title: Separation of heavy metals from salts in multicomponent gas by a two-stage dust collection technique.
abstract: A Pb and Zn separation method from salts (Na, K, and Cl) in a simulated multicomponent gas generated by the incineration fly ash melting is studied. The heavy metals are separated using a two-stage dust collection technique. A standard reagents mixture is volatilized by heating in a lab-scale reactor to generate the simulated multicomponent gas. The volatilized salts in the gas are condensed and collected by a filter at a high temperature (600-800 °C), allowing Pb and Zn to pass through the filter as gaseous species. The gaseous heavy metals are condensed by lowering their temperature to 100 °C and collected. The metal separation is promoted by elevating the temperature used in the first-stage dust collection to 800 °C and maintaining a reductive atmosphere in the reactor. Subsequently, a sequential chemical extraction is performed on the obtained materials to evaluate the metals leaching characteristics from the materials. In the separated salts to be landfilled, a portion of toxic metals such as Pb, Cd, As, and Cr remain as water-soluble compounds. The separated Pb and Zn, to be extracted and recovered with precipitation for the metal enrichment, can be extracted using water, acid (pH 3), or CH₃COONH₄ solution (1M).
authors.affiliation: Laboratory of Solid Waste Disposal Engineering, Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan; Headquarters for Innovative Society-Academic cooperation, Fukui University, Bunkyo 3-9-1, Fukui 910-8507, Japan. Electronic address: t-okada@u-fukui.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Okada
authors.affiliation: Laboratory of Solid Waste Disposal Engineering, Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Nishimoto
mesh_terms: D000085:Acetates / Q000737:chemistry; D000143:Acids / Q000737:chemistry; D000393:Air Pollutants / Q000737:chemistry*; D005591:Chemical Fractionation; D011232:Chemical Precipitation; D060729:Coal Ash / Q000737:chemistry*; D006358:Hot Temperature; D007854:Lead / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D015032:Zinc / Q000737:chemistry*
chemical_list: D000085:Acetates; D000143:Acids; D000393:Air Pollutants; D060729:Coal Ash; D014867:Water; D007854:Lead; D015032:Zinc; C018824:ammonium acetate