- 著者
- Ko-ichiro Ohno Yoshiki Kitamura Sohei Sukenaga Sungo Natsui Takayuki Maeda Kazuya Kunitomo
- 出版者
- The Iron and Steel Institute of Japan
- 雑誌
- ISIJ International (ISSN:09151559)
- 巻号頁・発行日
- vol.60, no.7, pp.1512-1519, 2020-07-15 (Released:2020-07-16)
- 参考文献数
- 11
- 被引用文献数
- 5 8
Negative effect from low coke rate operation at cohesive zone is obvious because it makes thinning of coke slit thickness. Correct knowledge about gas permeability of cohesive layer is becoming more and more important. In order to precisely understand cohesive behaviour, a softening and melting simulator under rapid heating and quenching conditions was applied for clarify a determinant factor of gas permeability behaviour. To focus on softening and melting behaviour, granulated slag particle bed layer without iron oxide was prepared as packed bed sample layer can show softening and melting. The packed bed slag samples in graphite crucible were rapidly heated up to 1200°C, and then gradually heated up to 1500°C with 10°C/min under inert gas atmosphere and 0.1 MPa load. Gas pressure drop and shrinkage degree of the sample layer were measured during the softening and melting test, and quenched sample was made at certain temperature when the maximum gas pressure drop was measured. The CT observation of the quenched sample provided 3D shape information of gas path shape in sample packed bed. Gas pressure drop was estimated with fanning’s equation with the gas path information. The estimation values were shown positive correlation with measured maximum pressure drop. The CT observation also gave triple line length among molten slag, graphite, and gas. Combination the triple line length and molten slag surface tension could use for evaluation of static force balance when maximum pressure drop obtained.
- 著者
- Takayuki MAEDA Yoichi ONO
- 出版者
- The Iron and Steel Institute of Japan
- 雑誌
- Transactions of the Iron and Steel Institute of Japan (ISSN:00211583)
- 巻号頁・発行日
- vol.25, no.12, pp.1191-1193, 1985 (Released:2006-09-08)
- 参考文献数
- 2
- 被引用文献数
- 17 18
The reduction behavior of constituent minerals of iron ore sinter has been investigated microscopically by using two kinds of commercial sinter having different basicity and FeO content. The results are summarized as follows:(1) There is a difference in reducibility between hematite and magnetite, and hematite is reduced faster than magnetite.(i) Both hematite and magnetite are reduced rapidly to wustite, but there is a difference in the rate of reduction from wustite to iron.(ii) The reduction of wustite reduced from hematite does not proceed topochemically but homogeneously. Although the reduction of the wustite is comparatively fast in the almost whole period of reduction, part of the wustite becomes surrounded by dense iron and left unreduced in the final stage of reduction.(iii) In the reduction of wustite reduced from magnetite, almost all grains of wustite are surrounded by dense iron from the early stage of reduction, which causes the retardation of reduction.(2) Calcium ferrite is reduced much faster than the wustites mentioned above, which is shown by the fact that many grains of wustite are left unreduced even after calcium ferrite is reduced completely.(i) The reduction of calcium ferrite proceeds topochemically.(ii) Iron produced by the reduction of calcium ferrite is very porous and not sintered, which does not cause the retardation of reduction.(3) In many cases, reduction begins with the surface of mineral grains facing a macro-pore, which serves as a passage of reducing gas to each mineral grain to be reduced.