NOx conversion catalyst rejuvenation process

A method for cleaning and rejuvenating an at least partially spent de-NOx catalyst comprising a porous ceramic metal oxide material containing a vanadium oxide and coated on a metal support, the method comprising:

• a) contacting the catalyst with an aqueous oxalic acid solution containing from about 1 to about 4 weight percent oxalic acid for a time from about 30 to about 60 seconds to produce a cleaned catalyst;
• b) drying the cleaned catalyst to produce a dried, cleaned catalyst;
• c) contacting the dried, cleaned catalyst with an aqueous vanadium compound solution containing from about 10 to about 100 g/L as V2O5 of at least one water soluble vanadium salt for a time from about 30 to about 60 seconds to produce a rejuvenated catalyst;
• and,
• d) drying the rejuvenated catalyst.