BEHAVIOR OF FINES IN THE BLAST-FURNACE

Using a half section three-dimensional model of a blast furnace, a tuyere-injection experiment of coke fines was conducted. The following findings were obtained from the analysis of the influence of the injection rate and particle size of the fines on the burden descent and gas permeability and the study of the circulation and deposit behaviors of the fines in the blast furnace. With an increase in the injection rate of fines, the frequency of slips, the gas pressure, and the frequency and extent of the raceway shape variation increased. But the influence of the fines injection was limited when their particle size was much smaller than the size of the charged materials. The injected fines are to be deposited at the surface of the dead-man and near the furnace wall where the burden descent velocity is low. When the high-concentration regions of fines are formed at the surface of the dead-man and near the furnace wall, the burden descent region in the lower part of the furnace reduced and the retention time of the burden decreased. With the V-shaped stock and inadequate central gas flow, fines are likely to be deposited in the center and they descend with the burden.