METHOD FOR MAKING UHP TUNGSTEN HEXAFLUORIDE

摘要

This invention is directed to a method for producing UHP tungsten hexafluoride by introducing an amount of crude tungsten hexafluoride to an evaporating process for separation into an amount of tungsten hexafluoride-containing volatile impurities and an amount of non- volatile metallic impurities; passing the amount of tungsten hexafluoride- containing volatile residue to a gas phase adsorption process for separation into an amount of semi-crude tungsten hexafluoride product and an amount of hydrogen fluoride non-volatile residue; and passing the amount of semi-crude tungsten hexafluoride product to a sparging system using UHP helium for separation into a non- volatile UHP tungsten hexafluoride product.