Recycling rolled zinc: the best rate in the sector!

 

 

 

 

 

Roger Baltus will now have a regular guest contributor to his column: Cécile Roland, Environmental Applications Manager with VMZINC. An opportunity for architects, project owners and all building professionals to (re)discover the “sustainable” qualities of zinc.

Today, numerous buildings aim for high environmental performance, i.e. energy and carbon efficiency, increased recycling of site waste, preservation of natural resources, etc. In this context, it is interesting to recall the extent to which rolled zinc contributes to reaching this ambitious objective, thanks in particular to the effectiveness of its recycling at end of life.

Major arguments that are convincing!

All metals have high recycling rates. But rolled zinc has an exceptionally high rate. Although, in principle, rolled zinc is 100 % recyclable, in reality, it has an effective recycling rate of 96 %1in Europe and 98 %2 in France.

In concrete terms, over 100,000 tons of rolled zinc are recovered and recycled annually in Europe, i.e. the equivalent of a surface area of 20 km2 or a quarter of the roofs in Paris! Thanks to this record high recycling rate, every year, 1 to 2 million tons of zinc ore are not extracted worldwide and therefore left in nature. (3)

These arguments prove decisive when convincing public and private design teams to install rolled zinc on facade and roofing. Specifying zinc for a project means creating a sort of urban stock of zinc that can be easily mobilised by future generations when buildings are rehabilitated or destroyed. It also means choosing a material that uses natural resources sparingly and efficiently.

A highly structured and profitable recycling sector

Used rolled zinc that is recovered during rehabilitation or demolition work retains all its initial intrinsic properties. It therefore remains a highly pure zinc that has an attractive market value for roofers who collect it and sell it to recyclers, who in turn resell it to transformers for a price that is always lower than that of primary zinc.

For this reason, and for several decades now, recycled zinc recovered from used rolled zinc has become a material that is popular in industries using zinc such as galvanisation of steel, and production of brass or zinc oxide. The used rolled zinc recovery and recycling sector is therefore organised in a highly structured manner, contributing to a rate of recycling that is one of the highest in the building sector.

What happens to the recycled zinc?

The recycled zinc that comes from used rolled zinc is not re-used to produce new rolled zinc. Often more than one hundred years old, used rolled zinc that is recovered today has a chemical composition that does not correspond to current standards and requirements applying to the manufacture of new rolled zinc.

As mentioned above, recycled zinc from roofing applications and rainwater systems is however used in the galvanisation of steel, to manufacture the brass-zinc oxide alloy used in metal structures, security barriers, tap fittings, engine parts (*), tyres (**) and even in the composition of sun creams (***)! So our entire daily lives benefit indirectly from the recycling of used rolled zinc!

Watch this space next month. On the agenda for the next column: zinc, a sector working for the circular economy!

In the mean time, we welcome your comments and questions!

Cécile Roland
Environmental Applications Manager

 

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(1) Recycling of rolled zinc – Institut i+c Report – 2011

(2) Recycling Fact sheet – IZA (International Zinc Association)

(3) Source: Rezinal 2014

(*) zamak: Zamak is an alloy of zinc, aluminum and magnesium and copper

(**) zinc is a vulcanisation agent in the manufacture of tyres:

(¨***) zinc protects against UV rays