Green leaching of tungsten from synthetic scheelite with sulfuric acid-hydrogen peroxide solution to prepare tungstic acid

Zhang, Wenjuan; Chen, Yongqiang; Che, Jianyong; Wang, Chengyan; Ma, Baozhong

doi:10.1016/j.seppur.2020.116752

Cited by 25 publications

(4 citation statements)

References 25 publications

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“…The activation energy, E a , for the leaching reaction estimated from the slope of Fig. 9 gave 22.94 kJ/mol (< 40 kJ/mol), supporting the diffusion-controlled reaction mechanism as the rate-determining step for the dissolution reaction, consistent with the following stoichiometry [29][30][31]:…”

Section: Dissolution Kinetic Modelsupporting

confidence: 64%

Low-Energy Feasibility for Leaching an Indigenous Scheelite Ore for Industrial Applications

Baba

Kayode

Raji

2020

J. Sustain. Metall.

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In recent times, the increasing demand for pure tungsten and its compounds in defense, medicine, high technology, and emerging innovations due to its excellent properties such as its tensile strength, corrosion resistance, and high modulus of elasticity cannot be overemphasized. In this study, an acid leaching route was adopted for the extraction of pure tungsten from a Nigerian scheelite ore consisting primarily of scheelite (Ca 4.00 W 4.00 O 16.00 : 96-900-9627) and quartz (Si 6.00 O 6.00 : 96-900-5019). At optimal leaching conditions (2.5 mol/L HCl, 70 °C, < 75 µm), 88.5% of the initial 10 g/L ore reacted within 120 min. The low apparent activation energy (E a ) estimated as 22.94 kJ/mol with the reaction order of 0.96 affirmed the dissolution reaction to occur through the diffusion control mechanism of the first-order relation. The low E a obtained further supports the feasibility and eco-friendly dissolution process as ⁓11.5% of the undissolved materials analyzed to contain silica (SiO 2 : 96-900-5302) could be used as raw materials for some defined industrial applications.

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Section: Dissolution Kinetic Modelsupporting

confidence: 64%

Low-Energy Feasibility for Leaching an Indigenous Scheelite Ore for Industrial Applications

Baba

Kayode

Raji

2020

J. Sustain. Metall.

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“…The chemical precipitation methods can be also subdivided into CaCl 2 precipitation, acid precipitation and ammonia dissolution-evaporation crystallization methods. [19][20][21][22] Among them, acid precipitation method has the highest tungsten precipitation efficiency and simple operation, but the precipitation product is usually entrained with some impurities and needs further handling, while the ammonia dissolution-evaporation crystallization method can further remove some impurities in tungsten precipitation. Therefore, in order to recover the higher tungsten product, this paper used the acid method to precipitate tungsten to obtain crude tungstic acid in a solution containing tungsten, followed by ammonia water dissolution and evaporating crystallization to obtain ammonium paratungstate (APT).…”

Section: Introductionmentioning

confidence: 99%

“…Compared with the above methods of recovering tungsten, the chemical precipitation method has a lower cost and operational requirements, and displays a superior recovery effect by optimizing the reaction conditions; it is widely used in the recovery of metals from spent catalyst. The chemical precipitation methods can be also subdivided into CaCl 2 precipitation, acid precipitation and ammonia dissolution–evaporation crystallization methods 19‐22 . Among them, acid precipitation method has the highest tungsten precipitation efficiency and simple operation, but the precipitation product is usually entrained with some impurities and needs further handling, while the ammonia dissolution–evaporation crystallization method can further remove some impurities in tungsten precipitation.…”

Section: Introductionmentioning

confidence: 99%

Recovery of tungsten from spent selective catalytic reduction catalyst by sulfuric acid precipitation and evaporation crystallization method

