Removing acid gas and micro-pollutants in a secondary smelter

The challenge

As a European leader in its field, this customer recycles annually 60,000 tonnes of end-of-life engines. The company uses the recycled metal to produce aluminium ingots, engine-grade cast iron, E40 milled steel, A4 cupola steel and custom alloys.

The gaseous effluents from the smelting process notably contain SO2 and HCl acid gases. These corrode facilities and produce micro-pollutants: dioxins, furans and heavy 
metals.

Reducing the acid gases and micro-pollutants requires the use of a multi-purpose sorbent. It must be:

  • alkaline to neutralize acid gases 
  • adsorbent to take up dioxins and furans

The Lhoist solution

To meet the customer’s reduction targets Lhoist designed a custom blend of Sorbacal® SP & Sorbacal® Micro 4099 with an optimized feed quantity. This type of blend offers the following advantages:

  • A unique, versatile and ready-to-use sorbent for the combined reduction of HCl, SO2 and micro-pollutants (dioxins, furans, PAHs and PCBs).
  • Only one storage and feed solution needed, reducing costs.
  • A 100% mineral solution that does not require ATEX equipment and presents no risk of combustion.

 

Sorbacal® SP:

Hydrated lime with a high specific surface area and high pore volume, Sorbacal® SP is designed to neutralize acid gases (SO2, HCl, HF) in a dry absorption process.

Discover Sorbacal® SP

 

Sorbacal® Micro 4099:

As an adsorbent, non-flammable and non-ATEX mineral reagent, Sorbacal® Micro 4099 reduces dioxins, furans, PCBs, PAHs and aromatic compounds.

Discover Sorbacal® Micro

The benefits

During installation of our first baghouse filter we opted for activated carbon injection to reduce micro-pollutants. But using this system proved very restrictive, and the product flammability risk forced us to abandon it during the renovation of our filtration equipment. Lhoist then worked alongside us and created a specific Sorbacal® Micro blend. This was injected into the suction duct using a single silo equipped with an injection screw. The results were tangible, and the simplicity of this treatment method definitively convinced us to choose a similar system on the new filtration line we installed when doubling our production capacity.

Feedback from the plant manager