Showing papers on "Sodium sulfide published in 1999"

Raman Spectroscopy Study of the Reaction between Sodium Sulfide or Disulfide and Sulfur: Identity of the Species Formed in Solid and Liquid Phases.

Abstract: The reactions of sodium sulfide or disulfide with sulfur, when heated, are examined through Raman spectroscopy. It is shown that whatever the composition of the mixtures, the solid sodium sulfide or disulfide transforms into the crystalline α-Na2S4 phase in a first step, with α- or β-Na2S2 as an intermediate. The reaction, which proceeds when the sulfur melts, is assumed to be related to the polymerization−depolymerization mechanism responsible for the formation of smaller rings and sulfur chains in molten S8. This confirms the strong reactivity of the radical sulfur chain molecules. This solid α-Na2S4 formed may further react around 200 °C with Na2S in excess. This solid-state reaction leads to the formation of β-Na2S2. It is shown that, after the liquid of composition Na2S4 is heated above 400 °C, a glass is formed upon cooling. Annealing this glass around 124 °C yields a new γ-Na2S4 crystalline phase where the S42- anions have a smaller torsion angle. This new phase is metastable and transforms into th...

Method of removing mercury from a mercury-containing flue gas

Abstract: A method of removing mercury from a mercury-containing flue gas, especially flue gas from a refuse incinerator, is provided. The mercury-containing flue gas may also contain dust, further heavy metals, and further gaseous noxious gas components. The mercury, using an alkali sulfide solution, especially sodium sulfide solution, and in particular sodium tetrasulfide solution, is converted to mercury sulfide and the mercury sulfide is precipitated out via a dust separator. The alkali sulfide solution is introduced into the flue gas accompanied by the simultaneous addition of heat.

Method for preparing nanometre material by solid phase chemical reaction

Abstract: The method for preparing nanometer material by using solid phase chemical reaction is characterized by grinding solid metallic salt together with sodium hydroxide, sodium sulfide, sodium halide, oxalic acid and 8-hydroxyquinoline to obtain the nanometer-level oxide, sulfide, halide, oxalate and oxinate. said invented method is simple and convenient for operation, and its particle grain size is uniform.

22 – Cellulose Plastics

Abstract: This chapter mainly focuses on cellulose plastics. Cellulose is the most abundant of naturally occurring organic compounds for the chief constituent of the cell walls of higher plants, it comprises at least one third of the vegetable matter of the world. The cellulose content of such vegetable matter varies from plant-to-plant. For cotton, linters are the short fibers removed from cotton seeds after the long fibers for use in textiles have been taken off by the process of ginning. Cellulose is produced from wood via wood pulp. A number of processes are used in which the overall effect is the removal of the bulk of the non-cellulosic matter. The most widely used are the sulfite process, which uses a solution of calcium bisulfite and sulfur dioxide, the soda process using sodium hydroxide, and the sulfate process using a solution of sodium hydroxide and sodium sulfide. The cellulose esters are useful polymers for the manufacture of plastics. The most important of the esters is cellulose acetate. This material has been extensively used in the manufacture of films, molding and extrusion compounds, fibers and lacquers. As with all the other cellulose polymers, it has become of small importance to the plastics industry compared with the polyolefins, PVC, and polystyrene. Despite their higher cost, cellulose acetatebutyrate and cellulose propionate appear to have retained their smaller market because of their excellent appearance and toughness. Important characteristics of cellulose are water-white transparency of basic composition, but capable of forming highly attractive multicolored sheeting, rigidity, reasonable toughness, and capable of after-shrinkage around inserts.

