抄録
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.
