Intrinsic Kinetics of Chlorination of WO3 Particles With Cl2 Gas Between 973 K and 1223 K (700 °C and 950 °C)

Micco, Georgina De; Bohé, Ana E.; Sohn, Hong Yong

doi:10.1007/s11663-010-9467-0

Cited by 11 publications

(7 citation statements)

References 18 publications

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“…In order to ensure good access of the reducing gas to the sample particles, a shallow crucible was used as sample holder. The total flowrate of reducing gas consisting of CO and CO 2 , was maintained at 1?5 NL min 21 , which was determined to be sufficient to eliminate the effect of gas flowrate for a gas-solid reaction of a similar rate (De Micco et al, 2011). The CO/CO 2 ratio of the gas mixture used in this study ranged from 10 : 90 to 40 : 60.…”

Section: Methodsmentioning

confidence: 99%

Kinetics of pre-reduction of manganese ore by CO

Gao

Kim

Sohn

2012

Mineral Processing and Extractive Metallurgy

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The degree of reduction of the higher oxides of manganese to the lowest oxide, MnO, achieved during the pre-reduction of manganese ore has a direct impact on the energy consumption for the subsequent smelting process. For ferruginous manganese ores, understanding the kinetics of pre-reduction is also useful for controlling the process parameters to optimise specific power consumption and maximise the metal recovery for upgrading by magnetic separation. The effects of reduction temperature, gas composition and particle size on the rate of reduction were investigated. Based on experimental results, the controlling step and activation energy for this reduction process were determined, and the rate expression was also developed.

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Section: Methodsmentioning

confidence: 99%

Kinetics of pre-reduction of manganese ore by CO

Gao

Kim

Sohn

2012

Mineral Processing and Extractive Metallurgy

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“…Using the described connections, it is now possible to analyze the total reaction in two ways: on one hand,

{normalα}_{{normalM}_{a} {Cl}_{b}}

can be calculated for different experimental conditions using experimental data and its dependence on the various reaction parameters can be investigated:

α = \frac{k_{e x p}}{p_{{C l}_{2}}} \cdot \sqrt{2 π R T M_{{C l}_{2}}} .

…”

Section: Quantitative Description Of Diffusion and Reaction Processesmentioning

confidence: 99%

Kinetics of volatilization of high temperature corrosion products and its application to chlorine corrosion

Rammer

Galetz

2016

Materials & Corrosion

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Operating atmospheres of many industrial high temperature processes contain a certain amount of halogens, in most cases chlorine. Halogens have the tendency of forming volatile metal chlorides of the general formula MxCly, which are well known to play a critical role in high temperature corrosion processes, when present at a significant amount. Thermodynamic calculations give a valuable hint, whether a reaction product can occur and how volatile such products can potentially be, when the partial pressures are calculated. However, such calculations reflect thermodynamically stable conditions, while in open systems the local kinetics control the process of surface reactions. For each specific condition, the reaction rates and thus the corrosion rates have to be determined. In previous work, we have shown that corrosion kinetics which lead to the formation of volatile products follows different steps. In this work, a mathematical model is developed in which the different steps, which are required for the formation of metal chlorides and their removal from the surface are described. It is assumed that the slowest of such formation or transport steps determines the kinetics of high temperature corrosion. The application of this model on the literature data shows that by this model it becomes possible to identify the slowest and therefore rate determining step.

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“…For corrosion product molecules which are not too large, such as volatile metal chloride molecules, the diffusion rate of molecular chlorine through the gas boundary layer can be assumed to be similar to that of the evaporating metal chlorides . Therefore the main question is if the diffusion processes are controlling the reaction rate, or if the chemical reaction between chlorine and the metal surface is the rate‐determining step.…”

Section: Reaction Mechanisms Of the High Temperature Chlorination Of mentioning

confidence: 99%

Refractory metals and nickel in high temperature chlorine‐containing environments ‐ thermodynamic prediction of volatile corrosion products and surface reaction mechanisms: a review

Galetz

Rammer

Schütze

2015

Materials & Corrosion

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Thermodynamic calculations are an important tool for prediction of chemical reactions. In many cases the results help to understand and describe the experimental observations. In others, especially if reaction kinetics play a major role, their predictive value can be rather limited and the projected results have to be treated with care. One such case are high temperature chlorine corrosion conditions. For example, thermodynamically a similar corrosion behavior of nickel and molybdenum is predicted in chlorine‐containing atmospheres at low oxygen partial pressures. In contrast to their calculated similarity, experimental results showed much higher resistance of molybdenum against the chlorinating attack. Above 800 °C nickel is rapidly consumed, whereas molybdenum remains almost inert. This paper reviews the literature on the corrosion mechanisms and kinetics of nickel and molybdenum in chlorine‐containing environments as well as in mixed oxygen‐chlorine‐containing atmospheres. Based on the literature review, differences in their reaction kinetics are discussed, taking into account the deviation from an ideal thermodynamic correlation between the partial pressure and the reaction kinetics via the often used Hertz‐Langmuir equation. Finally it is shown that the findings concerning the special characteristics of molybdenum and nickel and the conclusions drawn from experimental observations on high temperature chlorine corrosion can also be transferred to other metals.

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Intrinsic Kinetics of Chlorination of WO3 Particles With Cl2 Gas Between 973 K and 1223 K (700 °C and 950 °C)

Cited by 11 publications

References 18 publications

Kinetics of pre-reduction of manganese ore by CO

Kinetics of pre-reduction of manganese ore by CO

Kinetics of volatilization of high temperature corrosion products and its application to chlorine corrosion

Refractory metals and nickel in high temperature chlorine‐containing environments ‐ thermodynamic prediction of volatile corrosion products and surface reaction mechanisms: a review

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