Abstract: A combination of at least one basic compound, such as potassium hydroxide, together with at least one aldehyde donor can synergistically scavenge mercaptans from organic fluids, such as hydrocarbons, where “synergistically effective” is defined as the amount of mercaptans scavenged is greater as compared with a combination where either the basic compound or the reaction product is absent, used in the same total amount.

Abstract: A method of synthesizing a disulfide compound is provided. The method may include providing an electrochemical cell that has a compartment, an anode, and a cathode. The compartment may contain a solution of one or more thiol compounds, a catalyst, and a solvent. The method may also include providing an electrical current to the electrochemical cell and converting the one or more thiol compounds into the disulfide compound.

Abstract: Automated systems to make target compounds from slide stainer waste streams inactive utilizing advanced oxidation processes are described herein. Advanced oxidation processes are promoted by UV irradiation and further accelerated by use of radical initiators, such as hydrogen peroxide. The automated systems further include mechanisms for segregating components of the waste streams.

Abstract: The present invention relates to the field of the extraction of sulphur-containing compounds such as the mercaptans, COS or H2S from a hydrocarbon-containing cut. This selective extraction is carried out by bringing the hydrocarbon-containing cut in liquid phase into contact with an alkaline solution, for example soda. The process according to the invention is an improved process for the regeneration of the alkaline solution, making it possible to reduce the quantity of alkaline solution required in the regeneration section.

Abstract: A caustic desulfonylation method and system comprising a reactor vessel with a solid carbonaceous selectivity promoter provided therein, a liquid feed input of the reactor vessel configured to receive a source of caustic, a hydrocarbon feed comprising oxidized sulfur containing compounds and a gas feed input of the reactor vessel configured to receive a source of hydrogen. The caustic desulfonylation method and system further includes an output of the reactor vessel releasing the caustic and an upgraded hydrocarbon product with sulfur content less than the sulfur content of the hydrocarbon feed received by the liquid feed of the reactor vessel.

Abstract: The invention involves an integrated process in which a hydrocarbon feedstock is treated with a caustic (alkaline) extraction to remove sulfides, disulfides, and mercaptans. These extracted materials are further treated, and are then used to activate hydrotreating catalysts.

Abstract: The invention involves an integrated process in which a hydrocarbon feedstock is treated with a caustic (alkaline) extraction to remove sulfides, disulfides, and mercaptans. These extracted materials are further treated, and are then used to activate hydrotreating catalysts.

Abstract: The present invention is a process for desulfurizing hydrocarbon feedstreams with alkali metal compounds and regenerating the alkali metal compounds via the use of a copper sulfide reagent. The present invention employs the use of a copper sulfide reagent to convert alkali metal hydrosulfides in the generation or regeneration of the alkali hydroxide compounds which may be utilized in a desulfurization process for hydrocarbon feedstreams. Additionally, in preferred embodiments of the processes disclosed herein, carbonates which form as byproducts of the desulfurization process, and are non-regenerable with copper sulfide, are removed from the alkali hydroxide stream.

Abstract: A process for upgrading an oil feedstock includes reacting the oil feedstock with a quantity of an alkali metal, wherein the reaction produces solid materials and liquid materials. The solid materials are separated from the liquid materials. The solid materials may be washed and heat treated by heating the materials to a temperature above 400° C. The heat treating occurs in an atmosphere that has low oxygen and water content. Once heat treated, the solid materials are added to a solution comprising a polar solvent, where sulfide, hydrogen sulfide or polysulfide anions dissolve. The solution comprising polar solvent is then added to an electrolytic cell, which during operation, produces alkali metal and sulfur.

Abstract: Hydrocarbon feedstreams are desulfurized using an alkali metal reagent, optionally in the presence of hydrogen. Improved control over reaction conditions can be achieved in part by controlling the particle size of the alkali metal salt and by using multiple desulfurization reactors. After separation of the spent alkali metal reagent, the resulting product can have suitable characteristics for pipeline transport and/or further refinery processing.

Abstract: The present invention is a process for desulfurizing hydrocarbon feedstreams with alkali metal compounds and regenerating the alkali metal compounds via the use of a transition metal oxide. The present invention employs the use of a transition metal oxide, preferably copper oxide, in order to convert spent alkali metal hydrosulfides in the regeneration of the alkali hydroxide compounds for reutilization in the desulfurization process for the hydrocarbon feedstreams. Additionally, in preferred embodiments of the processes disclosed herein, carbonates which may be detrimental to the overall desulfurization process and related equipment are removed from the regenerated alkali metal stream.

