Behaviors of Swelling and Reaction Gas Generation during Firing of Iron Oxide Briquettes Containing Coke, Coal and Charcoal

Abstract

The structural changes, characteristics of gas generation and build-up of internal gas pressure that occurred during the firing of hematite briquettes containing carbon materials, were studied by the swelling phenomenon analysis in the temperature range from room temperature to 1 150°C.
Generally, the primary swelling which occurred in a wide temperature range of 600900°C and secondary swelling which occurred at about 1 000°C could be clearly distinguished. The secondary swelling was considerably affected by kinds of the carbon materials containing in briquettes. The swelling occurred in briquette when it contained carbon materials with high density, namely coke, was not so large, but briquettes which contained carbon materials with small density, namely charcoal, show large swelling. The swelling was considerably affected by particle size of carbon materials.
From the results of effluent gas analysis, it was identified that an increase in rate of gas generation from briquettes occurred overlapping with secondary swelling and accelerated remarkably. That was produced. by the rapid increase in CO concentration of reaction gas. An increase in internal gas pressure of briquette occurred simultaneously. In the case of briquette containing 20% charcoal, the build-up of pressure values of about 0.5 kg/cm² was obtained.