Rare earths in the earth's crust is not rare, this group of elements of the Clark value of 0.0236%, of which the cerium group of elements for the 0.01592%, yttrium group of elements for the 0.0077%; than the common elements of copper (0.01%), zinc (0.005%), tin (0.004%), lead (0.0016%), nickel (0.008%), cobalt (0.003%). 0.003%), etc. are more.
Below we will specifically talk about the timing of the application of various rare earth elements, in order to better distinguish between light and heavy rare earths:
Lanthanum (La): lanthanum has a wide range of applications, such as applied to piezoelectric materials, electrical and thermal materials, thermoelectric materials, magnetoresistive materials, luminescent materials (orchid powder), hydrogen storage materials, optical glass, laser materials, a variety of alloy materials, etc.. She is also used in the preparation of many organic chemical products in the catalyst, light conversion of agricultural films also use lanthanum, in foreign countries, scientists to lanthanum on the role of crops endowed with "super calcium" reputation.
Cerium (Ce): 1, cerium as a glass additive, can absorb ultraviolet and infrared rays, is now used in large quantities in automotive glass. Not only can it prevent ultraviolet rays, but also reduce the temperature inside the car, thus saving electricity for air conditioning. From 1997, Japan's automobile glass all added cerium oxide, cerium oxide used in automobile glass in 1996 at least 2000 tons, the United States about 1000 tons. 2, cerium is currently being applied to automobile exhaust purification catalysts, can effectively prevent a large number of automobile exhaust emissions into the air in the United States in this area of consumption accounted for the consumption of rare earths more than one-third of the total consumption of rare earths. 3, cerium sulphide can be used to replace lead, cadmium and other environmentally and humanly hazardous metals applied to Environment and human harmful metals such as lead, cadmium and other metals applied to pigments, can be coloring plastics, can also be used in coatings, inks and paper and other industries. The current leader is the French company Rh?ne-Poulenc.4 The Ce:LiSAF laser system is a solid-state laser developed by the United States, which can be used to detect biological weapons by monitoring the concentration of tryptophan, and can also be used in medicine. Cerium applications are very wide, almost all rare earth applications contain cerium. Such as polishing powder, hydrogen storage materials, thermoelectric materials, cerium tungsten electrodes, ceramic capacitors, piezoelectric ceramics, cerium silicon carbide abrasives, raw materials for fuel cells, gasoline catalysts, certain permanent magnetic materials, a variety of alloy steels and non-ferrous metals.
Praseodymium (Pr): 1, praseodymium is widely used in architectural ceramics and ceramics, and ceramic glaze mixed with color glaze, can also be used as a separate underglaze pigment, made of yellowish pigments, pure and elegant tone. 2, used in the manufacture of permanent magnets. Choose cheap praseodymium metal instead of pure neodymium metal to manufacture permanent magnet materials, its anti-oxidation properties and mechanical properties significantly improved, can be processed into a variety of shapes of magnets. It is widely used in all kinds of electronic devices and motors.3, Used in oil catalytic cracking. Praseodymium-neodymium enriched material is added into Y-type zeolite molecular sieve to prepare oil cracking catalyst, which can improve the activity, selectivity and stability of the catalyst. China began to put into industrial use in the 1970s, the dosage is increasing.4, praseodymium can also be used for abrasive polishing. In addition, praseodymium in the field of optical fiber use is also more and more extensive.
Needebodymium (Nd): The arrival of the element neodymium has enlivened the field of rare earths, playing an important role in the field of rare earths and shaping the rare earth market. The biggest user of neodymium metal is NdFeB permanent magnet material. The introduction of NdFeB permanent magnets has injected new vitality and vigor into the rare earth high-tech field. NdFeB magnets have a high magnetic energy product, known as the contemporary "king of permanent magnets", and are widely used in electronics, machinery and other industries with its excellent performance. The successful development of Alpha Magnetic Spectrometer marks that the magnetic properties of NdFeB magnets in China have crossed the world-class level. Neodymium is also used in non-ferrous metal materials. In magnesium or aluminum alloy with 1.5-2.5% neodymium, can improve the alloy's high temperature performance, airtightness and corrosion resistance, widely used as aerospace materials. In addition, neodymium-doped yttrium aluminum garnet produces short-wave laser beams, which are widely used in industry for welding and cutting of thin materials with a thickness of less than 10mm. In medicine, neodymium-doped yttrium aluminum garnet lasers are used instead of scalpels to remove surgical or sterilize trauma openings. Neodymium is also used in the coloring of glass and ceramic materials as well as additives for rubber products. With the development of science and technology, rare earth science and technology to expand and extend the field, neodymium element will have a broader utilization space.
