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Processing Recycled Foam

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Schematic of Dart's Polystyrene Recycling Facility, Mason, MI Receiving and Sorting Conveying Grinding Washing Drying Storing Mixing Extruding Pelletizing and Drying Packaging Shipping
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1. Receiving and Sorting

Truckload of used polystyrene foam
Employee sorting polystyrene foam

Post consumer expandable polystyrene is shipped to one of our four recycling facilities in clear bags and manually unloaded.

Before the foam can be recycled, it must be inspected for any contaminants, such as paper, metals, and food wastes.

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2. Conveying

Polystyrene foam moving on a conveyor

Once sorted, conveyors move the inspected foam up an incline. At the end of the inclined conveyor, the foam drops into the grinder.

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3. Grinding

Polystyrene foam in grinder

Grinders process the foam into "fluff".

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4. Washing

This proprietary process is used only for contaminated material. Typically, the fluff moves directly from the grinder to the silos thus passing this operation.

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5. Drying

This proprietary process is used only for contaminated material that required washing. Typically, the fluff moves directly from the grinder to the silos thus passing this operation.

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6. Storing

Temporary Storage Silos

The fluff is held in temporary storage silos before extrusion. Storing fluff in silos assures a continuous supply to the extruder.

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7. Mixing

Combination of Silo Feeds

The mixer combines the separate silo feeds into one.

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8. Extruding

Extrusion machines

Heat and friction change the fluff from a solid into a melt. This process removes all of the air trapped in the melt. The melt exits the extruder as strands of polystyrene.

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9. Pelletizing & Drying

Polystyrene pellets cooling in water
Drying machine

As water cools the strands of polystyrene, a high speed blade cuts them into pellets. Process water is then filtered and reused throughout this process.

Water and pellets enter the bottom of the dryer. A screw, spinning at high speed, moves the slurry up through the unit. Centrifugal force pulls the water away from the pellets. Dry pellets exit near the top.

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10. Packaging

Polystyrene Pellets being sorted
Boxing of polystyrene pellets

Once dried, pellets are sorted by size and boxed by color.

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11. Shipping

Truck ready to ship polystyrene pellets

Boxed, recycled polystyrene is then sent to various manufacturers to be made into many durable consumer goods. Some of the products manufactured from recycled polystyrene include rulers, video cassette shells, toys, sun visors, and building insulation. Additional items include flower pots, egg cartons, push pins, landscape supplies, and desktop accessories, to name a few.

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Receiving and Sorting Conveying Grinding Washing Drying Storing Mixing Extruding Pelletizing and Drying Packaging Shipping