Abstract:
The purpose of the study presented here is to determine to what extent chemical reactions
between carbon-based refractory and slag or metal in the tap-hole of a SiMn furnace can
contribute to wear of tap-hole refractory. The results of the study are reported in two parts. In
Part I, thermodynamic calculations suggested that reaction between silicomanganese slag and
carbon-based tap-hole refractory is possible, and experiments with nominally pure materials
support this. However, practical refractory materials are by no means pure materials and
contain secondary phases and porosity which can be expected to affect reaction with slag. In
Part II, such reactions are examined experimentally, in cup and wettability tests, using commercially
available carbon block and cold-ramming paste refractory materials and mainly
industrial SiMn slag. Clear evidence was found of chemical reaction at approximately 1870 K
(approximately 1600 C), forming SiC and, it appears, metal droplets. Both carbon block and
ramming paste refractory reacted with slag, with preferential attack on and penetration into the
binder phase rather than aggregate particles. The two types of carbon-based refractory materials
showed similar extents of chemical reaction observed as wetting and penetration in the laboratory
tests. The differences in refractory life observed practically in industrial furnaces should
therefore be attributed to wear mechanisms other than pure chemical wear as studied in this
work.
