The most important thing is the weapon system? Electronic? Night vision device? A lot. For example, if there is no rare earth component in the high-end weapon system, it's just like cooking without salt or seasoning. No matter how good the dish is, it doesn't taste good without salt and seasoning. The following is a reference. Rare is rare in English. Earth, which means "rare soil". In fact, this is just a misunderstanding left over from the 2118 century. After 1787, several rare earth elements were discovered one after another, but few corresponding minerals were found. Due to the limitation of science and technology at that time, people could only make some impure oxides like soil, so people left such a unique and interesting name for this group of elements.

according to the definition of rare earth elements by the international union of pure and applied chemistry, rare earth elements are 15 lanthanides with atomic numbers from 57 to 71 in the third subgroup of Mendeleev's periodic table, namely lanthanum (57), cerium (58), praseodymium (59), neodymium (61), promethium (61) and samarium. Except scandium and promethium, the other 15 elements are often generated.

according to some differences in physical and chemical properties and geochemical properties between rare earth elements and the requirements of separation process, scholars often divide rare earth elements into light and heavy groups or light, medium and heavy groups. The division of the two groups is based on gadolinium. Seven elements before gadolinium, namely lanthanum, dysprosium, cerium, praseodymium, neodymium, promethium, samarium and europium, are light rare earth elements, also known as cerium group rare earth elements. Gadolinium and nine elements after gadolinium, such as terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium, are called heavy rare earth elements, also known as yttrium group rare earth elements. Although the atomic weight of yttrium is only 89, its chemical properties are closer to those of heavy rare earth elements because its ion radius is among the ion radius links of other heavy rare earth elements. In nature, it also occurs with other heavy rare earth elements. Therefore, it is classified as heavy rare earth group. There are no certain rules for the classification of light, medium and heavy rare earths. For example, according to the solubility of rare earth sulfate double salt, it can be divided into: insoluble cerium group is light rare earth group, including lanthanum, cerium, praseodymium, neodymium and samarium; The sparingly soluble terbium group is the medium rare earth group, including europium, gadolinium, terbium and dysprosium; The more soluble yttrium group is the heavy rare earth group, including yttrium, holmium, erbium, thulium, ytterbium and lutetium. However, the solubility difference between adjacent elements in each group is very small, so it is not clear by this method. At present, the extraction method is often used for grouping. For example, with bis (2) ethylhexyl (phosphoric acid), P214 can be grouped between neodymium and samarium, and then between gadolinium and terbium. Lanthanum, cerium, praseodymium and neodymium are called light rare earths, samarium, europium and gadolinium are called medium rare earths, and terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium plus yttrium are called heavy rare earths.

the content of rare earth in the earth's crust is not rare, and the Clark value of this group of elements is 1.1236%, including 1.11592% for cerium group and 1.1177% for yttrium group. It is more than common elements such as copper (1.11%), zinc (1.115%), tin (1.114%), lead (1.1116%), nickel (1.118%) and cobalt (1.113%). This group of elements is not soil, but a group of typical metal elements, and its activity is second only to alkali metals and alkaline earth metals.

table 1-1? The abundance of rare earth elements in the crust is

yuan? Su? Name? Said

sc

y

la

ce

pr

nd

pm

sm

crustal abundance, ppm

25

31

35

66

9.1 < Su? Name? Said

eu

GD

TB

dy

ho

er

TM

Yb

Lu

crustal abundance, ppm

2.1

6.1

1.2

4.5. Lanthanum is very similar to the next 14 elements, so chemists can only put them in a lattice. No wonder some people treat them as "isotopes", but because of their different atomic numbers, they can't be counted as real isotopes. That is to say, their properties are very similar, but they are not exactly the same, which makes it difficult to separate this group of elements, but it also shows that separation is possible as long as their slight differences are used; On the other hand, their electronic structure has an internal electron shell that is not completely filled, that is, the 4f electron shell. Because of the different electron numbers of 4f layers, each element in this group has a very special personality, especially optical and magnetic properties, just like a piano with a complete keyboard and a wide range.

Information, biology, new materials, new energy, space and ocean have been pushed into six new science and technology groups by contemporary scientists. The reason why people attach importance to rare earth, study rare earth and develop rare earth is that rare earth elements have a place to display their skills in these six science and technology groups. However, after all, rare earth elements are still a group of elements that people have not fully understood, which requires great efforts to study and understand them, so as to support them and make them make greater contributions to mankind. < P > Rare earth is not a certain mineral, but a kind of rare mineral. There are 17 kinds of rare earth elements, which are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and lutetium. As early as 1787, chemists discovered several rare earth elements one after another, but few corresponding minerals were found, so chemists called these substances rare earth. Of course, the rarity of rare earth elements is relative. The geological survey results in recent years show that rare earth elements are quite abundant in the earth's crust, for example, cerium is higher than cobalt, yttrium is higher than lead, and lutetium and thulium are equivalent to antimony, mercury and silver.