Promethium (Pm): Promethium for the nuclear reactor production of man-made radioactive elements, the main uses are as follows: 1, can be used as a source of heat. It can be used as a heat source, to provide auxiliary energy for vacuum detection and artificial satellites. 2, Pm147 emits low-energy beta rays, which are used to manufacture promethium batteries. As a power source for missile guidance instruments and clocks. These batteries are small and can be used continuously for several years. In addition, promethium is used in portable X-ray instruments, in the preparation of phosphors, in thickness measurements, and in beacon lights.
Samarium (Sm): samarium cobalt magnets are the first industrial applications of rare earth magnets. This kind of permanent magnet has two types, SmCo5 system and Sm2Co17 system. smCo5 system was invented in the early 70's, and Sm2Co17 system was invented in the later period. Now it is the demand for the latter that is dominant. The purity of samarium oxide used in samarium cobalt magnets is not too high, and about 95% of the products are mainly used for cost consideration. Besides, samarium oxide is also used in ceramic capacitors and catalysts. In addition, samarium also has nuclear properties, and can be used as the structure material of the atomic energy reactor, screen material and control material, so that the nuclear fission produces huge energy can be utilized safely.
Europium(Eu):Europium oxide is mostly used in phosphor.Eu3+ is used as activator of red phosphor,Eu2+ is used in blue phosphor. Now Y2O2S:Eu3+ is the best phosphor for luminescence efficiency, coating stability and recycling cost. Together with the improvement of the technology to increase the luminous efficiency and contrast, it is being widely used. In recent years, europium oxide is also used as excited emission phosphor for new X-ray medical diagnostic system. Europium oxide can also be used in the manufacture of colored lenses and optical filters, for magnetic bubble storage devices, in the control materials of atomic reactors, screen materials and structural materials can also play a role.
Gadolinium (Gd): 1, its water-soluble paramagnetic complexes can medically enhance the human body's nuclear magnetic **** vibration (NMR) imaging signal. 2, its sulfur oxides can be used as a special brightness of the oscilloscope and x-ray fluorescent screen matrix grid. 3, gadolinium in gadolinium-gallium-garnet gadolinium for the memory of the magnetic bubble memory memory is ideal for a single substrate. 4, in the absence of the limitations of the Camot cycle, it can be used as a solid-state magnetic cooling medium. 5, used as a control material for atomic reactors and structural materials. cooling medium.5, Used as an inhibitor to control the chain reaction level in nuclear power plants to ensure the safety of nuclear reactions.6, Used as an additive in samarium cobalt magnets to ensure that the performance does not change with temperature. In addition, gadolinium oxide is used together with lanthanum to contribute to changes in the glass transition region and to improve the thermal stability of the glass. Gadolinium oxide is also used in the manufacture of capacitors, x-ray intensifying screens. In the world is currently working to develop gadolinium and its alloys in magnetic cooling applications, has made a breakthrough, room temperature using superconducting magnets, metal gadolinium or its alloys for cooling medium of the magnetic refrigerator has been introduced.
Terbium (Tb): 1, phosphor used for three-color phosphor in the green powder activator, such as terbium-activated phosphate matrix, terbium-activated silicate matrix, terbium-activated cerium-magnesium-aluminate matrix, in the excitation state are emitted in the green light. 2, magneto-optical storage materials, in recent years, terbium-based magneto-optical materials have reached a large scale of mass production, the development of magneto-optical discs using the amorphous film of Tb-Fe as a computer storage element, storage capacity has been increased. The magnetic optical disk developed by Tb-Fe amorphous film as a computer storage element can increase the storage capacity by 10 to 15 times.3, Magneto-optical glass, Faraday spinning glass containing terbium is a key material for manufacturing rotators, isolators and circulators which are widely used in laser technology. In particular, terbium dysprosium iron magnetostrictive alloy (TerFenol) development of the development of terbium is to open up new uses, when Terfenol placed in a magnetic field, the size of the change than the general change in the magnetic material large changes in this change can be made to achieve some of the precision mechanical movement. Terbium-Dysprosium began to be used primarily in sonar, but is now widely used in a variety of applications, from fuel injection systems, liquid valve control, and micropositioning to mechanical actuators, mechanisms, and the regulation of aircraft space telescopes, such as wing regulators.
