DEVELOPMENT
REPORT - Recycling Scrap Metal
By Gary Garriott
This is the VOA Special English Development Report.
People have been recycling（反复使用）metals
for hundreds of years. Today, re-using metal waste or scrap（废料）provides
work for many people, especially in developing countries. Three kinds
of metals are recycled. They are ferrous metals（黑色金属）,
non-ferrous metals（有色金属）and precious
metals（贵金属）.
Ferrous metals contain iron. They are low in cost
and recycled in huge amounts. Metallic iron（精练铁）called
pig iron（生铁）is produced when iron is
heated in a hot industrial stove. This kind of stove is called a blast
furnace（鼓风炉）. Pig iron also contains another element, carbon（炭）.
Pig iron is useful because it can be formed into solid, heavy objects
or objects with unusual shapes.
Another kind of iron is steel, which is iron without
the carbon. Making steel is simply removing the carbon by burning it
away. This makes the steel stronger and easier to cut than iron. Both
pig iron and steel waste or scrap are useful because they can be melted
to make new products.
In countries where there is a shortage of steel scrap,
old tin cans are sometimes used and melted. Tin cans are mostly steel.
If the scrap is heated before the temperature gets to the melting
point（熔点）, the blast furnace can be more simply designed and
less costly. These simpler furnaces are called foundries. Products are
made in foundries all over the world, but especially in Asia.
Non-ferrous metals include copper（铜）and
aluminum（铝）. Copper is the perfect material
for recycling. It is valuable, easy to identify and easy to clean. People
who operate foundries around the world buy copper wire and cable to
recycle.
Aluminum is another very popular non-ferrous scrap
metal. It is cheap to produce and very easy to work with. In developing
countries, small foundries produce aluminum bars, sheets and wire.
Precious metals like silver also are recycled. Silver
can be found in pictures made with an old black-and-white camera. And
it can be found in X-rays after they have been developed. X-ray film
is very valuable for recycling silver, because both sides of the film
are usually developed.
You can learn more about recycling metals from Volunteers
in Technical Assistance, or VITA. VITA is on the Internet at vita.org.
This VOA Special English Development Report
was written by Gary Garriott.
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