Mechanism of CeMgAl11O19:Tb3+ alkaline fusion with sodium hydroxide
来源期刊：Rare Metals2015年第3期
论文作者：Hu Liu Shen-Gen Zhang De-An Pan Yi-Fan Liu Bo Liu Jian-Jun Tian Alex A.Volinsky
文章页码：189 - 194
摘 要：Comprehensive CeMgAl11O19:Tb3+（CTMA）disintegration via alkaline fusion was discussed. The rare earth（RE） elements in CTMA were dissolved by HCl completely after alkaline fusion. Relationships between the alkaline fusion temperature and various properties of the compounds were examined by various techniques to elucidate their roles in the expected CTMA disintegration.X-ray diffraction（XRD） analysis indicates the phase transformation sequence. A scientific hypothesis of crystal structure disintegration presents that sodium ions substitute for the europium and barium ions in the mirror plane and magnesium ions in the spinel block successively, resulting in that more oxygen vacancies and interstitial sodium ions appear. The unit cell [P63/mmc（194）] breaks from the mirror plane. Then it is decomposed into Na Al O2, and magnesium, cerium, and terbium ions combine with free OH-into Mg O, Tb2O3 and CeO2;Tb2O3 and CeO2 change into Ce0.6Tb0.4O2-x. In the end, the rare earth oxide is recycled easily by the acidolysis. The mechanism provides fundamental basis for recycling of REEs from waste phosphors.
Hu Liu1，Shen-Gen Zhang1，De-An Pan1，Yi-Fan Liu1，Bo Liu1，Jian-Jun Tian1，Alex A.Volinsky2
1. Institute for Advanced Materials and Technology,School of Materials Science and Engineering,University of Science and Technology Beijing2. Department of Mechanical Engineering,University of South Florida
摘 要：Comprehensive CeMgAl11O19:Tb3+（CTMA）disintegration via alkaline fusion was discussed. The rare earth（RE） elements in CTMA were dissolved by HCl completely after alkaline fusion. Relationships between the alkaline fusion temperature and various properties of the compounds were examined by various techniques to elucidate their roles in the expected CTMA disintegration.X-ray diffraction（XRD） analysis indicates the phase transformation sequence. A scientific hypothesis of crystal structure disintegration presents that sodium ions substitute for the europium and barium ions in the mirror plane and magnesium ions in the spinel block successively, resulting in that more oxygen vacancies and interstitial sodium ions appear. The unit cell [P63/mmc（194）] breaks from the mirror plane. Then it is decomposed into Na Al O2, and magnesium, cerium, and terbium ions combine with free OH-into Mg O, Tb2O3 and CeO2;Tb2O3 and CeO2 change into Ce0.6Tb0.4O2-x. In the end, the rare earth oxide is recycled easily by the acidolysis. The mechanism provides fundamental basis for recycling of REEs from waste phosphors.
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