Waste-derived materials

Table 6. Summary of adsorption capacities of selected waste-derived materials...

Refuse-Derived Fuel. Many processing faciUties divert a portion of the material that is not recovered for recycling to waste-to-energy plants, also referred to as resource recovery faciUties, where the material is employed as fuel. The processes involved in the production of refuse-derived fuel (RDF) are outlined in Figure 4 (23). Nine different RDFs have been defined, as Hsted in Table 3 (24). There are several ways to prepare RDF-3, which is perhaps the most popular form and is the feed used in the preparation of densified refuse-derived fuel (d-RDF). AH forms of RDF are part of the broader set of waste-derived fuels (WDF), which includes various waste biomass, eg, from silvaculture or agriculture (see Fuels frombiomass Fuels fromwaste). 

The waste from the separation is called waste-derived fuel (WDF) or solid recovered fuel (SRF). It is normally composed of materials with good calorific power, such as paper, plastics, fabrics, and wood. These materials are only the rejects that cannot be recycled, due mainly to the level of contaminants they contain. 

In fact, RDF is a category of the generic class of waste-derived fuel (WDF). RDF has not been given the universe definition it depends on the technologies and methods of each sector and each country. The American Society for Testing and Materials (ASTM) has defined several forms of RDF as shown in Table 4 [9]. 

Despite of 150-year s history of vulcanization process, it is impossible to consider that fundamental and applied researches in direction of vulcanization systems perfection are completed. For today one of the ways of rubbers properties improvement is the synthesis and application of the new chemicals-additives, including, vulcanization active, that is connected, first of all, with reduction of global stocks of zinc ores as basic raw material for reception of traditional activator - zinc oxide. Besides, modem increase of industrial potential and the accumulation of big quantity wastes derivate the problems of ecological character, which require the emergency decision. Therefore creation of resourcesaving technologies of the new compounds reception from products of secondary raw material processing has paramount importance. 

DPE suits, and butyl rubber (NRC, 2001b). The levels were 0.0002 to 0.0008 ng/m3, three orders of magnitude below the EPA criterion of 0.2 ng/m3 for dioxin emissions from incinerators. In the test with neat GB, the product gas contained 0.01 to 0.06 percent phosphine. As noted previously in the section on methods development testing, phosphine can interfere with the measurement of GB. Based on results from the EPA s toxicity characteristic leachate procedure, stabilization would be necessary only for solid wastes derived from DPE suit material, because the cadmium and lead criteria were not met by the treated dunnage in some tests (NRC, 2001b). 

Furan-2,5-dicarboxylic add also has tremendous industrial potential, because it could replace oil-derived diadds such as adipic or terephthalic acid as monomers for polyesters and polyamides [98, 99]. This diadd can be synthesized by Pt-catalyzed oxidation with 02 of 5-hydroxymethylfurfural the latter is obtained by acid-catalyzed dehydration of D-frudose or frudosans (inulin) the latter, however, are too expensive as starting materials, and yields from glucose-based waste raw materials are no higher than 40%. Therefore, the potential attractive option of furan-2,5-dicarboxylic acid will develop only after an effident generation of 5-hydroxymethylfurfural from forestry waste materials has been developed. The same compound is also the starting material for the synthesis of other interesting chemicals obtained by oxidative processes, such as 5-hydroxymethylfuroic add, 5-formylfuran-2-carboxylic add and the 1,6-dialdehyde. 

McGhee B., Norton F., Snape C. E. and Hall, P.J. (1995). The Copyrolysis of Poly (vinylchloride) With Cellulose Derived Materials as a Model for Municipal Waste. Fuel 74, pp. 28 -31... 

The first unit operation in the production of waste or biomass derived activated carbon is pyrolysis, also known as baking or charring. In this process the material is heated in an essentially oxygen-free atmosphere to drive off the free moisture and volatiles. The material that remains is called char or fixed carbon. The char yield is dependent upon heating rate and in a study performed by Roberts et al. (1978) on the production of municipal solid waste derived activated carbon, the following... 

This process will allow the recycling of solid waste to produce a useful product. High pressure and temperature combined with hydrogen can convert most types of domestic and industrial wastes back into products that are currently obtained from fossil coal and oil. No volatile polluting chemicals will be vented into the atmosphere. The metals can be recovered for further use and the ceramic materials will be converted into a product difficult to distinguish from natural rocks. This type of process will not solve all the solid waste disposal problems, but will provide a potential method for recovery of valuable products from waste. When implemented, it will dramatically reduce the amount of solid waste placed in landfills. This process also has the potential to reduce the amount of oil and coal mined to provide the carbon compounds needed to manufacture all petrochemical derived materials. This waste reduction process is a variation on the Fischer-Tropsch process, mentioned on page 101, in use commercially to produce hydrocarbon materials from coal. 

Nuclear waste is divided into three categories. High-level waste, which is the most radioactive component, forms about 0.2 % of the whole. It is derived mainly from weapons applications and spent nuclear fuel rods. In addition there is about 20% intermediate-level waste, which arises from similar sources and is increased by materials used in reprocessing. This component is not very radioactive and does not liberate large amounts of heat. The remainder, described as low-level waste, is material that is slightly radioactive. Apart from military and nuclear energy sources, this material comes from hospitals, research laboratories and industry, and includes contaminated paper towels, gloves and laboratory equipment. 

Clinker inhomogeneity Lower reactivity of ash, too short retention time at clinkering temperature, high ash content, lump coal for precalcining carbon-rich fly ash as a raw material, waste-derived fuels containing graphite (Sprung, 1985)... 

Contaminated wastes derive from the fabrication of weapon components and related activities also. Further, the end of Cold War resulted in closing weapons production facilities and the creation of decontamination products, surplus plutonium, and other radioactive materials. These materials have to be safely disposed so that they do not cause any harm to public health or the environment. Moreover, they have to be secured so that they carmot be easily recovered and reused. 

Ag, As, Ba, Be, Cd, Cr, Hg, Pb, Sb, 71 Coal, coke, cement raw, feed materials, waste derived fuels Microwave acid digestion Not specified ASTM D5513-94 industrial furnace feedstreams for trace element analysis... 

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