Rates of MnO Reduction from Silicate Slags with Solid Carbon

Shimoo, Toshio; Ando, Soichiro; Kimura, Hiroshi

doi:10.2320/jinstmet1952.48.9_922

Cited by 10 publications

(24 citation statements)

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“…[19] The details of the Boudouard reaction in an experimental set up similar to this study have already been studied by the authors. [21] The slag reduction experiments are conducted under Ar gas flashing through the furnace chamber; thus, reactions [4] and [7] are probably not important. It is worth noting that if a CO-CO 2 gas film can exist locally at the slag/metal interface, then reactions [4] and [7] can take place with simultaneous reaction of the produced CO 2 with the dissolved carbon in the metal [reaction [8]].…”

Section: Chemical Reactionsmentioning

confidence: 99%

“…[21] The slag reduction experiments are conducted under Ar gas flashing through the furnace chamber; thus, reactions [4] and [7] are probably not important. It is worth noting that if a CO-CO 2 gas film can exist locally at the slag/metal interface, then reactions [4] and [7] can take place with simultaneous reaction of the produced CO 2 with the dissolved carbon in the metal [reaction [8]]. This means that reaction [3] involves subreactions [4] and [8], and reaction [6] involves subreactions [7] and [8].…”

Section: Chemical Reactionsmentioning

confidence: 99%

“…It is worth noting that if a CO-CO 2 gas film can exist locally at the slag/metal interface, then reactions [4] and [7] can take place with simultaneous reaction of the produced CO 2 with the dissolved carbon in the metal [reaction [8]]. This means that reaction [3] involves subreactions [4] and [8], and reaction [6] involves subreactions [7] and [8]. Regarding the point that the Boudouard reaction in the system is uncertain, the overall results of reactions [3] and [6] are considered in the discussions of this study.…”

Section: Chemical Reactionsmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12] These studies have been mainly conducted in graphite crucibles with or without an initial metal phase. Stirring has no significant effect on the kinetics of MnO reduction, whereas the reduction rate is affected by the slag composition and temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, it has been suggested that the reaction kinetics are not controlled by the diffusion of the components in the bulk of the metal and slag phases and that they are controlled by the chemical reactions. [1][2][3][4][5][6][7][8][9][10][11] Also, the kinetics of MnO reduction is affected by the gas phase composition and different MnO reduction rates occur when different inert gases are used. Hence, it has been proposed that the carbothermic reduction of MnO is a mixed-control reaction that controls both the chemical reaction and the CO mass transfer in the gas phase.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Kinetics and Mechanism of the Simultaneous Carbothermic Reduction of FeO and MnO from High-Carbon Ferromanganese Slag

Safarian

Kolbeinsen

Tangstad

et al. 2009

Metall Mater Trans B

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The carbothermic reduction of 38.7 pct MnO-12.1 pct pct MgO-9.3 pct Al 2 O 3 -24.1 pct SiO 2 -10.4 pct FeO slag in Ar at 1600°C was studied using the sessile drop wettability technique. Pure graphite, coke, and charcoal were used as the carbon material substrates. The reduction rates were evaluated by sampling at different reduction times and by analyzing the chemical compositions of the reduced slag and the produced metal. The carbothermic FeO reduction from slag is initially fast followed by a much slower reduction rate. However, the rate of the MnO reduction is slow in the fast FeO reduction stage, and it starts to increase significantly during the slow FeO reduction stage. The kinetics of FeO and MnO reduction are affected by the type of carbonaceous materials. Moreover, the rate of the carbon dissolution/transfer into the produced metal phase and the amount of the transferred manganese to the metal phase depend on the type of carbon. Based on the experimental observations and the thermodynamic calculations, a mechanism for MnO reduction was proposed. According to this mechanism, MnO is mainly reduced through a metallothermic reduction by Fe and the rate of MnO reduction is controlled by the rate of the consumption of FeO from the slag, which takes place simultaneously. In contrast, the rate of FeO reduction in the fast initial reduction stage is controlled by the rate of the carbon dissolution/transfer into the metal phase. However, at the second slow FeO reduction stage, it is reduced mainly by the solid carbon.

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Section: Chemical Reactionsmentioning

confidence: 99%