摘要
作为稀土工业的原料,稀土精矿中稀土总量的测定方法步骤多、流程长。实验采用熔融制样-X射线荧光光谱法测定轻稀土精矿中稀土总量,研究了制样和测量条件。准确称取6.000 0g无水四硼酸锂和偏硼酸锂混合熔剂(质量比2∶1)于铂黄坩埚中,以0.500 0g硝酸锂为氧化剂消除试样中还原物质对铂黄坩埚的侵蚀,称取0.600 0g稀土精矿试样,再于试样表面均匀覆盖0.500 0g氧化硼防止试样喷溅,滴加0.5mL 20mg/mL的溴化铵溶液作为脱模剂。将坩埚放进预加热到1 050℃的熔样机内熔融19min制备样片,可消除矿物效应、粒度效应及表面效应。通过各稀土元素X射线荧光谱线的选择减少谱线干扰,以经验系数法校正谱线干扰和基体效应,用稀土精矿标样建立各稀土元素校准曲线。各组分校准曲线的相关系数在0.991~0.999之间,试样重复测量的相对标准偏差(RSD)小于0.5%,稀土总量测定结果与重量法一致。方法的精密度和正确度能够满足生产要求。
The rare earth concentrate is the raw material for rare earth industry.The methods for determination of total rare earths in rare earth concentrate usually have complicated steps and long procedures.The total content of rare earths in light rare earth concentrate was determined by X-ray fluorescence spectrometry（XRF）with fusion sample preparation.The conditions for sample preparation and determination were explored.6.0000 g of anhydrous lithium tetraborate-lithium metaborate mixed flux（mass ratio of 2∶1）was accurately weighed and transferred into platinum-gold crucible.0.5000 g of lithium nitrate was used as oxidizing agent to eliminate the erosion of platinum-gold crucible by the reducing substances in sample.0.6000 g of rare earth concentrate sample was weighed.Then 0.5000 g of boron oxide was uniformly covered on sample surface to prevent sample from spattering.0.5 mL of 20 mg/mL ammonium bromide solution was dropwise added as the releasing agent.The crucible was placed into sample fusion machine which had been preheated to 1050℃.The sample was melted for 19 min to prepare the wafer.Thus the mineral effect,ranularity effect and surface effect could be eliminated.The spectral lines of rare earth elements were properly selected to reduce the spectral interference.The spectral interference and matrix effect were corrected with empirical coefficient method.The calibration curves of rare earth elements were established using the certified reference materials of rare earth concentrate.The correlation coefficients of calibration curves were between 0.991 and 0.999 for all components.The relative standard deviation（RSD）was less than 0.5%.The determination results of total rare earths were consistent with those obtained by gravimetric method.The precision and accuracy of method could meet the production requirements.
作者
蒋天怡
吴文琪
张术杰
任旭东
杜梅
JIANG Tian-yi;WU Wen-qi;ZHANG Shu-jie;REN Xu-dong;DU Mei(National Engineering Research Center of Rare Earth Metallurgy and Functional Materials,Baotou Research Institute of Rare Earth,State Key Laboratory of Bayunobo Rare Earth Resource Researches and Comprehensive Utilizatio)
出处
《冶金分析》
CAS
CSCD
北大核心
2017年第12期27-32,共6页
Metallurgical Analysis
关键词
X射线荧光光谱法(XRF)
熔融法
稀土总量
轻稀土精矿
X-ray fluorescence spectrometry（XRF）
fusion sample preparation
total rare earths
light rare earth concentrate
