As a non renewable scarce strategic resource, it is called "industrial vitamin" and "mother of new materials". It is widely used in the fields of cutting-edge science and technology and military industry.
In the process of steelmaking, only a small amount of rare earth is added to the steel, which can make the original high-quality steel more "strong" and improve its service life.
In the military field, rare earth can greatly improve the alloy tactical performance of weapon equipment. For example, in the Gulf War, the night vision instrument with rare earth element lanthanum has become the overwhelming source of the U.S. tank.
In the field of nuclear energy, gadolinium and its isotopes are the most effective neutron absorbers, which can be used as chain reaction level inhibitors for nuclear power plants and become the "God of safety" for nuclear reactors
In reality, rare earths are everywhere, from mobile screens and digital cameras to missiles, radars and submarines. As a non renewable scarce strategic resource, it is called "industrial vitamin" and "mother of new materials". It is widely used in the fields of cutting-edge science and technology and military industry. So, how are rare earths discovered? How to start the journey of new use discovery? The reporter interviewed experts on rare earth separation technology on these issues.
People often call the solid oxide insoluble in water as earth, for example, alumina as "clay", calcium oxide as "alkaline earth", etc. In fact, rare earth is the general term of 17 metal elements such as lanthanum, scandium and yttrium. Because it was difficult to smelt and purify at that time, the minerals used to extract such elements were relatively rare, and the oxides obtained were difficult to melt, dissolve in water and separate, and the appearance was similar to "soil", which was called rare earth. This name has been used since the 18th century
The "big family" of rare earth includes light rare earth and medium heavy rare earth. Lanthanum, cerium, praseodymium, neodymium, promethium, samarium and europium are light rare earth elements, also known as cerium group rare earth elements; scandium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium are medium heavy rare earth elements, also known as yttrium group rare earth elements. Both of them have different atomic electronic layer structure, physical and chemical properties, as well as their symbiosis in minerals and ion radius.
In terms of application, light rare earth is also called "fake rare earth" by the insiders. Although it has a large stock and wide application, its value is relatively low. However, heavy rare earth resources are scarce and can be used in high-tech fields such as aerospace, military, national defense and new material synthesis, with high price and little substitutability.
According to the above experts, rare earth elements are widely distributed in the earth's crust, but they are very uneven. Among them, there are many rare earth reserves, including China and India in Asia, the United States and Canada in North America, Russia, Australia, South Africa, Egypt and other countries. China is rich in rare earth mineral resources, ranking the first in the four world: the first in resource reserves, accounting for about 23%; the first in production, accounting for 80-90% of the world's rare earth commodity volume; the first in sales, 60-70% of the rare earth products are exported to foreign countries; the first in application, most of the rare earth is used at home.
Not only that, more than 70% of the world's heavy rare earth resources are located in ion-based mines in southern China, mainly in Jiangxi, Guangdong, Fujian, Guangxi and other provinces, with heavy rare earth as high as 30% - 80%, which is a strategic resource with absolute competitive advantage. At present, China is the only country in the world that can supply all rare earth elements.
Full of historical misunderstanding, "twin brother" is regarded as "one person"
Rare earth elements were discovered in 1794 by gadolin, a Finnish chemist, from unknown minerals, namely "yttrium earth" (yttrium oxide) found in the beryllium yttrium ore. From the discovery of yttrium earth in 1794 to the extraction of the last rare earth element, promethium, in 1947, a total of 150 years have passed, during which there are many historical misunderstandings.
In fact, the discovery of rare earth elements was described as follows: the discovery of rare earth began in northern Europe. In 1787, amateur mineralogist Arrhenius found a black ore he had never seen in a small village near Stockholm called yteerby, and named it yteerite with the name of the village. In 1794 gadolin claimed to have discovered a new element "ytelium" from the mineral, and named it ytelium (yttrium).
People regard this year as the time when the first rare earth element "yttrium" was discovered. In fact, this is a misunderstanding. Because the "yttrium earth" discovered by gadolin is not a rare earth element, but only a mixed oxide of "yttrium group rare earth". Later scientists discovered heavy rare earth elements such as ytterbium, erbium and terbium from this "yttrium earth". It turns out that the original chemists regarded these "twin brothers" as "one person". The same misunderstanding happened to LREE.
In China, the earliest rare earth ore was discovered in 1934 by Professor He zuolin. After that, Chinese geologists continue to explore and summarize the characteristics of the evolution and development of China's geological structure, apply and create new metallogenic theories, find and explore a number of important rare earth deposits nationwide, and conclude that China's rare earth resources have the most basic characteristics of good metallogenic conditions, wide distribution, North light South heavy, high content of valuable elements, and great comprehensive utilization value Point.
There are 15 "members" of rare earth elements from a large "family" - lanthanide elements. They are the general names of 15 elements from element 57 to element 71 lutetium in the periodic table of elements.
In physical properties, lanthanide metals are silvery white, soft and malleable. It has strong activity, next to alkali metal and alkaline earth metal, and needs to be kept away from air. At the same time, lanthanide metal is a strong reducing agent, its reducing ability is second only to magnesium (mg), and its reactivity can be compared with aluminum. With the increase of atomic number, the reduction ability is gradually weakened, and the electrons are arranged in the 4f orbit in the inner layer and the electrons in the outer layer
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