Abstract: The present invention relates to a process for regeneration of alkali metal salt reagent used in desulfurization of heavy oil feedstreams. In particular, the present invention relates to a process utilizing potassium hydroxide as an external supply reagent to a heavy oil conversion process and in-situ conversion of the spent reactants utilized in such process into a potassium sulfide reagent for reintroduction into the heavy oil conversion process.

Abstract: One exemplary embodiment can be a process for removing one or more disulfide compounds from a caustic stream. The process can include passing the caustic stream, previously contacted with a hydrocarbon stream for removing one or more mercaptans, through a column to remove the one or more disulfide compounds downstream of a mercaptan oxidation zone.

Abstract: In some embodiments, the invention is a method of removing sulfur from a hydrocarbon feed using the steps of dissolving metallic sodium in a first solvent, combining the sodium/first solvent solution with a sulfur-free alkane or cycloalkane second solvent, vaporizing the first solvent from sodium/first solvent/second solvent combination to transfer the dissolved metallic sodium into the second solvent, and then combine the resultant liquid with a liquid hydrocarbon feed containing an organosulfur species. The resulting stream is combined with a hydrogen donor. The combination is heated and pressurized to form a liquid hydrocarbon product containing sodium sulfide. The liquid hydrocarbon product containing sodium sulfide is then cooled, and the sodium sulfide is extracted. The extracted sodium sulfide is then processed in a sodium sulfur cell to regenerate the sodium and recycle it to the feed.

Abstract: A process for upgrading an oil feedstock includes reacting the oil feedstock with a quantity of an alkali metal, wherein the reaction produces solid materials and liquid materials. The solid materials are separated from the liquid materials. The solid materials may be washed and heat treated by heating the materials to a temperature above 400° C. The heat treating occurs in an atmosphere that has low oxygen and water content. Once heat treated, the solid materials are added to a solution comprising a polar solvent, where sulfide, hydrogen sulfide or polysulfide anions dissolve. The solution comprising polar solvent is then added to an electrolytic cell, which during operation, produces alkali metal and sulfur.

Abstract: After desulfurizing a hydrocarbon feedstream using an alkali metal reagent, the hydrocarbon feedstream can include particles of spent alkali metal salts. The spent alkali metal salts can be separated from the hydrocarbon feedstream and regenerated to form an alkali metal reagent, such as a alkali hydroxide or alkali sulfide. The regeneration process can pass through an intermediate stage of forming an alkali carbonate by successive reactions with carbon dioxide and calcium oxide. The calcium oxide can also be regenerated.

Abstract: The present invention is a process for desulfurizing hydrocarbon feedstreams with alkali metal compounds and regenerating the alkali metal compounds via the use of a copper metal reagent. The present invention employs the use of a copper metal reagent to convert spent alkali metal hydrosulfides in the regeneration of the alkali hydroxide compounds for reutilization in the desulfurization process for the hydrocarbon feedstreams. Additionally, in preferred embodiments of the processes disclosed herein, carbonates which may be detrimental to the overall desulfurization process and related equipment are removed from the regenerated alkali metal stream.

Abstract: One exemplary embodiment can be a process for reducing corrosion during removal of one or more sulfur-containing hydrocarbons from a gas. Generally, the process includes producing an effluent including a caustic, one or more hydrocarbons, one or more sulfur compounds, and a gas from an oxidation vessel; sending the effluent to a stack of a disulfide separator; passing the gas, including oxygen and one or more sulfur compounds, through the stack; and passing a stream including one or more hydrocarbons to the stack at a temperature of less than about 38° C. for absorbing the one or more sulfur compounds. Typically, the stack includes one or more walls surrounding a void and adapted to receive a fluid including one or more phases, a packed bed positioned within the void, and a distributor including one or more risers and one or more compartments coupled to a substantially horizontal member forming a plurality of apertures there-through.

Abstract: The liquid hydrocarbon stream including COS is introduced via line 1 into membrane contactor CM to be placed in contact, through membrane M, with the aqueous alkanolamine solution arriving via line 3. The COS contained in the hydrocarbon stream is absorbed by the aqueous alkanolamine solution. The liquid hydrocarbons from which the COS has been removed are evacuated from CM via line 2. The aqueous solution containing COS is sent via line 4 to zone R to be regenerated. The compounds released during regeneration, particularly COS and COS-derived products, are evacuated from zone R via line 5. The regenerated aqueous alkanolamine solution is recycled via line 3 into membrane contactor CM.

