Metals - aluminium and steel recycling
Steel and aluminium are common metals in the UK and are produced and exist in large quantities. Their uses and usefulness were discovered thousands of years ago. Longevity, malleability, strength and conductivity -their properties have been used over the ages to provide us with the many goods we see today. They may be found in items as varied as cars, computers, buildings and packaging. Although UK per capita consumption of steel has dropped since the 1970s, aluminium use is still growing. Metals may remain for many years as viable products and so the environmental effects of their production will be lessened relative to using less durable materials.
World primary production of aluminium is around 24 million tonnes on average a year. The largest producer of aluminium is Australia, although other producer countries include Jamaica, Brazil, Guinea, China and parts of Europe.
World crude steel production stood at 1.05 billion tonnes in 2004. This represented a worldwide increase in production of 8.8% compared to 2003. Excluding China, world production rose by 4.5% in 2004.
Why bother?
Metals can be recycled indefinitely without loosing any of their properties. They make up around 8% of the average household dustbin yet in 2003 the recycling rates for aluminium and ferrous metals as a percentage of their consumption were only 33% and 26% respectively.
Aluminium
Aluminium is produced from bauxite, a clay-like ore that is rich in aluminium compounds. The aluminium is only found as a compound called alumina, which is a hard material consisting of aluminium combined with oxygen. This alumina has to be stripped of its oxygen in order to free the aluminium. The alumina is dissolved in a molten salt at a reduction plant and a powerful electric current is run though the liquid to separate the aluminium from the oxygen. This process uses large quantities of energy.
Recycling 1kg of aluminium saves up to 6kg of bauxite, 4kg of chemical products and 14 kWh of electricity.
Recycling aluminium requires only 5% of the energy and produces only 5% of the CO2 emissions as compared with primary production and reduces the waste going to landfill. Aluminium can be recycled indefinitely, as reprocessing does not damage its structure. Aluminium is also the most cost-effective material to recycle.
A recycled aluminium can saves enough energy to run a television for three hours.
If all the aluminium cans in the UK were recycled there would be 14 million fewer full dustbins each year.
Steel
Steel is also mined from an ore. Iron ore is plentiful but it too is usually combined with oxygen or sometimes carbon or sulphur. The iron ore is stripped in a blast furnace to reduce it to pig iron that can then be used in steel production.
There are currently about 11Mt per year of iron and steel scrap arisings. About 70% of this scrap is recovered. Of the remainder - 2/3 is landfilled.
Steel Facts and Figures
• Each household uses approximately 600 steel cans per year
• There are over 300million cans used per week over the xmas period
• The thinnest part of the can wall measures only 0.07mm thick - that's thinner than a human hair
• It would take 1087 steel drinks cans stacked end to end to reach the top of the London Eye or 2818 to reach the top of the Eiffel Tower
• The value of used steel cans in the waste stream is £28 milllion per annum which is available to collectors.
• Don't forget that 1.8 billion drinks cans are made of steel
• Millions of steel cans are collected every day by using huge magnets to pull them out of dustbin waste
• The recycling rate of all steel packaging is 46%; aluminum has a 23.4% packaging recycle rate .
• Steel cans are becoming lighter with the average weight of a soft drinks can in 2004 expected to be only 21.4g .In 1980 it was 31.2g
• There are over 2.5 billion cans recycled in the UK each year - [That's a saving of 125,000tonnes of solid waste every year] that's equivalent to the weight of 18,000 double decker buses!!
• All steel cans are 100% recyclable
• All steel cans contain up to 25% recycled steel
• Its not just food and drink cans made from steel! - most of your deodorants, hairsprays, polishes, paint cans and other household and DIY products are made out of steel too!
• Recycling one tone of steels cans saves 1.5 tonnes of iron ore ,0.5 tonnes of coal & 40% water usage
• Two-thirds of all cans on supermarkets shelves are made from steel
• Recycling 1 tonne of steel scrap saves 80% of the CO2 emissions produced when making steel from iron ore
• Recycling seven steel cans saves enough energy to power a 60-watt light bulb for 26 hours
Every tonne of steel packaging recycled makes the following environmental savings:
1.5 tonnes of iron ore0.5 tonnes of coal40% of the water required in production75% of the energy needed to make steel from virgin material1.28 tonnes of solid waste Reduction of air emissions by 86%Reduction of water pollution by 76%
Other metals
Although present in smaller quantities - all metals including nickel, copper, silver, gold, lead, brass and more, can be recycled. Given their recognised value a smaller quantity of these metals are in circulation however with reliance on these metals by specific industries eg electronics their presence is often neglected when householders dispose of items.
Scrap metal is divided into two types: ferrous and nonferrous. Ferrous scrap is scrap iron and steel. This includes scrap from old cars, household appliances, steel beams, railroad tracks, ships, and food packaging and other containers.
