This study focuses on the stabilisation/solidification (S/S)treatment of air pollution control(APC) residues
from municipal solid waste (MSW) incineration. Six formulations (T1–T6) were tested based on different
cements as binders, for the immobilisation of pollutants and to prevent their entering into the environment
at unacceptable rates. Soluble phosphates and silicates were considered in some cases to fix heavy
metals. The performance of T1–T6 products was measured in terms of initial and final setting times,
mechanical strength, total availability and leaching from S/S products. Two monolithic leaching tests
were used to estimate emissions of pollutants over 48 h and 64 days.
The results showed that the setting time was reduced when soluble phosphates were used. Moreover,
although all the treatments have met the threshold of 1 MPa for unconfined compressive strength, this
parameter was significantly reduced due to matrix dissolution during immersion. After three cycles of
leaching,the limit of 10% for solubilisation was exceeded for alltreatments with the exception of T5 (with
phosphates).
This study demonstrated that the S/S treatment used at the industrial level can be improved with
respect to toxic heavy metals, by using soluble silicates or phosphates, but not regarding soluble salts