Determination of reducibility of iron and steel plant scale with coke

In this study, the reducibility of the steel plant scale sample of Kroman Çelik Sanayii A.Ş. under the influence of coke was investigated. Experiments were conducted using a metallurgical furnace which temperature can be adjusted to 1600° C. In this study, effects of temperature, binder ratio (Na-bentonite) and pellet diameter on reduction efficiency were investigated. According to the results, it was found that reduction efficiency increased with increasing temperature, decreased with pellet diameter increased and binder ratio has not significant effect on the reduction efficiency. Using kinetic evaluation, it was determined that the reducibility of steel plant scale under the influence of coke was compatible with the "shrinking core model". The determined model can be expressed as "1/3ln(1-X)-[1-(1-X)-1/3]=k_d t" The activation energy calculated in the temperature range of 900-1050 °C and 1050-1150 °C was found to be 444.77 kJ/mol and 24 kJ/mol, respectively. The effect of pellet diameter on reduction efficiency was determined as (d)-1,963. The semi-empirical model found using the diffusion model is presented follows. For the temperature range covering 900-1050 °C; 1/3ln(1-X)-[1-(1-X)-1/3]=kn.(e-444770/(R.T).(d)-1.963.(Na-bentonite content)1).t For the temperature range covering 1050-1150 °C; 1/3ln(1-X)-[1-(1-X)-1/3]=kn.(e-24000/(R.T).(d)-1.963.(Na-bentonite content)1).t Keywords: Reduction, Coke, Pellet, Sponge iron, Steel plant scale, Wustite