In Situ Observation and Reaction Mechanism of Iron Oxide Catalyst added to Coke

The performance of coke in blast furnace (BF) used to prefer a high strength and low reactivity, generally, while the high reactivity coke commonly has a low strength. To overcome the contradiction, it is important to develop a catalyst to increase the reactivity of carbon, so that the reaction mode can be changed from chemical reaction control to diffusion control. In this study, the reaction behavior of a ferro-coke was investigated, in which an iron oxide were added into a raw coal. Using high temperature laser microscope, in situ observation was carried out with the ferro-coke sample ground into tetragonal shape with 3.4 x 3.4 x 2.2 mm. Behavior of catalyst in coke was clarified through the in situ observations. It was found that the temperature at peak of reaction without catalyst was 1270 degrees C, while the coke with catalyst showed two peaks at 900 degrees C and 1270 degrees C. It was considered that redox reactions would exist in the system. The mechanism of redox reaction is shown as Eqs. (1), (2) and (3), mainly. FeO(melt) + C = Fe + CO (1) FeO(melt) + CO= Fe +CO2 (2) Fe + CO2 = FeO(melt) + CO (3) On the other hand, the coke gasification was analyzed using high precision mu-X-ray CT. The optimum conditions for the image processing of data from the mu-X-ray CT were obtained through the comparison with the cross section image of the coke embedded in the resin. Because of the smaller sample than the previous study, higher precision analysis was able to carry out.