In this paper, the recent development of acid smelting of the blast furnace is discussed. The working results wi'h acid slag at the Corby Works in England and the Gutehoffnungshütte in Germany are briefly described.
In the Corby works, it has been previously very difficult to smelt Northamptonshire ore for the manufacture of basic pig iron for steel making purposes, on account of the high proportion of alumina to silica. The difficulties encountered with high alumina slag has been successfully overcome with the basicity ratio of about 0·93 in the slag, which is the ratio of lime to silica for obtaining a minimum melting point and a minimum viscosity.
In the Gutehoffnungshütte, the idea is to reduce the amount of slag produced and the quantity of coke consumed in the smelting of low grade German ore for the production of basic bessemer pig iron with acid slag which has the basicity ratio 0·8.
It is an unsuitable and inefficient method for the elimination of sulphur, and no attenti on is paid to the sulphur content of the pig iron. The sulphur is removed by subsequent treatment with soda.

View full abstract

Flotation process was carried out for the removal of P in iron ore. In this paper are dealt with the effects of various reagents, such as sodium palmitate, sodium silicate, sodium carbonate, lime and pine oil, upon the floatability of apatite in iron ore.

View full abstract

The author found a new fact that iron ore expands due to the reduction by H₂ or CO. After having cosidered the various results of the present experiments, the author reached the conclusion that when iron ore is reduced by H₂ or CO, the reduction product H₂O or CO₂ accumulates in isolated cavibies in the ore, their pressures increasing to overcome the breaking strength of the iron ore as the reduction proceeds.

View full abstract

Quick malleable cast irons, containing 1·2-25% of silicon, w re investigated.
In irons of a high silicon content, the time required for the first stage of graphitization is very short. Generally it was less than one hour. The limit of carbon and silicon contents, in which cast iron can be converted perfectly white, was investigated at several cooling rates.
Test pieces for the mechanical tests were taken from centrifugally cast cylinders, which were cast in a metal mould and annealed for the first stage of graphitization.
The lower the cabon and silicon con ents are, the higher the tensile strength of quick malleable cast iron. A strength of 60kg/mmmm² was obtained. The impact resistance of quick malleable cast iron depends on the silicon content and the structure of the temper carbon. Irons of a low silicon content show the better impact resistance.
Rings of quick malleable cast iron were tested for compression. Some of them can yeild to 1/3 of the original ring diameter before they break.
The author suggests the application of quick malleable cast iron to centrifugally cast iron pipes.

View full abstract

Using various aluminium ingots produced from Manchurian alumina-shales, the super-duralumin plates of 24S type were prepared and their mechan cal properties have been examined. The purities of the aluminium ingots used were 99·53%, 99·62% and 99·69%, respectively. For a comparison, the imported aluminium ingots of 99·57% was also used.
From the results of the experiments, it was confirmed that the mechanical properties of the duralumin plates made from the Manchurin aluminium is superior to those produced from the imported aluminium ingots.

View full abstract