Process for the preparation of aluminum fluoride

Abstract

Process for preparing aluminum fluoride having an high surface area and high pore volume comprising the fluorination with HF of alumina having surface area of at least 150 m 2 /g and pore volume not lower than 0.3 cc/g, said alumina comprising from about 0.5 up to about 15% by weight of silicon oxide.

1 . A process for preparing aluminum fluoride having an high surface area and high pore volume comprising the fluorination with HF in gas phase of alumina having a surface area of at least 150 m 2 /g and pore volume not lower than 0.3 cc/g, said alumina comprising from about 0.5 up to about 15% by weight of silicon oxide.  
     
     
         2 . Process for preparing aluminum fluoride according to    claim 1   , wherein the amount of silicon oxide is comprised between 1 and 10% by weight.  
     
     
         3 . Process for preparing aluminum fluoride according to claims  1  and  2 , wherein the aluminum fluoride has a fluorine content not lower than 90%.  
     
     
         4 . Process for preparing aluminum fluoride according to    claim 3   , wherein the fluorine content is not lower than 95%.  
     
     
         5 . Process for preparing aluminum fluoride according to claims from  1  to  4 , wherein the fluorination of the alumina containing silica is carried out at a temperature between about 250° C. and about 450° C., preferably higher than 300°-400°C.  
     
     
         6 . Process for preparing aluminum fluoride according to claims from  1  to  5 , wherein the partial pressure of HF is comprised between 0.1 and 0.5.  
     
     
         7 . Process for preparing aluminum fluoride according to    claim 6   , wherein HF diluted with a gas inert under fluorination conditions, preferably air or nitrogen, is used.  
     
     
         8 . Process for preparing aluminum fluoride according to claims from  1  to  7 , wherein the fluorination reaction is carried out in fluidized bed.  
     
     
         9 . Aluminum fluoride obtainable with the process according to claims from  1  to  8 , wherein AlF 3  has generally a surface area not lower than 25 m 2 /g, preferably not lower than 30 m 2 /g and a pore volume not lower than 0.20 cc/g, preferably 0.25 cc/g.  
     
     
         10 . Aluminum fluoride according to    claim 9   , wherein AlF 3  is mainly formed by the gamma phase.