Abstract: A process for the removal of residual sulfur compounds from a liquid caustic stream is disclosed. One embodiment of my invention adsorbs disulfides from a caustic stream using an activated carbon adsorbent while another combines both oxidation and adsorption in single step to remove residual sulfur compounds from a rich caustic stream using metal phthalocyanine supported on a solid adsorbent. This process is especially useful as a polishing step in a caustic regeneration process flow scheme.

Abstract: The present invention relates to a process for desulfurizing bitumen and other heavy oils such as low API gravity, high viscosity crudes, tar sands bitumen, or shale oils with alkali metal compounds under conditions to promote in-situ regeneration of the alkali metal compounds. The present invention employs the use of superheated water and hydrogen under conditions to improve the desulfurization and alkali metal hydroxide regeneration kinetics at sub-critical temperatures.

Abstract: In some embodiments, the invention is a method of removing sulfur from a hydrocarbon feed using the steps of dissolving metallic sodium in a first solvent, combining the sodium/first solvent solution with a sulfur-free alkane or cycloalkane second solvent, vaporizing the first solvent from sodium/first solvent/second solvent combination to transfer the dissolved metallic sodium into the second solvent, and then combine the resultant liquid with a liquid hydrocarbon feed containing an organosulfur species. The resulting stream is combined with a hydrogen donor. The combination is heated and pressurized to form a liquid hydrocarbon product containing sodium sulfide. The liquid hydrocarbon product containing sodium sulfide is then cooled, and the sodium sulfide is extracted. The extracted sodium sulfide is then processed in a sodium sulfur cell to regenerate the sodium and recycle it to the feed.

Abstract: The present invention is a process for desulfurizing hydrocarbon feedstreams with alkali metal compounds and regenerating the alkali metal compounds via the use of a copper sulfide reagent. The present invention employs the use of a copper sulfide reagent to convert alkali metal hydrosulfides in the generation or regeneration of the alkali hydroxide compounds which may be utilized in a desulfurization process for hydrocarbon feedstreams. Additionally, in preferred embodiments of the processes disclosed herein, carbonates which form as byproducts of the desulfurization process, and are non-regenerable with copper sulfide, are removed from the alkali hydroxide stream.

Abstract: The present invention is a process for desulfurizing hydrocarbon feedstreams with alkali metal compounds and regenerating the alkali metal compounds via the use of a transition metal oxide. The present invention employs the use of a transition metal oxide, preferably copper oxide, in order to convert spent alkali metal hydrosulfides in the regeneration of the alkali hydroxide compounds for reutilization in the desulfurization process for the hydrocarbon feedstreams. Additionally, in preferred embodiments of the processes disclosed herein, carbonates which may be detrimental to the overall desulfurization process and related equipment are removed from the regenerated alkali metal stream.

Abstract: The present invention is a process for desulfurizing hydrocarbon feedstreams with alkali metal compounds and regenerating the alkali metal compounds via the use of a copper metal reagent. The present invention employs the use of a copper metal reagent to convert spent alkali metal hydrosulfides in the regeneration of the alkali hydroxide compounds for reutilization in the desulfurization process for the hydrocarbon feedstreams. Additionally, in preferred embodiments of the processes disclosed herein, carbonates which may be detrimental to the overall desulfurization process and related equipment are removed from the regenerated alkali metal stream.

Abstract: In some embodiments, the invention is a method of removing sulfur from a hydrocarbon feed using the steps of dissolving metallic sodium in a first solvent, combining the sodium/first solvent solution with a sulfur-free alkane or cycloalkane second solvent, vaporizing the first solvent from sodium/first solvent/second solvent combination to transfer the dissolved metallic sodium into the second solvent, and then combine the resultant liquid with a liquid hydrocarbon feed containing an organosulfur species. The resulting stream is combined with a hydrogen donor. The combination is heated and pressurized to form a liquid hydrocarbon product containing sodium sulfide. The liquid hydrocarbon product containing sodium sulfide is then cooled, and the sodium sulfide is extracted.

Abstract: A caustic recovery system comprising an oxygen source adapted to provide a gas stream comprising at least 30% oxygen. A method of regenerating caustic comprising intermingling spent caustic with a gas stream comprising at least 30% oxygen.

