Much effort has recently been made, by a number of investigators, to analyse ventilation network problems by a digital computer. The authors have also carried out, for several years, the same investigation. As the result, they have obtained such a routine that may enable to find, in a minimum time, the rate of flow in any part of a ventilation network, no matter how complicated it may be, under the conditions that the specific resistances of the greater part of airways and the rates of flow of the remaining airways as well as the characteristics of fans are given.

View full abstract

It is supposed that the rate of convergence in roadway of the coal mine depends upon the several dynamical phenomena caused by driving the roadway. As a part of the study on outburst of gas and coals, the author has measured the rate of convergence in three roadways of Akabira coal mine. The results of measurement have revealed that the rate of convergence fluctuates as the face advances and that sometimes this rate coincides with the rate of gas outflow and sometimes not. The author assumes that the cause of the fluctuation in the rate of convergence may be in the unhomogeneousness of roof strata.

View full abstract

The wave property of wire rope is very important on manufacturing and using the wire rope for colliery and mining. Nevertheless the exact testing method for wave property has not been found as yet. in this study we invented the new testing method for the direction an degree on the wave of wire rope and named it KE test.
In this paper we explain the method and principle for KE test, give the example for testing the wave of wire rope and state the relation between form of wave and KE value.
We expect this method will be very useful for the maintenance of the wire rope forcolliery and mining.

View full abstract

The adsorption isotherms of dodecylammonium chloride on silica and labradorite at natural pH and for various pH values were determined using a radioactive form of the reagent. The effect of Ca ion and Na ion on the adsorption of dodecylammonium chloride on silica and labradorite was also investigated.
The results of adsorption tests of dodecylammonium chloride on both silica and labradorite indicated that there is a significant difference between both adsorption mechanisms. Namely, dodecylammonium ions adsorb at Stern layer on quartz surface as counter ions, on the other hand, dodecylammonium ions mainly adsorb on the labradorite surface by ion exchange, viz, by exchanging Na ions or Ca ions which are lattice cations of labradorite.
The effect of pH on the adsorption of dodecylammonium ion on both silica and labradorite showed a similar tendency, however, the mechanisms differ from each other. On silica surface, H ion is potential determining ion and so controls adsordtion of dodecylammonium ion as counter ion in the Stern Layer. On the other hand, since Na ion and Ca ion which are lattice cations of labradorite are exchanged easily by H ion in acldic side, H ion is a competitor to the dodecylammonium ion for labradorite surface.
The effect of Ca ion on the adsorption of dodecylammonium chloride on silica and labradorite was less than the effecf of H ion, but it was signmcant.

View full abstract

The characteristics of electrification are suggested by a behaviour of the grains in electric field. In static field, a precise separation to be hardly expected because of occurrence of those charges by friction, contact and dielectric effects against selective induction effect. Better result will be obtained under the ionized field, and the most efficient separation will be given by a combination of ionized and static field. The predominent feature of the combined field is mainly appreciated in respect that a charging and a discharging potential can be controlled widely by an adjustment of the electrodes. The paper comprises an outline of the charge for each, the selectivity for the separating conditions and an example of electrostatic separation under the combined field.

View full abstract

The extraction of nickel from the New Caledonian garnierite are with slufuric acid solution under pressurized oxygen atmosphere was studied:
(i) The oxygen increases the extraction of nickel in dilute acid leaching (less than 10% of sulfuric acid). It is about 5% higher than those in atmospheric air or nitrogen.
(ii) With increase of acid concentration, the effect of oxygen on nickel extraction decreases.
(iii) The oxygen also depresses the dissolution of iron into solution.
(iv) 60-86% of magnesia in the are was extracted into solution; it varies with the sulfuric acid concentration. The oxygen scarcely affects on the magnesia extraction.

View full abstract

Aqueous solution of aliphatic amine has a property to dissolve lead sulfates. With DETA, somm laboratory tests were tried to for the prepare high purity lead from lead concentrates, lead residues and copper anode slimes.
From these tests, it is obtained that:
(1) Lead in sulfate form can be extracted sufficiently with DETA
(2) Over-all loss of DETA is supposed to be less than 5% in one extracting cycle, including diminution of its extracting power.
Although DETA and other amines are so expensive at this stage as to use them in industrial scale, . it is expected in very near future that these amines with their lowered price can be used more widely in metallurgical extraction.

View full abstract