Fundamental Interactions of Glassy Carbon and Graphite with liquid Fe-C and Fe-Ti-C-N

The fundamental interactions of liquid iron with carbon, titanium, and nitrogen are at the heart of the blast furnace process, dictating productivity and longevity. The interactions of liquid Fe and C are particularly important in the hearth, with dissolution governing the properties of degradation of the carbonaceous hearth. When titanium and nitrogen are included in liquid Fe-C, Ti(C,N) can catalyze the solidification of an iron skull, further protecting refractory. Though a four-component system may seem simple, basic questions still need to be answered as to how these interactions affect the hearth refractory and, therefore, the campaign life of the blast furnace. A set of experiments is presented to illuminate how the formation of Ti(C,N) may protect the hearth. Graphite rods were dissolved into Fe-C containing Ti(C,N) but showed little difference in dissolution rate compared to rods dissolved without Ti(C,N). Rods with carbonaceous coatings doped with TiC, TiN, and Ti(C,N) were dipped into stagnant liquid Fe-C to test the propensity of dopants to assist in shell solidification. These experiments showed the importance of heat extraction to protecting the hearth. Micrographs of iron-carbon interfaces saw the majority of Ti(C,N) in large agglomerations away from the interface. The ability of Ti(C,N) to form these large agglomerations is likely the reason Ti additions are uniquely able to protect the hearth. The interactions of liquid Fe-C_sat and glassy carbon are also investigated to determine if glassy carbon is a suitable material for the hot face. Other experiments are documented to increase the utility of the high temperature confocal scanning laser microscope.