Regenerative Energie

Biogas

Biomasse

Erneuerbare allgemein

Energieeinsparung

Erdwärme

Grünes Geld

Klimaschutz

Kraft-Wärme-Kopplung

Meeresenergie

Mobilität

Photovoltaik

Solarthermie

Wärmepumpen

Wasserkraft

Windenergie

content-Partner

Hydrothermal Solution of Heavy Metals from MSWI Fly Ashes

The solid residues produced during municipal solid waste incineration (MSWI) may be grouped into bottom ashes and fly ashes, which contain appreciable amounts of Fe and non-iron (NE) metals as well. Pure metals like Fe, Al or Cu can be separated from the bottom ashes by physical methods but there are no attempts to extract NE metals which are incorporated in oxide, chloride
or silicate mineral phases like Zn and Pb. In MSWI bottom ashes the Zn- and Pb contents vary from 2000 ppm up to 7000 ppm and 1000 ppm up to 3500 ppm, respectively.

The fly ashes were usually collect by filters like electrostatic precipitator (ESP). In ESP residues the Zn- and the Pb contents are much higher covering a range from 5000 ppm up to 100000 ppm for Zn and from2500 ppm up to 25000 ppm for Pb, respectively. Due to the high concentration of heavy metals as well as trace amounts of organic pollutants (dioxins, furans) the ESP residues are classified as hazardous material. In the last years a paradigm change took place. Now hazardous material becomes a resource for the heavy metals if the organic pollutants can be destroyed. A promising technique is the hydrothermal solution, transport and precipitation leading to separation and enrichmentof heavy metal compounds. In addition dioxins and furans were destroyed in the presence of an oxy-hydrous vapor phase. The yellowish material exists of spherical glass droplets of ca. 100 μm diameter, condensed alkali-chlorides and black carbon particles. Some of the glassdroplets are devitrified forming gehlenite, clinopyroxene and spinel. The grain size Distribution shows a polymodal shape. With d10 at 1 μm and d50 at 128 μm. The Zn- and Pb-content of the investigated ESP residues are 42071 ppm for Zn and 26380 ppm for Pb as determined by X-RayFluorescence Analysis (XRF). The Zn- and Pb-bearing mineral phases were characterized by XRay Powder Diffraction (XRPD) and Electron Microprobe Analysis (EMPA).

Copyright:	© Lehrstuhl für Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben
Quelle:	Depotech 2014 (November 2014)
Seiten:	1
Preis:	€ 0,00
Autor:	Amanda Günther
	Artikel nach Login kostenfrei anzeigen
	Artikel weiterempfehlen
	Artikel nach Login kommentieren

---