Air: reducing the diffuse emissions in Belval and Differdange

• Dust emissions
• NOx emissions
• SOx emissions

In the past, powdered materials such as lime or anthracite used along with scrap in steel manufacturing were put in the furnace in open trolleys and this could generate diffuse emissions in dry weather. A system was introduced at the Differdange site in 2016 involving injecting the powdered raw materials into the electric arc furnace via conveyor belts. The materials are firstly delivered in completely sealed silo trucks. These are then unloaded in special silos that have no contact with the outside environment. Lastly, a system of enclosed conveyor belts supplies the furnace so that no material is lost and dust emissions are minimised.

• 2.3 euros per tonne of crude steel saved
• 1.7 kg of dust pollution per tonne crude steel prevented

An extraction hood was also installed at the site to capture diffuse emissions from oxycutting of semi-finished products from the rolling mills. Mobile extraction captures dust which is then collected by vibrating filters.

• 50 to 70 tonnes of dust recovered per month then converted within different routes

At Belval, a sprinkler area for electric arc furnace slag has been created to limit dust escaping when slag is being loaded onto lorries before being transported for recovery. Prior to loading, the lorry is positioned on the sprinkler area ramps. The loader driver positions his slag-filled bucket close to the lorry. The spray system, which uses industrial water, is then activated. The driver can then unload the slag into the lorry under a fine mist of water emitted from the sprinkler ramp.