Abstract: The invention relates to a process for recovering the sulfur components of acidic gases collected by gas desulfurization. The inventive concept is to first compress a stream of the acidic gas (known as "acid gas") up to a pressure of 8.00 to 12.00 atmospheres absolute. Then this compressed stream of gas is cooled to -35.degree. to -45.degree. C. The pressure on this cooled gas is reduced to a pressure of 1.05 to 2.00 atmospheres absolute. Subsequently, the gas is further cooled to a temperature of -55.degree. to -65.degree. C. Finally, the resulting mixture is conducted to a separator where frozen solid constituents are separated from the gaseous constituents. The gaseous constituents include substantially all of the sulfides produced during the gas desulfurization and the frozen solid particles consist essentially of carbon dioxide.

Abstract: The amount of sulfur oxides in flue gas evolved in a catalyst regenerator in a catalytic cracking system is lowered by incorporating into the cracking catalyst, before using the catalyst in the cracking system, finely divided, high surface area alumina which has been calcined at 700.degree.-1600.degree.0 F. before incorporation into the catalyst. Sulfur oxides react with the calcined alumina in the regenerator to form a sulfur-containing solid. The sulfur-containing solid reacts with hydrocarbon to form fluid sulfur compounds in the FCC reactor, and the sulfur compounds exit the reactor mixed with the cracked hydrocarbons.

Abstract: Sulfur oxides in flue gas formed during cracking catalyst regeneration are reacted with a zeolitic crystalline aluminosilicate containing sodium cations in the catalyst regenerator to form a sulfur-containing solid, and the sulfur component is removed from the crystalline aluminosilicate in the cracking reactor by contacting the sulfur-containing solid with the hydrocarbon feed.

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 The product liquor is withdrawn from the neutralization zone and introduced into a carbonation zone where it is contacted with a sufficient amount of a CO.sub.2 -containing gas to produce a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: Alkali metal sulfides are regenerated from alkali metal hydrosulfides which are produced as a result of the hydroconversion of heavy carbonaceous feeds. The regeneration is effected by contacting the alkali metal hydrosulfide with a metal oxide at elevated temperatures.

Abstract: An improved process for the reduction of SO.sub.2 is provided in which a gas containing SO.sub.2 is contacted with granular coal in the presence of steam.

Abstract: Alkali metal sulfides are regenerated from alkali metal hydrosulfides which are produced as a result of the hydroconversion of heavy carbonaceous feeds. The regeneration is effected by treating the spent solids from a hydroconversion reactor, said solids containing an alkali metal hydrosulfide, with water and carbon dioxide at a temperature and pressure sufficient to convert about 50% of the alkali metal hydrosulfide to an alkali metal carbonate, and heating a mixture of said alkali metal carbonate and unreacted alkali metal hydrosulfide with a quantity of coke to an elevated temperature sufficient to cause reaction of the hydrosulfide with the carbonate whereby an alkali metal sulfide is formed.

Abstract: A hydrocarbon is partially oxidized in the presence of steam and oxygen in a high temperature reducing flame zone to which sulfur is added in excess of the quantity of hydrogen and carbon monoxide formed to generate a second flame zone. The gas stream is rapidly cooled to prevent further reactions, then further cooled to condense sulfur to the extent of providing unreacted hydrogen and carbon monoxide in a molar excess over the residual sulfur present in the gas stream. The resultant gas stream is passed to a catalytic conversion zone where residual sulfur and carbonyl sulfide are converted to hydrogen sulfide. A formed gas stream free of sulfur and sulfur dioxide may be cooled to below the dew point of water to remove water prior to use.

Abstract: This invention is a 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 Na.sub.2 CO.sub.3 to form Na.sub.2 SO.sub.3, (2) reducing the Na.sub.2 SO.sub.3 to Na.sub.2 S, (3) reacting the Na.sub.2 S with NaHCO.sub.3 to form H.sub.2 S and Na.sub.2 CO.sub.3, (4) recycling part of the Na.sub.2 CO.sub.3 to the SO.sub.2 reaction step, (5) reacting the remainder of the Na.sub.2 CO.sub.3 with CO.sub.2 and H.sub.2 O to form NaHCO.sub.3 and (6) recycling the NaHCO.sub.3 to the H.sub.2 S formation reaction.

