The majority of household residual waste is burned for energy recovery, and this results in a significant quantity of incineration ash. Valuable metals, such as copper or aluminium, are extracted in a first stage, producing a purified mineral fraction, which is what we are trying to find high-quality applications for. AshCem, a project funded by the SIM-Flanders (strategic materials initiative) spearhead cluster as part of the MaRes programme intends to find out how the purified mineral fraction can be used in the production of construction materials such as cement or CO2-bound concrete products such as clinker bricks. VITO is working on this project together with UGent, Indaver, Orbix and CRH.

Indaver is already recovering a large proportion of the metals in incineration residues; coarse metal fractions rich in steel, iron or aluminium and copper are being recovered. At present, the remaining mineral fraction is partially used in construction applications. If we were able to fulfil both technical and environmental hygiene requirements using certain procedures, we could tap into more valuable applications. One of the challenges is to remove fine metal particles, as finely distributed aluminium particles can cause undesirable chemical reactions that could have a negative impact on the technical properties of construction products. VITO is investigating how these tiny aluminium residues can be effectively neutralised using an innovative pre-treatment process. VITO is also looking at how this material can be used in construction materials that are bound using CO2 instead of cement.

The AshCem project was launched in September 2015 and is due to end in September 2019.