Bauxite Residue Storage Efficiency
Bauxite Residue Storage Efficiency

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Landfilled Waste
Landfilled Waste

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Alumina Refining

 

Minimizing Our Environmental Footprint

 

Innovation and commitment are behind the significant progress we have made in lessening our impact on the environment.

 

We closely manage the emissions and waste we generate and continually look to eliminate them at their source, effectively control them in compliance with applicable laws, or find alternative uses for them. Challenges remain, especially with bauxite residue and mercury emissions, but we remain committed to developing and pursuing technologies and processes that continue to shrink our footprint.

 

Bauxite Residue

Bauxite residue is generated during the alumina refining process and is composed of coarse sand and mud, along with some residual caustic soda. It is stored in impoundments called residue storage areas that are capped and re-vegetated when full. In 2014, we generated 26.4 million metric tons of this residue.

 

We have three long-term strategic targets for bauxite residue that are focused on reducing the overall footprint associated with our management of the material. These goals are:

  • From a 2005 baseline, a 15% reduction in bauxite residue land requirements per unit of alumina produced by 2020; 30% by 2030;
  • Rehabilitate 30% of total bauxite residue storage area by 2020; 40% by 2030; and
  • Reuse 15% of bauxite residue generated by 2020; 30% by 2030.

 

We continued improving our bauxite residue storage efficiency in 2014 after meeting our 2020 goal seven years ahead of schedule in 2013. We also saw positive movement in our rehabilitation rate, but challenges remain in meeting our residue reuse goal.

 

Bauxite Residue Storage Efficiency
Square meters of land required per thousand metric tons of alumina produced
Goal: 15% reductionProgress: As of Dec. 2014 
16%

 

Bauxite Residue Storage Area Rehabilitation Rate
Percent of total area rehabilitated
Goal: 30% rehabilitatedProgress: As of Dec. 2014 
16%

 

Bauxite Residue Reuse
Percent of total residue generated
Goal: 15% reusedProgress: As of Dec. 2014 
0%

 

Bauxite Residue Intensity
Metric tons per metric ton of alumina produced

 

One focus area of our ongoing bauxite residue research is improving residue storage practices to reduce potential environmental impacts. For example, we control wind-blown dust via water-spray systems. In the 1980s, we transitioned from wet storage ponds to an innovative dry stacking process in Western Australia that subsequently became an industry best practice. This process minimizes the amount of land required for storage, reduces the risk of groundwater contamination, increases the speed of rehabilitation, and reduces safety hazards to people and animals.

 

In late 2014, we selected an innovative technology known as residue filtration for our Kwinana refinery in Australia. With this technology, bauxite residue is forced through very large filters that squeeze the water from the mud, with the water being recycled in the refining processes. Because of the technology, the refinery will not need to construct another residue storage area for around 20 years compared to every five years previously. We anticipate using this technology at other refineries around the world.

 

Residue storage area at the Pinjarra refinery

A residue storage area at the Pinjarra refinery in Australia includes adjacent land that has already been rehabilitated.

We are also working to improve how we close residue storage areas once they are full. While imported fill can be used to cap the areas, we are investigating transforming the residue into a viable soil layer that can sustain a vegetative cover and initiate a more natural remediation.

 

We have globally mandated standards involving the construction, management, and maintenance of our residue storage areas. An independent third-party professional also conducts an annual geo-technical inspection of the areas to ensure they are maintained and operated to our specifically mandated standards. This is in addition to operating within local, regional, and federal standards. 

 

Our efforts to reuse bauxite residue have been slower than we would like despite advancements we have made in modifying the residue—particularly decreasing its alkalinity—to enhance its prospects for reuse. One major impediment is that no regulatory framework exists to assess bauxite residue for reuse in many of the countries where we operate refineries. We are working with various government bodies to create such a framework so innovations in our research pipeline can be approved much faster.

 

Despite that challenge, we have introduced a number of products made from bauxite residue. Alkaloam®, which is a fine-grained bauxite residue that is carbonated through a reaction with carbon dioxide, increases the pH of acidic soils almost instantly compared to years for agricultural lime. ReadyGritTM is a red-colored crushed rock material that can be used for general fill, construction backfill, turf top dressing, bunker sand, and road bases. Bauxite residue is also used in our innovative Natural Engineered Wastewater Treatment (NEWT™) system (see the Water section for details).

 

Landfilled Waste

Minimizing the waste we produce and finding uses for that which we do generate will help us achieve our strategic target of a 75% reduction in landfilled waste by 2020 and 100% by 2030 from a 2005 baseline.

 

This goal excludes certain waste streams, such as bauxite residue and fly ash, since these would mask our progress on reducing landfilled waste. We have separate programs to minimize and reuse these high-volume wastes. In addition, overburden and rock generated from our mining activities are not included since both materials are reused in mine rehabilitation and are not considered waste.

 

In 2014, we saw a very slight increase in landfilled waste primarily due to waste generated during construction activities at our rolling mill in Tennessee, USA. Since 2005, we’ve achieved a 23% reduction.

 

Landfilled Waste
Thousands of metric tons
Goal: 75% reductionProgress: As of Dec. 2014 
23%

 

Total Wastes Sold or Recycled
Thousands of metric tons
Increase in 2011 was due to improvements in the recycling of spent pot lining and an increase in plant demolitions that resulted in significant recycled waste.

 

Many of our locations continued their efforts to reduce landfilled waste in 2014. At our smelter in Avilés, Spain, for example, a waste-management kaizen (rapid improvement event) resulted in a 22% reduction in hazardous waste generated, a 14% decline in hazardous waste landfilled, and US$144,000 in cost savings during the year. Efforts included reusing wastes, training employees on waste management, and ensuring waste segregation points were accessible throughout the plant.

