title: Thermal Treatment of Chromium(III) Oxide with Carbonates Analyzed by Far-Infrared Spectroscopy.
abstract: The chemical state of thermochemically treated chromium(III) oxide (Cr2O3) with various carbonates was analyzed by far-infrared (far-IR) spectroscopy (spectral region 700-25 cm(-1)). Non-toxic Cr2O3 was oxidized with potassium, sodium, and calcium carbonate, respectively, to toxic Cr(VI) and Cr(V) compounds during thermal treatment at 1000 °C. In reverse, thermochemical treatment of Cr2O3 with magnesium carbonate lead to the formation of the Cr(III) compound MgCr2O4. Higher temperatures (>1200 °C) or reducing atmospheric conditions prevent the formation of Cr(VI)/Cr(V) compounds, too. Additionally, it was found that polyethylene powder with a low particle size (<70 μm) is favorable for the collection of good far-IR spectra of inorganic powders.
authors.affiliation: BAM Federal Institute for Materials Research and Testing, Division 4.4 Thermochemical Residues Treatment and Resource Recovery, Unter den Eichen 87, D-12205 Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Vogel
authors.forename: Jan
authors.initials: J
authors.lastname: Stemann
authors.forename: Karsten
authors.initials: K
authors.lastname: Holldack
authors.forename: Ryo
authors.initials: R
authors.lastname: Sekine
authors.forename: Ewelina
authors.initials: E
authors.lastname: Lipiec
authors.forename: Christian
authors.initials: C
authors.lastname: Adam