Method for treating drainage containing arsenic and other heavy metals

Abstract: PROBLEM TO BE SOLVED: To remove drainage containing arsenic and other heavy metals economically and efficiently by a method in which a sulfurizing agent of a specific pH value is added into drainage containing arsenic and other heavy metals, iron (III) ions are added with sulfide deposits left in the water, and the produced precipitates are separated. SOLUTION: Dilute drainage in which the concentration of each component of arsenic and other heavy metals is, for example, 100 mg/liter or below is added alkali, if the drainage is acidic, in order to adjust its pH at 7 or above, added with a sulfurizing agent, and stirred. Hydrogen sulfide, sodium sulfide, sodium hydrogen sulfide, and others can be used as the sulfurizing agent, and sodium hydrogen sulfide (NaHS) is used preferably. The amount of the agent to be added is controlled to be twice or below the necessary equivalent to sulfurize the components in liquid. After that, the liquid is added with iron (III) ions with the sulfide deposits left in the liquid. In this way, the produced precipitates are removed from the liquid, and the purification of the drainage is finished.

Material for fixing hazardous substance

Abstract: PROBLEM TO BE SOLVED: To provide material for fixing hazardous substances for stably and inexpensively fixing heavy metals for a long time and enable fixture of not only heavy metals but also negative ions such as a chromate ion a bichromate ion, a hologen ions such as a chlorine ion, fluorine ion and the like, an aisenate ion, a phosphate ion, a nitrite ion, a nitiate ion and the like which are difficult to fix by the prior arts. SOLUTION: At least one of substances having re-hydration characteristic obtained by heating treatment of a calcium sulphoaluminate hydrate and by heating treatment of calcium aluminate hydrate is contained as a primary constituent. Or, a mixture of at least one of them and at least one kind selected from quick lime, slaked lime, gypsum, blast furnace water-granulated slag, Portland cement, iron sulfate, iron chloride, sodium hydrosulfide, sodium sulfide, thiourea, calcium polysulfide is more preferable. COPYRIGHT: (C)2000,JPO

Method for reduction of desulfurized waste residue, phosphogypsum or natural gypsum

Abstract: The present invention uses a composite compound formed from iron, nickel, magnesium and sodium as catalyst, and when the temperature is highter than 650 deg.C, it can reduce more than 95% of calcium sulfate into calcium sulfide, then the obtained calcium sulfide can be further converted into sodium sulfide, sodium thiosulfate or sulfur. Said invented method lowers the required temp. in the reduction stage, reduces the energy consumption and loss of equipment, and can obtain several kinds of product, and is favourable for recovering sulfur resource from desulfurized waste residue, phosphogypsum and natural gypsum.

METHOD FOR MEASURING DEGREE OF NEUTRALIZATION OF pH INDICATOR PIGMENT ADHESION TYPE CONCRETE

Abstract: PROBLEM TO BE SOLVED: To measure the degree of neutralization of concrete without causing trouble from an aspect of aesthetic appearance by applying a pH indicator developed in color to indicate pH to concrete to measure a degree of neutralization and decoloring the pigment bonded to concrete by a decolorant. SOLUTION: A pH indicator which develops a color capable of being decolored by a decolorant to indicate pH is used in a form of an aq. soln. or ethanol soln. and selected, for example, from thymolphthalein, metacresol purple, cresol red or the like and a plurality of these indicators may be together used. When these indicators are used, pigment is bonded to concrete to damage the surface aesthetic appearance of concrete. Then, the bonded pigment is decolored by a decolorant. As the decolorant, sodium dithionite, sodium hydrogen sulfide or sodium sulfide is used as a reducing agent and sodium hypochlorite, calcium hypochlorite or sodium chlorite is used as an oxidizing agent and these compds. are used as an aq. soln. with appropriate concn.

Process and apparatus for controlling and optimizing the process of chemical recovery during cellulose production

