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A process is disclosed for reactivating an agglomerated iridium-containing catalyst and particularly platinum-iridium on alumina reforming catalysts. The process includes a reducing step involving contacting a decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated

A process is disclosed for reactivating an agglomerated iridium-containing catalyst and particularly platinum-iridium on alumina reforming catalysts. The process includes a reducing step involving contacting a decoked agglomerated catalyst with a reducing gas such as hydrogen to reduce agglomerated iridium oxides to the free metal, a hydrogen halide pretreatment step to provide a halide level to the catalyst of about 1.3 weight percent, and an elemental halogen redispersion step. The hydrogen halide pretreatment step is performed under elemental oxygen-free conditions prior to redispersion and allows high iridium redispersion values to be obtained. If no iridium oxides are initially present, the hydrogen step is optional.

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A process for reactivating an agglomerated catalyst containing metallic iridium comprising the steps of: (a) pretreating the catalyst by contact with a substantially elemental oxygen-free atmosphere comprising a halide-providing compound at an elevated temperature to provide about 1.3 weight percent

A process for reactivating an agglomerated catalyst containing metallic iridium comprising the steps of: (a) pretreating the catalyst by contact with a substantially elemental oxygen-free atmosphere comprising a halide-providing compound at an elevated temperature to provide about 1.3 weight percent and above, halide to the catalyst, taken as the coke-free dry, catalyst; and (b) redispersing the metallic iridium from step (a) while maintaining said 1.3 weight percent and above halide provided to the catalyst by contact at an elevated temperature with an atmosphere comprising elemental halogen and a redispersing aid selected from elemental oxygen, or elemental oxygen and water, wherein said halogen and oxygen are present in a halogen to oxygen volume ratio in the range of about 0.05 to 10, for a time sufficient to substantially redisperse said metallic iridium. The process of claim 1 wherein said halide-providing compound is one which generates a hydrogen halide in the presence of hydrogen gas. A process for reactivating an agglomerated platinum-iridium on alumina catalyst, containing platinum and iridium oxides, comprising the steps of: (a) contacting said agglomerated catalyst with a hydrogen atmosphere at a temperature in the range of about 300°to 540°C., a pressure of about 0.1-2 MPa, for a sufficient time to substantially reduce said oxides of platinum and iridium to the respective metals; (b) pretreating said catalyst from step (a) by contact with an elemental oxygen-free atmosphere comprising hydrogen chloride at a temperature in the range of about 300°to 540°C. and a pressure of about 0.1-2 MPa for a time sufficient to saturate the catalyst with chloride; and (c) redispersing the metallic iridium and platinum while maintaining a saturated chloride level by contact with an atmosphere comprising elemental chlorine and elemental oxygen and water in a chlorine to oxygen volume ratio of about 0.2 to 5 at a temperature in the range of about 500°to 540°C., and a pressure of about 0.1-2 MPa for a time sufficient to effect about a 75-100% redispersion of both metallic platinum and iridium. A process for reactivating an agglomerated metallic platinum-iridium on alumina catalyst, which has been partially decoked by hydrogen gas, comprising the steps of: (a) pretreating said catalyst by contact with an elemental oxygen-free atmosphere comprising hydrogen chloride at a temperature in the range of about 300°to 540°C. and a pressure of about 0.1-2 MPa for a time sufficient to saturate the catalyst with chloride; and (b) redispersing the metallic iridium and platinum while maintaining a saturated catalyst chloride level by contact with an atmosphere comprising elemental chlorine and elemental oxygen and water, in a chlorine to oxygen volume ratio of about 0.2 to 5, at a temperature in the range of about 500°to 540°C., and a pressure of about 0.1-2 MPa for a time sufficient to effect about a 75-100% redispersion of both metallic platinum and iridium.