 

Our Global Rolled Products business set a goal to reduce landfilled waste at each of its locations by 37.7% in 2014 compared to a 2005 baseline. Each plant decided which wastes to focus on and then partnered with waste vendors to identify reuse or recycling options for each. Examples included recycling refractory bricks and reformulating oily wastes to facilitate recycling options. The business achieved a 50% reduction worldwide at the end of 2014.

 

Spent Pot Lining

Spent pot lining (SPL) is the carbon and refractory lining of smelting pots that have reached the end of their serviceable life.

 

Our approach to managing SPL is to first minimize the volume we generate by using technology and processes to reduce pot failures and increase the lifespan of a smelting pot. Both result in fewer pots that need their lining removed and replaced.

 

We have been a leader in finding ways to transform the SPL that we generate into a raw material or fuel source for other industries. For example, the cement industry uses SPL as fuel and a raw material. It is also a raw material used in the production of steel and a fuel source in the manufacture of rock wool insulation.

 

We recycled 52% of the SPL we produced in 2014, which is a 16% decline compared to 2013. Low cement production in the United States during 2014 reduced our opportunities for SPL recycling.

 

Spent Pot Lining Generated
Kilograms per metric ton of aluminum produced
Beginning in 2011, generation rates do not include demolition tonnage from permanently idled smelters. The increase in 2011 was due to the additional SPL generated as a result of restarting smelters, while a higher number of pots reaching the end of their serviceable life was the primary factor for the increase in 2014.

 

Spent Pot Lining Recycled/Reused
Percent
Decreased recycling in 2012 and 2014 was due to lingering weakness in the cement industry and/or significant one-time remediation tonnage resulting from the permanent closure of several smelters for which recycling capacity was not available.
 
Air Emissions

Our locations produce different types of air emissions depending upon the manufacturing process. Mercury, for example, is primarily emitted by our refining operations, while our smelters account for the bulk of our greenhouse gas and fluoride emissions. (See the Climate Protection section for a discussion on greenhouse gases.) We continue to work at a global level to reduce these and all emissions to industry benchmark levels.

 

Mercury is a naturally occurring element found in the bauxite that we refine into alumina. Because the concentration of mercury varies considerably based on the source of the bauxite, we are challenged to develop solutions to reduce these emissions. As such, progress against our strategic target of an 80% reduction in mercury emission intensity by 2020 and 90% by 2030 from a 2005 baseline is behind schedule. In 2014, we maintained intensity at 0.20 grams per metric ton of alumina produced, but our absolute mercury emissions increased due to higher alumina production.

 

Other emissions that we track globally, but which often are significant to specific operations or regions, include sulfur dioxide, nitrogen oxide, and volatile organic compounds. All three posted declines in 2014, primarily due to reduced aluminum production.

 

Mercury Emission Intensity
Grams per metric ton of alumina produced
Goal: 80% reductionProgress: As of Dec. 2014 
9%

 

Mercury Emissions
Thousands of kilograms
The 2013 data change from prior reporting is due to the addition of mercury emissions from power production.

 

Sulfur Dioxide Emissions
Thousands of metric tons

 

Nitrogen Oxide Emissions
Thousands of metric tons

 

Volatile Organic Compounds Emissions
Thousands of metric tons

 

Fluoride Emissions
Kilograms per metric ton of aluminum produced
 
Ozone-depleting Substances

We use halon gas as a fire suppressant in several locations throughout the world, and we continued efforts to phase out these systems in 2014. We have had no documented releases from a halon system since 2004.

 

Fugitive Emissions

Fugitive emissions, such as dust, are generally defined as those that are not emitted or released from a chimney, stack, or vent. Controls we use to manage or minimize fugitive emissions from our mining and process operations include the watering of haul roads, storage piles, and bauxite residue areas to suppress windblown dust. We also use capture and control systems for loading/unloading, material handling, aluminum reduction, and other process operations. We frequently employ visual-emission observation and ambient-air monitoring as tools to verify the effectiveness of these controls. 

 

Compliance

Our robust environmental compliance tracking system ensures we rapidly correct any actual or potential incident, such as a spill, that is not compliant with applicable environmental laws and regulations. We also use an environmental permit review process to ensure that permit applications, draft permits, and final permits are effectively reviewed, commented on, and submitted in accordance with regulatory requirements.

 

In 2014, 69% of our operating locations operated without any environmental non-compliance incidents compared to 59% in 2013.

Environmental Incident Rate
  Spills Over 20 Liters Major Spills Environmental Incident Rate per Location
2010 599   2 9.2
2011 560   4 7.3
2012 562   9 10.1
2013 497   4 9.1
2014 578   1 8.0

 

2014 Major Spills
Material Spilled
Volume
Liters
Environmental Impact
Process wastewater 2,270 No impact. No measurable residual contamination remains.

This spill was characterized as a major environmental incident according to our Environmental Incident Management System. It was not reported in our financial statements as a significant spill, as it did not result in significant environmental harm or financial impact.

 
Environmental Capital Expenditures

Our capital expenditures for environmental purposes vary each year based on the number and type of projects implemented. In 2014, we invested US$129 million in capital projects primarily focused on improving environmental control systems.

 

For any capital expenditure request exceeding US$2 million, including those not focused on environmental projects, members of our corporate environmental staff conduct a review to ensure that the work to be carried out incorporates best practices and the completed project minimizes additional impact on our environmental footprint.

 

Environmental Capital Expenditures
Millions of U.S. dollars