Recycling Recycling is the process of converting waste materials into new materials and objects. The Energy recycling, recovery of energy from waste materials is often included in this concept. The recyclability of a material depends on its ability t ...

can be carried out on various

raw materials A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feeds ...

. Recycling is an important part of creating more sustainable economies, reducing the cost and environmental impact of raw materials. Not all materials are easily recycled, and processing recyclable into the correct waste stream requires considerable energy. Some particular manufactured goods are not easily separated, unless specially process therefore have unique product-based recycling processes.

Asphalt

Asphalt concrete removed during road maintenance, resurfacing, and repair activities can be reclaimed and reused in new pavement mixtures, as an unbound aggregate base, or other civil engineering applications. Very little asphalt concrete — less than 1 percent, according to a survey by the

Federal Highway Administration The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program ...

and the National Asphalt Pavement Association conducted annually since 2009 — is actually disposed of in

landfill A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the wast ...

s. When asphalt pavement material is reclaimed for reuse, it is able to replace both virgin

aggregate Aggregate or aggregates may refer to: Computing and mathematics * collection of objects that are bound together by a root entity, otherwise known as an aggregate root. The aggregate root guarantees the consistency of changes being made within the ...

s and virgin asphalt binder. Similarly, asphalt

roof shingle Roof shingles are a roof covering consisting of individual overlapping elements. These elements are typically flat, rectangular shapes laid in courses from the bottom edge of the roof up, with each successive course overlapping the joints below ...

s can be recycled for use in new asphalt pavements.

Concrete

Glass

Metals

Aluminium

Aluminium is one of the most efficient and widely recycled materials.

Aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...

is shredded and ground into small pieces or crushed into bales. These pieces or bales are melted in an aluminium smelter to produce molten aluminium. By this stage, the recycled aluminium is indistinguishable from virgin aluminium and further processing is identical for both. This process does not produce any change in the metal, so aluminium can be recycled indefinitely. Recycling aluminium saves 95% of the energy cost of processing new aluminium. This is because the temperature necessary for melting recycled, nearly pure, aluminium is 600 °C, while to extract mined aluminium from its ore requires 900 °C. To reach this higher temperature, much more energy is needed, leading to the high environmental benefits of aluminium recycling. Americans throw away enough aluminium every year to rebuild their entire commercial air fleet. Also, the energy saved by recycling one aluminium can is enough to run a television for three hours.

Copper

Iron and steel

Iron and steel are the world's most recycled materials, and among the easiest materials to reprocess, as they can be separated magnetically from the waste stream. Recycling is via a steelworks: scrap is either remelted in an

electric arc furnace An electric arc furnace (EAF) is a furnace that heats material by means of an electric arc. Industrial arc furnaces range in size from small units of approximately one-tonne capacity (used in foundries for producing cast iron products) up to ...

(90-100% scrap), or used as part of the charge in a Basic Oxygen Furnace (around 25% scrap). Any grade of steel can be recycled to top quality new metal, with no 'downgrading' from prime to lower quality materials as steel is recycled repeatedly. 42% of crude steel produced is recycled material.

Other metals

For information about recycling other, less common metals, refer to: * Bismuth recycling * Lead recycling

Plastic

Timber

Recycling timber has become popular due to its image as an

environmentally friendly Environment friendly processes, or environmental-friendly processes (also referred to as eco-friendly, nature-friendly, and green), are sustainability and marketing terms referring to goods and services, laws, guidelines and policies that cl ...

product, with consumers commonly believing that by purchasing recycled wood the demand for ''green timber'' will fall and ultimately benefit the environment.

Greenpeace Greenpeace is an independent global campaigning network, founded in Canada in 1971 by Irving Stowe and Dorothy Stowe, immigrant environmental activists from the United States. Greenpeace states its goal is to "ensure the ability of the Earth t ...

also view recycled timber as an environmentally friendly product, citing it as the most preferable timber source on their website. The arrival of recycled timber as a construction product has been important in both raising industry and consumer awareness towards deforestation and promoting

timber mill A sawmill (saw mill, saw-mill) or lumber mill is a facility where logs are cut into lumber. Modern sawmills use a motorized saw to cut logs lengthwise to make long pieces, and crosswise to length depending on standard or custom sizes (dimensi ...

s to adopt more environmentally friendly practices.

References

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