Abstract: Disclosed is a novel method for the selective molecular conversion of raw material carbon nanotubes containing a mixture of metallic carbon nanotubes and semiconductive carbon nanotubes in a manner that is based on the electrical properties or diameter of the carbon nanotubes. The present invention causes a photoreaction of raw material carbon nanotubes containing a mixture of metallic carbon nanotubes and semiconductive carbon nanotubes with a disulfide or a sulfide of the following formula (I) or (II) (wherein R1 and R2 each independently represent a hydrocarbon group that may have a substituent) in an organic solvent that contains the raw material carbon nanotubes and the disulfide of the formula (I) or the sulfide of the formula (II), so as to selectively functionalize the metallic carbon nanotubes, or functionalize the carbon nanotubes diameter selectively.

Abstract: The present invention relates to a method for producing lithium carbonate, which is important as a raw material of a lithium ion battery and the like, from brine resources. More specifically, the invention relates to a method for producing lithium carbonate, in which carbon dioxide gas obtained by calcining limestone is introduced, in the presence of ammonia, into a concentrated brine, which is prepared from a lithium-containing brine as a raw material through an evaporative concentrating step, a desulfurizing step and an electrodialysis step, thereby depositing lithium carbonate crystals, and the crystals thus deposited are recovered through solid-liquid separation.

Abstract: In some embodiments, the invention provides systems and methods for removing carbon dioxide and/or additional components of waste gas streams, comprising contacting the waste gas stream with an aqueous solution, removing carbon dioxide and/or additional components from the waste gas stream, and containing the carbon dioxide and/or additional components, in one form or another, in a composition. In some embodiments, the composition is a precipitation material comprising carbonates, bicarbonates, or carbonates and bicarbonates. In some embodiments, the composition further comprises carbonate and/or bicarbonate co-products resulting from co-processing SOx, NOx, particulate matter, and/or certain metals. Additional waste streams such as liquid, solid, or multiphasic waste streams may be processed as well.

Abstract: A gasifier 10 includes a first chemical process loop 12 having an exothermic oxidizer reactor 14 and an endothermic reducer reactor 16. CaS is oxidized in air in the oxidizer reactor 14 to form hot CaSO4 which is discharged to the reducer reactor 16. Hot CaSO4 and carbonaceous fuel received in the reducer reactor 16 undergo an endothermic reaction utilizing the heat content of the CaSO4, the carbonaceous fuel stripping the oxygen from the CaSO4 to form CaS and a CO rich syngas. The CaS is discharged to the oxidizer reactor 14 and the syngas is discharged to a second chemical process loop 52. The second chemical process loop 52 has a water-gas shift reactor 54 and a calciner 42. The CO of the syngas reacts with gaseous H2O in the shift reactor 54 to produce H2 and CO2. The CO2 is captured by CaO to form hot CaCO3 in an exothermic reaction.

Abstract: In a retrofit system for hot solids combustion and gasification, a chemical looping system includes an endothermic reducer reactor 12 having at least one materials inlet 22 for introducing carbonaceous fuel and CaCO3 therein and a CaS/gas outlet 26. A first CaS inlet 40 and a first CaSO4 inlet 64 are also defined by the reducer reactor 12. An oxidizer reactor 14 is provided and includes an air inlet 68, a CaSO4/gas outlet 46, a second CaS inlet 44, and a second CaSO4 inlet 66. A first separator 30 is in fluid communication with the CaS/gas outlet 26 and includes a product gas and a CaS/gas outlet 32 and 34 from which CaS is introduced into said first and second CaS inlets. A second separator 50 is in fluid communication with the CaSO4/gas outlet 46 and has an outlet 52 for discharging gas therefrom, and a CaSO4 outlet from which CaSO4 is introduced into the first and second CaSO4 inlets 62, 66.

