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Showing papers on "Sodium sulfide published in 1997"


Journal ArticleDOI
TL;DR: In this article, a systematic study of the promoting effect of various elements on crystallization and texture of tungsten sulfide (WS2) thin films is presented, showing that the best crystallization at relatively low annealing temperatures Ta=650-750°C is achieved by adding sodium sulfide or nickel to the film, while the strongest texture is achieved with cobalt.
Abstract: A systematic study of the promoting effect of various elements on crystallization and texture of tungsten sulfide (WS2) thin films is presented. Best crystallization at relatively low annealing temperatures Ta=650–750 °C is achieved by adding sodium sulfide or nickel to the film, while the strongest texture is achieved with cobalt. An improvement of crystallization and texture is equally achieved with iron, manganese, or cesium. The promoting effect is mostly independent of the way the promoter is added. The promoting element can be added as a thin layer on the substrate or on the top of the WS2 film or it can be codeposited with the WS2 film. Since rheotaxy models cannot satisfactorily explain these results, the possibility of a catalytic growth mechanism is discussed.

34 citations


Journal ArticleDOI
TL;DR: In this article, the anomalous responses of Mw to conversion and to comonomer stoichiometry, observed in poly(p-phenylene sulfide) synthesis from p-dichlorobenzene and sodium sulfide are shown to be a consequence of unequal rate constants for the growth steps.
Abstract: The anomalous responses of Mw to conversion and to comonomer stoichiometry, i.e., deviations from expected classic A−A + B−B step-growth polycondensation behavior, observed in poly(p-phenylene sulfide) synthesis from p-dichlorobenzene and sodium sulfide are shown to be a consequence of unequal rate constants for the growth steps. The polymerization is simulated by a computer model based on the step-growth polymerization concept and includes cyclization and side reactions. Rate constants and activation energies for the growth and side reactions were obtained by measurements of reaction rates of actual reaction intermediates or model compounds, while those for cyclizations were estimated.

26 citations


Journal ArticleDOI
TL;DR: In this article, the authors showed that the catalytic efficiency of layered NiPS 3 intercalates is correlated with their ability to be reduced in depth when brought in contact with aqueous sodium sulfide.

24 citations


Journal ArticleDOI
TL;DR: In this paper, the potential of fly ash procured form coal-fired thermal power plants was studied as a heterogeneous catalyst in the oxidation of aqueous sodium sulfide solutions with hydrogen peroxide in the temperature range of 303-323 K.
Abstract: The potential of fly ash procured form coal-fired thermal power plants was studied as a heterogeneous catalyst in the oxidation of aqueous sodium sulfide solutions with hydrogen peroxide in the temperature range of 303–323 K. The effects of various parameters (source of fly ash, fly ash loading, initial concentrations of sodium sulfide and hydrogen peroxide, electrolyte and deactivation of catalytic effect of fly ash) were studied. For an initial sodium sulfide and hydrogen peroxide concentration of 26·98×10−2 kmol m−3 and 24·28×10−2 kmol m−3 respectively, only 4% (w/v) fly ash loading intensified the rate of oxidation by a factor of 4·52 over that without fly ash at 303 K. The deactivation of the catalytic effect of fly ash was found to be less than 20% even after six repeated uses. The kinetics of aqueous phase decomposition of hydrogen peroxide was also studied in the presence of fly ash in alkaline medium. ©1997 SCI

16 citations


Journal ArticleDOI
TL;DR: Amorphous spherical particles of nickel sulfide of 10 nm in diameter were synthesized by the controlled double-jet precipitation (CDJP) technique using nickel sulfate and sodium sulfide as discussed by the authors.
Abstract: Amorphous spherical particles of nickel sulfide of 10 nm in diameter were synthesized by the controlled double-jet precipitation (CDJP) technique using nickel sulfate and sodium sulfide. Cubic crystalline particles of 200 nm were obtained by aging dispersions of amorphous particles at 80 °C for more than a week, as long as the pH was kept between 3 and 3.5. Electrokinetic mobilities of these particles are reported, as well as color properties of their dispersions in liquids and in poly(vinyl alcohol) films are described.

