STUDY ON THE BLAST FURNACE REACTION BY RAPID COOLING OF BURDENS
Nobuo Nakamura, Yutaka Sato
In the past decade, the authors have investigated on the low shaft furnace with an oval section which had a capacity of up to 10 tons per day. The charcoal pig iron produced by the furnace has been used as one of raw-materials for special steel. During the investigation the authors constructed some of pelletizing pilot plants and an experimental low shaft furnace with the same section as abovementioned. This furnace had a capacity of 0.6m3 corresponding to one ton per day pig iron.
This report dealt with three times studies in regard to rapid cooling of burdens in other various experimental operations carried out with this pilot plant. The results obtained by our investigations were summarized as follows.
(1) To correct the positions of the burdens after cooling was very important, because some effects of their shrinkages during N2 gas blowing were observed especially at upper parts of the shaft.
(2) Segregation of the burdens was not found, while partial draft and super-heating was observed when a side tuyere had been one-sided.
(3) Change of pellets shape began at the lower half of the bosh, and slag-formation and separation were observed.
(4) Strength of charged pellet was weakened once at the halfway of the shaft, but the refractoriness of the pellet under load rised in proportion to increase of the degree of reduction of the pellt.