Abstract: A gasifier 10 includes a first chemical process loop 12 having an exothermic oxidizer reactor 14 and an endothermic reducer reactor 16. CaS is oxidized in air in the oxidizer reactor 14 to form hot CaSO4 which is discharged to the reducer reactor 16. Hot CaSO4 and carbonaceous fuel received in the reducer reactor 16 undergo an endothermic reaction utilizing the heat content of the CaSO4, the carbonaceous fuel stripping the oxygen from the CaSO4 to form CaS and a CO rich syngas. The CaS is discharged to the oxidizer reactor 14 and the syngas is discharged to a second chemical process loop 52. The second chemical process loop 52 has a water-gas shift reactor 54 and a calciner 42. The CO of the syngas reacts with gaseous H2O in the shift reactor 54 to produce H2 and CO2. The CO2 is captured by CaO to form hot CaCO3 in an exothermic reaction.

Abstract: A method of treating aqueous salt solutions to provide a solution suitable for vitrification to a stable glass matrix for long term storage is described. In particular, salt solutions composed of aqueous nuclear waste materials are suitable for treatment by the described method. Specifically, salt solutions which have a sulfate to sodium mole ratio that does not permit easy vitrification into stable glasses may be treated by the present invention. The present method decreases the volume of vitrified glass.

Abstract: Methodology for formulating sodium bicarbonate and potassium sulfate. In one embodiment, sodium sulfate and ammonium bicarbonate are reacted to form sodium bicarbonate with the remaining liquor or brine treated with sulfuric acid to remove carbonates with subsequent precipitation of potassium sulfate. A further embodiment employs ammonium bicarbonate, ammonia gas or carbon dioxide to precipitate sodium bicarbonate. The result of the methods is the production of high quality fertilizer and food grade sodium bicarbonate.

Abstract: A process is provided for recovering sodium bicarbonate and ammonium sulfate from a solution containing sodium sulfate derived from a process for removing sulfur contaminants out of a gas with sodium bicarbonate reagent. Sodium bicarbonate is precipitated and removed from the solution. Sodium sulfate or ammonium bicarbonate is added to the solution to form a second precipitate of sodium bicarbonate, which is removed from the solution. The solution is conditioned by either heating the solution to 95.degree. C. to liberate ammonia and carbon dioxide or by adding sulfuric acid to the solution to decompose any carbonates. The solution is cooled to a temperature between -2 to 2.degree. C. to form a third precipitate of sodium bicarbonate. Sulfuric acid is added to the solution to decompose any carbonate minerals, and purified ammonium sulfate solution is recovered.

Abstract: The concentration of carbon monoxide in a gaseous medium is reduced by selective catalytic oxidation in the presence of gaseous oxygen by passing the gaseous medium through a catalyst capable of oxidizing carbon monoxide in an exothermic reaction at temperatures within a given temperature range and by controlling the temperatures encountered in the catalyst in such a manner that the exothermic reaction takes place first above a threshold temperature below which the catalyst would be rapidly inactivated at the relatively high carbon monoxide concentrations present in the gaseous medium as it enters the catalyst, and subsequently, after the carbon monoxide concentration has been reduced to an acceptable level, at less than the threshold temperature to further reduce the carbon monoxide concentration to a desired minimum level below that achievable at temperatures above the threshold temperature.

Abstract: A method for the recovery of chemical values from spent lignocellulosic pulping liquor salts to produce white liquor of different sulfidities. Preferably, the white liquor is in the form of separate liquid streams, each of which is of a sulfidity that is different from the sulfidity of others of the streams. The method also provides for developing a white liquor stream which is essentially free of sulfide values, but which contains sodium hydroxide. Further, the method provides for recovery of titanium values for recycling.