Abstract: Flue gas having a content of sulfur dioxide is passed upwardly through a scrubbing tower against a descending flow of recycled aqueous sodium aluminate-sodium hydroxide liquor. The sulfur dioxide in the gas is converted to sodium and aluminum sulfates and sulfites and the liquor removes any fly ash present in the gas. Underflow is continuously discharged from the tower and is sent to an evaporator for removal of excess water. Make-up solutions of sodiuum hydroxide, sodium sulfate and aluminum sulfate are added, as necessary. Carbonaceous reducing agent is added to the discharge from the evaporator. The mixture is continuously fed into a reducing furnace where the sulfates and sulfites are reduced to sulfides. The product of the furnace (molten sodium and aluminum sulfides) is charged into a continuous hydrolyzer. Hydrogen sulfide is evolved and collected, and, if desired, its sulfur content is converted to elementary sulfur. The underflow from the hydrolyzer is filtered.

Abstract: A heavy water production stage in a bithermal H.sub.2 S gas - H.sub.2 O liquid exchange plant wherein the cold tower is operated under temperature and pressure conditions such that H.sub.2 S in the liquid phase is formed and is maintained in the separation units (sieve trays or plates) of the cold tower. It has been found that the presence of liquid H.sub.2 S acts as an efficient anti-foaming agent.

Abstract: Certain impure streams, especially those from geothermal sources, are polluted with hydrogen sulfide, ammonia, carbon dioxide, other gases, and finely divided particulate solid matter in a form resembling dust or smoke. These contaminants reduce the efficiency of the steam as a heat transfer fluid, are detrimental to equipment utilizing steam as an energy source, and result in environmental pollution or expensive requirements for limiting the same. Herein so polluted steam is selectively processed in the gaseous state upstream of said equipment to remove hydrogen sulfide therefrom, with or without removing other pollutants, to recover valuable materials therefrom, and to improve the utility of the steam as an energy source. This is done by contacting a flow of the steam with aqueous liquid reactant media consisting essentially of one or more reactive compounds of certain metals which form solid metal sulfide reaction products and which preferably are electropositive with respect to hydrogen.

Abstract: Carbon monoxide and sulfur oxides are removed from flue gas produced in a catalyst regenerator in an FCC system and sulfur from the flue gas is shifted to form hydrogen sulfide, which is recovered in the gases removed from the cracking reactor in the system by reacting carbon monoxide in the regenerator flue gas with oxygen in contact with a particulate carbon monoxide combustion promoter, reacting sulfur oxides in the regenerator flue gas with particulate alumina physically mixed with the FCC catalyst to form a sulfur-containing solid, and forming hydrogen sulfide in the cracking reactor by contacting the sulfur-containing solid with the hydrocarbon feed.

Abstract: Sulfur oxides are removed from flue gas in a catalyst regenerator in a fluid catalyst cracking system while liquid-hydrocarbon product yield from the system is maintained at a high level by heating a particulate silica-containing cracking catalyst to 800-1500.degree. F; impregnating 0.1 to 25 weight percent aluminum onto the catalyst particles; and cycling the resulting particles through the cracking reactor and catalyst regenerator in the cracking system.

Abstract: A dual temperature exchange system, wherein, inter alia, the feed supply substance traverses selected portions of one of the two temperature zones, said selected portions being correlated with the availability and/or cost of a supply of the feed substance concerned is disclosed, and in connection therewith also disclosed is an improved system for humidification and dehumidification of a gaseous flow by effecting evaporation of a vaporizable liquid thereinto with the aid of heat recovered from the subsequent condensation from said gaseous flow of vaporized liquid carried thereby.

Abstract: The hydrolysis of carbon oxysulfide is catalyzed by piperazinone and alkyl-substituted piperazinones at ambient or below ambient temperatures. The hydrolysis step can be combined with a sour gas purification process in the treatment of refinery gases, coal gasification streams, and other such gases which contain COS and other acidic contaminants.

