Deuterium exchange studies of the interfacial rate of reaction of water vapor with silica-saturated iron silicate melts

A comprehensive kinetic model for the CO-CO2 reaction with iron oxide-containing slags

“…[15], [16], and [18] into Eq. [14] gives the rate as [20] where kЉ is a function of temperature only. It is worth pointing out that kЉ represents the true rate constant of the reaction, since the role of surfactants in surface poisoning of the melt is spontaneously included by using the surface concentration of reactive species, i.e., Fe 2ϩ .…”

“…[21], [17], and [20] into Eq. [4] yields the apparent rate-constant expression as [22] In order to compare the expression with the experimental results and to identify the rate-determining step of the reaction (between steps [10] and [11]), we may approximate the dependence of k a on r with Eq.…”

“…[1][2][3][4][5] Our knowledge of the kinetics and mechanism of such reactions has grown significantly since then. In particular, the reaction between CO-CO 2 [2,[6][7][8][9][10][11][12][13][14][15][16][17][18] and H 2 -H 2 O [19,20] with iron oxide in the slag have attracted considerable attention, owing to the significance of the reactions in a number of metallurgical processes including direct smelting of iron, electric steelmaking, and nonferrous metals refining. The reaction between the slag and CO-CO 2 atmospheres in its simplest form can be written as [1] with a general agreement between different studies that the rate of oxygen transfer with melts follows the form [2] In this equation, a o is defined as the CO 2 /CO ratio of the gas in the local equilibrium with the slag (with the unit CO 2 /CO as the standard state), and the apparent rate constant (k a ) has found to be a complex function of the bulk slag composition, a o , and temperature, rather than a simple temperature-dependent rate constant.…”

“…The rate expression (Eq. [20]) for this new situation, thus, becomes [26] The potential change at the surface upon replacement of iron ions with a more basic cation can be expressed with respect to the difference between the dipole moment of two molecules using the Helmholtz equation: [38] [27] where N is the number of replaced molecules per unit area, ⌬ is the difference between the dipole moments of two molecules, and °is the permittivity of free space.…”

Interfacial kinetics of hydrogen with liquid slag containing iron oxide

“…This could be confirmed by investiin our previous work, [3,4] and the calculated overall reduction gating the isotope exchange rate on liquid Fe t O using heavy rate are also presented in Figure 8 for comparison. Because water, [18] which is the subject of our future work. the concentration gradient of H 2 in the stagnant gas film decreases with decreasing the activity of Fe t O, the rate of V. COMPARISON WITH THE OTHER gas-phase mass transfer becomes slower with increasing REDUCING AGENTS additive content.…”