強攪拌浴におけるクロム鉱石ペレットの溶融還元反応

概要

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Reduction behavior of partially reduced chrome ore pellet and other types of chrome ore pellet in a stirred bath was investigated by two experiments, the first one being a 70 kg scale one for fundamental understanding and the second one with 550 kg scale top and bottom blowing converter. (1) The change of total chromium content in slag, (T. Cr) is expressed by the combination of the rate equation of the zeroth order and that of first order. (2) Dissolved chromium content was estimated from analysis of state of chromium existence in slag. The change of (T. Cr) is expressed through all the region by following equation : -d(T. Cr)/dt=K・(Dissolved chromium content in slag) (3) When the value of (% MgO)+(% Al_2O_3) is higher than 45% at 1600℃, solution of chrome ore is disturbed by the formation of MgO・Al_2O_3 phase around chrome spinel. (4) Slag foaming is prevented by sufficient amount of coke (coke/slag≥10wt%) in top and bottom blowing converter. (5) Soft blowing of oxygen, and sufficient amount of slag and coke enable the compatibility of high combustion ratio (CO_2/(CO+CO_2) : Max.>0.8) of atmosphere and low chromium content in slag ((T. Cr) : 0.2-0.4%). It is possible to promote stably the smelting reduction of chrome ore or pre-treated materials in top and bottom blowing converter, by utilizing the large amount of slag formed.
社団法人日本鉄鋼協会の論文
1988-04-01