The application of reflected light microscopy, scanning electron microscopy-energy dispersive spectroscopy, Auger electron spectroscopy and electron microprobe analysis to the study of dusts

Conference · Mon Mar 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5096410

Hagni, A M; Hagni, R D ^[1]

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1. Univ. of Missouri, Rolla, MO (United States). Dept. of Geology and Geophysics

Over 500,000 tons of electric arc furnace (EAF) dust is generated each year in the US. The mineralogy and characterization of this dust is being studied to determine the phases and relationships of the valuable zinc, the hazardous lead, cadmium, and chromium, and the deleterious chlorine and fluorine. EAF dust averages 15--20% zinc and is therefore a potential source for 100,000 tons of zinc per year. The major mineralogical phases of EAF dust are franklinite (ZnFe[sub 2]O[sub 4]), magnetite (FeFe[sub 2]O[sub 4]), jacobsite (MnFe[sub 2]O[sub 4]), solid solutions between franklinite-magnetite-jacobsite, and zincite (ZnO). Franklinite, magnetite, and jacobsite solid solutions commonly are cruciform or dendritic crystals in a Ca-Fe-Si matrix and contain up to 5% chromium. Magnetite also occurs as spheres partially oxidized to hematite (Fe[sub 2]O[sub 3]) along its octahedral planes. The dust particles are predominantly in the form of spheres and broken spheres, ranging in size from 200 [mu]m to less than 1 [mu]m. Although many spheres are in the size ranges of 40--50 [mu]m and 10--20 [mu]m, most are less than 1 [mu]m in diameter. Automated scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) probed 118 particles in search of chlorine phases. Chlorine-bearing lime (CaO) was identified by that SEM study. In addition, chlorine is present as hydrophylite (CaCl[sub 2]) and sylvite (KCl). Auger electron spectroscopy (AES) was used to sputter the outer 180[angstrom] layer of the dust particles to search for the possible presence of cotunnite (PbCl[sub 2]) coatings, but none were detected. Minor phases detected include chalcopyrite (CuFeS[sub 2]), sphalerite (ZnS), pyrite (FeS[sub 2]), and coke.

• OSTI ID: 5096410
• Report Number(s): CONF-9303210-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:3; Conference: 27. annual Geological Society of America (GSA) North-Central Section meeting, Rolla, MO (United States), 29-30 Mar 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
37 INORGANIC
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DUSTS
CHEMICAL COMPOSITION
MINERALOGY
MATERIALS RECOVERY
SOLID WASTES
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