Abstract: A digestion chemicals recovery process for a sulfite or sulphate pulp mill a) measures at least one continuous electromagnetic radiation spectrum (100nm - 400micron), for the process, b) evaluates indices PC1...PCn for the principle components of the liquor, and c) sets up a control model using the calculated values PC1...PCn , plus laboratory / plant measurements. A digestion chemicals recovery process for a sulfite or sulphate pulp mill uses a process control logic system or a control model. The continuous electromagnetic radiation spectrum is measured by either absorption, emission, or Raman spectroscopy. The laboratory / plant measurements comprise: Liquor temperature, concentration, pH, conductivity and flow rate. Preferably data from a number of spectrometers sampling at different stages of the wet process is analyzed e.g. via Fourier and Kubelka Munk techniques. The control system is able to assess the validity of individual measurements before inputting them to the control model; it may use neural networks or fuzzy logic. In the Sulphate Process, the recovery system uses concentration data for active alkali, total sulfide, sulphate, sodium sulfide, sodium carbonate and sodium hydroxide. The Sulfite Process, recovery requires concentration data for sulfur dioxide, bisulfite, sulfite, thiosulfate, sulfate, dead-burnt magnesia and active magnesium oxide. A CLAIM for the equipment required to operate the process includes: At least one spectrometer, a computer for evaluation of PC1...PCn from the continuous spectra and for inserting reference variables PC1...PCn , and optionally the discrete physical and / or chemical properties as process parameters into the process control logic or the control model.

Method of flotation of nonferrous ores

Abstract: FIELD: flotation concentration of minerals; applicable in processing of copper-nickel and copper-molybdenum ores containing iron sulfides. SUBSTANCE: method includes grinding of ore in natural medium; pulp conditioning with sodium or ammonium fluosilicate, iron complexing hydroxy compound, with maintaining optimal relationship Between oxidizing potential and concentration of hydrogen ions pH in compliance with Eh=272-59 pH in processing of pyrrhotine-containing ores, or Eh=505-59 pH in processing of pyrite-containing ores; subsequent introduction into pulp of sodium sulfide by maintaining Eh= 272-59 pH. In so doing, in processing of pyrite-containing ores containing in pulp liquid phase of no copper cations, prior to supply of sodium, or ammonium fluosilicate, copper sulfate is added. Its consumption is regulated by optimal relationship between potential of argentite electrode and hydrogen ion concentration of Ecu=477-59 pH. EFFECT: elimination of harmful effect of iron hydroxy compounds in pulp liquid phase and on surface of sulfide minerals to ensure higher recovery of valuable minerals. 2 cl, 4 dwg

Melt-blown nonwoven fabric made of polyarylene sulfide and its production

Abstract: PROBLEM TO BE SOLVED: To produce a nonwoven fabric excellent in heat and chemical resistances, flame retardance and mechanical properties by producing a melt blown nonwoven fabric from a polyarylene sulfide having a non-Newtonian coefficient within a specific range and a branched or a crosslinked structure as a raw material SOLUTION: This melt blown nonwoven fabric is produced by carrying out a polymerizing reaction in a polar solvent containing 100 mol% of an alkali metal sulfide such as sodium sulfide, a dihaloaromatic compound such as p-dichlorobenzene and 0001-06 mol% of a polyhaloaromatic compound having >=3 halogen substituent groups in one molecule, eg 1,2,4-trichlorobenzene added thereto to provide a polyarylene sulfide having 105-120 non-Newtonian coefficient, then carrying out a thermal oxidizing crosslinking treatment of the resultant polyarylene sulfide at 160-260 degC in a mixed gas of air or oxygen with an inert gas, subsequently melt kneading and discharging the polyarylene sulfide from a nozzle at 300-360 degC, drawing discharged fibers in a high-temperature gas at 300-360 degC, providing ultrafine fibers and subsequently collecting the resultant ultrafine fibers in a collecting part The average fiber diameter of polyarylene sulfide fibers forming the nonwoven fabric is <=10 μm

Method for producing hydrogen sulfide

Abstract: The production method of hydrogen sulfide is characterized by utilizing by-product produced in the course of production of some aromatic intermediates-specific waste sulfuric acid aqueous solution, and making one react with specific sodium sulfide aqueous solution or slurry liquid phase to produce hydrogen sulfide. When preparing specific sodium sulfide aqueous solution or slurry liquid, the required solid sodium sulfide can be industrial sodium sulfide, but better use sodium sulfide calcinate obtained by heat reduction of anhydrous sodium sulfate, and water used can be clean water, but better use the waste water discharged in the course of production of some aromatic intermediates and already regulated to basicity.