14 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the kinetics of glassy and crystalline As2S3 in aqueous sodium sulfide and hydroxide solutions and suggested a mechanism of dissolving.
Abstract: Dissolution kinetics of glassy and crystalline As2S3 in aqueous sodium sulfide and hydroxide solutions was investigated. Glass, produced by rapid quenching contains frozen products of arsenic trisulfide dissociation — As4S4 and S. A strong change in the chemical behavior of g- and c-As2S3 has been found in its interaction with hydroxide ions. A mechanism of dissolving has been suggested.

13 citations


Journal ArticleDOI
TL;DR: The capability of Phascolosoma arcuatum to detoxify sulfide in anaerobic conditions was examined in this article, which indicated that rhodanese might act as a catalyst in the transfer of sulfur atoms from thiosulfate to HS−.
Abstract: The capability of Phascolosoma arcuatum to detoxify sulfide in anaerobic conditions was examined. Sulfane sulfur, which underwent cold cyanolysis, was the major excretory end product of sulfide detoxification during anoxia. Thiosulfate was not excreted into the external medium. Instead, it was absorbed by P. arcuatum and its absorption was stimulated by the presence of sodium sulfide (Na2S) in the incubation medium. The effective formation and excretion of sulfane sulfur by P.␣arcuatum required the presence of both Na2S and sodium thiosulfate (Na2S2O3). Results obtained indicate that rhodanese might be involved in sulfide detoxification in this sipunculid. Rhodanese could act as a catalyst in the transfer of sulfur atoms from thiosulfate to HS−. The body wall and the introvert were the main sites of sulfide detoxification. However, it is unlikely that epibiotic bacteria associated with the outside surface of the worm were involved in the detoxification process. A time-course study on the contents of thiosulfate and sulfane sulfur in the body wall of P. arcuatum incubated anaerobically in the presence of Na2S + Na2S2O3 verified that thiosulfate absorbed was utilized to detoxify sulfide to sulfane sulfur.

12 citations


Patent
06 Aug 1997
TL;DR: In this article, a coprecipitation-aided liquid-phase reaction process with an organic acid (preferably acrylic or methacrylic acid) incorporated in the reaction system was proposed to obtain a luminophor having a nano-structured structure and excitable in a low voltage range by forming a semiconductor of the group II to VI doped with an activator.
Abstract: PROBLEM TO BE SOLVED: To provide a method for producing a luminophor having a nano- structure and excitable in a low voltage range by forming a semiconductor of the group II to VI doped with an activator by a coprecipitation-aided liquid- phase reaction process with an organic acid incorporated in the reaction system. SOLUTION: This luminophor is obtained by a coprecipitation-aided liquid- phase reaction process with an organic acid (preferably acrylic or methacrylic acid) incorporated in the reaction system, to form a semiconductor of the group II to VI (preferably zinc sulfide) doped with an activator (preferably manganese). When, for example, zinc sulfide as the semiconductor doped with manganese as the activator is to be formed, the liquid-phase reaction process reacts manganese acetate and zinc acetate with sodium sulfide in a solvent. This process polymerizes the incorporated organic acid into a polymer, which is chemically bound to the semiconductor to provide part of the energy required for emitting light. COPYRIGHT: (C)1998,JPO

11 citations


Journal Article
TL;DR: In this article, a pulp from softwood, freed almost completely from metals by soaking with SO 2 -water and EDTA, was oxygen bleached in the presence of different alkali sources, e.g., white liquor and oxidized white liquor.
Abstract: Kraft pulp from softwood, freed almost completely from metals by soaking with SO 2 -water and EDTA, was oxygen bleached in the presence of different alkali sources, e.g., white liquor and oxidized white liquor. Sodium sulfide was found to affect the pulp quality adversely, while the influence of sodium thiosulfate was slightly favorable. The total amount of sulfur present during the bleaching appeared almost quantitavely in the spent bleach liquor, mainly as thiosulfate and sulfate. However, a large proportion of the sulfate that was formed during the bleaching could not be derived from thiosulfate. The addition of a substantial amount of manganese suppressed the depolymerization of the cellulose markedly, giving rise to increased selectivity, defined as the viscosity at a given kappa number. When magnesium protector was added in the molar ratio Mg:Mn=10, a further gain in selectivity was obtained, but the rate of delignification was somewhat retarded. Application : manganese removal from the pulp can be done during the oxygen bleaching, yielding a pulp that is easier to further bleach.

