PRIMARY AND SECONDARY PRODUCTION
the primary producers, we can clearly
observe that Chinese producers outnumbered the producers from other countries.
All the leading aluminum producing companies mentioned in Table 2 are private groups except The Aluminum
Corporation of China Ltd (Chalco) 17.
MAJOR PRODUCING COMPANIES
UC Rusal (private)
Rio Tinto Alcan
The United States
Tab 2. The world’s leading primary aluminium producing companies in 2016, based on
production output (in million metric tons) 18.
Secondary Production is the recycling
process of aluminium scrap into aluminium that can be used again—an
environmentally beneficial process that is 92 % more energy efficient than
primary production. The increased proportion of recycled aluminium in manufacturing has created
significant economic and environmental wins for both industry and consumers. Approximately
40 percent of the North American aluminium
supply is now created through secondary production, up around 10 percent since
the early 1990s. 19 As it is shown in
figure 4, Brazil has the highest rate secondary production as 98.2% of its can
production are recovered by recycling 21. In the figure (above) we can
observe the production capacity of secondary aluminium
producers. Novelis company’s Brazil branch is leading as they can reach up to
600000 tonnes of recycled aluminium per
year. Generally, Chinese aluminium
manufacturers show considerable numbers both in primary and secondary
Fig 4. The world’s leading secondary aluminium producing companies, with production
capacity up to 2017 (tonnes per year) 20.
Secondary aluminium production accounts for nearly 30% of the global aluminium output and its share keeps growing (Figure
Fig 5. Comparison of primary and secondary aluminium production by the percentage by the year of 2013 23.
In a resource-constrained world, recycling is a critical point to consider in sustainable development. It reduces
the waste and maintains the saving of the resources. Aluminium in use-recyclable
aluminium is an energy and resource bank,
but because of the long lifespan of many aluminium
products, and due to growing demand, this “bank” can only supply 20-25 % of the
current demand. The remainder must be produced through primary aluminium 24.
3.3. PRODUCTION CHAIN (MINE TO MARKET)
Production of Aluminum from ore is mainly
dependent on Aluminum oxide (Al2O3), which is extracted from bauxite ore. Normally
bauxite contains from 30% to 60% Aluminum oxide (which is called also alumina)
and it is easy to be found near the earth’s surface. The process can be divided
into two parts; the extraction of alumina from bauxite, and the smelting of
Aluminum metal from alumina. Separation of alumina generally is done by the
Bayer Process. This process involves crushing the bauxite into a powder, making
a slurry by mixing it with water, heating
and adding caustic soda (NaOH). The caustic soda is added to dissolve alumina
and allow it to pass through filters, which leaves
The solution of aluminate is then
drained into precipitator tanks where particles of Aluminum hydroxide are added
as ‘seed’. Agitation and cooling result in Aluminum hydroxide precipitating
onto the seed material, which is then heated and dried to produce alumina.
Electrolytic cells are used to smelt Aluminum from alumina in the process which
is discovered by Charles Martin Hall.
fed into the cells is dissolved in a fluorinated bath of molten cryolite at
1742F° (950C°). A direct current of anywhere from 10,000-300,000A is sent from
the carbon anodes in the cell through the mixture to a cathode shell. This
electrical current break down the alumina into
aluminium and oxygen. The Aluminium is
attracted to the carbon cathode cell lining when the oxygen reacts with the
carbon to produce carbon dioxide.
is collected and taken to furnaces where recyclable aluminium materials can be added. About 1/3 of all aluminium produced today comes from recycled
3.4. ENVIRONMENTAL AND SOCIAL
IMPACTS OF PRODUCTION
There are environmental impacts that associated
with each stage of Aluminium production from
extraction to processing. One of the major environmental impacts of refining and smelting is greenhouse gas emissions. The
greenhouse gases result from both the electrical consumption of smelters and
the by-products of processing. The greenhouse gases resulting from primary
production include perfluorocarbons (PFC), Sulphur dioxide (S02), polycyclic
aromatic hydrocarbon (PAH), fluoride, and carbon dioxide (CO2). Of these gases,
PFC’s resulting from the smelting process are the most effective. In the US, primary
Aluminum production is the main source of perfluorocarbon(PFC) emissions. PAH
emissions result from the manufacture of anodes for smelters and during the
electrolytic process. Sulphur dioxide and sodium fluoride are emitted from
smelters and electrical plants. SO2 is one of the primary reasons of acid rain.
