2017-05-15 13:06:43

Recycling Aluminium Construction Materials

Background

Aluminium is a product with unique properties, making it a natural partner for the building industry. Thanks to its strength, durability, corrosion resistance and recyclability, it has become an essential product for the building industry and over the past 50 years its use in building applications has shown continuous and consistent growth.

Applications of Aluminium in Construction and Building

Aluminium extruded, rolled, and cast products are commonly used for window frames and other glazed structures ranging from shop fronts to large roof superstructures for shopping centres and stadiums; for roofing, siding, and curtain walling, as well as for cast door handles, catches for windows, staircases, heating and air-conditioning systems. Most recently, aluminium has played a significant role in the renovation of historic buildings. The characteristics and properties of aluminium as a material have lead to revolutionary and innovative changes in building techniques and architectural and engineering projects. Aluminium is leading the way into the future of the construction industry.

Recycling Aluminium Construction Materials

In addition to their particularly long service life, aluminium construction industry products can either be used after dismantling or indefinitely recycled, without any loss of the materials’ basic qualities and properties. The use of recycled aluminium also offers substantial energy benefits. Remelting used aluminium requires only 5 per cent of the energy needed to produce primary metal. Thus, rather then contributing to society’s growing waste problem, aluminium can be remelted and reformed to produce a new generation of building parts.

Reasons Why So Much Aluminium is Recycled

Aluminium in general has always been recycled at a higher rate than most other raw materials. Given the necessary infrastructure, it is possible to recycle all aluminium construction industry applications, for several reasons. First, there is a relatively high level of scrap aluminium available. Second, aluminium has a high scrap value which can contribute significantly towards covering demolition costs. Finally, the infrastructure required for the collection of scrap metals is already well-established and will continue to grow on its own economic merit as it has done in the past to provide an increasingly efficient recycling system.


Aluminium Recovery Rates

Nearly 40 per cent of all aluminium used today is remelted metal. However, this does not give a true picture of the recovery ratio that can be achieved in the construction industry, as the durability of aluminium building industry parts makes the material unavailable for recycling for many years.

Pretreating Aluminium Connected to Other Scrap

Aluminium scrap collected from construction applications is sometimes attached to other materials, such as resins or foam insulation products. The scrap is pretreated to eliminate such waste. Consequently harmful emissions produced by the burning of such waste materials during the remelting are minimised or avoided and the purity pf the remelted metal is therefore ensured. In general, however, aluminium construction products do not need to be protected by organic coatings used to safeguard some alternative materials. They therefore offer a source of good metal which can be recycled without any pre-processing.

Separating Aluminium from Other Scrap

Finally, aluminium is easily separated from other metal scrap. To facilitate this operation, the raw scrap is first broken down through cutting or crushing in fragmentation plants. Ferrous scrap can then be removed by magnetic devices, while non-magnetic scrap that differs in density from aluminium can be sorted in heavy liquor separation equipment. Alternatively, aluminium can be separated directly by using eddy-current sorting machines.
Energy Efficiency.

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