Method for removing hydrogen sulfide from natural gas

Abstract: A process for removing hydrogen sulfide from a natural gas stream. Use is made of heat and pressure to induce spontaneous combustion of sodium sulfide. The latter is formed by contacting the stream with an alkali earth salt and subsequently treating the so formed sodium sulfide with sodium bicarbonate to form sodium sulfate. The sodium sulfate is a useful precursor in further chemical processes.

Nucleophilic Displacement Polymerlzation of N,N'-BIS(p-Chlorobenzylidine)-4, 4'-Diaminodiphenyl Ether with Sodium Sulfide

Abstract: A novel poly(Schiff-base sulfide) polymer was synthesized by nucle-ophilic displacement polymerization of N,N'-bis(p-chlorobenzylidine)-4, 4'-diaminodiphenyl ether with sodium sulfide in anhydrous condition. The resulting polymer was soluble in some aprotic solvents having inherent viscosity of 0.18 dL/g in dimethylacetamide at 30°C. The monomer and the polymer were characterized by elemental analysis, infrared, and 1H NMR (nuclear magnetic resonance) spectroscopy. The thermal characteristics of the polymer were also studied by thermo-gravimetric analysis and differential scanning calorimetry. The temperature of 10% weight loss, glass transition temperature (T g). and crystalline melting point (T m) of the polymer were found to be 420, 91.89, and 38575°C respectively.

Phosphor and its production

Abstract: PROBLEM TO BE SOLVED: To obtain a nano-crystalline phosphor which can be excited at a low voltage and fluoresces a green or red color. SOLUTION: There is provided a nano-crystalline phosphor comprising a nano-structure crystal comprising a fluorine-charge-compensated terbium or europium-activated zinc sulfide and having a particle diameter of 2-5 nm. To produce the nano-crystalline phosphor, zinc acetate and sodium sulfide, terbium nitrate (or europium nitrate), and sodium fluoride are mixed in such amounts that the terbium (or europium) is present in an amount of 0.5-5 mol.% based on the zinc, and the fluorine is present in an amount of 1.5-15 mol.%, and the mixture is subjected to a liquid-phase reaction to coprecipitate nano-structure crystals of zinc sulfide doped with a fluorine-charge-compensated terbium (or europium). By compensating the difference between the charges of terbium or europium and zinc by introducing fluoride ions, the luminance characteristics can be markedly improved.

Studies in the Reaction–Separation Method for the Preparation of Barium Chloride from Barite Using Ion Exchange

Abstract: We report the application of an ion-exchange process as a reaction-separation strategy for the preparation of barium chloride from barite ore and sodium chloride. Experimental studies were carried out to evaluate the process efficiency and purity/yield of barium chloride using a strong acid cation-exchange resin, Tulsion T-42. The effects of various process parameters such as concentration of barium sulfide and concentration of sodium chloride were investigated, and optimization of the experimental variables was attempted. The results indicate the developed strategy to be attractive and an alternative route to existing processes. The methodology developed has large potential for the inorganic chemical process industry in general.

Removal of mercury in liquid hydrocarbon

Abstract: PROBLEM TO BE SOLVED: To efficiently remove mercury in liquid hydrocarbon through simple operation by bringing liquid hydrocarbon containing mercury into contact with a substance that can ionize elementary mercury and a specific sulfur compound and increase the operability in the petroleum refining and the like. SOLUTION: A liquid hydrocarbon containing mercury, for example, crude oil or the like is brought into contact with a substance that can ionize elementary mercury and is selected from iron sulfate, iron sulfide, iron oxide, copper oxide and crude oil tank sludge and a sulfur compound selected from the formula: MM'S (M and M' are each H, an alkali metal or an ammonium group), for example, hydrogen sulfide, sodium sulfide and sodium hydrogen sulfide to reduce the mercury level down to <=1 W/V ppb. In a preferred embodiment, the sulfur compound is an aqueous solution containing this sulfur compound.

