Interparticle heterogeneity on semi-soluble matrices and surface of municipal solid waste incineration fly ash

Abstract

Japan produced about 43.17 million tons of municipal solid waste (MSW) in 2016 and 80.3% of their MSW treated by using incinerator. Around 74% of incinerator in Japan is stoker combustor, and 14% is fluidized bed type incinerator. Byproducts from incineration process are bottom ash and fly ash. Although municipal solid waste incineration (MSWI) fly ash is fine particles and has been regarded as homogeneous in many previous researches, it has not been proved based on sufficient analysis in the microscopic observation. Therefore, the objective of the study is to investigate elemental heterogeneity among fly ash particles (interparticle heterogeneity) on the surface and semi-soluble matrices generated from stoker and fluidized bed incinerator. Surface elemental concentrations of each fly ash particles, measured by SEM-EDS, were used to analyze elemental heterogeneity of fly ash particles. Regarding heterogeneity, all major elements in fly ash particles from both combustors had wide range of average concentration which can imply fly ash particles have elemental heterogeneity among itself. Fly ash from fluidized bed has more interparticle heterogeneity on the surface and semi-soluble matrices than fly ash of stoker incinerator. Both incinerators have interparticle heterogeneity on surface less than on semi-soluble matrices of MSWI fly ash particles.