All issues
Successor
Volume 56, Issue 657
Displaying 1-4 of 4 articles from this issue
- |<
- <
- 1
- >
- >|
-
Kenzo IKEDA1940 Volume 56 Issue 657 Pages 1-6
Published: January 22, 1940
Released on J-STAGE: July 13, 2011
JOURNAL FREE ACCESSWar particularly wants man, money and material. In this paper, it is heartily enforced on the urgent demand of the sufficient supply of metals as well as the allied power of the real men for the rising aggregated Nippon.View full abstractDownload PDF (1495K) -
Mituo KAMEDA1940 Volume 56 Issue 657 Pages 7-21
Published: January 22, 1940
Released on J-STAGE: July 13, 2011
JOURNAL FREE ACCESSThe writer studied the rate of dissolution of pure gold, in the form of plate, in potassium cyanide solution under the agitation of air, and got the following results.
1. The calculation of order of reaction, the effect of temperature, that of rate of agitation, that of viscosity of solution, and that of variation of atmosphere were studied, and he draws the conclusion that the dissolution of gold in cyanide solution follows the Centnerswer's theory rather than the Nernst's diffusion theory in the heterogeneous system.
2. Experimentally the maximum rate of dissolution is obtained at 0.030% KCN solution and mathematically it was 0.024% under the suggestion that both cyanide and oxygen molecules must reach at the gold surface by diffusion in the ratio called for by Elsner's equation at the best condition.
3. In many cases, the rate of dissolution decreases at the bigining and increases rapidly after 6-8 hrs, when the rate of dissolution is twice as fast as that at the bigining. This fact seems to show that OH ions may affect on the velocity of dissolution. When a small quantity of KOH or Ca (OH) 2 is added in cyanide solution at first. the rate of dissolution reaches maximum at pH. 10.35 and then decreases as the alkali content increases. This effect would be analogous to that the rate of decomposition of H2O2 at the surface of gold plate passes through a maximum at pH. 12.0. But the rapid drop of dissolution by the addition of Ca (OH) 2 is not yet explained.View full abstractDownload PDF (2618K) -
Kitiro YAMAGUTI1940 Volume 56 Issue 657 Pages 22-32
Published: January 22, 1940
Released on J-STAGE: July 13, 2011
JOURNAL FREE ACCESSIn this part of the reports the author described the features of the ore treatment in Sweden. Two representative mills were explained; one is the Gold-Silver-Copper-Arsenic-Sulphur mill at Rönnskär on the coast of Bothnia Bay, and the other is the iron concentrator at Grängesberg in Middle Sweden.
The Rönnskär mill treats the auriferous sulphide ores from the Boliden mine. The Boliden ore body was found in 1924 after several years' investigation by the geoelectrical surveying. The mill and smelter at Rönnskär are entirely modern. The production from the various units of the plants during the year 1936 was as follows:-
Gold 5, 102 kg, Silver 18, 298 kg, Copper 6, 746 t, Sulphur 19, 616 t, Pyrite concentrate 38, 090 t and Arsenious acid more than 30, 000 t (exact figure is missing).
The Grängesberg mill treats the bre of own mine. The ore body now in working is a huge bed 1, 400 m long and 90 m (maximum width, av. 40 m) wide, dipping 70°. The ore minerals are magnetite and hematite, assaying 60% Fe and 1% P.
Handpicking, magnetic separation and tabling for concentrating magnetite and hematite and flotation for recovering apatite in gangue material are favourably applied.
Two plants “Södra verket” and “Hüller” are running separately, the former is the old plant having capacity of 190 t/hr, (20 hours per day), the latter was built recently and has capacity of 175 t/hr (10 hours per day). Apatite concentration is.practised in this plant.
Production of ores is as follows:-
Hoisted (tons) Ores (tons)
1936 2, 071, 543.0 1, 416, 544.
1937 2, 250, 000.0 1, 500, 000.0 (estimation)View full abstractDownload PDF (2081K) -
1940 Volume 56 Issue 657 Pages 33-46
Published: January 22, 1940
Released on J-STAGE: July 13, 2011
JOURNAL FREE ACCESSDownload PDF (3672K)
- |<
- <
- 1
- >
- >|