10 citations


Patent
05 Feb 1997
TL;DR: In this paper, a method for treating copper-bearing waste acid water produced from production of benzoic sulfimide or saccharin sodium salt is described, which can prevent environmental pollution, and can recover useful chemical substances.
Abstract: The present invention relates to a method for treating copper-bearing waste acid water produced from production of benzoic sulfimide or saccharin sodium salt. Its main steps are: distillation of waste acid water, condensation to recover hydrochloric acid; dissolving residual material with water, regulating pH value and making the obtained A solution react with prepared B solution: filtering, to obtain cuprous chloride and filtrate C; adding sodium sulfide to C solution, filtering to obtain filtrate D; adding active carbon to solution D, fitlering to obtain filtrateE; making filtrate E pass through such processes as concentration, crystallization and drying to obtain sal glauberi. It can prevent environmental pollution, and can recover useful chemical substances.

9 citations


Journal ArticleDOI
TL;DR: In this article, thermal properties of poly(phenylene sulfide amide) (PPSA) prepared using sodium sulfide, sulfur, and thiourea as sulfur sources which reacted with dichlorobenzamide (DCBA) and alkali in polar organic solvent at the atmospheric pressure were studied.
Abstract: Thermal properties of poly(phenylene sulfide amide) (PPSA) prepared using sodium sulfide, sulfur, and thiourea as sulfur sources which reacted with dichlorobenzamide (DCBA) and alkali in polar organic solvent at the atmospheric pressure, were studied. The glass transition temperature (T g ), melting point temperature (T m ), and melting enthalpy (ΔH m ) of the related polymers were obtained by use of differential scanning calorimetry analysis. The results are: T g = 103.4-104.5°C, T,,, = 291.5-304.7°C, and ΔH m = 104.4-115.4 J/g. Thermal properties such as thermal decomposition temperature and decomposition kinetics were investigated by thermogravimetric analysis under nitrogen. The initial and maximum rate temperatures of degradation were found to be 401.5-411.7°C and 437-477°C, respectively. The parameters of thermal decomposition kinetics of PPSAs were worked out to be: activation energy of degradation was 135 to 148 kJ/mol and the 60-s half-life temperature was 360 to 371°C.

Journal ArticleDOI
TL;DR: In this article, a novel synthesis of a new poly(Schiff base sulfide) (PSBS) polymer by nucleophilic displacement polymerization of N, N ′-bis( p -chlorobenzylidine)-4,4′-diaminodiphenyl methane with sodium sulfide in anhydrous condition has been carried out.

Patent
30 Jan 1997
TL;DR: In this article, a hair restoring agent and a cosmetic material base containing one or more kinds of lignins extracted and isolated by usual processes from plant bodies is presented. But the hair restoration agent and the material base are extracted from needle-leaf tree timbers.
Abstract: PROBLEM TO BE SOLVED: To obtain a hair restoring agent and a cosmetic material for hair which are useful for improvement and treatment of the scarce hair and the symptom of loss of hair caused by various factors and excellent in the stability and the safety. SOLUTION: This hair restoring agent and cosmetic material base contains one or more than two kinds of lignins extracted and isolated by usual processes from plant bodies. As the plant bodies, needle-leaf tree timbers, broadleaf tree timbers and grasses are preferable. Extraction and separation of lignins from plant bodies are carried out by dissolving and removing hydrocarbons from plant body tissues by means of the treatment with acids such as hydrochloric acid and sulfuric acid, the treatment with an ammoniacal solution of cupric oxide and the treatment with sodium periodate followed by separating lignins as the insoluble residue and by treating the plant body tissues with inorganic reagents such as alkali agent, sulfurous acid, hydrogensulfite, sulfite, sodium sulfide, sodium hydrosulfide, hydrogen sulfide and chlorinafing agent and with organic reagents such as dioxane, alcohol, phenol and acetic acid to dissolve and separate lignins. COPYRIGHT: (C)1998,JPO

Journal ArticleDOI
TL;DR: In this paper, the hydrogenation inhibitive effect of sodium sulfide (Na2S) on Ti-6% Al-4% V alloy (UNS R56400) in aqueous sulfuric acid solution (H2SO4[aq]) was investigated qualitatively and quantitatively using optical microscopy, x-ray diffraction (XRD), and glow-discharge spectrometry (GDS).
Abstract: The hydrogenation inhibitive effect of sodium sulfide (Na2S) on Ti-6% Al-4% V alloy (UNS R56400) in aqueous sulfuric acid solution (H2SO4[aq]) was investigated qualitatively and quantitatively using optical microscopy, x-ray diffraction (XRD), and glow-discharge spectrometry (GDS). Introduction of Na2S into the electrolyte resulted in an obvious inhibitive effect of hydrogen absorption on as-received (covered with a thin thermal oxide film < 0.5 μm) and abraded specimens (free of thermal oxide film) irrespective of applied current density and operating period. The contrary effect of Na2S on Ti-6% Al-4% V alloy vs ferrous alloys could have resulted from the fact that molecular hydrogen sulfide (H2S), which adsorbed on the titanium surface as on the iron surface, facilitated formation of a thin layer of E titanium hydride (TiH2). TiH2 effectively retarded ingress of hydrogen.

Patent
19 Aug 1997
TL;DR: In this article, a cellulosic fiber mass of viscose rayon is dipped in a sodium sulfide aqueous solution in which sulfur is dissolved, squeezed, dipped in an acid solution, for example, of sulfuric acid.
Abstract: PROBLEM TO BE SOLVED: To obtain an antimicrobial nonwoven fabric which contains cellulosic fibers containing colloidal elemental sulfur, having excellent antimicrobial properties and moisture release and is useful as a medical and living material. SOLUTION: Cellulosic fiber mass of, for example, viscose rayon is dipped in a sodium sulfide aqueous solution in which sulfur is dissolved, squeezed, dipped in an acid solution, for example, of sulfuric acid. The fiber mass is taken out from the acid solution, when the liberation of hydrogen sulfide ceases, washed with water and dried to produce the objective antimicrobial fiber mass containing 0.01-16wt.% of colloidal elemental sulfur. This cellulosic fiber mass is laminated on a polyester spun-bonded nonwoven fabric in an amount of 5-80wt.%, they are integrally entangled with columnar flows of high-pressure water whereby the objective antimicrobial nonwoven fabric with a void volume of 50-95% and a unit weight of 20-100g/m is obtained.

Patent
25 Feb 1997
TL;DR: In this paper, a method of processing white liquor obtained from the causticization stage of a pulp mill is described, in which the sodium hydroxide (6) contained in the white liquor is separated from the white liquid prior to the oxidizing step by diffusion dialysis process.
Abstract: The present invention relates to a method of processing white liquor obtained from the causticization stage of a pulp mill. According to the method, the white liquor, which principally contains sodium hydroxide (6) and sodium sulfide, is oxidized into polysulfide liquor (3), whereby the sodium sulfide is oxidized most advantageously with the help of a catalyst and an oxidizer such as air substantially into sodium polysulfide (7) and sodium thiosulfate. The method according to the invention is characterized in that the sodium hydroxide (6) contained in the white liquor is separated from the white liquor prior to the oxidizing step or from the polysulfide liquor (3) after the oxidizing step either entirely or partly by means of a diffusion dialysis process (4). The invention is further characterized in that the sodium hydroxide (6) separated from the white liquor is returned to the chemical circulation of the pulp mill.

Patent
08 Jul 1997
TL;DR: In this article, an aq. soln. containing either one or both of a ferrous salt and a ferric salt was used as a decolorant flocculant to treat color substance-containing waste water.
Abstract: PROBLEM TO BE SOLVED: To provide a treatment method centering around the decoloration treatment of color substance-containing waste water not requiring tertiary treatment high in treatment cost and using active carbon or an oxidizing agent, not restricted by the kind of a dye, certainly removing a color substance in waste water, not leaving iron ions or SS in waste water after treatment, lowering the water content of a dehydrated cake, improving the releasability of a cake from filter cloth and bringing the pH of the cake to about 7. SOLUTION: An aq. soln. containing either one or both of a ferrous salt and a ferric salt and an aq. soln. containing either one or both of sodium sulfide and sodium hydrosulfide are reacted to form iron sulfide, which is, in turn, used as a decolorant flocculant to treat color substance-containing waste water. Since iron sulfide is extremely good in adsorbability, easy to increase in particle size and excellent from an aspect of the formation, flocculation and sedimentation of floc, the remaining of iron ions or SS in waste water after treatment can be prevented. Further, by together using a polymeric flocculant, treatment capacity can further be enhanced.

Patent
21 Jan 1997
TL;DR: In this article, the objective is to obtain a high-quality disulfide in high yield useful as a raw material for various synthetic chemicals such as a surfactant, a dye, a medicine, an agrochemical, etc.
Abstract: PROBLEM TO BE SOLVED: To obtain a high-quality disulfide in high yield useful as a raw material for various synthetic chemicals such as a surfactant, a dye, a medicine, an agrochemical, etc., including a raw material for various additives required for producing rubber, a plastics, etc. SOLUTION: This disulfide as the objective compound, such as dicyclohexyl disulfide of the formula is obtained by reacting a monochloro-substituted compound (e.g. chlorocyclohexane) with an alkali metal sulfide (e.g. sodium sulfide) or a mixture containing it in the presence of a solvent (e.g. a 1-3C aliphatic alcohol such as methanol) and an alkali metal hydroxide (e.g. sodium hydroxide) at 72-110 deg.C inner temperature under normal temperature to 1.9kg/cm G. The amounts of the reagents used are preferably 0.2-0.4mol of the alkali metal hydroxide and 0.8-3.0mol of the solvent based on 1mol of the monochloro- substituted compound.

Journal ArticleDOI
TL;DR: In this article, it was shown that after such treatment the sulfur atoms are almost exclusively bonded only to gallium atoms, conditioned by the electrostatic interaction of sulfur ions in the solution with the surface ions of the crystal lattice of the semiconductor.
Abstract: X-ray photoelectron spectroscopy has been used to study chemical bonds which appeared on the (110) surface of GaAs after cleavage of the crystal in solutions of sodium sulfide in different alcohols. It has been shown that after such treatment the sulfur atoms are almost exclusively bonded only to gallium atoms. This is conditioned by the electrostatic interaction of sulfur ions in the solution with the surface ions of the crystal lattice of the semiconductor.

Patent
07 Jan 1997
TL;DR: In this paper, a heavy metal solution in which heavy metals in incineration ash are eluted is mixed with sodium sulfide, etc., and is pH-adjusted to precipitate and separate a part of the heavy metals as sulfides.
Abstract: PURPOSE: To classify and recover heavy metals intended to be separated, classified and recovered as sulfides with high purity and high recovery rate always without increasing sulfur component content in treated waste water even when kinds and amounts of heavy metals in incineration ash which is the object to be classified and recovered vary from day to day. CONSTITUTION: A heavy metal solution in which the heavy metals in incineration ash are eluted is mixed with sodium sulfide, etc., and is pH-adjusted to precipitate and separate a part of the heavy metals as sulfides. After separation of precipitates, the solution is mixed with sodium sulfide, etc., again and is pH- adjusted to precipitate and separate a part or all of the heavy metals as sulfides. At this time, the amounts of the respective heavy metals in the heavy metal solution are obtained by analysis and the amounts of heavy metals to be precipitated and separated are previously calculated therefrom and amount of sodium sulfide, etc., to be added is set as amount of sulfer by making chemical equivalent of the amounts of the calculated heavy metals as a reference.

Journal Article
TL;DR: In this article, a variety of synthetic and mill liquors (sodium carbonate, kraft white liquor, oxidized white liquor and soda white and green liquors) were evaluated as replacements for sodium hydroxide during oxidative extraction of hardwood and softwood pulps.
Abstract: A variety of synthetic and mill liquors-sodium carbonate, kraft white liquor, oxidized white liquor, and soda white and green liquors-were evaluated as replacements for sodium hydroxide during oxidative extraction (EO and EOP) of hardwood and softwood pulps. These alkalis were screened based on the rate of decomposition of hydrogen peroxide, which was significant in synthetic kraft white liquor in unsuitable for oxidative extraction because sodium sulfide rapidly decomposes hydrogen peroxide. The soda-mill liquors contained transition metals that hastened peroxide decomposition. Removal of transition metals is an option, and magnesium salt was a better scavenger than DTPA. Peroxide decomposition in the other synthetic liquors was negligible. Pulps extracted with 100% sodium carbonate required excessive chlorine dioxide to achieve acceptable brightness (86-87% ISO). The study concludes that mixtures of sodium carbonate and sodium hydroxide (50/50 or 40/60) or synthetic oxidized white liquor are effective substitutes for caustic soda in oxidative extraction. Application : caustic soda is a byproduct of chlorine production, so its cost is expected to increase as pulp mills phase out their use of chlorine. This study evaluates alternatives to caustic soda for oxidative extraction of pulps during multistage bleaching.

