The content of aluminum in the earth's crust is 8%. Due to the strong chemical affinity of aluminum, it is impossible to exist in the state of metal in nature. It generally exists in the state of compounds such as aluminum oxide, aluminum silicate, aluminum sulfate, and their composite salts or hydrates.
Aluminum is a silver-white metal that is widely distributed in nature. The current annual output of aluminum in the world is second only to steel and ranks first among non-ferrous metals. The important feature of aluminum is its low density. Aluminum is a face-centered cubic crystal in solid state, which has good plasticity and can be subjected to various forms of pressure processing in hot and cold states.
Aluminum is corrosion resistant. The surface of pure aluminum is covered with a dense and tough colorless transparent oxide film, which can resist the corrosion of wind and rain, food, nitrate, natural gas, etc. Chemical or anodic oxidation treatment of aluminum can increase the thickness of the surface oxide film and further improve the corrosion resistance. It can also use the porous structure of the anodic oxide film to absorb dyes and heavy metal ions and dye them into various beautiful and light fast colors.
Aluminum has sufficient strength, high reflectivity, good electrical and thermal conductivity, and good ductility. Aluminum is impact-resistant, so aluminum components under impact load, although the amount of elastic deformation is greater than that of steel components with the same cross-section, it is not prone to fracture or permanent deformation.
The recycling rate of aluminum is high.