Abstract: Fuel gases such as those produced in the gasification of coal are stripped of sulfur compounds and particulate matter by contact with molten metal salt. The fuel gas and salt are intimately mixed by passage through a venturi or other constriction in which the fuel gas entrains the molten salt as dispersed droplets to a gas-liquid separator. The separated molten salt is divided into a major and a minor flow portion with the minor flow portion passing on to a regenerator in which it is contacted with steam and carbon dioxide as strip gas to remove sulfur compounds. The strip gas is further processed to recover sulfur. The depleted, minor flow portion of salt is passed again into contact with the fuel gas for further sulfur removal from the gas. The sulfur depleted, fuel gas then flows through a solid absorbent for removal of salt droplets. The minor flow portion of the molten salt is then recombined with the major flow portion for feed to the venturi.

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: A dual temperature extraction apparatus comprising a hot and cold tower with liquid and gas streams passing in countercurrent deuterium exchange relation therein, the gas being recycled from the top of the cold tower to the bottom of the hot tower, a humidifier section through which the said recycled gas stream and also the liquid stream from the hot tower passes, a dehumidifier between hot and cold tower through which both gas and liquid streams pass, means for heat exchange between humidifier and dehumidifier, means for heating cold inlet feed liquid and feeding it to the system at the top of the dehumidifier section at a point between the liquid outlet of the hot tower and the liquid input to the humidifier, means for recovering heat from a first portion of the liquid stream leaving the humidifier and passing the stream to waste, means for recycling a second portion of the liquid stream leaving the humidifier to the top of the cold tower, said humidifier section comprising a humidifier recycle section and

Abstract: A liquid feed and effluent system to recover dissolved process gas (e.g. H.sub.2 S) from an effluent process liquid (e.g. water), which liquid may also contain dissolved solid components (e.g. soluble salts); the system heats the feed liquid with heat recovered from the effluent liquid, saturates the so heated feed liquid with process gas, which gas may also contain inert gas components, and separately discharges from the system such inert gas components and effluent liquid from which process gas and heat have been recovered. In the combination the dissolved process gas is preferably recovered from the effluent liquid by flashing at progressively reduced pressures and final vapor stripping thereof at the most reduced pressure.

Abstract: Sulfur oxides are removed from a gas and the sulfur is converted to hydrogen sulfide by the steps of: (1) reacting sulfur oxides in the gas with alumina to form a solid sulfur-containing compound and remove sulfur oxides from the gas; and (2) contacting the solid compound resulting from step (1) with a hydrocarbon at a temperature of about 800.degree.-1300.degree. F and reacting the solid sulfur-containing compound with components of the hydrocarbon to form hydrogen sulfide.

Abstract: A process is disclosed whereby NO.sub.x and SO.sub.x components contained in stack gases are simultaneously reduced to N.sub.2 and H.sub.2 S, respectively, by passing said stack gases (which also contain steam and usually some oxygen) over bituminous coke at between about 900.degree. and 1600.degree. F.

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: In a two or more stage isotope separation plant using hydrogen sulfide and water in hot and cold exchange zones, for the separation of deuterium (heavy water), in which one first stage portion passes isotope enriched fluid in the form of gas to a second dual temperature isotope concentration stage, the enrichment throughput of the second stage is supplemented by also passing isotope enriched liquid to the second stage. This permits enlargement of an existing plant by expansion of the first stage capacityonly, and providing carry-over of enrichment to the unenlarged second stage in the form of gas and liquid.This invention is directed to an isotope separation process, and to apparatus for carrying out the process. In particular the invention is directed to the separation of deuterium oxide from water, using a water-hydrogen sulphide counterflow arrangement.

