The authors studied on the flotation concentration of the low grade iron ore (30-38% Fe) from near Anshan, Manchoukuo by using the M.S. 500g testing machine, and gave experimentally a clear solution for this problem.
In this research the following results were obtained.
1. The fatty acids composed mainly of linolenic acid, which had been obtained from drying or semidrying vegetable oils such as poppy sead oil, soya bean oil, showed so strong collecting power for the iron ore that these may be used as good flotation reagents. By using the unsaturated fatty acids, which had been separated from the above-mentioned vegetable oils, or the mixture of the fatty acids and high temperature tar, the authors su ceeded in flotation experiment even for the low pulp temperature between 2 and 10°C.
2. The most preferable conditions for flotation were as follows: soda ash 800-1000g/t, fatty acid 200g/t, pulp density··roughing 30-35%, cleaning 20-25%, peripheral speed of impellor 150-300m/sec, grinding 150mesh, flotation time··rou hing 10min, cleaning 4min.
3. By roughing 10min and successively cleaning 4min under above-mentioned conditions, the authors obtained the following results for the 36% Fe ore: concentrates with 60% Fe, tailings with 10% Fe, iron recovery 85%.

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The quality of silica bricks depends mostly on the properties of materia's used Heretofore an excellent material, the so-called "akasiro Keiseki" (red-white silica) has been used in Nippon. Owing, however, to the recent abrupt development of the steel manufacturing industry, the production has been unable to keep pace with the incre sed demand, and excellent red-white silica deposits are found to be less and less. Some fear for the future of silica bricks has occurred and conslderation of counter measures devised everywhere. The present report dealt with properties, production amount and merits or demerits of different kinds of silica materials which are used now and in future. Then the author explained the superiority of the red-white silica as the silica brick material for steel making furnaces, referring to the present status of investigation on the manufacture of silica bricks for steel-making furnaces from silica materials other than the red-white silica. Lastly the author discussed prospects and counter measures for the silica material from the viewpo nt of silica brick manufacturers.

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1) The carbon absorption by Mn-Si, Fe-Si, Mn-Fe and Mn-Fe-Si alloys had been investigated, and the results were summarized as follows:
The carbon absorption by liquid Mn-Si alloys increases progressively from practically nil at about 30% Si to a high value as the silicon content decreases. It also increases with the rise of the absorption temperature. The speed of the absorption is such that the alloys are saturated with carbon relatively in a short time.
The carbon absorption by the liquid Fe-Si alloys decreases with the increase of silicon and becomes insignificant when this element in the alloy exceeds 20%.
The carbon absorption by the liquid Mn-Fe alloys is considerable on the manganese side but gradually decreases with the increase of the iron content. In the Mn-Fe-Si alloys, the higher the manganese content the more the carbon absorption, provided the silicon content remaining constant.
2) The reaction between Mn-Si alloys and MnO-SiO₂ and MnO-CaO-SiO₂ slags had been studied and the results were summarized as follows:
The reaction between the alloys and the slags proceeds slowly so the reduction of MnO by Si increases with the time. Higher temperature favors the reaction between them.
The alloy-slag ratio that yields the maximum reduction of MnO varies with the acidity of the slag. An addition of CaO to the MnO-SiO₂ slag promotes the reaction between the alloys and the slags.

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The direct method of producing iron and steel was introduced, in which the iron ores, especially powdered hematite or magnetite mixed with carbon, were reduced in a long, shallow electric furnace by means of low or high frequency alternate current at high voltage.
Thiss method has been already known as "KOSYUHA DENGEKI Method" and is supposed to the superior to the other kinds of smeltings in the following points:
1. The iron ore charged in the furnace was reduced in a short interval of about 8-15min., supplying high voltage source to the ends of the furnace, and therefore the impurities included in the steel thus made is perhaps very little.
2. The powdered ores, especially powdered magnetite are more suitable for this method.
3. The reduced aggromelates are taken off from the furnace as soon as the reduction is over, and the other unreduced mixture lies still in the furnace which awaits for the next similar process. Thus the mixture protect the fumace from the thermal corrosion.
In the present paper the theoretical investigation of the aforementioned method was first reported from the aspect of chemical metallurgy.
As any other basic oxides were not added, the reaction was usually operated in the presence of an acidic slag (MnO-SiO-FeO system) and therefore phosphorous and sulphur contents of the raw iron were rather high (0·1-0·37% each).
For the purpose of slag formation, other basic oxides as CaO, MnO were added, and (KMn), and reaction temperature were calculated according to the Körber and Olsen's formula of acidic slag.

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The author's investigation was to cover the permeability, heat conductivity and other properties of the foundry sand, of which the present study concerned the permeability. It was presumed in the investigation that the sand layer consists of an aggregates of capillaries and each capillary is of the same diameter. (1) The diameter, (2) the length and the distributive density of the capillary were taken as the inner-structure constants of the sand layer. The author dealt with the method of determining the three constants and measured experimentally the inner-structure constants relating to each of sand layers discriminated by passing through a sieve and the binary layer of their systematic mixtures. Besides, the author measured the acral permeability through each of the sand layers. comparatively studied on its relation to the inner-structure constant and referred to the permeability of an aggregate of the "perfect globules."

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The authors investigated some important industrial properties of a series of Fe-CrAl alloys containing 5-30% Cr and 1-7% Al, such as hardness. specific resistance, its temperature coefficient, oxidation resistance, specific weight, thermal expansion and magnetic transformation.
The authors, again, examined effect of grain growth on mechanical properties, since the alloys have unusual phenomenon of grain growth at high temperatures. The result of experiments was summarised as follows:
In the hardness test, it was found that the most suitable heat treatment for softening these alloys is heating to about 800°C followed by rapid cooling. From the result of measuring the specific resistance, the ternary specific isoresistance curves were completely plotted, In the oxidation test, in case the Al content is in excess of 3%, the 15% Cr addition is sufficient for enhancing high temperature oxidation resistance but further addition yields little improvement. Besides, in Fe-Cr-Al alloys with the high-Cr and high-Al content, a remarkable grain growth is observed by heating to temperatures above 900°C and they become very brittle. Therefore full consideration should be made in annealing or using them at high temperatures.

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