Purification of hydrogen fluoride

A process for purifying crude anhydrous hydrogen fluoride containing phosphate and other impurities, said process comprising the steps of distilling said crude anhydrous hydrogen fluoride to remove at least a portion of said other impurities and contacting the distilled anhydrous hydrogen fluoride with activated carbon under conditions effective to produce purified anhydrous hydrogen fluoride having a phosphate impurity content less than about 5 ppm.

A process for purifying crude anhydrous hydrogen fluoride containing greater than a predetermined amount of at least one impurity, said process comprising adsorbing a sufficient quantity of said at least one impurity onto activated carbon to produce purified hydrogen fluoride containing less than about said predetermined maximum amount of said at least one impurity.

A process for producing a purified anhydrous hydrogen fluoride stream comprising less than about 0.1 ppm phosphate impurity from a crude anhydrous hydrogen fluoride stream containing greater than about 10 ppm of phosphate impurity and at least one other impurity, said process comprising:

• a) distilling said crude anhydrous hydrogen fluoride to remove at least a portion of said other impurity, and optionally a portion of said phosphate impurity, to produce a partially purified hydrogen fluoride stream comprising greater than about 0.1 ppm of phosphate impurity;
• and
• b) removing a sufficient quantity of said phosphate impurity from said partially purified hydrogen fluoride stream to produce a purified hydrogen fluoride steam containing less than about 0.1 ppm of phosphate impurity, said removing step comprising substantially continuously contacting said partially purified hydrogen fluoride stream with a fixed bed of activated carbon in particulate form.