grinding process for recycling waste tires into high purity rubber powder using a specialized machine setup. The process involves cooling the waste tire rubber granules to -68°C in a nitrogen-cooled grinder. This reduces the grinding temperature to optimize grinding efficiency and particle size control. The cooled rubber is then ground into fine powder using a reverse-type grinding machine. The powder is further screened to separate out high purity rubber particles. This allows efficient recovery of high quality rubber powder from waste tires.

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Cryogenic processing of rubber waste to produce high-quality devulcanized rubber powder that can replace fresh rubber in manufacturing. The method involves cooling the rubber waste to very low temperatures using liquid nitrogen or cold air. This makes the rubber brittle and enables it to be cryogenically milled into small, irregularly shaped particles with active surfaces. This devulcanized cryogenic rubber powder has properties similar to fresh rubber and can replace it in production at a much higher rate, improving quality compared to smooth-surfaced cryogenic rubber powder made by grinding.

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High-efficiency low-temperature grinding method for preparing micro powder rubber from waste tires. The method uses a low-temperature crushing system with liquid nitrogen refrigeration. This allows direct solidification and grinding of the rubber at very low temperatures to achieve fine particle sizes. The low temperature prevents material melting and sticking in the grinding equipment. The liquid nitrogen also helps with material flow and reduces energy consumption compared to traditional grinding methods. The low-temperature grinding system has a hopper for solidified rubber feeding, a crushing chamber cooled by liquid nitrogen, and a collection vessel for the micro powder.

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A process to comminute used rubber tire particles into a fine powder that can be used in the manufacture of new tires without needing functionalization or surface activation treatments. The process involves grinding the tire particles in a cryogenic mill at low temperatures to create free radicals that vulcanize rapidly when mixed with fresh rubber. The cryogenic grinding also reduces particle size and controls distribution. This results in a powder rubber with improved properties and compatibility compared to unprocessed tire crumb.

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A method for recycling waste rubber from tire manufacturing into new tire raw material using nitrogen gas. The waste rubber is crushed at low temperature using liquefied nitrogen. The crushed rubber is then used as a recycled raw material for tire production. The vaporized nitrogen gas generated during crushing is captured and supplied to the tire vulcanization process as a pressure medium. This allows recycling the waste rubber without energy-intensive reprocessing and reduces carbon emissions compared to thermal reprocessing.

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A process for recycling tires that involves washing the rims, cutting them into pieces, cryogenically freezing the pieces, grinding them, separating the nylon and polyester fibers, screening the rubber for size, compressing the steel, packing the nylon/polyester, and packing the rubber. This allows high recovery of usable materials from tires compared to traditional abrasive grinding. The cryogenic freezing step enables efficient separation of rubber from steel and fibers without clogging issues.

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A method and apparatus for producing crushed and powder rubber from used tires and other rubber products with a predetermined particle size range. The process involves cooling the rubber particles with a cryogenic fluid like liquid nitrogen to a specific temperature, then grinding them to the desired size. The cooling step reduces particle bonding and enables efficient grinding into consistent sizes. This allows producing rubber powder and crumb with targeted particle sizes suitable for tire and other rubber product manufacturing.

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Efficiently producing powder rubber from recycled tires and other used rubber sources in a way that enables cost-effective, large-scale production of powder rubber with consistent particle size ranges for use in new rubber products. The process involves preprocessing the rubber particles to specific size ranges, drying them, precooling them to -0°F, freezing them below their glass transition temperature with cryogenic liquid, and then controlled comminution that varies based on the original particle size. This allows consistent, predictable powder rubber with targeted particle sizes for incorporation into new rubber products.

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A method and equipment for recycling discarded rubber products like tires to extract and reuse the components like steel, textile, and rubber without degradation. The method involves separating the tires into beads, sidewalls, and treads using water jets. The sidewalls and treads are then cut into uniform pieces. The cut pieces are frozen and crushed to separate into rubber granulate, metal, and textile. The mixture settles and is sorted into fractions. This allows complete separation and recovery of the individual components without degradation. The freezing chamber has a controlled liquid nitrogen level using sensors in an interconnected chamber to maintain proper freezing conditions. The crushing knives have shaped edges like spirals or circles.