Abstract: This invention is a regenerable process for producing gaseous hydrogen sulfide in concentrated form from sulfur dioxide obtained from a dilute gas source by (1) reacting the SO.sub.2 with a concentrated solution of Na.sub.2 SO.sub.3 to form Na.sub.2 S.sub.2 O.sub.5 in solution and then either: (2) reacting the Na.sub.2 S.sub.2 O.sub.5 with Na.sub.2 CO.sub.3 to form solid Na.sub.2 SO.sub.3, a concentrated solution of Na.sub.2 SO.sub.3 which is recycled to the SO.sub.2 reaction and concentrated gaseous CO.sub.3 which is used in a subsequent step, (3) reducing the Na.sub.2 SO.sub.3 to Na.sub.2 S, (4) reacting the Na.sub.2 S with solid NaHCO.sub.3 to form gaseous H.sub.2 S and Na.sub.2 CO.sub.3, (5) recycling part of the Na.sub.2 CO.sub.3 to (2) above and reacting the remainder with concentrated CO.sub.2 from (2) above to form solid NaHCO.sub.3 and recycling the solid NaHCO.sub.3 to (4) above, or; (2) reacting the Na.sub.2 S.sub.2 O.sub.5 with NaHCO.sub.3 to form solid Na.sub.2 SO.sub.

Abstract: An improved system for recovering CO.sub.2 from flue gases containing SO.sub.2 at low CO.sub.2 partial pressure. The system includes the use of K.sub.2 CO.sub.3 as the solvent, regeneration of the solvent, and removal of SO.sub.2 and SO.sub.4.

Abstract: A process for removing sulfur oxides from waste gas is provided. The gas is contacted with an activated sodium carbonate sorbent and, utilizing an alkaline ammonia liquor so as to reduce the flow rates and loss of alkalinity, the spent sorbent is regenerated with an alkaline earth metal oxide or hydroxide.

Abstract: A process for removing sulfur oxides from waste gas is provided. The gas is contacted with a sorbent selected from sodium bicarbonate, trona and activated sodium carbonate and, utilizing an alkaline liquor containing borate ion so as to reduce flow rates and loss of alkalinity, the spent sorbent is regenerated with an alkaline earth metal oxide or hydroxide.

Abstract: A process for converting potassium sulfate to potassium carbonate in which a mixture of potassium sulfate and calcium oxide are reacted at a temperature in the range of between about 700.degree. C. and about 800.degree. C. with a gaseous mixture having a minor amount of hydrogen and/or carbon monoxide in a diluent with the calcium oxide being present in an amount not greater than about 20 percent by weight of the potassium sulfate to produce an aqueous mixture of potassium sulfide, potassium bisulfide, potassium hydroxide and calcium sulfide and a gaseous mixture of steam and hydrogen sulfide. The potassium and calcium salts are quenched to produce an aqueous slurry of soluble potassium salts and insoluble calcium salts and a gaseous mixture of steam and hydrogen sulfide. The insoluble calcium salts are then separated from the aqueous solution of soluble potassium salts.

Abstract: In the Stretford process wherein hydrogen sulfide, obtained for example, in the catalytic conversion of sulfur compounds, is absorbed into an alkaline solution of the sodium salt of anthraquinone disulfonic acid (ADA) and sodium vanadate and eventually converted to elemental sulfur by a reaction of the sodium vanadate with the hydrogen sulfide, some of the hydrogen sulfide undergoes side reactions and is converted to undesirable by-products, e.g., sodium sulfate and sodium thiosulfate. These by-products were removed in the prior art by burning; however, the expensive salts of ADA were also burned in the process of the prior art. In the present improvement, the sodium salts of ADA are preferentially removed in an adsorption column filled with a macroporous adsorption resin, prior to the combustion stage. The adsorption column can be regenerated either with water or with an aqueous solution of sodium carbonate formed in the combustion stage.

Abstract: In a magnetohydrodynamic power plant where calcium carbonate seed is used to increase conductivity and scavenge sulfur, forming potassium sulfate, an improved process is disclosed for converting the potassium sulfate back into potassium carbonate for reuse in the power plant. The potassium sulfate is first reacted with a reducing agent in the presence of up to about 40% boric oxide at about 800.degree. to about 1300.degree. C. for at least about one hour to produce potassium sulfide. The potassium sulfide is then reacted with carbon dioxide and steam at about 450.degree. to about 750.degree. C. for at least about an hour to produce hydrogen sulfide and potassium carbonate. Finally, the potassium carbonate and the hydrogen sulfide are separated and the potassium carbonate is recycled.

