aluminum hydroxideAnd alumina, although the name is similar, but in fact there is a difference, so how to distinguish between aluminum hydroxide and alumina.
Aluminium hydroxide:It is the hydroxide of aluminum. Aluminum hydroxide can react with acids to form salts and water, and can react with strong bases to form salts and water, so it is also an amphoteric hydroxide. The chemical formula Al(OH)3 is the hydroxide of aluminum. Because of its acidity, it can also be called aluminic acid (H3AlO3). However, the actual reaction with alkali is the formation of four hydroxy aluminate ([Al(OH)4]-). Therefore, it is usually regarded as monohydrated metaaluminic acid (HAlO2 · H2O), which is divided into industrial grade and pharmaceutical grade according to its application.
Alumina:It is a high hardness compound with a melting point of 2054 ° C and a boiling point of 2980 ° C. It is an ionizable ionic crystal at high temperatures and is often used in the manufacture of refractory materials. Industrial Al2O3 is prepared from bauxite (Al2O33H2O) and hard water aluminum stone, for the high purity requirements of Al2O3, generally prepared by chemical methods.
Al2O3 has many homogeneous and heterogeneous crystals, and there are more than 10 kinds of crystals known at present, mainly including 3 kinds of crystal forms, namely γ-Al2O3, β-Al2O3 and α-Al2O3 (corundum). Among them, the structure is different and the properties are different, and it is almost completely converted to α-Al2O3 at high temperatures above 1300°C.
The difference between alumina and aluminum hydroxide powder:
1. Their forms are different: aluminum hydroxide is a white precipitate and aluminum oxide is a solid. This is the easier to distinguish, from the appearance can be distinguished.
2. Different properties: aluminum hydroxide is amphoteric hydroxide, while aluminum oxide is amphoteric oxide, where aluminum oxide is the product of aluminum hydroxide.
The main way to distinguish them is to distinguish them from the appearance. In fact, in addition to the above two, it can also be judged by heating aluminum hydroxide, because aluminum hydroxide can be obtained after heating.