This work investigates the influence of the physicochemical characteristics of heavy (17.5 °API), medium (28.3 °API) and blend (50% heavy + 50% medium) crude petroleum on corrosion of AISI 1020 carbon steel at 25.0 ± 1.0°C. The corrosion resistance of steel was analyzed by electrochemical impedance spectroscopy, potentiodynamic polarization, and scanning electron microscopy. The electrochemical results and the micrographs show that the corrosion on steel surfaces after contact with the heavy oil is lesser than medium and blend petroleum, although the heavy oil presents a higher amount of total acid number, sulfur compounds and salt. On steel sample immersed in heavy oil, a localized pitting corrosion was identified, while on samples immersed in medium and blend petroleum was found evidence of pitting and alveolar corrosion.

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.

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.