Metal

Consideriations when using metal packaging

Advantages

• Metal has excellent barrier properties and chemical resistance, which means metal packaging materials can protect their contents well. Products in cans have a longer shelf life. As a result, less food is thrown out.
• The relatively low mass of metal packaging materials reduces their environmental impact. Metal packaging materials are relatively light, easily stackable and efficiently transportable.
• Metal packaging materials can easily be collected, sorted and recycled without loss of their inherent properties. Because of the mostly excellent recycling options, the metals used for packaging materials are generally widely available.

Drawbacks

• Mining metals and producing metal packaging materials are relatively energy-intensive processes. Metals are finite materials and - depending on their specific form - more or less scarce. 
• The mechanical protection requires extra attention because of the risk of mechanical damage such as dents.
   

Raw materials

Steel packaging materials are made from scrap metal, iron ore, coal and tin/polymers. Iron ore is imported from countries all over the world. With the help of coal, the iron ore is turned into crude iron by heating it. Crude iron and scrap metal can be used to make sheet metal. Per kilogram of packaging steel, approximately two grams of tin is used.

Bauxite ore is needed for the production of aluminium packaging materials. The aluminium compounds found in the bauxite are dissolved with lye. The resulting product is called alumina. Together with scrap metal, it forms the core ingredient of aluminium packaging materials.

The steel and aluminium are turned into rolls of ultra-thin sheet material, which forms the basis for new packaging materials. Manufacturers use this material to e.g. make cans that are as light as they are strong. Due to ongoing innovations, packaging materials are becoming lighter and therefore more efficient. Since the 1960s, the average weight of a 300 ml drink can has decreased by as much as 77%.
 

Applications

Because of its excellent barrier properties, metal is suitable for vulnerable products that need a long shelf life. Approximately 85% of all metal packaging materials are used for food products and beverages. To achieve chemical resistance, specific treatment processes and coatings can be applied.

Metals are also used for:

• canned goods, beverage cans, paint and oil cans made of tinned steel or – an increasingly popular option – plastic-coated steel;  
• aluminium trays;
• lids and crown caps 
• gas and liquids in aerosols;
• bulk goods in barrels and promotional packaging materials.

The production of the packaging materials and the packaging process are usually two separate processes. This means that the metal packaging materials must be transported to the packager while empty.

As with glass, this has a major environmental impact on the transport and storage of empty packaging materials, depending on the distance that the empty packaging materials must travel.
 

Recycling

Recycling allows the vast majority of the aluminium and steel that is produced to be reused over and over again. This results in the efficient and effective use of (new) raw materials. The biggest challenge with regard to closing the chain for metal packaging materials is making sure they end up in the correct waste stream and are not disposed of as litter.

Ferrous metals such as packaging steel and sheet metal are generally magnetic, which means they can be extracted from a waste stream with magnets. Aluminium packaging materials are not magnetic, but they can be charged with the help of an electric field (a so-called eddy current) and then separated from the rest of the waste stream with a special technique. However, this is not possible for composite materials that contain a thin layer of aluminium or vacuum-deposited aluminium, because the charge generated by the eddy current is too small to separate the aluminium from the waste steam.

After recycling, metal packaging materials can be reused to produce new packaging materials or for other purposes. Recycled metal can be used for all kinds of metal products, especially steel. For aluminium, the possible applications depend on the aluminium’s alloy.
 

Situation in various countries

Netherlands
In the Netherlands, 126 kiloton of metal packaging materials is used per year. It is estimated that more than 118 kiloton - 95% - are eventually recycled. The Dutch government's ambition is to make the Netherlands fully circular by the year 2050. This means that virtually all metals must be either reused or recycled by that time.