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Seongnam, South Korea

Batchu N.K.,Mokpo National University | Sonu C.H.,LS Nikko Copper Inc. | Lee M.S.,Mokpo National University
Hydrometallurgy | Year: 2014

Studies on solvent extraction equilibrium of Mn(II) from sulfuric acid solutions with a mixture of Cyanex 301 and TBP have been carried out. The extraction of Mn(II) by Cyanex 301 was enhanced significantly by the addition of TBP at a Cyanex 301 mole fraction of 0.6 and the synergistic coefficient calculated was 1.16. Synergistic extraction reaction was identified on the basis of slope analysis and extracted species was proposed to be MnA2 · TBP. The solvent extraction equilibrium constant was estimated from the extraction data by considering the formation of complexes and activity coefficients of metal species in the aqueous phase. There was a good agreement between calculated distribution ratios of Mn(II) and experimentally measured values. © 2014 Elsevier B.V. Source


Batchu N.K.,Mokpo National University | Sonu C.H.,LS Nikko Copper Inc. | Lee M.S.,Mokpo National University
Hydrometallurgy | Year: 2013

The solvent extraction of manganese(II) has been studied from chloride solutions using a mixture of Cyanex 272 and Cyanex 301 dissolved in kerosene. The mixture has shown a significant synergistic effect at XCyanex 272 = 0.6. The synergistic enhancement factor was calculated to be 14. The extracted species in the organic phase was found to be MnH2A 2B2 using slope analysis method. Stripping experiments showed that manganese could be recovered using dilute sulphuric acid solutions from the loaded mixture. The mixture has a potential for the separation of Mn(II) from other associated metals. © 2013 Elsevier B.V. Source


Kumar B.N.,Mokpo National University | Sonu C.H.,LS Nikko Copper Inc. | Lee M.S.,Mokpo National University
Journal of Chemical and Engineering Data | Year: 2013

Synergistic solvent extraction of manganese(II) using a mixture of Cyanex 272 and Cyanex 301 from chloride solutions has been studied in the view of developing a chemical model. Slope analysis method was used for the determination of extraction stoichiometry. The equilibrium constant for the synergistic solvent extraction reaction was calculated by taking into account of the complex formation reactions between Mn(II) and chloride ions. The activity coefficients of species in the aqueous phase were estimated by applying the Bromley equation. The calculated distribution ratios of Mn(II) agreed well with the experimentally measured values. © 2013 American Chemical Society. Source


Park S.-I.,LS Nikko Copper Inc. | Kwak I.S.,Engineering R and nter | Won S.W.,Chonbuk National University | Yun Y.-S.,Chonbuk National University
Journal of Hazardous Materials | Year: 2013

Glutaraldehyde (GA)-crosslinked chitosan beads (GA-CS) are prepared with coagulating solution containing sodium tripolyphosphate and GA, and used for the adsorption of metals from binary-metal solution Au(III) and Pd(II). GA-CS exhibited selective sorption of Au(III) in the Au(III)-Pd(II) mixture. X-ray diffraction analyses showed that Au(III) was reduced to Au(0) following sorption, while Pd(II) was present as unreduced divalent form. Increased GA led to more selectivity toward Au(III), indicating that Au(III) selectivity is attributed to reduction-couple sorption of Au(III) with a reducing agent GA. Furthermore, a 2-step desorption process enabled selective recovery of Pd and Au using 5. M HCl and 0.5. M thiourea-1. M HCl, respectively, leading to pure Pd(II) and Au(III)-enriched solutions. This finding may open a new way to design reduction-coupled selectivity-tunable metal sorbents by combination of redox potentials of metal ions and reducing agents. © 2013 Elsevier B.V. Source


Nguyen T.H.,Mokpo National University | Sonu C.H.,LS Nikko Copper Inc. | Lee M.S.,Mokpo National University
Journal of Industrial and Engineering Chemistry | Year: 2016

The separation of Ir(IV) and Rh(III) from chloride solution by extraction with amines (TOA, TEHA, Alamine 308, and Aliquat 336) was investigated. Ir(IV) was selectively extracted over Rh(III) by these extractants. HCl concentration affected little the extraction of metals. The highest separation factor of 82.5 between the two metals was obtained from 1 M HCl solution by extraction with Aliquat 336. Solution aging until 2 weeks depressed the extraction of Rh(III). The mixture of HCl and thiourea stripped Ir(IV) selectively from the loaded amines and thus promoted the separation. © 2016 The Korean Society of Industrial and Engineering Chemistry. Source

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