The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is ...The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.展开更多
Waste management of rare earth metals（REMs） containing materials and recycling of rare earth metals（REM） from waste materials are becoming more and more important due to high demand and resource exhaustion. Howeve...Waste management of rare earth metals（REMs） containing materials and recycling of rare earth metals（REM） from waste materials are becoming more and more important due to high demand and resource exhaustion. However, extraction of REM from waste fluorescent powder materials is difficult because of their special aluminate structure. A novel ＂alkaline roasting-acid leaching＂ process was developed in this study. The alkaline roasting process mechanism was examined using differential thermal analysis（DTA）-thermogravimetric（TG） measurements, and the roasting product was characterized by XRD analysis. In this process, Al_2O_3 was converted into water soluble NaAlO_2 via alkaline roasting, and NaAlO_ 2 in the roasting product could be easily dissolved in water, while the rare earth oxide（REOs） remained as solid. After filtration, REOs cake was leached using hydrochloric acid to achieve 99.8% of REM recovery. It was concluded that the alkaline roasting-acid leaching process could effectively separate Al_2O_3 and REOs with high REM recovery.展开更多
基金supported by the National Hi-Tech R&D Program of China (No. 2012AA063202)National Key Project of Scientific and Technical Support Program of China (Nos. 2011BAE13B07, 2012BAC02B01, and 2011BAC10B02)National Natural Science Foundation of China (Nos. 51174247 and 50972013)
文摘The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.
基金Supported by National Natural Science Foundation of China(51464012)Natural Science Foundation of Jiangxi(20114 bab206031)the Natural Science Foundation of Jiangxi University of Science and Technology(NSFJ2015-G09)
文摘Waste management of rare earth metals（REMs） containing materials and recycling of rare earth metals（REM） from waste materials are becoming more and more important due to high demand and resource exhaustion. However, extraction of REM from waste fluorescent powder materials is difficult because of their special aluminate structure. A novel ＂alkaline roasting-acid leaching＂ process was developed in this study. The alkaline roasting process mechanism was examined using differential thermal analysis（DTA）-thermogravimetric（TG） measurements, and the roasting product was characterized by XRD analysis. In this process, Al_2O_3 was converted into water soluble NaAlO_2 via alkaline roasting, and NaAlO_ 2 in the roasting product could be easily dissolved in water, while the rare earth oxide（REOs） remained as solid. After filtration, REOs cake was leached using hydrochloric acid to achieve 99.8% of REM recovery. It was concluded that the alkaline roasting-acid leaching process could effectively separate Al_2O_3 and REOs with high REM recovery.
