Since the 1980s, the rare earth industry has developed rapidly. Whether abroad or at home, the application technology of rare earth has been extended to all fields of the national economy. China is recognized as a large rare earth country in the world. China’s rare earth industry ranks first in resource reserves, rare earth output, rare earth consumption and rare earth sales in the world. China is the only country in the world that can supply a large number of rare earth products of different varieties and grades, China occupies a dominant and dominant position in the world rare earth market. At present, the total consumption of rare earths in the world is about tons in terms of oxides, accounting for only half of the production. It can be seen that there is great potential for further development and application. Therefore, in the new technological revolution, making more and better use of rare earth to serve the national economy has become a major subject with strategic objectives facing the 21st century.
With the development of rare earth smelting technology, rare earth is more widely used. Especially in metal smelting, rare earth is directly known as the “vitamin” of materials. This is mainly because as long as a small amount or a small amount of rare earth is added in the smelting process, the physical and chemical properties of materials can be well optimized. Industrial production has proved that rare earth inoculants can significantly improve the graphite morphology of gray cast iron and refine the graphite structure. They are an excellent nail fertility agent.
Rare earth can be widely used as modifier in production. Rare earth has strong affinity with sulfur, oxygen, hydrogen, nitrogen and other elements, and its chemical properties are flexible. Rare earth is added in the smelting process. Oxygen, sulfur, nitrogen and other elements in molten iron can react with rare earth to form rare earth sulfide which is difficult to dissolve in molten iron Rare earth nitrides and rare earth oxides have obvious functions of desulfurization, deoxidation and dehydrogenation, change the size, shape and distribution of rare earth non-metallic inclusions, reduce their influence on the microstructure and properties of gray cast iron, and then improve the mechanical properties of gray cast iron. At the same time, adding an appropriate amount of rare earth in the process of refining can effectively improve the casting properties of gray cast iron, reduce the surface cracks, shrinkage cavities, pores and segregation of castings, and improve the surface quality. For a long time, the effect of rare earth on the microstructure and properties of gray cast iron has been improved. The production of nodular cast iron and vermicular cast iron by using rare earth alloy has also been gradually applied to practical production, but the effect of rare earth on the microstructure and properties of low carbon equivalent gray cast iron needs further research.