查看更多>>摘要：The present work aims to investigate the recovery of light rare earth elements(LREEs)oxides from end-of-life NiMH batteries using a hydrometallurgical process followed by effective precipitation.The operational leaching parameters such as phosphoric acid concentration,temperature,and the solid-liquid ratio were first optimized by Box-Behnken design.The results reveal that under optimum conditions([H3PO4]=2 mol/L,T=80 ℃,and S/L=1∶10 g/mL)the leaching efficiencies of Ni,Co reach 98.1％and 99.3％.While La,Ce,and Nd elements remain in the leaching residue as(La,Ce,Nd)PO4 with yields of 98.2％,98.6％,and 99.6％for La,Ce,and Nd,respectively.Afterward,the(La,Ce,Nd)PO4 is leached with HCl acid,then the rare earth oxalate was precipitated using oxalic acid at a pH of 1.8 and then the product was calcined at 800 ℃ for 2 h in order to synthesize the(Nd,La,Ce)2O3.The analysis using scanning electron microscopy(SEM)coupled with energy dispersive X-ray spectroscopy(EDX)confirms the homogeneity of(Nd,La,Ce)2O3 particles that have two morphologies,i.e.,flower and sticks with a particle size between 3 and 6 μm.The unit cell parameters of(Nd,La,Ce)2O3 were calculated after Rietveld refinement of the XRD patterns,in the space group of Fm-3m are a=b=c=0.57921 nm and the volume equal to 0.194322 nm3.
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