General description of rare earth

General description of rare earth

Rare Earth Oxides

RE oxide are most stable from various RE compounds, the fundamental raw material of other compounds and are basic products of raw material in RE industry. RE oxides are generally prepared by ignition of corresponding hydroxide, oxalate, carbonate salt, nitrate salt, soleplate salt in the air. RE oxide are insoluble in water and basic solution, soluble in strong mineral acids, and apt to absorb cabin dioxide from air to form carbonate salt. All RE oxide are powder and their melt points are above 2300℃.

Rare earth hydroxides

RE Hydroxides are generally prepared by mixing corresponding soluble salt with ammonium hydroxide or sodium hydroxide they are soluble in acids, insoluble in water, and generally powder.

Rare earth Chlorides

There are two kinds of RE chlorides, anhydrous and hydrous chlorides. The former is prepared by heating, dewater in vacuum of it’s hydrous. The Later is prepared by condensing of its corresponding RE chloride solution. All RE chlorides are hydroscopic and substantially soluble in water.

Rare earth Sulphates

RE sulphates are generally prepared by adding sulphuric acid to their corresponding oxides, hydroxides, carbonates, and the solid state of the salt can be prepared by condensation of the solution. All RE sulphates are soluble in water, but their solubilities are lower and down with the temperature up.

Rare earth Carbonate

The solid RE carbonate can be prepared by adding more the solution of soluble RE salt. RE carbonates are little soluble in water, soluble in acids to yield corresponding salt and give off CO2 RE carbonates decompose to be oxides over 905℃.

Rear earth Nitrate Hydrous

RE nitrates can be prepared by condensing the solution of their salt which are obtained by mixing the nitric acid and RE oxide, hydroxide, carbonate. RE nitrates are most soluble in water of various salt and soluble in some organic agents-alcohol acetone etc. When the salts are heated, give off 02,NO,N02,the final products are oxides.

Rear earth Fluorides

RE fluorides are prepared by adding HF solution RE salt solution are insoluble in water, soluble in thick acid, and the major raw material for electrolysis of RE metal.

Rear Earth Metals

RE metals appear as of typical metallicity. Their melt points and densities increase with the atomic number except Europium and ytterbium, yet the hardness increases with the atomic number in spite of being soft. Although their tensile stresses are low, RE metals show fairly high stretchy .The activities of the Metals increase in sequence in Sc,Y,La, however decrease from La to Lu sequentially. The metals are liable to oxidize in the air, inert in cool water, but active to hot water and realease hydrogen and violently react with acids, but rather inactive to bases. The metals are combustible. As such should be kept carefully. Normally, RE metals are manufactured by electrolysis or pyroreduction. RE metals are rather effective reductants in metallurgical, the metals have been used to prepare high performance magnetics, fuel batteries, secondary cells, and functional non-ferrous materials.