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A waste rubber recycling system for converting used rubber products into reusable fine rubber powder. The system uses a specialized breaking machine with parallel drums and an adhesive lining to crush and grind the waste rubber into smaller particles. The process involves pre-smashing the rubber in the breaker, removing impurities like fibers and steel, then grinding it to the desired particle size. This allows separation and recycling of the waste rubber instead of landfilling.

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A process to convert old tires into powdered rubber that can be used in various applications. The process involves chopping the tires into pieces, then cooling them at low temperatures to make the rubber brittle. This allows further grinding into powder. By cooling the chopped pieces before further processing, it prevents melting and enables smaller granule sizes. The cooling step enables converting tires into powder, which cannot be achieved by just chopping.

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A process for cryogenically grinding scrap rubber into powder suitable for recycling applications. The process involves cooling scrap rubber chips to temperatures around -90 to -110°C using a nitrogen-filled cryogenic cooling tank. The cooled rubber is then comminuted into powder smaller than 10 mesh size using mechanical grinding equipment. Cryogenic grinding allows the rubber to be easily pulverized into a finer particle size compared to room temperature grinding. The low temperature brittleness of the rubber makes it easier to grind into powder.

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Method for separating the rubber and non-rubber components of waste tires in an efficient and cost-effective way by freezing the tires first. The frozen tires are then crushed to separate the rubber from the non-rubber parts like carcass, belt, and bead wire. This allows easy recycling of the rubber and non-rubber materials separately. The freezing step makes the rubber brittle and easier to crush while keeping the non-rubber components intact.

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A cryogenic system for processing scrap tires and other rubber waste into usable secondary raw materials. The system uses multiple stages of cryogenic cooling and crushing to break down the rubber waste into granules and powder. The cold processing allows brittleization and separation of the rubber from textile and metal reinforcements. The cryogenic steps include pre-shredding, cryogenic crushing, classifying, and sorting. The frozen rubber granules and powder can then be further processed into new tire components without strength or resilience loss. The cryogenic steps enable efficient separation and recycling of rubber waste.

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Efficiently recycling waste tires by pulverizing them into sections, cooling them to ultra-low temperatures in liquid nitrogen, then crushing and magnetically sorting the sections to separate the rubber particles from the steel components. This allows recovering usable rubber and recycling the steel. The large sectioning step before cooling prevents the need for expensive crushing equipment. The ultra-low temperature makes the rubber brittle and easier to crush. The sections are then further crushed and magnetically sorted to extract the rubber particles.

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A process to efficiently crush waste tires into small rubber particles using a two-stage crushing system. The process involves cutting, cleaning, and crushing the tire strips to produce micro-sized rubber powder. The first stage involves using a round machine to cut the tire strips into slivers. This is followed by cleaning, thickening, and initial crushing to reduce the slivers to smaller pieces. In the second stage, further crushing and sieving steps are used to grind the rubber into micro powder. The process involves multiple stages of cutting, cleaning, thickening, and crushing to efficiently convert tire waste into micro rubber particles.

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A method for producing ultra-fine powder from waste resources like tires using cryogenic pulverization. The method involves supplying waste resource powder into a grinding stator, injecting liquefied gas to cool the powder to a cryogenic state, and then pulverizing it using a rotor while pressed and rotated. This allows efficient pulverization of waste resources like tires into ultra-fine powder at cryogenic temperatures using minimal liquefied gas.

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A method for efficiently and automatically recycling waste tires, waste synthetic resins, and waste nets into reusable powdered form. The recycling process involves cutting the waste into smaller pieces, finely crushing it, vibrating the crushed material to separate large pieces, freezing the fine particles, grinding them into powder, drying the powder, classifying by specific gravity, further classifying by magnetic properties, and finally packing the powdered recycled material.

