A mechanism of calcium fluoride-enhanced vanadium leaching from stone coal

Wang, Fei; Zhang, Yimin; Liu, Tao; Huang, Jing; Zhao, Jie; Zhang, Guobin; Liu, Juan

doi:10.1016/j.minpro.2015.06.013

Cited by 53 publications

(16 citation statements)

References 23 publications

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“…Finally, [AlF 5 ] 2À is generated by the further coordination of F À (M 14 ). This nal state of Al 3+ is consistent with the actual test result of Wang et al 23 In phlogopite, the center Mg atom is also pulled out of the octahedron by the addition of F À (P 9 / P 13 ). But the center Mg atom completely get away from the octahedral surface until the eighth F À added (P 14 ).…”

Section: Essential Difference Of Mica Dissolutionsupporting

confidence: 90%

Vanadium occupation and its leachability differences in trioctahedral and dioctahedral mica

et al. 2019

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Section: Essential Difference Of Mica Dissolutionsupporting

confidence: 90%

Vanadium occupation and its leachability differences in trioctahedral and dioctahedral mica

et al. 2019

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“…At the end of each leaching test, the leaching slurry was filtered by vacuum filtration and the leaching solution and leaching residue were obtained. The amount of vanadium pentoxide in the leaching solution was determined by ferrous ammonium sulfate titration method [22].…”

Section: Procedures and Methodsmentioning

confidence: 99%

Mechanism of Enhancing Extraction of Vanadium from Stone Coal by Roasting with MgO

et al. 2017

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Abstract:In this paper, the extraction of vanadium from stone coal by roasting with MgO and leaching with sulfuric acid has been investigated, and the mechanism analysis of stone coal roasting with MgO was studied. The results indicated that under the conditions that the mass fraction of the particles with grain size of 0-0.074 mm in raw ore was 75%, the roasting temperature was 500 • C, the roasting time was 1 h, MgO addition was 3 wt %, the sulfuric acid concentration was 20 vol %, the liquid-to-solid ratio was 1.5 mL/g, the leaching temperature was 95 • C, and leaching time was 2 h, resulting in a vanadium leaching efficiency of 86.63%, which increased by 7.73% compared with that of blank roasting. The mechanism analysis showed that the degree of calcite decomposition was low and, thus, magnesium vanadate was more easily formed than calcium vanadate below 500 • C. Moreover, magnesium vanadate was easier to dissolve than calcium vanadate during the sulfuric acid leaching process. Thus, the vanadium leaching efficiency was enhanced by using MgO as a roasting additive below 500 • C. Additionally, at high temperature the formation of tremolite would consume calcium oxide produced from the decomposition of calcite, thus, the formation of calcium vanadate was hindered, and V 2 O 5 would react with MgO to form magnesium vanadate. Therefore, the vanadium leaching efficiency of roasting with MgO was higher than that of blank roasting at high temperature.

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“…The recovery of vanadium depends strongly on roasting parameters, such as CaO/V 2 O 5 ratio, calcination temperature, heating rate, and roasting time, as well as leaching conditions, such as particle size, solid/liquid ratio, leaching temperature, acid concentration, and stirring rate. It was reported that the recovery of vanadium also can be improved by using methods such as microwave roasting, mechanical activation pretreatment, multistage leaching, electro‐oxidation leaching, liquid oxidation technology, and leaching with additives (CaF 2 , HF, NaClO) …”

Section: Introductionmentioning

confidence: 99%

Dissolution kinetics of calcium vanadates in sulfuric acid: a fundamental study for the vanadium extraction process

Huang

Xiang

Wang

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND: The dissolution behavior of calcium vanadates is vital for the vanadium extraction process, as well as the utilization of calcium vanadates based function materials. Therefore, the dissolution kinetics study of calcium vanadates (CaV 2 O 6 , Ca 2 V 2 O 7 , and Ca 3 V 2 O 8 ) in sulfuric acid are presented. The effects of stirring speed, solid/liquid ratio, pH, and temperature on the dissolution rate of calcium vanadates were determined. The mineralogical and microstructure of the residue after dissolution are also performed. RESULTS:The results showed that the dissolution rate of calcium vanadates significantly increased with the increase of temperature from 30 to 70°C. Under the conditions with solid/liquid ratio of 1:150 g mL −1 , temperature range of 30 to 70°C, and pH of 4, the rate of Ca 3 V 2 O 8 dissolution is the fastest, followed by Ca 2 V 2 O 7 and CaV 2 O 6 , especially at low temperature. CONCLUSION: The mineralogical analyses results showed that the main products for the dissolution of Ca 2 V 2 O 7 and Ca 3 V 2 O 8 are needle-like CaSO 4 ·0.5H 2 O, whereas for CaV 2 O 6 are undissolved CaV 2 O 6 and hydrolyzed V 2 O 5 . The dissolution kinetics indicate that the dissolution of CaV 2 O 6 follows second-order pseudo-homogeneous model, whilst Ca 2 V 2 O 7 and Ca 3 V 2 O 8 follow the diffusion through the product or ash layer model. The apparent activation energies for the dissolution of CaV 2 O 6 , Ca 2 V 2 O 7 , and Ca 3 V 2 O 8 were determined as 46.44, 38.72, and 23.50 kJ mol −1 , respectively.

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A mechanism of calcium fluoride-enhanced vanadium leaching from stone coal

Cited by 53 publications

References 23 publications

Vanadium occupation and its leachability differences in trioctahedral and dioctahedral mica

Vanadium occupation and its leachability differences in trioctahedral and dioctahedral mica

Mechanism of Enhancing Extraction of Vanadium from Stone Coal by Roasting with MgO

Dissolution kinetics of calcium vanadates in sulfuric acid: a fundamental study for the vanadium extraction process

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