Abstract: A method of regenerating an activated carbon catalyst which is used in the production of polysulphide liquor. In the method, the catalyst is washed with a washing liquid in order to remove the sediment accumulated in the catalyst. According to the present invention, in this case, the activated carbon catalyst is regenerated most suitably by bringing it to a multi-stage washing which comprises at least one washing step in which the washing liquid used comprises sodium sulphide, and one washing step in which acidic washing liquid is used. The sulphur precipitate is peeled off using sodium sulphide, and the iron and other metals can be effectively removed by using an acidic washing, without damaging the catalyst.

Abstract: A battery electrode, a composition for a catalyst layer of a battery electrode, and a battery having excellent characteristics at low cost. The battery electrode includes a catalyst layer containing a non-platinum catalyst and platinum particles not being carried on the non-platinum catalyst, wherein a content of the platinum particles per unit area of the battery electrode is 0.0010 mg/cm2 or more and 0.1200 mg/cm2 or less.

Abstract: The processes can comprise feeding a furnace with a raw material. These materials can contain impurities and valuable metals (base metals, precious metals, platinum group metals, minor metals). The processes can allow the volatilization of arsenic and indium contained therein. Before volatilizing the material, composition of the material is optionally modified so as to obtain a ratio % S/(% (Cu/2)+% Ni+% Co) of about 0.5 to about 2. The processes can comprise feeding a melting device with the depleted material, and with a source of carbon in order to obtain a multi-layer product and an off gas. Before melting the depleted material, the depleted material composition is optionally modified so as to obtain a ratio % S/(% (Cu/2)+% Ni+% Co) of about 0.5 to about 2. Thus, it is possible to recover Cu, Ni and Co as well as several other metals, including In, Ge, Pb, Bi, precious metals and platinum group metals.

Abstract: A method for the reduction of corrosion in a treatment unit acid used for separating hydrogen sulfide from and acid gas stream using an alkaline absorption solution. Ions comprising the S2? and/or HS? ions formed by the absorption of the hydrogen sulfide in the absorbent solution are subjected to in situ electrochemical oxidization to form polysulfide ions which form a protective coating on the surfaces of the unit.

Abstract: Methods and systems are provided for the in situ generation of polysulfide ions in a process stream including S2? and/or HS? ions. Methods and systems are also provided to ameliorate corrosion in a process stream containing an acid gas or a scrubbing agent solvent, and abate mercury and cyanide in process streams containing a scrubbing agent solvent.

Abstract: Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets.

Abstract: Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets.

Abstract: Polysulphide produced by oxidizing white liquor includes both active and inactive components. “Active” polysulphide is the only component that increases pulp yield. The amount of active polysulphide formed when manganese oxides are used as catalysts in the generating process is increased by adding a co-catalyst. Adding bismuth compounds and, in particular, bismuth oxide as a co-catalyst increases the total amount of polysulphide formed with all the manganese oxides and increases the amount of active polysulphide produced particularly when using the lower manganese oxides. The co-catalyst also increases the number of cycles in which the most active catalyst, manganese dioxide, can participate before losing efficiency. Other elements in the same group and adjacent groups in the periodic table are active but these other elements are more soluble than bismuth and are toxic.

Abstract: Systems are disclosed for making and using micro-porous particulates at least partially composed of metal sulfides, particularly alkaline earth metal and transition metal sulfides, as sorbents for removal of mercury from flue gas. Calcium sulfide micro-porous powders derived from the high temperature reduction of calcium sulfate and calcium sulfite are disclosed to be reactive substrates for a group of sorbents for adsorption of mercury from coal combustion flue gases produced by the utilities industry, as well as from natural gas and gaseous and liquid hydrocarbons. The sorbents are useful for cost-effectively adsorbing elemental mercury and oxidized mercury species such as mercuric chloride from flue gases, including those containing acid gases (e.g., SO.sub.2, NO and NO.sub.2, and HCl), over a wide range of temperatures.

