Journal of the Southern African Institute of Mining and Metallurgy
On-line version ISSN 2411-9717
MULLER, A.. The influence of slag basicity and composition on ConArc magnesia-carbon refractories during the blowing phase. J. S. Afr. Inst. Min. Metall. [online]. 2011, vol.111, n.4, pp. 225-230. ISSN 2411-9717.
The magnesia-carbon refractories used in the ConArc process experience severe wear as a result of the varying slag composition during the blowing phase. This work determines the basicity range in which minimum as well as maximum refractory wear was experienced by the magnesia-carbon refractories during service. In order to determine an optimum slag composition, the crucible test in an induction furnace was used. The magnesia-carbon refractory bricks were cut into cylindrical crucibles to which a synthetic slag in the form of pellets was added. The basicity (B2) of the slag was varied from 0.5 to 3. Tests were done at 1 600°C for one hour. Apart from the crucible test in an induction furnace, visual inspection and SEM analysis were also done to investigate the corrosion mechanism. FACTSage®predictions about the interaction between refractories and slag were also done. These predictions were compared to the actual results attained. It was found that the extent of corrosion by slag attack decreases as the basicity increases. The most severe corrosion of the MgO-C refractories occurred at a basicity of 0.5 whereas the optimum basicity is above 2.0. SEM analysis indicated severe slag attack at the lower basicities with no visible refractory-slag interaction at higher basicities. The FACTSage®predictions supported most of the actual findings.
Keywords : Magnesia-carbon; ConArc; blowing phase; slag resistance; induction furnace; crucibles.