Patent ID: 6641392
Filing Date: 2003-11-04
Classification: C22B

Abstract:
A method for regulating roasting furnace conditions in a roasting furnace having a fluidized bed in which a material for roasting is calcined, comprising feeding the material for roasting into the furnace at a location above the fluidized bed, feeding a fluidizing roasting gas through nozzles within a main grate located at the bottom of the furnace to fluidize the material for roasting, removing from the furnace at least some of the calcined material through an overflow aperture located at the top of the fluidized bed, separating off part of the roasting furnace main grate, within the same section of the furnace that the overflow aperture is located and below the overflow aperture, to form a separate section, an overflow grate, and feeding fluidizing roasting gas through nozzles within the overflow grate at a rate that is independent of the rate that fluidizing roasting gas is fed though the nozzles within the main grate.