Kinetics and mechanism of arsenopyrite leaching in nitric acid solutions in the presence of pyrite and Fe(III) ions

Rogozhnikov, D. A.; Karimov, К. A.; Shoppert, Andrei; Dizer, Oleg; Набойченко, С. С.

doi:10.1016/j.hydromet.2020.105525

Cited by 33 publications

(16 citation statements)

References 46 publications

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“…However, their R 2 values were not close to one, making them unfit descriptions of the reaction. This could be attributed to This kinetic model agreed with the work by Rogozhnikov et al [5], who investigated the kinetics of the dissolution of refractory sulphidic gold-containing concentrated ore in nitric acid solution in the temperature range of 70-85 • C. It was also in agreement with the more recent work by this group on the effect of pyrite and ferric ions on the kinetics of arsenopyrite leaching in nitric acid solution [1]. Moreover, the research by Li et al [32] on the kinetics of cerium leaching from a mixed rare earth concentrate with nitric acid was also described by the new version of the shrinking core model based on the interfacial transfer and diffusion through the product.…”

Section: Kinetic Modelsupporting

confidence: 90%

“…To fulfil the high demand for gold, owing to its versatile applications, extracting gold from low-grade and more challenging gold ores is desirable. Many of these sources are refractory in nature: they are not amenable to conventional cyanidation [1,2]. In general, three factors can contribute to making a gold ore refractory: (1) Very fine gold particles (<10 µm) enclosed in impermeable gangue minerals, often sulphides; such fine gold cannot be adequately liberated, even with fine grinding, and so remain inaccessible to the leaching solution.…”

Section: Introductionmentioning

confidence: 99%

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The Kinetics of Pyrite Dissolution in Nitric Acid Solution

et al. 2022

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Refractory sulphidic ore with gold captured in pyrite has motivated researchers to find efficient means to break down pyrite to make gold accessible and, ultimately, improve gold extraction. Thus, the dissolution of pyrite was investigated to understand the mechanism and find the corresponding kinetics in a nitric acid solution. To carry this out, the temperature (25 to 85 °C), nitric acid concentration (1 to 4 M), the particle size of pyrite from 53 to 212 µm, and different stirring speeds were examined to observe their effect on pyrite dissolution. An increase in temperature and nitric acid concentration were influential parameters to obtaining a substantial improvement in pyrite dissolution (95% Fe extraction achieved). The new shrinking core equation (1/3ln (1 − X) + [(1 − X)−1/3 − 1)]) = kt) fit the measured rates of dissolution well. Thus, the mixed–controlled kinetics model describing the interfacial transfer and diffusion governed the reaction kinetics of pyrite. The activation energies (Ea) were 145.2 kJ/mol at 25–45 °C and 44.3 kJ/mol at higher temperatures (55–85 °C). A semiempirical expression describing the reaction of pyrite dissolution under the conditions studied was proposed: 1/3ln(1 − X) + [(1 − X)−1/3 − 1)] = 88.3 [HNO3]2.6 r0−1.3 e−44280/RT t. The solid residue was analysed using SEM, XRD, and Raman spectrometry, which all identified sulphur formation as the pyrite dissolved. Interestingly, two sulphur species, i.e., S8 and S6, formed during the dissolution process, which were detected using XRD Rietveld refinement.

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Section: Kinetic Modelsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

The Kinetics of Pyrite Dissolution in Nitric Acid Solution

et al. 2022

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“…In this case, FeS 2 acts as an alternative surface, as shown in Figure 14. This effect was observed in the studies of joint nitric acid leaching of arsenopyrite and pyrite [52]. Based on the SEM images and EDX mappings presented in Figures 11 and 12, as well as preliminary experiments presented in Figure 7, it can be concluded that during nitric acid leaching, the surfaces of copper minerals are passivated by a film of elemental sulfur.…”