Abstract: The salt of a weak acid and a weak base is removed from a solution by contacting said solution with an emulsion. Said emulsion comprises an exterior phase which is characterized as immiscible with said solution and permeable to the weak acid and/or weak base in their un-ionized forms. One of the species which can permeate through said exterior phase reacts with a reactant present in the interior phase of the emulsion which converts said permeating species to a non-permeable form, i.e., by neutralization, thus providing a continuing driving force for the permeation of said permeating species. The other nonreacting or nonpermeating species is stripped from solution by passing an inert gas through said solution. Stripping and neutralization in the interior phase of the emulsion are carried out simultaneously.

Abstract: A method for reducing sulfur dioxide wherein ammonia is used as the reducing agent. The reduction may be accomplished either thermally or catalytically and the principal products obtained will be elemental sulfur and/or hydrogen sulfide, depending principally upon the particular conditions and relative reactant concentrations actually employed. The sulfur dioxide may be derived from essentially any source. In a preferred embodiment, however, the sulfur dioxide will be derived from a flue gas stream and the same will be separated therefrom with an absorption process wherein ammonia (on an aqueous ammoniacal solution) is also used as the absorbent.

Abstract: A dual temperature isotope exchange process of the type having a first stage comprising a hot and a cold tower with liquid and gas passing in countercurrent exchange relation therein, the gas being recycled from the top of the cold tower to the bottom of the hot tower via a humidifier section through which a liquid stream also passes, a dehumidifier between hot and cold towers through which both gas and liquid streams pass, the improvement comprising the feeding of the inlet feed liquid at a raised temperature to the top of the humidifier section that is, to a point between the liquid outlet of the hot tower and the liquid input to the humidifier and the recycling of a portion of the liquid leaving the hot tower to the top of the cold tower preferably via a cooling device.

Abstract: A dual temperature final enrichment system which, e.g., can effect the further enrichment of the previously augmented deuterium content of water from a concentration of 1 mol percent to a desired concentration of up to 99.8 mol percent; and a product finishing system which can remove dissolved contaminants from such enriched water to provide a high purity product.

Abstract: Carbon oxysulfide is obtained in high yield and with high product selectivity and conversion rates by the sulfurization of methanol in the gas phase at elevated temperatures. The starting methanol utilized in the process may be advantageously supplied from natural gas generated at petroleum production sites.

Abstract: The instant invention relates to a process for the removal of sulfur oxides from gases which comprises the steps of contacting the gas with a cerium oxide sorbent at conditions whereby the sulphur oxides present in the gas are sorbed by said cerium oxide sorbent and regenerating said cerium oxide sorbent by contacting with a reducing atmosphere at conditions whereby the sorbent is substantially converted to a sulfur-free state. The gas may be an exhaust gas, e.g. from an automobile or a flue gas. This invention is especially preferred for treating flue gas. In this preferred embodiment, the flue gas may be contacted with the cerium oxide sorbent at a temperature of from 300.degree. to 800.degree. C. to form cerium sulfate and/or sulfite and the sorbent is regenerated by contacting with a reducing gas, for example, hydrogen in admixture with steam or other inert gases at a temperature of from 500.degree. to 800.degree. C. to convert the cerium sulfate or sulfite to cerium oxide.

Abstract: A stable unsubstituted sulfonium salt and method of isolating same.

Abstract: Chalcopyrite is decomposed by treatment with aqueous acid solution and a metallic reductant to form either metallic copper or copper sulfide, ferrous iron and hydrogen sulfide.

Abstract: Hydrogen sulphide is stripped from hot effluent, in a heavy water separation plant of the dual temperature isotope separation type, by taking liquid effluent from the hot tower before passage through the humidifier, passing the liquid through one or more throttle devices to flash-off the H.sub.2 S gas content, and feeding the gas into an absorption tower containing incoming feed water, for recycling of the gas through the process.

Abstract: A method for producing carbon disulfide by sulfurization of sulfur-containing organic compounds is described. Conventional apparatus may be employed with realization of reactant conversion rates approaching 100%, and production of undesirable by-products is insignificant.

Abstract: Hydrogen sulfide and its precursors can be selectively sorbed from gas streams containing same by contacting the gas stream at elevated temperatures with a regenerable sorbent comprising a supported or unsupported lanthanum or rare earth metal component. Subsequent to sorption, the sorbent may be desorbed and regenerated by treatment with steam (desorption) and an oxidizing gas (regeneration). The sorbent capacity may be increased by the use of alkali or alkaline earth metal components as promoters.

