Current Status and Development Recommendations of Chinese Rare Earths National Certified Reference Materials

Certified reference materials (CRMs) are essential physical standards for measurement and quality control in the testing field. To gain a better understanding of the development status of national certified reference materials for rare earths and to guide the construction of a comprehensive system of national certified reference materials for rare earths to support the high-quality development of the industry. This paper systematically reviewed and analyzed Chinese rare earth national CRMs in terms of types, quantities, research fields and research establishments. As of January 2024, over 197 rare earth national CRMs have been prepared across nine fields, including steel and non-ferrous metals. More than 40 research establishments. Specifically, the categories of CRMs include 28 for rare earth ore and ore products and enriched materials, 29 items of rare earth metals and other compounds (including rare earth separation and smelting products), 6 items of rare earth alloys, 17 items of rare earth functional materials, 21 items of rare earth application products, 3 items of rare earth recyclable materials, and 93 items of other rare-earth-containing materials. This paper identifies the existing problems concerning limited category coverage, and a low number of certified elements in value in the development of Chinese rare earth national CRMs. And propose targeted recommendations for future development: Firstly, it is crucial to supplement the development of national CRMs for existing magnetostrictive materials, rare earth polymer additives, rare earth nickel alloys, rare earth zinc alloys, and other rare earth functional and applied materials, it is essential to develop corresponding national certified reference materials. This will ensure that the development of rare earth new materials and application materials is closely tracked, thereby facilitating the timely creation of relevant national certified reference materials to support the rapid advancement of rare earth new materials and their applications. The second objective is to develop a series of rare earth products based on varying chemical composition ratios, formulate national CRMs that fill the gaps in existing grades, and ensure comprehensive coverage of product quality. The third objective is to create national CRMs containing non-rare earth element reference data for raw material products such as rare earth minerals, metals, and compounds, with the aim of meeting the differentiated requirements of downstream products.