Aluminum is a light metal, and its compounds are widely distributed in nature. Aluminum is second only to oxygen and silicon in the earth's crust. Among the metal varieties, aluminum is the second largest metal after steel. Aluminum has special chemical and physical properties. It is one of the most commonly used industrial metals today. It is not only light in weight and strong in texture, but also has good ductility, electrical conductivity, thermal conductivity, heat resistance and nuclear radiation resistance. Important basic raw materials.
The density of aluminum is 2.7, which is about 1/3 of that of ordinary metals, and the conductivity of commonly used aluminum wires is about 61% of copper, and the thermal conductivity is half that of silver. Although pure aluminum is extremely soft and ductile, it can still be hardened by cold working and alloying. Bauxite is an important source of aluminum. It takes about two pounds of bauxite to make one pound of alumina, and two pounds of aluminum oxide to make one pound of metallic aluminum.
Aluminum exists in nature as oxides, hydroxides and oxygen-containing aluminosilicates. Natural metals in which aluminum is rarely found. There are currently 258 known aluminum-bearing minerals, of which about 43 are rare minerals. In fact, aluminum deposits composed of pure minerals are generally not symbiotic and mixed with impurities. From an economic and technological point of view, not all aluminum-bearing minerals can become industrial raw materials. Bauxite composed of diaspore, boehmite or gibbsite is mainly used for refining metallic aluminum.