Hydrothermal solidification of municipal solid waste incineration fly ash

Abstract

Hydrothermal solidification of municipal solid waste incineration (MSWI) fly ash has been conducted under saturated steam pressure at 200°C for up to 48 h with quartz addition. To enhance the strength of solidified specimens further, the raw fly ash was pre-treated by water-washing and mixed with NaOH solution (2 M) as reaction solvent. Experimental results showed that curing time and temperature had significant effects on strength development. Strength development was found to be mainly due to tobermorite formation, and addition of quartz and NaOH solution promoted tobermorite formation. The raw fly ash could also be used as an additive to solidify MSWI bottom ash, and with raw fly ash addition (10%) the flexural strength of solidified specimens reached more than 21 MPa, suggesting high potential to recycle 100% MSWI ash (e.g. as 10% fly ash ? 90% bottom ash). Leaching tests were conducted to determine amounts of heavy metals dissolved from solidified specimens. The results showed that under the hydrothermal conditions of this study, leaching of heavy metals was very low. As such, the hydrothermal processing method might have high potential for recycling/reusing MSWI fly ash on a large scale.

Integrated carbon dioxide/sludge gasification using waste heat from hot slags: Syngas production and sulfur dioxide fixation

“…S2(a)-(b). The results show some remarkable variation trend including the position and relative intensity of different bands, peaks and shoulders, indicating the variation of the functional groups during gasification (Barroso-Bogeat et al, 2014;Chen et al, 2002;Prokopowicz et al, 2014;Shan et al, 2011). The detail assignments are displayed in Supplemental Table S1.…”

Aggregate material formulated with MSWI bottom ash and APC fly ash for use as secondary building material

“…In spite of this, the concentration of soluble salts is barely depleted and the final mass of the residue to be landfilled is severely increased (Quina et al, 2010). Hydrothermal solidification of FA was carried out by Shan et al (2011), who obtained solidified bodies with significant strength and a high potential to be recycled as this treatment dramatically reduces the concentration of the heavy metals dissolved. Composites made from a ternary blend of APC residues, concrete and polymer also appear to show improved retention properties (Massardier et al, 1997).…”

High-Strength Solidification of Fly Ash/Carbide Slag and Its Fixing Ability for Heavy Metals

“…It can be seen that a layer of interlinked, needle-like tobermorite was formed uniformly on the surface of the particles. Because of this structure, the compactness of the particles was enhanced, leading to higher compressive strength [19]. and the tobermorite with the interlocked structure may be playing a crucial role in fixing heavy metals [20].…”