Preparation and characterization of manganese and zinc oxides recovered from spent alkaline and Zn/C batteries using bio generated sulfuric acid as leaching agent

GALLEGOS M. VICTORIA; M. PELUSO; JORGE E. SAMBETH

JOM (1989)

SPRINGER

Año: 2018

1047-4838

Manganese, zinc and mixed manganese-zinc oxides were synthesized after abiohydrometallurgical process to recycle alkaline and Zn/C batteries. A mixture ofalkaline and Zn/C batteries was leached with biogenerated sulfuric acid. The effect ofpulp density, time, and use of additives, namely, H2O2 and Na2SO3, was studied.Using a S/L = 0.04 g mL-1, 2 h, 5 vol% H2O2 or 1 wt% Na2SO3 at 30 ºC and in onestep, 99% Zn and 90%-98% Mn were extracted. After leaching, manganese (MnOx)and zinc oxides (ZnO) were obtained by sequential precipitation first with KMnO4 andthen with Na2CO3, recovering 90 % Mn and 95 % Zn. Additionally, a mixedmanganese-zinc oxide was obtained by precipitation with NaOH until pH = 8 (ZM)recovering 28% Mn and 95% Zn. The Mn/Zn ratio was higher for the MnOx catalysts.Characterization by X-ray diffraction (XRD) and transmission electron microscopy(TEM) revealed the presence of a-MnO2 in MnOx with globular shape, wurtzite in ZnOoxide with spherical shape, and a mixture of ZnO wurtzite and ZnMn2O4 in ZM samplewith platelet-type shapes.