TECHNICAL LIBRARY

 

New Tire Recycling System Lowers Costs, and Relies on Chemical-Free Freezing

Regal Recycling, Jamaica, NY, is using a new system to recycle tires. Designated Crumb Rubber Technology, the system uses an air-based cryogenic system for freezing rubber at -120 degrees Celsius rather than relying on nitrogen, ammonia or freon for reaching cryogenic freezing. But before this step, whole tires are shredded to 2" x 2" (51 mm x 51 mm) chips. A screw conveyor brings the chips into a freezing chamber. Then a hammermill pulverizes the brittle chips into granulated rubber, steel and fiber. During phase 4, the materials are classified by product and size. The three byproducts are steel, fiber, and crumb rubber in particle sizes from 381 to 864 microns.

The crumb rubber is classified using a Kason VIBROSCREEN circular screen separator equipped with 20 mesh and 40 mesh screens. A Kleen Screen ring assembly prevents rubber particles from blinding the screen. The vibrations imparted from the gyrator motor impact the plastic rings which in turn impact the bottom of the screen to dislodge any rubber particles that could block a screen opening.

The 40" (1020 mm) diameter circular screen separator operates night and day, helping Regal Recycling process 4,200 tires per day, 25 days per month. With its heavy duty , oversize bearings, the VIBROSCREEN is well suited for round the-clock duty when downtime is to be avoided at all costs.

The economics of this process are thought provoking regarding the viability of recycling. Tipping fees (a charge paid by the person bringing the tire to the processing facility) are 50 cents per tire so for 1.26 million tires per year, the fee is $630,000. Approximately, $3,528,000 income accrues from selling the rubber (about 70% of each tire is rubber by weight). The steel which accounts for about 25% of each tire by weight, is worth about $189,000 annually.

Unlike earlier tire re-processing operations, the Crumb Rubber Technology system requires only 1.5 kw per tire, far lower than conventional systems. The VIBROSCREEN unit is one of the most efficient circular screen separators on the market, contributing to the system's minimal power needs.

Clearly, there's substantial profit in recycling. The reprocessed rubber serves as stock for floor mats, rubber bumpers at loading docks and harbors, mud flaps, and tires for construction vehicles and forklifts. Buyers from allover the world take advantage of this cost effective resource. The cotton fibers serve as filler for upholstery and could be used for rope too.

Aside from fitting nicely into market driven economies, the recycling operation prevents tires from piling up, leaving land available for better purposes. According to the Rubber Manufacturers Association, Inc., roughly 214.5 million tires were sold for use on passenger cars alone in the u.s. in 1991. Though many tires are re-used for retreads, countless acres are covered by decaying tires. With Regal Recycling's new process, there's finally a viable and profitable alternative to placing used tires in landfills.

The crumb rubber is classified using a Kason VIBROSCREEN circular screen separator equipped with 20 mesh and 40 mesh screens.