CO2 emissions can occur during smelting and result from the consumption of
carbon anodes and from PFC emissions.
atmospheric pollutants from primary Aluminum production also produce acid rain
when they mix with vapor of water. When soil pH remains at or above 5.0,
Aluminum poses no danger of toxicity for environmental, however acid rain
lowers the pH of soil and forces Aluminum into solution which causes it to leak
into the water supply where it can damage root systems and create acidified
lakes. The amount of Aluminum that enters the environment due to regular
weather processes far exceeds anthropogenic contributions.
A life cycle analysis of Aluminum
shows distinct advantages to recycling the material. The primary benefit of
recycling Aluminum is reduced energy consumption. Aluminum recovery from scrap
requires only 5 percent of the energy required to extract it. Therefore, secondary
Aluminum production from recycling scrap has the potential to significantly
reduce greenhouse gas emissions. The most common source of Aluminum scrap is
Aluminum cans, but automobiles, building materials, and appliances are also
viable sources. Repeated recycling of Aluminum does not affect the quality.
Substantial amounts of Aluminum can be toxic to humans, but high exposure
levels are typically limited to miners, Aluminum production workers, and
dialysis patients. While there is some evidence linking Aluminum to Alzheimer’s
disease, increased Aluminum consumption has yet to be a proven cause of the
onset of Alzheimer’s. Otherwise, Aluminum is not significantly bioaccumulated
in plants and animals #26. Some groups may be adversely affected by the
activities, such as involuntary resettlement, loss of land for harvesting and
impacts on traditional ways of life. The presence of a production plant or mine
may also enlarge the economic gaps between groups of people, and generate
social tensions 27.
3.5. RED MUD DISPOSAL
Red mud is one of the major
environmental impacts of Aluminium comes
from the primary production through the refinery process. It has a high content of alkalinity. In early days the
red mud was simply dumped into the rivers or the nearby sea. Because of the
inefficient washing of the red mud, it
contained a substantial amount of Na2O. Despite today’s efficient
washing process, red mud is deposited as
landfill. It shows no severe environmental hazard, but it requires a large area of
the red mud lake. Also, according to the European List of Waste, the red mud
resulting from the alumina refining process is classified as a non-hazardous
waste 28, 29.
3.6 SUSTAINABILITY POLICY OF ALUMINUM PRODUCING
Overall, there is
a global trend towards the protection of
the environment by the industry. The main
driving force behind the environmental
policies is coming from European authorities.
agreement with the European legislation on industrial emissions, the BREF (BAT
reference documents) chapter for the aluminium
industry is describing the Best Available Techniques (BAT), and the related
performance, which is base conditions for environmental permits for primary and
secondary (recycling) aluminium
production sites. European Aluminium manufacturers are actively participating
in the development of this document, with the objective to combine an ambitious
environmental protection with the technical and economic feasibility. 30.
Since 1990, the European aluminium industry has reduced its CO2
emissions by half and Perfluorocarbon (PFC) emissions by 90%. The target is to
further reduce industrial energy consumption by 10% per tonne of aluminium produced or transformed. One of the main
concerns in the Aluminum industry is energy
efficiency, and about 40% of the costs of primary aluminium producers in Europe comes from electricity. As base-load
consumers, aluminium producers assist the
balancing of the grid and the use of renewable energy sources 31.
producing companies such as Hydro (Norway) are committed to reducing the greenhouse gas emission by
creating more “green energy”. About two-thirds of the electricity used in
primary production is already from renewable sources, and it is intended to use
this as a platform for developing more renewable sources around the world.
Producing more and emitting less
will lead to increased production output
while reducing energy consumption. Recycling more Aluminum is another solution
as it requires only 5 percent of the energy used for primary production, thus saving both energy
and greenhouse gas emissions. 32
Life Cycle Assessment (LCA) provides
the best framework for assessing the potential environmental impacts of
products including raw material acquisition, fabrication, transportation, use, and end-of-life.
industry is a dedicated supporter of LCAs and advocates for them to cover the
full lifecycle of products, i.e. including environmental loads and benefits of
end-of-life recycling that reflect the true value of recyclability.
To facilitate LCAs, the aluminium industry publishes environmental
impact indicators for its main processes, from mining, alumina refining and
electrolysis, extrusion, rolling, recycling and developed LCA models for cars
and several building products according to European and International standards.
industry is involved in LCA-based methodologies developed by the European
Commission like the Product Environmental Footprint 33.