Metal Vapor Treatment for Enhancing the Dissolution of Platinum Group Metals from Automotive Catalyst Scrap

摘要

A new process for dissolving platinum group metals (PGMs) from automotive catalyst scrap using metal vapor was proposed. To improve the PGMs dissolution ratio from scraps, vapor of reactive metals (R), such as magnesium (Mg) or calcium (Ca), was reacted with the automotive catalyst scrap in a closed stainless steel vessel at 1173 K for 3 hours. Under these experimental conditions, Mg and Ca vapor was supplied to the entire body of catalyst scrap. After the reactive metal treatment, the specimens were crushed and dissolved in aqua regia at 323 to 333 K for 1 hour. The PGMs dissolution ratios were improved after the reactive metal treatment, and the dissolution ratios reached 88 pet in Pt, 81 pet in Pd, and 72 pet in Rh, while they were 77 pet in Pt, 69 pet in Pd, and 38 pet in Rh without the treatment. Even when the specimens were dissolved in aqua regia without heating, the PGMs dissolution ratios from the catalyst scrap after reactive metal treatment showed high values, 78 pet in Pt, 74 pet in Pd, and 57 pet in Rh at a maximum. These results show that the reactive metal treatment is effective for the recovery of PGMs from automotive catalyst scrap.