RESUMO
With the widespread use of lithium-ion batteries, the cumulative amount of used lithium-ion batteries is also increasing year by year. Since waste lithium-ion batteries contain a large amount of valuable metals, the recovery of valuable metals has become one of the current research hotspots. The research uses electrometallurgical technology, and the main methods used are cyclic voltammetry, square wave voltammetry, chronoamperometry and open circuit potential. The electrochemical reduction behavior of Ni3+ in NaCl-CaCl2 molten salt was studied, and the electrochemical reduction behavior was further verified by using a Mo cavity electrode. It is determined that the reduction process of Ni3+ in LiNiO2 is mainly divided into two steps: LiNiO2 â NiO â Ni. Through the analysis of electrolysis products under different conditions, when the current value of LiNiO2 is not less than 0.03 A, the electrolysis product after 10 h is metallic Ni. When the current reaches 0.07 A, the current efficiency is 77.9%, while the Li+ in LiNiO2 is enriched in NaCl-CaCl2 molten salt. The method realizes the separation and extraction of the valuable metal Ni in the waste lithium-ion battery.
RESUMO
Hexagonal Zn(0.9)Mg(0.1)TiO(3) (ZMT) composite fibers were successfully prepared by combining sol-gel with an electrospinning and calcination technique. The crystalline phase and microstructures of Zn(0.9)Mg(0.1)TiO(3) fibers, calcined at various temperatures for 1 h, were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetry differential thermal analysis (TG-DTA) techniques. The results showed that the crystalline phase, morphology and grain size of the ZMT fibers were influenced by the calcination temperature and the doped magnesium improved the stability of the ilmenite ZnTiO(3)-based ceramic. Fibrous, linked particles and separated hexagonal particles were obtained after being calcined at 500, 700 and 900 °C, respectively. The single phase Zn(0.9)Mg(0.1)TiO(3) was formed from 700 °C to 900 °C and the possible formation mechanism was proposed. The as-prepared samples exhibited low activities for Methylene blue (MB) photodegradation under visible-light irradiation.
RESUMO
A simple and high-yield synthetic route was developed to synthesize the different-shaped PbTiO3 powders. Spherical, rod, and cubic shapes of PbTiO3 were achieved from the precursors of spherical and rod TiO2/K2Ti4O9 compounds with PbO in the NaCl-KCl melts at the temperatures from 700 to 900 degrees C, respectively. Raman spectroscopy, X-ray diffraction, thermal field emission scanning electron microscopy, and transmission electron microscopy were used to investigate the structure and morphology. Moreover, the formation mechanism of PbTiO3 with controlled morphologies was analyzed. PbO diffused to the TiO2 surface in the molten salts, followed with the nucleation and growth of PbTiO3; thus, morphology control of PbTiO3 was realized through controlling the shapes of the titanium source. Raman spectra of the as-synthesized PbTiO3 showed mode-softening behaviors of E(1TO) related to the weakening in ferroelectricity.
