Patent ID: 8163230
Filing Date: 2012-04-24
Classification: F27B,F27D

Abstract:
1. A rotary hearth furnace for treating metal oxide materials comprising: an annular enclosure having a roof and spaced apart inner and outer circular sidewalls; an annular hearth for supporting metal oxide materials to be treated, the hearth being mounted for rotary movement within the enclosure, the enclosure and the hearth being formed of a refractory material; one or more primary fuel burners positioned above the hearth, the burners having a discharge end positioned within the enclosure, the burners being capable of being fired to discharge combusted gases into the furnace, thereby heating the furnace walls, roof and hearth, whereby the furnace walls and roof are capable of radiating heat to the metal oxide materials on the hearth; and one or more oxygen nozzles positioned above the hearth, where the oxygen nozzles are connected to a supply of oxygen, the oxygen nozzles having a discharge end within the enclosure so that oxygen flowing from the nozzles combines with gases evolving from the metal oxide material, where the oxygen nozzles are positioned high enough above the hearth to avoid substantial contact between the oxygen and the metal oxide material, thereby creating a quiescent zone immediately above the metal oxide material, with the quiescent zone being sufficient to minimize entrainment of particulate matter from the metal oxide material.