The Research Of Leaching Separation On Extracted Vanadium Residue And Preparation Of Lithium-ion Battery Electrode Materials

With the increasingly serious environmental pollution and the growing shortage of resources, the recycling of waste materials has become the focus of research in worldwide attention. Especially in the rapid development of steel industry, on the one hand, it consumes a lot of resources and energy, on the other hand, it has produced a large number solid waste, which caused some damage to the ecological environment. In this paper, we consider the material, energy and environmental protection, propose a new way to prepare lithium-ion battery cathode material LiFePO4and anode material Li4Ti5O12from extracted vanadium residue.The elements of extracted vanadium residue are selectively leached by hydrochloric acid at atmospheric pressure, detected each kind of element by the method of chemical analysis. We designed orthogonal experiments at first, and made single factor variable experiments based on this, studied the leaching rate of each element on different levels in these factors:the concentration of hydrochloric acid, solid-liquid ratio, leaching time and temperature. and determined the optimum leaching process:30wt%of the hydrochloric acid concentration,2.75:1of the acid residue ratio,100℃of the temperature,3h of the leaching time. In this situation, the leaching ratio of Fe was95.69%, the leaching ratios of Mg, Mn, Ca, Al are all nearly90%, the leaching ratio of Ti is7.42%, and Si is almost not leached.The precursor was prepared by selectively precipitating leaching solution with H3PO4, and determined the ratio of Fe:P in the precursor by chemical analysis. The Fe:P of the precursor in the optimum experiment is0.996, so close to the theoretical value. XRD patterns indicate that the precursor FePO4containing a small amount of impurities. Then prepared lithium-ion battery cathode material LiFePO4that contain a small amount of metal doped by carbon thermal reduction method. Compared with different XRD patterns, found that the Fe:P of the precursor is closer to1, the purity of LiFePO4is higher. The first discharge capacity at0.1C was109.2mAh/g, the battery has a good cycle performance, the capacity retention rate is more than95%after50cycles at0.1C.In sulfuric acid medium, titanium is leachcd selectively from the residue after leached through H2O2-NH3·H2O system, under the optimal conditions the leaching ratio of Ti is84.23%. Calcined the peroxo titanium compound under800℃, the product was TiO2that containing a small amount of impurity, then used it as precursor prepared Li4Ti5O12by solid-phase method, the optimum temperature of the reaction is800℃. The first discharge capacity of the battery is163.3mAh/g.