raseodymium is a metal element, a rare earth metal. The name of the
element comes from Greek, and the original meaning is "green". The
crystal structure is a hexagonal unit cell. The corrosion resistance of
praseodymium in the air is stronger than that of lanthanum, cerium,
neodymium and europium, but it will produce a fragile green oxide when
exposed to the air. Pure praseodymium must be stored in mineral oil or
sealed plastic. One of the uses of praseodymium is for the catalytic
cracking of petroleum. In the form of neodymium praseodymium enrichment,
it is added to Y-type zeolite molecular sieve to prepare petroleum
cracking catalyst, which can improve the activity, selectivity and
stability of the catalyst.
Praseodymium can be used as a catalyst in petrochemical industry. As a large amount of rare earth elements, a large part of them are used in the form of mixed rare earths, such as purification and modifiers for metal materials, chemical catalysts, and agricultural rare earths. In the form of neodymium praseodymium enrichment, it is added to Y-type zeolite molecular sieve to prepare petroleum cracking catalyst, which can improve the activity, selectivity and stability of the catalyst. As a plastic modification additive, adding praseodymium and neodymium enrichment to polytetrafluoroethylene (PTFE) can significantly improve the wear resistance of PTFE.
Rare earth permanent magnet materials are the current rare earth application field. The performance of praseodymium alone as a permanent magnetic material is not outstanding, but it is an excellent synergistic element that can improve the magnetic properties. Whether it is the first generation rare earth permanent magnet material samarium cobalt permanent magnet alloy or the third generation rare earth permanent magnet material neodymium iron boron, adding an appropriate amount of praseodymium can effectively improve and improve the performance of the permanent magnet material. For example, adding part of Pr to replace Sm in SmCo5 can increase the magnetic energy product of permanent magnetic materials. The ratio of the two is generally 80% Sm-20% Pr. If praseodymium is added too much, it will reduce the coercivity and stability of the material. In the third-generation rare earth permanent magnet material neodymium iron boron, adding praseodymium can increase the coercivity of the material. Germany, Japan and other countries all add part of praseodymium when producing high-coercivity neodymium iron boron magnets. The amount of praseodymium added is 5% to 8%, up to 10%, which can replace 1/3 of neodymium. Magnetic materials have higher requirements for the quality of praseodymium, and should at least reach the same quality as neodymium. The addition of praseodymium can also improve the oxidation resistance (air corrosion resistance) and mechanical properties of the magnet, and has been widely used in various electronic devices and motors.
Pr can also be used for grinding and polishing materials. Pure cerium-based polishing powder is usually light yellow and is a high-quality polishing material for optical glass. It has replaced the iron oxide red powder that has low polishing efficiency and pollutes the production environment. Neodymium oxide has little effect on polishing, but praseodymium has good polishing performance. Rare earth polishing powder containing praseodymium will be reddish brown, also known as red powder, but this red is not iron oxide red, but because it contains praseodymium oxide, the color of rare earth polishing powder becomes darker. Praseodymium is also used for new grinding materials to make praseodymium-containing corundum grinding wheels. Compared with white corundum, the efficiency and durability can be increased by more than 30% when grinding carbon structural steel, stainless steel, and high-temperature alloys. In order to reduce costs, in the past, neodymium praseodymium enrichment was used as raw material, so it is called neodymium praseodymium corundum grinding wheel.
The use of praseodymium in the field of optical fiber is becoming more and more extensive. A praseodymium-doped fiber amplifier (PDFA) has been developed that has an amplifying effect in the 1300~1360nm spectral region, and the technology is becoming more and more mature. PDFA is of great practical significance to the reconstruction and system upgrade of the 1550nm CATV system fiber optic cable TV that is currently being laid in large numbers in China due to its excellent performance-to-price ratio. PDFA will fundamentally change the existing 1550nm CATV network structure, making the 1310nm CATV system an ideal alternative to the 1550nm system in the transformation of HFC systems..