Verfahren und Einrichtung zum Reduktionsroesten feinverteilter nickelhaltiger Laterit- und Garnieriterze

Ore is fed into the top of a multiple hearth furnace and, as it travels downwardly through the furnace, it is reduction roasted by means of a rising stream of hot reducing gases. Fine ore particles picked up by the combustion gases within the furnace and exiting therewith are removed from the gases and reinjected into the furnace at a point at which the degree of reduction of the particles approximates the degree of reduction of the ore which passes downwardly at the point. To prevent the injected particles from being carried upwardly by the partial combustion gases, the particles are injected in the form of a continuous plug.