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Incorporation of Chromium(III) and Chromium(VI) Oxides in a Simulated Basaltic, Industrial Waste Glass‐Ceramic
Author(s) -
Huang Deng,
Drummond Charles H.,
Wang Jue,
Blume Russell D.
Publication year - 2004
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2004.tb06358.x
Subject(s) - vitrification , chromium , spinel , leaching (pedology) , zirconolite , metallurgy , materials science , nuclear chemistry , augite , ceramic , mineralogy , chemistry , phase (matter) , geology , medicine , pyrochlore , quartz , organic chemistry , plagioclase , soil science , andrology , soil water
Chromium, an EPA listed toxic element concentrated in many industrial wastes, was stabilized using waste vitrification. Cr 2 O 3 and CrO 3 were loaded into a simulated basaltic base composition, vitrified, and cooled at various rates. Chromium incorporation mechanisms, vitrification processability, effect of initial Cr oxidation state, and product performance were investigated. At 1500°C, Cr 2 O 3 has a low solubility limit (0.54 wt%) in the base composition, and crystallized as Cr‐rich primary spinel (Mg,Fe)(Fe,Al,Cr) 2 O 4 . On cooling, Cr‐depleted secondary spinel and augite (Na,Ca)(Mg,Fe 2+ ,Al)(Si,Al) 2 O 6 crystallized. Cr(VI) was converted into Cr(III) on vitrification. The apparent viscosity of the melts was estimated using the Bottinga–Weill model as corrected by Roscoe's equation. The end products showed Cr 2 O 3 loading capacities as high as 16.7 wt% without exceeding the toxicity‐leaching limit defined by EPA. The annealed products had Vickers's hardness of about 800 kg·F/mm 2 and can be classified as medium‐grade abrasives.