Author
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Anthony, William |
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Submitted to: Scrap Tire News
Publication Type: Trade Journal Publication Acceptance Date: 7/14/2005 Publication Date: 8/1/2005 Citation: Anthony, W.S. 2005. Increasing profits in crumb rubber plants. Scrap Tire News. Vol. 19(8): 12-19. Interpretive Summary: Over 285 million tires are discarded annually in the U. S. and between 1 and 3 billion are currently in landfills. About 75% of the discarded tires are placed in landfills annually, and although they represent only 1% of the municipal solid waste, they are not biodegradable and pose a significant environmental problem. The scrap tire recycling industry in the United States has grown rapidly since 1986. One of the more acceptable disposal practices which is estimated to use 18 million tires per year, the tires are cut into pieces and "pulverized" into rubber particulates and polyester/nylon fiber using either a cryogenic treatment (freezing to 300 °F with liquid nitrogen) and hammer mill or by ambient grinding. Unfortunately, from 10 to 50% of the tire is still discarded as waste called fluff. A new machine to separate the waste fluff produced by tire recycling plants into marketable products such as crumb rubber and fiber was developed and tested in laboratory and field recycling facilities. The new machine divided the fluff into 70% crumb, 13% clean fiber, 9% partially cleaned fiber, 5% large pieces of unground rubber, and 3% waste. Economic evaluation for three tire recycling plants that processed from 2 to 5 million tires annually indicated that their gross income could be increased nearly $2 million per year depending on the quantity of tires processed and the landfill costs. The machines cost about $100,000 and are now available for commercial use. Technical Abstract: Economic evaluation of new fluff processing machines for three tire recycling plants that processed from 2 to 5 million tires annually indicated that gross income could be increased from $672,000 to $1.935 million per year depending on the quantity of tires processed, market value of the crumb, and the landfill savings. The machines process about 1,000 lbs/hr/ft and cost about $100,000. The machines are now available for commercial use. Laboratory research as well as field tests at a commercial tire recycling facility demonstrated the viability and economic value of the new machines to separate the waste fluff produced by tire recycling plants into marketable products such as crumb rubber and fiber. Fluff sampled at 20 crumb plants contained 34 to 87% crumb by weight, and from 1 to 26% fiber. About 65% of the fluff was retrieved as crumb, which was mostly 300 microns or smaller. Field tests at a commercial tire recycling facility yielded 70% crumb, 13% clean fiber, 9% partially cleaned fiber, 5% large pieces of unground rubber, and 3% cyclone waste. The crumb contained 0.2% fiber and was mostly 300 microns or smaller. Fluff from five recycling plants was tested on a commercially manufactured version of the machines and produced 40 to 67% crumb, mostly 300 microns or smaller. Markets already exist for crumb and many potential markets exist for the recovered fiber. |
