Scheelite conversion in sulfuric acid together with tungsten extraction by ammonium carbonate solution

Li, Xiaobin; Shen, Leiting; Zhou, Qiusheng; Peng, Zhihong; Liu, Guihua; Qi, Tiangui

doi:10.1016/j.hydromet.2017.05.005

Cited by 42 publications

(21 citation statements)

References 12 publications

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“…According to our previous research 15 , the H2SO4 concentration markedly influences the conversion of tungsten concentrate. As shown in Fig.…”

Section: Conversion Experimentsmentioning

confidence: 86%

“…The phase analyses were performed by a X-ray diffractometer (D8-Advance; Bruker) using a Cu-Kα with 0.0085° step size at a scan rate of 1°• min -1 . The phase fractions of the solid converted products (Y), only taking in account the tungsten-containing species, were calculated semi-quantitatively by the relative intensity ratio method with less than 5% error range; 18 the details for data processing were described in our previous work 15,19 . The conversion ratios (η) of CaWO4 and (Fe,Mn)WO4 to H2WO4…”

Section: Procedures and Measurementmentioning

confidence: 99%

“…Forward and Vizsolyi 14 proposed a process in which calcium-containing tungsten concentrates were treated with sulfuric acid to form insoluble tungstic acid, followed by the separation of insoluble H2WO4 and CaSO4• nH2O using dihydric or polyhydric aliphatic alcohol as the lixiviant. Li et al 15 systematically studied scheelite concentrate conversion in sulfuric acid, and examined the performance of separation of H2WO4 and CaSO4• nH2O in an aqueous ammonium carbonate solution at ambient temperature, indicating that the sulfuric acid decomposing-ammonium carbonate leaching is a promising method.…”

Section: Introductionmentioning

confidence: 99%

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Wolframite Conversion in Treating a Mixed Wolframite–Scheelite Concentrate by Sulfuric Acid

Shen

Zhou

et al. 2017

JOM

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Complete wolframite conversion in sulfuric acid is significant for expanding the applicability of the sulfuric acid method for producing ammonium paratungstate. In this paper, the conversion of wolframite in treating a mixed wolframite-scheelite concentrate by sulfuric acid was studied systematically. The results show that the conversion of wolframite in sulfuric acid is more difficult than that of scheelite, requiring rigorous reaction conditions. A solid H2WO4 layer forms on the surfaces of the wolframite particles and becomes denser with increasing H2SO4 concentration, thus hindering the conversion. Furthermore, the difficulty in wolframite conversion can be mainly attributed to the accumulation of Fe 2+ (and/or Mn 2+) in the H2SO4 solution, which can be solved by reducing Fe 2+ (and/or Mn 2+) concentration through oxidization and/or a two-stage process. Additionally, the solid converted product of the mixed wolframite-scheelite concentrate has an excellent leachability of tungsten in an aqueous ammonium carbonate solution at ambient temperature, with approximately 99% WO3 recovery. This work presents a route for manufacturing ammonium paratungstate by treating the mixed concentrate in sulfuric acid followed by leaching in ammonium carbonate solution.

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“…According to our previous research 15 , the H2SO4 concentration markedly influences the conversion of tungsten concentrate. As shown in Fig.…”

Section: Conversion Experimentsmentioning

confidence: 86%

Section: Procedures and Measurementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wolframite Conversion in Treating a Mixed Wolframite–Scheelite Concentrate by Sulfuric Acid

Shen

Zhou

et al. 2017

JOM

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“…When tungsten ore is decomposed in acid solutions, a solid H2WO4 product layer will form on the surfaces of unreacted tungsten mineral particles. It can be dissolved incorporating actions, such as controlling the acid concentration and adding an oxidizing agent [25,26,45]. Due to the absence of thermodynamic data, unfortunately, this paper does not carry out a detailed thermodynamic analysis on tungsten ore decomposition to H2[WO3(C2O4)H2O] and H3PW12O40.…”

