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

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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.

著者

Akira SATO Goro ARAGANE Satoshi OGATA Kei YAMADA Shiro YOSHIMATSU

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.26, no.11, pp.949-954, 1986 (Released:2006-09-08)

参考文献数

14

被引用文献数

1

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The oxidation rates of the elements in molten pig iron weighing 1kg contained in a graphite or an alumina crucible were measured by adding Fe2O3, CaO, Na2CO3, BaO, BaCO3, and Li2CO3 onto the bath. The dissolution rate of B2O3 in slag in distilled water or HCl solution was estimated by adding 10g of slag into water or a solution of 300cm3, stirring for 30min, and filtering.Boron in pig iron was effectively oxidized and trapped in the slag by the addition of Fe2O3 containing high basic fluxes under a higher oxidation atmosphere at low temperatures. Recovery of B2O3 can effectively be made by the dissolution of slag in distilled water at 100°C and more efficiently in HCl solution above 0.25N at 50°C. The dissolution of B2O3 in water was interfered by MnO, FeO, and SiO2.

著者

AMATATSU Masayoshi STUTS Volker GUDENAU Heinrich Wilhelm

出版者

一般社団法人 日本鉄鋼協会

雑誌

Transactions of the Iron and Steel Institute of Japan

巻号頁・発行日

vol.25, no.9, pp.949-952, 1985

被引用文献数

6

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Evaporation of potassium from slag was investigated in order to estimate the effect of chemical composition and temperature. The evaporation rate increased with addition of basic oxide as FeO, CaO and MgO and it decreased with addition of amphoteric oxide such as alumina and titanium dioxide. Addition of MgO substituted by CaO under constant basicity B=(CaO+MgO)/SiO₂ affected positively the delayed evaporation of potassium oxide.

著者

Hiroshi G. KATAYAMA Ting TSAO Naoshi MATSUSHIMA

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.28, no.3, pp.186-191, 1988 (Released:2006-09-08)

参考文献数

20

被引用文献数

4 3 10

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Experiments were done on the distribution of each element between liquid Fe-Cr alloys and CaO-MgO-Al2O3-SiO2 slags having the compositions near the CaO-Al2O3 binary system in a magnesia crucible at temperatures of 1575, 1600 and 1650°C. The distribution ratios of chromium and sulphur, the oxygen content of liquid alloy and the activity coefficient of CrO in slag were expressed as functions of temperature and compositions of liquid alloy and slag. The major equations derived are as follows. log (wt%O)=0.413 log NCrO+0.0065 [wt%Cr] -0.091 ∑Ki•Ni-13044/T+5.574 log (wt%Cr)/[wt%Cr]=2.04 log [wt%O] -0.048 [wt%Cr]+0.292 ∑Ki•Ni+26 805/T-10.487 log γCrO=-0.561 log NCrO-0.096∑Ki•Ni -3044/T+1.528 log (wt%S)/[wt%S]=-0.47 log NCrO+0.0087 [wt%Cr] +2.835 ∑Ki•Ni+6902/T-4.28 where, ∑Ki•Ni=NCaO+0.1NMgO-0.8NAl2O3-NSiO2

著者

Yasunori NISHIKAWA Sogo SAYAMA Yoshinobu UEDA Yoshikazu SUZUKI

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.23, no.8, pp.639-645, 1983 (Released:2006-09-08)

参考文献数

13

被引用文献数

1 1

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The effect of K2O, Na2O and CaO on the reduction behavior of Fe2O3 was investigated. Platelets of Fe2O3 single crystals were prepared by the flux method. The size of the crystals was approx. 3mm in width and 0.3mm in thickness. For the reaction of Fe2O3 with K2O, Na2O, and CaO, small amounts of each carbonate powder were placed on the flat plane (0001) of Fe2O3 and heated at 1100-1300°C in the air. It was confirmed by EPMA that the reaction products with those substances were formed on some parts of the Fe2O3 crystal. The crystals were reduced at 750°C in CO and H2 streams, and the surface structures were observed by SEM.The results obtained were as follows. When alkaline metals (as Na2O, K2O) were present in Fe2O3, the abnormal swelling took place during the reduction. It was considered that the swelling was caused by (1) the cracking of the crystal at the early stage of the reduction, (2) the fibrous iron formation and (3) the carbon deposition on the reduced iron. The fibrous iron formation was also observed in the grain boundary of calcium ferrite. The reduction with a glassy slag (SiO2-Al2O2-CaO) was also investigated and no swelling phenomenon was shown.