VOA慢速英语2015 废金属分离技术成本可能会降低（在线收听）

AS IT IS 2015-03-25 Scrap Metal Separation May Become Less Costly 废金属分离技术成本可能会降低

Recycling, or re-using, metals is much less costly than making them from raw materials in the Earth, called “ore.” But when old cars, household appliances and industrial equipment are thrown away, metals are mixed and often difficult to separate. So they are usually placed into landfills without being separated.

The United States Environmental Protection Agency says almost 15 million tons of this “scrap” metal is placed into landfills every year.

Although iron and steel are easily separated with strong magnets, other metals, such as copper, aluminum and titanium, are not. So products with a mix of these metals are either sent to landfills or to other countries, where workers separate the different metals by hand. But university scientists working with a private company say they have created a very accurate method to separate these light metals, using a machine.

Don Eggert is the founder of O2M Technologies. His company worked with the University of Utah to develop the metal separation technology. Mr. Eggert says the system is based on the knowledge that all metals react to a strong magnetic field.

“When the metal falls through the field, even (if/though) it’s non-ferrous, it’s not attracted to the magnet, but the magnet causes there to be an electric current inside the metal, and that causes the metal to have a magnetic field itself, which interacts with the magnetic field that it’s falling through and pushes it to the side.”

Mr. Eggert says changing the frequency of the magnetic field causes metal pieces to fall into different containers.

“So, for example, if we want to separate aluminum and copper we hit the right frequency for it and the aluminum would push more (further) away from the magnet than the copper will. So the copper falls straight down, (and) the aluminum falls into a different bucket.”

Mr. Eggert says the separator is not costly to build.

Words in This Story

appliance – n. a machine (such as a stove, microwave or dishwasher) that is powered by electricity and that is used in people’s houses to perform a particular job

accurate – adj. able to produce results that are correct; not making mistakes

ferrous – adj. of, relating to or containing iron

magnetic field – n. of or relating to a magnet or magnetism; the magnetic effect of electric currents and magnetic materials

frequency – n. the number of times that something such as a sound wave or radio wave is repeated in a period of time

“What we have calculated so far is that the expense-to-value ratio -- that is, how quickly you can pay back the cost of the technology over time -- we’re currently estimating it to be less than one year.”

The separator works only with metal pieces up to one centimeter wide. But the researchers are building a bigger magnet to separate larger metal parts. They hope to begin operating it at a metal shredding center by the end of this year. There, they will be able to test it in a real-life environment.