Wang,

Yang,

Chen

et al. 2023

J of Chemical Tech & Biotech

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BackgroundSelective catalytic reduction (SCR) can effectively handle NOx from the flue gas in the coal‐fired power plant. However, as the core part of SCR method, V2O5‐WO3/TiO2 catalyst has a limited operation life in the complex flue gas environment. To recover rare metals from spent catalyst can not only bring economic benefits, but also solve the environmental problems. The process of reducing acid leaching and further roasting‐water leaching can realize the efficient recycling of V, W and Ti.ResultsAfter reducing acid leaching and roasting‐water leaching to treat spent SCR catalyst, the obtained solution containing tungsten was used as the raw material in this study. The optimal pH value of solution to remove Si and Al impurities was 9.2‐9.5. The best tungsten precipitation conditions were shown as follows: tungsten concentration of 30 g/L, sulfuric acid concentration of 8 mol/L, reaction temperature of 70°C and reaction time of 2 h. Under the optimal tungsten precipitation conditions, the tungsten precipitation efficiency can reach 92.53%. Finally, in order to further improve the purity of the crude H2WO4, the crude H2WO4 was fully dissolved into ammonia, followed by filtration and evaporation crystallization to obtain the 5(NH4)2O·12WO3·5H2O (APT) crystals with the purity of 93.05wt%. The crystallization efficiency of APT was 73.37% at 60°C for 2 h with the rotor speed of 400 r/min.ConclusionThese results indicated that the higher purity of APT crystals can be obtained by the steps of removing Si and Al, precipitation tungsten by sulfuric acid, ammonia dissolution and evaporation crystallization.This article is protected by copyright. All rights reserved.

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“…Scheelite is the main raw material of tungsten industry, which is usually associated with a certain amount of calcium fluoride ( Dong et al, 2021 ; Wang et al, 2021 ; Liu et al, 2022 ; Zhang et al, 2022 ) At present, scheelite is almost treated by the process of “sodium hydroxide decomposition-anion exchange” to produce ammonium paratungstate (APT) ( Zhao et al, 2013 ; Xue et al, 2019 ; Yin et al, 2020 ; Zhang et al, 2020 ). In the leaching process, scheelite was decomposed by sodium hydroxide to generate sodium tungstate solution, meanwhile calcium fluoride was also decomposed and entered the sodium tungstate solution as the form of sodium fluoride ( Li et al, 2022 ; Yang et al, 2023 ).…”

Section: Introductionmentioning

confidence: 99%

Fluorine removal from sodium tungstate ion exchange effluent by precipitation with addition of lanthanum chloride

Wan,

Zhao,

Cao

et al. 2023

Front. Chem.

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The waste water generated from the sodium tungstate ion exchange process of scheelite hydrometallurgical extraction contains a certain concentration of fluorine ion, which caused environmental pollution and harmed human health. In this study, a new method for removing fluorine from the wastewater by precipitation with addition of lanthanum chloride was proposed. In the process, fluorine was removed by from the solution as insoluble lanthanum fluoride precipitates. To explore the favourable conditions for the formation of lanthanum fluoride, thermodynamic analysis of the La-F-H2O system was conducted. Results show that lanthanum fluoride is stable when the solution pH value is between 1.0 and 10.0, and the lanthanum fluoride is gradually converted into lanthana hydroxide when the pH value is more than 10.0 at 298K. The effects of various parameters on the fluorine removal were studied, and the optimum process parameters were determined. More than 92% of the fluorine can be removed when the concentration of fluorine in the solution ranged from 60 to 400 mg/L, the dosage of lanthanum chloride was 1.3 times of the theoretical amount, the pH value was 8.0 at 60°C for 30 min. After removing fluorine from the solution, the resiual fluorine concentrtion was lower than 10 mg/L, which could meet the requirement of national wastewater discharge.

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Green leaching of tungsten from synthetic scheelite with sulfuric acid-hydrogen peroxide solution to prepare tungstic acid

Cited by 25 publications

References 25 publications

Low-Energy Feasibility for Leaching an Indigenous Scheelite Ore for Industrial Applications

Low-Energy Feasibility for Leaching an Indigenous Scheelite Ore for Industrial Applications

Recovery of tungsten from spent selective catalytic reduction catalyst by sulfuric acid precipitation and evaporation crystallization method

Fluorine removal from sodium tungstate ion exchange effluent by precipitation with addition of lanthanum chloride

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