The characteristics study on sintering of municipal solid waste incinerator ashes

The study examines the sintering of incinerator ashes from municipal solid waste while considering the compact pressure, sintering temperature, and sintering time. Experimental results indicate that the compressive strength primarily influences the compact pressure used in forming the specimens. The specimens' strengths increase at a sintering temperature ranging from 1120°C to 1140°C. However, the strength decreases with an increasing ignition loss of incinerator residues. As heavy metals are fixed and/or sealed in the sintered incinerator ashes, the process generates a ceramic-like solid having a sufficiently low metal leachability. The Pb, Cd, and Cr concentrations of the leachate from the Toxicity Characteristic Leaching Procedure (TCLP) test are 0.10-0.70 mg/l, 0.05-0.30 mg/l, and 0.35-1.25 mg/l, respectively, all complying with the regulatory limits of Taiwan EPA. The above results point toward the feasibility of recycling the incinerator ashes as a construction material by sintering.