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How
One Packaging Manufacturer Handles Environmental
Requirements & Safety Issues
By
William R. Rusch, President
Anodizing,
the electrochemical oxidation of aluminum,
is widely used throughout the world for
a variety of functional and decorative applications.
In anodizing, a thin film of aluminum oxide
forms on the surface of the aluminum part
and acts as a barrier against further natural
oxidation or corrosion.
Before it is anodized, the aluminum is treated
in a variety of chemical baths to yield
a bright, semibright, or matte surface finish.
Then the prepared aluminum surface enters
the anodizing bath, where a sulfuric acid
electrolyte is present with a low-voltage
DC charge, resulting in an electrolytic
reaction and the formation of the oxide
layer. This film subsequently can be colored
using aqueous dyestuffs that are absorbed
into the porous structure, and then finally
sealed in boiling deionized water. The result
is a decorative and durable finish. Anodizing
is scratch-resistant and will not flake,
peel, or fade and is suitable for high-speed
bowl feeding applications.
Anodizing has been called the “green,”
or environmentally friendly, finish in the
metal finishing field for some time. The
process releases few toxins into the environment,
uses almost no heavy metals, and uses chemicals
and metals that are recycled easily. Finished
products made from anodized aluminum are
nontoxic and safe to use in many packaging
applications for consumer products, including
cosmetics and beverages.
Over the past several decades, cosmetics
container manufacturers have significantly
reduced the use of buff and lacquered finishes,
which produce solvent emissions as a byproduct,
or plated finishes, which utilize heavy
metals and have residual hazardous wastes,
and changed to anodized aluminum finishes.
Nearly all major cosmetics packaging manufacturers
routinely use anodized finishes in their
metal packaging applications.
Anomatic
Corp. is one such container manufacturer.
The anodized aluminum components it designs
and manufactures are for packaging fragrance
and lotion pumps, treatment caps and closures,
mascaras, lipsticks, and eyeliner pencils,
to name a few.
The company’s core philosophy is that
manufacturing products at the expense of
harming the environment is not acceptable.
In line with this philosophy, the company
has made a significant, long-term commitment
to protect the environment through state-of-the-art
waste treatment and recycling processes.
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Selecting
Aluminum
The manufacture of an anodized aluminum component
at Anomatic begins with the choice of base
metal and alloy. Aluminum is the most commercially
recyclable metal used today. Because recycled
aluminum is already in the metallic state,
all of the energy spent purifying the ore
and reducing it to metal is saved when it
is recycled. Simply melting the aluminum renders
it usable again. All scrap parts at Anomatic
(rejects for visual or dimensional nonconformance)
are sent to local recycling facilities. In
addition, the aluminum trim that comes off
the stamping operation also is sent out for
recycling.
While most products the company produces are
made with conventional base alloys such as
5657 and 9020, some cosmetics packaging manufacturers
have begun to specify recycled aluminum alloys
such as 3004. Anomatic is participating in
this initiative. Caution is warranted because
recycled aluminum can contain heavy metals,
particularly lead and cadmium. Heavy metals
are a concern because the preanodizing finish
steps entail metal removal, so these metals
can end up in the wastewater discharge. The
Coalition of Northeastern Governors (CONEG)
limits are 100 parts per million (PPM) for
the total of listed metals. Many of the recycled
alloys have higher concentrations of the listed
metals resulting from poor segregation of
heavy metal sources from the aluminum scrap.
However, with proper selection criteria, the
recycled alloy can be used in conformance
with CONEG limits.
Stamping and Degreasing
The fabrication step involves deep drawing
aluminum coil stock into various shapes and
sizes using high-speed transfer presses. The
stamping oils are easily captured and reused.
Oil-laden scrap is spun through a centrifugal
chip wringer, and then the clean scrap is
sent out for recycling while the oil is reused
in the presses.
