Recovery of lithium iron phosphate cathode waste by nitric acid-spray pyrolysis method
Pure lithium nitrate solution was obtained by leaching lithium ions with nitric acid and adjusting the pH during iron precipitation.Lithium carbonate powder was prepared by spray pyrolysis.The crystal structure,microstructure and impurity ion content were characterized by X-ray diffraction,scanning electron microscopy and inductively coupled plasma emission spectroscopy.The results show that the leaching rate of lithium ion is 97.47％under the optimum acid leaching conditions with 4 mol/L of nitric acid concentration,at 65℃for 3 h.The conversion of lithium carbonate is more than 99％and its purity is 98.4％under the optimum spray pyrolysis conditions with n(LiNO3):n(CH3OH)=1.0:1.5 of mixed solution and 700℃of pyrolysis temperature.And the obtained product has a spherical shape with good dispersion.This method effectively avoids the introduction of other impurity ions in the recovery process,reduces the cost of impurity removal and washing,and has a high comprehensive recovery of lithium.
lithium iron phosphatenitric acidspray pyrolysislithium carbonate
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