Aluminum is a valuable metal that when recycled has significant positive impacts on the economy and environment. As of 2016, scrap sellers received as much as $1,186 per ton for aluminum cans, according to The Aluminum Association’s The Aluminum Can Advantage, www.aluminum.org/canadvantage. This provides a much-needed built-in subsidy for curbside recycling programs.
When it comes to the environment, producing aluminum from recycled metal saves more than 90 percent of the energy needed for primary production. Additionally, the increased use of secondary aluminum in production reduces the amount of natural resources used to make primary aluminum.
The International Dross and Packaging Recycling Workshop, which was hosted by SINTEF, an independent research organization, and the Norwegian University of Science and Technology (NTNU) as part of Metal Production Centre in mid-May in Trondheim, Norway, addressed the benefits of and barriers to aluminum recycling as well as those associated with recovering the metal from recycling byproducts. Participants included Alcoa, Constellium, Gränges, Hydro, Infinitum, Kavli, Linde Gas, Metallco, Norsk Metallgjenvinning, Novelis, Real Alloy and Trimet Aluminum, as well as the European Aluminium Association, Brussels, and The Aluminum Association, Washington. The common theme was that recycling is good, but what is the best process?
As discussed in the workshop, aluminum can be returned to production in a number of ways. One way is postconsumer recycling, which includes aluminum cans, containers, and other forms of packaging. Many collection methods exist for postconsumer aluminum packaging, including single-stream recycling. This method is easy for consumers and can lead to more aluminum being recycled overall. The items are sorted by automated systems at material recovery facilities (MRFs). However, it can be difficult and take longer to sort those recyclables at MRFs because so many different materials are altogether. Aluminum also could be sorted incorrectly at MRFs.
Multistream collection systems collect materials like glass, metals and paper in separate receptacles, reducing the amount of sorting done at MRFs. Instead, sorting the recyclables falls to the consumer, which can complicate the process because of confusion and/or lack of awareness. Multistream collections can take place curbside, whereas some communities have town collection centers. Residents bring recyclables here to sort on location. Consumer education as to what can be recycled as well as what to separate is necessary. While multistream collection is present in the United States, it is prevalent across Europe.
Through deposit systems, 10 states in the U.S. incentivize consumers to return cans and other recyclables in exchange for cash. Consumer recycling rates in these states are higher than those without deposit systems. For example, California, a state with a bottle and can redemption system, has a recycling rate that is almost eight times that of Louisiana, a state without said system, according to CalRecycle. While deposit programs are not the sole contributor to such high recycling rates, they are clearly an indicator that the state works to recycle as much as possible. In fact, more than 40 percent of the cans recycled by the industry come from the 10 container deposit states, according to www.aluminum.org/advocacy/top-issues/beverage-can-management. Despite individual efforts to recycle, the U.S. has no nationally mandated consumer recycling policy. As of 2016, the consumer recycling rate for aluminum beverage cans in the U.S. dipped to just below 50 percent. While aluminum cans remain by far the most recycled beverage package in the United States, returning aluminum to the system must be increased on a national scale.
Overall, contamination is a problem, and proper education is key. While many know that items should be rinsed, how much residue is acceptable? If it becomes too difficult for a consumer to rinse out an item, or if they do not believe it has been cleaned well enough, consumers are likely to throw out the item. If facilities are able to collect items within a margin of error regarding cleanliness instead of only accepting items completely clear of residue, then more items will be able to go through the recycling process.
Confusion arises in part because municipalities differ on what is acceptable. More consistent guidelines communicated effectively to conscientious consumers would be helpful. Advocating the proper ways to recycle within each community is important in bringing aluminum back into the production cycle.
Another method to increase collection of aluminum is extended producer responsibility (EPR), which is widespread across Europe. Also known as product stewardship, EPR takes the sole responsibility for end-of-life product management off environmentally conscious consumers and instead shares that responsibility with initial producers as well as with each entity along the product chain. EPR reflects the true environmental impact of the product, therefore encouraging producers to improve the product design to minimize environmental impact to reduce costs, according to www.calrecycle.ca.gov/epr.
