The nucleation kinetics of ammonium metavanadate precipitated by ammonium chloride

Du, Guangchao; Sun, Zhanwen; Yu, Xiaoquan; Jing, Han; Chen, Haijun; Yin, Danfeng

doi:10.1016/j.jcrysgro.2016.02.016

Cited by 35 publications

(19 citation statements)

References 50 publications

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“…Figure b shows the transformations in crystal structure and phase purity of the samples examined through X‐ray diffraction (XRD) patterns (Rigaku D/MAX‐RB diffractometer equipped with a Cu Kα radiation source). The products can be indexed to the monoclinic (NH 4 ) 2 V 6 O 16 phase with the lattice constants a, b, c, α, β, and γ of 0.7858 nm, 0.8412 nm, 0.4995 nm, 90.00°, 96.43°, and 90.00°, respectively (ICSD collection code: 067282) …”

Section: Resultsmentioning

confidence: 99%

Efficient Microwave Irradiation‐Assisted Hydrothermal Synthesis of Ammonium Vanadate Flake

Wang

Zhang

Huang

et al. 2017

Crystal Research and Technology

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The major factors and affection for hydrothermal synthesis of ammonium vanadate in microwave irradiation was investigated and optimized. The obtained material was a pure (NH 4 ) 2 V 6 O 16 phase with regular spindle and rhombic crystal shapes. Transmission electron microscope and selected-area electron diffraction patterns confirmed that the microwave irradiation-assisted hydrothermal treatments altered the growth pattern and expanded the [-1 0 0] interplanar spacing by approximately ß8%-12% compared to the standard powder diffraction file data.

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Section: Resultsmentioning

confidence: 99%

Efficient Microwave Irradiation‐Assisted Hydrothermal Synthesis of Ammonium Vanadate Flake

Wang

Zhang

Huang

et al. 2017

Crystal Research and Technology

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“…where k is the reaction rate constant, Ea is the apparent activation energy (kJ/mol), R is the molar gas constant (J•mol −1 •K −1 ), T is the reaction temperature (K), and A is the constant. Finally, according to the relationship between the reaction rate constant (k) and temperature (T), the apparent activation energy E a of natroalunite and alunite were calculated using the Arrhenius formula (see Equation ( 8)) [28][29][30], as shown in Figure 10.…”

Section: 𝑙𝑛 𝑟 = 𝑙𝑛 𝑘 + 𝑚 𝑙𝑛[ 𝐶]mentioning

confidence: 99%

Controlled Hydrothermal Precipitation of Alunite and Natroalunite in High-Aluminum Vanadium-Bearing Aqueous System

et al. 2021

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During the acid leaching process of black shale, with the destruction of the aluminosilicate mineral structure, a large amount of aluminum (Al) is leached, accompanied by the release of vanadium (V). To separate aluminum from the vanadium-containing solution, the precipitation behavior of aluminum ions (Al3+) was investigated under hydrothermal conditions with the formation of alunite and natroalunite. In the solution environment, alunite and natroalunite are able to form stably by the Al3+ hydrolysis precipitation process at a temperature of 200 °C, a pH value of 0.4 and a reaction time of 5 h. When Al3+ was precipitated at a K/Al molar ratio of 1, the aluminum precipitation efficiency and the vanadium precipitation efficiency were 64.77% and 1.72%, respectively. However, when Al3+ was precipitated at a Na/Al molar ratio of 1, the precipitation efficiency of the aluminum decreased to 48.71% and the vanadium precipitation efficiency increased to 4.36%. The thermodynamics and kinetics results showed that alunite forms more easily than natroalunite, and the reaction rate increases with increasing temperature, and the precipitation is controlled by the chemical reaction. Vanadium loss increases as the pH value increases. It can be deduced that the ion state of tetravalent vanadium (VO2+) was transformed into the ion state of pentavalent vanadium (VO2+) in the hydrothermal environment. The VO2+ can be adsorbed on the alunite or natroalunite as a result of their negative surface charges, ultimately leading to vanadium loss.

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“…Conversely, should the critically-sized vapour bubble gain just a tiny amount of matter, taken away from the surrounding liquid, then the bubble will spontaneously grow, becoming detectable. In view of the mentioned relation between the value of the free enthalpy and the stability of a system that can be in more than one equilibrium state at constant T and p, such an extreme instability condition must correspond to a maximum of the difference between the free enthalpies of the superheated liquid and the stable vapour, or, that is the same, a maximum of the free enthalpy variation associated with the phase change, which is an approach also used in the study of crystal nucleation, see, e.g., [33][34][35][36]. The critical radius R c can then be regarded as the size of the vapour bubble corresponding to the maximum of the function which describes the free enthalpy variation ∆G(r) associated with the formation of a vapour bubble of radius r that nucleates in a metastable liquid kept at constant temperature T L and pressure p L ∆G(r) = ∆H(r) − T L ∆S(r), (3.3) which can also be written as the sum of a volume term ∆G vol (r) and a surface term ∆G surf (r) giving ∆G(r) = ∆G vol (r) + ∆G surf (r).…”

Section: Radius Of the Critically-sized Nucleated Vapour Bubblementioning

confidence: 99%

On the critical energy required for homogeneous nucleation in bubble chambers employed in dark matter searches

et al. 2019

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Two equations for the calculation of the critical energy required for homogeneous nucleation in a superheated liquid, and the related critical radius of the nucleated vapour bubble, are obtained, the former by the direct application of the first law of thermodynamics, the latter by considering that the bubble formation implies the overcoming of a barrier of the free enthalpy potential. Comparisons with the currently used relationships demonstrate that the sensitivity of the bubble chambers employed in dark matter searches can be sometimes notably overestimated.

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The nucleation kinetics of ammonium metavanadate precipitated by ammonium chloride

Cited by 35 publications

References 50 publications

Efficient Microwave Irradiation‐Assisted Hydrothermal Synthesis of Ammonium Vanadate Flake

Efficient Microwave Irradiation‐Assisted Hydrothermal Synthesis of Ammonium Vanadate Flake

Controlled Hydrothermal Precipitation of Alunite and Natroalunite in High-Aluminum Vanadium-Bearing Aqueous System

On the critical energy required for homogeneous nucleation in bubble chambers employed in dark matter searches

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