Reduction of Sintered Ore in Fixed Bed with CO Gas
1974 Volume 60 Issue 10 Pages 1425-1431
Details
1974 Volume 60 Issue 10 Pages 1425-1431
The reduction processes of sintered ore in the fixed bed with CO gas have been studied.
The reduction rates of sintered ore in the temperature range from 800 to 1000℃ have been measured by analysing the waste gas composition or by weighing the bed weight continuously ; the following results are obtained.
(1) The reduction curves obtained by gas analysis are in good agreement with those by the thermobalance in the same experimental conditions.
(2) At a constant ratio of the bed weight to the gas flow rate (M/V), the same reduction curves were obtained at different gas flow rates (4.6, 9.1 and 36 Nl/min) ; the gas film resistance seems to be unimportant.
(3) The analysis based on the unreacted core model for a single pellet applied to the reduction of sintered ore with CO gas gives the following expression for the calculated chemical reaction rate constant ks=exp(5.23-14000/RT). As the calculated constant F defind as r0ks/De is dependent of the diameter of sintered ore, it is considered that the reduction process is controlled by the chemical reaction rate for small sizes (Dp=3 mm), but is controlled by mixed rates of the chemical reaction and the gas diffusion through ash layer for large sizes (Dp=7-13 mm).
