Alumina

Alumina, chemical symbol: Al2O3, molecular weight 102, pure alumina is a white amorphous powder, commonly known as bauxite, density 3.9-4.0g/cm3, melting point 2050 ℃, boiling point 2980 ℃, insoluble in water, is an amphoteric oxide, can Dissolved in mineral acids and alkaline solutions, there are four allotropes β-alumina δ-alumina v-alumina a-alumina, mainly α-type and γ-type two variants, which can be used in industry. Obtained from bauxite.

Properties: White solid insoluble in water, odorless, tasteless, extremely hard, easy to absorb moisture but not deliquescence (burned does not absorb moisture). Amphoteric oxide, soluble in inorganic acid and alkaline solution, almost insoluble in water and non-polar organic solvent; relative density (d204) 4.0; melting point 2050℃.

Storage: Seal dry and keep. SCRC100009

Uses: used as analytical reagents, dehydration of organic solvents, adsorbents, organic reaction catalysts, abrasives, polishing agents, raw materials for smelting aluminum, and refractory materials.

In the lattice of α-type alumina, the oxygen ions are tightly packed in hexagons, and Al3+ is symmetrically distributed in the middle of the octahedral coordination surrounded by oxygen ions. The lattice energy is large, so the melting point and boiling point are very high. Alpha alumina is insoluble in water and acid, also known as aluminum oxide in industry, and is the basic material for making metal aluminum; it is also used to make various refractory bricks, refractory crucibles, refractory pipes, and high temperature test instruments; it can also be used as an abrasive , flame retardants, fillers, etc.; high-purity alpha alumina is still the raw material for the production of artificial corundum, artificial ruby ​​and sapphire; it is also used to produce the substrate of modern large-scale integrated circuits.

γ-type alumina is obtained by dehydration of aluminum hydroxide at a low temperature of 140-150 ° C, and is also called activated alumina and aluminum glue in industry. In its structure, the oxygen ions are approximately closely packed in cubic centroids, and Al3+ is irregularly scattered in the octahedral and tetrahedral voids surrounded by oxygen ions. γ-type alumina is insoluble in water, but can be dissolved in strong acid or strong alkali solution, and it will be completely converted into α-type alumina when it is heated to 1200 °C. γ-type alumina is a porous material, with an internal surface area of ​​hundreds of square meters per gram, and high activity and strong adsorption capacity. Industrial products are usually colorless or slightly pink cylindrical particles with good pressure resistance. It is a commonly used adsorbent, catalyst and catalyst carrier in petroleum refining and petrochemical industry; it is a deacidifying agent for transformer oil and turbine oil in industry, and is also used for chromatographic analysis; it is a neutral strong drying agent in the laboratory , its drying ability is no less than phosphorus pentoxide, and it can be regenerated and reused after heating for 6-8h below 175 °C.

At present, the alumina produced by the Bayer process in the world accounts for more than 90% of the total output. Most of the alumina is used to make metal aluminum, and less than 10% is used for other purposes.

Henan Shiyuan Aluminum Technology Co., Ltd. was established in August 2019 with a registered capital of 1 million yuan. It is located in Shangjie District, Zhengzhou City. It has established long-term scientific research and cooperative relations with Central South University, Chinese Academy of Sciences, Zhengzhou Research Institute, and related industries. , The senior experts in the company have made remarkable achievements in research and development, technical services and independent innovation in related fields.