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

Quimica nova

Afonso, Júlio Carlos¹  Ibiapina, Vinício Francisco² 

[1] Instituto de Engenharia Nuclear, Rio de Janeiro, Brasil;Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil

关键词: Zinc-MnO2 dry cells;    acid leaching;    zinc extraction;    neutral organophosphorus extractants;    manganese oxalate;    sodium salts.;   

DOI  :  10.21577/0100-4042.20170249

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

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.

【 授权许可】

CC BY