Method of measuring the reducing power of gases over the charge in a blast furnace

The reducing power of gases liberated at the top of the charge of an industrial furnace is determined by a method wherein the energy radiated from the charge in the range, for example between 1 and 6 microns, covering the radiant energy emitted by the compounds CO2, CO, H2, and CH4 is continuously measured in a multiplicity of detection points distributed over the entire upper surface of the charge and outputs are formed corresponding to the energy radiated at each of the points. An energy image of the energy radiated at the points in the range is formed from the outputs. This energy image is converted into respective specific images for the compounds by isolating from the energy image for each detection point the radiant energy emitted by the compounds. The concentration of each of the compounds at each of the points is calculated from the intensity of the respective specific image. Finally the reducing power at each of the detection points is derived from the respective concentrations of the compounds thereat.