his product is non-toxic, odorless, odorless, white colloidal (wet product) or powder (dry product), with high crystal phase purity, good peptization performance, strong adhesion and thixotropic gel characteristics. Mainly used in catalytic cracking catalyst, hydrogenation catalyst carrier. The low-sodium pseudo-boehmite can be used as a binder for a complete rare-earth Y-type molecular sieve cracking catalyst, a binder for aluminum silicate refractory fibers, an ethylene catalyst for dehydration of alcohol and a catalyst for ethylene oxide, etc. Raw materials for alumina and other aluminum salts.
Aluminum oxide (aluminium oxide), chemical formula Al2O3. It is a high hardness compound with a melting point of 2054 ° C and a boiling point of 2980 ° C. It is an ion crystal that can be ionized at high temperatures and is commonly used in the manufacture of refractory materials.
Industrial alumina is prepared from bauxite (Al2O3 · 3H2O) and diaspore. For Al2O3 with high purity requirements, it is generally prepared by chemical methods. Al2O3 has many homogeneous crystals, there are more than 10 kinds known, there are mainly three kinds of crystal forms, namely α-Al2O3, β-Al2O3, γ-Al2O3. Among them, the structure and properties are also different, and it is almost completely converted into α-Al2O3 at high temperature above 1300 ℃.
Corundum, alumina, alumina
Alumina contains the elements aluminum and oxygen. If the bauxite raw material is chemically treated to remove silicon, iron, titanium and other oxides, the product obtained is an alumina raw material with very high purity, and the Al2O3 content is generally above 99%. The mineral phase is composed of 40% to 76% γ-Al2O3 and 24% to 60% α-Al2O3. γ-Al2O3 can be transformed into α-Al2O3 at 950 ～ 1200 ℃, and significant volume shrinkage occurs at the same time.
Reacts with acid:
Al2O3 + 6HCl = 2AlCl3 + 3H2O
Al2O3 + 6H + = 2Al3 + + 3H2O
Reacts with molten alkali:
Al2O3 + 2NaOH == 2NaAlO2 (sodium meta aluminate) + H2O
React with alkaline solution:
Al2O3 + 2NaOH + 3H2O = 2Na [Al (OH) 4] (tetrahydroxy sodium aluminate)
It can also be abbreviated as: Al2O3 + 2OH- = 2AlO2- (metaluminate ion) + H2O
InChI = 1 / Al.2O / rAlO2 / c2-1-3
Formula volume: 101.96 amu
Melting point: 2303 K
Boiling point: 3250 K
True density: 3.97 g / cm3
Bulk density: 0.85 g / mL (325 mesh ~ 0) 0.9 g / mL (120 mesh ~ 325 mesh)
Crystal structure: Trigonal system (hex)
Solubility: insoluble in water at room temperature
Conductivity: non-conductive at room temperature
Al2O3 is an ionic crystal
ΔfH0liquid 1620.57 kJ / mol
ΔfH0solid 1675.69 kJ / mol
S0liquid, 1 bar 67.24 J / mol · K
S0solid 50.9 J / mol · K