Rare earth elements

Rare earth elements serve as a strategic resource for non-renewable scarcity. It is known as "industrial vitamins" and "mother of new materials." It is widely used in cutting-edge technology and military fields. In the steel making process, only a small amount of rare earth is added to the steel. It will make the original high-quality steel more high quality and improve its service life. In the military field, rare earth can greatly improve the alloy tactical performance of weapons and equipment. For example, in the Gulf War, the night vision device with the addition of rare earth elements lanthanum became a source of overwhelming advantage for US tanks. In the field of nuclear energy, rare earth elements gadolinium and its isotopes are the most effective neutron absorbers. It can be used as an inhibitor to control the chain reaction of nuclear power plants. Become the patron saint of nuclear reactors. In reality, whether it is a tiny mobile phone screen, a digital camera, or a huge missile, radar, submarine, rare earth is everywhere.

People often refer to solid oxides that are insoluble in water and call them earth. In fact, rare earth are a general term for 17 metal elements such as lanthanum, cerium and lanthanum. Because it was difficult to smelt and purify at the time, the minerals used to extract such elements were rare. Moreover, the obtained oxide is difficult to melt, is also difficult to dissolve in water, is difficult to separate, and looks like "earth", and is called rare earth. This name has been in use since the 18th century. The rare earth has a fraction of light rare earth and medium heavy rare earth. The lanthanum(La), cerium(Ce), praseodymium(Pr), neodymium(Nd), promethium(Pm), samarium(Sm) and europium(Eu) are light rare earth elements, also known as lanthanum group rare earth element. The scandium(Sc), gadolinium(Gd), terbium(Tb), dysprosium(Dy), holmium((Ho), erbium(Er), thulium(Tm), ytterbium(Yb), lanthanum(Lu) and yttrium(Y) are medium and heavy rare earth elements, also known as lanthanum group rare earth elements. The atomic electronic layer structure and physicochemical properties of the elements and their symbiosis and ionic radius in minerals are different. In application, light rare earth is also called “fake rare earth” by people in the industry. Although it has a large stock and wide application, its value is relatively low. The heavy rare earth resources are scarce and can be used in high-tech fields such as aerospace, military, national defense and new material synthesis. They are expensive and have little substitutability.

According to experts, rare earth elements are widely distributed in the earth's crust, but they are very uneven. Among the countries with more rare earth reserves are China, India, the United States, Canada, Russia, Australia, South Africa, Egypt, etc. Chinese rare earth minerals are rich, and the world is the first in four worlds. The first in resource reserves, accounting for about 23%; the first in production, accounting for 80% to 90% of the world's rare earth commodities; the first in sales, 60% to 70% of rare earth products are exported abroad and the first in an application, most of the rare earth are used domestically. Not only that, there are more than 70% of the world's heavy-earth resources in the ion-type mines in southern China. Mainly distributed in Jiangxi, Guangdong, Fujian, Guangxi and other provinces. Its heavy rare earth is as high as 30%-80%. It is a strategic resource with an absolute competitive advantage. China is still the only country in the world that can supply all rare earth elements. In China, the earliest rare earth mine was discovered in 1934, and the founder was Professor He Zuolin. After that, Chinese geoscience scientists constantly explored and summarized the characteristics of Chinese geological structure evolution and development. Using and creating new mineralization theories, a number of important rare earth deposits have been discovered and identified nationwide. It also summarizes that China's rare earth resources have the most basic characteristics such as good metallogenic conditions, wide distribution, light north and heavy south, high content of valuable elements and large comprehensive utilization value. There are 15 elements in the rare earth element derived from a large "family" - lanthanides, which are the collective name for the elements from the 57th element to the 71 elements of the periodic table.

In terms of physical properties, the lanthanide metal is silvery white, soft and malleable. It is more active, second only to alkali metals and alkaline earth metals, and needs to be isolated from air. At the same time, the lanthanide metal is a strong reducing agent, and its reducing ability is second only to metallic magnesium (Mg), and its reactivity can be compared with aluminum. As the atomic number increases, the reducing power tends to gradually decrease. The electrons are gradually arranged in the inner 4f orbital, and the outer electrons are basically the same, so the chemical properties of these elements are similar.

Since the properties of various rare earth elements are extremely similar, they are often present in various complex minerals in the form of oxide mixtures. Therefore, the separation and purification of rare earth elements is an extremely difficult task. Until 1947, American scientists invented the separation of rare earth by ion exchange. And the famous scholar Spedding improved the ion exchange process to prepare a pure single rare earth of kilograms. Basic conditions have been created to study the intrinsic properties of various single rare earth and the use of rare earth. People gradually understand the rich properties of light, electricity, magnetism and nuclear species. It laid the foundation for the development and application of various rare earth functional new materials and new devices. Information, biology, new materials, new energy, space and oceans have been promoted by the contemporary scientists as six new technology groups. The reason why people pay attention to rare earth, research rare earth, and develop rare earth is because each element of rare earth has its own characteristics and has its own functions in the field of high-precision technology. At present, rare earth permanent magnets, luminescence, hydrogen storage, catalysis and other functional materials produced by rare earth elements are indispensable raw materials for high-tech industries such as advanced equipment manufacturing and new energy. Also widely used in electronics, petrochemical, metallurgy, machinery, new energy, light industry, environmental protection, agriculture and so on.