Preparation and Characterization of Manganese and Zinc Oxides Recovered from Spent Alkaline and Zn/C Batteries Using Biogenerated Sulfuric Acid as Leaching Agent

• Published in: JOM (1989) 2018-10, Vol.70 (10), p.2351-2358
• Main Authors: Gallegos, María V., Peluso, Miguel A., Sambeth, Jorge E.
• Format: Article
• Language: English
• Subjects: Additives; Chemistry/Food Science; Earth Sciences; Efficiency; Engineering; Environment; Experiments; Graphite; Hazardous materials; Hydrogen peroxide; Leaching; Manganese dioxide; Physics; Potassium; Potassium permanganate; Recycling; Sodium carbonate; Sodium hydroxide; Sodium sulfite; Sulfuric acid; Technical Communication; Transmission electron microscopy; Wurtzite; X-ray diffraction; Zinc compounds; Zinc oxide; Zinc oxides
• ISSN: 1047-4838; 1543-1851
• DOI: 10.1007/s11837-018-3043-5

Manganese, zinc and mixed manganese-zinc oxides were synthesized after a biohydrometallurgical process to recycle alkaline and Zn/C batteries. A mixture of alkaline and Zn/C batteries was leached with biogenerated sulfuric acid. The effect of pulp density, time and use of additives, namely, H 2 O 2 and Na 2 SO 3 , was studied. Using an S / L  = 0.04 g ml −1 , 2 h, 5 vol.% H 2 O 2 or 1 wt.% Na 2 SO 3 at 30°C and in one step, 99% Zn and 90–98% Mn were extracted. After leaching, manganese (MnO x ) and zinc oxides (ZnO) were obtained by sequential precipitation first with KMnO 4 and then with Na 2 CO 3 , recovering 90% Mn and 95% Zn. Additionally, a mixed manganese-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 MnO x catalysts. Characterization by x-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the presence of α-MnO 2 in MnO x with globular shape, wurtzite in ZnO oxide with spherical shape and a mixture of ZnO wurtzite and ZnMn 2 O 4 in the ZM sample with platelet-type shapes.