Poland: coal ash is greening cement!
Posted on September, 11th 2018.
EKO-ZEC Veolia’s Polish subsidiary, recovers fly ash from coal combustion for use in cement production. Since the beginning of 2017, some of the surplus has been exported to other European countries.
In the end, it means improvement quality parameters of cement and therefore stronger and greener concrete structures.
In Poland, electricity is mainly produced in coal-fired power plants. But there’s a problem - the combustion generates a great deal of polluting waste. The best known is fly ash, which are fine powder, which is mainly composed of spherical glassy particles.
Added to this are gypsum – produced during the desulfurization (removal of sulfur) of the flue gas – and slag.
The legislation now means this waste has to be collected - including the fly ash. It is captured before sent to landfill, stored in silos and can be highly recyclable! And it’s exactly what EKO-ZEC - Veolia's Polish subsidiary - is responsible for on behalf of one of Poland's leading energy companies.
From coal to concrete
There’s nothing new about the process used to recycle coal combustion waste; it has been used for some fifty years across the world. And for good reason: coal ash is an excellent substitute for some of the materials that go into cement - clinker in particular. Produced when a mixture of limestone and aluminosilicates is fired, it is responsible for a large proportion of the world’s greenhouse gas emissions.
Using coal fly ash to make cement prevents it going to landfill as well as reducing greenhouse gas emissions during clinker production. Not to mention that as an industrial by-product, the price of ash is relatively low. And finally, the icing on the cake - ash improves cement hydraulicity (the ability to harden on contact with water). In the end, the cement is less expensive and better quality - which makes it possible to build stronger and more environmentally friendly concrete structures.
Responding to European demand
At its plant, the EKO-ZEC’s customer generates up to 650 000 metric tons of fly ash annually. This is far greater than the local demand, especially during the winter months when fewer construction sites are operating and there is less need for cement.
The question is what can be done with this surplus, in particular so it doesn’t end up in landfill. The solution is obvious: export it! In particular to countries with fewer coal plants.
The first combustion by-products shipment was exported between 13 and 18 February 2017. It was first transported by train from the Kozienice plant to the port of Gdynia, in the north of the country on the Baltic Sea. From there, one ship with a cargo of ash headed for Scandinavia and another laden with gypsum went to the Benelux countries. The ash will go into cement and the gypsum will be used to make plaster and mortar.
These new distribution channels mean EKO-ZEC and Veolia are contributing to Europe’s circular economy!
Credits : Veolia Library