Rationale for Aluminium Recycling

Shredded aluminium beverage cans.
Image via Wikipedia

Aluminium is used extensively in aircraft, building construction, electrical transmission and consumer durables such as fridges, cooking utensils and air conditioners as well as in food processing equipment and cans. Infact, the use of aluminum exceeds that of any other metal except iron. Aluminium is the second most widely used metal whereas the aluminum can is the most recycled consumer product in the world. Aluminium exposed to fires at dumps can be a serious environmental problem in the form of poisonous gases and mosquito breeding. Recycled aluminium can be utilized for almost all applications, and can preserve raw materials and reduce toxic emissions, apart from significant energy conservation.

The demand for aluminium products is growing steadily because of their positive contribution to modern living. Aluminium finds extensive use in air, road and sea transport; food and medicine; packaging; construction; electronics and electrical power transmission. Aluminum has a high market value and continues to provide an economic incentive to recycle it. The excellent recyclability of aluminium, together with its high scrap value and the low energy needs during recycling make aluminium lightweight solutions highly desirable.

The contribution of the recycled metal to the global output of aluminium products has increased from 17 percent in 1960 to 34 percent today, and expected to rise to almost 40 percent by 2020. Global recycling rates are high, with approximately 90 per cent of the metal used for transport and construction applications recovered, and over 60 per cent of used beverage cans are collected.

Aluminium does not degrade during the recycling process, since its atomic structure is not altered during melting. Aluminium recycling is both economically and environmentally effective, as it requires a lot less energy to recycle than it does to mine, extract and smelt aluminium ore.  Recycled aluminium requires only 5% of the energy used to make primary aluminium, and can have the same properties as the parent metal. However, in the course of multiple recycling, more and more alloying elements are introduced into the metal cycle. This effect is put to good use in the production of casting alloys, which generally need these elements to attain the desired alloy properties.

The industry has a long tradition of collecting and recycling used aluminium products. Over the years, USA and European countries have developed robust separate collection systems for aluminium packaging with a good degree of success. Recycling aluminium reduces the need for raw materials and reduces the use of valuable energy resources. Recycled aluminium is made into aircraft, automobiles, bicycles, boats, computers, cookware, gutters, siding, wire and cans.

Enhanced by Zemanta

Increasing use of Plastics and its Recycling

Plastic consumption has grown at a tremendous rate over the past two decades as plastics now play an important role in all aspects of modern lifestyle. Plastics are used in the manufacture of numerous products such as protective packaging, lightweight and safety components in cars, mobile phones, insulation materials in buildings, domestic appliances, furniture items, medical devices etc. Plastics are used because they are easy and cheap to make and they can last a long time. Disposal of plastic waste has emerged as an important environmental challenge and its recycling is facing roadblocks due to their non-degradable nature. Because plastic does not decompose biologically, the amount of plastic waste in our surroundings is steadily increasing. More than 90% of the articles found on the sea beaches contain plastic. Plastic waste is often the most objectionable kind of litter and will be visible for months in landfill sites without degrading.

Recycling and reuse of plastics is gaining importance as a sustainable method for plastic waste disposal. Unfortunately, plastic is much more difficult to recycle than materials like glass, aluminum or paper. A common problem with recycling plastics is that plastics are often made up of more than one kind of polymer or there may be some sort of fibre added to the plastic (a composite). Plastic polymers require greater processing to be recycled as each type melts at different temperatures and has different properties, so careful separation is necessary. Moreover, most plastics are not highly compatible with one another. Apart from familiar applications like recycling bottles and industrial packaging film, there are also new developments e.g. the Recovinyl initiative of the PVC industry (covering pipes, window frames, roofing membranes and flooring).

Polyethlene terephthalate (PET) and high density polyethylene (HDPE) bottles have proven to have high recyclability and are taken by most curbside and drop-off recycling programs. The growth of bottle recycling has been facilitated by the development of processing technologies that increase product purities and reduce operational costs. Recycled PET and HDPE have many uses and well-established markets.

In contrast, recycling of polyvinyl chloride (PVC) bottles and other materials is limited. A major problem in the recycling of PVC is the high chlorine content in raw PVC (around 56 percent of the polymer’s weight) and the high levels of hazardous additives added to the polymer to achieve the desired material quality. As a result, PVC requires separation from other plastics before mechanical recycling.