The of Precipitate-Flotation as New Route for Mixed Oxides Precursors Obtaining

摘要

The paper deal, with a non-conventional procedure for La_x-Ba_y-Cu_z-O_(6+σ) synthesis using model solutions as source for La(Ⅲ) and Cu(Ⅱ). The precursors for the mixed oxides were the complex compounds isolated in La(Ⅲ)-Ba(Ⅱ)-Cu(Ⅱ)-dodecylamine systems subjected to precipitate flotation (DAF technique). The precipitate flotation method allows the separation of the hidroxospecies in the presence of certain quantities of tensioactive species having a double role both as surfactants and ligand. This separation method in aqueous systems ensure both the removal of metallic ions (% R>98) with residual concentration less than 1mg/L and their separation in the form of mixed oxides precursors. The optimum conditions for precursors obtaining have been established: flotation pH, contact time, reagent sequence metallic ions/dodecylamine molar ratio and thermal parameters. The polynuclear complex precursors and the mixed oxides obtained have been characterised by: chemical analysis, FT-IR, EPR, and electronic spectra, thermal and X-ray diffraction analysis. The experimental data confirmed the complex species formatio and proved to be mixed oxides precursors, obtaining.