Assessment of Palladium Recovery from Spent Pd-Al2O3 Catalyst: Comparative Analysis Using Copper and Iron Metal Smelting Methods

Spent Pd-Al2O3 catalyst was recovered by the metal smelting method. Cu and Fe were used as collector metals, and the capture process, smelting slag, and Pd-bearing alloy were comprehensively compared. The process condition results show that although the recovery rate of palladium of both capture processes is > 99%, the collection time using Fe smelting method is longer than that using Cu collection. The Si and P contents in Pd-bearing alloy under 1550 degrees C obtained by Fe collection are obviously higher than those by Cu collection, which causes the difficulty in separation of Pd from impurities. The cost of Fe smelting process is much lower than that of Cu smelting process, while the metal Cu alloy can be further reused through subsequent electrolysis separation. Therefore, Cu collection is suggested to be a better collection metal due to the shorter smelting time, possible lower impurity content under higher temperature and more favorable subsequent treatment process.