Method for calcining crystalline (metallo)aluminophosphate compositions

A method for calcining a dried crystalline aluminophosphate having pore windows of at least about 10 Angstroms, which comprises a) contacting said aluminophosphate in a calcination zone with a non-oxidizing gas while heating said aluminophosphate to calcining temperature at a heating rate no greater than 10.degree. C./minute and maintaining said contact at said calcining temperature for a period of from 1 to 48 hours;

• b) introducing an oxygen-containing gas to said calcination zone in addition to said non-oxidizing gas and maintaining contact with said aluminophosphate for a period of from 0.5 to 10 hours;
• c) contacting said aluminophosphate in said calcination zone with an oxygen containing gas for a period of from 1 to 10 hours;
• and d) contacting said aluminophosphate with a cooling non-oxidizing gas for a period of time sufficient to reduce the temperature of said aluminophosphate to a temperature of 20.degree. to 30.degree. C.;
• wherein the total flow rate of said non-oxidizing and oxygen-containing gases in steps a) through d) ranges from 100 to 500 cc/minute per gram of aluminophosphate, wherein said aluminophosphate is dried by treatment under a vacuum of 0.05 to 10 torr prior to step a).