The Use Of Rare Earth Metals

The Use of Rare Earth Metals
In 1980, the production volume of rare earth products worldwide was approximately 34000 tons (calculated by oxides), mainly used in industries such as metallurgy, petrochemical, glass ceramics, fluorescence, and electronic materials. World consumption distribution ratio over the years (excluding China).
Rare earth metals and their alloys play a role in deoxygenation and desulfurization in steelmaking, reducing the content of both to below 0.001%, changing the morphology of inclusions, refining grains, and improving the processing performance of steel, enhancing strength, toughness, corrosion resistance, and oxidation resistance. Rare earth metals and their alloys are used to manufacture ductile iron, high-strength gray iron, and vermicular graphite cast iron, which can change the morphology of graphite in cast iron, improve casting technology, and enhance the mechanical properties of cast iron (alloy steel, cast iron). Adding a small amount of rare earth metals in the smelting of bronze and brass can improve the strength, elongation, heat resistance, and conductivity of the alloy. Adding 1-1.5% rare earth metals to cast aluminum silicon alloys can improve high-temperature strength. Adding rare earth metals to aluminum alloy wires can improve tensile strength and corrosion resistance. Adding 0.3% rare earth metals to Fe-Cr-Al electric heating alloy can improve oxidation resistance, increase resistivity, and high-temperature strength. Adding rare earth metals to titanium and its alloys can refine grain size, reduce creep rate, and improve high-temperature corrosion resistance.
Microspherical molecular sieves prepared from cerium mixed rare earth chlorides and lanthanum rich rare earth chlorides are used in petroleum catalytic cracking processes. Rare earth metal and transition metal composite oxide catalysts are used for gas purification, which can convert carbon monoxide and carbon hydride into carbon dioxide and water. The praseodymium neodymium naphthenic acid alkyl aluminum chloride alkyl aluminum ternary system catalyst is used for the synthesis of rubber.
Rare earth polishing powder is used for polishing various glass devices, while CeO2 is used for glass decolorization while improving its transparency; Pr6O11, Nd2O3, etc. are used for glass coloring; La2O3, Nd2O3, CeO2, etc. are used in the manufacturing of special glass; Rare earth elements can be used in the ceramic industry to manufacture ceramic glaze, refractory materials, and ceramic materials. Single high-purity rare earth oxides such as Y2O3, Eu2O3, Gd2O3, La2O3, Tb4O7 are used to synthesize various fluorescent materials, such as red fluorescent powder for color television, white fluorescent powder for projection television, ultra short afterglow fluorescent powder, various fluorescent powders for lamps, fluorescent powders for X-ray intensifying screens, and fluorescent materials for light conversion. Rare earth metal iodides are used in the manufacturing of metal halide lamps, with a luminous efficiency of 80-100 lumens/watt and a color temperature of 5500-6000K, which is close to sunlight. They can replace carbon rod arc lamps as lighting sources. High purity Y2O3, Nd2O3, Ho2O3, and Gd2O3 are excellent laser materials.
The rare earth cobalt hard magnetic alloy prepared with rare earth metals has the advantages of high remanence and high coercivity. Yttrium iron garnet (YIG) ferrite is a single crystal or polycrystalline ferromagnetic material made from high-purity Y2O3 and iron oxide. They are used for microwave devices such as YIG devices. High purity Gd2O3 is used to prepare gadolinium gallium garnet (GGG), and its single crystal is used as a substrate for magnetic bubbles.