Leaching kinetics of scheelite in hydrochloric acid solution containing hydrogen peroxide as complexing agent

He, Gaohong; Zhao, Zhongwei; Wang, Xiaobo; Li, Jiangtao; Chen, Xingyu; He, Lihua; Liu, Xuheng

doi:10.1016/j.hydromet.2014.02.006

Cited by 38 publications

(9 citation statements)

References 17 publications

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“…17 The Mampel equation is used for the explanation of leaching reactions. 18,19 Experimental data obtained from the leaching of ZnFe 2 O 4 fits very well to the pseudohomogeneous reaction model with the correlation coefficient of over 0.95. ) ,…”

Section: Leaching Kinetics Of Znfe 2 Omentioning

confidence: 68%

“…The Mampel (pseudohomogeneous reaction model) equation (Equation 10), which is a special form of the Avrami‐Erofeev equation ( n = 1), is used for the modeling of reactions in which random nucleation on a large number of small crystallites is mentioned 17 . The Mampel equation is used for the explanation of leaching reactions 18,19 . Experimental data obtained from the leaching of ZnFe 2 O 4 fits very well to the pseudohomogeneous reaction model with the correlation coefficient of over 0.95.…”

Section: Resultsmentioning

confidence: 86%

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Leaching kinetics of electric arc furnace dust in nitric acid solutions

Zorağa

İlhan

Kalpakli

2020

Int J of Chemical Kinetics

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Electric arc furnace dust contains mainly ZnO, ZnFe 2 O 4 , and iron oxides. In this study, chemical composition of ZnO, ZnFe 2 O 4 , and Fe 2 O 3 and leaching kinetics of ZnO, ZnFe 2 O 4 , and Fe 2 O 3 in HNO 3 solutions were investigated. It was seen that the dissolution of ZnO is very fast, therefore the leaching kinetics of ZnO cannot be determined. Kinetic parameters and model equations were derived for the leaching of ZnFe 2 O 4 and Fe 2 O 3. Leaching kinetics of ZnFe 2 O 4 was explained by the pseudohomogeneous reaction model. Activation energy and order of HNO 3 concentration were found to be as 37.5 kJ mol −1 and 0.37, respectively. The model equation was derived as X ZnFe 2 O 4 = 1 − exp[−62.83 0.37 0 exp(−37 522∕8.314) ]. It was determined that experimental data for the leaching kinetics of Fe 2 O 3 best fit with the shrinking core model (SCM). Activation energy and order of HNO 3 concentration were found to be as 51.5 kJ mol −1 and 0.67, respectively The model equation was derived using SCM as X Fe 2 O 3 = {1 − [1 − 1181.45 0.67 o exp(− 51 545∕8.314) ] 3 } .

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Section: Leaching Kinetics Of Znfe 2 Omentioning

confidence: 68%

Section: Resultsmentioning

confidence: 86%

Leaching kinetics of electric arc furnace dust in nitric acid solutions

Zorağa

İlhan

Kalpakli

2020

Int J of Chemical Kinetics

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“…A 0 values were calculated from the intercepts of lines given in Figure , Figure b, and Figure b as 3.13 × 10 5 , 3.10 × 10 5 , and 3.34 × 10 5 , respectively. The average of these three values is 3.19 × 10 5 , which is used in the kinetic equation . As a result, the kinetics equation for rare earth extraction by oxidative leaching in this study can be described as …”

Section: Resultsmentioning

confidence: 99%

Green Recovery of Rare Earths from Waste Cathode Ray Tube Phosphors: Oxidative Leaching and Kinetic Aspects

Yin

Tian

et al. 2016

ACS Sustainable Chem. Eng.

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In this work, we developed a green and efficient process for the recovery of rare earths from waste cathode ray tube phosphors. The mixture of hydrochloric acid and hydrogen peroxide was identified as the most suitable leaching agent due to the synergistic effect. The effects of various parameters on leaching process were explored, and the optimal conditions with stirring speed 600 rpm, temperature 313 K, 1 M of H2O2, 4 M of HCl, and leaching time of 90 min were determined. Furthermore, a possible reaction mechanism was proposed, and the kinetics for the leaching process was investigated in detail. The leaching process was found to follow a shirking-core model, with the chemical reaction as the rate-controlling step. The apparent activation energy of the reaction was calculated as 52.3 kJ/mol, and the reaction orders for H2O2 and HCl were established as 0.82 and 2.13, respectively. The kinetic equation was established. Moreover, the optimal leaching conditions were applied to the waste phosphors, and the oxalate precipitation process was employed, achieving the recovery rate of rare earths >99.5%. After calcining, a well crystallized (Y0.95Eu0.05)2O3 product with a purity of 99% was obtained with an average diameter of 5 μm.

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“…In the presence of phosphate or phosphoric acid as chelating agent, hydrochloric acid (Xuin et al, 1986;Gurmen et al, 1999;Kahruman and Yusufoglu, 2006;Liu and Xue, 2010) and nitric acid (Zhang et al, 2015) was used to decompose scheelite forming soluble phosphotungstic acid chelate compound (H3PW12O40). The chelating agent can also be hydrogen peroxide with formation of soluble peroxotungstic acid ([WO(O2)2(H2O)2]) (He et al, 2014). However, the discharge of highsalinity wastewater of CaCl2 or Ca(NO3)2 could not be eliminated in these methods .…”

Section: Introductionmentioning

confidence: 99%

Sustainable and efficient leaching of tungsten in ammoniacal ammonium carbonate solution from the sulfuric acid converted product of scheelite

Shen

Zhou

Peng

et al. 2018

Journal of Cleaner Production

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To directly obtain solution of (NH4)2WO4 instead of Na2WO4 is the key for developing a cleaner technology of ammonium paratungstate production. In this paper, ammoniacal ammon iu m carbonate solution was adopted for leaching tungsten from the converted product, a mixture of H2WO4 and CaSO4 obtained by treating scheelite with sulfuric acid. The research indicates that tungsten can be efficiently extracted in form of ammonium tungstate solution with WO3 leaching yield of > 99.5% under moderate leaching conditions. The WO3 leaching yield is influenced by the transformation of calciu m sulfate to calcium carbonate due to forming CaWO4 through the secondary reaction between CaSO4 and (NH4)2WO4, whereas an excess (NH4)2CO3 (≥ 0.64 mol/L) can suppress the secondary reaction by facilitating the transformation. Additionally, the consumed ammonium carbonate can be recovered by treating the leaching residue with ammonium sulfate solution at above 70 o C. This work presents a cleaner and sustainable technique for producing ammonium paratungstate, with circulating the leaching reagents and bypassing the conversion of Na2WO4 to (NH4)2WO4.

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Leaching kinetics of scheelite in hydrochloric acid solution containing hydrogen peroxide as complexing agent

Cited by 38 publications

References 17 publications

Leaching kinetics of electric arc furnace dust in nitric acid solutions

Leaching kinetics of electric arc furnace dust in nitric acid solutions

Green Recovery of Rare Earths from Waste Cathode Ray Tube Phosphors: Oxidative Leaching and Kinetic Aspects

Sustainable and efficient leaching of tungsten in ammoniacal ammonium carbonate solution from the sulfuric acid converted product of scheelite

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