Stora Enso mill in Barcelona, Spain, develops method to recover aluminum from recycled paperboard, produces 1,200 tonnes/year of aluminum; 90% of milk, juice cartons sold in Spain lined with aluminum
November 25, 2011
– A Stora Enso mill in Spain has developed a whole new method to recover aluminium. 90 percent of juice and milk cartons are lined with aluminium.
Colourful paperboard bales fill the yard at Stora Enso’s Barcelona mill, with bright yellow stairs/ladders among them. As the sky is also deep blue, the effect is considerably more colourful than at any Finnish paper or pulp mill.
After all, this region, Catalonia in Spain, is the home ground of architect Antoni Gaudí.
Used juice and milk cartons fill the yard because the mill uses aluminium-lined recycled paperboard to make packaging paperboard.
The people at the Barcelona Mill have developed a unique method to recover both the aluminium and the energy contained in the plastic coating. The method is needed, as about 90 percent of the milk and juice cartons sold in Spain are lined with aluminium.
The mill produces 1,200 tonnes of aluminium
In the method developed, the paperboard pulp is heated to 400 degrees Centigrade. This is done in vacuum, so the pulp will not catch fire but the plastic is gasified.
“The cooled-down gases are incinerated for energy,” explains Mr. Juan Vila, Director of the Barcelona Mill. The process produces more energy than the mill needs, so the surplus is sold.
The recycled fibres are used to make paperboard and the aluminium ingots are sold. The mill produces 1,200 tonnes of aluminium per year.
The method, unique even in global terms, was developed jointly by Stora Enso and Alucha Recycling Technologies. The method has received awards.
Finland uses less aluminium in cartons
The situation in Finland is different. Here, only about one third of the milk and juice cartons are lined with aluminium.
However, Finns use a lot of milk and milk-based products. “They are packed in what we call gable top packages and transported and stored in chilled conditions. Therefore we don’t need or use aluminium in these packages,” says Mr. Juha-Pekka Salmi, Director of the company Suomen NP-kierrätys Oy. Suomen NP-kierrätys Oy is part owner of the company responsible for the recycling of liquid packages.
Aluminium is used in aseptic liquid packages made of paperboard. These packages can be stored in room temperature.
Products in aseptic packages must be manufactured so that they will keep in room temperature. In Finland, the most common example is lactose-free ultra-pasteurised milk.
Households use 100,000 tonnes of paperboard
Until the end of 2006, milk and juice cartons had separate recycling bins in Finland. Nowadays households can put all paper- and cardboard into to same recycling bin.
Salmi says the goal was to make recycling as easy as possible for consumers. The strategy worked.
In 2006, households recycled 22,000 tonnes of paperboard every year. This year, the figure is expected to reach 40,000 tonnes.
Finnish households use 100,000 tonnes of various grades of paperboard every year. Around 31,000 tonnes of this consist of liquid packages. Around one third of the liquid packages are recycled.
Salmi is relatively happy with the recycling rate of liquid packages, especially when one takes into account the sparse population and long distances in Finland.
Aluminium in cartons is not recovered in Finland
Stora Enso’s Barcelona Mill alone uses 30,000 tonnes of recycled liquid packages every year, which equals the annual consumption in Finland. The majority of the packages used by the mill are obtained from the Catalonia region.
The liquid package paperboard recycled in Finland is converted into new cardboard by either Corenso in Pori, Finland, or Fiskeby Kartong in Sweden. In both mills, the paperboard is first pulped, after which the fibres are separated.
The residue, called reject, such as plastic and aluminium, is incinerated for energy. The incineration requires a permit, which states that the combustion gases must be cleaned.
There is so little aluminium in the reject that so far it has not been worthwhile to separate it.
Spoiled goods cause environmental hazards
Salmi points out that in the debate on the environmental impacts of packaging, important functions of packages are often forgotten: they protect the product during transport and improve its shelf life.
According to a study published by the MTT Agrifood Research Finland earlier this year, a package can even lessen the environmental impacts of some foodstuffs if the package protects the food from getting spoiled.
The environmental impact of the package is small compared to that of the contents. The MTT study found that throwing away half a slice of rye bread or a slice of ham caused more of an environmental impact than the manufacturing of the package and waste management combined.
Buying a larger-size package is not better than a small one, if part of the food ends up not being consumed and is thrown away. In Western countries, as much as 120 kilos of food per person is spoiled every year, while in Africa the figure is less than 10 kilos per person.