J. Giro-Paloma, J. Mañosa, A. Maldonado-Alameda, M.J. Quina, J.M. Chimenos
https://doi.org/10.1016/j.jclepro.2019.06.010
Journal of Cleaner Production, 2019, Vol 232, Pages 713-721
Quartile Q1, Impact 7.246
This study assessed the technical feasibility of formulating lightweight aggregates (LWA) from municipal solid waste incinerator bottom ash (IBA) and residual biomass. Weathered IBA (WIBA) particles larger than 8 mm contain a mixture of calcium-rich compounds and other silicates mainly composed of glass and synthetic and natural ceramics, with low contents of heavy metals and soluble salts. Unfired LWA were formulated with the particle size fraction of WIBA larger than 8 mm and rice husk (RH) used as the bloating agent. Rapid sintering of the unfired spherical pellets at 1,100 ºC for 5 min produced some cohesive sintered LWA, whose porosity, apparent particle density, water absorption, and compressive strength directly correlated with the percentage of RH added. The fired LWA formulated with 5 wt% of RH showed the highest bloating index (115%) and porosity (53%) and the lowest apparent particle density (0.61Mg m-3) and compressive strength (1.4 MPa). The addition of more than 5 wt% of RH increased the internal temperature of the sintered aggregates and decreased the viscosity of the molten glassy materials, resulting in the collapse of the inner structure. Consequently, the porosity decreased and the apparent density of the particles increased, thereby shrinking the volume of the fired LWA. According to the standard leaching test (EN 12457-4), both the unfired precursor and the sintered aggregates showed concentrations of heavy metals and metalloids in the leachates that were well below the safety limits established for their reuse as secondary materials.
Funding
The work was partially funded by the Spanish Government (BIA2017-83912-C2-1-R) and by an STSM Grant from COST Action CA15115.
Research line: Environment, Construction
Projects associated: BIA 2017