New Technology for Pd Recovery from Selectively Leached Residue of Waste Palladium Catalyst
废催化剂选择法浸渣中提取钯新工艺

There is still 10~100 g/t Pd in the selectively leached residue of waste catalyst, and five factors are considered to probably cause the result: reabsorption, diffusion resistance in pores, hydrolysis, partial substitution, inclusion etc. Using weak alkaline leaching agent CN as an alternative was proposed and testified to be effective. By this technique, Pd content in 150 mesh milled residue was dropped from 51.6 g/t to 1.2 g/t. In a 100 t scale vat leaching test with granular materials, Pd was dropped to 3.0 g/t. The leaching recovery is respectively 97.7% and 94.2%. Pd in leaching solution was directly adsorbed with AC (active carbon) with high absorption rate and good selectivity. Pd loaded AC was burned in oxygen-rich fire, and above 99.95% purity of Pd powder was made by the amino-complexing method. This technology has the features of simple process, less facilities required, high metal recovery and high product purity etc.