15 kA稀土熔盐电解槽炉底结瘤形成机制与对策  

Formation mechanism and countermeasures of nodules at furnace bottom of 15 kA rare earth molten salt electrolysis cell

作　　者：伍永福[1] 马守营 王振峰 边雪[2] 刘中兴[1] 柳云龙 WU Yongfu;MA Shouying;WANG Zhenfeng;BIAN Xue;LIU Zhongxing;LIU Yunlong(School of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,China;School of Metallurgy,Northeastern University,Shenyang 110004,China;Sichuan Jiangtong Rare Earth Co.Ltd.,Mianning 615601,China)

机构地区：[1]内蒙古科技大学能源与环境学院,内蒙古包头014010 [2]东北大学冶金学院,辽宁沈阳110004 [3]四川江铜稀土有限责任公司,四川冕宁615601

出　　处：《中国有色冶金》2023年第4期81-87,共7页China Nonferrous Metallurgy

基　　金：国家自然科学基金(51964039);内蒙古自然基金(2022LHMS05004,2021GG0103);白云鄂博稀土资源研究与综合利用国家重点实验室开放基金(2021H2275)。

摘　　要：稀土金属镨钕合金生产过程中,易在熔盐电解槽炉底形成结瘤,不但影响生产的连续化,还对产品质量产生影响,目前相关文献多集中在结瘤产物成分及电解参数对结瘤的影响方面,鲜有文献对结瘤形成机理进行研究。本文分析了炉底结瘤物形貌和结晶物组成,发现结瘤物的成分为氧化钕、氧化镨、氟氧化钕以及少量氟化钕和金属钕。采用数值模拟的方法对电解流场进行了分析,得出炉底结瘤物形成原因:加料速度过快是形成结瘤物的主要原因,氟氧化钕的熔点比熔盐高,易在石墨坩埚台阶上沉积形成结瘤物;稀土金属出炉时会带走大量的热,导致炉底温度出现较大变化,氧化钕在温度较低的区域容易析出,沉积在石墨坩埚台阶上;电解槽底部区域熔盐的流动性较差,使得在石墨坩埚台阶上析出的产物不能随熔盐流动而沉积。通过控制下料速度和保持合理电解温度,可以避免过剩的物料或者析出物料在坩埚台阶上沉积,及时清理炉底和台阶上积料可以控制结瘤物的增长速度。In the production process of rare earth metal praseodymium neodymium,it is easy to form nodules at the bottom of the molten salt electrolytic cell,which not only affects the continuity of production,but also affects the product quality.At present,most of the related literatures focus on the composition of nodules and the influence of electrolytic parameters on nodules.Few literatures have studied the mechanism of nodule formation.In this paper,the morphology and crystal composition of the furnace bottom nodule are analyzed.It is found that the composition of the nodule is neodymium oxide,praseodymium oxide,neodymium oxyfluoride and a small amount of neodymium fluoride and metal neodymium.The numerical simulation method was used to analyze the electrolytic flow field,and the reason for the formation of nodules at the bottom of the furnace was obtained.The main reason for the formation of nodules is that the feeding speed is too fast,and the melting point of neodymium oxyfluoride is higher than that of molten salt,and it is easy to deposit on the steps of graphite crucible to form nodules.Rare earth metals will take away a lot of heat when they leave the furnace,resulting in a large change in the temperature of the furnace bottom,and neodymium oxide is easy to precipitate in the lower temperature area and deposit on the steps of graphite crucible.The fluidity of the molten salt at the bottom of the electrolytic cell is poor,so that the products precipitated on the steps of the graphite crucible cannot be deposited with the flow of the molten salt.By controlling the feeding speed and maintaining a reasonable electrolysis temperature,excess materials or precipitated materials can be avoided to deposit on the crucible step.The growth rate of nodules can be controlled by cleaning the bottom of the furnace and the accumulated materials on the step in time.

关 键 词：稀土熔盐电解 镨钕合金 结瘤物 形成机制 数值模拟 加料速度 电解温度 氧化钕析出 

分 类 号：TF845[冶金工程—有色金属冶金] TF803.27