Patent
10 Jun 1997
TL;DR: In this paper, the waste Ni catalyst is mixed with water and the mixture is crushed using a ball mill, and then a decoction consisting mainly of the MO and V components and a decocction residue containing Ni, Co, Mo and V are obtained.
Abstract: PROBLEM TO BE SOLVED: To enable Ni, Co, Mo and V to be recovered at a high yield from a waste Ni catalyst by using a method such as wet crushing, water leaching or sulfuric acid spraying by flame. SOLUTION: Waste Ni catalyst is mixed with water and the mixture is crushed using a ball mill. The waste Ni catalyst completely undergoing this wet crushing process is subjected to a water leaching process 2 and consequently, a decoction consisting mainly of the MO and V components and a decoction residue containing Ni, Co, Mo and V are obtained. Ni and Co contained in the water decoction residue are dissolved by heating the water decoction residue at a high temperature using a mixture of sulfuric acid and water (cooking 3). After adjusting the pH value of the obtained solution (4), a sulfiding agent such as sodium sulfide or sodium hydrogen sulfide is added to Ni, Co and Mo contained in the filtrate. Thus it is possible to recover Ni, Co and Mo as a mixed sulfide at an yield of 98%. On the other hand, Mo and V are contained as main components in the liquid after the water leaching step 2, and are separated and recovered using a routine process.


Patent
03 Jun 1997
TL;DR: In this paper, a trihaloaromatic compound was used to obtain a polyurethane resin with specific viscosity characteristics, capable of continuously coating a metal without causing the resin breakage and good in heat and chemical resistances, strength and electrical characteristics.
Abstract: PROBLEM TO BE SOLVED: To obtain the subject resin, having specific viscosity characteristics, capable of continuously coating a metal without causing the resin breakage and good in heat and chemical resistances, strength and electrical characteristics by polymerizing an alkali metallic sulfide with a dihaloaromatic compound in the presence of trihaloaromatic compounds. SOLUTION: The polymerizing reaction of an alkali metallic sulfide (e.g. hydrous sodium sulfide) and a dihaloaromatic compound (e.g. p-dichlorobenzene) is carried out in the presence of a trihaloaromatic compound (e.g. 1,2,4- trichlorobenzene) in a solvent such as N-methylpyrrolidone at 220 deg.C temperature in a nitrogen atmosphere for 5hr to thereby afford the objective resin, having 50-3000Pa.s melt viscosity η200 measured at 310 deg.C and 200/sec shear rate and the ratio R (η200 /η200 ) of the melt viscosity η200 to the melt viscosity η1200 measured at 310 deg.C and 1200/sec shear rate satisfying the formula. The resin is capable of stably and continuously coating a metal without causing resin breakage and without cracking a coating layer due to heat treatment and has high heat, olefin and chemical resistances, flame retardance, low-temperature physical properties, electrical insulating properties and strength.

Patent
31 Mar 1997
TL;DR: In this article, a method for producing polysulfide cooking liquor, capable of improving oxidation selectivity to sodium sulfide according to a lime mud method and capable of increasing the productivity of poly sulfide by perceiving a lime-mixture method in producing poly sulfide cooking liquid, was proposed.
Abstract: PROBLEM TO BE SOLVED: To provide a method for producing polysulfide cooking liquor, capable of improving oxidation selectivity to sodium sulfide according to a lime mud method and capable of increasing the productivity of polysulfide by perceiving a lime mud method in producing polysulfide cooking liquor in which it is possible to be carried out through simple, additional equipment alteration without steep change in a conventional process for recovering KP(kraft process) chemicals. SOLUTION: The method comprises graduating green liquor from a black liquor- recovering process in the cooking process of a kraft process or a polysulfide method into a solution containing sodium sulfide in a low concentration and a solution containing sodium sulfide in a high concentration, causticizing the solution containing sodium sulfide in a low concentration by adding lime formed in a calcining kiln and containing calcium oxide as a principal ingredient, adding the solution containing sodium sulfide in a high concentration to the causticized solution or separating lime mud formed and containing calcium carbonate as a principal ingredient, followed by dispersing lime mud into the solution containing sodium sulfide in a high concentration, and oxidizing sodium sulfide content with oxygen-containing gas in the presence of a transition metal compound to convert the sodium sulfide component into polysulfide.

