US 4,428,768 AGranted

Process for the recovery of platinum group metals from refractory ceramic substrates

AssigneeJohnson Matthey PLC

InventorJoseph G. Day

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Abstract

A process for recovery of platinum group metals (PGMs) from refractory ceramic substrates containing an aluminium silicate and/or alumina, for example, wash-coated auto emission control catalysts and Pt reforming catalysts. A charge, in divided form, containing the substrate, one or fluxes and a collector is heated in a high heat intensity furnace, to a temperature of at least 1420.degree. C. to produce a molten metallic phase including a substantial proportion of the said metals and a molten slag phase. These are then separated and the platinum group metals subsequently extracted from the metallic phase. By choice of suitable fluxes, at least some alumina can be converted to an aluminium silicate which becomes molten at the operating temperature. Further, the ability to use high temperature fluxes avoids the need for an excessive slag which is normally required to dissolve the high alumina content of such catalysts and which normally gives rise to unacceptable losses of the metals to be recovered when applying conventional pyrometallurgical techniques.

Claims17

Dependent claims

A process for the recovery of platinum group metals present in a used auto emission control catalyst comprising a refractory ceramic substrate having the platinum group metal deposited on or contained in the refractory ceramic substrate, the said substrate containing an aluminum-silicate and/or alumina, said process comprising preparing, in divided form, a charge containing the refractory ceramic substrate bearing the said metals, one or more fluxes, and a collector material or collector material precursor, for the metal or metals to be recovered, feeding said charge into a high intensity plasma arc furnace and heating the charge to a temperature in the range 1500.degree.-1750.degree. C. by means of the high intensity plasma arc of said furnace to produce a molten metallic phase containing a substantial proportion of the said metal or metals formerly deposited on or contained in the substrate, and a molten slag phase containing flux, ceramic residues and the remainder of the said metals, separating the two phases, and separating the platinum group metals from the metallic phase, the collector material comprising iron powder or filings, iron sponge or cast iron shavings.

Dependencies are inferred from the claim text.