Rate of Reduction of Liquid Wustite with CO

Abstract

The reduction rate of liquid wustite contained in an iron crucible under Ar-CO, CO-CO₂ or Ar-CO-CO₂ gas mixtures has been measured by using thermobalance at 1 400 and 1 450°C. The experimental region of partial pressure of CO was P_CO=0.02 -0.18 atm (Ar-CO) and P_CO=0.07-0.84 atm (Ar-CO-CO₂ and CO-CO₂).
The apparent reduction rate became constant in the region of gas flow rate above 2.5 l/min. Under this experimental condition, the rate of reduction was controlled by the chemical reaction at the interface, and was expressed by the following equation :
r=k_c(K_e-α)P_CO (g-oxygen/cm²·s),
where K_e and α are the equilibrium constant of the reaction among gas, liquid wustite and solid iron, and P_CO2/P_CO in the gas phase, respectively. The apparent rate constant of the chemical reaction, k_c, was expressed by the following equation :
k_c=1.18 exp(-24 300/RT) (g-oxygen/cm²·s·atm).
The reduction rate of liquid wustite with CO was 6 times larger than that of solid wustite.