| DENSE MEDIUM SEPARATION: METALS | COAL PLASTIC AGRICULTURE |
Automobile and Industrial Waste - ASR
Since 1991, ESR
International LLC has applied its bi-directional dense
medium separation technology to the recycling of automobile
and industrial waste. For many years ESR’s principle client
in this regard has been the Galloo Group. At first the
Galloo staff was not convinced that a carrot separator
could compete with the classical dense medium separators on
the market at that time. So they set up a trial on <12mm
automobile shredder residue, running half of the test
material through a conventional Wemco drum and the other
half through this modified carrot separator.
The results here were quite
dramatic: the Wemco drum showed 15% misplaced material
(either floats in sinks or sinks in floats), whereas the
ESR separator showed less than 0.1% misplaced material.
Since the ESR drum was approximately 150 times more
accurate than the Wemco drum, Galloo never looked back.
This aggressive and forward-looking company went on to set
up four of the largest and most profitable recycling
centers in the world: one at Halluin (France), two in Menen
(Belgium), and a final one near Charleroi (Belgium).
The
Inefficiency of Eddy Current Separators
The best technology at the
time in Europe for separating non-ferrous metals was the
eddy current separator. But an eddy current separator even
to this day is extremely inaccurate, and even after
multiple passes, it typically leaves behind an organic
reject of a non-ferrous metal content as high as 15%.
At this point, the Galloo
Group saw a huge opportunity and negotiated with over 30
shredder operators in Belgium, Holland, Germany and France
to process and dispose of their eddy current reject. The
Galloo Group was actually paid to take this so-called waste
material, and on one particular site in France, Galloo was
extracting as much as 40 tons per hour of non-ferrous
metals at a face value of over $1,000 US dollars per ton,
all from material destined for landfill. This 40 tons per
hour of non-ferrous metals represents roughly the metals
from over 750 automobiles per hour.
In this revolutionary metal
sorting process, the suspension fines needed to change the
density of water for all separations below a density of 1.6
are obtained nowhere else but from the ultra-fine inorganic
metals and glass generated in abundance by hammer-mill
shredding. Two stages of classifying cyclones isolate these
fines from the scrubbing and sizing barrel situated at the
beginning of the process.
Since all of the waste in a
dense medium process is introduced into water, ESR took the
logical step in 1997 of introducing a 1.0 separator as the
first separation in a series of separations. In this way,
the costly and inefficient air separation technology
generally associated with the processing of automobile
shredder residue is no longer required. The 1.0 separator
isolates foam rubber, wood, textile and plastics less than
1.0 in density. Other technologies separate these four
products from one another. Foam rubber is easily re-bonded
to make a variety of automotive insulation products.
After the 1.0 separation,
the next separation usually takes place at a density of
about 1.6. This separates organic from inorganic. The
floats of the 1.6 separator report to another separator at
a 1.25 density. The sinks of this 1.25 separator represent
an organic rich in PVC, a fraction ideal for those
technologies such as the Vinyloop process that recovers PVC
by means of solvents. The floats of the 1.25 separators can
be routed to a 1.10 separator, and the floats of this
separator represent a plastic that can be blended and
pelletized and used for the fabrication of new plastic
components.
All of these attempts to
recycle plastic as plastic easily fall short, and the
residues from these processes, together with rubber, can be
used as an alternative fuel in cement kilns or as a
reductant and fuel in blast furnaces or electric arc
furnaces. For over 10 years the floats of the 1.25
separator were supplied to cement kilns in Belgium and
France. This greatly reduced the amount of fossil fuel
needed to make cement, and in burning this alternative
fuel, these cement kilns were able, at times, to make
cement at a negative energy cost. The ash from the burning
of this alternative fuel is vitrified and becomes part of
the finished product. Even the slag from an electric arc
furnace can be disposed of in a cement kiln and actually
enhances the cement-making process, as in the CemStar
process patented by Texas Industries (TXI) and marketed by
Hatch of Canada. It is hard to imagine a landfill avoidance
strategy that does not work closely in conjunction with the
steel and cement industries.
The sinks of the 1.6 then
report to the 3.2 separator, isolating a broad range of
heavy metals such as: zamac (6.6sg), zinc (7.1sg),
stainless steel (8.5sg), nickel (8.8sg), copper (8.9sg),
and lead (11.3sg). Galloo in Belgium boasts of a heavy
metal fraction containing less than 0.1% aluminum. By means
of sizing screens and eddy current separators, most of the
copper can be removed from this heavy metal fraction.
Copper constitutes as much as 1% of the weight of an
automobile, and with ESR technology, all of this valuable
metal is recovered. This stands in sharp contrast to eddy
current separators which miss most of copper present in
automobile and industrial waste.
The floats of the 3.2
separator report to the 2.2 separator, which separates
magnesium (1.7sg) from aluminum (2.7sg). The maximum
allowable magnesium in aluminum is 0.4%. The actual
magnesium after ESR separation stands at 0.1%. But even
this is not a separation error: it represents unliberated
or alloyed magnesium which in theory cannot be separated.
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| 1.25 Separator at Galloo Recyval near Charleroi, Belgium | 1.0 Separator at CFF Recycling, Bruyere-sur-Oise, France |
During the summer of 1997, ESR set up a large recycling center at Chaparral Steel in Midlothian, Texas., and during the summer of 2004, ESR set up another recycling center at Bruyere-sur-Oise, France, with CFF Recycling, the largest recycling company in Western Europe.