In the present study, the corrosion behaviour of several magnesia-chrome (MC) and
magnesia-alumina spinel (MA) bricks against fayalite type slags was investigated and the
role of the spinel phases was highlighted. The experimental results revealed that the
corrosion resistance of the MC bricks was superior to the MA bricks against KIVCET slags
in static and dynamic conditions. As a result of the interaction between MgO from MC
bricks and the slag, a modified forsterite phase (Mg, Fe, Zn, Ca) ���SiO��� was formed, which
destroyed the precipitated complex spinel bonds at the grain boundaries of periclase and
magnesia-chromia spinel. Furthermore, both MgO and MgO-MgAl���O��� spinel in the MA
brick dissolved into the slag, which resulted in modified forsterite phases of (Mg, Fe, Zn,
Ca)���SiO��� and (Mg, Fe, Zn)(Fe, Al)���0��� complex spinels, respectively. In addition, the
accretion formation in the KIVCET furnace was investigated through solubility experiments
of Cr���0��� in the KIVCET slag with various amounts of lead, which revealed that the net
contribution of Cr���03 to the spinel formation is the highest in the barren (no Pb) slag,
followed by high-lead (11% Pb) and it is the lowest for the low-lead (6% Pb) slag. The
amount of spinel solid solution increased consistently with increasing Cr���0��� dissolved and
the PbO existent in the slag.
From examinations of several used bricks from the tuyere area of a Peirce Smith nickel
converter, it was found that the corrosion is due to the interaction of the partially oxidized
matte penetrating deep into the brick and the magnesia grains forming (Mg, Fe, Ni, Co) XOy
spinels. Analyses of brick samples used in the KIVCET Electric Furnace roof identified
deep reaching sulphation, which weakened the bonding phase between coarse magnesia
grains. In the Bottom Blown Oxygen Converter, a highly aggressive lead and bismuth oxide
rich slag penetrated deep into the brick, which destroyed the grain boundaries, causing the
refractory to be easily eroded at the refractory-slag interface.
Our studies concluded that the spinel phases, either as magnesium chromate, magnesium
aluminate or complex spinel [(Mg, Fe)(Cr, Al, Fe) ���O���], enhanced the corrosion resistance of
a basic refractory to fayalite type slags from the non-ferrous smelting and converting
furnaces.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU./915 |
| Date | 05 1900 |
| Creators | Lo, Wai Man |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Format | 23303510 bytes, application/pdf |
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