焼結鉱の還元時における粉化現象について

抄録

The results of several experiments on the degradation of sintered ores during reduction are summarized as follows:
(1) The initiation of cracks takes place, when the reduction of hematite commences.
(2) Degradation does not occurs if hematite has been converted to magnetite by the previous heat treatment.
(3) If the converted magnetite are re-oxidized to hematite, the degradation appears again.
(4) The changes of mineral phases during reduction are as follows:
a) The original hematite was quickly converted to co-existent phase of hematite and magnetite.
b) Accicular calcium-ferrites were coagulated during reduction.
c) The original magnetite crystals were broken down.
(5) The influences of reducing conditions can be summerized as follows:
a) The degradation did not proceed further after 90min.
b) The higher the CO content of reducing gas, the greater the degradation.
Based on these results, the sequence of degradation of sintered one is discussed.
The stress which initiates the cracks is considered to be generated from the quick alteration of mineral phases and shape of iron-oxides.