Abstract: A calcium-sodium polysulfide chemical reagent and methods for producing the reagent. The reagent is a blend of calcium polysulfide and sodium polysulfide that can be prepared using various types, sources and ratios of lime, elemental sulfur and sulfide ion using either virgin or waste materials. The reagent is amenable to inexpensive and high rate production methods at ambient or warmer temperatures. The reagent can be used to precipitate metals from wastewater, stabilize hexavalent chrome in hazardous waste residues, remove mercury from coal fired power plants, and as an electrolyte in large-scale bromide/polysulfide electrical storage batteries.

Abstract: A sulfur species-containing feed gas is processed in a treatment plant in which COS is hydrolyzed, and in which so produced hydrogen sulfide and other sulfur species are absorbed in a lean hydrocarbon liquid. The sulfur species in the so formed rich hydrocarbon liquid are then subjected to catalytic conversion into disulfides, which are subsequently removed from the rich solvent. Most preferably, sulfur free lean solvent is regenerated in a distillation column and/or refinery unit, and light components are recycled from the rich hydrocarbon liquid to the absorber.

Abstract: A composition including an aqueous solution of calcium polysulfide and an amount of a precipitation preventing compound effective to reduce or eliminate precipitation of the calcium polysulfide at low concentrations. The precipitation preventing compound is selected from the group consisting of sodium hydrosulfide, potassium hydrosulfide, sodium sulfide, and potassium sulfide. A method of reducing or preventing precipitation of calcium polysulfide added to the water in an irrigation system by first injecting the precipitation preventing compound into the water in an amount effective to reduce or eliminate precipitation of the calcium polysulfide at low concentrations. Sodium methyldithiocarbamate can be added to the calcium polysulfide/precipitation preventing compound solution without any substantial precipitation.

Abstract: The present invention relates to a process for the recovery of elemental sulphur from residues produced in hydrometallurgical processes based on leaching with a solution of sodium sulphide in which the sulphur contained in the residues is selectively leached as sodium polysulphide. The sulphur leaching solution is conveniently regenerated and recycled to the process.

Abstract: A calcium-sodium polysulfide chemical reagent and methods for producing the reagent. The reagent is a blend of calcium polysulfide and sodium polysulfide that can be prepared using various types, sources and ratios of lime, elemental sulfur and sulfide ion using either virgin or waste materials. The reagent is amenable to inexpensive and high rate production methods at ambient or warmer temperatures.

Abstract: Polysulphide produced by oxidizing white liquor includes both active and inactive components. “Active” polysulphide is the only component that increases pulp yield. The amount of active polysulphide formed when manganese oxides are used as catalysts in the generating process is increased by adding a co-catalyst. Adding bismuth compounds and, in particular, bismuth oxide as a co-catalyst increases the total amount of polysulphide formed with all the manganese oxides and increases the amount of active polysulphide produced particularly when using the lower manganese oxides. The co-catalyst also increases the number of cycles in which the most active catalyst, manganese dioxide, can participate before losing efficiency. Other elements in the same group and adjacent groups in the periodic table are active but these other elements are more soluble than bismuth and are toxic.

Abstract: A calcium-sodium polysulfide chemical reagent and methods for producing the reagent. The reagent is a blend of calcium polysulfide and sodium polysulfide that can be prepared using various types, sources and ratios of lime, elemental sulfur and sulfide ion using either virgin or waste materials. The reagent is amenable to inexpensive and high rate production methods at ambient or warmer temperatures. The reagent can be used to precipitate metals from wastewater, stabilize hexavalent chrome in hazardous waste residues, remove mercury from coal fired power plants, and as an electrolyte in large-scale bromide/polysulfide electrical storage batteries.

Abstract: A metal chalcogenide composite nano-particle comprising a metal capable of forming p-type semiconducting chalcogenide nano-particles and a metal capable of forming n-type semiconducting chalcogenide nano-particles, wherein at least one of the metal chalcogenides has a band-gap between 1.0 and 2.9 eV and the concentration of the metal capable of forming p-type semiconducting chalcogenide nano-particles is at least 5 atomic percent of the metal and is less than 50 atomic percent of the metal; a dispersion thereof; a layer comprising the nano-particles; and a photovoltaic device comprising the layer.

