How to recycle zinc ?
The process used allows Recytech to recycle zinc-rich industrial waste. This consists in separating zinc from the other elements contained in this residue by pyrometallurgical reaction. The material containing the zinc recovered is called Waelz Oxide, after the name of the process used.
A constantly improving process
A pelletizing unit is used for storage and for mixing the precise quantities of components necessary for the reaction. The zinc oxide contained in the mix is reduced in the presence of carbon at a temperature of 1 200°C (2 192°F) inside a rotating furnace called a Waelz kiln. The kiln operates continuously, 24 hours a day. The zinc thus volatilised is re-oxidized in a gas phase by supplying oxygen. At the upper end of the kiln, the zinc-bearing gas is sent to a dust chamber where it is cooled by water spraying and then air-quenched. Once out of the cooler, the Waelz oxide goes through a bag filter to be recovered. At the other end of the kiln, the slag is extracted on an on-going basis.
Since 2004, Recytech has improved the performance and the environment impact of the process through the implementation of an innovating process, with the support of Conseil Régional du Nord/Pas-de-Calais, ADEME and the European Union.