Die Aufbereitnng von kieselsäure und silikathaltigen Eisenerzen erfolgt allgemein dadurch, dass man die Erze nach dem Zerkleinerung durch den Magnetscheider laufen lässt, um zu dem gewünschten Konzentrat zu gelangen.
Das Konzentrat, das man bei diesen Verfabren auf den Showa Stahlwerken erhält, lässt noch zu wünschen übrig, weil es noch ungefähr bis zu 20 v. H SiO₂ bei 58 v. H Fe hat. Den SiO₂-gehalt unter 15 v. H zu bringen, ist der natürlicben Eigenschaften des Erzes wegen sehr schwierig. Wir versuchten in unserem Laboratorium durch ein Nassverfahren ein besseres Konzentrat dadurch zu erhalten, indem wir die Erze mit Alkali lösten.
Das Verfahren ist im Prinzip sehr einfach:
2SiO₂+2NaOH=Na₂O 2SiO₂+OH₂
Schon bei wenigen atmosphaeren Druck wird nicht nur die feinverteilte Kieselsaure vollständig gelöst, sondern auch grössere Anhäufungen von kieselsäure in kompacter Form wurden durch die genannten Verfahren im Alkalisilikat übergefuhrt. Zweltens bezwerkt das Verfabren den Alkaliverlust völlig zu beheben und zwar durch Regenerierung der Alkalien zu Hydroxyd, um zur Erzeugung unloslicher Kieselsaüre oder silikate zu gelangen, die vielseitige Verwendungsmöglichkeit besitzen Z. β beider Cementhellstellung, Glasfabrikation, Herstellung von Bindemitteln für Brikettierungszwecke u. s. w.

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Recently, it has been accomplished to manufacture low silicon pig iron for basic open hearth furnace by blast furnace in Japan. And so the next important problem on this line is turned to reduce further its carbon content as possible, because in our country, for want of steel scrap, the open hearth furnace works in future have to be operated mainly with pig iron and ore for their materials, and it is necessary to reduce carbon content of molten pig iron-the chief materials of the above operation-as low as possible.
At the beginning of this study the author discussed on the equilibrium relation between iron and carbon at high temperature as in blast furnace; and then explained theoretically in details on the course of carbon absorption into iron during the charge traveled from top to bottom of the furnace with many data; and also stated on the influence of other elements upon the absorption of carbon into iron. Then the author studied closely on melting zone of blast furnace to find that the socalled concentrated melting method should be adopted for blast furnace operation in future, that is the total thickness of melting zone should be kept possibly thin but width and thickness of the highest temperature oxidized part in it must be enlarged and brought below in hearth as possible. And when the combution in furnace is rationalized by the further study of tuyres, and also adequate forehearth is established, this problem will be solved to a certain extent.
Finally the author explains that he has now constructing a large experimental blast furnace for this object, and soon will begin the study witn it to solve this interesting and important problem.

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Utilizing the Magnetic analysis with specimens of less than 27.8% Cr and 1.55% C, the change of the transformation point due to the cooling conditions was studied, and several diagrams showing the composition range in which the transformation is lowered and its change due to the cooling conditions were proposed. The microstructure of these specimens and its change due to the cooling conditions were examined, and structural diagrams showing the relation between the composition of specimens and the microstructures in 4 cases cooled from 900° and 1, 100° in furnace and in air, respectively were constructed. Based on these diagrams the effects of carbon and chromium contents in specimens, the cooling rate and the maximum heating temperature on the microstructure were elucidated. By examining the microstructure of several specimens which were carburized and cooled under several conditions the effect of carbon on the microstructure was studied, and the correctness of the structural diagrams obtained above was confirmed.

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