Environmental Costs of Linear Societies

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Environmental Costs of Linear Societies

• October 3, 2007

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Life Cycle Analysis of Aluminum Cans

• Americans use 102.2 BILLION aluminum cans/ year
  (368 per capita/year)
• We throw away 49.6 of these cans (50.7 billion!)
• Biggest environmental impact of this disposal is
  upstream from the consumer
• Had these cans been recycled enough energy would
  have been saved to supply gasoline to over 1
  million cars for an entire year

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Aluminum Can Production Step 1 Bauxite Mining

• Most bauxite ore from open pit or strip mines
  in Australia, Jamaica and Brazil (99 of US needs
  is imported)
• Bauxite mining results in land clearance, acid
  mine drainage, pollution of streams and erosion
• 5 tons of mine tailings (waste) produced per
  ton of bauxite ore removed
• Significant fossil fuel energy consumed in mining
  and transporting bauxite ore

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Land Degradation from mining
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For each ton of useful ore extracted, many tons
of over-burden have to be removed in the
process. For bauxite ore, the ratio can be as
high as 51.
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Mineral ores and metals are shipped all over the
world, consuming vast quantities of energy in the
process.
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Aluminum Can Production Step 2 Alumina Refining

• Bauxite ore is mixed with caustic soda, lime and
  steam to produce a sodium aluminate slurry
• Alumina is extracted from this slurry, purified
  and shipped to smelters
• Leftover slag waste contains a variety of toxic
  minerals and chemical compounds
• Alumina refining process is also fossil fuel
  energy intensive

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Refined alumina
Alumina Refining Facilities
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Aluminum Can Production Step 3 Smelting

• Powdered alumina is heated (smelted) in order to
  form aluminum alloy ingots
• Aluminum smelting uses massive amounts of
  electricity (usually from coal)
• One ton of aluminum production requires energy
  equivalent of 5 barrels of oil (210 gallons of
  gasoline)
• Aluminum smelting also produces 7.4 tons of air
  pollutants (particulate matter, sulfur oxides,
  VOCs) for every 1 ton of aluminum produced

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Aluminum Ingots
Aluminum Smelter
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Aluminum Can Production Step 4 Tertiary
Processing

• Aluminum ingots are melted (requiring more
  energy) and are extruded as sheets
• Finishing process for rolled sheets involves
  several chemicals (strong acids and bases) that
  are toxic

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Aluminum Can Production Step 5
Finishing/Assembly

• Aluminum sheet is fed into extrusion tubes and
  cut into shallow cups
• Cups are fed into ironing press where successive
  rings redraw and iron the cup. This reduces
  sidewall thickness, making a full length can
• The bottom is domed for strength
• Cans are necked in at the top and flanged to
  accept the end
• Little chemical pollution at this stage, just
  electricity use

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Aluminum Can Production Step 6
Filling/Distribution

• Cans are shipped without end portion to beverage
  company
• Beverage is injected under pressure outward
  force strengthens the can
• After filling, can is labeled and packaged
• Cardboard and plastic is used, some toxic waste
  from making paint and ink used for labels
• Finally, product in the can is trucked (diesel
  fuel use) to a wholesaler/distributor and then to
  retailer (multiple trips)

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Life Cycle Analysis of an Aluminum Can

• Mining/Extraction of Bauxite Ship to processing
  plants
• Primary Processing Convert bauxite to alumina
• Secondary Processing Convert alumina to
  aluminum ingots (smelting)
• Tertiary Processing Convert aluminum ingots
  into aluminum sheets
• Finishing/Assembly Convert aluminum sheets into
  aluminum cans
• Filling/Distribution Fill cans with beverage,
  transport to distributor/final consumers
• ALL OF THESE STAGES use significant amounts of
  fossil fuel energy. MOST OF THESE STAGES generate
  large quantities of hazardous and toxic waste
  products

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Aluminum can, used once
Steel can used once
Recycled steel can
Glass drink bottle used once
(65 less energy)
Recycled aluminum can
Recycled glass drink bottle
Refillable drink bottle, used 10 times
0
8
16
24
32
Energy (thousands of kilocalories)
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