Abstract: A process for reacting potassium carbonate with the sulfur in an MHD gas to form potassium sulfate and for recovering the potassium carbonate for recycle as a seeding material for the MHD gas.

Abstract: Waxy hydrocarbon oils, e.g., of petroleum origin, boiling within the approximate range of 450.degree. to 1050.degree. F. are catalytically dewaxed utilizing a catalyst comprising a crystalline aluminosilicate zeolite possessing particularly characterized pore openings, such as, for example, ZSM-23 or ZSM-35, which may be associated with a hydrogenation metal.

Abstract: A method of treating an aqueous alkali metal sulfide-containing liquor to remove the sulfur values therefrom. Broadly, the method comprises introducing an alkaline liquor containing an alkali metal sulfide into a neutralization zone where it is intimately contacted and reacted with a sufficient amount of a gas containing a major amount of H.sub.2 S and a minor amount of CO.sub.2 to produce a product liquor of reduced alkalinity consisting essentially of a slurry of alkali metal bicarbonate and alkali metal bisulfide. The product liquor is withdrawn from the neutralization zone and introduced into a carbonation zone where it is contacted with a sufficient amount of a CO.sub.2 -containing gas to produce a product stream comprising a slurry of alkali metal bicarbonate crystals substantially free of alkali metal bisulfide and an H.sub.2 S-rich product gas containing a minor amount of CO.sub.2. The H.sub.

Abstract: Sodium thiosulfate is purged from a sulfur dioxide removal system involving contact of a sulfur dioxide-containing gas with a solution containing sodium sulfite to absorb sulfur dioxide from the gas. A portion of the liquid from a desorption zone containing a minor amount of sodium thiosulfate and a relatively large amount of sodium bisulfite, is treated to reduce the amount of water in the medium so that solids are precipitated from the liquid phase. The insolubles containing sodium sulfites are removed from the liquid. The liquid separated from the solids can be discarded and thereby purge thiosulfate more selectively with respect to other sodium salts. Also, the sodium values of the sodium thiosulfate-containing purge liquid can be recovered in active form by chemical reduction, and, preferably, carbonation. A sodium sulfate purge material from the absorption-desorption system can also be subjected to the chemical reduction system for further recovery of active sodium values.

Abstract: Substantially spherical alumina particles are obtained by a process comprising ageing substantially spherical alumina hydrogel particles obtained by the oil-drop method in an ammonium hydroxide solution wherein the concentration of ammonia changes continuously from an initial concentration in the range of from about 0.05 wt.% to about 0.5 wt.% to a final concentration in the range of from about 0.8 wt.% to about 2.5 wt.%. Alumina particles obtained by this process possess improved physical strength. Alumina particles which are obtained by calcining alumina particles aged in an ammonium hydroxide solution, wherein the concentration of ammonia increases continuously, at a temperature in the range of from 650.degree. to 800.degree. C in an atmosphere containing 30 mol.% or more of H.sub.2 O possesses a further improved thermal stability.

Abstract: Catalytic conversion of hydrocarbon compounds in the presence of crystalline zeolite ZSM-38, or a thermal decomposition product thereof, is provided. Zeolite ZSM-38 has a composition, in the anhydrous state, expressed in terms of mole ratios of oxides as follows:(0.3-2.5)R.sub.2 O:(0-0.8)M.sub.2 O:Al.sub.2 O.sub.3 :(x)SiO.sub.2wherein R is an organic cation, especially an organic nitrogen-containing cation, M is an alkali metal cation and x is greater than 8, and is characterized by a specified X-ray powder diffraction pattern.

Abstract: Catalytic conversion of organic compounds in the presence of crystalline zeolite ZSM-23, or a thermal decomposition product thereof, is provided. Zeolite ZSM-23 has a composition, in the anhydrous state, expressed in terms of mole ratios ofoxides, as follows:(0.58 to 3.4)M.sub.2/n O : Al.sub.2 O.sub.3 : (40 to 25)SiO.sub.2wherein M is at least one cation having a valence n, and is characterized by a specified X-ray powder diffraction pattern.