Hazardous substance-fixing material

Abstract: A hazardous substance-fixing material capable of fixing heavy metals stably over a long period of time, which comprises as a main component at least one of substances being capable of hydrating obtained by heating a calcium sulfoaluminate hydrate or a calcium aluminate hydrate. A mixture of the at least one substance with one or more of quick lime, slaked lime, gypsum, water granulated blast furnace slag, portland cement, iron sulfate, sodium hydrosulfide, sodium sulfide, thiourea and calcium polysulfide is more preferred. The hazardous substance-fixing material can fix not only a heavy metal, but also an anion such as chromic ion, chloride ion or the like which has been difficult to fix by use of a conventional method.

Polyarylene sulfide and its production

Abstract: PROBLEM TO BE SOLVED: To obtain a polymer having reduced tendency toward burr formation and high strengths by adding a branching agent and, optionally, a polymerization solvent and/or a sulfur source to a prepolymer having a specified melt viscosity and a solution or slurry in which the prepolymer has been dissolved or dispersed and subjecting the entire mixture to polymerization at a specified temperature. SOLUTION: To a polyarylene sulfide prepolymer having a melt viscosity of 0.05-0.25 dl/g and a solution or slurry in which the prepolymer has been dissolved or dispersed, added is 0.1-1.5 mol.%, based on the number moles of the repeating units of the prepolymer, branching agent such as trichlorobenzene and, optionally, a polymerization solvent, such as N-methyl-2-pyrrolidone, in an amount to give a molar ratio of 2-20 or 0-10 mol.% sulfur source such as sodium sulfide. The resultant mixture is subjected to polymerization at 270-290 deg.C under conditions not causing phase separation to obtain a polyarylene sulfide satisfying the relationships: N>=0.3×log10 (ηm )+0.5; N>=1.10; F>=57×log10 (ηm )-60; and R>=40. In the relationships, F is the bending strength (MPa); N is the branching index; and ηm is the melt viscosity (Pa.s).

Immersion test of the Ag−Pd−Cu alloy system

Abstract: Silver-palladium alloys are widely used as substitutes for gold alloys. Pure silver, three Ag−Cu eutectics, three Ag−Pd solid solutions and nine Ag−Pd−Cu ternary alloys were prepared. The specimens were immersed in three kinds of solutions, Ringer’s, 0.1% sodium sulfide, and 1% lactic acid solutions. The change of the reflectance and the color was examined using CIE, Yxy notation. The reflectance of polished specimens was maximum in the pure silver specimen. It decreased with the decrease of silver content, or with the increase of palladium content. In Ringer’s solution, only Ag−Pd eutectic alloys decreased the reflectance. In sodium sulfide sulution, all of the specimens decreased the reflectance, but pure Ag and Ag−Pd entectics showed the largest decrease. In the lactic acid solution, no reflectance and color change was observed. However, a weight loss was observed in pure silver, Ag−Cu eutectics and one high-copper ternary alloy. Even if the specimen changed color visually to dark yellowish, the measured chroma is still small and remained achromatic.

Thermodynamics of reactions between oxide glass melts and gases : II. Solubility of gases containing sulfur (SO3, SO2, and S2)

