Fire recovery
Typically pyro-recovery of automotive exhaust catalysts involves the smelting of ceramic supports simultaneously with the enrichment of precious metals in metal collectors. The carrier, which forms slag without losing precious metals, is critical to the process.
The excessively high melting point of the alumina particles (about 2000°C) is a big problem. Therefore, this kind of material can only be slag by adding flux or taking extremely high melting temperature. Copper, nickel, lead and iron are generally considered as possible collectors for platinum group metals. The selection is based on the ease of processing and subsequent wet chemical stages. Precious metals—platinum, palladium, rhodium—are separated from metal collectors by sulfuric acid leaching. If copper is used as the collector, it can also be separated by electrolysis. Compared with the hydrometallurgical regeneration of spent auto catalysts, the advantages of the pyro process are much greater:
● The concentration of enrichment in the metal phase is high;
● High recovery rate of precious metals;
● It can be regenerated in the furnace types (blast furnace, converter) or special devices (such as electric furnace) commonly used for non-ferrous metals;
● The output of by-products or residues is small.