The Origin of the sulphur of the sublimated sulphur deposit was considered on the basis of the solfataric gas measurement which was carried out by the writer at several mines. His inference was drawn as follows: The greater part of the sulphur that existed in such a deposit might be probably produced by the reaction of H₂S and SO₂ as shown in the equation 2H₂S+SO₂=2H₂O+3S. It may be taken that H₂S gas is of magmatic origin, and SO₂ comes from Oxidation of H₂S.(1) Being oxidized by O₂ in air, FeS₂ minerals which existed near the earth, surface decompose into H₂SO₄ and FeSO₄ as shown in the following: 2FeS₂+70₂+2H₂0=2H₂SO₄+2FeSO₄ (2) The underground water which dissolved H₂SO₄ and FeSO₄ would go downwards and encounter with such a heat source as magma. After it was evaporated, the superheated steam would ascend toward the surface as solfataric gas.(3) SO₂ gas and free sulphur are produced by the reaction of H₂S from lava and H₂SO₄ or FeSO₄ as shown in the follwing:
H₂S+ H₂SO₄= 2H₂O+ SO₂+S
H₂S+ 3H₂SO₄= 4H₂0+ 4SO₂
2H₂S+ FeSO₄= FeS₂+ SO₂+ 2H₂O
According to J. W. Mellor, it is reported that H₂S and SO₂ react immediately in the existence of a trace of water. But Also he says that they react slowly without water even if the superheated steam is present. Therefore, H₂S and SO₂ are spouted together from the solfatara with a greater amount of the superheated steam and the free sulphur of a minor quantity.

抄録全体を表示

In this paper, the authors report considerations of the experimental result obtained on Pyramid-cut of drifting 1 m of level.
The dimensions of the drift was 2.30m×2.10m. The rock-character was sulphur ore whose original rock was consisted of brecciated tuff.
Experimental investigations were rendered on the efficiency from working and economical stand point. The result may be summarized as follows:
(1) In case of 1 m drifting, the depth of. center cut can be taken preferably 80×90cm.
(2) The optimum frustum of the center cut can be gained when the base area of the frustum is 1.31m2 ie. 27.1% of the heading area and the cross sectional summit area 0.31m2 ie. 6.4% and the volume of excavation is about 0.61m3.
(3) The optimum height of the central position of center cut is about 45% of the height of the heading.
(4) The consumption of explosives in ordinary field drifting surpass 7.5kg/m (of which the center cut requires 27%) that determined experimentally, expending 55% more redundantly.

抄録全体を表示

The Bunsen-Schilling densimeters are produced by way of experiment, and the theoretical considerations and experimental studies are carried out. It is proved that this apparatus may serve the practical use measuring the high concentration f drained methane in mine.
The chief remarkable merits of this are the low cost and the high accuracy.

抄録全体を表示

In view of the fact that a wet cyclone is essentially a classifier, performance tests were carried out using 60-mm rubber-lined wet-cyclone experimental unit at the Mineral Dressing Laboratory, University of Tokyo. To evaluate the results of classification the method of Tromp's distribution curve is applied in relation to the particle size.
The influences of the following factors upon the separating size and the sharpness of classification were investigated:
1) Feed inlet pressure.
2) Dimensions of overflow finder and underfiow nozzle.
3) Pulp density of feed slurry.
It was indicated that the feed inlet pressure was preferred to be rather low. Other factors affecting the classification characteristics of the wet cyclone were also discussed, along with the performance data on wet cyclone practices at several mines in Japan.

抄録全体を表示

This paper describes the following results.
1) Solubilities of sodium carbonate at 19° and 29° were researched as the function of the concentration of sodium tungstate. These values serves as the foundation of recovery of excess sodium carbonate in the leach liguor obtained by the autoclave-soda process.
2) The addition of sodium hydroxide brought very good effect on the extraction from rich ore.
3) The tungsten in the leach liquor is reduced partly with impurities in the ore, therefore the yield of calcium tungstate from the leach liquor is 70-80% at the vicinity of pH 7. For the complete recovery, it is necesary to oxidize tungsten to hexavalent with an adequate oxidizing agent like sodium hypochlorite.

抄録全体を表示

An investigation on the solubilities of constituents of matte in slag was carried out. In order to approach as much as possible the equilibrium state, metal (Fe or Cu), matte (Cu-Fe-S) and slag (FeO-SiO₂-CaO) were melted together in a silica crucible. Subsequently the contens of Cu and S in the resulting slags were determined. The following results were obtained, indicating, also the evidence of ascribing the determined Cu and S to their solution in the slags.(1) The microscopic examination reveals the absence of suspended matte globules.(2) The amounts of dissolved Cu and S, when coexisting with the matte of a definite composition, settle down at fixed values with the lapse of time.(3) With an increase in matte grade, the contents of Cu dissolved in the slags increase, Whereas the contents of S decrease intensely. Thus, it is presumable that FeS is far superior to Cu2S in solubility.(4) When the mattes containing less than 60 pct Cu, the amounts of dissolved Cu correspond to about 0.5 pct of the matte grade. When the matte grade exceeds 60 pct, the amount of Cu rises increasingly.(5) The amounts of dissolved Cu and S increase with increasing temperature.

抄録全体を表示