Acidic leaching of scheelite concentrate and production of hetero-poly-tungstate salt

Gürmen, Sebahattin; Timur, Servet; Arslan, Cüneyt; Duman, İsmail

doi:10.1016/s0304-386x(98)00080-2

Cited by 58 publications

(33 citation statements)

References 3 publications

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“…Similar findings indicating the capability of this species to accumulate Fe, Cu, Cd, Pb, and Bi were also determined. Together with a complexation agent such as phosphate, and depending on pH, these elements can produce water-soluble complexes that are transported to the upper parts of plants (Gürmen et al 1999). High soil phosphate levels in the polluted sites determined in an earlier study suggest the possible complexation with the phosphate anion (Güleryüz et al 2002).…”

Section: Resultsmentioning

confidence: 98%

Elemental composition of Marrubium astracanicum Jacq. growing in tungsten-contaminated sites

Guleryuz

Erdemir

Arslan

et al. 2016

Environ Sci Pollut Res

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This study evaluates the elemental (W, Mo, Zn, Fe, Cu, Cd, Mn, Pb, Cr, Co, B, and Bi) composition of Marrubium astracanicum Jacq. (Lamiaceae), around the abandoned tungsten mine on Uludağ Mountain, Turkey, to determine if it is an appropriate candidate for phytomonitoring and/or phytoremediation purposes. Three sample sites were selected around the mine for soil and plant sampling. Two sites approximately 500 m from the mine were assumed to be unpolluted sites. The other site was selected from a waste removal pool (WRP) and was assumed to be a polluted site. The soil and different organs (roots, leaves, and flowers) of plant samples were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to determine the elemental content. The classic open wet digestion procedure was applied to the samples with 5 mL HNO3 and 3 mL H2O2 in a borosilicate glass vessel for the roots, leaves, and the flowers of the plants. Kjeldahl digestion was used for the soil samples. The W, Zn, Fe, Cu, Cd, Mn, Pb, B, and Bi contents were found to be higher in the soil samples from the waste removal pools compared with the samples from the unpolluted sites. We also found that the elemental composition of M. astracanicum has generally been increased by the activity of the tungsten mine, and there were significant correlations between the elemental contents of the soil samples and plant parts, except for Mo and Cr. The high level of many elements in the soil samples indicates the presence of contamination related to tungsten-mining activity on Uludağ Mountain. Assessing the elemental contents of M. astracanicum, we can suggest this species as a candidate for phytoremediation purposes of W-contaminated sites due to its high W-accumulation capacity.

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Section: Resultsmentioning

confidence: 98%

Elemental composition of Marrubium astracanicum Jacq. growing in tungsten-contaminated sites

Guleryuz

Erdemir

Arslan

et al. 2016

Environ Sci Pollut Res

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“…For the characterization of intermediate and end products of the decomposition, thermogravimetric analysis (TGA), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), XRD, scanning electron microscopy, and evolved gas analysis (EGA) analytical methods were used. Kahruman [7] found that the evolution of NH 3 gas during decomposition in air began at higher temperatures in contrast to lower temperature suggested by Gurmen et al [5] It is important to note that the substance still contained P 2 O 5 . Kahruman [7] proposed the end products of decomposition of APTH in air and in inert gas atmosphere to be P 2 O 5 24WO 3 and P 2 O 5 W 24 O 70 , respectively.…”

Section: Introductionmentioning

confidence: 90%

“…Gurmen et al [5] proposed an alternative production method for tungsten powder production with particle size of less than 1 lm. In this proposed method, a scheelite mineral was dissolved in HCl solution containing phosphate ions as chelating agent.…”

Section: Introductionmentioning

confidence: 99%

The Investigation of the Oxidation Kinetics of Phosphotungsten Suboxide

Kalpakli

Yusufoğlu

2007

Metall Mater Trans B

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Dark blue colored phosphotungsten suboxide, which has the characteristics of phosphate tungsten oxide bronze, is formed during the thermal decomposition of ammonium phosphotungstate hydrate (APTH) in inert gas atmosphere. The aim of this study is to investigate the oxidation kinetics of phosphotungsten suboxide at isothermal conditions. Pellets prepared from phosphotungsten suboxide powder that were preheated at 1173 K temperature in inert gas atmosphere were used in the oxidation experiments. The sensitive measurement of weight increases was determined by the microelectronic microbalance. The oxidation reaction was carried out in the temperature range of 690 and 778 K and oxygen partial pressure range of 0.04 and 0.21 bar. The effects of gas flow rate, temperature, and oxygen partial pressure on the reaction rate were determined. The rate equation was derived by applying the ''Nucleation and Growth Kinetics'' model. The reaction rate was found to be of 0.94 order with respect to oxygen partial pressure, and the activation energy was 159 kJ mol )1 .

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“…Figure 2d shows the increasing effect of HCl on W levels, while the phosphoric acid concentration slightly increased the achieved contents of W. This increment was more significant after 10.5 M. As mentioned, HCl was selected as a parameter to increase the solubility for complex formation. 29 Thus, the tendency of the figure may be attributed to the collaboration of HCl and H 3 PO 4 for complexation. W levels slightly decreased until near 2 M and then increased with HCl versus temperature (Figure 2e).…”

Section: −mentioning

confidence: 99%

“…The selectivity of the phosphate anion may be assumed as important in this case. Elemental contents of the studied area were mentioned by Gürmen et al and Güleryuz et al 29,30 Additionally, a broad range of elements were quantified by using ICP-MS from the soil of A. cretica in our earlier studies, and W, Mo, Zn, Fe, Cu, Co, Bi, Mn, Cd, Cr, and As levels were determined to be in different ranges. Among the quantified elements, one of the important interfering ions may be molybdenum; its antagonist effect on complexation was observed (with violet color) for the soil extracts together with the determined high Mo levels from the uncontaminated soils of the same species in our earlier works.…”

Section: Analysis Of Response Surfacesmentioning

confidence: 99%

Development of a sample preparation strategy for the determination of tungsten in soil samples by inductively coupled plasma mass spectrometry using a response surface methodology

Erdemir¹

2017

Turk J Chem

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An alternative rapid digestion method has been developed for the determination of tungsten (W) in soil samples using fractionation studies and response surface methodology. The digestion method using the Kjeldahl instrument was applied to samples, and soluble tungsten was determined via inductively coupled plasma mass spectrometry. Digestion parameters were selected depending on the results of fractionation studies and optimized using a four-factor and five-level central composite design. The contributions of the phosphoric acid concentration (X 1) , digestion temperature (X 2) , digestion time (X 3) , and hydrochloric acid concentration (X 4) were evaluated for the determination of W from samples in which its levels were maximum. Optimum conditions for factors were found to be X 1 = 9.00 M, X 2 = 124 • C, X 3 = 45 min, and X 4 = 1.52 M using a predicted W level of 86.82 µ g L −1 . This yielded an expected level of 1736.40 mg kg −1 under the optimized conditions. Experimental W levels were in good agreement with this predicted level and found to be 1682.69 mg kg −1 . Thus, measured W levels showed the versatility of the central composite design in such a complex soil matrix for method development.

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Acidic leaching of scheelite concentrate and production of hetero-poly-tungstate salt

Cited by 58 publications

References 3 publications

Elemental composition of Marrubium astracanicum Jacq. growing in tungsten-contaminated sites

Elemental composition of Marrubium astracanicum Jacq. growing in tungsten-contaminated sites

The Investigation of the Oxidation Kinetics of Phosphotungsten Suboxide

Development of a sample preparation strategy for the determination of tungsten in soil samples by inductively coupled plasma mass spectrometry using a response surface methodology

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