Showing papers on "Sulfide published in 1969"

Microbial Dissimilatory Sulfur Cycle in Acid Mine Water

Abstract: Ferric, sulfate, and hydrogen ions are produced from pyritic minerals associated with coal as a result of autotrophic bacterial metabolism. Water carrying these ions accumulated behind a porous dam composed of wood dust originating at a log-cutting mill. As water seeped through the porous dam, it was enriched in organic nutrients which then supported growth and metabolism of heterotrophic bacteria in the water downstream from the dam. The heterotrophic microflora within and below the sawdust dam included dissimilatory sulfate-reducing anaerobic bacteria which reduce sulfate to sulfide. The sulfide produced caused the chemical reduction of ferric to ferrous ion, and black FeS precipitate was deposited on the pond bottom. A net increase in the pH of the lower pond water was observed when compared to the upper pond water. Microbial activity in the wood dust was demonstrated, and a sequence of cellulose degradation processes was inferred on the basis of sugar accumulation in mixed cultures in the laboratory, ultimately yielding fermentation products which serve as nutrients for sulfate-reducing bacteria. Some of the microorganisms were isolated and characterized. The biochemical and growth characteristics of pure culture isolates were generally consistent with observed reactions in the acidic environment, with the exception of sulfate-reducing bacteria. Mixed cultures which contained sulfate-reducing bacteria reduced sulfate at pH 3.0 in the laboratory with sawdust as the only nutrient. Pure cultures of sulfate-reducing bacteria isolated from the mixed cultures did not reduce sulfate below pH 5.5.

Liquidus phase relations in the FeS-FeO-Fe 3 O 4 -SiO 2 system, and their application in geology

Abstract: Experimental studies, sulfides in silicate magmas, genesis of sulfide ores, oxidation model

Acid gas removal from gas mixtures

Abstract: An improved solvent and process for treating and separating acid gas, particularly hydrogen sulfide from gas mixtures containing the same, such as natural gas mixtures containing hydrogen sulfide, carbon dioxide and methane. The process involves the use of a solvent comprising a mixture of dimethyl ethers of polyethylene glycols to absorb the hydrogen sulfide and part of the carbon dioxide under superatmospheric pressure. The solvent containing dissolved hydrogen sulfide and carbon dioxide is flashed at reduced pressure to remove most of the carbon dioxide and produce a ''''semilean'''' solvent. Part of the semilean solvent is recycled to an intermediate part of the absorber; the remaining semilean solvent containing hydrogen sulfide is subjected to an oxygen containing gas under conditions that result in complete removal of the hydrogen sulfide to produce a ''''lean'''' solvent. The lean solvent is recycled to the top of the absorber. By the use of two solvent feeds to the absorber, the economy of the process is improved.

Thermal degradation of polymers with phenylene units in the chain. II. Sulfur‐containing polyarylenes

Abstract: Poly(p-phenylene sulfide), a poly(arylene sulfone), and a poly(arylene sulfonate) were subjected to thermal degradation in vacuo, at temperatures between 250 and 620°C. The volatile and solid degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. The major decomposition product of poly-(phenylene sulfide) is a condensate, which consists of di- and trimeric chain fragments, dibenzothiophene, and possibly thianthrene. The residual polymer loses two thirds of its sulfur as hydrogen sulfide, however, one third is retained even at 620°C. The most characteristic decomposition reaction of the polysulfone and of the polysulfonate is the almost complete removal of the sulfur as sulfur dioxide. The elimination of sulfur dioxide is practically complete at 450°C for the polysulfone and at 350°C for the polysulfonate.

Fluorescence determination of sub-parts-per-billion hydrogen sulfide in the atmosphere

Abstract: In the following work, a fluorescnece method for the determination of sulfur as sulfide in organic compounds has been applied to the measurement of atmospheric hydrogen sulfide. This method shows high sensitivity and reliability, and is suitable for the measurement of hydrogen sulfide background levels.

Assimilatory and Dissimilatory Metabolism of Inorganic Sulphur Compounds by Micro-Organisms

Abstract: Publisher Summary Sulfur is an essential element for the growth and activity of all living cells. Sulfur metabolism involves both reductive and oxidative processes and the co-operative action of these processes gives rise to the sulfur cycle in which sulfur is continually recycled between sulfate and reduced forms such as sulfide and sulfur-amino acids. The cycle embraces an eight-electron change between sulfate and sulfide and can involve the formation of intermediates, which have no stable counterparts in chemistry. The two classes of biological sulfate reduction includes—namely,(1) assimilatory, small-scale reductions of sulfate to sulfur-containing amino acids and (2) dissimilatory, large-scale transformations of sulfate to sulfide, which are linked to energy-yielding reactions in the organism. This chapter describes assimilatory and dissimilatory terms to distinguish transformations of inorganic sulfur compounds, which lead to the formation of cell constituents from those oxidative and reductive processes that are concerned primarily with energy metabolism. Essentially, assimilatory sulfate-reducing microorganisms depend on 3′-Phosphoadenylylsulfate (PAPS) reductase for cysteine biosynthesis and dissimilatory sulfur metabolism—both reductive and oxidative— are linked to Adenylylsulfate (APS) reductase.

Melting curves of sphalerite, galena, and pyrrhotite and the decomposition curve of pyrite between 30 and 65 kilobars

Abstract: The melting slopes of galena and pyrrhotite were determined to be +5 and +6°C/kb, whereas the slope of the decomposition curve of pyrite was found to be +9°C/kb. Zinc sulfide has a negative melting slope of −5°C/kb up to 40 kb, where the slope changes to a positive one of about +3°C/kb. The melting slopes of the metal sulfides indicate that, if silicate magma forms at depths below 80 kb, sulfide magma should also form. Its downward intrusion could help to explain the origin of deep focus earthquakes.

