ZnO synthesis from Zn-C and alkaline spent batteries by alkaline leaching: properties and applications

6th EUCHEMS Chemistry Congress. Seville, Spain, 11th-19 th September 2016This report describes the leaching experiments to recover Zn from spent household Zn-C and alkaline batteries. Basic zinc carbonate Zn5(CO3)2(OH)6 nanoparticles have been successfully synthesized by the leaching of an ammoniacal ammonium carbonate solution of black mass. Zinc oxide (ZnO) were prepared by the thermal decomposition of basic zinc carbonate precursor. The synthesis of ZnO micro and nanostructures is carried out through the vapor solid growth process.Ministerio de Economía y Competitividad MINECO (Projects MAT 2012-31959 and CSD2009-00013) and MINECO/FEDER (MAT2015-65274-R; 2016-2019). This work has supported by the Envirobat España S.L.Peer reviewe

SYNTHESIS OF TRICALCIUM ALUMINATE FROM ALUMINIUM DROSS

The present work examines the synthesis of tricalcium aluminate (for use as a synthetic slags) from the dross produced in the manufacture of metallic aluminium in Holding furnaces. Three types of input dross were used with Al2O3 contents ranging from 51 to 82 wt%. Calcium aluminates were formed via the mechanical activation (reactive milling) of different mixtures of dross and calcium carbonate, and sintering at 1200ºC. The variables affecting the process, especially the milling time and the Al2O3:CaO molar ratio, were studied. The final products were examined via DRX, SEM, TEM and Raman spectroscopy, and their chemical composition were compared with those of commercial synthetic slags.Peer reviewe

Synthesis and characterization of ZnO micro-and nanostructures grown from recovered ZnO from spent alkaline batteries

ZnO powders were obtained via thermal decomposition of Zn5(CO3)2(OH)6 precursor, resulting from the ammoniacal leaching of the black mass produced during recycling of spent alkaline batteries. Zn5(CO3)2(OH)6 powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and then calcined under oxidizing conditions resulting in ZnO powders. Transmission electron microscopy (TEM), XRD and Raman spectroscopy of the obtained ZnO indicated wurtzite crystal structure with lattice parameter a value of 0.331 nm, in agreement with the reported value. Photoluminescence (PL) measurements in the visible range showed two main bands centred at 3.01 eV (412 nm) and 2.35 eV (527 nm) and the red range PL spectra showed two bands centred at 1.87 eV (660 nm) and 1.63 eV (760 nm). These emission bands are characteristic of ZnO and normally ascribed to intrinsic defects, related to the stoichiometry of the crystal. Several morphological kinds of ZnO micro- and nanostructures such as micro- and nanorods, nanocombs, nanowires and microfibers were grown by the vapor-solid method (VS). Structures were characterized by SEM, energy-dispersive X-ray spectroscopy (EDS), cathodoluminescence (CL) and Raman spectroscopy.This work has supported by the EnvirobatEspaña S.L and by the Spanish Ministerio de Economía y Competitividad MINECO (Projects MAT 2012–31959 and CSD2009-00013) and MINECO/FEDER (MAT2015-65274-R; 2016–2019). Dr. I. García-Díaz expresses her gratitude to the Ministry of Economy and Competitiveness for their Postdoctoral Junior Grants (Ref. FPDI-2013-16391) contracts co-financed by the European Social Fund. PhD. Ana López Fernández expresses her gratitude to the Comunidad de Madrid for their Technical Junior Grants (Ref. PEJ15/AMB/Al-0049) contracts co-financed by the European Social Fund.Peer Reviewe

Crossed Ga_2O_3/SnO_2 Multiwire Architecture: A Local Structure Study with Nanometer Resolution

Crossed nanowire structures are the basis for high-density integration of a variety of nanodevices. Owing to the critical role of nanowires intersections in creating hybrid architectures, it has become a challenge to investigate the local structure in crossing points in metal oxide nanowires. Thus, if intentionally grown crossed nanowires are well-patterned, an ideal model to the role of impurities in the coupling formation, structural modifications, and atomic site configuration based on crossed Ga_2O_3/SnO_2 nanowires. Our experiment opens new avenues for further local structure studies with both nanometer resolution and elemental sensitivity

Luminescence and gas-sensing properties of ZnO obtained from the recycling of alkaline batteries

The great amount of wasted alkaline batteries produced nowadays constitutes a driving force for obtaining valuable materials from the recycling process. Zn is one of the major components of the batteries residues; hence, the possibility to obtain good quality ZnO appears very attractive. In this work, we have characterized ZnO obtained by different synthesis routes from the black mass produced during the mechanical recycling process. The luminescent behaviour has been studied and compared to that of the commercial ZnO. Chromaticity has been analysed through the corresponding CIE [Commission Internationale d’Eclairage (CIE) 1931] coordinates, obtained from the emission spectra. The possible response to gases from the ZnO obtained from the different sources has been also investigated. While ZnO from recycling does not show an appreciable gas sensitivity, the possibility to follow different calcination routes and hence obtaining ZnO with different defect structures and luminescent behaviour open the way to tailor the colour of the emitted light.This work has been supported by MINECO/FEDER (MAT2015-65274-R; 2016-2019) and Envirobat España S. L. G. Escalante wishes to acknowledge CONACYT for the postdoc Grant I. García-Díaz MINECO/FEDER by the Postdoctoral Junior Grants (Ref. FPDI-2013-16391) contracts co-financed by the European Social Fund.Peer Reviewe

Novel simple methods for the synthesis of single-phase valentinite Sb2O3

Several methods with solid and dissolved reactants were investigated as possible routes for synthesis of single-phase valentinite Sb2O3. The methods are based on simple chemical reaction between SbCl3 and NaOH. The method with solid state reactants was established on self-propagating room temperature reaction (SPRT), while wet syntheses were based on the same chemical reaction, and performed in either distilled water or absolute ethanol. The prepared powders were characterized by X-ray powder diffraction, scanning electron microscopy and field emission scanning electron microscopy, high-resolution transmission electron microscopy, selected area electron diffraction (SAED) and UV/vis diffuse reflectance spectroscopy. SPRT and aqueous solution syntheses resulted in single-phase valentinite Sb2O3, but with significantly different morphologies. In the case of SPRT method the obtained powder contains well crystallized prismatic shaped submicronic particles, with hexagonal or lozenge basis typical for valentinite crystal structure, while aqueous solution synthesis resulted in powder containing micronic agglomerates. The ethanolic solution synthesis product was Sb2O3 with cubic senarmontite as predominant phase and traces of orthorhombic valentinite. It was confirmed that not only the aggregate state, but also the choice of solvent has a great influence on the structural and optical characteristics of synthesized Sb2O3 powders