SEPARATION OF ZINC FROM MANGANESE BY SOLVENT EXTRACTION FROM ACIDIC LEACHATES OF SPENT ZINC-MnO2 DRY CELLS USING NEUTRAL ORGANOPHOSPHORUS EXTRACTANTS

This paper describes a route for recovering manganese and zinc from spent zinc-MnO2 dry cells via acid leaching using sulfuric or hydrochloric acids as leachants. Hydrogen peroxide was added as reductant. Experiments were run at 25-40 °C for 1-3 h. Under the best optimal conditions, over 97.5 wt.% of zinc and manganese were leached by both acids. Zn(II) was best extracted at high free acidity (≥ 1 mol L-1) with tributylphosphate (TBP) or trialkylphosphine oxides (Cyanex 923) diluted in n-heptane. Cyanex 923 was a better extractant than TBP, and the extraction was better performed in hydrochloric leachates. Mn(II) was more co-extracted from hydrochloric leachates and when Cyanex 923 was the extractant, but was easily scrubbed with dilute leachant (~1-2 mol L-1). Zn(II) striping was possible using 5 mol L-1 HCl or H2SO4. Manganese was precipitated as oxalate (MnC2O4.2H2O), free of leached contaminants. High-purity sodium salts of the anions of the leachants were recovered after slow evaporation of the final solution.

Bibliographic Details

Main Authors:	Ibiapina,Vinício Francisco, Afonso,Júlio Carlos, Silva,Rubens Souza da, Vianna,Cláudio Augusto, Mantovano,José Luiz
Format:	Digital revista
Language:	English
Published:	Sociedade Brasileira de Química 2018
Online Access:	http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422018000700770
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