1. Bird tungsten industry.
2. New materials.
3.*ST Xiangdian.
4. Yongding shares.
Rare earth is a general term for scandium, yttrium and lanthanide *** 17 in the third subgroup of the periodic table of elements. It generally exists in the form of oxides and belongs to non-renewable resources. Rare earth is not rare, but turning it into a useful material is complicated, cumbersome and costly, hence the name "rare earth". These 17 elements can usually be divided into light rare earth and heavy rare earth, of which heavy rare earth is more valuable.
Extended data
Rare earth carbonate chloride
These are the two most important primary products in the rare earth industry. Generally speaking, there are two main processes to produce these two products.
One process is concentrated sulfuric acid roasting process, that is, rare earth concentrate and sulfuric acid are mixed and roasted in a rotary kiln. After the roasted ore is leached with water, soluble rare earth sulfate enters the aqueous solution, which is called leaching solution. Then ammonium bicarbonate is added into the leaching solution to precipitate the rare earth in the form of carbonate, and the rare earth carbonate is obtained after filtration.
Another process is called caustic soda process, which is called alkali process for short. Generally, 60% of rare earth concentrate is mixed with concentrated alkali liquor, which is melted and reacted at high temperature to decompose the rare earth concentrate and turn the rare earth into rare earth hydroxide. The alkali cake was washed with water to remove sodium salt and excess alkali, then the washed rare earth hydroxide was dissolved in hydrochloric acid, and the rare earth was dissolved in rare earth chloride solution, and the acidity was adjusted to remove impurities. Concentrate and crystallize the filtered rare earth chloride solution to obtain solid rare earth chloride.
Rare earth phosphate rock
In addition to all kinds of rare earth minerals, a considerable part of rare earth elements in nature coexist with apatite and phosphorite minerals. Because the ion radius of rare earth (0. 848 ~ 0. 106 nm) is very close to Ca2+(0. 106 nm), rare earth exists in phosphate rock in the form of isomorphism. The total reserves of phosphate rock in the world are about 1000 billion tons, and the average content of rare earth is 0. It is estimated that the total amount of rare earth associated with phosphate rock in the world is 50 million tons.