Thermodynamic analysis of the reactions of iron oxides: Dissolution in oxalic acid

Panias, Dimitrios; Taxiarchou, Maria; Douni, I.; Paspaliaris, Ioannis; Kontopoulos, A.

doi:10.1016/s0008-4433(96)00018-3

Cited by 14 publications

(16 citation statements)

References 12 publications

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“…We propose a Mn 2 O 3 dissolution mechanism that explains the negative orders for protons and positive orders for manganese ions [6]:…”

Section: Figure 4 Dependence Of the Extent Of Dissolution (α) Of Mn mentioning

confidence: 99%

“…To accelerate the etching of manganese alloys and optimise the dressing and leaching of manganese oxide ores, it is necessary to understand the mechanisms of these processes [1][2][3][4][5][6][7][8][9][10][11][12]. The most promising method of improving the effectiveness of the etching of manganese oxides is reductive dissolution by various complexing agents [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…The most promising method of improving the effectiveness of the etching of manganese oxides is reductive dissolution by various complexing agents [5][6][7][8][9][10]. However, the rate-limiting step has not been identified in most works on the reductive dissolution of oxides.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of Manganese Oxides Dissolution in Sulphuric Acid Solutions Containing Oxalic Acid

Artamonova¹,

Горичев²,

Godunov³

2013

ENG

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The kinetics of the interaction of MnO₂, Mn₂O₃, and Mn₃O₄, with sulphuric acid solutions and the effect of oxalic acid on this process are studied. As the sulphuric acid concentration is increased from 0.1 to 5 N, the dissolution rate of Mn₂O₃, Mn₃O₄ to MnO₂ and Mn²⁺ ions decreases, whereas it increases with the concentration of Mn²⁺ ions. Upon the addition of H₂O_x, the complete dissolution of Mn₃O₄ occurs more quickly. The reaction order with respect to the H⁺ and O _x^2-ions is +0.5 ± 0.1. A mechanism of MnO₂ dissolution promotion by O _x^2-is proposed. The dissolution rate was found to depend on the concentrations of MnHO_x^- ions and was highest at pH 1.6 ± 0.2. A rate law and mechanism are suggested for manganese oxides dissolution.

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“…We propose a Mn 2 O 3 dissolution mechanism that explains the negative orders for protons and positive orders for manganese ions [6]:…”

Section: Figure 4 Dependence Of the Extent Of Dissolution (α) Of Mn mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of Manganese Oxides Dissolution in Sulphuric Acid Solutions Containing Oxalic Acid

Artamonova¹,

Горичев²,

Godunov³

2013

ENG

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“…. The presence of these ions is strongly connected to the pH of the solution [20]. For example, as Panias et al [20] have demonstrated, oxalic acid is mainly undissociated at very acidic solutions (pH is close to zero).…”

Section: Introductionmentioning

confidence: 97%

“…Equations (19) and (20) are also known as the Avrami-Erofe'ev models, which have been found to be valid for α between 0.05 and 0.9. Number 2 or 3 on the exponent (in a general form, the exponent is n = β + λ) includes information about the number of steps involved in nucleus formation, β, and number of dimensions in which the nuclei grow, λ.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and Kinetic Studies of Dissolution of Hematite in Mixtures of Oxalic and Sulfuric Acid

Vehmaanperä

Salmimies

Häkkinen

2020

Mining, Metallurgy & Exploration

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The dissolution of iron oxides in mixtures of acids is fairly uncommon but can result in a more efficient dissolution process. The objective in this work was to investigate the dissolution of synthetic hematite powder in mixtures of oxalic and sulfuric acid. Experiments were done at different acid ratios and temperatures. An increase in temperature from 15 to 35 °C increased solubility, whereas an increase from 35 to 50 °C did not change the solubility but had a profound effect on the kinetics. An important finding was that oxalic acid advanced the dissolution process since increasing the amount of oxalic acid in the system resulted in faster kinetics and higher solubilities. The dissolution kinetics were well described with the Kabai model, which was the only studied model able to describe the whole reaction time. However, the solid specific constant a varied for the different acid ratios and this is argued to be a result of changes in the solid phase. The changes in the constant a were not in line with the original study of Kabai, which indicates that a cannot be the solid specific constant but it can be the constant connected to dissolving media describing the changes in the dissolution mechanism.

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Characterisation and catalytic activity in de-NOx reactions of Fe-ZSM-5 zeolites prepared via ferric oxalate precursor

Rivallan

Berlier

Ricchiardi

et al. 2008

Applied Catalysis B: Environmental

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Thermodynamic analysis of the reactions of iron oxides: Dissolution in oxalic acid

Cited by 14 publications

References 12 publications

Kinetics of Manganese Oxides Dissolution in Sulphuric Acid Solutions Containing Oxalic Acid

Kinetics of Manganese Oxides Dissolution in Sulphuric Acid Solutions Containing Oxalic Acid

Thermodynamic and Kinetic Studies of Dissolution of Hematite in Mixtures of Oxalic and Sulfuric Acid

Characterisation and catalytic activity in de-NOx reactions of Fe-ZSM-5 zeolites prepared via ferric oxalate precursor

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