Presentation 7 in a series for VCE Environmental Science

1. VCE Environmental Science:
Unit 4: Pollution
Fluoride Mitigation Strategies at
Portland Aluminium
An evaluation of the strategies used
to reduce fluoride pollution emitted
by the “Smelter in the Park”.

3. EPA Licensing of Fluoride Emissions
• Portland Aluminium has an EPA Licence outlining emission
limits for fluoride. These limits are set to ensure that the
design criteria are met where people may be exposed.
• Fluoride is measured inside the facility’s emission points (or
stacks) and reported annually to EPA Victoria.
• Licence limits set out in EPA licences require emissions to
be well within safe levels. This means that concentrations
of fluoride in air around industrial facilities meet the levels
that have been set to protect vegetation and grazing
animals and therefore human health.

4. Covered electrolysis pots for smelting aluminium.

5. Inside Monitoring
• Workers are asked to submit blood and urine
samples on a regular basis to test for fluoride
absorption.
• A monitoring badge may be worn to test
daily exposure rates.
• Laser-light monitoring in the pot-rooms
shows green-amber-red lights for different
levels of fluoride emissions (measured in
parts per billion).
• If the level reaches the critical ‘red’ amount,
alarms sound and workers are evacuated
form the pot rooms. This only happens when
smelter workers have not followed correct
procedures and opened too many pots at
one time.

6. Diagram of an Aluminium Smelting Pot

7. “FLUORIDE DISPERSION IN A COASTAL
ENVIRONMENT” John Hill and Peter Hurley
• “Gaseous and particulate fluorides emitted from the potroom roof
vents have the potential to injure vegetation and degrade
ecosystem health. Fluoride dispersal is monitored within the heath,
adjacent farmland and the city area.”
• “A continuous air monitoring station is maintained to the north of
the smelter and supplemented with a network of rainfall
monitoring sites.”
• “An updated model of fluoride dispersal using The Air Pollution
Model (TAPM) was prepared to enable a review of the current
monitoring program.”
• “Preliminary modelling of gaseous fluoride did not show good
correlation with monitoring data until exponential decay was
incorporated into the model (that is fluoride was progressively
removed using an arbitrary time-based factor).”
• “This was rationalised on the basis of the reactivity of gaseous
fluoride and the high aerosol load in coastal air.”

8. Atmospheric Monitoring
• There are many external atmospheric monitors
that measure fugitive emissions from the pot
rooms.
• These are located at different distances and
compass points around the pot room buildings to
measure fluoride (and other pollutants) during
varying environmental conditions (temperature,
wind speed and direction, precipitation and
humidity will all effect these levels).

9. Monitoring water quality at Portland Aluminium

10. Environmental Monitoring - Animals
• Bone, tooth and horn samples are taken from the cattle
that graze within the smelter boundaries, to test for
fluorosis.
• Kangaroos have been affected in the past, so tail bone
samples are also taken from kangaroos that have died in
the area.
• Fluoride tends to replace calcium in bone and tooth enamel
causing discolouration and thickening.
• Vegetation and grazing animals are more sensitive to
fluoride than humans.
• Industry Licence limits set by EPA Victoria require emissions
to be well within safe levels for vegetation and grazing
animals. Therefore, human health is also protected.

11. Kangaroos and cattle have teeth and
bone samples tested for fluorosis.

12. Environmental Monitoring - Plants
• In the 600 hectares of land surrounding the
smelter, which acts as a buffer zone between the
point source of emissions and residential
properties, a great variety of vegetation has been
planted.
• Because plants are sensitive to fluoride
emissions, it is likely that they will show the first
impacts of excessive fluoride pollution.
• Each year an expert botanist visits to take plant
surveys to check for chlorosis (damage to leaf
chlorophyll causing plants to turn yellow).

