While recycling remains at the heart of the metal can’s sustainability story, the material’s inherent properties also offer economic and social benefits.
Steel and aluminium cans hold everything from soup to shaving cream, paint to bandages, cola to fruit cocktail. Offering an effective packaging option for centuries, the metal can has evolved in recent years to become more innovative, lighter in weight and significantly easier to recycle. Consumers have a high regard for metal packaging, crediting it as possibly the safest way to transport and store food and other products.
Consumer safety and long shelf life, in fact, are arguably the metal can’s most notable and time-tested attributes. Since the material is rigid and robust, the can is unlikely to be torn, broken or crushed during shipping. Cans are hermetically sealed, so microbes, oxygen, light and other agents cannot infiltrate, contaminate or degrade the contents. In addition to protecting foods and beverages, however, metal packaging guards the consumer against potentially hazardous substances, such as solvents and cleaning chemicals.
The metal can was invented to provide a way to bring safe, ample food supplies to Napoleon’s army on the battlefields. While the scenarios may have changed, the role that metal plays in protecting the supply of countless different goods remains unquestioned. This trust is a valuable asset for brand owners and product manufacturers to leverage.
The ability to infinitely recycle both steel and aluminium, with absolutely no loss or alteration in quality, is the highlight of the sustainability of metal packaging. Recycled in a true material-to-material loop (i.e., steel to steel), metals retain their original properties regardless of how many times they are recycled. Many other materials cannot make such a claim. As such, neither steel nor aluminium needs to be downgraded to less demanding uses after recycling. Both metals are permanently reusable. A beverage can could become part of a bicycle; an aerosol can or metal cap could become part of a new car; or a soup can could become part of a kitchen appliance, or another can.
While other materials promote recycling, there is a limit to the number of times such materials can be transformed into new packaging, especially for applications involving direct food contact.
Metals — including packages — have a long-term, well established recycling infrastructure, due to the economic value of the materials. Through street collection programmes, used metal cans are easy to acquire and even easier to separate from the household waste stream through a process of eddy
currents or magnetic extraction.
As steel and aluminium cans are made with a mixture of both virgin and
recycled content, it is not possible to trace the recycled content of any specific can. Its recycled portion could have been reused hundreds of times before becoming that actual can. This explains the inherent sustainability of steel to steel and aluminium to aluminium recycling.
Currently, steel cans have a 62 percent recycle rate in the US and 66 percent in the EU; aluminium can recycle rates are at about 50 percent in both the US and EU, according to data from the Can Manufacturers Institute. By comparison, plastic packaging is only at six percent reclamation in the US and 25 percent in the EU. The US Environmental Protection Agency’s ReCon model reports that steel cans have the highest recycle rate of any materials, followed by paper and paperboard, then aluminium cans.
Although primary metal production is relatively energy-intensive, recycling of scrap metals requires only a fraction of that energy. Steel recycling saves 70 percent of the energy required for primary production. Each ton of recycled steel saves 1.5 tons of iron ore and 0.5 tons of coal. Aluminium recycling saves 95 percent of the energy that is needed for primary production. Each ton of recycled aluminium saves more than four tons of bauxite, the primary ore from which aluminium is extracted.
This significant energy savings also translates to reduced greenhouse gas (GHG) emissions. Each ton of recycled steel saves 1.875 tons of CO2 (according to the International Iron and Steel Institute, IISI) and each ton of recycled aluminium saves 10 tons of GHG emissions measured in CO2 equivalents (according to the European Aluminium Association, EAA).
Abundant source materials
Aluminium is the most plentiful ore in the earth’s crust, usually as part of bauxite ore. Iron (the primary component of steel) is the second most common ore. Aluminium and iron are the third and fourth most common elements on earth, after oxygen and silicon. Neither element is in any danger of being depleted. Use of earth’s abundant resources is far more sustainable than depleting limited materials.
Recycled steel reduces the need for virgin materials, which lessens both energy demand and CO2 emissions. Global steel production is 1.2 billion tons, but only 1.5 percent of that total is used for packaging. At the present time, about 18 billion tons of steel are in use — somewhere, somehow — and therefore will be available in the future for recycling.
Less than ten percent of the global production of aluminium is used for packaging. Since the start of commercial aluminium operations 150 years ago, 75 percent of primary production is still in use. That primary production is still available for future collection and additional recycling.
A can-do attitude
In general, cans offer distinct benefits, especially for food, beverage and aerosol products, in addition to the protection and long shelf life they provide. First, cans help to prevent product waste. According to the Industry Council for Packaging and the Environment (INCPEN), of the total energy expended in the food chain, 50 percent is used in food production, 10 percent on the packaging function, 10 percent on distribution to retail, and 30 percent is used by the consumer in driving to and from the store and cooking/preparing the food.
The International Food Information Council estimates that, in developing countries, as much as 40 percent of available food products spoil before they reach hungry mouths. European surveys show that 30 percent of purchased food is thrown away without being consumed. Since cans protect contents so well against light, oxygen and microbe infiltration, they have the longest shelf life of any food packaging. Because of this, less product goes to waste.
Cans are also an economical form of packaging. First, cans fill the fastest on packaging lines. In addition, because of their inherent strength, cans require only minimal secondary or transport packaging during shipment. Cans need no refrigeration, or any ambient temperature control, during shipment and storage, reducing energy costs and CO2 emissions.
Cans are economical for the consumer, too. Canned foods require minimal cooking times, if at all, which further reduces energy use. Metal cans provide material and design simplicity, making them quite efficient to manufacture. In most can-making operations, the metal starts as a flat sheet and then is manipulated into the familiar one-piece canister. Shaped cans, which offer new design options, are becoming a popular alternative for brand distinction.
Lightweighting of both aluminium and steel cans is an on-going process. Engineering technology today allows can makers to reduce the thickness of can walls but still provide a high-performance container. Compared with 20 years ago, aluminium beverage cans are 28 percent lighter; steel food cans are 33 percent lighter; and tinplate aerosols are up to 18% lighter.
The can end, which is applied after filling, has likewise been substantially lightweighted. The SuperEnd beverage end from Crown Holdings, Inc. (Crown), introduced in 2001 specifically for the beverage market, has become an industry standard, with more than 150 billion ends produced. To date, Crown and its licensees who sell SuperEnd beverage ends have saved more than 37,000 metric tons of aluminium, over 600 metric tons of coatings, and more than 300,000 metric tons of greenhouse gases, which is the equivalent of the annual emissions
from 55,000 automobiles.
Metal packaging has earned its well-deserved reputation through a compilation of six achievements: protecting the health and safety of consumers, preventing food and product waste, using abundantly available natural resources, reducing material usage, providing economic advantages over other materials—and, most important of all, being infinitely recyclable with no degradation in quality.
As such, metal packaging earns its star on all three dimensions of sustainability: environmental protection, social equity and economic viability.
The author
Daniel Abramowicz
President
CROWN Packaging Technology, Inc
Philadelphia, PA, USA
E-mail: mdunleavy@crowncork.com