Dysprosium (Dy): 1, used as an additive in neodymium-iron-boron (NdFeB) system of permanent magnets, adding about 2-3% dysprosium to such magnets can improve their coercivity, dysprosium was not in great demand in the past, but with the increase in the demand for NdFeB magnets, it has become a necessary additive element, and the grade must be around 95-99.9%, and the demand is also increasing rapidly. 2, dysprosium is used as a phosphor activator, and trivalent Dysprosium is a promising single light-emitting center of the activation ion of three-color luminescent materials, which is mainly composed of two emission bands, one for the yellow light emission, the other for the blue light emission, dysprosium-doped luminescent materials can be used as a three-color phosphor. 3, dysprosium is the preparation of large magnetostrictive alloy terbium dysprosium iron (Terfenol) alloy of the necessary metal raw materials that can make a number of mechanical movement of the precision of the activity can be realized. 4, dysprosium metal Dysprosium can be used as a magneto-optical storage material with high recording speed and reading sensitivity.5 It is used for the preparation of dysprosium lamps, and the working substance used in dysprosium lamps is dysprosium iodide, which has the advantages of high brightness, good color, high color temperature, small size, and stable arc and has been used as a source of illumination for movies and printing.6 Dysprosium has a large neutron capture cut-off area, and has been used to determine neutron energy spectra or as a neutron absorber in the atomic energy industry.7 Dysprosium is also used to make the neutron energy spectrum and the neutron absorber. Dysprosium is used in the atomic energy industry to determine neutron spectra or as a neutron absorber.7 Dy3Al5O12 can also be used as a magnetic working substance for magnetocooling. With the development of science and technology, dysprosium applications will continue to expand and extend.
Holmium (Ho): 1, used as an additive in metal halide lamps, metal halide lamps are a kind of gas discharge lamps, which are developed on the basis of high-pressure mercury lamps, and are characterized by the bulb being filled with a variety of different rare-earth halides. Currently, the main one used is rare earth iodide, which emits different spectral light colors during gas discharge. The working substance used in holmium lamps is holmium iodide, which allows for a higher concentration of metal atoms in the arc zone, thus greatly increasing radiation effectiveness.2 Holmium can be used as an additive to yttrium-iron or yttrium-aluminum garnet.3 Holmium-doped yttrium-aluminum garnet (Ho:YAG) emits a 2-μm laser, and human tissues have a high rate of absorption of 2-μm lasers, which is almost three orders of magnitude higher than that of Hd:YAG. Therefore, when medical procedures are performed with Ho:YAG lasers, not only can surgical efficiency and precision be improved, but also the area of thermal damage can be reduced to a smaller size. The free beam produced by Holmium crystal can eliminate fat without generating excessive heat, thus reducing thermal damage to healthy tissues, and it is reported that the treatment of glaucoma with Holmium laser in the U.S. reduces the pain of surgery for patients. The level of 2μm laser crystals in China has reached the international level, and we should vigorously develop and produce such laser crystals.4 In the magnetostrictive alloy Terfenol-D, a small amount of holmium can be added to reduce the external field required for the saturation magnetization of the alloy.5 In addition, holmium-doped optical fibers can be used to make fiber lasers, fiber optic amplifiers, fiber optic sensors, etc. Optical communication devices will play an even more important role in the rapid development of fiber optic communication today.
Holmium doped fiber can be used to make fiber laser, fiber amplifier, fiber sensor and other optical communication devices.
