China Alumina Sand Exporter

Alumina sand can also be used as the bearing of precision instruments, the diamond, grinding wheel, polishing agent, refractory and electrical insulator of clocks and watches. Colorful gemstones can be used for decoration. Synthetic ruby single crystal can be used as laser material. In addition to natural minerals, it can be made by melting aluminum hydroxide with hydrogen oxygen flame. Aluminum oxide is the reason that metal aluminum is not easy to be corroded in air. Pure metal aluminum can easily react with oxygen in the air to form a thin layer of aluminum oxide film on the aluminum surface exposed to the air. This aluminum oxide film can prevent aluminum from being further oxidized. The thickness and properties of oxide films can be enhanced by a process called anodic treatment (anodic corrosion protection).

Alumina sand is suitable for a variety of dry and wet treatment processes. It can grind the rough surface of any workpiece finely. It is one of the most economical abrasives. This kind of sharp synthetic abrasive with rhombus has the hardness second only to that of diamond, and is especially suitable for use when there are strict requirements for iron pollution. It is used for the roughest cutting, and can also be made into pebbles to process workpieces with precise dimensions to achieve extremely low roughness. Because of its high density, sharp and rhombic structure, it is one of the fastest cutting abrasives.

Alumina sand with high hardness can be used as abrasive, polishing powder, high-temperature sintered aluminum oxide, called artificial corundum or artificial gem, and can be used to make mechanical bearings or diamonds in clocks and watches. Alumina is also used as high-temperature refractory materials to make refractory bricks, crucibles, porcelain, artificial gemstones, etc. Alumina is also the raw material for aluminum smelting. It can be made by calcining aluminum hydroxide γ- Al2O3。 γ- Al2O3 has strong adsorption and catalytic activity and can be used as adsorbent and catalyst.

Alumina sand is mainly composed of aluminum oxide in barrel or cone shaped triangular crystals. It has glass luster or diamond luster. The density is 3.9 ～ 4.1g/cm3, the hardness is 9, and the melting point is 2000 ± 15 ℃. It is insoluble in water, acid and alkali. High temperature resistance. The colorless and transparent one is called white jade, and the red one containing trace trivalent chromium is called ruby; Blue color containing divalent iron, trivalent iron or tetravalent titanium is called sapphire; The dark gray and dark color containing a small amount of ferric oxide is called corundum powder.