Introduction and difference of aluminum, primary aluminum, electrolytic aluminum, aluminum ingot, and alumina

Electrolytic aluminum is a method of smelting metallic aluminum. Usually, aluminum oxide is decomposed into metallic aluminum through high current in an electrolytic cell.

Aluminum ingots are divided into high-purity aluminum ingots, aluminum alloy ingots and aluminum ingots for remelting according to their composition; according to their shape and size, they can be divided into round ingots, slab ingots, bar ingots, T-shaped ingots, etc.

Aluminum is a silver-white metal, and its content in the earth’s crust ranks third after oxygen and silicon. Aluminum has a low density, so it is called a light metal. Aluminum is a non-ferrous metal with high output and usage, 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 light, it is often used in land, sea and air transportation such as manufacturing, trains, subways, automobiles, airplanes, ships, rockets, etc. to reduce its own weight and increase the load. Similarly, aluminum also has a prominent position in military products.

Alumina, also known as aluminum oxide, is in the form of white powder. Primary aluminum is a liquid aluminum liquid produced during the electrolysis process and has not undergone precipitation or other treatments. The primary aluminum can become aluminum ingots by cooling in the cast aluminum ingot model. Therefore, alumina is the raw material of Yichu aluminum liquid, electrolytic aluminum is the process, primary aluminum is the aluminum liquid in the electrolysis process, and aluminum ingot is a kind of aluminum product that is finally sold on the market.

Electrolytic aluminum is the aluminum obtained by electrolysis. The production of modern electrolytic aluminum industry uses cryolite-alumina molten salt electrolysis. Molten cryolite is the solvent, alumina is used as the solute, the carbon body is used as the anode, and the aluminum liquid is used as the cathode. After a strong direct current is applied, the electrochemical reaction is carried out on the two poles in the electrolytic cell at 950°C-970°C. Both electrolysis.

Industrial aluminum ingot

The raw materials in our daily industry are called aluminum ingots. According to the national standard (GB/T 1196-2008), they should be called “aluminum ingots for remelting”, but everyone is used to calling them “aluminum ingots”. It is produced by electrolysis using alumina-cryolite. After aluminum ingots enter industrial applications, there are two major categories: cast aluminum alloys and deformed aluminum alloys. Cast aluminum and aluminum alloys are aluminum castings produced by casting methods; deformed aluminum and aluminum alloys are processed aluminum products produced by pressure processing methods: plates, strips, foils, tubes, rods, shapes, wires and forgings. According to the national standard, “remelting aluminum ingots are divided into 8 grades according to chemical composition, which are Al99.90, Al99.85, Al99.70, Al99.60, Al99.50, Al99.00, Al99.7E, Al99. 6E” (Note: The number after Al is the aluminum content). Some people call “A00” aluminum, which is actually aluminum with a purity of 99.7%, which is called “standard aluminum” in the London market. Everyone knows that my country’s technical standards in the 1950s came from the former Soviet Union. “A00” is the Russian brand in the Soviet national standard. “A” is a Russian letter, not English “A”, nor is it a Chinese phonetic alphabet. If “A” is in line with international standards, 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. It is an ionic crystal that can be ionized at high temperatures and is often used in the manufacture of refractory materials. Industrial Al2O3 is prepared from bauxite (Al2O3? 3H2O) and diaspore. For Al2O3 with high purity requirements, it is generally prepared by chemical methods.

Al2O3 has many homogenous and different crystals. At present, there are more than 10 kinds of known crystals. There are mainly 3 crystal types, 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 transformed into α-Al2O3 at a high temperature above 1300°C.