What Is Rare Earth?
Rare Earth is a general term for 17 elements of lanthanides and lanthanum and cerium in the chemical periodic table. There are 250 rare earth minerals in nature. The first to discover rare earths was the Finnish chemist John Gadolin. In 1794, the first rare earth "element" (alumina, Y2O3) was separated from a bituminous ore-like ore. Because rare earth minerals were found in the 18th century, only a small amount of water-insoluble water could be produced by chemical methods. Oxide, historically used to call this oxide "earth", hence the name rare earth.
The first is the lack of sulfides and sulfates (only very few), which indicates that the rare earth elements have oxophilic properties;
Second, the silicate of rare earth is mainly island-shaped, without layered, frame-like and chain-like structures;
Third, some rare earth minerals (especially complex oxides and silicates) are in an amorphous state;
The fourth is the distribution of rare earth minerals, mainly composed of silicates and oxides in magmatic rocks and pegmatites, and fluorine-carbonates and phosphates in hydrothermal deposits and weathering crust deposits. Most of the rich minerals are found in granite rocks and their associated pegmatite, gas-forming hydrothermal deposits and hydrothermal deposits;
Fifth, rare earth elements are often symbiotic in the same mineral due to their close atomic structure, chemical and crystal chemical properties. That is, the rare earth elements of the lanthanum and the lanthanum are often present in one mineral, but these elements do not coexist in equal amounts. Minerals are mainly composed of lanthanum-containing rare earths, and some minerals are mainly 钇.
Among the more than 250 kinds of rare earth minerals and rare earth-containing minerals that have been discovered, there are only 10 kinds of industrial minerals suitable for the current conditions of metallurgy: