Showing papers on "Sulfide published in 1975"

Precipitation of Mississippi Valley-type ores

Abstract: Solubilities of galena in sodium chloride brines at temperatures near 100 degrees C are such that rather acid conditions are required to transport ore quantities of lead if the required reduced sulfur is transported in the same solution. If either calcite or dolomite is stable in the brine, this degree of acidity is ruled out, and if chalcopyrite is stable, the brine must be not only quite acid but highly reduced. Formation waters probably do not attain this degree of acidity, so to transport ore quantities of lead their reduced sulfur content must be very low, and must therefore be supplied at the site of deposition, causing precipitation. Mississippi Valley-type orebodies represent sites where metals from basinal brines and sulfide from limestones got together for considerable lengths of time, and the migration of H 2 S through the limestone to the site is at least as important as the flow of metal-bearing brine through the basin.

Colorless sulfur bacteria and their role in sulfur cycle

Abstract: The bacteria belonging to the families of the Thiobacteriaceae, Beggiatoaceae and Achromatiaceae are commonly called the colourless sulfur bacteria. While their ability to oxidize reduced inorganic sulfur compounds has clearly been established, it is still not known whether all these organisms can derive metabolically useful energy from these oxidations. During the last decades research has mainly focussed on the genus Thiobacillus. Bacteria belonging to this genus can oxidize a variety of reduced inorganic sulfur compounds and detailed information is available on the biochemistry and physiology of these energy-yielding reactions. The thiobacilli, most of which can synthesize all cell material from CO2, possess a well-regulated metabolic machinery with high biosynthetic capacities, which is essentially similar to that of other procaryotic organisms. Although the qualitative role of colourless sulfur bacteria in the sulfur cycle is well documented, quantitative data are virtually absent. Activities of colourless sulfur bacteria in nature must be related to direct and indirect parameters, such as: the rate of oxidation of (S35) sulfur compounds, the rate of C14O2-fixation, the rate of acid production and numbers and growth rates of the bacteria. However, chemical reactions and similar activities of heterotrophic organisms mask the activities of the colourless sulfur bacteria to various extents, depending on the condition of the natural environment. This interference is minimal in regions where high temperature and/or low pH allow the development of a dominant population of colourless sulfur bacteria, such as hot acid sulfur springs, sulfide ores, sulfur deposits and some acid soils. The oxidation of inorganic sulfur compounds is carried out by a spectrum of sulfur-oxidizing organisms which includes: 1) obligately chemolithotrophic organisms 2) mixotrophs 3) chemolithotrophic heterotrophs 4) heterotrophs which do not gain energy from the oxidation of sulfur compounds but benefit in other ways from this reaction, and 5) heterotrophs which do not benefit from the oxidation of sulfur compounds. The spectrum is completed by a hypothetical group of heterotrophic organisms, which may have a symbiotic relationship with thiobacilli and related bacteria. Such heterotrophs may stimulate the growth of colourless sulfur bacteria and thereby contribute to the oxidation of sulfur compounds. Future research should focus in the first place on obtaining and studying pure cultures of many of the colourless sulfur bacteria. In the second place, studies on the physiological and ecological aspects of mixed cultures of colourless sulfur bacteria and heterotrophs may add to a better understanding of the role of the colourless sulfur bacteria in the sulfur cycle.

Photosynthetic sulfide oxidation by Chloroflexus aurantiacus, a filamentous, photosynthetic, gliding bacterium.

Abstract: Chloroflexus, a newly described genus of filamentous, photosynthetic, gliding bacteria, oxidizes sulfide anaerobically under photoautotrophic or photoheterotrophic growh conditions and deposits elemental sulfur outside the cell. The formation of sulfur granules outside the cell supports the idea that this organism is related to the green sulfur bacteria (Chlorobiaceae).

Production of p-phenylene sulfide polymers

Abstract: A method is provided for producing a p-phenylene sulfide polymer by contacting at least one p-dihalobenzene, at least one alkali metal sulfide, at least one alkali metal carboxylate, at least one organic amide and at least one alkali metal hydroxide to form a composition at polymerization conditions. The use of an alkali metal hydroxide in addition to the other compounds used in the reaction mixture results in p-phenylene sulfide polymers of higher molecular weight than produced without the alkali metal hydroxide, as evidenced by lower melt flow of the polymer than produced by the compared methods.

Synergistic combinations of hydrated potassium borate, antiwear agents, and organic sulfide antioxidants

Abstract: A synergistic extreme-pressure lubricating composition comprising an oil of lubricating viscosity having dispersed therein: (1) 1-60 weight percent of hydrated potassium borate microparticles having a boron to potassium ratio of about 2.5 to 4.5 (2) from 0.01 to 5.0 weight percent of an antiwear agent selected from (a) a zinc dihydrocarbyl dithiophosphate having from 4 to 20 carbons in each hydrocarbyl group; (b) a C 1 -C 20 amine salt of a dihydrocarbyl dithiophosphoric acid having from 4 to 20 carbons in each hydrocarbyl group; (c) a zinc alkyl aryl sulfonate; or (d) mixtures thereof, and (3) from 0.1 to 5 weight percent of an oil-soluble antioxidant organic sulfur compound containing from 3 to 40 weight percent sulfur, which sulfur is present as organic sulfide or polysulfide or mixtures thereof.

C–S Stretching Vibrations and Molecular Conformations of Isobutyl Methyl Sulfide and Related Alkyl Sulfides

Abstract: The Raman and infrared spectra of isobutyl methyl sulfide and related alkyl sulfides were measured. The Raman spectra of the liquid, unannealed solid, and annealed solid of isobutyl methyl sulfide were compared and skeletal normal vibrations of possible rotational isomers were treated. Three rotational isomers were found to coexist in the liquid state whereas only one isomer was observed in the annealed solid. The energy differences among the three rotational isomers were measured. The correlations between the CH2–S stretching frequencies and molecular conformations were established, in common, for the molecules of isobutyl methyl sulfide, methyl propyl sulfide and ethyl methyl sulfide.

Polyarylene sulfide resin alloys

Abstract: Thermoplastic resin alloys containing polyphenylene sulfide resin and at least one other thermoplastic resin selected from the group consisting of polyarylsulfones, polyphenylene oxides, and polyarylcarbonates are disclosed which have certain physical properties that are better than those of at least one of the resins employed in preparing the alloy. Also, specific polyphenylene sulfide/polyarylsulfone alloy compositions are disclosed which have certain physical properties that are better than those of either the polyphenylene sulfide or the polyarylsulfone employed.

Production of arylene sulfide polymers

Abstract: A method by which arylene sulfide polymers are produced by admixing p-dihalobenzene, optionally together with a polyhalo aromatic compound having more than two halogen substituents per molecule, an alkali metal sulfide, an alkali metal carboxylate or a lithium halide, an alkali metal hydroxide, and N-methyl-2-pyrrolidone at polymerization conditions with the addition of carbon dioxide either during the polymerization or upon completion of the polymerization but prior to removal of N-methyl-2-pyrrolidone by distillation at elevated temperatures thereby producing a polymer, after washing, of lower melt flow than is obtained without the addition of carbon dioxide. In an embodiment of the invention the use of carbon dioxide makes unnecessary the use of vacuum distillation in recovering N-methyl-2-pyrrolidone from the reaction effluent and also makes possible improved recovery of N-methyl-2-pyrrolidone.

Catalytic incineration of hydrogen sulfide from gas streams

Abstract: A process for the conversion of H 2 S to SO 2 in a feed gas containing H 2 S is effected by oxidation with air or oxygen at temperatures between 300° and 900° F. The oxidation is conducted in the presence of an extremely stable oxidation catalyst comprising an oxide and/or sulfide of vanadium supported on a non-alkaline porous refractory oxide. The preferred catalyst comprises between 5 and 15 wt. % V 2 O 5 on hydrogen mordenite or alumina. Hydrogen, carbon monoxide, light hydrocarbons, and ammonia present in the feed gas are not oxidized. The invention is especially contemplated for use in treating waste gases from geothermal steam power plants.

Charge-transfer intermediate in the reaction of thioketone with nucleophiles.

Abstract: Thiobenzophenone reacts with butyllithium, phenyllithium, and sodium ethoxide in ethanol giving benzhydryl butyl sulfide, benzhydryl phenyl sulfide, and dibenzhydryl disulfide, respectively. On the other hand di-t-butyl thioketone affords 2,2,4,4-tetramethylpentane-3-thiol, 2,2,4,4-tetramethyl-3-phenylpentane-3-thiol, and 2,2,4,4-tetramethylpentane-3-thiol by the reaction with butyllithium, phenyllithium, and sodium ethoxide in ethanol, respectively. Product analyses and tracer experiments with deuteriums have revealed that these reactions proceed through a charge-transfer mechanism.

Catalytic process for ozonation of water containing organic contaminants

Abstract: An improved catalytic process for the ozonation of water containing organic contaminants is disclosed. In this process the water, which may be either waste water or potable water, containing organic contaminants is contacted with ozone, preferably at a pH in the range of about 6.8 to about 7.8 (controlled by buffering if necessary), in the presence of a mixed heterogeneous catalyst comprising water insoluble salts, preferably an insoluble carbonate, sulfate, oxide, halide or sulfide, of at least two metals selected from the group consisting of copper, cadmium and the group VIII metals, preferably iron, cobalt or nickel although other group VIII metals such as platinum or Palladium may be used if desired. In a preferred embodiment, the catalyst is supported on an insoluble carrier such as aluminum oxide or a simple or complex silicate and is of a controlled particle size and density, preferably generally spherical shaped particles having an average diameter of from 1/2 to 5 millimeters, so as to have a settling rate of from 15 to 150 feet per hour in water at 20° C. Low cost catalysts, made from (a) incinerator ash containing substantial amounts of iron and copper and/or nickel or (b) waste pickling liquor (enriched if necessary with copper and/or nickel compounds), are described.

