More info at partner sites :
Saturday, August 4, 2007
Re-roofing America's homes with metal
Posted by
M. Yahya
at
1:24 PM
0
comments
Thursday, August 2, 2007
Story of Aluminium
Global society faces a great challenge to shift human economic activity and lifestyles on to a sustainable path in the 21st century, including meeting threats from climate change. The story of the aluminium industry over the decades ahead must be one of how it is part of the solution for a sustainable future.
This century began with an estimated 6 billion people on the planet, up six-fold in just 200 years from 1 billion in the year 1800. The United Nations currently expects global population to peak around 2050 at about 9 billion.
The sustainability challenge shared by all nations, industries and communities is to provide not only for the basic needs of all of these people, but to meet their expectations for improving quality of life. Crucially, this socio-economic progress must be achieved while ensuring that the natural environment remains ecologically viable and able to meet the needs of future generations as well as current ones.
The products of human ingenuity, including industrial creations such as the versatile metal aluminium, have a vital role to play in successfully addressing this sustainability challenge. To do its part, the aluminium industry needs to minimize environmental, social and economic negatives and maximize the positives across its life-cycle – from pre-mining to post-consumer stages - delivering a clear net benefit to society.
Why Aluminium?
The demand for aluminium products is increasing year by year, so why is aluminium a metal in such demand and what is its role in the lives of future generations?
Aluminium is a young material, and in the little more than a century since its first commercial production, it has become the world’s second most used metal after steel. Aluminium is the metal of choice for leading designers, architects and engineers, all of whom are looking for a material which combines functionality and cost-effectiveness with forward looking form and design potential.
Aluminium is an extraordinarily versatile material. The range of forms it can take (castings, extrusions and tubes, sheet & plate, foil, powder, forgings etc) and variety of surface finishes available (coatings, anodizing, polishing etc) means it lends itself to a wide range of products, many of which we use every day of our lives.
As well as its versatile form, the metal’s light weight (33% that of steel) and numerous material qualities – represented by a wide range of alloys – mean that products have been designed for use in all areas of modern life. It is a good conductor of electricity (one kilogram of aluminium cable can carry twice as much electricity as one kilogram of copper) and most overhead and many underground transmission lines are made of aluminium. It transmits conducted heat and reflects radiant heat, making it an excellent medium from which to produce cooking utensils and foils, radiators and building insulation. Its strength, combined with low density, make it ideal for transport and packaging applications. Aluminium is a unique metal: strong, durable, flexible, impermeable, lightweight, corrosion-resistant and 100 percent recyclable.
Aluminium is the third most abundant element in the earth's crust and constitutes 7.3% by mass. In nature however it only exists in very stable combinations with other materials (particularly as silicates and oxides). While there were some historical mentions of aluminium use, it was not until 1808 that its existence was first established. It then took many years of painstaking research to "unlock" the metal from its ore - the hard, reddish and clay-like bauxite. Further years of experimentation finally, in 1854, saw the development of a viable, commercial production process.
Aluminium is a young metal, having only been produced commercially for 153 years. Despite the fact that copper, lead and tin have been in use for thousands of years, today more aluminium is produced than all other non-ferrous metals combined. Its unique combination of properties makes it suitable for myriad applications. It has become the world's second most used metal after steel.Annual primary production of aluminium in 2006 was around 34 million tonnes and recycled production around 16 million tonnes. The total of some 50 million tonnes compares with 17 million tonnes of copper, 8 million tonnes of lead and 0.4 million tonnes of tin.
Posted by
M. Yahya
at
3:52 PM
0
comments
Waste Online
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.
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
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%
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.
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.
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!
Posted by
M. Yahya
at
2:57 PM
0
comments




