Patent ID: 6030432
Filing Date: 2000-02-29
Classification: C21B,Y02P

Abstract:
A process for the reduction of fine ore by reducing gas in the fluidized bed method, said process comprising:fractionating fine ore (2) by the aid of the reducing gas into at least one coarse-grain fraction and at least one fine-grain fraction;reducing each fraction by the reducing gas in a separate fluidized bed (3, 12), wherein the reducing gasmaintains a first fluidized bed (3) containing the coarse-grain fractions,fractionates the fine-grain fraction from the coarse grain fraction by accelerating the reducing gas together with the fine-grain fraction by contraction means (9), andsubsequently maintains a second fluidized bed (12), into which said reducing gas is continuously injected in a radially symmetrical manners;directly injecting a secondary reducing gas into the second fluidized bed (12) in a radially symmetrical manner in an amount and/or chemical composition to ensure reduction of the fine-grain fraction in said second fluidized bed (12); anddischarging reduced ore from both the first and the second fluidized beds (3, 12).