Packaging Matters

Are Beverage Cartons Recyclable? Part II

Are Beverage Cartons Recyclable? Part II

Briks: Sustainable? Recyclable?

In Part I we saw that briks or cartons can be considered fairly sustainable, but…

Are briks recyclable?

So far they briks seem quite sustainable in the production and use stages, but what about waste management? According to the waste hierarchy pyramid, recycling is one  the most favored waste management option after reuse (not possible in the case of cartons).

Source: http://www.wrap.org.uk/sites/files/wrap/Final%20Report%20Retail%202010.pdf

In the official version paper is separated from aluminum and polyethylene in hydrapulpers. Paper is later  recycled into paper, solid board or corrugated carton. The  aluminum and polyethylene mix – polyAl  – for short can be used to manufacture tiles, panel boards, and used in general as a construction material.

Source: https://www.tetrapak.com/in/sustainability/good-for-you-good-for-the-earth/how-do-cartons-get-recycled

Of course recycling can only be possible after a sorting and pressing stage, and kerbside recycling is not available everywhere.

However, the main recyclability issue of briks is that polyAl does not close the circle.

Today, only about half of the globally available plastic-aluminium mix is recycled, and it presents a series of problems:

  • Very few uses
  • Variable quality
  • Logistic  costs

What to do with polyAl?

The polymer-aluminium mix has been used in many countries to produce a diverse range of goods from pellets for injection moulding to pressed boards.

However, the polyAL mix can currently only be used for few products after extrusion. moroover, there is variation in the properties depending on where the material comes from, i.e. which types of packages and how they have been processed.

The plastic-aluminium mix is usually moist, and may have traces of paper fibre, and other materials such as metal, sand, glass,and wood coming from the household collection streams.

Logistics costs are high compared to material value. Material is bulky and heavy and it often contains water.

Separations

Separating the plastic from the aluminum is complex and requires specific machinery and large volumes which are (not easily available) Hera are some examples of processes to separate aluminum and plastic (5, 6, 7, 8, 9) most of them using dissolvent (chloroform).

Pyrolysis

In 2010 Stora Enso  announced  a new brik-recycling  process in carried out in their Barcelona plant. Once separated form the paper and being dried, the polyAl is exposed the material to 400ºC of heat in an oxygen free chamber (a previous attempt in Finland that failed for economic reasons needed 800 ºC).Source:  http://www.consumer.es/web/es/medio_ambiente/urbano/2011/10/12/203750.php

The heat causes the plastic to evaporate while the aluminium stays where it is. The evaporated gas can be used to generate electricity while the aluminium remains un-oxidised and can be recycled and re-melted without problems to be used to make new aluminium products.

This means both fibre and aluminium can be fully reused and the plastic to utilised to generate energy in the mill.

The recovered fibre is used for the production of white lined chipboard at the site.

Conclusions

Composite cartons or briks are low weight containers mostly made of renewable materials, with great logistics efficiency that guarantees a long shelf life. LCA analyses show that they are generally more sustainable that the alternatives,

Their main component –paper- is recyclable, however the aluminium and plastic (low density polyethylene or LDPE ) are not.

The uses of the polyAl complex are very limited and the LDPE/aluminium separation usually needs  organic solvents.

The most promising solution seem to be pyrolyzing the mixture using the LDPE as an energy source to recycle the paper and the aluminium.

New alternatives like EVOH barrier pouches could be more sustainable for certain applications and products, but the final waste material consists on a mix of plastics  that is not separated and has not may uses.

Meanwhile, while far from optimum, cartons seem to be a more than adequate solution to guarantee a long shelf life with no refrigeration and usuing a minimum  quantity of material.

 

June 2018, Bruno Rey – The Packaging Blog –


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