Abstract: A method of removing and preferably recovering sulfur values from an alkali metal sulfide and carbonate mixture comprising the steps of (1) introducing the mixture in an aqueous medium into a first carbonation zone and reacting the mixture with a gas containing a major amount of CO.sub.2 and a minor amount of H.sub.2 S; (2) introducing the resultant product from step 1 into a stripping zone maintained at subatmospheric pressure, and contacting this product with steam to produce a gaseous mixture, comprising H.sub.2 S and water vapor, and a liquor of reduced sulfide content; (3) introducing the liquor of reduced sulfide content into a second carbonation zone, and reacting the liquor with substantially pure gaseous CO.sub.2 in an amount sufficient to precipitate bicarbonate crystals and produce an offgas containing CO.sub.2 and H.sub.

Abstract: There is disclosed a process for reducing the loss of sodium values in a system for removing sulfur dioxide from a gas by the use of an absorption-desorption cycle employing aqueous sodium sulfite as the essential absorption solution. Sodium sulfate and/or sodium thiosulfate build-up in the system is avoided and the loss of sodium values reduced by subjecting sodium sulfate and/or sodium thiosulfate-containing material to chemical reduction to form a product containing a substantial amount of sodium carbonate. Preferably, the reduced product is subjected to carbonation followed by reaction of the bicarbonate and bisulfide components of the mixture to give a resulting liquid which is more suitable for use in the absorption-desorption process. By-product gases can be incinerated to produce sulfur dioxide-containing gases which can be charged to the sulfur dioxide absorption zone.

Abstract: Sodium, potassium and ammonium thiosulfates may be converted to a mixture of the corresponding carbonates and sulfides by first partially reducing the thiosulfate with CO to formate in a first reduction zone, and then using the formate so produced to effect further reduction of the thiosulfate in a second reduction zone.

Abstract: The invention relates to a process for separating hydrogen sulphide from clarified green liquor, including precarbonating green liquor with a carbon dioxide rich gas, adding alkali bicarbonate to the precarbonated green liquor and stripping hydrogen sulphide therefrom forming simultaneously alkali carbonate, and preparing the alkali bicarbonate used in the process from the alkali carbonate formed. The process of the invention is carried out by performing the hydrogen sulphide stripping without crystallizing the alkali carbonate formed, preparing the alkali bicarbonate partly from alkali carbonate-alkali sulphide solution obtained in the precarbonation step and partly from the non-crystallized alkali carbonate solution, feeding at least a portion of the alkali carbonate -- alkali sulphide solution through the carbonation step, and passing the carbon dioxide rich gas first through the carbonation step and thereafter through the precarbonation step.

Abstract: An aqueous regenerative SO.sub.2 scrubbing system is provided which has a scrubbing loop and a regeneration loop. The scrubbing loop contains a scrubber through which a thiosulfate-rich aqueous solution containing an alkali metal carbonate continuously circulates under sulfite-forming conditions. The sulfute in the spent absorbent solution is converted to thiosulfate in a sulfite conversion zone located in the scrubbing loop but outside the scrubber. The sulfite conversion is effected by means of a reducing agent containing a water soluble alkali metal hydrosulfite as the essential sulfite reducing agent. The regeneration loop serves to convert the incremental portion of thiosulfate formed in the scrubbing loop to H.sub.2 S and an aqueous solution containing the required amounts of alkali metal carbonate and of alkali metal hydrosulfide for the scrubbing loop.

Abstract: A continuous cyclic process for removing sulfur dioxide from gases produced in the combustion of fossil fuels or in chemical and metallurgical operations by means of an aqueous solution including the carbonate of an alkali metal to absorb said oxide out of said gases whereby the metal carbonate is converted into the metal sulfite. A two step recovery process is employed to reproduce the aqueous carbonate solution for reuse in the absorption step and to produce hydrogen sulfide which may be converted into elemental sulfur by well known means, if desired.