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An apparatus for recycling waste rubber and waste synthetic resin into a powder form for reuse. The recycling process involves freezing the waste material inside a cylindrical silo using a high-pressure cooler, stirring the frozen material with an impeller, then discharging it through a rotary valve to a pulverizing device. The pulverizing device finely grinds the frozen waste into powder. The silo is insulated to prevent heat loss during freezing. The frozen material is easier to pulverize into a powder than unfrozen material. The recycled powder can then be used as a substitute for virgin resin in molding applications.

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A method for preparing rubber powder from waste tires that avoids the energy-intensive liquid nitrogen freezing process. The method involves crushing the tires into coarse rubber particles, then cooling them with compressed air that's been refrigerated and expanded. This lowers the rubber's temperature below the glass transition to make it brittle, which allows further grinding into powder. The compressed air cooling is achieved using a fluidized bed cooler where cold air reversely merges with the tire particles as they fall. The key is using compressed air refrigeration rather than liquid nitrogen.

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A process and apparatus for making crumb rubber from used tires that involves multiple cryogenic cooling and comminution steps to produce fine crumb rubber. The process starts by shredding tires into rubber particles containing metal and fiber. The particles are cooled in a cryogenic liquid. Then they're further comminuted to remove metal and fiber. Finally, they're cryogenically cooled again and comminuted further to make the crumb rubber. The cryogenic liquid is recycled between steps to minimize fluid usage. This allows efficient comminution and particle size reduction without excessive cryogenic fluid consumption.

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Low-temperature mechanical recycling of waste tires, rubber, plastics using cryogenic cooling. The process involves cooling the waste material to very low temperatures (-150°C) using liquid nitrogen. This makes the material brittle and allows it to be mechanically shredded and crushed. The low temperature prevents combustion and allows safe mechanical processing. The frozen material can be further processed into usable forms like granulated rubber, recyclable powders, and metal reinforcements. The cryogenic recycling avoids pyrolysis issues like expensive plants, polluting fumes, and low component recovery.

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Economical and environmentally friendly process for recycling used tires into usable materials. The process involves a low-temperature comminution system that efficiently separates the tread, sidewall, and bead portions of tires. The system uses a cutting blade to make an initial transverse cut through the tread, followed by a rotating spindle with radially-inward cutting blades to separate the tire sections. This allows recovery of the rubber compounds from each part for reuse in various applications. The low-temperature comminution prevents thermal degradation of the rubber. The system is portable and economically feasible for smaller volumes of tires compared to large-scale tire shredding.

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A simple and efficient method for granulating solid materials like old tires using cryogenic liquids instead of expensive peeling machines. The method involves cooling the solid material to a low temperature using cryogenic liquid like liquid nitrogen, then breaking it into granules using a conveyor system. The cryogenic liquid is pushed into an insulated receptacle above the solid material using compressed gas. The solid material is loaded into the receptacle and vented to the atmosphere, then the lid is closed and compressed gas is introduced into the cryogenic reservoir below. This forces the liquid into the receptacle and cools the solid material. The liquid is then drained and the solid granulated. The insulated receptacle and reservoir prevent heat transfer.

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A process for recycling worn or damaged tires without sorting them first. The process involves roughly tearing apart the tires, freezing the torn pieces, crushing the frozen material, separating out the metal, grinding the metal-free fraction, and then combining the metal-free and metal fractions for regeneration. This allows recycling of the entire tire, including metal, without sorting, while minimizing loss of rubber and reducing the amount of freezing agents needed compared to prior methods.

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Process for producing reusable rubber from discarded fiber-reinforced rubber articles like tires by cooling, flexing, crushing, and separating the cooled material to disunite the rubber component from the fiber component. The cooled rubber becomes brittle below -40°C and can be comminuted with the fiber separated by mechanical or cyclonic methods. The extent of fiber retention in the reusable rubber can be adjusted based on desired application needs.

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