Process for regeneration of iron-antimony metallic oxide catalysts

A process for regenerating an iron-antimony metallic oxide catalyst containing as essential components (I) Fe, (II) Sb, (III) at least one element selected from the group consisting of V, Mo, and W and (IV) Te, which has become deactivated after being used for the production of nitriles through ammoxidation or hydrocarbons or alcohols in fluidized-bed reactors, said process comprising adding to said catalyst dry solid molybdenum or a dry solid molybdenum compound which is volatile or capable of forming a volatile compound under reaction conditions in such an amount that the apparent content of molybdenum in the catalyst increases by 0.1 to 2 wt%, and performing the ammoxidation in the presence of the mixture of said deactivated catalyst and said solid molybdenum or molybdenum compound, wherein said molybdenum or solid molybdenum compound is not supported on an inert carrier, wherein said solid molybdenum compound is selected from the group consisting of molybdenum dioxide, molybdenum trioxide, molybdic acid, ammonium molybdate, ammonium paramolybdate, phosphomolybdic acid, ammonium phosphomolybdate, heteropoly acids or molybdenum and salts thereof, molybdenum disulfide, molybdenum trisulfide, molybdenum dichloride, molybdenum trichloride, molybdenum pentachloride, and organic molybdenum compounds which are solid at ordinary temperature, wherein the catalyst is in the form of particles having a diameter of 1 to 500 microns, the solid dry molybdenum or solid dry molybdenum compound is in the form of particles having a diameter of 0.1 to 5,000 microns, and the catalyst is mixed with the solid dry molybdenum or solid dry molybdenum compound when the catalyst is in a fluidized state.