Abstract: Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets.

Abstract: Oxidized white liquor is heat treated to increase the concentration of polysulphide measured at 285 or 286 nm (PSUV) or measured at 416 nm (PSVIS) and the PSUV/PSGR or PSVIS/PSGR ratio, whereby the content of active polysulphide in the total polysulphide is increased which active polysulphide can be exploited to increase pulp yield in Kraft pulping.

Abstract: An efficient process to produce calcium thiosulfate (CaS2O3) from lime, sulfur and oxygen is described. By selecting appropriate process conditions such as mole ratios of lime to sulfur, temperature and pressure of the reaction process and the oxidation conditions, including rate and duration, the concentration of byproducts in the resulting suspension can be reduced to about 2% by weight or less. The solid particulate dispersion in the suspension tends to form a slimy solid suspension that is hard to filter if not treated properly. The suspension then can be acidified and treated with a flocculent. This agglomerates the solids into a floc that filters with ease. The resulting calcium thiosulfate is a clear liquid with concentrations achievable up to 29%.

Abstract: Methods of converting a sulfide in a composition to polysulfide are described, one method comprising the steps of exposing the composition to conditions and for a time sufficient to cause conversion of at least a portion of the sulfide, to polysulfide to form a modified composition; and controlling the conversion to polysulfide by measuring a color parameter of the modified composition.

Abstract: The present invention provides a process for preparing polysulfide. More particularly, the process of the present invention allows one to prepare the amount of polysulfide needed using clarified white liquor, and to be used when and where it is needed during the cooking process. The process comprises reacting alkaline digesting liquor after clarification with a catalytic amount of a transition metal oxide catalyst, most preferably manganese dioxide. The reaction is conducted at a temperature of 98° C. or less, and is conducted for a short period of time, e.g., less than five minutes, with no oxygen gas or air being introduced with the catalyst and the main flow of clarified liquor.

Abstract: The present invention relates to a method for labelling a sulfide compound with technetium or rhenium, comprising the reaction of a disulfide compound with pertechnetate or perrhenate in the presence of borohydride exchange resin to obtain a complex of technetium or rhenium with the sulfide compound. The method can directly label disulfide compounds with technetium or rhenium, can skip the synthetic step of thiol-protected S-precursor, and is useful for high value-added radiopharmaceuticals.

Abstract: Methods of converting a sulfide in a composition to polysulfide are described, one method comprising the steps of exposing the composition to conditions and for a time sufficient to cause conversion of at least a portion of the sulfide, to polysulfide to form a modified composition; and controlling the conversion to polysulfide by measuring a color parameter of the modified composition.

Abstract: Hydroxalkylaminium polysulfides are used to provide cold stability to ammonium polysulfide solutions. Hydroxyalkylaminium sulfides or polysulfides also are used to solubilize unwanted sulfur. Preferred aminium ions are monohydroxyalkylaminium ions, preferably monoethanolaminium ions. When added to an aqueous stream comprising free cyanide ions (including HCN), the polysulfide solution reduces corrosion of metal equipment contacted by the stream by converting the free cyanide ions into thiocyanate ions.

Abstract: A process is provided for the removal of hydrogen sulfide out of a gaseous stream (22), such as a natural gas, by contacting the hydrogen sulfide containing gas with a sorbing liquid (26) containing a tertiary amine so that the hydrogen sulfide is sorbed into the liquid in absorber (11) and transferring the sorbing liquid/hydrogen sulfide mixture to a reactor (15) where the tertiary amine promotes the conversion of the hydrogen sulfide into polysulfide via reaction with sulfur; transferring the polysulfide solution from the reactor (15) to a regenerator (10) where polysulfide is converted into elemental sulfur via reaction with air (9); transferring at least a portion of the solution (25) containing elemental sulfur, as well as sulfate and thiosulfate species, into a mixture (36) where it is contacted with gaseous ammonia which reacts with the sulfate and thiosulfate species to produce ammonium sulfate and ammonium thiosulfate which are removed from the solution while the remaining portion of solution (25) is

Abstract: The present invention deals with the implementation of advanced controllers that are capable of achieving the desired controlling performance in a polysulfide reactor. These controllers are robust enough to counteract process disturbances as they learn continuously from the measurements of the inputs and outputs. The process comprises controlling the residence time, reaction temperature and oxygen partial pressure using an advanced controller, which adjusts the necessary parameters in order to counteract process disturbances.

