Zirconia is a metal element, the element symbol is zro2, and it is a silver-white light metal. There is malleability. Commodities are often made into rods, flakes, foils, powders, ribbons and filaments. It can form an oxide film to prevent metal corrosion in humid air. Aluminum powder can burn violently when heated in the air and emit a dazzling white flame. It is easily soluble in dilute sulfuric acid, nitric acid, hydrochloric acid, sodium hydroxide and potassium hydroxide solution, but hardly soluble in water. The relative density is 2.70. Melting point is 660°C. The boiling point is 2327°C. The content of aluminum in the earth's crust is second Ceramic Disc only to oxygen and silicon, ranking third, and it is the most abundant metal element in the earth's crust. The development of the three important industries of aviation, construction, and automobiles requires the characteristics of materials to have the unique properties of aluminum and its alloys, which greatly facilitates the production and application of this new metal aluminum. The application is extremely wide.
On October 27, 2017, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization was preliminarily compiled for reference, and aluminum products were included in the list of carcinogens in the first category. In 1854, the French chemist Deville mixed bauxite, charcoal, and table salt, and then heated it with chlorine gas to obtain NaCl, AlCl₃ double salt, and then melted the double salt with excess sodium to obtain metal aluminum. In 1886, Howe of the United States and Hylandt of France independently electrolyzed a mixture of molten bauxite and cryolite (Na3AlF6) to produce metallic aluminum, laying the foundation for large-scale aluminum production in the future. Aluminum exists in various rocks or ores in the form of a chemical state, such as feldspar, mica, kaolinite, bauxite, alunite and so on. Aluminum can be produced by eutectic electrolysis of aluminum oxide and cryolite (Na3AlF6). The main reaction process is as follows: aluminum Ceramic Disc is extracted from bauxite, and the reaction process is dissolved: bauxite is dissolved in NaOH(aq): Al2O3+ 2NaOH+ 3H2O= 2NaAl(OH)4 (sodium tetrahydroxy aluminate)
Filtration: Removal of residual ferrous oxide (FeO), sodium aluminosilicate, etc.
Acidification: pass excess CO₂ into the filtrate: NaAl(OH)4+ CO₂ = Al(OH)3↓+ NaHCO3
Filtering and burning Al(OH)₃: 2Al(OH)₃ = high temperature = Al₂O₃+ 3H₂O
Electrolysis: Note: In order to lower the melting temperature of alumina during electrolysis, cryolite (Na₃AlF6) is added to Al₂O₃. Do not melt AlCl3 electrolytically to make Al; Reason: AlCl3 is a covalent compound, and its molten state has very poor conductivity. The English name of aluminum (Aluminium) comes from alum (alum), which is the double salt of sulfate KAl(SO4)2·12H2O. In prehistoric times, humans have used clay containing aluminum compounds (Al2O3·2SiO2·2H2O) to make pottery. The content of aluminum in the earth's crust is second only to oxygen and silicon, ranking third. However, due to the weak oxidation of aluminum compounds, aluminum is not easily reduced from its compounds, so metallic aluminum cannot be separated for a long time. After the Italian physicist Volta invented the battery, David tried to use electric current to separate the metal aluminum from the alumina, but it was unsuccessful, but he suggested that it be named "alumium" and later changed to "aluminum", Ceramic Disc which will soon be modified to aluminium. This word form is common throughout the world, except for North America, where the American Chemical Society (ACS) decided in 1925 to use "aluminum" in publications.
The chemical symbol Al, belongs to group IIIA in the periodic table of elements, atomic number 13, atomic weight 26.98154, face-centered cubic crystal, common valence is +3. Aluminum is the most important light metal.
How to do the metallization of ceramics?
2021 06/21