Abstract: An absorbent for sulfur oxides comprising an inorganic oxide composition in association with at least one free or combined rare earth metal selected from the group consisting of lanthanum, cerium, praseodymium, samarium and dysprosium, wherein said inorganic oxide composition is selected from the group consisting of MgAl.sub.2 O.sub.4, mixtures of alumina with magnesium oxide and mixtures of magnesium oxide with MgAl.sub.2 O.sub.4. The absorbent can be circulated through a fluidized catalytic cracking process together with hydrocarbon cracking catalyst to reduce sulfur oxide emissions from the regeneration zone.