Caracterización de los compuestos químicos obtenidos al emplear ácido acético como agente lixiviante en el tratamiento hidrometalúrgico de pilas Ni-MH desechadas.

Introduction. Nickel-Metal Hydride (Ni-MH) batteries usually end up in municipal landfills after their useful life, which may release Ni, a potential toxic element, and rare earth elements which can react with water and release hydrogen. Objective. Recover the metals (Ni, Co y La) contained in the electrode material of spent Ni-MH batteries, as organic salts, using vinegar as a leaching agent in a hydrometallurgical treatment. Materials and methods. Electrodes from a sample of spent Ni-MH batteries were leached separately with a 5% v/v acetic acid solution (commercial vinegar). The pregnant liquor was subjected to an evaporation/crystallization process at 70°C for 24 h. The products were characterized by the following techniques: atomic spectroscopy (AS), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Results. It is possible to recover 40% of the Ni from anodic material and about 45% of Ni from the cathodic material. Nickel, cobalt and lanthanum acetates were detected in the anodic product; and nickel, cobalt and potassium acetates were detected in the cathodic product. Conclusion. Because these salts are typically used in the ceramics, textile and agricultural industries, the proposed hydrometallurgical treatment could be used for the valorization of the electrode material from spent Ni-MH batteries. [ABSTRACT FROM AUTHOR]