Construction aluminum scrap
Aluminum properties, which make it a valuable material in construction, are:
- low density;
- high corrosion resistance;
- the ability to obtain the optimal shape of profiles by pressing (extrusion).
The use of aluminum in the construction of
Examples of the use of aluminum due to these three of its advantages are [1]:
- mobile military bridges;
- frames of windows and doors;
- fences and railings;
- ship ladders;
- greenhouses and greenhouses;
- facing of building facades;
- enclosing facade structures;
- flagpoles;
- mobile and bridge cranes;
- stairs;
- automatic doors;
- road sign supports;
- electrical supports.
Most alloys, which he is used in construction, are deformable alloys, in particular, alloys of 5xxx and 6xxx series. Most often used here are such aluminum alloys as:
- 3103, 3105,
- 5005, 5083, 5085, 5754,
- 6005, 6060, 6061, 6063 and 6082.
Most aluminum products in this segment have begun to be used recently., and their service life is quite long - usually years 20, and often 50 years. Therefore, the share of old aluminum scrap from the construction industry is gradually increasing: from zero in the late 1990s to 10-15 % in the 2010s.
Harmful impurities of construction scrap
Sources of contaminants and potential pollutants, contained in aluminum construction scrap, are [1]:
- ceramic materials, turn on the brick, concrete and glass;
- organic decorative and protective coatings;
- dirt and paint;
- polymers, including plastic and rubber;
- steel parts, including those, which are attached to aluminum.
Dismantling the facade structure: return 98,3 % aluminum
Since the 1970s, a huge number of buildings with an outer cladding in the form of aluminum curtain facades were built around the world. Many of these buildings are currently undergoing major renovations or demolitions.. Due to its design, aluminum facade structures are easy to dismantle and are almost completely returned for remelting. Walling, such as curtain walls, windows and doors, usually, made of aluminum alloys 6060 and 6063.
Figure 1 - Construction aluminum scrap [2]
The efficiency of recycling aluminum scrap from dismantling aluminum facades is demonstrated in the "case" of the European Aluminum Association [2]:
- In 2020 the outer shell of the office building was dismantled.
- According to the design documentation, the external aluminum structures of the building contained more than 28 tons of aluminum:
– facade structures: extruded aluminum alloy profiles 6060 or 6063
– wall cladding: sheet aluminum from 3xxx series aluminum alloys
– building canopy: most likely, sheets of 5xxx series alloys. - As a result of the dismantling of the outer shell 98,3% from the total weight of aluminum structures were collected and sent for remelting for the production of new aluminum products (figures 3 and 4).
Figure 2 - Dismantling of aluminum structures of the building [3]
Figure 3 - Collection of construction aluminum scrap at the construction site [3]
Figure 4 - Sorting and processing of construction aluminum scrap [3]
Collection of aluminum building structures and products, which have reached the end of their service life, is very important, as it allows this valuable aluminum scrap to be recycled into new aluminum products. It also reduces waste from the construction industry., that, for example, in Europe, constitute the largest "garbage" stream by weight [2].
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