**4. Conclusions**

The results reported by our group[28] and by the group of the Portalegre Polytechnical Institute - Portugal[29] demonstrate that it is possible to obtain galvanic coatings in a bath prepared from zinc and manganese recovered from exhausted zinc-carbon batteries. Additionally these showed that the production of a protective Zn-Mn layer over steel related to the substitution of the primary painting process on metallic parts produced in foundries is possible to be developed as practical application.

Specifically thought in the results obtained in the experiments described it could be observed that the presence of polyethylene glycol or methylamine as additives in the electrolytic bath during electrochemical deposition favors the obtainment of a compact and homogeneous deposit containing a mixture of Zn and a Zn-Mn alloy, with a manganese content in the range of 2% to 7% in weight and the electrodeposited coatings with higher Mn content improve the anticorrosiveness of mild steel in saline environments. The proposed method may represent an alternative use for zinc and manganese recovered from exhausted alkaline and zinc-carbon batteries and thus minimize the adverse environment impacts caused by these residues. Moreover lixiviation solutions resulting from the hydrometallurgical treatment of spent domestic batteries, mainly, Zn–MnO2 batteries can be valued directly as electrodeposition baths for zinc and zinc alloys.

The fact that the methodology developed for recycling batteries can now produce the separa‐ tion of the elements of which these batteries are made can open new avenues of application for these recovered materials. As an example it could be produced nanostructures of Zinc Oxide by electrodeposition over different kind of surfaces that could be used as quantum dots in photovoltaic devices. Also it could be produce magnetic films from the hydrometallurgical treatment of spent Zn–MnO2 batteries by the electrochemical deposition of ferrites with different contents of Zn and Mn in the structure. However these subjects are still possibilities, because no work involving these potentials could be found in the literature.
