ASR recycling technology makes advancements
Fifteen million tons of scrap automobiles, appliances
and other light metal products are shredded annually in the United
States. Twelve million tons are recycled, leaving the country’s
200 automobile shredding facilities searching for a viable economic
model in order to recycle this automobile shredder residue (ASR).
With nearly 220 million registered vehicles in
the United States, the amount of ASR has been consistent for the
past two years.
It is the three millions tons (20 percent) of
shredder residue (SR) – approximately one percent of the total
waste placed in landfills annually – that presents a problem.
The SR can either be recovered by either converting
it into liquid or gaseous fuels or by recovering the actual rubber
and plastic products.
“They are expensive,” said Bob Boughton,
a senior hazardous substances engineer with the California Department
of Toxic Substances Control. “The economics don’t work
well in the U.S. and that is mainly why nobody is doing anything
with it. It just costs too much to try and separate the materials
before you shred by dismantling or after you shred materials, which
are just so co-mingled and maybe have too many different constituents
in it, which is very difficult to manage.
“The other twist is that most of the shredders
are also shredding appliances and scrap steel, so maybe 50 percent
of SR comes from automobiles,” he added. “We are also
getting plastic and rubber from all these other materials –
various appliances – all being mixed together and this is
happening almost everywhere in the country.”
Of the 50 states, only California has labeled ASR as a hazardous
waste and requires special steps to prepare it prior to being deposited
For the other states, only when PCB and other
materials are found at certain levels, do national and state legislation
kick in to deal with them.
Due to concerns about levels of leachable heavy
metals, California implemented its requirements.
“It could be sent to a hazardous waste landfill,
but that would be expensive,” said Boughton, “so everyone
here is treating their residue with some silicate-type treatment
and Portland cement and cement kiln dust fly ash solidification
materials that reduce the heavy metals from leaching. Then they
can landfill it as regular garbage.”
European nations are seeking solutions due to
recycling mandates imposed by the European Union. Currently EU nations
are recycling 75 percent of automobiles – copper, aluminum
and steel. The EU mandate requires an 85 percent level, which will
eventually be raised to 95 percent.
Product stewardship is seen as one way of reducing
“One way is to reduce the materials in the
manufacturing of the car at the beginning, but that is counter to
putting more plastics on vehicles to make them lighter weight so
that you get better gas mileage,” said Boughton. “So
instead of having all the different types of plastics, they are
trying to just get several types, make cars easier to dismantle
and to exchange parts, but you are going to have 10 year old cars
that are ending their service life, which is generating SR right
now. This is really a problem.”
In addition to dismantling, creating fuel and
recycling plastic and rubber, glass and inert dirt material is being
studied as an aggregate for asphalt and concrete, and soil application.
While these measures are costly, Boughton says
they are being pursued because legislation is serving as a “driving
force and they are having to eat the cost as far as the automakers.
I don’t think anyone in the United States is currently recovering
anything for SR, although several groups are studying ways to do
Research on the use of ASR is being conducted
by car and major automobile manufacturers, as well as the Argon
National Labs, which is studying processes and has actually recovered
the foam in some plastics for re-use.
“They are still fine tuning those processes
– nobody is doing anything full-scale,” said Boughton.
“It’s pretty easy as far as technology to convert materials
into liquid or gas fuels or to just burn it like you can burn garbage,
but nobody is really doing that. People have tested it as a fuel
after processing such as steel mills and other specific applications,
but the problem is that you have to get all the chlorine out; you
have to clean it and do several separations. By the time you do
that, it becomes a ridiculous cost.
“The problem in California and other states
is that it is still reasonably cheap to landfill – the average
cost is $35 per ton,” he added. “In the eastern United
States it may cost $100 a ton to landfill. There are probably better
economics there for recovery of shredder residue.”
Nor does Boughton see any national leadership
to deal with the ASR problem.
“It’s one of those ‘not really
a problem’ issues,” he said, but noting that several
years ago that the federal and state governments expressed an interest
in using SR as alternative spread to cover garbage at landfills
due to its inert qualities and inability to catch fire.
While an agreement with dismantlers has been signed
to remove mercury switches, which should help to reduce mercury
emissions in shredders, as well as mercury residue, action is still
needed on other metals that are used in automobiles.
Boughton is hoping that individual states and
the federal government will offer tax credits, incentives and subsidies
to help reduce the amount of ASR ending up in landfills.
It’s not for lack of trying that a use for
ASR has not been found. Texas Industries worked with Star Recycling
to convert SR into a cement kiln fuel, but failed. Schnitzer Steel
in California, over the last 20 years, has reviewed all sorts of
ideas from direct burning to plastics recovery, but none of the
experiments has translated into a successful economic model.
“It’s very difficult in California
to site facilities that would burn ASR or to make a liquid or gas
fuel because of resulting air emissions,” said Boughton. “We
have unique barriers here.”
In Japan, where land is precious, measures are
being taken to recycle ASR.
“They do some pyrolysis and recover energy
value, and some firms are making nuggets out of the remaining soil
and glass residue,” said Boughton. “That is useful as
aggregate for road bases, but it takes a lot of energy to do it
and the economics are not that good. But when you have no landfills,
you are driven to that.”
Zmag America, Ltd., the American branch of Japan-based
Zmag Ltd., is introducing its ASR recycling technology to the North
“Our technology includes various kinds of
separation technologies,” Eishin Takahashi. “We plan
to introduce magnetic separators, stainless steel separators, non-ferrous
metal separators, and others. Zmag is considering licensing of its
technology, which has an American patent, and the sale of complete
“Licensing our solution would make sense
to customers who want to utilize their current equipment,”
said Takahashi. “The price of our systems will be different
depending on customer system configuration.”
A Zmag recycling system can recycle four tons
of ASR per hour. Approximately 10 percent of ASR consists of non-ferrous
metals, which can be sorted, sold and recycled. The remaining portion
of ASR, excluding sand and such, can be converted into fuel. Values
are determined by applying the cost of the mixed metals and the
re-sale price of ASR as fuel.
“Our technology can be used in conjunction
with other companies’ technologies such as gasification technology,”
said Takahashi. “Even for gasification, conducting thorough
recovery/separation is ideal because automobiles are made up of
various kinds of materials. The water content in the Zmag-treated
ASR was found to be stable and smaller than or equal to one-per-cent,
which is considered to be very attractive as pre-treatment of the
“Because our technology is based on thorough
separation/recovery, metal recyclers, shredding companies and metal
distributors would benefit with our technology,” he added.
“Automobile manufacturers can position themselves as a leading
player in the recycling field. In the EU and Japan, automobile recycling
legislation is already in effect.
Combined with Zmag’s ASR recycling technology,
the 95% weight wise automobile recycling rate can be achieved. Cement,
steel and paper manufacturing industries, as well as electrical
utilities, would benefit because ASR has a high heating value and
can be substituted for coal.”
For further information, visit dtsc.ca.gov/TechnologyDevelopment.