M.B.J.G. Freitas

AVALIAÇÃO DA LIXIVIAÇÃO DO CÁDMIO E NÍQUEL PROVENIENTES DA DEGRADAÇÃO DE BATERIAS NÍQUEL-CÁDMIO EM UMA COLUNA DE SOLO

EVALUATION OF THE LEACHED CADMIUM AND NICKEL FROM THE DEGRADATION OF NICKEL–CADMIUM BATTERIES IN A COLUMN OF SOIL. Spent nickel–cadmium (Ni–Cd) batteries and salts of nickel and cadmium were placed in two different columns of soil for a period of two years. A leaching solution was passed through them at ambient temperature in this period. The behavior of metals in each column was then evaluated. Under the conditions of the experiment, cadmium and nickel demonstrated the potential to contaminate and affect the natural cycles of soil. The disposal of Ni–Cd batteries directly to the soil also increased the concentration of nickel (349 mg kg−1) and cadmium (2890 mg kg−1), sometimes exceeding the intervention values defined in CONAMA resolution 420/09.

Método hidrometalúrgico para reciclagem de metais terras raras, cobalto, níquel, ferro e manganês de eletrodos negativos de baterias exauridas de Ni-MH de telefone celular

A hydrometallurgical method for the recovery of rare earth metals, cobalt, nickel, iron, and manganese from the negative electrodes of spent Ni - MH mobile phone batteries was developed. The rare earth compounds were obtained by chemical precipitation at pH 1.5, with sodium cerium sulfate (NaCe(SO4)2.H2O) and lanthanum sulfate (La2(SO4)3.H2O) as the major recovered components. Iron was recovered as Fe(OH)3 and FeO. Manganese was obtained as Mn3O4.The recovered Ni(OH)2 and Co(OH)2 were subsequently used to synthesize LiCoO2, LiNiO2 and CoO, for use as cathodes in ion-Li batteries. The anodes and recycled materials were characterized by analytical techniques.