ABSTRACT
High purity electrolytic manganese dioxide (EMD) is the main raw material used for manufacturing of zinc and manganese based portable batteries (alkaline with manganese AlMn and zinc carbon Zn-C). Lately, due to the progressive depletion of MnO(2) natural resources, the quantity of artificially electrolytic produced MnO(2) has started to increase to satisfy the demand. This paper describes an electrolytic process for the simultaneous production of the following components:The electrolysis process was conducted in a specialized laboratory facility. The study was particularly focused on the following electrolysis process parameters:
Subject(s)
Electric Power Supplies , Manganese Compounds/isolation & purification , Oxides/isolation & purification , Zinc/isolation & purification , Electrolysis , Manganese Compounds/chemistry , Oxidation-Reduction , Oxides/chemistry , Refuse Disposal/methods , Sulfates/chemistry , Sulfuric Acids/chemistry , X-Ray Diffraction , Zinc/chemistryABSTRACT
Used batteries contain numerous metals in high concentrations and if not disposed of with proper care, they can negatively affect our environment. These metals represent 83% of all spent batteries and therefore it is important to recover metals such as Zn and Mn, and reuse them for the production of new batteries. The recovery of Zn and Mn from used batteries, in particular from Zn-C and alkaline ones has been researched using hydrometallurgical methods. After comminution and classification of elemental components, the electrode paste resulting from these processes was treated by chemical leaching. Prior to the leaching process the electrode paste has been subjected to two washing steps, in order to remove the potassium, which is an inconvenient element in this type of processes. To simultaneously extract Zn and Mn from this paste, the leaching method in alkaline medium (NaOH solution) and acid medium (sulphuric acid solution) was used. Also, to determine the efficiency of extraction of Zn and Mn from used batteries, the following variables were studied: reagents concentration, S/L ratio, temperature, time. The best results for extraction yield of Zn and Mn were obtained under acid leaching conditions (2M H2SO4, 1h, 80°C).
