Patent ID: 6960238

Claim:
A fluidized-bed process for gas reduction of particulate iron oxide-containing ores, the process comprising the steps of: preheating, and also optionally pre-reducing the ore in the presence of a reducing gas produced from coal in a first fluidized-bed reactor designed as a pre-heating stage; then reducing the preheated ore to sponge iron in the presence of a reducing gas produced from coal in a reduction stage comprising at least one further fluidized-bed reactor; conducting reducing gas for the reduction step to the reduction stage via a first feed duct; conducting reducing gas for the preheating step from the reduction stage to the pre-heating stage via a second feed duct; maintaining the fluidized beds at a pressure of ≦5 bars, drawing off and purifying the reducing gas from the preheating stage as an export gas; heating the reducing gas fed to the reduction stage and/or pre-heating stage by combustion together with oxygen and/or air, of a quantity of combustible material; independently controlling the composition and/or temperature of the reducing gas provided to the fluidized-bed stages.