Recycling of aluminum scrap
Role of Secondary Aluminum
Currently, the share of secondary aluminum - aluminum, which is obtained from aluminum scrap and wastes - it is about one third of the total world production of aluminum and, respectively, aluminum products. The main reasons for the recycling of aluminum scrap are the economic benefits and environmental protection. Secondary aluminum production requires the expenditure of only about 5 % energy from the energy, which is spent on the production of primary aluminum.
In the Western world, the level of industrial processing of aluminum is very high: from 60 % for aluminum beer cans before 85 % in construction and to 95 % in transport. Quality of aluminum during processing, basically, It does not decrease - it can be recycled - refiner - almost indefinitely. This especially applies to industrial scrap - industrial waste: almost 100 % This scrap is typically processed at once in the same aluminum alloy.
Scrap aluminum cans for beer and soft drinks
Details of sorting and recycling of aluminum scrap:
Handbook of aluminium recycling /Ch. Schmitz – 2014
Aluminium recycling /M. Schlesinger – 2017
Whither secondary aluminum
Most secondary aluminum - about 70 % - is the production of aluminum-silicon casting alloys, which are mainly used for the manufacture of car parts. The second major proportion of recycled aluminum is used for making sheet products and extruded products, including, profiles. A small portion of secondary aluminum is used as a deoxidizer in steel mill.
In 1990 , global aluminum production was about 28 million tons, of which 8 million tonnes was derived from scrap. In 2008 the total world production of aluminum was 56 million tons, of which 18 million tons - is secondary aluminum. TO 2020 year aluminum production is expected to rise to 96 million tons, of which 31 million tonnes will be recycled aluminum.
Aluminum scrap: old and new
Currently, about 50 % aluminum scrap in the world - this is the "old" scrap, ie scrap, which is obtained from the products, who exhausted their service life. Since the 1940s in Europe and North America has accumulated a significant amount of aluminum scrap, which led to the development of a powerful industry of its processing.
After the energy of the 1970s crisis, Japan closed its production of primary aluminum and 1980s switched to the production of secondary aluminum.
Remelted scrap in China
In recent 20 years there has been significant development of secondary aluminum production in developing countries in Asia, special, in China. Low labor costs gives them a significant competitive advantage in comparison with Western countries. Therefore, in recent years it formed a strong - and increasing - flow of scrap aluminum from North America and Europe to these countries.
Sorting of scrap aluminum in China
Business recycled aluminum
Usually in most countries, there is a well-organized market of aluminum scrap, with clearly defined flows of its receipt and distribution. Usually, in this market there are two types of secondary aluminum producers, which in English is called «refiners» and «remelters».
First - «refiners» – producing casting aluminum alloys and aluminum for steel deoxidation of the "old" scrap and industrial waste aluminum. They supply their products in the form of ingots or in liquid state. Besides introducing alloying elements, standards which require, These «refiners» can handle molten flux, to improve metal quality by removing oxides and intermetallics, and, sometimes, remove such elements, as magnesium and calcium.
Second - «remelters» – produce wrought aluminum alloys, and, primarily, pure and sorted scrap wrought aluminum alloys. They supply their products in the form of slabs for rolling, ingots-pillars for pressing (extrusion) and ligature ingots. alloys, they deliver, meet standards - national and international - and / or technical requirements of customers.
Sources of aluminum scrap
The value of scrap aluminum has been known for many years ago. However, the first push to increase production of secondary aluminum served as a "modest" Aluminum beer can. It became in 1970 the face of secondary aluminum production. Intense propaganda campaign for the collection of aluminum cans has created confidence the true value of aluminum scrap. This also contributed to the efforts of the government and municipal authorities in many countries to limit the amount of landfill waste and the environment.
Aluminum packaging products
Aluminum packaging, which include aluminum beer cans, It is only about 12 % global aluminum consumption. Nonetheless, it is very important for the secondary aluminum industry because of the relatively short life cycle of packaging. New types of packaging, such as aluminum unscrews cork wine bottles, give new volumes of aluminum for the production of secondary aluminum.
Aluminum in transport
Transport remains the most important consumer of aluminum products. for instance, c 2007 year, nearly 30 % wrought and cast aluminum alloys "went" in transport, cars, train, vessels, planes and the like. Those secondary aluminum producers, which is called «refiners», supply about 70 % its production is in the automotive industry. This contributes to a constant pressure by governments to reduce pollutant emissions car, which leads to an increase in aluminum automotive applications to reduce their weight. Therefore, in the past 40 years of aluminum in cars is becoming more and more. With an average lifetime of the car around 12 years and a huge amount of them, they are a very important source of raw materials for the production of secondary aluminum.
The construction industry consumes around 25 % global production of aluminum. However, aluminum construction products, in particular, aluminum windows and doors, They have a rather long life cycle - about 35-40 years. Therefore, only in the last 10-15 years the construction industry has become a significant source of aluminum scrap.
Source: G. Wallace //Fundamentals of aluminium metallurgy. Production, processing and applications / ed. R. Lumley, 2011.
The international code of aluminum recycling