Recovering residues to save on raw materials
While thermally treating waste, we aim to recover as many materials as possible. We do this by means of a sophisticated ash treatment. Residues from our treatment processes replace valuable raw materials in our processes.
Ash treatment following thermal treatment
Of the total quantity of waste that we treat in the grate incinerators, less than 3% is deposited in landfills as residue fraction of ash treatment. The bottom ashes from our own installations, and possibly from other household treatment plants, are washed and sieved and all impurities removed. The ash-treatment installation in Doel processes the ashes into a useful end-product for the metal or construction industry:
- ferrous and non-ferrous metals are separated by various crushing, sieving and washing units and are sold to the metal industry as a secondary raw material;
- granulates are used for the construction of dykes and in construction, for example in foundation works, for their draining capacity, among other reasons;
- sand fractions are put to good use in construction and stability applications in landfills.
Residues replace valuable raw materials
We want to replace as many valuable and primary raw materials as possible with waste in our processes. The physicochemical units at the Antwerp plant treat industrial liquid and solid inorganic waste. This way, we replace auxiliary materials, such as lime and cement, as much as possible with residues from our processes, thus saving raw materials.
- In the installation IndaChem Liquids, where we process liquid waste from metal treatment, we replace at least 50% of the quicklime (almost 1,000 tonnes), which neutralises the contamination, with residues from our incineration process. In addition, we use acid wastes instead of iron (III) chloride (FeCl3), which saves another approx. 600m³ of raw materials.
- In the installation IndaChem Solids, where fixed inorganic waste is mixed with cement, lime and chemical substances to catch polluted substances so that the waste can be disposed of, the cement is partially replaced by certain residues.