Do you often hear about sulfur hexafluoride gas, but how much do you really know? How to make gas? What is the preparation method? The editor today shares with you the preparation process of sulfur hexafluoride, hoping to help you!
Let’s take a look at the history of sulfur hexafluoride gas first. In 1900, Moissan and Lebeau first produced sulfur hexafluoride by burning sulfur in fluorine gas. In 1930, Schumb and Gamble also proposed a method for manufacturing sulfur hexafluoride. In 1941, Britain proposed the use of hexafluoride in transformers. Sulfur. In 1942, the Soviet Union also used sulphur hexafluoride in cables and accumulators. The United States started industrial production of sulphur hexafluoride in 1948. Now the United States, Britain, France, Germany, Italy, Russia, Japan, etc. The production of sulfur hexafluoride, especially the Japanese Kanto Denka Company and Asahi Glass Co., Ltd., had a production capacity of 1,000 t/a of sulfur hexafluoride in the 1970s.
Industrial sulfur hexafluoride gas is usually prepared by the reaction of fluorine produced by electrolysis with sulfur at medium and high temperature. In addition to sulfur hexafluoride, a small amount of by-products such as sulfur tetrafluoride (SF4) is also generated. The method of directly synthesizing sulfur hexafluoride from fluorine-sulfur can be divided into three methods: fluorine gas and solid sulfur, molten sulfur, and sulfur vapor: fluorine gas reacts with solid sulfur. Since the fluorine-sulfur reaction is a very intense exothermic reaction, The reaction temperature is not easy to control, resulting in increased by-products and increased post-processing burden. In addition, it is difficult to continuously add solid sulfur to a sealed reactor, so this method is not suitable for industrial production. The reaction of fluorine gas with sulfur vapor is to heat the sulfur to above 445 ℃ (boiling point), so that the sulfur becomes vapor and is sent to the reactor to react with fluorine. There is also the defect that the reaction temperature is difficult to control, and the reaction temperature can reach 600 Above ℃, special reactor materials must be used, and this method is not suitable for industrial production. The reaction of fluorine gas with molten sulfur is to keep the sulfur in the reactor in a molten state at 85-105°C to react with the fluorine gas introduced. This method is easier to control the reaction temperature.
Sulfur hexafluoride gas is a colorless, odorless, non-toxic, non-flammable and non-corrosive gas at normal temperature and pressure. The gas density is 61139 g/L, and its chemical stability is strong. It will not decompose at 500-600 ℃, and Acid, alkali, salt, ammonia, water, etc. do not react, and decompose into atomic gas of S and F under the action of an arc (thousands of degrees), but once the arc is released, it will recombine into SF6 within 0-5 ～10-6 s. . Sulfur hexafluoride has good electrical properties and excellent arc extinguishing performance. Its electric strength is 215 times that of nitrogen under the same pressure, its breakdown voltage is 215 times that of air, and its arc extinguishing ability is 100 times that of air. A new-generation ultra-high-edge media material superior to air and oil.
High purity sulfur hexafluoride has stable chemical properties. Slightly soluble in water, alcohol and ether, soluble in potassium hydroxide. Does not react chemically with sodium hydroxide, liquid ammonia, hydrochloric acid and water. It does not react with copper, silver, iron, and aluminum in a dry environment below 300°C. Below 500℃, it has no effect on quartz. It reacts with metallic sodium at 250°C, and reacts in liquid ammonia at -64°C. It will be decomposed when mixed with hydrogen sulfide and heated. At 200℃, in the presence of certain metals such as steel and silicon steel, it can promote its slow decomposition.
Customer Service