METHOD FOR MAKING UHP TUNGSTEN HEXAFLUORIDE

摘要

This invention is directed to a method forproducing UHP tungsten hexafluoride by introducing anamount of crude tungsten hexafluoride to an evaporatingprocess for separation into an amount of tungstenhexafluoride-containing volatile impurities and anamount of non-volatile metallic impurities; passing theamount of tungsten hexafluoride-containing volatileresidue to a gas phase adsorption process forseparation into an amount of semi-crude tungstenhexafluoride product and an amount of hydrogen fluoridenon-volatile residue; and passing the amount of semi-crudetungsten hexafluoride product to a spargingsystem using UHP helium for separation into anon-volatile UHP tungsten hexafluoride product.