The Case for Bauxite
Aluminum's Role in the Green Economy Transition
There is wide agreement that climate change is upon us, and the principal question is no longer whether, but how painful the consequences of alteration of our climate will be. There is also wide agreement that making the transition away from carbon intensive energy systems will require unprecedented amounts of a long list of mineral products. 
In the rush to develop these minerals, we cannot overlook the fact that minerals development in past eras has often been a source of great injustices, serious damage to the environment, and significant conflict. Frequently there is a great disconnect between those who reap great benefits from mineral development and those who experience its negative impacts. These great disparities in impacts and benefits have frequently generated social conflicts, many of them violent, which have frequently slowed or prevented mineral development – the very outcome we must seek to avoid, if accessing these ‘transition minerals’ is as important as we are being told.

Residents of 13 villages in western Guinea filed a formal complaint in 2019 against the International
Finance Corporation (IFC), the World Bank’s private-sector arm, for funding the expansion of a harmful bauxite mine.
Some of these materials are hardly household names. Others, such as aluminum, are better known, though many of us are still not entirely clear exactly where they come from, or might in the future come from, or the environmental and social costs of their production.
While there is much attention to the new, exotic materials such as rare earths, the reality is that the biggest challenge may be aluminum. Aluminum is one of the most widely produced and used metals on earth. The body of new Tesla is made mostly from aluminum, and the same can be said of many ‘energy transition’ products.
Annual global aluminum production averages roughly 65 million metric tons of primary aluminum and 30 of recycled aluminum. Today more aluminum is produced than all other non-ferrous metals combined.
 
The International Aluminum Institute expects annual global aluminum demand to nearly double by 2050, an increase of 35% and 170% in primary and recycled production respectively.
 
Aluminum is listed as a “critical mineral” by the government of the United States and a “critical material” by the European Union.The US Agency for International Development and the World Bank both recognize aluminum as both a high-impact and ‘cross-cutting’ mineral - it is used widely for both energy generation and storage technologies and is therefore critical regardless of which of these technologies are used in a given mitigation scenario.
 
Carbon Impacts of Aluminum Production
 
Finding and producing the necessary aluminum will in itself have a massive impact on carbon emissions and carbon cycles, for two principal reasons.
First, for reasons having to so with the process of ore generation, aluminum deposits tend to be located in forested tropical and semi-tropical areas (e.g., Guinea, Vietnam, Australia, Brazil, Indonesia) that currently sequester large amounts of carbon. Damaging or destroying those forests in pursuit of bauxite may liberate large quantities of the very carbon we are hoping to keep out of the atmosphere.
Alufer Bauxite Mine in Guinea
Second, producing aluminum is one of the most electrically intensive processes on earth. If we obtain aluminum by smelting it with coal based electricity, as is still the case in much of the world, it is highly questionable whether we will see the carbon reductions we need to achieve in the energy transition. Even smelting it with hydroelectricity is far from a free lunch.

Hydro Alunorte is the world's largest alumina refinery outside China and is located in the northern Brazilian state of Pará.
The alumina is the raw material for aluminum and is produced from bauxite, through the process called Bayer.

Bauxite production has additional land use impacts which can lead to significant forest loss.

Land is Needed for Storage of Wastes

So-called “Red Mud” is an industrial waste of the Bayer aluminum production process. The impacts are therefore felt where bauxite is converted to alumina.
The Bayer process produces not only the highly desired Al oxide from the bauxite ore, but it also produces an undesired by-product, called red mud. It contains toxic heavy metals and its high alkalinity makes it extremely corrosive and damaging to soil and life forms, creating a huge challenge for such disposals.
 
The rate of Red Mud production is from 0.8 - 1.8 tons of Red Mud per ton of alumina. There is therefore considerably more Red Mud than aluminum produced.

The typical “disposal” method for Red Mud used in industrial alumina operations involves discharging it as a slurry into holding ponds or dams. But the Red Mud does not “go away,” and the need to control it persists indefinitely. It is simply in a form of storage or confinement, which can ultimately fail. If red mud leaches from its storage area, whether by groundwater infiltration or large rain events, its high alkalinity and chemical components will result in impacts to water, soils, and air of the surrounding area.
Red Mud, which is both valuable and toxic is one of the biggest problems in aluminum making.
Photos after broken dyke of a reservoir containing red mud of an alumina factory, near Ajka, Hungary.

More than 150 million tons of bauxite residue are produced every year. The majority of this highly toxic (and in part also valuable) waste is deposited as landfill. Worldwide more than 100 Bayer plants are operative. The total stockpile of this bauxite residue exceeds 3500 million tons.

As much of the production is occurring in forested areas, the need for large areas of land for perpetual storage of these wastes will have an additional significant impact by reducing forest cover, and likely releasing the carbon stored in these forests to the atmosphere.

Forests are Impacted by Dust

Forests in large areas surrounding aluminum mines are demonstrably impacted by dust from mining operations. This reduces the quantity and vigor of vegetation and presumably the forest’s ability to store carbon.


Carbon Emissions from the Smelting of Alumina

It is unfortunate but true that production of a material intended to reduce greenhouse gas emissions is itself a major source of such emissions. The impacts are global in scale. The world’s aluminum smelters consume about 3.5% of the total global electric power.

Greenhouse gases within the aluminum industry represent a major environmental impact and a significant contributor to the climate crisis. Emissions from aluminum come several significant sources:

  1. combustion of fuel and electricity use for mining,
  2. industrial heat and steam, and electricity use in refining,
  3. production of other materials used in refining and smelting,
  4. fossil fuel-based electricity to power electrolytic smelting,
  5. direct CO2 emissions from electrolysis,
  6. thermal energy to generate heat and steam during fabrication,
  7. transportation to different sites for manufacturing and retail,
  8. waste processing and disposal.

As much as two thirds of total greenhouse gas emissions from primary aluminum production stem from use of electricity in smelting. The level of emissions of course depends on the type of generation used in electrical production.  Aluminum smelting requires immense amounts of electrical energy.

It seems that a considerable part of those carbon emissions come from coal powered electricity used in smelting operations. The impacts of these emissions are of global significance. Though hydroelectric power once accounted for most of the electrical energy used in aluminum smelting, coal now dominates the mix.
Hydropower Must be Evaluated on a Case by Case Basis

In most cases, hydropower is a ‘reduced carbon’ alternative for generating electrical power. However, this is not uniformly the case, especially in tropical regions, which is where most bauxite deposits are formed.

Our evaluation also must include the reality that hydroelectric impoundments tend to be large in low lying relatively flat areas, and that the are they occupy will in many cases previously been forested. Indeed, emissions from rotting inundated vegetation are at some sites the source of poor performance in greenhouse emissions.
Conclusions

There is obviously reason to be concerned about some of the other adverse impacts, biodiversity high among them.

It is not clear whether the reduction in emissions resulting from more extensive use of aluminum in renewable energy or electro-mobility applications actually results in a decrease in carbon loading in the atmosphere, given:
  • Forest areas lost to mining;
  • Forest areas lost to waste storage; and
  • The immense amount of coal being burned to generate the electricity needed to smelt alumina into aluminum.

But here we are simply looking at the question of ramping up aluminum production in terms of carbon balance.

How necessary is aluminum to the energy transition?
Can we be more efficient in its use?

Can we decrease the negative climate impacts of aluminum production?
If so, how?

If aluminum is as big a part of the energy transition as we are being told, learning how to reduce these negative impacts needs to be
at or near the top of our list of priorities.
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