Solution Loss Characteristics Of The Highlyreactive Cokes Prepared From Ca/Fe Additives In The H₂O@CO₂ Atmosphere

The hydrogen-rich blast furnace smelting is a clean and low-carbon iron-making technology.An understanding of the coke solution loss characteristics is of great significance for guiding the operation of hydrogen-rich blast furnace.The highly reactive cokes were prepared by addition of Ca/Fe additives to the blending coals,and the solution loss reactions of cokes in H₂O@CO₂ atmosphere were studied.The interactions between H₂O and CO₂ in coke solution loss reactions were analyzed to clarify the influence of Ca/Fe additive on the solution loss reaction characteristics of cokes.With the increase of H₂O content in the reaction atmosphere,the solution loss ratio of coke increases gradually.Also,the carbon loss ratio of Boudouard reaction decreases gradually and the carbon loss ratio of water gas reaction increases gradually,which shows that there is a strong competition of H₂O and CO₂ reactions with coke.Based on the difference of linear fitting slope between carbon solution ratio and H₂O content,the inhibition factorαwas proposed to characterize the inhibition degree of H₂O and CO₂reactions with coke.The analysis of the effects of Ca/Fe additives onα_CO2/H2O andα_H2O/CO2at different temperatures indicates that the catalysis of Ca additive primarily promote the water-gas reaction,but the catalysis of Fe additive mainly promoted the Boudouard reaction.The apparent activation energy of Boudouard reaction(E_CO2)and water gas reaction(E_H2O)for base coke are 154.2 and 89.8 k J·mol^–1 according to the coke solution loss rate at different temperatures.E_CO2 and E_H2O of Fe-coke are reduced by 3.7%and 13.7%,E_CO2 and E_H2O of Ca-coke are reduced by 13.7%and 18.8%,E_CO2 and E_H2O of BC+Ca&Fe coke are reduced by 16.8%and 21.3%.In H₂O@CO₂ atmosphere,E_CO2 and E_H2O were lowered by Ca/Fe additives.Also,ΔE of Ca-coke is greater thanΔE of Fe-coke,andΔE of BC+Ca&Fe coke is less than those of Ca/Fe-cokes,which indicates that the catalytic effect of Ca/Fe additive has significant difference and synergy.SEM-EDS and XRD analysis show that the contents of Fe₂O₃ in Fe-coke and Ca Al₂Si O₈ in Ca-coke are more than that in base coke,and Ca/Fe silicate compounds appeared in BC+Ca&Fe coke.Therefore,the Ca/Fe additives present the significant difference and synergy of catalytic effect.Figure 47;Table 22;Reference 59...