PURPOSE: To reduce an ore having grain size distribution from fine grains to coarse grains in high efficiency at the same time.
CONSTITUTION: By making the diameter of the upper part 1a of a riser larger than the diameter of the lower part 1b of the riser, flow speed of reducing gas introduced from a reducing gas introducing part 3 is lowered at the upper part 1a. By this method, the fine grains discharged into a grain collecting device 4 from the upper part 1a of the riser are decreased and retention time in the riser 1 is extended. The fine reducing ores are discharged from a discharging hole 6 and originally the coarse grains having a long retention time are discharged from a discharging hole 7 to balance the reduction of the fine grains and the coarse grains.
ITAYA HIROSHI
SATO KAZUHIKO
| JPS62230910A | 1987-10-09 | |||
| JPH0238454B2 | 1990-08-30 |