Hydrothermal processing of MSWI Fly Ash-towards new stable minerals and fixation of heavy metals

Bayuseno, A. P.; Schmahl, Wolfgang W. and Müllejans, Th. (2009): Hydrothermal processing of MSWI Fly Ash-towards new stable minerals and fixation of heavy metals. In: Journal of Hazardous Materials, Vol. 167, No. 1-3: pp. 250-259

Abstract

A hydrothermal processing strategy of MSWI fly ash is presented for obtaining stable minerals with low toxic potential. Different hydrothermal conditions were tested to obtain high yields of new stable minerals. Experimental parameters including temperature, nature and molarity of alkali reagents, and reaction time were evaluated. The chemical stability of hydrothermal products was examined by the toxicity characteristic leaching procedure (TCLP) test and subsequent XRD for the leached residue. The significant amounts of Al-substituted 11 Å tobermorite and katoite in addition to minor amounts of zeolites were formed under experimental conditions at 0.5 M NaOH, 180 °C for 48 h, however KOH treatment in a similar regime resulted in smaller amounts of Al-substituted 11 Å tobermorite and katoite. Similarly, a product of mixed Al-substituted 11 Å tobermorite and katoite could be formed from the washed fly ash treated in 0.5 M NaOH at 180 °C for 48 h. Under the acidic condition, the treated fly ash exhibited an excellent stability of the mineral assemblage and less release of heavy metals relative to the untreated parent materials.

• Item Type: Journal article
• Faculties: Geosciences > Department of Earth and Environmental Sciences > Crystallography and Materials Science
• Subjects: 500 Science > 550 Earth sciences and geology
• Language: English