The stamped products go through aqueous degreasers,
where the oils are captured through ultra
filtration and coalescing filters, then sent
to a fuels blending program. Because no solvents
of any kind are used in the degreasing operation,
the captured stamping oils are non-hazardous
and easily blended into fuel oil. The stamping
and degreasing processes produce no emissions
or hazardous waste.
Anodizing
Several inorganic acids (nitric, sulfuric,
and phosphoric) are used in the anodizing
process. The acids are rinsed from the aluminum
parts between the process steps to prevent
bath contamination. Aluminum metal is dissolved
in these acid baths.
The acidic rinse water must be treated before
being discharged to the local wastewater treatment
plant. Solids are removed using conventional
hydroxide precipitation followed by clarification
and filtration. The filter press produces
a solid cake of aluminum hydroxide that is
nonhazardous waste and is sent to a landfill.
The clarified rinse water is neutralized and
sent to the sanitary sewer system.
All effluent leaving the company is monitored
using a continuous-sampling device that operates
24 hours a day, 365 days a year. An on-site,
EPA-certified chemical laboratory that uses
wet chemistry analysis and metals testing
equipment is staffed by trained technicians
during production hours. Effluent purity test
results are shared daily with the local wastewater
treatment facility.
Nickel is the one regulated heavy metal used
in Anomatic’s anodizing process. The
nickel comes from the dilute solution of nickel
acetate used in the sealing process, in which
the anodic pore is closed (sealed) through
hydrolysis. The rinse water from the sealing
step is segregated and put through a separate
nickel treatment system. The nickel metal
is removed from the effluent through metal
hydroxide precipitation followed by clarification
and filtration. The resulting cake of nickel
hydroxide is sent off-site to a nickel smelter
for recycling. This anodizing process produces
no residual hazardous wastes.
Finally, all acidic air emissions are captured
and thoroughly cleaned by scrubbing systems,
which are permitted and tested routinely by
the Ohio EPA. Nitrous oxide (NOx) gases produced
by the chemical brightening baths are chemically
converted to nitrogen gas and water vapor.
Acid gases are neutralized and odors eliminated
through multistage packed tower scrubbers
using high-pH caustic absorption.
Recycling
In addition to its efforts in recycling aluminum,
stamping oils, and nickel metal, the company
also has sophisticated processes and programs
for recycling phosphoric acid and titanium
scrap.
Its phosphoric acid recycling system uses
ion exchange and vacuum separation equipment
to purify and reuse phosphoric acid water
segregated at the anodizing lines. More than
85 percent of all the phosphoric acid is recycled,
thereby preventing large-scale phosphate contamination
of downstream water systems.
Titanium is used in Anomatic’s proprietary
conveyor belt system and in its anodizing
racks. As belts and racks wear out over time,
the titanium scrap is captured and sold back
to the titanium mills for reuse.
Safety Issues
Anomatic’s anodizing process contains
none of the regulated heavy metals (chromium
VI, lead, mercury, cadmium, barium, arsenic,
and selenium) as outlined by Z66.1-1964 (toy
safety regulations), 16 CFR 1303 Consumer
Product Safety Commission, ASTM F 963 (consumer
safety specifications on toy safety), CONEG
Heavy Metals Legislation, and Proposition
65.
The only heavy metals the company uses are
nickel II (used in the sealing process) and
chromium III (dyestuffs). The nickel hydroxide
in the anodic coating is in microscopic concentrations
and is either chemically bound to the anodic
pore or precipitated inside the pores. It
is stable both chemically and physically,
and it is insoluble in water so it cannot
be dissolved. Trivalent chromium is a naturally
occurring form of chromium that is an essential
element in our diets and is present in vitamin
supplements. The chromium in the dyes used
at Anomatic contains chromium III, not the
toxic chromium IV. The chromium III dyes generally
are regarded as safe and are completely sealed
inside the anodized aluminum coating, preventing
contact or degradation.
William Rusch, President of Anomatic Corp
1650 Tamarack Road,
Newark, OH 43055,
740-522-2203, fax 740-522-3339
info@anomatic.com.
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