Two-phase hydrocarbon conversion system

Abstract: HYDROCARBONS ARE HYDROCRACKED,HYDROFINED, HYDROGENATED AND/OR DEMETALLIZERD BY INTIMATE CONTACTING AT ELEVATED TEMPERATURES IN THE PRESENCE OF HYDROGEN WITH AN AQUEOUS DISPERSION OF A SULFIDE OF MOLYBDENUM, VANADIUM AND/OR RHENIUM. THE CATALYTICALLY ACTIVE COMPONENTS ARE CONVENIENTLY PRODUCED IN THE AQUEOUS PHASE BY REDUCTION AND/OR SULFURIZATION OF THE CORRESPONDING WATER SOLUBLE SULFIDES, OXIDES, ACIDS OR SALTS. THESE METHODS ARE PARTICULARLY ATTRACTIVE FOR THE SELECTIVE DEMETALLZATION AND MOLECULAR WEIGHT REDUCTION AND/OR REMOVAL OF ASPHALTENES AND RESINS.

Massive sulfide deposits and volcanism

Abstract: 9Massive sulfide deposits, consisting of pyrite and/or pyrrhotite and various ratios of chalcopyrite, sphalerite, and galena, are commonly associated with volcanic rocks that accumulated in eugeosynclines.9 They are related genetically to these volcanic rocks rather than to granitic rocks. The source of the base metals may have been primary volcanogenic concentrations, dispersed metals in volcanics, or later magmas. Hydrothermal (meaning simply 9hot-water9) solutions of various temperatures, probably containing alkali chlorides, have commonly been the transporting agent. The trace-element content of sulfides (Se and V in pyrite) and isotope studies are promising directions for research on genesis.

Annealing of arylene sulfide polymers

Abstract: THE PHYSICAL PROPERTIES OF SHAPED BODIES OF ARYLENE SULFIDE POLYMERS ARE IMPROVED BY ANNEALING AT A TEMPERATURE BELOW THE MELTING POINT OF THE POLYMER.

Oxidation of Pyrite

Abstract: The decomposition of pyrite was investigated in a thermo-balance. In neutral or reducing gases it decomposes between 550° and 700°C to volatile sulfur and ferrous sulfide. In oxygen it oxidizes in two stages: between 445° and 520°C, it forms sulfur dioxide and ferrous sulfide: between 610° and 660°C. it forms more sulfur dioxide and hematite’In air Or with fast cycles, the reactions are overrun and do not show the two stages. Carbon dioxide reacts very slowly and gives magnetite. Water vapor had an insignificant effect on the reactions. DTA did not show the second stage with normal technique. Fine grinding and testing in oxygen disclosed the reaction.

Sulfur isotope fractionation in coexisting sulfides from the Heath Steele B-1 orebody, New Brunswick, Canada

Abstract: Isotopic fractionations between given sulfide minerals are relatively constant throughout the B-1 orebody and between all six deposits [studied]. The mean pyrite-sphalerite, sphalerite-galena, and pyrite-galena fractionations [differences] are approximately 1, 2, and 3 permil, respectively. These consistencies together with the similarity of the silicate mineralogies in the sulfide deposits, their wall rocks, and the country rocks indicate that sulfur isotopic equilibrium was closely approached at a fairly uniform temperature. It is suggested that low-rank regional metamorphism has generated the observed fractionations and caused local isotopic homogenization with respect to given minerals.

The Microwave Spectrum, Structure, and Dipole Moment of Ethylene Episulfoxide

Abstract: The microwave spectra of the normal species as well as the 13C and 34S isotopic molecules of ethylene episulfoxide have been observed. The rotational constants thus obtained lead to the following structural parameters: S–O=1.483±0.003 A, C–S=1.822±0.003 A, ∠OSC=111°1′±10′, ∠CSC=48°46′±10′, on the assumption that the C–H distance and the ∠HCH and ∠H2CC angles are the same as those of ethylene sulfide. From the Stark shifts, the dipole moment has been determined to be μa=3.61±0.04 D, μc=0.89±0.01 D and μtotal=3.72±0.04 D. The bond nature of S–O and C–S has then been discussed on the basis of these data.

Reactions of Diarylphosphines, Their Oxides and Sulfides with Isothiocyanates and Thiocyanic Acid

Abstract: N-Substituted thiocarbamoyldiarylphosphine oxides and sulfides were prepared by the addition reaction of diarylphosphine oxides and diphenylphosphine sulfide with isothiocyanates. Diarylphosphine oxides and diphenylphosphine reacted with ammonium thiocyanate under hydrogen chloride stream to produce diarylphosphinyl- and diarylthiophosphinyl-substituted bis(iminomethyl) sulfides, which are a new type of sulfide. Diphenylphosphine also reacted with thiocyanic acid in ether to give thiocarbamoyldiphenylphosphine and bis(diphenylphosphinyliminomethyl) sulfide. Mechanisms for formation of these bis(iminomethyl) sulfides have been discussed.

Flotation of sulfide ores

Abstract: An improvement in the concentration of ores by flotation which comprises subjecting a sulfide ore in the form of a pulp to a flotation process in the presence of an effective quantity of a flotation collector corresponding to the formula WHEREIN A is a radical corresponding to the formula D R A W I N G

Copper-poly (arylene sulfide) laminates and process for preparing same

Abstract: Laminate structures of a poly(arylene sulfide) coating composition on a copper substrate are formed by pretreating the copper substrate with a basic nitrogenous compound or salt thereof prior to the coating of the substrate with the poly(arylene sulfide) coating composition.