Portland Aluminium uses several methods to control fluoride emissions from its aluminum smelting operations, including a fluoride recovery system, laser air monitoring, evacuation procedures, and emissions scrubbers. It works to minimize emissions through an environmental improvement program and monitors local fauna, flora, and worker exposure to ensure impacts remain low. Nearby "Smelter in the Park" acts as a buffer zone to further protect surrounding areas from gaseous emissions.

1. VCE Environmental Science
Unit 4: Area of Study 1: Pollution

2. Fluoride compounds are all related
by containing fluorine. Fluorine is a
naturally occurring element in the
earth. It is usually found in the form
of the mineral fluorspar, CaF2.
Fluorine is a yellow-green gas with
a strong, sharp odour (like pool
chlorine). It combines with
hydrogen to make hydrogen
fluoride, a colourless gas with a
strong irritating odour.

3.  Hydrogen fluoride dissolves in
water to make hydrofluoric
acid. Hydrogen fluoride will
corrode most substances
except lead, wax,
polyethylene, and platinum.
 Hydrogen fluoride is used to
manufacture other fluorine-
based chemicals including
Sodium fluoride, which is a
white powder, although
sometimes it is dyed blue for
identification purposes.

4. Hydrogen fluoride is used:
• In Aluminium production
• In Chlorofluorocarbon (CFCs) production
• In the production of aluminium fluoride, sodium
fluoride and other fluoride salts.
• Petroleum, chemical, and plastics industries.
• To separate uranium isotopes.
• To clean metals, bricks, or remove sand from
metal castings.
• To etch glass and enamel, polish glass and
galvanize iron.
• Brewing and to cloud light bulbs.

5. The primary sources of fluoride emissions
are the industries that manufacture it or
use it in production:
 Aluminium industry,
 Oil drilling and refining,
 Chemical and plastics industries,
 Agricultural and pesticide chemical
manufacturers,
 Dye manufacturers,
 Manufacturers of metal parts.
These are emissions to the air unless there
is a spill.

6.  Other possible emitters of fluoride are metal
cleaning operations, glass and enamel
manufacturing and glazing, toothpaste, and
fluoride enhanced water. These emissions may be
to the soil, water, or air.
 Fluorine is a naturally occurring element in the
earth, but elemental fluorine is too reactive to be
found in nature. Fluorine is found in nature as part
of the mineral fluorspar. Water in rivers or streams
that flow over rocks rich in fluorine-containing
minerals such as fluorspar may naturally contain
dissolved fluoride.

7.  Toothpaste, pesticides, ceramic and glass
polishing etching and frosting materials, special
dyes, drinking water in some areas may be
naturally or artificially enriched in fluoride.
Australian Drinking
Water Guidelines
(NHMRC and ARMCANZ, 1996):
Maximum of 1.5 mg/L (i.e. 0.0015 g/L).

8.  Fluorine was produced for the first time by Henri Moissan in
1886, for which he received the Nobel Prize in chemistry in
1906. The unique properties of fluorine have led to the
development of fluorine chemistry and numerous synthetic
fluorinated compounds have been prepared and tested for
different applications. The commercial use of organofluorine
compounds has grown significantly during recent years,
mainly because of increased uses in industrial,
pharmaceutical and pest-control applications. It is estimated
that the world market for fluorochemicals amounts to 11.6
billion dollars with an expected growth of 5 percent
annually. The USA is the largest fluoroorganics market,
followed by China (Baharatbook Market Research, 2004).

9.  When fluoride is emitted to the
air as a gas or particulate it
may be carried by the wind and
deposited on surrounding
vegetation and soil. The gas
dissolves in clouds, fog, rain, or
snow. This impacts the
environment as wet acid
deposition ('acid rain'). In the
environment it will react with
other chemicals present
(ammonia, magnesium,
calcium) to form salts,
neutralising the acid.

10.  Industrial emissions of fluoride
compounds can produce
elevated concentrations in the
atmosphere. Hydrogen fluoride
will exist as a particle, which may
dissolve in clouds, fog, rain, dew,
or snow. In clouds and moist air it
will travel along the air currents
until it is deposited as wet acid
deposition (acid rain, acid fog,
etc). In waterways it readily
mixes with the water.

11.  “The substitution of HCFC’s and other chemicals for
hydrofluorocarbons and the increased growth in
fluorinated refrigerants and coatings will boost the
demand for fluorochemicals in the coming years. Much
of the usefulness of organofluorine compounds rests in
their chemical stability and recalcitrance to biological
degradation. Of all types of bonds in organic chemistry,
the carbon-fluorine bond is the most inert and resistant
to cleavage (Hiyama, 2000). Given the chemical
inertness of fluorinated organics, their bioactivity
persistence, it is important to understand their
environmental fate and the mechanisms by which they
can be degraded.”

13. Workers in the industries that use or
produce fluoride compounds are at
greatest risk of exposure.
Consumers are most likely to be
exposed to fluoride compounds when
using consumer products containing
fluoride compounds; especially
toothpaste or fluoride enhanced water.
Residents in close proximity to
production and processing facilities
using fluoride compounds may also
receive very low levels of fluoride
exposure.

14.  Fluorides are everywhere
throughout the environment,
but at very low levels that are
not believed to be harmful.
 Small amounts of sodium
fluoride help prevent tooth
decay, but high levels may
harm your health.
 In children whose teeth are
forming, excessive fluoride
levels may cause dental
fluorosis with visible changes
in the teeth.

