Solvent Extraction Research and Development, Japan
Online ISSN : 2188-4765
Print ISSN : 1341-7215
ISSN-L : 1341-7215
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Displaying 1-6 of 6 articles from this issue
Original Articles
  • Xiaohua JING, Zhumei SUN, Dandan ZHAO, Donghui PAN, Yage ZHANG, Yu ZHA ...
    2022 Volume 29 Issue 2 Pages 39-48
    Published: 2022
    Released on J-STAGE: April 25, 2022
    JOURNAL FREE ACCESS

    In this research, the kinetics of Co(II) extraction from sulfate medium by the system of “[C8H17NH3][Cyanex 272]+diluent sulfonated kerosene” were investigated using the single drop falling technique. The time of drop formation and coalescence was determined for calculating the Co(II) transfer flux. The influences of aqueous pH, Co(II) concentration and [C8H17NH3][Cyanex 272] concentration on the revised Co(II)-transfer flux (F') were investigated with aim of obtaining reaction orders for extraction rate equations. With the conditions of Co(II) concentration of 0.24 mol/L, [C8H17NH3][Cyanex 272] concentration of 0.24 mol/L, extraction temperature of 298 ± 0.5 K and the normal atmospheric pressure, activation energies (Ea) of extraction reaction for the aqueous pH of 3.0, 4.0 and 5.0 are 3.45, 3.83 and 5.17 kJ/mol, respectively. The equations of extraction rate were calculated and listed in our research based on the different aqueous pH of 3.0, 4.0 and 5.0. The extraction reaction is a diffusion control process according to the values of Ea. The details studies on the kinetics of Co(II) extraction from simulated aqueous solution are significant to optimize its extraction processes.

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  • Kuifang ZHANG, Xiaocong ZHONG, Jinzhang TAO, Ruixiang WANG, Zhiqiang L ...
    2022 Volume 29 Issue 2 Pages 49-59
    Published: 2022
    Released on J-STAGE: April 25, 2022
    JOURNAL FREE ACCESS

    A novel approach for recovering yttrium from high ferric and strong acidic sulphate leach solutions of deep-sea mud by stepwise extraction and stripping has been developed. The results show that the first step extraction by N235+TBP system can extract H2SO4 well and adjust the raffinates to a desirable pH, while only the iron was selectively co-extracted with negligible loss of yttrium ions. The organic solution can be easily regenerated by using a 50 g/L H2SO4 solution to strip extracted iron followed by using deionized water to strip H2SO4. The raffinate could be directly used for the second step of yttrium extraction by P204+TBP system, while iron was co-extracted. The co-extracted yttrium and iron could be separated well through a sequentially stepwise stripping process using a 50 g/L H2SO4 solution and a 0.6 mol/L H2C2O4 solution. Over the whole process, yttrium was separated well from the sulphate leach solutions and enriched into the strip liquor of yttrium sulfate. The organic extractants could be returned for recycling.

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Notes
Technical Reports
  • Masatoshi TAKANO, Satoshi ASANO, Masahiro GOTO
    2022 Volume 29 Issue 2 Pages 79-84
    Published: 2022
    Released on J-STAGE: April 25, 2022
    JOURNAL FREE ACCESS

    In this study, we investigated an efficient recovery method of yttrium from a sulfuric acid leaching solution of spent Ni-MH battery electrode materials. In this newly proposed method, yttrium, one of the heavy rare earths (HREEs), was coprecipitated with light rare earths (LREEs) in the preliminary crude separation, and the residual yttrium was precisely recovered by solvent extraction using di-(2-ehylhexyl) phosphoric acid (D2EHPA) as the extractant. Yttrium in the leaching solution of 0.7 g/L that remained at 0.2 g/L after the coprecipitation operation; however, it could be reduced to 0.001 – 0.002 g/L by the solvent extraction process in the following step. In this technical report, we focused on the solvent extraction operation. The extractant, D2EHPA, has a high affinity for yttrium, and we confirmed the possibility of improving the recovery yield of yttrium from 43% by coprecipitation alone to 98% by introducing solvent extraction.

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