Abstract: A solution of sodium sulfite or sulfide is reacted with ammonium sulfate, so as to produce a gas containing SO.sub.2 or H.sub.2 S, NH.sub.3 and H.sub.2 O, which is thereafter treated for sulfur production and NH.sub.3 recovery, and a liquid outflow containing sodium sulfate which is reacted with CO.sub.2 and NH.sub.3, in order to produce NaHCO.sub.3 and regenerate the ammonium sulfate. NaHCO.sub.3 may be converted to sodium carbonate and CO.sub.2, the latter being re-used in the process.

Abstract: A process is described whereby accumulated impurities, consisting mainly of sodium tiocyanate are continuously removed from scrubbing liquors used for removal of hydrogen sulphide from fuel gases and the liquors thereby regenerated and re-used in the hydrogen sulphide scrubbing operation. The thiocyanate is removed by contacting the used scrubbing liquor with an organic solvent, e.g. n-butanol, separating the thiocyanate-bearing solvent from the scrubbing liquor, re-using the treated scrubbing liquor, recovering the thiocyanate from the solvent and re-using the solvent. The extracted sodium thiocyanate can be converted to pure, saleable chemicals or converted to an alkali which can be re-used in the absorbing liquors, thereby producing a completely closed system with no effluent.

Abstract: Process for purifying industrial gases containing hydrogen sulfide and for simultaneously producing elemental sulfur, comprising contacting said gases with an aqueous solution of sodium hydroxide and/or sodium carbonate, thereby forming a sodium sulfide solution, contacting said solution with an aqueous solution of ammonium hydrogen carbonate or with a gaseous mixture of CO.sub.2 and NH.sub.3 so as to precipitate sodium hydrogen carbonate, decomposing the latter to CO.sub.2 and neutral sodium carbonate which is recycled, heating the resulting liquid phase to produce NH.sub.3 and H.sub.2 S and producing sulfur by reacting the H.sub.2 S with sulfurous anhydride.

Abstract: A process for treating a hydrogen sulfide-containing gas in a closed loop system wherein said gas is passed through and absorbed by an alkaline aqueous absorbent containing an alkali carbonate and an oxidation catalyst. The solution containing the dissolved hydrogen sulfide is oxidized with an oxygen-containing gas to convert the absorbed hydrogen sulfide into elementary sulfur and sulfur salt compounds. After separation of the elementary sulfur from the solution, the solution is re-circulated for use as alkaline absorbent. A part of the re-circulated solution is diverted and subjected to mixed-combustion with an auxiliary fuel in a combustion furnace at an air ratio lower than 0.9 and at a temperature of 700.degree.C to 1100.degree.C to thermally decompose the sulfur compounds into hydrogen sulfide and an alkali carbonate.

Abstract: A method is shown for removing sulfur dioxide from a hot flue gas by absorption of the sulfur dioxide in an aqueous solution or slurry containing no more than 40 wt.% of an alkali metal carbonate or bicarbonate, preferably sodium carbonate and/or sodium bicarbonate using a spray-dryer scrubber to produce a dry mixture of sodium sulfite, sodium sulfate, and sodium carbonate and/or bicarbonate. Such a mixture is directly suitable as a feed to a regeneration stage.It is particularly preferred to regenerate the absorbent and recover commercial sulfur values in a closed-cycle process by next treating the solid absorption product in a molten salt reduction step with a reducing agent, preferably a carbonaceous material, to reduce the sodium sulfite and sulfate to sodium sulfide. Concurrently, a source of oxygen is fed to the reducer to generate sufficient heat therein for the reduction step by a combustion reaction.

Abstract: A continuous cyclic process and apparatus for removing sulfur dioxide (and if present, sulfur trioxide) from gases produced in the combustion of fossil fuels or in chemical and metallurgical processes by means of an aqueous absorption solution including potassium carbonate to absorb said oxides out of said gases whereby potassium carbonate is converted into potassium sulfite (sulfate). A two component, two stage molten process is employed to recover potassium carbonate for reuse in the absorption step and to liberate hydrogen sulfide which may be converted to elemental sulfur by well known methods.