Aluminum also is returned to the system through postindustrial recycling, another topic of discussion at the workshop, which includes automobile recycling and metal scrap that arises during production. At more than 90 percent, the recycling rate for automotive aluminum is much higher than of aluminum used in consumer packaging, according to www.drivealuminum.org/wp-content/uploads/2016/06/Final-Report-Automotive-Aluminum-Recycling-at-End-of-Life-A-Grave-to-Gate-Analysis.pdf. This is partially because of aluminum’s high value and because of landfill tipping fees.
Processing molten aluminum creates the byproduct white dross, a substance made up of impurities and trapped aluminum that is skimmed off molten aluminum and that solidifies upon cooling. Much of the 15 to 80 percent metallic aluminum in white dross can be effectively recovered by adding the dross into a bath of molten salt in a rotary barrel furnace, with the residue remaining after metal removal (called saltcake or saltslag) having between 3 to 10 percent aluminum content. The metal recovered from dross is returned to the cast house, thus reducing the need for primary aluminum. The methods used to process dross vary, but in the end the goal is the same—to efficiently recover aluminum that can be used again in the processing system.
In the workshop, Real Alloy, Cleveland, outlined several ways to maximize the value of dross and the amount of aluminum that can be recovered from it. Reducing the amount of oxidation in the furnace and during transportation is key, as well as reducing the iron content and other contaminants prior to the remelting process. If the aluminum has too much contamination or iron pick up, it may be low quality and potentially unusable in higher quality production by the time it is concentrated in the dross. Minimizing oxidation plays an important role in reducing metal loss.
Oslo-based Hydro is attempting to reduce the amount of dross it produces overall, meaning the company is working to recover more aluminum earlier in the process. Its ultimate goal is to keep aluminum out of landfills.
Constellium, which is headquartered in Amsterdam, also is working to minimize the effect dross has on the environment while improving the overall process of recycling and the products that come from it.
As Pittsburgh-based Alcoa discussed, just as with any other process, returning aluminum to the system has its challenges. If the return on investment is not higher than the cost it takes to recycle, it is not economically viable. The recovery of dross, as well as postindustrial recycling more generally, continue to show the value of recycling aluminum. However, not all processes used to recover aluminum from dross have the same environmental impact. While the end goal of the process is no doubt important, challenges from cooling time to fumes and dust, as well as gasses that could be used in the process, create barriers to a completely efficient method. It is crucial that companies in the industry carefully weigh the environmental impact of their methodology to make sure they are getting the most out of their dross with as few setbacks as possible. Hurdles must be overcome in the process of reclaiming aluminum, but this metal is too important to end up in a landfill.
Closing the gap
The world is in agreement. Recycling, especially that of aluminum, is important. The workshop was able to highlight this through a multitude of meaningful and relevant presentations. Recycling aluminum allows for greater sustainability, lowers the cost of production and lowers energy usage. While efforts are in place to recycle aluminum, it is not enough in its present state. In the U.S. alone, nearly $800 million worth of aluminum cans are lost to landfills. The gap between postindustrial and postconsumer recycling efforts must be closed. The collection process does not need to be the same everywhere but should be more easily understood.
As discussed in the workshop, current recycling operations should not be replaced with completely new systems. Rather, they should be enhanced with the developing technology available, keeping the specific needs of the location in mind. During the workshop, it became clear that participants have a common goal but many solutions. While some of these solutions may compete with one another, it is crucial to keep the ultimate goal in mind” Aluminum must be kept from landfills and must be returned to its sustainable cycle of production. Looking at the needs of individual states and communities allows for a multitude of these solutions to be put in place while increasing the amount of recycled aluminum overall.
In a perfect world, a one-size-fits-all method easily could be implemented everywhere. However, given the complexities of different systems around the world, acknowledging the need to improve recycling rates while working out a solution to meet that goal within each specific community is more important than trying to come to one conclusion. While everyone does not need to use the same solution to prevent wasting aluminum, everyone must keep the same mission in mind. Recycling aluminum is worth it.