Solvent Extraction Studies for Separation of Zn(II) and Mn(II) from Spent Batteries Leach Solutions

. FALCO, M.J. QUINA, L. M. GANDO-FERREIRA , H. THOMAS AND G. CURUTCHET

SEPARATION SCIENCE AND TECHNOLOGY

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2014 vol. 49 p. 398 - 409

0149-6395

This study aims to assess the possibility of using solvent extraction processes for separating Zn(II) and Mn(II) dissolved in aqueous solutions obtained by acid bioleaching of spent alkaline and Zn-C batteries. In this context, Cyanex 272 and DEHPA were tested as extractant agents, and the former was shown to have better performance. Hence, the effect of four factors (equilibrium pH, extractant concentration, A/O ratio and temperature) into three response variables (extraction efficiency of Zn, YZn; extraction efficiency of Mn, YMn; separation factor, β) were tested according to a full factorial design (24) with two replicated centre points. Our study revealed that YZn depends mainly on the extractant concentration, YMn on the equilibrium pH and β on the equilibrium pH, extractant concentration and A/O ratio as well as on second and third order interactions. One extraction step is sufficient to reach high extraction of zinc in synthetic solutions, but two stages were required for real leaching liquor. The extraction kinetics is fast (less than 15 min) for both metals, even when real liquor was tested. The organic solvent can beefficiently recovered using a stripping solution of H2SO4 1 M and thus the process can be considered environmentally sustainable.