Shredding operation

Shredding operations may also include apphances (white goods) which are being recycled in increasing quantities at least partiy because of the banning of apphances from landfills in many states. The recycling rate for apphances in 1994 was 70% compared to 62% in 1993 when 1.4 million t of ferrous scrap was recovered from 36 million apphances. The recycling rate was 55% in 1992 (10,11). 

Kutrieb Corporation (Chetek, Wisconsin) operates a pyrolator process for converting tires into oil, pyrolytic filler, gas, and steel. Nu-Tech (Bensenvike, Illinois) employs the Pyro-Matic resource recovery system for tire pyrolysis, which consists of a shredding operation, storage hopper, char-coUection chambers, furnace box with a 61-cm reactor chamber, material-feed conveyor, control-feed inlet, and oil collection system. It is rated to produce 272.5 L oil and 363 kg carbon black from 907 kg of shredded tires. TecSon Corporation (Janesville, Wisconsin) has a Pyro-Mass recovery system that pyroly2es chopped tire particles into char, oil, and gas. The system can process up to 1000 kg/h and produce 1.25 MW/h (16). 

Burning tires whole obviates the need for expensive shredding operations. However, the burning of whole tires requires a relatively sophisticated high temperature combustion facility to keep emissions within environmental limits. It also requires equipment capable of handling the whole tires and feeding them into the combustion chamber. 

Most of the plants currently burning tires for fuel do not have the capability to burn whole tires. Instead they must burn tires that have been shredded into chunks. In this form it is known as tire-derived fuel (tdf). The size of the pieces can vary from 2 inches to 6 inches, depending on the shredding operation. Typically,... 

Cost is another concern associated with the use of recycled carpet waste fibers in concrete. Currently a vast amount of carpet waste is disposed of each year and therefore the cost of raw material for the recycled fibers is negligible. The disassemble process to convert the waste into fibers suitable for concrete reinforcement requires only simple, inexpensive shredding operation. Therefore the cost of the recycled fibers will remain very competitive with virgin fibers for FRC. 

A bar turbine that produces high shear for dispersing and shredding operations similar in use to flie R-500, bars are mounted on a disc with alternate blade on top and bottom of disc... 

ENSCO (El Dorado, AK), like Rollins, combines a rotary kiln with liquid injection incineration. However, the shredder-kiln is totally enclosed. Thus, no PCB can escape during the shredding operation. 

Processing costs for a tire shredding operation will vary depending upon many factors, such as feed material, throughput, system being used (portable vs stationary) site conditions, preventative maintenance program, disposal options, power available and local markets, desired end product, geographic location. 

In 1985, the Emanuel Tire Company in Baltimore processed more than 3 x 10 tires into chips, which are mostly sold to pulp and paper mills as a supplemental fuel the remainder is sold to reclaiming facHities or landfiUed. Only 20% of passenger tires are suitable for recapping. Nonrecappable tires are shredded into 5-cm chips. The Emanuel Tire operation is capable of reducing the 5-cm chips to smaller sizes. Shredded waste tire chips can be granulated into very fine wire and fabric-free mbber particles. 

In the wood rosin process, rosin is isolated from aged pine stumps that have been left in fields cleared for farming or lumbering operations. The stumps are cut and shredded to pieces the size of matchsticks. The wood chips are then extracted with an appropriate solvent, eg, aUphatic or aromatic petroleum hydrocarbons or ketones. The extract is fractionally separated into nonvolatile cmde rosin, volatile extractibles, and recovered solvent. The dark rosin is usually refined further to lighter-colored products using selective solvents or absorption. 

Cementation. Cementation is the precipitation of copper from copper leach solutions by replacement with iron. It was formerly the most commonly used method of recovering copper from leach solutions but has been replaced by solvent extraction—electro winning. The type of iron used ia cementation is important, and the most widely used material is detinned, light-gauge, shredded scrap iron. This operation can be performed by the scrap iron cone (Keimecott Precipitation Cone) or a vibrating cementation mill that combines high copper precipitation efficiency and reduced iron consumption (41). 

Size of material shredded Wastes to he digested should he shredded to a size that will uot interfere with the efficient fuuctioniug of piimpiug aud mixiug operations. 

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