Abstract

Corundum-spinel castables containing lightweight aggregate has drawn many attention due to its potential for energy-saving, especially when applied in high-temperature region, such as the work lining of refining ladle. One main aspect that restricts its application is the slag corrosion performance, which is inferior when compared with traditional castables. In this study, one dense tabular corundum(denoted as TC) and two lightweight corundum(denoted as L1, L2) was chosen as aggregates to prepare three different corundum-spinel castables (denoted as CTC, CL1, CL2 respectively), and the slag resistance was compared through induction furnace corrosion test. XRD, SEM-EDS analyses, and thermodynamic and kinetics calculation was adopted for the discussion of corrosion mechanism. Results shown that the pore-size and its distribution, and the grain dimension of aggregates are importance for the slag performance, yet the effect of apparent porosity are not dominating. For castable CTC, the favorable corrosion resistance was mainly due to the larger average grain size of tabular corundum aggregates, of which the dissolution rate was slower when contacted with slag. The castable CL1 shown similar corrosion performance as CTC, which can be contributed to the relatively preferable microstructure of L1 - small pore size and no overlarge pore in the aggregates. The slag resistance of castable CL2 deteriorated as a result of the poor microstructure - larger pores and smaller grains of lightweight corundum L2.