Erbium (Er): 1, Er3+ light emission at 1550nm has a special significance, because the wavelength is located in the optical fiber communication of the lowest loss of optical fiber, erbium ions (Er3+) by the wavelength of 980nm, 1480nm light excitation, from the ground state of 4I15/2 jumped to the high-energy state of 4I13/2, when in the high-energy state of the Er3+ and then jump back to the ground state emits 1500 nm. Back to the ground state when the emission of 1550nm wavelength light, quartz optical fiber can transmit a variety of different wavelengths of light, but different light attenuation rate is different, 1550nm band of light in the quartz optical fiber in the transmission of the time attenuation rate is the lowest (0.15 dB/km), almost the lower limit of the limiting attenuation rate. Therefore, fiber optic communication at 1550nm for signal light, the minimum optical loss. Thus, if the appropriate concentration of erbium doped into a suitable matrix, can be based on the role of the laser principle, the amplifier is able to compensate for the loss in the communication system, so in the need to amplify the wavelength of 1550nm optical signals in the telecommunication network, erbium-doped fiber optic amplifier is essential optical devices, erbium-doped silica fiber amplifiers have been commercialized. It is reported that in order to avoid useless absorption, the amount of erbium doping in optical fibers is tens to hundreds of ppm. the rapid development of fiber optic communications will open up new fields of erbium applications.2 In addition, erbium-doped laser crystals and their output of 1730 nm laser light and 1550 nm laser light are safe for the human eye, with better atmospheric transmission performance, stronger penetration of the battlefield smoke, good secrecy, less likely to be detected by the enemy, and irradiation of The contrast of the military target is larger, has been made for military use on the human eye safety portable laser rangefinder.3, Er3+ added to the glass can be made of rare earth glass laser material, is currently the output pulse energy is the largest, the output power of the highest solid-state laser material.4, Er3+ can also be made of rare earth on the conversion of the laser material of the activation of the ions.5, in addition to the erbium can also be applied to spectacle lenses glass, crystalline glass decolorization and coloring, etc.
Thulium (Tm): 1, thulium is used as a medical lightweight X-ray machine ray source, thulium irradiated in a nuclear reactor produces an isotope that can emit X-rays, which can be used to manufacture portable blood irradiator, this radiometer can make thulium-169 by the high school beam of neutrons to the role of the transformation of thulium-170, X-rays irradiation of the blood and make the decline in leukocytes, which is the cause of white blood cells, organ transplant rejection reaction, and thus the white blood cells. The thulium element can also be used in clinical diagnosis and treatment of tumors because it has a high affinity for tumor tissues, and heavy rare earths have a greater affinity than light rare earths, especially thulium, which has the greatest affinity.3 Thulium is used in the phosphor for X-ray sensitizing screens as an activator, LaOBr:Br (blue), which enhances the sensitivity of optics, and thus reduces X-rays to humans. Therefore, it reduces the exposure and harm of X-rays to human beings, and can reduce the X-ray dose by 50% compared with the previous calcium tungstate sensing screen, which is of great practical significance in medical applications.4 Thulium can also be used as an additive in the new type of illumination source, metal halide lamps.5 Tm3+ can be added to the glass to make the rare-earth glass laser material, which is the solid-state laser material with the largest output pulse volume and the highest output power at present. Tm3+ can also do rare earth upconversion laser material activation ion.
Ytterbium (Yb): 1, for heat shielding coating materials. Ytterbium can significantly improve the corrosion resistance of electrodeposited zinc layer, and ytterbium-containing plating than ytterbium-containing plating grains are small, uniform and dense. 2, as magnetostrictive materials. This material has a super magnetostrictive that is in the magnetic field expansion properties. The alloy is mainly composed of ytterbium / ferrite alloy and dysprosium / ferrite alloy, and add a certain proportion of manganese, in order to produce a super magnetostrictive.3, ytterbium components for the determination of pressure, the test proved that ytterbium components in the calibrated pressure range of sensitivity, at the same time, for the ytterbium in the determination of the application of the pressure to open up a new way. , 4, molar cavity resin-based fillings to replace the past widespread use of silver amalgam. 5, Japanese scholars have successfully completed the preparation of ytterbium doped gadolinium gallium garnet buried line waveguide lasers, the completion of this work on the further development of laser technology is very meaningful. In addition, ytterbium is also used in phosphor activator, radio ceramics, electronic computer memory components (magnetic bubble) additives, and glass fiber flux and optical glass additives.
