Pyrite oxidation kinetics in an oxygen–nitrogen atmosphere at temperatures from 400 to 500°C

Aracena, Álvaro; Jerez, Óscar; Ortíz-Soto, Rodrigo; Morales, Jaime W.

doi:10.1080/00084433.2015.1126904

Cited by 9 publications

(7 citation statements)

References 8 publications

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“…The curves obtained at 500, 600, and 800°C reach a maximum value of 0.33 weight loss fraction. This same value was recorded in previous work (Aracena, 2016b). The theoretical weight loss fraction represents the complete oxidation of pyrite to hematite, according to reaction (2).…”

Section: Pyrite Reaction Mechanisms For Temperature Above 500°csupporting

confidence: 65%

“…The theoretical weight loss fraction represents the complete oxidation of pyrite to hematite, according to reaction (2). However, for the case of temperatures higher than 500°C, two different slopes can be observed before reaching complete oxidation, a case that was not observed in the curve at 500°C, nor in the previous study (Aracena, 2016b). These curves have slope changes close to a value of 0.23 in weight loss fraction and then reach a maximum value of 0.33.…”

Section: Pyrite Reaction Mechanisms For Temperature Above 500°cmentioning

confidence: 50%

“…The same is presented with the theoretical fraction of oxidation of pyrite to hematite (reaction 2) which goes to a value of 0.33. This reaction would be the overall pyrite roasting process, also reported by Aracena (2016b), for temperatures below 500°C.…”

Section: Pyrite Reaction Mechanisms For Temperature Above 500°cmentioning

confidence: 52%

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Mechanism and kinetics of pyrite transformation at elevated temperatures

Aracena¹,

Jerez²

2021

Physicochem. Probl. Miner. Process.

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Pyrite (FeS2) is known as a sulfide that provides energy for various pyrometallurgical processes (fusion and conversion). There are several studies related to the evaluation of pyrite oxidation mechanisms at high temperatures, obtaining discrepancies in the products generated. In our work, the novelty of our research would be to obtain the thermochemical oxidation mechanism of FeS2 by using conventional thermogravimetric methods. The oxidative roasting of pyrite from 550 to 800°C was analyzed for an oxygen concentration of 5.07 to 28.06 kPa of oxygen and particle size between 12.3 to 33.8 microns. The results showed that the pyrite proceeded by sequential roasting: first, it produced an intermediate compound, pyrrhotite (Fe7S8), which was later oxidized to generate hematite (Fe2O3), both stages validated by weight loss of the sample as well as by analysis by DRX. Each stage had a different roasting speed as it was also influenced differently by different parameters. The temperature and particle size favored the rate of pyrrhotite generation, and the oxygen concentration favored the rate of hematite formation. The first-order kinetic equation ln (1-XPy) represented the roasting of the first stage (FeS2 → Fe7S8), with a calculated activation energy of 70.1 kJ/mol. The order of reaction was 0.5 concerning the partial pressure of oxygen and inversely proportional to the initial particle radius.

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Section: Pyrite Reaction Mechanisms For Temperature Above 500°csupporting

confidence: 65%

Section: Pyrite Reaction Mechanisms For Temperature Above 500°cmentioning

confidence: 50%

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Mechanism and kinetics of pyrite transformation at elevated temperatures

Aracena¹,

Jerez²

2021

Physicochem. Probl. Miner. Process.

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“…An important aspect of the technology is the intensity of oxidative roasting of the copper ore, which determines the specific productivity of the fluidized bed furnace and temperature and duration of the process; for its evaluation, information on the chemistry, kinetics, and mechanism of roasting is needed. A lot of publications are devoted to these questions in relation to copper-nickel ores [14], copper [15][16][17][18][19][20][21][22][23][24][25][26][27], zinc [17,28,29], nickel [30,31], and copper-cobalt [32] concentrates, as well as individual sulfide minerals which are part of them: pyrite [33][34][35][36][37][38][39][40][41][42][43][44][45][46], marcasite [47], mackinawite [48], pyrrhotite [34,36,39,[49][50][51][52][53][54], chalcopyrite [36,47,…”

Section: Introductionmentioning

confidence: 99%

Kinetics of solid-state oxidation of iron, copper and zinc sulfide mixture

2023

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The kinetics of solid-state oxidation by air of iron, copper and zinc sulfide natural mixture, which is typical of the pyritic copper ores, is investigated. Using the high-temperature X-ray powder diffraction, thermogravimetry and differential scanning calorimetry, it was found that the process can be represented by five exothermic elementary reactions, corresponding to intensive burning of iron, copper and zinc sulfides, and two endothermic ones, associated with decomposition of copper and iron sulfates. Kinetic analysis is performed by Kissinger and Augis–Bennett methods, the model-free function mechanism was determined from y(α) master plots and iterative optimization of the kinetic parameters. The limiting steps of these reactions are nucleation and crystal growth, and the values of activation energy, pre-exponential factor and Avrami exponent are in the ranges of 140–459 kJ·mol–1, 1.41·104–3.49·1031 s–1, and 1.0–1.7, respectively. Crystallization is followed by an increase in the number of nuclei, which may be formed both at the interface and in the bulk of the ore particles, and crystal growth is one-dimensional and controlled by a chemical reaction at the phase boundary or diffusion. The results of the work can contribute to the development of theoretical ideas about the physicochemical transformations of pyritic ores and concentrates during pyrometallurgical operations.

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“…Several articles have been published on the combustion and explosion of a single sulfide mineral. Researchers generally believe that the combustion and explosion processes undergo two stages: thermal decomposition and oxidation; the thermal decomposition process is consistent with the reaction in an inert atmosphere (N 2 , He, and Ar) [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

The Thermal Decomposition Behavior of Pyrite-Pyrrhotite Mixtures in Nitrogen Atmosphere

Tian

Rao

et al. 2022

Journal of Chemistry

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To assess the thermal transformation process of common sulfide minerals in a nitrogen atmosphere, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and thermogravimetric mass spectrometry are employed to define the influence of the pyrrhotite content in pyrite-pyrrhotite mixtures (mixed minerals). The results indicate that an increase in pyrrhotite content decreases the temperature of the maximum mass loss rate of mixed minerals and reduces its mass loss. The solid-phase transformation of the thermal decomposition of mixed minerals is accelerated because the apparent activation energy of pyrrhotite is lower than that of pyrite and mixed minerals. However, the pyrrhotite makes the mixed minerals easier to sinter and agglomerate, which reduces the total volatilization amount of the gas product, S2; thus, the rate of mass loss decreases.

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Pyrite oxidation kinetics in an oxygen–nitrogen atmosphere at temperatures from 400 to 500°C

Cited by 9 publications

References 8 publications

Mechanism and kinetics of pyrite transformation at elevated temperatures

Mechanism and kinetics of pyrite transformation at elevated temperatures

Kinetics of solid-state oxidation of iron, copper and zinc sulfide mixture

The Thermal Decomposition Behavior of Pyrite-Pyrrhotite Mixtures in Nitrogen Atmosphere

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