Minimization of hexavalent chromium in magnesite-chrome refractory
Document Type
Article
Publication Date
10-1997
Department
Department of Materials Science and Engineering
Abstract
The fundamentals on the formation of Cr6+ have been studied from two points of view: thermodynamic and kinetic. Thermodynamically, the CaO-Cr2O3 phase diagram can be used as a guide to understand the formation of Cr6+ as a function of temperature and composition. The Cr6+ content, in the CaO-Cr2O3 phase diagram, increases with exposure to temperatures below 1022 °C and with an increase in CaO (from 0 to 42 pet CaO). In kinetics, the chromite phase size also plays a major role in the formation of Cr6+. A decrease in chromite phase size increases the Cr6+ content in the refractory. The use of fused grains also decreases the formation of Cr6+. In the case of magnesite-chrome refractories, temperature, basicity (CaO/SiO2), and chromite phase size play important roles in Cr6+ formation. The formation of Cr6+ can be minimized by carefully controlling the amount of calcium oxide in the refractory and by avoiding the use of a fine chromite phase during brickmaking.
Publication Title
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Recommended Citation
Lee, Y.,
&
Nassaralla, C.
(1997).
Minimization of hexavalent chromium in magnesite-chrome refractory.
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science,
28(5), 855-859.
http://doi.org/10.1007/s11663-997-0013-7
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/5074