Patent
28 Apr 1997
TL;DR: In this paper, a metal collecting agent having an aryl group and a carbodithio group was introduced by replacing an active hydrogen atom bonded with nitrogen atom of polyamine, and a sodium sulfide.
Abstract: PROBLEM TO BE SOLVED: To efficiently remove metals contained in a waste water or the like by preparing from a metal collecting agent having an aryl group and a carbodithio group, which are introduced by replacing an active hydrogen atom bonded with nitrogen atom of polyamine, and a sodium sulfide. SOLUTION: This waste water treating agent, which is improved in the precipitability of floc and is capable of reducing water content in the floc, is prepared by blending the metal collecting agent having the aryl group and the carbodithio group, which are introduced by replacing the active hydrogen bonded with nitrogen atom of the polyamine, with the sodium sulfide. In such a case, the replacing ratios of the aryl group and the carbodithio group introduced into the metal collecting agent as the substituted groups are respectively 5-20% and 50-90% of total replaceable active hydrogen atoms, which are capable of bonding with nitrogen atoms of the original polyamine. Further, the volume ratio of the introduced aryl groups to the carbodithio groups is controlled to 1:3 to 1:1.

Patent
19 Nov 1997
TL;DR: A process for constant-temp polymerization of food-class sodium trimetaphosphate includes such steps as reaction of phosphoric on sodium sulfide, purifying, addition of sodium carbonate, neutralizing filter, fusion, suddenly cooling, rolling, crushing, and repolymerization to obtain a stable quality, less consumption and high productivity.
Abstract: A process for constant-temp. polymerization of food-class sodium trimetaphosphate includes such steps as reaction of phosphoric on sodium sulfide, purifying, addition of sodium carbonate, neutralizing filter, fusion, suddenly cooling, rolling, crushing to obtain sodium hexametaphosphate, and repolymerization to obtain sodium trimetaphosphate. Its advantages are stable quality, less consumption and high productivity.

ReportDOI
01 Feb 1997
TL;DR: In this article, the results and lessons learned from full-scale implementation of the FS/SS process were presented, which reduced the volume of sludge generated by 20 to 30 percent, reduced the amount of treatment chemicals, and resulted in over $35,000 annual savings.
Abstract: : The ferrous sulfate/sodium sulfide (FS/SS) process is a treatment technology for the reduction of hexavalent chromium and precipitation of heavy metals in industrial wastewater treatment plants (IWTPs). When the ferrous ion, as ferrous sulfate, is mixed with sulfide, the hexavalent chromium is rapidly reduced to its trivalent state at a neutral pH and then precipitated. FS/SS technology can be used to replace the current hydroxide treatment chemistry. This report presents the results and lessons learned from full-scale implementation of FS/SS. The FS/SS treatment process reduced the volume of sludge generated by 20 to 30 percent, reduced the amount of treatment chemicals, and resulted in over $35,000 annual savings. Furthermore, metal sulfides tend to be two to three orders of magnitude less soluble than their corresponding metal hydroxides. This gives cleaner effluent, which helps the facility meet environmental requirements. Further benefits include the removal from the shop area of the high pressure sulfur dioxide cylinder (used in the hydroxide process), a faster and more reliable chrome reduction method, neutral pH operation that extends tank and equipment life, and less acid and caustic chemicals stored on the shop floor. As Navy activities do more with less, the FS/SS process can help meet increasingly stringent standards.

Journal ArticleDOI
TL;DR: In this article, N-Benzyl-3-thia-9-aza-bicyclo[3.3.1]nonan-7-one has been prepared from methyl 4-bromocrotonate by reaction sequence involving sodium sulfide, benzylamine, and Dieckmann condensation.
Abstract: N-Benzyl-3-thia-9-aza-bicyclo[3.3.1]nonan-7-one has been prepared from methyl 4-bromocrotonate by reaction sequence involving sodium sulfide, benzylamine, and Dieckmann condensation. Some spectral and chemical properties of this system are also reported.