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Analysis Scheme for Rare Earth Impurity Elements 5800 in Neodymium Iron Boron
Date: 2025-12-10Read: 0
Neodymium iron boron, as a high-performance permanent magnet material, is widely used in fields such as new energy vehicles, wind power equipment, electronic information, aerospace, etc. It is a key foundational material supporting energy conservation and environmental protection, high-end manufacturing, and the development of emerging industries. And its internal rare earth impurity elements have clear limit requirements, which are reflected in domestic industry standards and export control policies, as well as constrained by international market regulations. At the same time, some high-end application scenarios also have more stringent customization standards. The relevant announcement of the Ministry of Commerce in 2025 clearly states that neodymium iron boron permanent magnet materials containing Tb and Dy are subject to export control; Magnets with a total rare earth content of ≥ 25%, or a single medium heavy rare earth (such as dysprosium and terbium) content of ≥ 0.1%, must submit a license and third-party testing report when exporting. In the industry standard XB/T 617.2-2014 "Chemical Analysis Methods for Neodymium Iron Boron Alloys", Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) is defined as the first method, which uses matrix matching to detect rare earth elements in neodymium iron boron.
This article introduces a detection method using Agilent 5800 ICP-OES rapid automatic curve fitting technology (FACT) for accurate determination of rare earth impurity elements in neodymium iron boron.This method uses FACT, which can effectively remove spectral line interference between rare earth elements. After model calibration, the correlation coefficients of all element calibration curves are greater than 0.999, and the determination results of 13 rare earth impurity elements are basically consistent with the ICP-MS/MS results. The specific experimental details are as follows:
instrument
Adopting Agilent 5800 ICP-OES, equipped with a sea spray atomizer and dual channel swirl chamber, as well as a fully detachable torch tube assembly with a 1.8mm center tube. Use Agilent ICP Expert software (version 7.7.3) to control the instrument, which includes FACT function, comprehensive quality control (QC), intelligent semi quantitative and spectral line five-star recommendation function (InteliQuant), interference judgment and data screening functions.
Instrument conditions
Results and Discussion
Selection of wavelength and calibration concentration range for the tested element
The IQ function of this software integrates powerful analysis and intelligent decision-making capabilities. It can not only accurately determine the proportion and basic content of each component in the sample, but also visualize it in different intuitive and eye-catching colors, helping users quickly identify element characteristics and scientifically and reasonably select the concentration setting range of each element. In addition, the IQ function can intelligently analyze and automatically recommend the optimal wavelength of the tested element based on the specific composition of the sample, accurately avoiding the interference of high content elements in the sample, completely bidding farewell to the tedious traditional manual screening process, significantly improving analysis efficiency and accuracy, and bringing users a more convenient and efficient detection experience.
Figure 1 Semi quantitative and Five star Spectral Line Recommendation Function of Intelligent IQ
FACT provides real-time spectral correction through the use of advanced spectral modeling techniques, which can mathematically resolve (i.e. separate) analyte signals from raw spectra and model them by separately measuring expected components and their respective responses. For example, when it is necessary to determine La (408.671 nm) in neodymium iron boron, it is often interfered by the spectral line of Nd408.680 nm. By establishing a FACT model with blank, single standard La and single standard Nd, the correct analyte signal can be effectively separated to ensure the accuracy of the test results, as shown in the following figure.
To eliminate matrix interference, the calibration curve configuration was matched with the matrix according to the "Chemical Analysis Method for Neodymium Iron Boron Alloy". The final selected element wavelength, calibration concentration point, and background correction method are shown in Table 2. According to the table, the correlation coefficients of the calibration curves for the 13 rare earth impurity elements analyzed are all higher than 0.999.
Table 2 Analysis of Element Wavelength and Linear Range
Method detection limit and spiked recovery experiment
Conduct testing on the processed neodymium iron boron samples and simultaneously test the detection limits of the instrument and method (under preset method parameter conditions, perform 11 measurements on blank samples, define three times the standard deviation as the instrument detection limit, and multiply the instrument detection limit by the dilution factor during the previous processing as the method detection limit). To verify the feasibility of the method, further spiked recovery experiments were conducted, and the experimental results are shown in Table 3. The results indicate that the recovery rates of 13 rare earth impurity elements range from 90.4% to 111.3%, fully demonstrating the good accuracy and reliability of this method.
Table 3 Detection limits and spiked recovery rates of each element
Accuracy of sample analysis results
To verify the accuracy of the test results, in addition to the spiked recovery experiment mentioned above, the test results of 5800 were compared with those of Agilent 8900 ICP-MS/MS. The results are shown in Table 4. From this table, it can be seen that:After using FACT for calibration, the test results of 5800 and 8900 are basically consistent, indicating that it completely eliminates interference and the test results are accurate and reliable.
Table 4 Comparison of Agilent 5800 and 8900 Test Results
Conclusion
This article uses Agilent 5800 and its unique FACT function to detect 13 rare earth impurity elements in neodymium iron boron samples.In the presence of matrix interference, the instrument detection limit of all tested elements is less than 5ppb, and the spiked recovery rate is between 90.4% and 111.3%. The difference between the FACT analysis results and ICP-MS/MS results is minimal, indicating that the developed method has high sensitivity and accuracy, and can achieve precise quantitative analysis of rare earth impurities in neodymium iron boron samples.