15.  High levels of fluorine or hydrogen fluoride gas
can cause muscle spasms, harm the lungs and
heart and cause death. At low levels they can
irritate the eyes, skin and lungs.
 Contact with hydrofluoric acid (even diluted)
can burn the eyes (causing blindness) and skin,
causing severe burns deep beneath the skin
damaging internal tissues. This can occur hours
after contact, even if no pain is initially felt.
 Contact with hydrofluoric acid happens mainly in
the workplace. Long-term exposures may
damage the kidneys and liver.

17. In adults, high fluoride
over a long time may
lead to skeletal fluorosis
with denser bones, joint
pain, and limited joint
movement. This is rare
in developed countries,
but many people in India
and Africa may be
affected.

18. Hydrogen fluoride will exist as a particle in the air if released
to the atmosphere. It dissolves when mixed with water.
Insufficient data are available to predict the short-term or
long term effects of hydrogen fluoride to aquatic life, plants,
birds or land animals. Concentrated hydrogen fluoride is
very corrosive and would badly burn any plants, birds or
land animals exposed to it. The concentrations of hydrogen
fluoride found in close proximity to sources may adversely
affect some species of plants. Small quantities of hydrogen
fluoride will be neutralised by the natural alkalinity in aquatic
systems. Larger quantities may lower the pH for extended
periods of time. Fluorides are not expected to bio-
accumulate.

19.  “Both Point Henry and Portland
Aluminium smelters continue to
focus on minimising and
sustaining fluoride emissions
within internal (Alcoa) targets,
which is reflected in the long-term
historical trends (see graph).
Alcoa’s internal targets are more
stringent than those set by the
Victorian Environmental Protection
Authority.”
http://www.alcoa.com/australia/en/inf
o_page/environ_air.asp

20.  “Portland Aluminium continues to
progress a long-term
management program for fluoride
emissions, to further understand
and manage the effects of low
level fluoride emissions on local
fauna inhabiting the land
surrounding the smelter. Fluoride
emissions were sustained at
around 0.3kg/tonne of aluminium
produced in 2009, making
Portland Aluminium one of the
lowest fluoride-emitting smelters
in the world.”

22.  The Portland Aluminium smelter is situated
on 600 hectares of land, 500 of which form
“Smelter in the Park”, a once-barren area that
has been revegetated with a large variety of
indigenous plants. This area forms a buffer
zone, that protects surrounding residents
from the full impact of gaseous emissions
from the smelter. There are five monitoring
stations at different locations around the
smelter that provide data on fluoride and
sulfur emissions on a regular basis. Portland
Aluminium also routinely test their workers,
using urine and blood tests, as well as
exposure badges, which monitor the levels of
fluoride that staff have been subjected to.

23. Environmental scientists also do
water testing and take tail-bone
samples of the local kangaroos and
teeth, bone and horn samples of the
beef cattle , to test for long-term
fluoride exposure. An international
botany expert visits annually to
check for signs that toxic emissions
may be affecting local vegetation.
Signs of fluoride exposure include
yellowing and curling of leaves and
tissue death.

24.  Inthe potrooms, the major point source of
fluoride emissions, Portland Aluminium have
laser air monitoring of gaseous fluoride, with
a traffic light system – green, amber and red.
Between 045ppb and 600ppb, the lights are
green; between 600ppb and 800ppb the lights
are amber and above 800ppb the lights are
red, which indicates an error in the process –
too many hoods open at the same time.

25. Portland Aluminium use several methods to prevent
excessive fluoride emissions, including the A398 fluoride
recovery system, in which fluoride emissions are captured
from the hooded aluminium pots and forced through a
conveyor of alumina, to form reacted or fluoride-enriched
alumina. This is then added to the pots, which reduces the
temperature (and therefor the energy required) to obtain the
pure aluminium. The particulate and gaseous emissions are
filtered through huge canvas bags, also coated with
alumina, which traps 98% of fluoride.
When the laser monitoring systems indicate excess fluoride
levels, staff will be evacuated to prevent critical exposure.

26.  Research-Cottrell is the exclusive worldwide licensee for Alcoa's A-398
and A-446 fluidized bed dry scrubbing technologies. The technologies
provide emission control and fluoride recovery from both primary
aluminum potline and bake oven applications.
 A-398 systems are currently installed on more than 20 smelters (56
potlines) worldwide, treating over 20 million cfm of potroom gases from
both prebake and reduction cells.
 The A-398 and A-446 technologies routinely achieve greater than
99.9% fluoride removal efficiencies. In addition to controlling fluorides
and particulate, the A-446 scrubbing process significantly reduces
hydrocarbons (Tars, POM, B(a)P) and SO2 emissions from bakeoven
furnaces, without a separate spray cooling chamber.
 The systems combine fluid bed scrubbers with air pollution controls
such as fabric filters, electrostatic precipitators, wet and dry scrubber’s
and VOC-removal technologies, to reduce emissions.
 http://www.tms.org/Meetings/Annual-98/Exhibitors/ResearchCott.html

27.  “Bacterial Degradation of Fluorinated
Compounds”
http://dissertations.ub.rug.nl/faculties/scien
ce/2007/m.i.m.ferreira/?pLanguage=en&pF
ullItemRecord=ON
 “Portland Aluminium EIP”
http://www.alcoa.com/australia/en/info_pag
e/environ_air.asp