Process for recovering platinum group metals from deactivated catalyst

摘要

Platinum group metals are recovered from a deactivated catalyst containing the metal and fluoride on an alumina support by digesting the catalyst with sulphuric acid, preferably 90% to 110% of the stoichiometric equivalent of the alumina in the catalyst, to dissolve a major portion of the alumina, followed by digesting the remaining sludge with hot aqueous sulphuric acid of 15% to 80% weight concentration and separating the resulting fluoride containing solution to leave the platinum group metal. The first digestion is carried out above 38 DEG C. preferably at 120 DEG C. to 175 DEG C. with sulphuric acid of 20% to 90% concentration for 1 to 7 hours with agitation and the sludge is washed with hot water before the second digestion at 50 DEG C. to 175 DEG C. for 1 to 24 hours with agitation. The resulting platinum group metal sludge may be washed with water and then treated with aqua regia or washed with water and then dried.