The present paper examined the grain size and microstructures of the pyrite cinder powder as compared with the cinders of the size around 1cm and chemical formnlae of the copper compounds in the cinder.
From the result of experiment, it was found that the powder cinder scarcely bears the roasting nuclens and that the copper does not remain as chalcopyrite nor as bornite, but is present as CuSO₄, Cu₂S, Cu₂O, CuS.

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The Yawata Iron Works have intended to practise the pig-ore process in the 100ton open hearth furnace being supplemented with the mixer for preliminary smelting.
However, owing to shortage of the capacity of the mixer, they are partly obliged to practise the ordinary pig-ore process by using the open hearth furnace alone. The author explained the pig-ore process by the parallel use of an open hearth furnace and a mixer, citing the actual operations with special reference to the control of slags which is necessary for the open hearth furnace smelting. Moreover, the author described the actual operation of redressing the hearth which plays the important role in improving the efficiency of the pig ore process, some points of improvement in the body of the open hearth furnace developed since beginning and informed experiences and results of using the mixed gas as fuel.

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The author presented statistically results of the operation of the No. 5 basic open hearth using mixed gas in Showa Steel Works during the period from April 1937 to Sept. 1939. Then the author examined physical and chemical reactions that take place when mixed gas is preheated in the regenerator and gave useful directions concerning the practice and construction of the open hearth.

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(1) Direct deoxidation of molten steel by manganese was experimented, obtaining the following formula for the solubility of MnO, in which the sample had been skimmed from the molten steel with a specially designed quartz apparatus and quenched immediately in mercury, and the MnO and FeO in the steel had been analysed by the alcoholic iodine method:-
Solubility of MnO (%)=1·5×10-4t°-0·198. For instance about 0·05% MnO dissoives at 1650°C and the following deoxidation equilibr%ium:
[FeO] in steel+[Mn] [Fe]+[MnO] in steel.
(2) In case where silicon was added to the molten steel, an acidic SiO₂ cvolves, absorbs MnO and floats off. Therefore the abovementioned equillbrium disjoins, causing the reaction to the right alone. In other words, in case of the coexistence of silicon even the small quantity of the manganese content participates in deoxidation, being effective to the elimination of SiO₂. In practice, a sample was taken with a vacuum sampling vessel from the mollen steel at the deoxidation period in the acid open hparth refining, the analysis of which yield an extremely slight quantity of SiO₂ as the deoxidation product.
(3) A considerable amount of Fe-Si or Si-Mn was added to about 2kg of the molten steel with 0·2% Mn and solidified within some minutes. From the results of a number of such experiments, it was found that steels with above 0·35% Si contain below half amount of the silicate inclusion when compared with those with about 0·20% Si. Similar results were obtained in the melting teat on a larger scale.
(4) It is presnmed therefore that, the deoxidation degree of the molten steel may be improved and the silicate inclusion of ingots may be lessened by suitably utilizing the method of adding considerable amount of silicon to the molten steel with above 0·2% Mn.

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Teil I. Wir haben die Gleichgewichtkonstante der Reaktion
FeS+H₂ Fe+H2S
bei 700°, 800°, 856°, 900° und 1000°C nach der kinetischen Methode bestimmt. Sie werden durch die Gleichung K=PH2S/PH2 gekennzeichnet. Das Ergebnis wird nach der folgenden Gleichung dargestellt.
lo K=-3, 910·285/T+0·887
Diese Werten stimmen eindeutig mit der von Sano gefundenen ein Im Zusammenhang mit der Dissoziationskonstant des Schwefelwasserstoff berechneten wir die Dissoziationsspannung des Eisensulfid.
Teil II. Gemisch des Wasserstoff und Schwefelwasserstoff von gewisse Zusammensetzung wird uber das flussige Elsen geleitet und nach dem vollkommenen Reagieren wird das Schwefelgehalt des Eisen (nach der Erstarrung) und des Abgase bestimmt. Die Gleichgewichtkonstante der Reaktion FeS(in Fe)+H Fe(flussig)+H₂S
wird durch die Gleichung K=PH2S/PH₂·[FeS]gekennzeichnet; des Ergebnis wird wie folgend darge-
stellt:
logK=-4, 427/T-0·326
Nach der oben gegebenem Werte haben wir Rech ung mit der Bildungs reaktion des Eisensulfid in flussigen Eisen und der Entschwefelungsreaktionen durch Kohlenstoff, Eisenoxydul und Kalk gemacht.

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Physikalisch-chemische Natur der Schlacken: Quantitative Zusammenhänge zwischen den Konzentrationen der "freien" Komponenten und der Gesamtzusammensetzung der Schlacke. S. 32-44.

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