Abstract: The present invention provides a process for preparing polysulfide. More particularly, the process of the present invention allows one to prepare the amount of polysulfide needed using clarified white liquor, and to be used when and where it is needed during the cooking process. The process comprises reacting alkaline digesting liquor after clarification with a catalytic amount of a transition metal oxide catalyst, most preferably manganese dioxide. The reaction is conducted at a temperature of 98° C. or less, and is conducted for a short period of time, e.g., less than five minutes, with no oxygen gas or air being introduced with the catalyst and the main flow of clarified liquor.

Abstract: The present invention is a new and simple method of decomposing ammonium tetrathiomolybdate (ATTM) in an organic solvent with added water under H2 pressure. Model compound reactions of 4-(1-naphthylmethyl)bibenzyl (NMBB) were carried out at 350-425° C. under H2 pressure in order to examine the activity of the Mo sulfide catalysts generated from ATTM with and without added water for C—C bond cleavage and hydrogenation of aromatic ring. The Mo sulfide catalysts generated from ATTM with added water were much more effective for C—C bond cleavage and hydrogenation of aromatic moieties at 350-425° C. than those from ATTM alone. Two-step tests revealed that the addition of water is effective for generating highly active Mo sulfide catalyst from ATTM, but water itself does not promote catalytic conversion. Removal of water after the decomposition of ATTM with added water at 350-400° C. under H2 pressure by hot purging gives highly active Mo sulfide catalyst.

Abstract: Provided is a process for the preparation of polysulfides which comprises reaching sodium sulfide with oxygen in the presence of a transition metal oxide, preferably MnO2, and with the consumption rate of O2 being at least 1.5×10−4 moles/l/sec. The process of the present invention is preferably conducted in a self-recirculated reactor, which has been found to allow easy control of the O2 consumption rate.

Abstract: It is an object of the present invention to produce a cooking liquor containing polysulfide sulfur at a high concentration from white liquor in a pulp production process with a high selectivity at a low electric power with very little production of thiosulfate ions as by-product. The present invention provides a method for producing polysulfides, which comprises introducing a solution containing sulfide ions into an anode compartment of an electrolytic cell comprising the anode compartment provided with a porous anode, a cathode compartment provided with a cathode and a diaphragm partitioning the anode compartment and the cathode compartment, for electrolytic oxidation to obtain polysulfide ions, wherein at least the surface of said anode is made of nickel, and the porous anode has a physically continuous three-dimensional network structure.

Abstract: The present invention is a new and simple method of decomposing ammonium tetrathiomolybdate (ATTM) in an organic solvent with added water under H.sub.2 pressure. Model compound reactions of 4-(1-naphthylmethyl)bibenzyl (NMBB) were carried out at 350-425.degree. C. under H.sub.2 pressure in order to examine the activity of the Mo sulfide catalysts generated from ATTM with and without added water for C--C bond cleavage and hydrogenation of aromatic ring. The Mo sulfide catalysts generated from ATTM with added water were much more effective for C--C bond cleavage and hydrogenation of aromatic moieties at 350-425.degree. C. than those from ATTM alone. Two-step tests revealed that the addition of water is effective for generating highly active Mo sulfide catalyst from ATTM, but water itself does not promote catalytic conversion. Removal of water after the decomposition of ATTM with added water at 350-400.degree. C. under H.sub.2 pressure by hot purging gives highly active Mo sulfide catalyst.

Abstract: The invention relates to a process for producing polysulphide by means of oxidizing sulphide in spent liquors from kraft cellulose cooking. The process is characterized in that green liquor is firstly enriched in sulphide and then oxidized.

