Influence of adsorbed sulfur on surface reaction kinetics and surface self-diffusion on iron

Effect of Sulphur on Iron Carbide Formation and Stability.

“…Thus, the effect of surface-active sulphur on the catalytic activity of iron and the rate of topochemical reactions is well recognised. It was reported [1][2][3][4][5][6] that trace amount of sulphur significantly retarded cementite formation, free carbon deposition and cementite decomposition. In this paper, influence of sulphur on the iron carbide process was first investigated in the process of iron ore reduction by hydrogen.…”

Kinetics of Cementite Formation from Reduced Iron in CO-H2-H2S Mixtures under Pressurized Conditions

“…The reason why the value obtained in this study is much less than their value might be attributed to the difference in the physical properties of iron, i.e. iron foil with Grabke et al 26) and the very reactive iron with this study, which was iron reduced from iron oxide at the low temperatures with hydrogen Finally the carbide formation curves from reduced iron were simulated by applying the rate Eqs. (16) and (9), where the Eqs.…”

“…And the rate retarding effect of sulfur is well known with the reactions such as carburization, decarburization, nitrogenization, denitrogenization, the water gas shift reaction and so on which proceed on the surface of metals such as iron, nickel and so on. According to Grabke et al,26) the surface coverage of sulfur, q S , on metallic iron is expressed by a Langmuir adsorption isotherm and the coverage of vacant site, q ᮀ , is expressed by Eq. (15) (15) where K S is the adsorption coefficient of sulfur.…”

Sulfur Sorption Rate and Equilibrium Content of Reduced Iron in H2-H2S Mixtures

“…As a result, the present results were well expressed by the Langmuir's adsorption isotherm. Grabke 14) also applied the equation to represent the relation between the surface coverage of sulfur on an iron plate and sulfur activity in the atmosphere. They evaluated the surface coverage by analyzing the initial rate of carburization and nitrogenation on the surface of a high purity iron foil by the reactions with the atmospheres.…”

“…On the reactions on foil or plate of iron, especially, a number of studies were conducted by many authors including Yoshiwara et al [9][10][11][12] and Grabke et al [13][14][15][16] On the other hand, sulfur adsorption of the porous reduced iron particles has not studied at all because of the difficulties in the surface analysis of the porous iron in spite of its importance.…”