Kinetics of Roasting of a Sphalerite Concentrate

Marzoughi, O.; Halali, Mohammad; Moradkhani, Davood; Pickles, C.A.

doi:10.1007/978-3-319-95022-8_44

Cited by 2 publications

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References 15 publications

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“…According to the literature data, the effective activation energy of the processes accompanying the oxidation (when heated in air) of iron, copper, and zinc sulfides, as well as their natural and artificial mixtures of various sizes (from -0.043 to -12 mm), can be of 7-463 kJ•mol -1 [11,14,19,26,27,40,41,53,60,67,69,72,82,85]; the estimates obtained in this work (E r j = 124-455 kJ•mol -1 ) do not go beyond this range. The results of determining the reaction model show that the limiting step of all elementary oxidation reactions of the studied ore is nucleation and crystal growth.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%

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

2023

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Kinetics and mechanism of oxidizing roasting of sulfide copper-cobalt ore

Klyushnikov

Gulyaeva

Пикалов

et al. 2023

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The aim of the study was to examine the chemistry, kinetics and mechanism of oxidizing roasting of a typical sample of sulfide copper-cobalt ore. The research object was sulfide copper-cobalt ore with the following main minerals: pyrite, pyrrhotite, chalcopyrite, sphalerite, tremolite, silicon dioxide, talc, siderite and calcite. The methodology involved high-temperature X-ray phase analysis (100–900°C), thermogravimetry, differential scanning calorimetry and mass spectrometry of the released gas (30–1100°C, heating rate – 5–20°C·min-1, air flow rate – 30 cm3·min-1). The chemistry, kinetics and mechanism of oxidizing roasting of sulfide copper-cobalt ore with a particle size of <0.1 mm were studied. It was found that the process can be represented as a set of seven elementary reactions: five exothermic reactions (at 398–445, 394–488, 440–498, 433–549 and 451–562°C), corresponding to the intense combustion of iron, copper and zinc sulfides, and two endothermic reactions (at 651–664 and 743–927°C), associated with the decomposition of residual copper and iron sulfates. Kinetic analysis (Kissinger and Augis-Bennett methods, identification of the reaction model by reference function and iterative optimization) of differential scanning calorimetry data in connection with the above reactions showed that the limiting stage of the latter is nucleation and crystal growth. The values of activation energy, pre-exponential factor and Avrami parameter ranged between 140–459 kJ·mol-1, 1.41·104–3.49·1031 with-1 and 1.0–1.7, respectively. It was established that crystallization of the products of elementary reactions is accompanied by an increase in the number of nuclei; new phase nuclei can be formed both on the surface and in the bulk of ore particles. The crystal growth is one-dimensional and is controlled by a chemical reaction at the interphase boundary or by diffusion of reagents. The results obtained can be applied in the practice of oxidizing roasting of sulfide ores and concentrates.

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Kinetics of Roasting of a Sphalerite Concentrate

Cited by 2 publications

References 15 publications

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

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

Kinetics and mechanism of oxidizing roasting of sulfide copper-cobalt ore

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