Reclaimed materials

Although more often associated with household and commercial waste, recycling has proven to be very successhil in the industrial arena. Industrial recycling is the recovery for reuse or sale of materials from what otherwise would be wastes destined for disposal (5). Typically, the reclaimable materials employed in industrial recycling may consist of obsolete products, spent materials, industrial by-products or residues, or pollution control products. The recycling of many of these products is so well estabHshed that under standard commercial practices such materials are destined only for recovery, not for disposal. 

Tires, natural mbber tubes, and butyl tubes are the main sources of scrap and reclaim (see Elastomers, synthetic-polyisoprene). Specialty reclaim materials are made from scrap siUcone, chloroprene (CR), nitrile— butadiene (NBR), and ethylene—propjlene—diene—terpolymer (EPDM) mbber scraps (see... 

Recycling using, reusing, or reclaiming materials/waste, including processes that regenerate a material or recover a usable product from it. 

The aromatic polyols resulting from the reaction can be mixed with commercial polyols, blowing agents, surfactants, catalysts, and polymeric isocyanates to produce a rigid polyurethane foam. n compared w control foams produced from commercially available polyester polyols, the foams produced from reclaimed materials were found to have essentially the same properties. 

Reclaimed material may comprise a portion of the linear low density polyethylene. 

Blends of PC with ABS or ABS/HIPS can be prepared by direct mixing for the reclaimed materials, i.e., blending without the need of sorting before. It has been demonstrated that these mixtures can be easily processed. Furthermore, the mixtures show acceptable mechanical properties (40). 

Excess product from the packaging operation is continuously remelted in a rework SSHE in a controlled manner and returned to the system via the balance tank or a positive pump facility for adding reclaimed material. 

Considerable effort has been directed to solving this problem. Although chemical probes have been developed that selectively cleave carbon-sulfur and sulfur-sulfur bonds but not carbon-carbon bonds, most of the effort on devulcanization processes has been focused on providing a usable form of rubber suitable for use as a reclaimed material in new articles. ... 

Cellulose content varies. Virgin fibers produced Irom wood pulp contain 99.6% cellulose and are white. Fibers manufactured from reclaimed materials contain 75% and are gray or brown. Cellulose fibers (especially virgin materials) have a complex morphological structure which facilitates reinforcement (Figure 2.80). 

A further prerequisite for an increase in direct recycling is the necessity for the consumer to learn to deal with reclaimed materials, which require modified production conditions. 

True recycling on a global basis demands that some part of the total polymer market input stream be replaced by reclaimed material. This, in turn, requires a purification of contaminated waste polymer to a state that allows it to replace material in the same application or, at least, to replace the polymer in another existing application currently using virgin material. 

Funding is a particularly sensitive issue. All of the world s facilities that reclaim materials from Ni-Cd batteries at present are being paid to do so. That is, because of low metal prices, reclamation - even where the reclaimer has no responsibility for collection - is not currently profitable through the recovery of the metals alone. Thus, a funding mechanism for Ni-Cd battery collection and recycling programs must be established before a program can be realistically implemented. 

Drag-line scrapers employ bucketlike scoops or disks which are moved back and forth by steel cables to drag loose materials from a large storage area, usually outdoors, toward a central elevator or conveyor hopper for subsequent delivery to the plant. Such equipment is used for storing and reclaiming materials like coal or stone. 

The fast growth of recycling helps in tire development of sttitable industries that provide reclaimed materials that meet ambitious specifications such as those of technical automotive parts [MAS 08, CAS 11]. 

As can be seen in Table 3.24, the energy consumption for the construction of a concrete layer is higher than that of the asphalt layer with virgin materials. Similarly, when 20% reclaimed material is used, the energy consumed for an asphalt base layer is less than that for an asphalt base layer with virgin materials. The processes that use unheated aggregate and cold applied binders utilise the least amount of energy per tonne. 

Travel plant mixing and blade mixing are used when the cold bituminous mixture is to be produced from virgin aggregate material. Rotary/reclaimer mixing is normally used when the cold bituminous mixture consists of reclaimed material. 

When reclaimed materials are to used in the Type I mixture, such as asphalt (Class R ) or other materials (Class X), the maximum permitted content recommended by the British specifications is less than 10% and 1%, respectively (% by mass) (Highways Agency 2009b). 

Pavement recycling leads to conservation and protection of the environment, since the use of RA not only delays the opening of new quarries but also solves the environmental problem of deposition of reclaimed material. 

Hot recycling in flexible pavements consists of removing the existing asphalt layer to a determined depth and replacing it with hot asphalt resulting from the same reclaimed material, with the possible addition of new material, that is, mixed in situ or new/recycled asphalt mixed in a central plant. 

Cold milling (or planning) is the removal of the existing asphalt layer to a desired depth determined by the surface/pavement deficiency to be corrected, using special machinery called milling machines or planners. The generated reclaimed material is removed from the site and stockpiled for future use (production of recycled asphalt or other usage). 

In situ full-depth cold recycling, also known as FDR or structural road recycling, is a cold recycling method where all asphalt layers and, in some cases, a predetermined portion of the underlying base material are uniformly pulverised and usually mixed with stabilising additives to produce a stabilised base course material. The pulverised reclaimed material may also be used as it is untreated for unbound base course material. 

The two-unit, or multiple-unit, cold in situ recycling trains provide the ultimate process control and quality of recycled mix. This is because the milled material may be crushed further, achieving better particle distribution, the oversized materials can be removed from the reclaimed material and the amount of recycling agents is directly related to the volume of reclaimed material. The latter ensures application rates of recycling agents as much as required. 

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