title: Wet extraction of heavy metals and chloride from MSWI and straw combustion fly ashes.
abstract: Fly ash residues from combustion often do not meet the criteria neither for reuse as construction materials nor landfilling as non-hazardous waste, mainly because of the high concentration of heavy metals and chlorides. This work aimed to technically evaluate an innovative wet treatment process for the extraction of chloride (Cl(-)), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) from fly ashes from a municipal solid waste incineration (MSWI) plant and from a straw combustion (SC) facility. Factors investigated were liquid/solid (L/S) ratio, full carbonation (CO(2) treatment), influence of pH and leaching time, using a two-level full factorial design. The most significant factor for all responses was low pH, followed by L/S ratio. Multiple linear regression models describing the variation in extraction data had R(2) values ranging from 58% to 98%. An optimization of the element extraction models was performed and a set of treatment conditions is suggested.
authors.affiliation: Hamburg University of Technology, Institute of Environmental Technology and Energy Economics, Eissendorfer Street 40, D-21073 Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Aguiar del Toro
authors.forename: W
authors.initials: W
authors.lastname: Calmano
authors.forename: H
authors.initials: H
authors.lastname: Ecke
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide / Q000032:analysis; D005591:Chemical Fractionation / Q000379:methods*; D002712:Chlorides / Q000032:analysis / Q000302:isolation & purification*; D060729:Coal Ash; D006863:Hydrogen-Ion Concentration; D017745:Incineration; D007700:Kinetics; D019216:Metals, Heavy / Q000032:analysis / Q000302:isolation & purification*; D008956:Models, Chemical; D052638:Particulate Matter / Q000737:chemistry*; D018505:Waste Management / Q000379:methods*
chemical_list: D002712:Chlorides; D060729:Coal Ash; D019216:Metals, Heavy; D052638:Particulate Matter; D002245:Carbon Dioxide; D002244:Carbon