Section: Characteristics Of the Received Cakessupporting

confidence: 53%

Nitric Acid Dissolution of Tennantite, Chalcopyrite and Sphalerite in the Presence of Fe (III) Ions and FeS2

et al. 2022

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This paper describes the nitric acid dissolution process of natural minerals such as tennantite, chalcopyrite and sphalerite, with the addition of Fe (III) ions and FeS2. These minerals are typical for the ores of the Ural deposits. The effect of temperature, nitric acid concentration, time, additions of Fe (III) ions and FeS2 was studied. The highest dissolution degree of sulfide minerals (more than 90%) was observed at a nitric acid concentration of 6 mol/dm3, an experiment time of 60 min, a temperature of 80 °C, a concentration of Fe (III) ions of 16.5 g/dm3, and an addition of FeS2 to the total mass minerals at 1.2:1 ratio. The most significant factors in the break-down of minerals were the nitric acid concentration, the concentration of Fe (III) ions and the amount of FeS2. Simultaneous addition of Fe (III) ions and FeS2 had the greatest effect on the leaching process. It was also established that FeS2 can be an alternative catalytic surface for copper sulfide minerals during nitric acid leaching. This helps to reduce the influence of the passivation layer of elemental sulfur due to the galvanic linkage formed between the minerals, which was confirmed by SEM-EDX.

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“…According to the analysis of the kinetic curves and the microstructure of the material, it is appropriate to perform a kinetic description of the process using the shrinking core model (SCM). Table 4 presents kinetics equations that were applied to describe the liquid–solid reaction [ 31 , 35 , 36 ]…”

Section: Resultsmentioning

confidence: 99%

Hydrothermal Treatment of Arsenopyrite Particles with CuSO4 Solution

Kritskii

Набойченко

2021

Materials

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The nature of the hydrothermal reaction between arsenopyrite particles (FeAsS) and copper sulfate solution (CuSO4) was investigated in this study. The effects of temperature (443–523 K), CuSO4 (0.08–0.96 mol/L) and H2SO4 (0.05–0.6 mol/L) concentrations, reaction time (1–120 min), stirring speed (40–100 rpm) and particle size (10–100 μm) on the FeAsS conversion were studied. The FeAsS conversion was significant at >503 K, and it is suggested that the reaction is characterized by the formation of a thin layer of metallic copper (Cu0) and elemental sulfur (S0) around the unreacted FeAsS core. The shrinking core model (SCM) was applied for describing the process kinetics, and the rate of the overall reaction was found to be controlled by product layer diffusion, while the overall process was divided into two stages: (Stage 1: mixed chemical reaction/product layer diffusion-controlled) interaction of FeAsS with CuSO4 on the mineral’s surface with the formation of Cu1+ and Fe2+ sulfates, arsenous acid, S0, and subsequent diffusion of the reagent (Cu2+) and products (As3+ and Fe2+) through the gradually forming layer of Cu0 and molten S0; (Stage 2: product layer diffusion-controlled) the subsequent interaction of CuSO4 with FeAsS resulted in the formation of a denser and less porous Cu0 and S0 layer, which complicates the countercurrent diffusion of Cu2+, Cu1+, and Fe2+ across the layer to the unreacted FeAsS core. The reaction orders with respect to CuSO4 and H2SO4 were calculated as 0.41 and −0.45 for Stage 1 and 0.35 and −0.5 for Stage 2. The apparent activation energies of 91.67 and 56.69 kJ/mol were obtained for Stages 1 and 2, respectively.

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Kinetics and mechanism of arsenopyrite leaching in nitric acid solutions in the presence of pyrite and Fe(III) ions

Cited by 33 publications

References 46 publications

The Kinetics of Pyrite Dissolution in Nitric Acid Solution

The Kinetics of Pyrite Dissolution in Nitric Acid Solution

Nitric Acid Dissolution of Tennantite, Chalcopyrite and Sphalerite in the Presence of Fe (III) Ions and FeS2

Hydrothermal Treatment of Arsenopyrite Particles with CuSO4 Solution

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