Synthesis of GdF_3 from the Gd_2O_3-NH_4HF_2 system

作     者：HAO Zhanzhong ZHANG Jianliang WANG Bin ZHANG Xidong 

作者机构：Metallurgical and Ecological Engineering School University of Science and Technology Beijing Beijing 100083 China Baotou Teachers College Baotou 014030 China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2007年第26卷第5期

页      面：482-487页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 0806[工学-冶金工程] 08[工学] 0817[工学-化学工程与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 070301[理学-无机化学] 0702[理学-物理学] 

主　　题：inorganic chemistry Gd NH4HF2 synthesis 

摘      要：GdF3 was synthesized with Gd2O3 and NH4HF2 under atmospheric pressure and vacuum. The effects of pressure,temperature,and reactant ratio on the reaction process were investigated. A new mechanism for the synthesis of GdF3 was proposed. Powdered Gd2O3 started to react with NH4HF2 at low temperature,and the products were GdNH4F4,NH4F,NH3,and H2O. GdNH4F4 decomposed to GdF3 and NH4F after further high-temperature treatment,accompanying the volatilization and decomposition of NH4F. The whole process could be divided into three steps： synthesis,decomposition,and deamination. The initial and final reaction temperatures decreased under vacuum condition. An optimized process for the preparation of GdF3 was obtained： synthesis under atmospheric pressure at low temperature and decomposition and deamination under vacuum at high temperature.