Method for purifying tungsten hexafluoride

The invention relates to a kind of purification method of tungsten hexafluoride gas. First, put impure tungsten hexafluoride gas in the storage tank of crude product into the bottom of absorption column where there are multihole spherical filling of sodium fluoride or potassium fluoride, remove the most impurity of hydrogen fluoride under temperature of 10-80 degree C,put it into rectifying column through pipe and fluidify it, stop entering tungsten hexafluoride gas after fluidifing it for 5kg-50kg, put helium gas of high purity into bottom of tungsten hexafluoride liquid and keep it boiling under temperature between 3 degree C and 20 degree C,the vaporized gas enter rectification column and rises, it gradually gets into condensation and circumfluence during the process of rising ,continues to rectify it to remove impurity, check it with gas chromatography, when concentration of impurity of gas discharged from tower top whose boiling point is higher than that of tungsten hexafluoride gas reduce to the request index, stop entering helium gas of high purity, and when helium gas's index reaches the request, collect tungsten hexafluoride gas of high purity into storage tank of quality product.