Abstract: A method for producing polysulfides, which comprises introducing a solution containing sulfide ions into an anode compartment of an electrolytic cell comprising the anode compartment provided with a porous anode, of which at least the surface is made of carbon, a cathode compartment provided with a cathode, and a diaphragm partitioning the anode compartment and the cathode compartment, and carrying out electrolytic oxidation to obtain polysulfide ions.

Abstract: A method for producing an electrochemically advantageous lithium ion-conductive solid electrolyte with high ionic conductivity, low electronic conduction and electrochemical stability is disclosed. The method comprises the steps of synthesizing lithium sulfide by reacting lithium hydroxide with a gaseous sulfur source at a temperature of not less than 130.degree. C. and not more than 445.degree. C., thermally melting plural compounds containing at least silicon sulfide and the synthesized lithium sulfide, and cooling the molten mixture. The silicon sulfide is synthesized by the steps of adding a silicon powder to molten sulfur while stirring to disperse the silicon powder in the molten sulfur and heating the silicon powder-dispersed sulfur in a reaction chamber under reduced pressure.

Abstract: A composition for treating water or flue gases that contains metal ions and possibly also organic and/or inorganic compounds is produced by reacting sulfur with an alkali- and/or alkaline earth metal hydroxide in the presence of water.The inventive composition corresponds to general formula IM.sub.x S.sub.y O.sub.z, (I)where M represents an alkali or alkaline earth metal,x is 1 or 2,y is in the range 0.5x-4.0x, andz is in the range 0.1-2.5.Alkali sulfite salts, particularly sodium salts, may also be added to the compound for reducing H.sub.2 S emission.

Abstract: A process and system for removing hydrogen sulfide from a gaseous stream such as one of natural gas. A sour gas stream containing H.sub.2 S is contacted with a nonaqueous, water-insoluble sorbing liquor which comprises an organic solvent for elemental sulfur, dissolved elemental sulfur, an organic base to promote the reactions, and an organic solubilizing agent an agent suitable for maintaining the solubility of polysulfide intermediates which may otherwise separate when they are formed during operation of the process. Hydrogen sulfide (H.sub.2 S) gas is sorbed into this liquor and then reacts with the dissolved sulfur in the presence of the base to form polysulfide molecules. The solution is then sent to a reactor where sufficient residence time is provided to allow the polysulfide forming reactions to reach the desired degree of completion. From the reactor, the solution flows to a regenerator where the solution is oxidized (e.g., by contact with air), forming dissolved elemental sulfur and water.

Abstract: The invention provides methods for purifying hydrogen sulfide gas having impurities therein. In one exemplary method, the hydrogen sulfide gas is purified by passing the gas through a filter media, with at least some of the impurities being trapped within the filter media. A catalyst may also be provided to break down some of the impurities to hydrogen sulfide and sulfur, so that the sulfur may be trapped and collected within the filter media.

Abstract: The present invention provides a method for separately removing mercaptans and hydrogen sulfide from a hydrocarbon gas stream by passing the gas through a bed which includes iron oxide which catalyzes the formation of disulfides and trisulfides from mercaptans and also reacts with at least part of the hydrogen sulfide to form acid-stable solids; causing the di- and trisulfides to exit the bed in the gas phase; and removing and recovering the di- and trisulfides by adsorption or condensation. Any remaining hydrogen sulfide may be scavenged from the gas stream by passage through a bed containing iron oxide similar to that used first above. If the gas stream contains substantial amounts of hydrocarbon aerosols, they should be filtered out in advance of the bed.

Abstract: Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

Abstract: A composition for treating water that contains metal ions and possibly also organic and/or inorganic compounds is produced by reacting sulfur with an alkali- and/or alkaline earth metal hydroxide in the presence of water.The inventive composition corresponds to general formula IM.sub.x S.sub.y O.sub.z, (I)whereM represents an alkali or alkaline earth metal,x is 1 or 2,y is in the range 1.5x-2.5x, andz is in the range 0.1-2.5.

