Study on Mg2+ removal from ammonium dihydrogen phosphate solution by solvent extraction with di-2-ethylhexyl phosphoric acid

JianHong Luo; Jun Li; Kun Zhou; Yang Jin

Korean Journal of Chemical Engineering, Vol.28, No.4, 1105-1109, April, 2011

DOI10.1007/s11814-010-0468-0 Export Citation

Study on Mg2+ removal from ammonium dihydrogen phosphate solution by solvent extraction with di-2-ethylhexyl phosphoric acid

JianHong Luo, Jun Li^†, Kun Zhou, and Yang Jin

Department of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, P. R. China

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The extraction of Mg2+ from ammonium dihydrogen phosphate (MAP) solution by extractant (D2EHPA) and its mixture, including acidic extractant (HEHPEHE), alkaline extractant (TOA) and neutral extractant (TBP) respectively, is investigated. The good extraction selectivity of Mg2+ with D2EHPA from ammonium dihydrogen phosphate solution is verified, which is found to be associated with the cation exchange and chelation capability of D2EHPA on the basis of its molecular structure. The related thermodynamic data are also obtained in terms of experimental results as follows: the extraction enthalpy is 2.659×10^(-2) (J·mol^(-l)ㆍK^(-1)), the free energy is 1.501×103 (J·mol^(-1)) and the entropy is 4.441 (J·mol^(-1)). Meanwhile, the major influencing factors, such as the initial pH, the initial concentration of extractant, phase ratio and the extraction temperature on the extraction ratios of Mg2+, are studied, and the optimal process conditions are obtained. As shown in the extraction experiments for practical MAP solution, superior grade MAP can be obtained by three levels of extraction under optimal condition.

Keywords:Extraction Process;Di(2-ethylhexyl)phosphoric Acid;MAP

[References]

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Hoh YC, Chuang WS, Lee BD, Chang CC, Hydrometallurgy., 12, 375 (1984)
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[1] Ritcey GM and Ashbrook AW, Solvent Extraction: Principles and Applications to Process Metallurgy Vol. 1 Elsevier, 106 (1984)

[2] Hoh YC, Chuang WS, Lee BD, Chang CC, Hydrometallurgy., 12, 375 (1984)

[3] Soc. Chem. Ind., Cook LF and Szmokaluk WW, Refining of cobalt and nickel sulfate solution by solvent extraction using di-(2-ethyl hexyl.)phosphoric acid, Proceedings ISEC’ 71, London, 1, 451 (1971)

[4] Ritcey GM, Process options using solvent extraction for the processing of laterites, in: Nickel ’96, Kalgorlie, September, 251 (1996)

[5] Clark PDA, Cole PM, Fox MH, Purification of nickel sulphate using di-(2-ethyl hexyl) phosphoric acid, in: Lonsdail DH, Slater MJ Eds., ISEC’93, Solvent Extraction in the Process Industry, London, 175 (1993)

[6] Yao BH, Yukio N, Masatada S, Akihiko N, Kiyoshi H, Solvent Extr. Ion Exch., Solvent extraction of metal ions and separation of nickel_II. from other metal ions by organophosphorus acids, 14(5), 849 (1996)

[7] Feather A, Sole KC, Dreisinger DB, Pilot-plant investigation of manganese removal and cobalt purification by solvent extraction, in: ISEC’ 99, Barcelona, Spain, 56 (1999)

[8] Choi DW, Kim YH, Korean J. Chem. Eng., 20(4), 768 (2003)

[9] Song N, Zhao X, Jia Q, Zhou W, Liao W, Korean J. Chem. Eng., 27(4), 1258 (2010)

[10] Hydrometallurgy., Van DD, Pinoy L, Courtijn E, Verpoort F, Influence of ace-tate ions and the role of the diluents on the extraction of copper (II), nickel (II), cobalt (II), magnesium(II) and iron (II, III) with different types of extractants, 78, 92 (2005)

[11] Out EO, Chiarizia R, Solvent Extr. Ion Exch., Thermodynamics of the extraction of metal ions by dialkyl-substituted diphosphonic acids. II. The U(VI) and Sr(II) case., 19(6), 1017 (2001)