Sulphur gases

Dissolved gases (oxygen, nitrogen, carbon dioxide, ammonia, sulphurous gases). 

STEUDLER, P.A., andKIJOWSKI, W. (1984). Determination of reduced sulphur gases in air by solid adsorbent preconcentration and gas chromatography. Anal.Chem. 56 1432-1436. 

Liquid Sulphur Dioxide.—Sulphur dioxide was the first gas to be converted to the liquid state.4 It can be liquefied by passage through a tube cooled to below —10° C. in a freezing mixture,5 but commercially the liquid is produced by compression.6 The sulphurous gases from burning iron pyrites or some other suitable source, containing some... 

Sulphur dioxide and sulphurous gases attack basic rocks and glasses superficially at high temperatures (900° C.) with the formation of water-soluble sulphates, chiefly sodium sulphate.3 It is probable that such reaction and the solution of the products in hot springs during the early post-volcanic period explain the origin of alkaline sulphated thermal waters. 

Viking Energy is the first cargo/offshore support vessel to be fuelled with LNG. The celebrated project has attracted much attention for its efforts and innovative approach lead by the Norwegian shipping company Eidesvik AS3. The quoted emissions reduction of NOx and CO2 is 84% and 20% respectively as compared with conventional marine diesel operation. Furthermore, the sulphurous gases are practically zero [20],... 

Inomata Y. Iwasaka Y. Osada K. Hayashi M. Mori I. Kido M. Hara K. and Sakai T. (2006). Vertical distributions of particles and sulphur gases (volatile sulfur compounds and S02) over East Asia Comparison with two aircraft-borne measurements under the Asian continental outflow in spring and winter. Atmospheric Environment, 40(3), 430-444. 

Many metalliferous mineral deposits formed at depth are in the reduced state. Where they interface with the near-surface oxidising environment, there is considerable chemical reactivity. This typically takes the form of sulphide oxidation, which includes the generation of several meta-stable sulphur gases that have been shown to be useful in mineral exploration (Chapter 8). Incompletely oxidised sulphide anions and compounds are transported away from mineral deposits at depth by the groundwater, and can be mapped at surface as dispersion patterns of HjS (Chapter 9). 

The odour of oxidising sulphides is a well-known geological phenomenon. This observation, combined with the existence of a wide range of volatile sulphur species, has led to a number of attempts to develop methods using sulphur gases as an aid to exploration. 

The potential application of sulphur-gas surveys was first discussed in the literature by Glebovskaya and Glebovskii (1960). Their attempts to detect sulphur gases were unsuccessful, despite the odour of sulphur. This failure was ascribed to the poor sensitivity of the (unspecified) analytical system. In the next few attempts to detect sulphur gases associated with mineralisation (Kravtsov and Fridman, 1965 Elinson et al., 1970), the detection systems used were either not described or appear to be of insufficient sensitivity. 

Subsequently, a period of particularly active research into the exploration value of sulphur gases yielded promising results. Hinkle (1978), Hinkle and Harms (1978) and Hinkle and Kantor (1978) used molecular sieves as passive adsorbents of sulphur gases. Lovell (1979), Lovell et al. (1980), Hale and Moon (1982), Hinkle and Dilbert (1984) and Oakes and Hale (1987) used the soils themselves. McCarthy et al. (1986) used soil gases and Hinkle (1986) used both soils and soil gases. The objective of this chapter is to present the rationale and the results of the investigations from this period. 

In contrast, their experiments showed that decomposing sulphides evolved only CS2 and COS, in order of decreasing abundance. In addition, measurements of the Eh and pH of the final solutions from moist and saturated sulphide mineral experiments showed that CSi and COS were formed under metastable oxidising conditions (Fig. 8-5). Pyrite produced the largest amounts of sulphur gases, more than chalcopyrite, sphalerite and galena (Fig. 8-6). Moist (not saturated) and non-sterile (as compared to sterile) conditions enhanced sulphur-gas evolution from pyrite samples. Sulphur gas evolution from saturated pyrite samples is shown in Fig. 8-7. 

Subsequent to the experiments of Taylor et al. (1982) on sulphur gases derived from decomposing sulphide minerals, Hinkle et al. (1990) performed simulated weathering experiments on ground drill cores from the Santa Cruz porphyry copper deposit, Casa Grande, Arizona. Fresh, finely-ground samples were placed in sealed tubes, either in contact with a small quantity (0.8 ml) of water or exposed to water vapour but not in... 

In summary, the sulphur gases most likely to be related to sulphide mineralisation in the natural environment are CS2, COS, H2S and (CHj)2S. Many chemical reactions can occur between the time a sulphur compound (volatile or non-volatile) leaves a deposit and the time a volatile sulphur compound appears near the ground surface above the deposit. Bacterial action probably plays a large role in the formation of sulphur gases as they react with minerals in the deposit, with bedrock, with groundwater and with soil en route to the surface. Therefore, while gaseous sulphur compounds over or peripheral to sulphide mineralisation may be related to the mineralisation, the compounds may or may not have originated directly from the mineralisation. 

Sulphur gas eoncentrations (ppb by volume) from the decomposition of 20 g of 40-80 sulphide minerals under saturated conditions pyrite (circles) chalcopyrite (triangles) (squares) concentrations of sulphur gases <100 ppbv have been omitted for the sake of (from Taylor ct al., 1982). 

Various commercially-packed columns and packing materials are available and have been used for the separation and analysis of mixtures of sulphur gases (Bremner and Banwart, 1974 De Souza et al., 1975 Supelco, 1977). The most commonly-used columnpacking materials for sulphur-gas analysis are Chromosil 310, acetone-washed Porapak-QS and three types of Carbopak B. Selection must be based on the analytical data desired. Each of these packings separates different components and has advantages and disadvantages. 

Column packings for gas chromatographic determination of sulphur gases... 

Column packing material Sulphur gases separated Disadvantages... 

Other collection and analytical methods for soil-gas measurement involve the use of a portable mass spectrometer and the use of trained dogs (Kahma et al., 1975). Analytical methods for sulphur gases are summarised in Table 8-111. 

Sulphur gases in permeation devices are the usual means for calibrating the response of a gas chromatographic detector. Liquefied gases are sealed in Teflon tubes, or in glass or stainless steel tubes with Teflon "windows" on the ends. Gases permeate through the Teflon at a constant rate until the enclosed supply is exhausted. The rate of permeation is... 

The case history section of this chapter is severely limited by the absence of well-documented reports of the use of sulphur gases in mineral exploration. The case histories that follow are demonstrations of the ways in which sulphur gases delineate known mineral... 

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