Abstract: A stabilized ammonium polysulfide solution comprising an aqueous solution of ammonium polysulfide and a stabilizing amount of a water soluble, stabilizing compound that can be an azacyclic compound, a compound having the formula R--O--(C.sub.n H.sub.2n)NH.sub.2 or a compound having the formula (CH.sub.3).sub.2 NR.sub.1, the pH of the composition being from 7 to 14, the stabilized composition being useful in controlling the cyanide concentration in aqueous streams.

Abstract: Binary rare earth/sulfur or transition metal/sulfur compounds, e.g., the higher sulfides or sesquisulfides of the rare earths, are prepared by confinedly reacting either a rare earth compound, e.g., an oxide, carbonate or hydroxide, or a transition metal oxide, with a carbon compound of sulfur in gaseous state, e.g., CS.sub.2, within a sealed enclosure.

Abstract: A process for removing sulfur from an organic polysulfide by reaction with an aqueous stripping solution of at least one sulfide salt and/or hydrosulfide salt in a multi-stage, continuous, countercurrent flow, reaction system wherein the sulfur is stripped from the polysulfide into the aqueous stripping solution phase which is separated from the polysulfide organic phase.

Abstract: Catalyst for hydrorefining hydrocarbon feedstocks consisting of niobium trisulphide, bulk or deposited on an inert support.This catalyst is particularly efficient for the reactions of scission of carbon-nitrogen and carbon-sulphur bonds.

Abstract: Methods for the preparation of lower sodium polysulfides such as sodium disulfide from higher sodium polysulfides and sodium. To this end, either molten sodium polysulfide placed in a receiver is reacted with sodium in a stoichiometric ratio corresponding to the desired product under vigorous agitation and under protective gas or the higher polysulfide and the sodium are dosed into a polysulfide melt in a receiver under the same conditions either alternatively or simultaneously. In all instances, the dosing of the sodium is set so that the reaction mixture remains capable of being agitated and the agitation is continued until the desired product composition has been achieved.

Abstract: A method of preparing sodium monosulfide by means of reacting a sodium polysulfide with sodium under protective gas, the sodium polysulfide is placed in a first stage in a finely distributed, solid state in a receiver, preheated to temperatures of 100.degree.-150.degree. C., liquid sodium is gradually added in the required amount to the material in the receiver under intensive mixing, whereby the temperature of the reaction mixture is maintained at 120.degree.-250.degree. C. and in a second stage the formed initial product is allowed to continue to react, or postreact under continuation of the mixing at 250.degree.-480.degree. C., until a Na.sub.2 S content of at least 95% by weight has been attained.

Abstract: A method for removing sulfur dioxide from flue gases in a wet scrubbing system where calcium thiosulfate and calcium polysulfides are formed by the reaction of lime and emulsified sulfur and the mixture added to a recycle tank of the wet scrubber where it reacts with sulfites and bisulfites in the scrubbing slurry to produce thiosulfates from the calcium polysulfides, with the slurry then returned to the scrubber. The mixture of calcium thiosulfate and calcium polysulfides may be formed in the lime slaking tank or lime storage tank of a lime scrubbing system or formed in a mixing tank and added to a lime or limestone scrubbing system.

Abstract: A method of treating an aqueous sodium sulfide solution, such as white liquor in kraft pulping systems, for the oxidation of the sulfide with oxygen in the presence of a specific activated carbon catalyst which is (a) a particulate activated carbon catalyst having an average particle diameter of 0.2-4 mm, a pore volume of at least 0.25 cc/g in pores with diameters of not smaller than 100 .ANG. and a pore volume of at least 35% of the total pore volume in pores with diameters of not smaller than 100 .ANG. or (b) a fibrous activated carbon catalyst having a specific surface area of 300-2500 m.sup.2 /g and an outer surface area of 0.1-5 m.sup.2 /g.

Abstract: Method of preparing SbSbS.sub.4 product having a low level of free sulfur impurity, which includes mixing aqueous solutions of an alkali metal thioantimonate and a halide stabilized antimony trihalide to form a reaction mixture, while maintaining the reaction mixture at a pH of less than 7, to provide the SbSbS.sub.4 product having a low level of free sulfur impurity.