Abstract: The equilibrium between sulfur-containing gases (SO 3 , SO 2 , and S 2 ) and oxygen is considered. It is demonstrated that, at a very low partial pressure of oxygen and temperatures above 1000°C, the gas phase consists predominantly of SO 2 and S 2 . The reactions of the dissolution of SO 2 and S 2 in silicate glass melts with the formation of sulfates and sulfides are formulated in the general form. It is shown that the main component SiO 2 of silicate melts virtually does not participate in the reaction of the dissolution of SO 2 and S 2 . With due regard for the foregoing, the equations that relate the mole fractions of dissolved sulfate x s-t and sulfide x s-d to the temperature, the concentration of reacting oxide, and the product P SO2 P O2 0.5 (upon formation of sulfates) or P S2 0.5 P O2 0.5 (upon formation of sulfides) are derived. These equations are applied to the thermodynamic analysis of the data available in the literature on the solubility of sulfatic and sulfidic components in silicate glass melts. It is found that the enthalpy ΔH of formation of sodium sulfate in sodium silicate melt significantly less than the standard enthalpy ΔH 0 . Upon formation of sodium sulfide in sodium borosilicate melt, the enthalpy of reaction is positive, whereas the standard enthalpy is negative. This is accounted for by the fact that the enthalpies of dissolution of sodium oxide and sodium sulfate (sulfide) in the studied melt affect the enthalpy of formation ΔH. A strong influence of x N a 2O on the value of x NaSO4 is explained by the fact that an increase in x Na2O is accompanied with a sharp increase in the activity coefficient γ Na2O . The activity coefficients γ NaSO4 in the Na 2 O-SiO 2 melts are calculated from the available experimental data. The behavior of Na 2 SO 4 in these melts is characterized by noticeable positive deviations from ideal. It is revealed that the dependence of the total concentration of sulfatic and sulfidic sulfur components on the partial pressure P O2 exhibits a minimum. This conclusion is in agreement with the experimental data. The assumption is made that iron sulfide can be formed in glass melts upon bleaching under reducing conditions.

Electric double-layer capacitor and electrolyte

Abstract: PROBLEM TO BE SOLVED: To enable increasing the capacitance of a capacitor using an electrolyte of reducing ion electrolyte, in an electric double-layer capacitor. SOLUTION: An electric double-layer capacitor is provided with a carbon electrode and an electrolyte, and a reducing ion electrolyte wherein ammonium iodide is used, is used as the electrolyte. Also, sodium sulfide, potassium sulfide, lithium sulfide, sodium iodide or potassium iodide is used. The density of the reducing ion electrolyte is set at 0.1 mol/l (liter) or higher, and the active carbon having a specific surface area of about 2,000 m /g is used as the material of the carbon electrode. In addition, although the reducing ion density has been obtained using a single material, but a plurality of materials may also be used together.

Preparation method for dimethyl disulphide

Abstract: A process for preparing dimethyldisulfure includes such technological steps as adding excessive sulfure to sodium sulfide's aqueous solution to obtain Na2S2 solution, dripping dimethyl sulfate to obtain the mixed liquid of dimethyl disulfure and dimethyl polysulfure, reaction on solution of sodium sulfide whose consumption is 1/3 that of the first addition, ordinary-pressure distilling and rectification. The mol ratio of sodium sulfide, sulfure and dimethyl sulfate is (1-1.5) : (1-1.7) : 1 : (1.1 : 1.4 : 1 is optimum).

Method of manufacturing heat-resistant russia upper leather from wet- saline conservation cattle skin

Abstract: FIELD: leather industry. SUBSTANCE: invention concerns chrome-dubbing of Russia leather. Skins are soaked in sodium sulfide solution for 16-18 hr, after which integrated process is performed involving unhairing liming in sodium sulfate and calcium hydroxide solution to which sodium carbonate was added. Liming liquid is strengthened by single addition of calcium hydroxide 12 hr after the beginning of liming process and twofold addition of sodium sulfide 2 and 12 hr after the beginning of liming process. Resulting offal is then delimed with ammonium sulfate for 1 hr 40-45 min at ammonium sulfate concentration 2.5-3.8% based on the weight of offal at fatty acid index 1.5-2.0. Skins are bated with protosubtelin for 10-15 min, pickled in sulfuric acid solution, chrome-tanned, and neutralized with sodium bicarbonate at its concentration 2.0-3.0% and fatty acid index 1.5-2.0. Further, skins are dyed in a dye containing direct black (0.8%) and water-soluble nigrosine (0.8%) for 1.5-2.0 hr at fatty acid index 1.2- 2.0, dubbed with natural and synthetic fats, hydrophobized, after- tanned, soaked and dried to leather moisture 25-28% while simultaneously applying additional soaking. EFFECT: enhanced process efficiency and improved quality of leather. 9 cl