Oxygen, chemical formula O2. Chemical formula: 32.00, colorless and odorless gas, the most common elemental form of oxygen element. The melting point is -218.4 ° C, and the boiling point is -183 ° C. Not easily soluble in water, about 30mL of oxygen in 1L of water. Oxygen accounts for about 21% in the air. Liquid oxygen is sky blue. Solid oxygen is a blue crystal. It is not very active at room temperature and is not easy to interact with many substances. However, it is very active at high temperatures and can directly combine with many elements, which is related to the electronegativity of oxygen atoms after fluorine.
Oxygen is the most widely distributed in nature, accounting for 48.6% of the crustal mass, and is the most abundant element. Oxygen is required for the oxidation of hydrocarbons, the treatment of wastewater, rocket propellants, and for breathing of animals and humans in aviation, aerospace and diving. Animals consume oxygen during breathing, burning and all oxidation processes, including the spoilage of organic matter. But the oxygen in the air can be continuously supplemented by photosynthesis of plants. In metal cutting and welding. It is a mixture of oxygen with a purity of 93.5% ~ 99.2% and a combustible gas (such as acetylene), which generates a flame at an extremely high temperature, thereby melting the metal. The metallurgical process cannot be separated from oxygen. Oxygen is also needed to strengthen the production of nitric and sulfuric acids. A mixture of oxygen and water vapor is blown into the coal gasifier without air, and gas with high heating value can be obtained. Medical gas is extremely important.
The main purpose
Smelting process: During the steelmaking process, high-purity oxygen is blown. Oxygen reacts with carbon and phosphorus, sulfur, and silicon, which not only reduces the carbon content of steel, but also helps to remove impurities such as phosphorus, sulfur, and silicon. . Moreover, the heat generated during the oxidation process is sufficient to maintain the temperature required for the steelmaking process. Therefore, oxygen blowing not only shortens the smelting time, but also improves the quality of the steel. When blast furnace ironmaking, increasing the oxygen concentration in the blast can reduce the coke ratio and increase the output. In the smelting of non-ferrous metals, the use of oxygen can also shorten the smelting time and increase production.
Chemical industry: In the production of synthetic ammonia, oxygen is mainly used for the oxidation of raw gas to strengthen the process and increase the output of fertilizers. Another example is the high temperature cracking of heavy oil and the gasification of pulverized coal.
National Defense Industry: Liquid oxygen is the best combustion aid for modern rockets. Liquid oxygen is also required as an oxidant in supersonic aircraft. Combustible substances are strongly explosive when impregnated with liquid oxygen and can be used to make liquid oxygen explosives.
Healthcare: Provide breathing: used in hypoxic, hypoxic or anaerobic environments, such as diving, mountain climbing, high-altitude flight, space navigation, medical rescue, etc.
Other aspects: It is used as a combustion accelerator in combination with acetylene, propane and other flammable gases to achieve the role of welding and cutting metals. It is widely used in various industries, especially in machinery enterprises, and it is also very convenient for cutting. A cutting method.