Section: In Hcl Solutionsmentioning

confidence: 99%

“…Hydrochloric, nitric or sulfuric acid in the presence of phosphorus was found to decompose scheelite and form a water-soluble phosphotungstic acid chelate compound (12-tungstophosphoric heteropoly acid, H3PW12O40) [21][22][23][24]. In previous work, we systematically studied the conversion of scheelite and mixed scheelite-wolframite concentrate in sulfuric acid, and found that the tungsten concentrates can be completely converted in H2SO4 solutions by adding an oxidizing agent and controlling the H2WO4 formation in moderate acid concentrations [25,26].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics of Tungsten Ores Decomposition Process Options

Shen

Taskinen

2018

The Minerals, Metals &Amp; Materials Series

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The thermodynamics of tungsten ore decomposition in mineral acid and alkaline solutions were studied. The published thermodynamic data of tungsten minerals were collected and assessed. The Gibbs energies of CaWO4 (-1538.43 kJ/mol), FeWO4 (-1053.91 kJ/mol), MnWO4 (-1206.08 kJ/mol), H2WO4 (-1003.92 kJ/mol), and Na2WO4 (-1455.58 kJ/mol, aq) at 25 o C were adopted in the calculation using HSC software. The results show that CaWO4 is decomposed more readily in Na2CO3 solution than in NaOH, while FeWO4 and MnWO4 are more reactive in NaOH solutions. From a thermodynamic point of view, tungsten ore decomposes easily in acid solutions despite most ∆ increasing slightly with temperature. Oxidizing Fe 2+ to Fe 3+ in acidic solutions facilitates decomposition of FeWO4, and the reaction of CaWO4 in H2SO4 solution occurs more easily than in other mineral acids, due to the formation of sparsely soluble CaSO4. The results fit well with the experimental data and industrial experience previously reported in the literature.

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Low‐energy technology for producing anhydrite in the CaCO₃–H₂SO₄–H₂O system derived from industrial wastes

Kamarou

Korob

Hil

et al. 2021

J of Chemical Tech & Biotech

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BACKGROUND: A high-quality anhydrite binder could be produced due to the exergy of sulfuric acid in the CaCO 3 -H 2 SO 4 -H 2 O system derived from industrial wastes. Waste of sulfuric acid derived from the production of heat-resistant fibers and wastes of limestone that was formed on the metallurgical enterprise were used for the synthesis of anhydrite. Such a product is safe from an environmental point of view and has many advantages, both operational and economic, over standard gypsum binders.RESULTS: The optimal technological parameters have been established and a technological scheme for producing anhydrite excluding the stage of calcium sulfate dihydrate formation has been proposed. Anhydrite production in the CaCO 3 -H 2 SO 4 -H 2 O system, due to the exergy of sulfuric acid, is a promising technology to replace the traditional thermal technology for producing anhydrite. This technology can reduce fuel costs because the required synthesis temperature is 95-105°С, instead of 800-1000°С in the traditional one, and this significantly reduces the cost of manufactured products. CONCLUSION:The maximum yield of synthetic anhydrite was provided by a limestone suspension taken in a stoichiometric amount. This neutralizing agent makes it possible to obtain particles of a prismatic shape, the size of which is generally more than 20 ∼m.

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Scheelite conversion in sulfuric acid together with tungsten extraction by ammonium carbonate solution

Cited by 42 publications

References 12 publications

Wolframite Conversion in Treating a Mixed Wolframite–Scheelite Concentrate by Sulfuric Acid

Wolframite Conversion in Treating a Mixed Wolframite–Scheelite Concentrate by Sulfuric Acid

Thermodynamics of Tungsten Ores Decomposition Process Options

Low‐energy technology for producing anhydrite in the CaCO₃–H₂SO₄–H₂O system derived from industrial wastes

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Scheelite conversion in sulfuric acid together with tungsten extraction by ammonium carbonate solution

Cited by 42 publications

References 12 publications

Wolframite Conversion in Treating a Mixed Wolframite–Scheelite Concentrate by Sulfuric Acid

Wolframite Conversion in Treating a Mixed Wolframite–Scheelite Concentrate by Sulfuric Acid

Thermodynamics of Tungsten Ores Decomposition Process Options

Low‐energy technology for producing anhydrite in the CaCO3–H2SO4–H2O system derived from industrial wastes

Contact Info

Product

Resources

About

Low‐energy technology for producing anhydrite in the CaCO₃–H₂SO₄–H₂O system derived from industrial wastes