Introduction and difference between aluminum, primary aluminum, electrolytic aluminum, aluminum ingots, and alumina
Electrolytic aluminum is a method of smelting metallic aluminum, usually in the electrolyzer through high current to decompose alumina into metallic aluminum.
Aluminum ingots are divided into three types according to different compositions: high-purity aluminum ingots, aluminum alloy ingots and aluminum ingots for remelting; According to the shape and size, it can be divided into round ingots, plate ingots, strip ingots, T-shaped ingots, etc.
Aluminum is a silvery-white metal that ranks third in the earth's crust after oxygen and silicon. Aluminum has a low density, so it is called a light metal. Aluminum is a non-ferrous metal with high production and use, second only to steel in the world. The density of aluminum is about 1/3 of the density of steel and copper. Because aluminum is lightweight, it is often used in manufacturing, trains, subways, automobiles, airplanes, ships, rockets and other land, sea and air vehicles to reduce its own weight and increase loading capacity. Similarly, aluminum has a prominent position in military products.
Alumina, also known as aluminum trioxide, comes in the form of white powder. Primary aluminum is a liquid aluminum liquid released during the electrolysis process, which has not been treated by precipitation and other treatments. Primary aluminum can be made into aluminum ingots by cooling it in the cast aluminum ingot model. Therefore, alumina is the raw material of the aluminum liquid, electrolytic aluminum is the process, primary aluminum is the aluminum liquid in the electrolysis process, and aluminum ingots are an aluminum product, which is finally a sellable product on the market.
Electrolytic aluminum is aluminum obtained by electrolysis. The modern electrolytic aluminum industry uses cryolite-alumina molten salt electrolysis method. Molten cryolite is a solvent, alumina as the solute, carbon body as the anode, aluminum liquid as the cathode, through the powerful direct current, at 950 °C-970 °C, electrochemical reaction is carried out on the two poles in the electrolyzer, both electrolysis.
Industrial aluminum ingots
The raw material in our daily industry is called aluminum ingot, which should be called "aluminum ingots for remelting" according to the national standard (GB/T 1196-2008), but everyone is used to calling it "aluminum ingots". It is produced by electrolysis of alumina cryolite. After aluminum ingots enter industrial applications, there are two main categories: cast aluminum alloys and deformed aluminum alloys. Cast aluminum and aluminum alloys are castings that produce aluminum by casting method; Deformed aluminum and aluminum alloys are processed products from which aluminum is produced by pressure machining methods: plates, strips, foils, tubes, rods, molds, wires, and forgings.According to the national standard, "aluminum ingots for remelting are divided into 8 grades according to their chemical composition, namely Al99.90, Al99.85, Al99.70, Al99.60, Al99.50, Al99.00, Al99.7E, and Al99.6E" (Note: The number after Al is the aluminum content). Some people call it "A00" aluminum, but it is actually aluminum with a purity of 99.7%, which is called "standard aluminum" in the London market. Everyone knows that our country's technical standards in the fifties came from the former Soviet Union, "A00" is the Russian grade in the Soviet national standard, "A" is the Russian letter, not the English "A" word, and it is not the Chinese pinyin letter "A" and the international standard, it is more accurate to call "standard aluminum". Standard aluminum is an aluminum ingot containing 99.7% aluminum, which is registered on the London market.
Alumina (Al? O?) is a high-hardness compound with a melting point of 2054°C and a boiling point of 2980°C, which is an ionic crystal that can be ionized at high temperatures and is often used to make refractory materials. Industrial Al2O3 is prepared from bauxite (Al2O3?3H2O) and hard diaspore, and Al2O3, which requires high purity, is generally prepared by chemical methods.
Al2O3 has many homogeneous isocrystals, and there are more than 10 known ones, mainly with 3 crystal forms, namely γ-Al2O3, β-Al2O3, and α-Al2O3 (corundum). Among them, the structure and properties are also different, and it is almost completely converted to α-Al2O3 at high temperatures above 1300°C.
