The invention discloses a method for producing and purifying
sulfur hexafluoride. The flow comprises units such as
reactive synthesis,
pyrolysis, alkaline wash, adsorption, rectification, gasification,
impurity circulating treatment and the like. The method comprises the following steps of: 1, reacting
fluorine with melted
sulfur in a reactor 3 to synthesize a coarse product of
sulfur hexafluoride; 2, allowing the coarse product of the
sulfur hexafluoride to pass through a
pyrolysis tower 4 at the temperature of 400 DEG C to be decomposed into S2F10 and S2F10O at high temperature; 3, introducing into a washing
tower 5 to remove acidic and hydrolyzable impurities such as HF, SF4 and the like; 4, intruding into an adsorption
drying tower 6 to remove water and part of low-
fluorine sulfur compounds; 5, removing light-component impurities such as CF4, THC, O2 and N2 and heavy impurities by using two levels of pressing rectification towers 8 and 9 to obtain the
sulfur hexafluoride product with the content of at least 99.8 percent and meeting the purity requirement from the top of the second-level rectification tower; and 6, allowing the
sulfur hexafluoride product to pass through a heat treater at the temperature of between 500 and 600 DEG C or directly returning the sulfur
hexafluoride product to a
fluorine charging
pipe, so that the sulfur hexafluoride product and the fluorine serve as raw materials to enter a synthetic reactor to take part in the reaction. The method is the most simple, convenient and ideal technology for preparing the sulfur hexafluoride.