Lutetium (Lu): 1, the manufacture of certain special alloys. For example, lutetium aluminum alloy can be used for neutron activation analysis.2, Stabilized lutetium nuclides play a catalytic role in petroleum cracking, alkylation, hydrogenation, and polymerization reactions.3, An additive element of yttrium-iron or yttrium-aluminum garnet, to improve certain properties.4, Raw material for magnetic bubble storage.5, A composite functional crystal doped with lutetium tetraborate aluminum yttrium neodymium belongs to the technological field of crystal growth by cooling in a saline solution, and it is proved by experiments that the doped lutetium NYAB crystals are superior to NYAB crystals in terms of optical homogeneity and laser properties.6, Lutetium has been found to have potential uses in electrochromic displays and low-dimensional molecular semiconductors by foreign authorities. In addition, lutetium is used in energy battery technology and as an activator for phosphors.
Yttrium (Y): 1, steel and non-ferrous alloy additives. FeCr alloys usually contain 0.5-4% yttrium, yttrium can enhance the oxidation resistance and ductility of these stainless steels; MB26 alloy after adding an appropriate amount of yttrium-rich mixed rare earths, the alloy's comprehensive performance has been significantly improved, and can be used to replace part of the medium-strength aluminum alloys used in the aircraft's stress components; in Al-Zr alloys, adding a small amount of yttrium-rich rare earths, the comprehensive performance of the alloy has been improved, and can replace some of the medium-strength aluminum alloys used for aircraft's stress components. Add a small amount of yttrium-rich rare earths in Al-Zr alloy, can improve the conductivity of the alloy; the alloy has been adopted by most of the domestic wire factory; in the copper alloys to add yttrium, improve the electrical conductivity and mechanical strength. 2, containing yttrium 6% and aluminum 2% of silicon nitride ceramic materials, can be used to develop engine components. 3, with a power of 400 watts of neodymium yttrium aluminum garnet laser beam for large components such as drilling, cutting, and welding and other machining. 4, by Y Al garnet single crystal sheet composed of electron microscope fluorescent screen, high fluorescence brightness, low absorption of scattered light, resistance to high temperature and good resistance to mechanical abrasion.5, yttrium-containing up to 90% of the high yttrium structural alloys, can be applied to aviation and other requirements of low density and high melting point of the occasions.6, yttrium-doped SrZrO3 high-temperature proton conductive materials, which is currently attracting attention, the fuel cell, electrolysis cell and the requirement of high hydrogen solubility gas-sensitive components. solubility for the production of gas-sensitive components. In addition, yttrium is also used as a high-temperature resistant spray material, a diluent for atomic energy reactor fuel, an additive for permanent magnet materials, and as an absorbent in the electronics industry.
Scandium (Sc): 1, in the metallurgical industry, scandium is commonly used in the manufacture of alloys (additives to alloys) to improve the alloy's strength, hardness, and heat resistance and performance. For example, adding a small amount of scandium in iron water can significantly improve the performance of cast iron, and a small amount of scandium added to aluminum can improve its strength and heat resistance. 2, in the electronics industry, scandium can be used as a variety of semiconductor devices, such as scandium sulfite in the semiconductor application has attracted attention at home and abroad, containing scandium ferrite in the core of the computer is also quite promising. 3, in the chemical industry, scandium compounds used as alcohol dehydrogenation and In the chemical industry, scandium compounds are used as efficient catalysts for the dehydrogenation and dehydration of alcohol, the production of ethylene, and the production of chlorine from waste hydrochloric acid.4 In the glass industry, scandium-containing special glass can be manufactured.5 In the electric light industry, scandium-containing sodium lamps are made of scandium and sodium, which have the advantages of high efficiency and positive light color.6 Scandium exists in the natural world in the form of 45Sc, and there are also nine radioisotopes of scandium, i.e., 40 to 44Sc and 46 to 49Sc. Among them, 46Sc has been used as a tracer in chemical industry, metallurgy and oceanography, etc.7 In medicine, there are also researches on the use of 46Sc to cure cancer.
Information, biology, new materials, new energy, space and the ocean by contemporary scientists pushed for the six new science and technology groups, the reason why people attach importance to rare earth, rare earth research, development of rare earth, rare earth elements in the six science and technology groups have its own show of skill in the world. However, the rare earth elements are still a group of elements that are not yet fully recognized by people, which requires a great deal of effort to research, recognize them, so as to hold them, so that they have a greater contribution to mankind, the rare earth elements will be in the development of high-tech vitality.