Control regimes and particle temperature gradients during decomposition of pyrites

Guha, B.K.; Narsimhan, G.

doi:10.1016/0300-9467(72)85016-0

Cited by 3 publications

(3 citation statements)

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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%

“…[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. [1,[4][5][6][7][8][9][10] They have reported apparent activation energies for the reduction between 70 and 200 kJ/mol.…”

Section: Introductionmentioning

confidence: 97%

“…[11][12][13][14] Another, somewhat more plausible, mechanism has been suggested by Niwa et al: [10] FeS ϩ H --FeS ϩ H S [3] which appeared. They further concluded that the second reaction was rapid compared to the other two, since no FeS appeared when FeS 2 was present.…”

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

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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