Ultra fast microwave-assisted leaching for recovery of platinum from spent catalyst

The platinum/rhenium bimetallic catalyst is widely used in reforming process for the production of high octane fuels. This spent catalyst contains 0.2% Pt, 0.43% Re and other impurities. This work has investigated two alternative methods for leaching spent catalyst sample. In the first method the sample was refluxed with aqua regia at a liquid / solid ratio of 5 for 2.5 h. In the second case, microwave radiation was used at a power of 150 W with aqua regia at a liquid / solid ratio of 2 for 5 min. After leaching, the platinum was separated from rhenium and recovered as diammonium hexachloroplatinate with recoveries of 96.5% and 98.3%. Rhenium was recovered as potassium perrehenate by recovery of 94.2% and 98.9%, respectively in these methods.