Chiang Mai Journal of Science

Ash content in coke has strong influence on the blast furnace operation since the ash largely affect not only carbon dissolution reaction but also wetting behavior of liquid iron on carbonaceous materials. However, role of the ash has been not concerned enough in the early stage which is determined as the first 300 seconds of contact period of the wetting. The aims of the study are to clarify effect of ash on the carbon dissolution reaction and the wetting behavior of two phases in the early stage using a new designed equipment. The equipment, sessile drop method with molten sample and rapid quenching systems, was be used to examine the wetting behavior and carbon dissolution reaction in the early stage. The results showed large effect of simulant ash on the carbon dissolution reaction and the wettability of the iron-carbon sample on the substrates in the early stage. The contact angle significantly decreased in the wetting of the sample on the substrate containing 0 and 10 vol% simulant ash in substrates. When the substrate contained 20 vol% simulant ash, the contact angle decreased in the contact period of 180 s, it then dramatically increased by 30^o to 134^o. The formation of simulant ash layer in the interface between the iron-carbon sample and the substrate containing 20 vol% simulant ash caused the contact angle to increase. In addition, the ash component was possibility to impede the carbon atoms diffusion from the substrate to the iron-carbon sample. Therefore, carbon dissolution rate decreased with increasing of the simulant ash content in the substrate.

Keywords:  molten sample injection system; rapid quenching system; carbon dissolution reaction; early stage; wetting behavior.