Leaching kinetics of synthetic CaWO4 in HCl solutions containing H3PO4 as chelating agent

Kahruman, Cem; Yusufoğlu, İbrahim

doi:10.1016/j.hydromet.2005.12.003

Cited by 40 publications

(12 citation statements)

References 3 publications

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“…[6], the units of T, P, and t are Kelvin, bar, and seconds, respectively. The differentiation of Eq.…”

Section: ½6mentioning

confidence: 99%

“…Kahruman and Yusufoglu [6] investigated the leaching kinetics of scheelite mineral in HCl solution containing H 3 PO 4 as a chelating agent, and Kahruman [7] studied the thermal decomposition mechanism of APTH in detail. 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.…”

Section: Introductionmentioning

confidence: 99%

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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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“…[6], the units of T, P, and t are Kelvin, bar, and seconds, respectively. The differentiation of Eq.…”

Section: ½6mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Investigation of the Oxidation Kinetics of Phosphotungsten Suboxide

Kalpakli

Yusufoğlu

2007

Metall Mater Trans B

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“…With an extension of the reaction time, the thickness of the product layer increases and, thus, hinders the reaction [12]. An alternative method that has been proposed to avoid the formation of insoluble H 2 WO 4 takes advantage of the complex effect between W and chelating agents, such as oxalic, tartaric, citric, or phosphoric acid [13][14][15]. However, the process suffers from severe corrosion and volatilization of hydrochloric acid and in consequence it is environmentally harmful.…”

Section: Introductionmentioning

confidence: 99%

Leaching kinetics of scheelite with nitric acid and phosphoric acid

Zhang

Zhao

2015

International Journal of Refractory Metals and Hard Materials

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“…Generally, tungsten minerals are digested with HCl, NaOH, or Na 2 CO 3 solutions (Jé ssica et al, 2012;Amer, 2000;Srinivas et al, 2000;Kahruman and Yusufoglu, 2006;Gurmen et al, 1999). In China, wolframite and scheelite are digested with NaOH solution in an autoclave, and the leaching solution (sodium tungstate) is subsequently treated with a strong basic anion-exchange resin (201×7).…”

Section: Introductionmentioning

confidence: 99%