13. • Fluoride compounds, which occur as both gases
and aerosol, cause damage to plants at
concentrations about 1000 times lower than
those that cause detectable human health
effects. Certain plants, such as grapevines, are
particularly sensitive. The Australia and New
Zealand Environment Conservation Council has
recommended environmental guidelines (based
on damage to plants) for fluorides (ANZECC 1990)
http://www.environment.gov.au/soe/2001/publications/theme-
reports/atmosphere/atmosphere05-9.html

15. Fluoride levels in the bones of some kangaroos near Portland Aluminium have
been above desirable concentrations. The problem may be compounded by
fluoride present in some fertilisers used in the region. Significant reductions in
fluoride emissions from the refinery have been achieved recently through
modifications to refining methods and improved pollution. There have been
consistently low atmospheric fluoride concentrations near the Alcoa smelters in
Victoria since 1993.

16. Monitor – Plan – Implement - Check
• All the effective monitoring is of no use unless
a plan to reduce emissions has been prepared
and implemented.
• Portland Aluminium’s plan includes the A398
fluoride recovery system, which recovers
99.8% of fluoride emissions from the pot
rooms.
• Recovery and recycling of Spent Pot Lining
also reduces the fluoride emissions.

17. General arrangement of Fluoride recovery process.

18. A398 Fluoride Recovery System
• The covered pots reduce the amount of particulates and
gaseous emissions that escape into the pot rooms.
• The gases produced during electolysis are trapped and then
piped to the A398 Recovery System which consists of a bed
of fluidized alumina, which traps the fluoride emissions as
they are pumped through from underneath the conveyor.
• The fluoride-rich alumina is then conveyed to the smelting
pots.
• Fluoride helps to lower the melting point of the alumina so
that less energy is required to produce molten aluminium.
• Less fluoride inputs are required as the about 99.8% of the
fluoride is recycled in this manner.

19. Bank of A398 Fluoride Scrubbers

20. Portland Aluminium has the lowest fluoride emissions of
any of the six primary aluminium smelters in Australia,
according to the Australian Government “State of the
Environment” report (2001). (120 tonnes/year)
http://www.environment.gov.au/soe/2001/publications/t
heme-reports/atmosphere/atmosphere05-9.html

21. Alcoa Portland Plant Total Fluoride
(Portland Internal Limit = 0.63 in kgF/tonneAl)
(EPA limit = 418 gF/min)

22. Environmental Improvement Report
• The Point Henry and Portland Aluminium smelters are
working to reduce anode effects which produce
perfluorocarbon emissions.
• Anode effects are caused by low alumina levels in
smelting pots and are a main source of direct
greenhouse gas emissions from aluminium smelting.
•Point Henry has seen a 55% reduction in PFC
emissions since 2005, while Portland Aluminium has
seen a 75% reduction since 2005.
http://www.alcoa.com/australia/en/pdf/Sustainability_Re
port_2009_Final.pdf

23. Reducing Fluoride Pollution

24. Lowest Fluoride Emissions
• During 2009, both Point Henry and Portland Aluminium
smelters continued to focus on minimising and sustaining
fluoride emissions within internal (Alcoa) targets, which is
reflected in the long-term historical trends.
• Alcoa’s internal targets are more stringent than those set by
the Victorian Environmental Protection Authority.
• Portland Aluminium continued to progress a long-term
management program for fluoride emissions in 2009, 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, making Portland Aluminium one of
the lowest fluoride-emitting smelters in the world.

26. Sustainability Goals
Through the “Sustainability Strategic Framework”, Alcoa set itself some
challenging goals, including:
• Zero fatalities and lost work day or recordable injuries.
• 25% reduction in greenhouse gas emissions by 2010, compared to the
base year of 1990.
• 10% reduction in energy intensity by 2010, compared to 2000.
• 70% reduction in process water use by 2010, compared to 2000.
• 50% of Alcoa‟s fabricated aluminium output produced from recycled
metal by 2020.
• 40% of Alcoa employees contributing to their communities through
volunteering.

28. REFERENCES
• http://www.alcoa.com/australia/en/alcoa_austral
ia/location_overview/portland.asp
• http://www.alcoa.com/australia/en/pdf/Sustaina
bility_Report_2009_Final.pdf
• http://www.environment.gov.au/soe/2001/publi
cations/theme-
reports/atmosphere/atmosphere05-9.html
• http://aluminium.org.au/australian-
aluminium/aluminium-portland
• http://www.health.vic.gov.au/environment/down
loads/fluor_air.pdf