Describe the methods for recycling metals, including information on
which metals are the easiest and/or most cost effective to recycle.

Hi! Thanks for the question.

I have found the following resources which discussess the topic of
metal recycling.

"The most common metals we need to consider when discussing recycling
are aluminum and steel. Some other metals–like gold, silver, brass,
and copper–are so valuable that they are rarely thrown away. They do
not create a waste disposal problem."

"The tricky thing about aluminum—unlike copper, iron, and other common
metals—is that it only exists in combination with other elements,
usually oxygen. Combined with oxygen, aluminum forms an extremely hard
material known as alumina. To free the aluminum, the alumina must be
stripped or reduced of its oxygen. This process is done at a reduction
plant, or smelter. The alumina is put into large pots at the reduction
plant. First, it is dissolved in a molten (or liquid) salt."

"Then, a powerful electric current is run through the liquid to
separate the aluminum from the oxygen. The molten aluminum sinks to
the bottom of the pots. The reduction process requires a tremendous
amount of electrical energy."

"Steel is probably the easiest material to separate from the rest of
the solid waste stream. Steel is attracted to magnets, so special
magnetic belts can be used to separate steel cans from other
recyclables. This is a much more efficient method than the
labor-intensive hand-sorting necessary with other recyclables, such as
plastics."

"Recycling your used steel cans at home is easy, too. All you need to
do is rinse the food from the cans. That’s it. Years ago, scrap
dealers asked people to remove the paper labels and the tops and
bottoms from cans. This is no longer necessary."

"Recycling Metals"
http://www.eia.doe.gov/kids/recycling/solidwaste/metals.html

Our next link is a more detailed discussion of the recycling process
for different types of metals. The article discusses the different
processes for recycling steel, aluminum, copper, lead and zinc. The
page that concerns you most will be page 28 up to page 39.

"RECYCLING METALS FOR THE ENVIRONMENT"
http://www.seas.columbia.edu/earth/papers/aree98.pdf

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Easterangel-ga                      
Google Answers Researcher

Umm, that didn't answer the question, and I didn't even ask it.  In
particular, the Aluminum part is 100% wrong, since what is written
about it is actually what makes Al so important to recycle, since
getting new Al from bauxite or its ore, is very energy intensive and
that's what is described. In fact, although iron, and its alloys
(steels) are easy to seperate, Al is by far the most profitable to
recycle.

Thanks leoj-ga for sharing your insights.

Please take note however that the first resource I cited came from the
Department of Energy website so it is evident that they are very
knowledgeable as regards these matters. The second link I cited, which
is an academic paper, meanwhile came from a reputable organization as
well... Columbia University.