However, because rare earth elements usually occur in the earth's crust, and their physical and chemical properties are close, it is very difficult to separate these rare earth elements. Therefore, the purification of rare earth elements is a huge difficulty in chemical research. Yttrium was isolated by Finn Gadolin in 1794, and promethium was made by American Malinschi and others in 1947. The complete purification of 17 kinds of rare earth elements has gone through more than 151 years. Academician Xu Guangxian's important contribution is also in the field of rare earth extraction. He put forward the theory of cascade extraction, which raised the extraction and separation technology of rare earth in China to the international advanced level.

China's rare earth resources rank first in the world

China is rich in rare earth mineral resources with superior metallogenic conditions, and its proven reserves rank first in the world, which provides a solid foundation for the development of China's rare earth industry. There are about 251 kinds of rare earth minerals found in the world, but only 51 ~ 61 kinds of rare earth minerals have industrial value, and only about 11 kinds of rare earth minerals have mining value at present. Besides China, the countries with rare earth resources in the world include the United States, Russian, Canadian and Australian.

China's rare earth resources account for 41.36% of the world, and its distribution is extremely reasonable. It is a veritable country with rare earth resources. The main rare earth mines in China are Baiyun Obo Rare Earth Mine, Shandong Weishan Rare Earth Mine, Mianning Rare Earth Mine, Jiangxi Weathered Crust Leaching Rare Earth Mine, fergusonite in Hunan Province and coastal placer mines along the long coastline, etc. At present, the high-purity rare earth produced in China accounts for more than 81% of the world's output.

Rare earths are widely used in life

We deal with rare earth materials every day, because computers and televisions we often use contain rare earth materials. Because rare earth elements have a special electronic shell structure, they can convert the absorbed energy into light and emit it, so rare earth elements can be used to manufacture phosphors in electrical picture tubes. CRT phosphor contains rare earth elements yttrium and europium, and the use effect of this phosphor is far better than that of non-rare earth sulfide red phosphor used before. At present, various rare earth phosphors are widely used, such as radar picture tubes, fluorescent lamps and high-pressure mercury lamps.

rare earth oxides can also be used to make special glass. For example, the glass containing rare earth element lanthanum is a kind of glass with excellent optical properties, which has high refractive index, low dispersion and good chemical stability, and can be used to manufacture the lens of advanced cameras and periscope. Rare-earth oxides can also be used to make colored glass. Adding rare-earth element Nd can make the glass wine red, adding rare-earth element Pr can make the glass green, and adding rare-earth element Er can make the glass pink. These stained glasses are unpredictable in color and can be used to make decorations.

Rare earth elements can also play an important role in protecting our health. Rare earth compounds can be used to stop bleeding, and the hemostasis effect is rapid and can last for about one day. The use of rare earth drugs has a good effect on dermatitis, allergic dermatitis, gingivitis, rhinitis and phlebitis. For example, the use of rare earth drugs containing cerium salts can reduce the inflammation of burn wounds and accelerate healing. The anticancer effect of rare earth elements has aroused widespread concern. Rare earth elements can not only eliminate harmful free radicals in the body, but also reduce the level of calmodulin in cancer cells and increase the level of tumor suppressor genes.

in addition to the above three uses, rare earth elements are widely used in our lives. As long as the right amount of rare earth elements are added to some traditional products, some magical effects will be produced. At present, rare earths have been widely used in dozens of industries such as metallurgy, petroleum, chemical industry, textile, medicine and agriculture. For example, rare earth steel can significantly improve the wear resistance, corrosion resistance and toughness of steel; Rare earth aluminum wire rod can improve the strength and conductivity while reducing the fineness of aluminum wire; Spraying rare earth pesticides on fruit trees can not only eliminate pests and diseases, but also improve the fruit hanging rate; Rare earth compound fertilizer can not only improve soil structure, but also increase the output of agricultural products; Rare-earth petroleum cracking catalyst used in China's oil refining industry costs less than 1 billion yuan, but it can improve the output efficiency of light oil such as gasoline many times.

besides, as you may know, it is liquid crystal and warheads, and China has the largest reserves. ?