Abstract: A water-insoluble exchange agent is used to remove barium from aqueous barium sulfide and then to release the barium to aqueous alkali, forming an aqueous solution from which there is crystallized substantially pure Ba(OH).sub.2, 8H.sub.2 O, particularly useful as an ingredient of "barium greases". The preferred exchange agent is di(2-ethylhexyl)phosphoric acid, which can be regenerated and recycled.

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: The invention is a method for preparing hydrogen sulfide by reacting a gas mixture containing carbon monoxide with sulfur to provide a gas mixture containing carbonyl sulfide and reacting the gas mixture containing carbonyl sulfide with water in the vapor phase to provide a gas mixture containing hydrogen sulfide. The process is preferrably operated continuously. The water can be present in the step in which the carbon monoxide is reacted with the sulfur.

Abstract: A process for recovering the calcium values and sulfide values from a calcium sulfide-containing material is disclosed. The calcium sulfide-containing material dispersed in an aqueous medium is digested in the presence of hydrogen sulfide under conditions to provide a mole ratio of S.sup.-.sup.-/Ca.sup.+.sup.+ of between 1.5 and 2.0. After filtration to remove undissolved solids, the mother liquor is stripped with an inert gaseous medium, e.g. nitrogen, steam, etc., whereby hydrogen sulfide is stripped therefrom with the concomitant formation of calcium hydroxide which is subsequently separated by filtration. The gaseous overhead from the stripping operations may be fractionated to form a recycleable hydrogen sulfide-containing stream.

Abstract: Antimony sulfide contained in an antimony sulfide bearing ore, such as stibnite, is converted to high purity antimony trichloride by reacting the antimony sulfide bearing ore with a source of chlorine to form high purity antimony trichloride and sulfur or hydrogen sulfide as separable by-products. The high purity antimony trichloride may be hydrolyzed to form high purity antimony oxide.

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 fluid treatment system including (a) the heating of a flow of carrier gas and the simultaneous vaporization thereinto of a liquid to be carried thereby in a first zone, and (b) the subsequent cooling of such flow and condensation of liquid therefrom in a third zone after the same has been subjected to a treatment including further heating and saturation of the gas with vapor of the liquid in a second zone, the principal proportion of the heat required being supplied in the first zone by transfer from the third zone by way of at least one indirect contact heat exchange. In particular embodiments the indirect contact heat exchange is effected with at least one circulation of liquid passing in countercurrent direct contact heat exchange with the gas. In particular embodiments special advantages are obtained by controlling the temperature of the condensate formed in the third zone by co-current or counter-current flow thereof with respect to the gas being cooled therein.

Abstract: This invention comprises a method for the separation of one component or more from a vapor or gas mixture which involves the step of reacting the component to form a complex or thermally decomposible molecule by reaction with a compound adsorbed or otherwise deposited on a solid carrier. Typical of the gas components that can be so removed, and recovered if desired are carbon dioxide, oxygen, nitrogen oxide, carbon monoxide, sulfur dioxide, silicon tetrafluoride, hydrogen sulfide, aromatic hydrocarbons, mercaptans, HCN, HF, HCl, BF.sub.3 and HBr. Compounds which are adsorbed on the solid carrier for reaction with these various components include various carbonates, such as K, Na, Li, Ca, Cd, Ba; various sulfites, such as K, Na, Li, Cd and Ag; fluorides, glyoximes, ferrous and cupric salts, cuprous amine complexes, dioxane, urea, phosphates, chlorinated aromatics, organic nitriles, benzaldehyde, quinols, etc.

Abstract: Improvements in method for isotope concentration by dual temperature exchange between feed and auxiliary fluids in a multistage system, in a preferred embodiment of which the first flulid is a vaporizable liquid and the auxiliary fluid a gas, comprising steps for improving the heating and/or cooling and/or humidifying and/or dehumidifying operations.

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.

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.