Reciclagem de pilhas: recuperação do manganês na forma do dióxido de manganês eletrolítico. / Recycling of batteries: recovery of manganese in the form of electrolytic manganese dioxide.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Considering the growing demand for products containing manganese in its composition, this work seeks to verify the possibility of using depleted batteries as a source of manganese applying the electrolytic process. It was used an electrolyte solution containing the metal ions: Ca (270mg / L), Ni (3000 mg / L), Co (630 mg / L), Mn (115300 mg / L), Ti (400 mg / L) and Pb (20 mg / L) in concentrated sulfuric acid, following data from previous research. The production of electrolytic manganese dioxide (EMD) was performed through galvanization using a stabilized source that monitored the potential of the working electrode. It was preliminary used an electrode of lead and two counter electrodes of graphite at a temperature of 98ºC (± 2ºC) and current density of 1.69A.dm-2. After preliminary verifying the possibility of obtaining electrolytic manganese dioxide (EMD), the process was systematically repeated, applying different current density (0.61A.dm-2 to 2.51A.dm-2) and pH (0.00 to 1.20). The material obtained at these variations was analyzed through the process of X-ray fluorescence spectrometry, X-ray diffraction, specific surface area (BET) and scanning electron microscopy (SEM). The best values referring to current efficiency, level of purity and specific surface area were obtained with the current density ranging between 1.02 A.dm-2 and 1.39 A.dm-2, and pH 0.50. In any of the tested electrolysis conditions the -MnO2 structure was obtained as evidenced by the diffraction of X-rays analysis. The results indicate the feasibility of this recycling process as an alternative before shortage of natural sources of MnO2 and as a means of reducing environmental pollution caused by the disposal of batteries.

ASSUNTO(S)

manganese electroplating manganês recycling waste reciclagem de resíduos urbanos eletrodeposição

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