In fact, the United States and * * didn't tell everyone their real purpose: emerging energy! ?

rare earth and energy are out of the question? If you don't believe me, just watch what I say. ?

I guess: the rare metal alloy material of rare earth is an undeformed superhard material with high temperature and high pressure resistance, and it is an important raw material for manufacturing semi-solid energy engine cylinder blocks and accessories. This is the secret of the United States. They call this kind of engine "detonation engine", which is the top secret technology in the United States. Everyone envies the high speed of flying saucers, which is the guarantee of instantaneous high power. When the plane is caught up by the missile, it can start the thin jet engine to accelerate out of the missile's killing range. In the ultra-high altitude and oxygen-deficient environment, it is a near-earth application technology of near-space technology, an oxygen-free non-rocket flight technology, and rare earth is the key raw material of this technology. ?

The coexistence of rare earths is vividly reflected. Some rare element alloys in rare earths are accompanied by sensitive and fickle things, which are more sensitive to temperature than imagined. A slight temperature difference can change their physical and chemical properties. This is the discovery of * *. Now, some temperature difference technologies have been made public, but the actual core temperature difference technology has not been mentioned at all, that is, the temperature difference generator technology: 1. Liquid technology, that is, 2. Solidify this technology and combine it with temperature memory technology to generate deformation and power by using temperature difference. Make the generator work to generate electricity or run the engine. So as long as the sun rises and falls, * * will never lack power energy, not perpetual motion machine or nuclear fission, but a real future new energy technology. Unfortunately, only China has a large number of this raw material, which is also called "earth". So I can't tell you the real use of rare earths. In fact, its strategic value is no less than that of nuclear mines! ?

China has natural resources but wastes them. Without the waste of human resources, there will be no waste of technical resources, and there will be no waste of resources left by ancestors! ?

"There is oil in the Middle East and rare earth in China." This is the "famous saying" when **1992 southern tour arrived in Jiangxi. However, from 1991 to 2115, the export volume of rare earths in China increased by nearly 11 times, but the average price was reduced to 61%. ? In 2111, the country drastically reduced the export of rare earths < P > The following are the military uses of rare earths: Why can Patriot missiles shoot down Scud more easily? Why is it that American M1 and Soviet T-72 tanks can always fire earlier and hit more accurately, although there is not much difference in the direct distance between their main guns? Why can F-22 fighters cruise at supersonic speed? ......

These "why" outline the great progress of today's military science and technology, and at the same time outline the turmoil and conflicts in the world in the past 21 years. For each "why", there is a specific and clear answer. However, from the perspective of materials science, "rare earth" can solve all the above problems at one time.

the development and application of rare earths have provided powerful engines for military science and technology in recent decades.

The incredible military miracles in the Gulf War, and the asymmetric control ability of the US military in the local war after the Cold War, in a sense, are all made by rare earths.

because of this, the development and utilization of rare earth also breeds great danger. On the one hand, more and more countries and military forces participate in the competition and research and development of rare earths in order to gain asymmetric control over their opponents, which breeds the risk of an arms race; On the other hand, countries that have acquired this capability are more inclined to settle disputes by threats or wars. In this regard, China, as a country with the largest rare earth reserves in the world, it is necessary to cool this arms race from the source, strictly limit the exploitation of rare earths and immediately ban the export of rare earths.

in fact, the China government has paid little attention to the development of rare earths. As early as 1951s, Premier Zhou Enlai included rare earth development in China's first scientific and technological development plan. In 1975, a leading group for rare earths was established in China. Even though the State Council's institutions were adjusted a little, the specialized management organization for rare earths industry has been kept. In 1991, rare earths were listed as national protected minerals. From the policy aspect of rare earth protection, even China Petroleum has no such treatment, with specialized institutions, stable industrial policies and consistent overall control by the state. However, the achievements of the rare earth industry in decades of development basically remain at a low level of selling resources. Since 1999, the Ministry of Land and Resources has carried out numerous clean-up work on the status quo of rare earth production, aiming at problems such as indiscriminate digging and mining, overcapacity and disorder. The measures taken include total control, blowing up illegal mines, confiscation of production equipment, judicial intervention, licensing, signing letters of responsibility with grass-roots governments and signing contracts with mines ... In 2115, the Ministry of Commerce began to control rare earth exports with taxes. These measures are strong and last for a long time, almost reaching the power limit of the management department.

however, the chaos remains. Someone once summed up that there are seven mysteries about rare earths in China: 1. Macro-control oriented by industrial policy has always been difficult to work; 2. Adjust the industrial structure and control students.