If the purity of high-purity sulfur hexafluoride is low, its insulation strength will be greatly reduced. When used in electrical insulation, it is easy to be broken down by high voltage, causing accidents. It is known from the test and research results of relevant departments. What are the reasons for the impurity?

High purity sulfur hexafluoride is impure and contains toxic gases such as highly toxic sulfur fluoride, hydrogen fluoride, etc. As we all know, at present, the chemical industry mainly manufactures high-purity sulfur hexafluoride by direct combination of elemental sulfur and excess gaseous fluorine; That is, S+3F2 → SF6+Q (heat released). The crude product contains a variety of impurities. The composition and content of impurities vary greatly due to the purity of raw materials, the materials of production equipment, process conditions and other factors. The total content of impurities can reach 5%. It consists of sulfur fluoride compounds, such as S2, F2, SF2, SF4, etc; Sulfofluoroexide compounds such as SOF2, SO2F2, SOF4, etc. and impurities introduced into raw materials such as HF, OF2, CF4, N2, O2, etc.

In order to purify impurities in crude products, the synthesized sulfur hexafluoride gas also needs a series of purification processes such as water washing, alkali washing, pyrolysis (to remove highly toxic decafluoride), drying, adsorption, freezing, distillation and purification to obtain a product with a purity of more than 99.8%. Then, pressurize it with a compressor and fill it into a cylinder cooled to about - 80 ℃, which exists in liquid form. It is discharged under reduced pressure during use and rushed into the electrical equipment as a gas.

In addition to the impurities generated in the above synthesis process, a small amount of air, water, mineral oil and other impurities may be mixed in the filling process of sulfur hexafluoride gas manufacturers. These impurities carry or produce certain toxic substances. Therefore, in order to ensure the purity and quality of sulfur hexafluoride, the International Electrotechnical Commission (IEC) of sulfur hexafluoride and many countries have formulated quality standards for the ex factory sulfur hexafluoride, and the manufacturer is required to provide the non-toxic certificate of biological test when supplying.

The content of the article comes from high-purity sulfur hexafluoride: http://www.feiliergas.com