Abstract: An aqueous solution containing fluorides, for example, hydrofluoric acid, is reacted with commercial grade aluminum oxide comprising predominantly alpha alumina at an elevated temperature to produce a complex aluminum hydroxide fluoride hydrate that precipitates from the solution. The commercial grade aluminum oxide contains an amount of gamma and delta alumina such that the aluminum oxide has a loss of weight on ignition of from about 0.5% to about 2.5%. The resulting aluminum hydroxide fluoride hydrate precipitate is recovered and calcined in a non-oxidizing atmosphere to produce aluminum fluoride suitable for use in the electrolytic production of aluminum.