Results are reported of a study of the reactions occurringin the combustion of chaIcopyrite particles underconditions simulating those in the shaft of a flashsmelter.The reactions were studied using kinetic and mineralogicaltechniques. Reactions. rates above 500C wererapid, most of the reaction taking place in less than 50ms. Final products were copper-iron ferrites with spineltype structures. Probable reaction mechanisms are discussed.