Morphological and Chemical Properties of MSWI Bottom Ash with Respect to the Glassy Constituents

Abstract

MSWI bottom ash consists predominantly of x-ray amorphous, glassy constituents. A thorough characterization of the glassy constituents could provide insight into both long term leaching and suitability for technological applications of MSWI bottom ash. In this study the bottom ash glasses were examined using conventional and advanced microanalytical techniques. The glass content of the bottom ash sample used in this study was estimated at 75% (w/w). Although the identity of all crystalline phases was very difficult to establish, seven minerals were identified. Automated particle analysis revealed that the major element composition (Si, Al, Ca and Fe) varies little with particle size for particles smaller than 1000 pm diameter, which may indicate complete transformation in this particle range. Inter particle heterogeneity is observed in ash particle composition, with varying quantities of network formers and modifiers. Reducing the scale of observation reveals the existence of different phases within individual particles. Over 50% of the surface area of the ash particles belong to silicon rich, calcium-silicon rich, and aluminum-silicon rich particles types. From a morphological and chemical point of view volcanic ashes and MSWI bottom ash exhibit a close similarity. Knowledge of weathering processes based on studies of volcanic ashes can be used to predict long term leaching behaviour of MSWI bottom ash.

Detailed characterization of particle size fractions of municipal solid waste incineration bottom ash

“…The major elements found in MSWI BA fractions were Si, Ca, Fe, Na, S, and Mg, which is in accordance with mineralogical data Table 1 Main mineral phases in the composition of 6 combined particle size fractions of MSWI BA. (Section 3.2) and literature (Zevenbergen et al, 1994). Fig.…”

An appraisal of the potential use of fly ash for reclaiming coal mine spoil

“…Mercury, for example, tends to be undetectable in Indian FAs, but present in measurable concentrations in FAs from Europe, North America and Australia. Generally, the glass phase and the magnetic fractions in combustion residues contain most of the potentially toxic elements (Zevenbergen et al, 1994;Kukier et al, 2003). Trace metals and salts in fly ash may adversely affect plant colonisation and growth, soil microbial activity, and nutrient balance in plants (Wong and Wong, 1986;Pichtel and Hayes, 1990).…”

Zinc distribution in soils amended with different kinds of sewage sludge

“…This increase in the residual fraction may indicate that the element was occluded in secondary minerals during incineration. Likewise, Zevenbergen et al (1994) indicated that most PTE exist as a solid solution in combustion residues. Between 14.7% and 21.9% of Zn was recovered as OM-Zn in SS or AS, a higher percentage than other studies (Amir et al, 2005;Obrador et al, 2001), whereas relatively low amounts of Zn were found in the water-soluble and exchangeable fraction.…”