Nonferrous scrap metal is scrap metal other than iron and steel. Examples of nonferrous scrap include aluminium - including foil and cans, copper, lead, zinc, nickel, titanium, cobalt, chromium, and precious metals. Although there is less nonferrous scrap than ferrous scrap, it is often worth more financially. Millions of tonnes of nonferrous scrap metal are recovered by processors and consumed by secondary smelter, refiners, ingot makers, fabricators, foundries, and other industries.
Scrap metal, ferrous and nonferrous, can be categorized as either "home scrap" or "purchased scrap."
Home scrap is scrap generated at the mill, refinery, or foundry, and is generally remelted and used again at the same plant. Home scrap never leaves the plant.
Steel scrap is essential in the process of making new steel and can be recycled indefinitely without loosing its quality. Due to its magnetic properties it is easy to recover even from unsorted waste and residual waste at Energy from waste plants.
Aluminium foil, laminates (eg crisp packets) will oxidise in an incinerator and release energy similar to coal. Aluminium cans will usually melt releasing some energy and when cooled can be separated from the bottom ash.
Purchased scrap represents the fractions of the metals that need to be collected before they can be recycled. Large goods eg vehicles and fridges have historically been collected by scrap metal merchants owing to the value of the metal recovered. New legislation regarding the recycling of fridges and of end-of-life vehicles is changing the specific role of the metals recyclers in the collection and processing of these goods but their importance in recovering the metal components has not changed. Electronics recyclers are playing a bigger role in an economy in which waste electronics form an increasingly large part, not least because of new legislation.
As householders we are more commonly aware of the metal packaging we receive. Whereas plastic packaging may cause difficulties due to the disparate nature and need to separate it into its different types - metal packaging recycling is simpler. As the ferrous and non ferrous components can be separated using magnets one large problem of identification is solved. Whilst beverage cans remain the most popular choice for collection by local authorities - aerosol cans and aluminium foil are accepted by many.
Each year the UK uses around 600 million aerosols, which is equivalent to about ten cans per person; in total this represents almost 30,000 tonnes of reclaimable high grade metal that could be recycled each year. Approximately 85 per cent of aerosols are made from tin-plated steel, and the rest from high-grade aluminium.
Seventy-five per cent of Local Authorities are now collecting empty aerosols through either kerbside schemes or bring banks.
Steel packaging
Steel cans have a very thin layer of tin that protects the surface of the can, which is why steel cans are often called "tins". The average weight of this tin coating has decreased by 40% over the last 20 years and the average steel can now only weighs 22g compared to 34g twenty years ago. Although this has given great resource savings, throwing cans away still wastes valuable resources and adds to the amount of waste that has to be landfilled. As local authorities recognise benefits to be gained from including steel cans in their multi-material kerbside collection schemes, so recycling rates have risen. In 2003 44% of all steel packaging, including 2.5 billion steel cans, were recycled, but 9 billion steel cans are still going to landfill, this despite the fact that owing to the high price paid for steel, recycling collections can often be made at zero cost to the collector.
Aluminium packaging
75% of all canned drinks sold in the UK are packaged in aluminium. In 2001 the UK consumed 5 billion aluminium drinks cans, of which 42% were recycled. Although this is a great improvement on the 2% recycled in 1989, there were still a massive 3 billion cans that were landfilled.
Aluminium cans are recycled into new aluminium cans. Used beverage cans are normally back on supermarket shelves as new beverage cans in 6-8 weeks. With a growing percentage of cans made from aluminium, because of its lightweight qualities, this ensures a healthy market for aluminium can recycling.
Aluminium foil and aluminium cans are made of different alloys and must therefore be collected separately. Most recycled aluminium foil is used to make cast components for the automotive industry, such as cylinder heads and engine blocks.
When washed, foil milk bottle tops, tops of cartons, baking and freezing trays, kitchen foil, cigarette and tobacco foil (without the backing paper) are all suitable for collection. Metal coated plastic film, which is often used for crisp and snack packets, looks like aluminium but can not be recycled. Use the scrunch test to check whether it is aluminium foil. If it springs back when scrunched in the hand it is not recyclable!
Other metals
When considering metal recycling we generally refer to aluminium and steel. Other metals eg copper, gold, silver and brass are less frequently landfilled as their value is more generally recognised and consequently the recycling infrastructure more developed. That being said, handling of large quantities of electronic equipment in order to recover precious metals has led to the exporting of equipment to places where little regard is paid to the health or workers and the environmental consequences of poor treatment of this waste stream. For further details see our electronics information sheet.
Metals' recycling is effected through ELV, WEEE, and packaging legislation. For more details see our legislation information sheet.
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