Effect of Synthesis Parameters on the Phase Formation in the System FeSO4-H2O-H+/OH--O2(3.5   pH   13)

Клещева, Регина Раисовна; Kleshchev, D. G.; Tolchev, A. V.; Popov, Mikhail; Pervushin, V. Yu.

doi:10.1023/b:rjac.0000012651.10582.83

Cited by 2 publications

(2 citation statements)

References 5 publications

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“…As a result, the average size of crystals decreases, their imperfections increase, and phases with disordered crystal structure are formed, in particular, δ-FeOOH. At the same time, it should be noted that our data for γ-Fe 2 O 3 phase formation do not agree with previous results [7,18] for the formation of the Fe 3 O 4 phase during the oxidation of Fe(OH) 2 suspensions by atmospheric air under analogous conditions (pH ≈ 9). This contradiction is eliminated if we assume that in our experiments the application of a more active oxidizer (H 2 O 2 ) originally leads to the formation of the Fe 3 O 4 phase in a nanodisperse state, which is subsequently oxidized by hydrogen peroxide to γ-Fe 2 O 3 by a topotactical solidstate reaction mechanism.…”

Section: Fig 2 the Average Crystal Size D (Nm) Of Phases Formed In contrasting

confidence: 53%

Nanodisperse oxide compounds of iron formed in the FeSO4 – KOH – H2O – H2O2 system (4.0 ≤ pH ≤ 13.0)

Жеребцов¹,

Мирасов²,

Kleschev³

et al. 2015

Nanosist.: fiz. him. mat.

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The regularities of phase formation during oxidation of aqueous solutions of FeSO 4 and (or) suspensions of Fe(OH) 2 at quasi-constant temperature and pH values have been studied for wide intervals of temperature (20 -85• C) and (4.0 -13.0) of the reaction medium. The produced nanodisperse materials have been examined by X-ray phase analysis, IR spectroscopy, scanning electron microscopy and X-ray fluorescence analysis, as well as by thermogravimetric analysis combined with thermal analysis and mass spectrometric analysis of released gases. The dependences of the phase, chemical and disperse compositions of the formed precipitates on the synthesis parameters have been revealed.

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Section: Fig 2 the Average Crystal Size D (Nm) Of Phases Formed In contrasting

confidence: 53%

Nanodisperse oxide compounds of iron formed in the FeSO4 – KOH – H2O – H2O2 system (4.0 ≤ pH ≤ 13.0)

Жеребцов¹,

Мирасов²,

Kleschev³

et al. 2015

Nanosist.: fiz. him. mat.

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“…Prior to each experiment, the LSR and balls were weighed according to the B/M and then transferred into the reactor vessel. Subsequently, the prepared water with a pH value of 4 was added, which could prevent the hydrolysis of iron ions and facilitate the separation of lead and iron. , After milling, the mixture was filtered and washed with deionized water. The sulfate in the leachate was determined via ion chromatography, and the proportion of lead sulfate and metallic lead in the dried residue was analyzed by the chemical titration method.…”

Section: Methodsmentioning

confidence: 99%

A Facile and Environmentally Friendly Approach for Lead Recovery from Lead Sulfate Residue via Mechanochemical Reduction: Phase Transformation and Reaction Mechanism

Che

Zhang

Liu

et al. 2021

ACS Sustainable Chem. Eng.

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Lead sulfate residue (LSR) is an important secondary lead resource also categorized as a hazardous waste, which has gained great attention in clean and sustainable utilization technology due to the shortage of primary resources and environmental pollution. The current methods for LSR treatment involve a potential environmental risk including emission of SO x gas and generation of waste acids and alkali. Herein, an environmentally friendly method is proposed for treating LSR, by which lead was reduced under ambient conditions via mechanical ball milling using iron powder as the reductant. The phase transformation of lead was analyzed by X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectrometry, Fourier transform infrared, and X-ray photoelectron spectroscopy, revealing that the reduction time, rotation speed, mass ratio of ball to material (B/M), and iron powder dosage positively influenced the reduction of lead sulfate. The highest lead sulfate reduction efficiency of 99.9% was obtained under optimum conditions: rotation speed of 300 rpm, reduction time of 2 h, B/M of 15 g/g, and 1.5 times the theoretical dosage of iron powder. The generated ferrous sulfate was subsequently removed by water washing, and excess iron powder was separated by melting, accompanied by metallic lead produced with a high purity of 99.2%. This process is simple and environmentally friendly, showing good potential for industrial application.

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Effect of Synthesis Parameters on the Phase Formation in the System FeSO₄-H₂O-H⁺/OH^--O₂(3.5 pH 13)

Cited by 2 publications

References 5 publications

Nanodisperse oxide compounds of iron formed in the FeSO4 – KOH – H2O – H2O2 system (4.0 ≤ pH ≤ 13.0)

Nanodisperse oxide compounds of iron formed in the FeSO4 – KOH – H2O – H2O2 system (4.0 ≤ pH ≤ 13.0)

A Facile and Environmentally Friendly Approach for Lead Recovery from Lead Sulfate Residue via Mechanochemical Reduction: Phase Transformation and Reaction Mechanism

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