Reactions of Iron Pyrite: Its Thermal Decomposition, Reduction by Hydrogen and Air Oxidation

Schwab, G.-M.; Philinis, John

doi:10.1021/ja01203a007

Cited by 98 publications

(34 citation statements)

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“…The model equations can be used to explain the experimental literature data for similar systems. [7][8][9][10][11] Comparison between experimental results and calculated quantities for Q using the suggested model is shown in Figure 11. The first step to establish a simulation like that is the determination of the working column parameters.…”

Section: Linear Velocity Of the Fluid (µ)mentioning

confidence: 99%

Mathematical Simulation of Hazardous Ion Retention from Radioactive Waste in a Fixed Bed Reactor

Othman

Sohsah

Ghoneim

et al. 2006

Ind. Eng. Chem. Res.

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Reactor design for fluid-solid, noncatalytic reaction depends on the prediction of the performance of the reactor kinetically. Most mathematical models used to handle a fixed bed reactor in which the solid bed constitutes one of the reactants, while a second reactant is in the fluid phase, are complex and difficult to handle. A new mathematical model which is easier to handle has been developed to describe the system under investigation. The model was examined theoretically and experimentally. A column packed with a chelating cloth filter to separate radionuclides from radioactive waste solution is used as a practical application for the model. A comparison of the model predictions with the experimental results gives a satisfactory agreement at most of the process stages.

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Section: Linear Velocity Of the Fluid (µ)mentioning

confidence: 99%

Mathematical Simulation of Hazardous Ion Retention from Radioactive Waste in a Fixed Bed Reactor

Othman

Sohsah

Ghoneim

et al. 2006

Ind. Eng. Chem. Res.

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“…The apparent activation energy for the decomposition has been reported in the range of 120 to 275 kJ/mol. [1][2][3] The rate-determining step has been attributed by previous researchers to the dissociation of an anion, [1] the coordinated lattice destruction, [1] the S* 2 movement of the pyrite/pyrrhotite interface, [2] and gaseous diffusion. [3] The kinetics of the reduction of pyrite in H 2 has also been investigated by many researchers.…”

Section: Introductionmentioning

confidence: 97%

“…[3] The kinetics of the reduction of pyrite in H 2 has also been investigated by many researchers. [1,[4][5][6][7][8][9][10] They have reported apparent activation energies for the reduction between 70 and 200 kJ/mol. Most authors have reported that in the presence of H 2 , FeS 2 is converted to FeS with the production of H 2 S. Few authors have attempted to include the fact that FeS 2 is not converted directly to FeS and have neglected to account for the intermediate pyrrhotites which form during the reduction.…”

Section: Introductionmentioning

confidence: 99%

The kinetics and mechanism of the pyrite-to-pyrrhotite transformation

Lambert¹,

Simkovich

Walker

1998

Metall Mater Trans B

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The kinetics of the transformation of pyrite to pyrrhotite have been investigated. The study was performed using thermogravimetric analysis over the temperature range of 620 to 973 K in atmospheres of H 2 , He, Ar, and in vacuo over a wide range of pressures: 0.20 Pa to 4.24 MPa. Based on the kinetic results, a mechanistic picture of the various steps exerting control over the transformation is proposed. The thermal decomposition proceeds via a two-step, consecutive process. The ratecontrolling step is the desorption of sulfur vapor from the surface. The presence of H 2 introduces different rate-controlling steps into the sequence, providing the H 2 exists at a pressure sufficiently high to suppress the rate of thermal decomposition. Rates at which the H 2 reduction occurs with pyrite samples from different sources depends upon the samples' impurity level and the extent to which various crystallographic faces are exposed.

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“…We conclude that (I) the presence or absence of pyrite does not materially affect either the hydrogenation of organic sulfur or the uptake of hydrogen by the coal matrix as reflected in the organic sulfur and Btu changes, respectively; (2) nearly all the pyrite, when present in the coal samples (Experiments 2 and 4), is converted under the hydrogenation conditions to iron sulfide and hydrogen sulfide, as in the equation (3) as has been shown for mineral pyrite under similar conditions (Schwab and Philinis, 1947); and (3) the two coal samples, although from different coal basins, behaved similarly under hydrogenation conditions.…”

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confidence: 73%

Low-Sulfur Coal Obtained by Chemical Desulfurization Followed by Liquefaction

et al. 1976

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Coal combustion is the largest single source of sulfur oxide air pollution. Two major technologies for the desulfurization of coal prior to combustion, coal liquefaction and the Meyers Process, have been experimentally evaluated. While each process is individually capable of reducing a portion of U.S. coal reserves to an environmentally acceptable sulfur content, neither can meet all U.S. needs. An advantageous combination of the two processes is described which could eliminate a major technical hurdle in the application of liquefaction technology and thus expand the portion of U.S. coal which can be converted to an acceptably low-sulfur fuel. Information regarding the fate of sulfur forms during liquefaction is also presented.The sulfur content of coal, nearly all of which is emitted as sulfur oxide during combustion, is, on the average, about equally distributed between two chemical forms, inorganic (iron pyrites) and organic sulfur.An unconventional approach for near total removal of the pyritic sulfur content of coal has been reported by Meyers et al. (J 972). This new technique involves treatment of coal with a regenerable aqueous ferric solution, as outlined in the following equations (Hamersma et aI., 1973):

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Reactions of Iron Pyrite: Its Thermal Decomposition, Reduction by Hydrogen and Air Oxidation

Cited by 98 publications

References 0 publications

Mathematical Simulation of Hazardous Ion Retention from Radioactive Waste in a Fixed Bed Reactor

Mathematical Simulation of Hazardous Ion Retention from Radioactive Waste in a Fixed Bed Reactor

The kinetics and mechanism of the pyrite-to-pyrrhotite transformation

Low-Sulfur Coal Obtained by Chemical Desulfurization Followed by Liquefaction

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