摘要
以氯化钕溶液为原料液,碳酸氢铵为沉淀剂,采用正加沉淀法和并流沉淀法的加料方式制备了碳酸钕,经高温焙烧后得到氧化钕。运用XRD、SEM、粒度分析等表征手段,考察了加料方式、沉淀剂浓度、晶种、沉淀温度和沉淀时间对氧化钕的粒度、形貌、晶型、稀土总量(REO)和Cl;含量等理化性能的影响。结果表明,45℃~60℃的沉淀温度,所制备碳酸钕沉淀的晶相结构均为Nd_(2)(CO_(3))_(3)·2.5H_(2)O。升高沉淀温度或者延长沉淀时间均可以将氧化钕粉体的形貌由分散的针状结构逐渐演变成具有花束状结构的团聚体。根据不同的沉淀条件,可以制备出不同粒度范围的氧化钕粉体,即采用并流沉淀法的加料方式,通过升高沉淀温度、延长沉淀时间和添加晶种,易制得大粒度氧化钕产品(D_(50)>15μm);采用正加沉淀法的加料方式,通过低温、缩短沉淀时间,易制得小粒度氧化钕产品(D_(50)<15μm)。
Neodymium carbonate was prepared from neodymium chloride solution as raw material and ammonium bicarbonate as precipitant by the way of positive addition precipitation and parallel flow precipitation.After calcination at high temperature,neodymium oxide was obtained.The effects of feeding method,precipitant concentration,crystal seed,precipitation temperature and precipitation time on the physical and chemical properties of neodymium oxide,such as particle size,morphology,crystal form,total rare earth(REO)and Cl;content,were investigated by means of XRD,SEM and particle size analysis.The results show that the crystal structure of neodymium carbonate is Nd_(2)(CO_(3))_(3)·2.5 H_(2)O at 45℃~60℃.Increasing the precipitation temperature or prolonging the precipitation time can change the morphology of neodymium oxide powder from the dispersed needle structure to the cluster structure.According to different precipitation conditions,neodymium oxide with different physical and chemical properties can be prepared,namely neodymium oxide with large particle size(D_(50)>15μm)can be easily prepared by the way of parallel flow precipitation,increasing precipitation temperature,prolonging precipitation time and adding crystal seeds;In contrast,it is easy to produce neodymium oxide with small particle size(D_(50)<15μm)by the way of positive addition precipitation,reducing precipitation temperature,shorten precipitation time.
作者
赵文怡
朱悦然
李净岩
申孟林
张光睿
ZHAO Wen-yi;ZHU Yue-ran;LI Jing-yan;SHEN Meng-lin;ZHANG Guang-rui(State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China;School of Chemical Engineering&Technology,Tianjin University,Tianjin 300350,China)
出处
《稀土》
CAS
CSCD
北大核心
2021年第6期72-79,共8页
Chinese Rare Earths
关键词
氧化钕
碳酸钕
沉淀法
粒度
稀土总量
CL
含量
形貌
neodymium oxide
neodymium carbonate
precipitation method
particle size
rare earth taste
Cl-content
morphology
