Sulfide systems

H.S.S. High sulfidation system L.S.S. Low sulfidation system Q.P. Quartz porphyry... 

Barton, P.B. Jr. and Toulmin, P. Ill (1964) The electrum-tarnish method for the determination of the fugacity of sulfur in laboratory sulfide systems. Geochim. Cosmochim. Acta, 238, 619-640. 

Systems that are exposed to excessive turbulence of anaerobic wastewater and a potential increased release of hydrogen sulfide. Systems with a risk for increased turbulence are inlet structures, drops, cascades, sharp bends and inverted siphons. As an example, changes in the flow regime from a pressure pipe into a gravity sewer may give rise to the release of hydrogen sulfide. Corrosion of the sewer pipe wall is often pronounced near the daily water... 

Chemical addition for the removal of inorganic compounds is a well-established technology. There are three common types of chemical addition systems that depend upon the low solubility of inorganics at a specific pH. These include the carbonate system, the hydroxide system, and the sulfide system. 

In reviewing the basic solubility products for these systems, the sulfide system removes the most inorganics, with the exception of arsenic, because of the low solubility of sulfide compounds. This increased removal capability is offset by the difficulty in handling the chemicals and the fact that sulfide sludges are susceptible to oxidation to sulfate when exposed to air, resulting in resolubilization of the metals. The carbonate system is a method that relies on the use of soda ash (sodium carbonate) and pH adjustment between 8.2 and 8.5. The carbonate system, although... 

Figure 5. Comparison of predicted and experimental bubble point pressures for methanol-hydrogen sulfide system ((O, A, VJ (24) (-------) predicted)...

Several computer-based techniques have been developed for more specific applications. Truesdell (45) describes a computer program for calculating equilibrium distributions in natural water systems, given concentrations and pH. Edwards, et al. (31, Z2) have developed computer programs for treating volatile weak electrolytes such as ammonia, carbon dioxide and hydrogen sulfide systems however, in their present state these programs (presumably) do not accommodate metallic species in solutions. 

Barrett, T.J. MacLean, W.H. 1999. Volcanic Sequences, Lithogeochemistry, and Hydrothermal Alteration in Some Bimodal Volcanic-Associated Massive Sulfide Systems. Reviews in Economic Geology, 8, 101-131. 

In cupric sulfide systems, a high stability constant of a chelate does not necessarily mean a slow release of metal ions, due to the extremely high rates in both association and dissociation of the chelate. For instance, the reactions of chelates, Cu(TMD)22+ and Cu(DETA)22+, with TAA under standard conditions A finish within 2 min at 25°C to yield rather small CuS particles of 40 to 50 nm, despite the respective high stability constants, 10169 and 102l comparable to or even much higher than the stability constants of EDTA chelates of the other kinds of metal ions, such as Cd2+, Zn2+, and Pb2+, which are much slower in releasing these metal... 

Fenchel TM, Riedl RJ (1970) The sulfide system A new biotic community underneath the oxidized layer of marine sand bottoms. Marine Biol 7 255-268 Fike DA, Grotzinger JP, Pratt LM, Summons RE (2006) Oxidation of the Ediacaran ocean. Nature 444 744-747... 

Metal sulfides belong to the most important classes of compounds because they are of general significance for geochemistry (they are the most important ores for many metals), analytical and structural chemistry, and biochemistry (metal sulfide systems act as electron transfer systems) as well as catalysis (a high percentage of industrially used heterogeneous catalysts are sulfides) and materials science. 

Recently a fairly inexpensive way of high-temperature experimentation has been found to investigate refractory sulfides and related multicomponent systems up to temperatures of nearly 2000 °C using resistance furnaces. These techniques are discussed below and applied to some sulfide systems, in particular of those metals which belong to the VI-B group. The binary systems chromium-sulfur, molybdenum-sulfur, tungsten-sulfur, as well as some other ternary and quaternary systems and their reactions are reviewed and completed within the limits of the new experimental procedure. 

With regard to the above-mentioned classification of sulfide systems, a region of two immiscible liquids should be assumed at high temperatures, above the critical temperature of sulfur. These liquidus reactions are part of present investigations, the results of which will be published at a later date. 

The previously studied ternary sulfide systems included chromium, molybdenum, and/or tungsten with the added elements iron, copper etc. While other isotherms may be available, only that of 700 °C will be depicted. Higher temperature equilibria are deduced from these and their reactions are presented. Lower temperature phase equilibria of geologic importance are referenced. 

Some of the following ternary sulfide systems are briefly discussed with respect to related mineral occurrences. In addition to the 700 °C isotherms and the temperature-... 

The aim of the present experimental work is the study of reactions and stability relations within multicomponent sulfide systems of geologic interest. Such are ... 

The outline of binary, ternary, and quaternary sulfide systems with the VI-B group elements (e. g., Cr, Mo, W) is not claimed to be complete. However, it does represent the current status of research. 

The binary sulfide systems discussed in this study are mostly complete . Apart from the upper P—T stability of the 7-phase, the Cr—S system is completely described. 

The 1.5 V lithium iron sulfide system competes directly with the alkaline manganese system for high-performance electronic applications. It gives better high-rate performance than the alkaline manganese system. The other main commercial systems are the 3 V lithium carbon monofluoride (Li-CFx) system, and the lithium manganese dioxide (Li-Mn02) system. 

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