Production of branched arylene sulfide polymers

Abstract: A method is provided for producing branched arylene sulfide polymers by contacting at least one p-dihalobenzene, at least one polyhalo aromatic compound having more than two halogen substituents per molecule, at least one alkali metal sulfide, at least one lithium carboxylate or lithium chloride, N-methyl-2-pyrrolidone, and at least one alkali metal hydroxide. The use of the polyhalo aromatic compound, which is employed in minor amounts, results in a polymer of reduced melt flow, which, without prior curing, can be molded, extruded, or spun into fibers.

Corrosion of Condenser Tube Alloys in Sulfide Contaminated Brine

Abstract: Increasing sulfide pollution of harbors and river estuaries has markedly increased corrosion of surface condenser alloys using once through cooling water. A laboratory study was conducted of several condenser tube alloys in flowing buffered sodium chloride solution, contaminated periodically with sulfide. The results showed that alternate treatment with sulfide and air was much more aggressive than air alone or sulfide alone. Corrosion performance of the alloys is compared.

Electrochemistry of Sulfide Minerals

Abstract: In recent years there has been an increasing interest in the electrochemical properties of metal sulfides. Our main sources of copper, lead, zinc, and nickel occur as sulfides and they are converted to the metal by pyrometallurgical processes which produce gaseous sulfur dioxide. The environmental requirements being imposed on sulfide smelters have led to a greater effort to develop hydrometallurgical routes for the treatment of sulfides in order to avoid the evolution of sulfur dioxide. These processes involve the oxidation of sulfides to sulfur or sulfate either using oxidants such as oxygen, ferric ion, or cupric ion1 or by direct anodic oxidation in an electrolyte.2 The oxidation of sulfides by an oxidant can be regarded as an electrochemical reaction with the cathodic reduction of the oxidant and the anodic oxidation of the sulfide,3 and it can consequently be studied by electrochemical techniques. Recent work4,5 has also shown that flotation, a key process in concentrating sulfide ores, can be electrochemical in nature.

Process for removing sulfur oxides and/or nitrogen oxides from waste gas

Abstract: Sulfur oxides and/or nitrogen oxides are removed from waste gas containing the same by adding chlorine dioxide or ozone gas to the waste gas in case where nitrogen monoxide is contained in the waste gas, and by scrubbing the waste gas with an aqueous scrubbing solution containing the sulfite of alkali metals or ammonium and oxidation retardant consisting of the sulfide, polysulfide or thiosulfate, of alkali metals or ammonium and thiourea.

Heavy Metal Humates And Their Behavior Against Hydrogen Sulfide

Abstract: Modern research on macromolecular humus has revealed the binding capacity of this type of humus towards heavy metal ions. While humic substances are active in the freeing and uptake of such metal ions from disintegrating rocks, deposition of these ions will result from the contact between the metal-humate complexes and microbially generated hydrogen sulfide. Such a process of deposition of metal sulfides in marine sediments could have been the main factor in the creation of certain geological so-called stratiform sulfide ore formations of considerable economic importance. In order to study the mechanisms involved in more detail, artificial metal-humates were made. Two types of natural humus (“aqua humus” and “sulfite humus”) were selected for their sorption capacity. Metal-humate complexes were made by adding pure metal powders in different quantities to various humus suspensions, while air was expelled by bubbling nitrogen gas through the flasks. After thorough contact the suspensions were filtered and measured for their metal concentrations with the aid of X-ray fluorescence. Metal sulfides were created by percolating hydrogen sulfide gas through the metal-humate suspensions under controlled circumstances. Precipitated metal sulfides were collected in media such as filter paper, glass beads, silica gel, quartz sand, porous glass, or clay. X-ray identification to the sulfides formed was employed. Unprecipitated metal humates were measured from the remaining suspensions with X-ray fluorescence analysis. Apart from conclusions in regard to the sorption mechanisms involved, conclusions on environmental factors required for this type of mineral deposition, as well as conclusions on morphological aspects of microscopic sulfide spherules (“framboidal textures”) found in recent and fossil marine sediments, are drawn from the laboratory observations described.

The scaling of iron in oxygen and sulfur-containing gases

Abstract: The following possible conditions for the simultaneous formation of oxide and sulfide on iron in oxygen and sulfur-containing gases are considered: (7) simultaneous thermodynamic stability of oxide and sulfide; (2) temporal changes in gas composition; (3) intermediary cracking of the oxide film; (4) solubility and diffusion of sulfur in the oxide (lattice diffusion); (5) kinetic conditions for simultaneous oxide and sulfide formation at the scale-gas interface.

Production of aromatic sulfide/sulfone polymers

Abstract: High molecular weight aromatic sulfide/sulfone polymers are produced by reacting a dihalo aromatic sulfone, an alkali metal sulfide other than lithium sulfide, an organic amide, and an alkali metal carboxylate. Use of the alkali metal carboxylate results in polymers of high molecular weight and satisfactory melt flow properties having utility as coatings, films, molded objects, fibers, and the like.