Abstract: The present invention is a method of removing sulphur from a hydrocarbon feed stream, comprising the steps of: (a) dissolving sodium in a liquid solvent to form a solution containing sodium atoms; (b) combining the liquid solution from step (a) with a liquid hydrocarbon feed containing an organosulfur component to form a combined stream at a temperature of addition and at a pressure near or above the vapor pressure of the solvent at the temperature of addition; (c) reacting the combined stream for sufficient reaction time and at sufficient reaction temperature to form a modified composition comprising one or more sulfur-containing species and less of the organosulfur species than had been present in the hydrocarbon feed; (d) extracting a portion of the sulfur-containing species from the modified composition.

Abstract: An apparatus for separating impurities from a liquid by a non-dispersive contacting of a liquid—liquid reactive systems, the liquids being immiscible with each other, having a cylindrical column separated into a first stage and a second stage, a plurality of modules of packed metallic fibers mounted in the first stage of the column on a support, a first distributor provided in the first stage of the column for distributing a first liquid located above the support such that the first liquid completely wets the fibers by capillary action and forms a film thereon, a second distributor fitted at a bottom portion of the second stage for distributing a second liquid containing impurities on to the metallic fibers, wherein the second liquid flows concurrently with said first liquid so that the impurities present in the second liquid react with the first liquid and dissolve therein and a separator connected to a bottom of said column separates the first liquid and purified second liquid.

Abstract: The invention is a method of removing sulfur from a hydrocarbon feed using the steps of dissolving metallic sodium in a solvent and combining the sodium/solvent solution with a liquid hydrocarbon feed containing an organosulfur species. The pressure of combination is above the vapor pressure of the solvent. The combined hydrocarbon feed and solvent solution are placed in a low pressure environment to vaporize the solvent. The resulting stream is combined with hydrogen gas and this stream is heated and pressurized to form a liquid hydrocarbon product containing sodium sulfide. This product is then cooled, and the sodium sulfide is extracted.

Abstract: The invention relates to a composition and method for treating liquid hydrocarbons in order to remove acidic impurities, such as mercaptans, particularly mercaptans having a molecular weight of about C4 (C4H10S=90 g/mole) and higher, such as recombinant mercaptans.

Abstract: The invention relates to a method for treating and upgrading a hydrocarbon containing acidic species such as mercaptans, comprising: (a) contacting the hydrocarbon, in the essential absence of oxygen, with a first phase of a treatment composition containing water, dissolved alkali metal hydroxide, cobalt phthalocyanine sulfonate, and dissolved alkylphenylates and having at least two phases, (i) the first phase containing water, alkali metal alkylphenylate, dissolved alkali metal hydroxide, and dissolved sulfonated cobalt phthalocyanine, and (ii) the second phase containing water and dissolved alkali metal hydroxide; and then (b) separating an upgraded hydrocarbon.

Abstract: The invention relates to a method for desulfurizing naphtha boiling-range hydrocarbons such as cracked naphtha. More particularly, the invention relates to hydrotreating the naphtha under selective hydrotreating conditions, and then removing mercaptans from the hydrotreater effluent using a caustic extractant.

Abstract: A process for removing H2S and mercaptans from a hydrocarbon stream is disclosed. A hydrocarbon stream such as a LPG stream is contacted with a weakly basic stream, e.g., a sodium bicarbonate stream in order to extract the H2S and mercaptans from the hydrocarbon stream into the basic stream. The basic stream is now treated in a reactor containing a sulfide oxidizing microorganism in order to convert the H2S to sulfur and the mercaptans to disulfides. Finally, the sulfur and disulfides are separated from the basic aqueous stream which can be recycled and used to treat a fresh hydrocarbon stream. The treated hydrocarbon stream is purified to the point that it passes the copper strip test, while the purified basic stream contains less than 0.08 g/l of elemental sulfur.

Abstract: A process is disclosed for producing very low sulfur content hydrocarbon streams by contacting a hydrocarbon feedstream with an aqueous alkaline treatment stream which has been regenerated by the biological conversion of sulfur compounds to elemental sulfur. The process is characterized by the step of contacting the partially regenerated aqueous treatment stream with a hydrocarbon wash stream to remove low levels of residual elemental sulfur suspended in the partially regenerated treatment stream.

Abstract: The aqueous wash stream of an electrolytic precipitation system treating natural gas liquid (NGL) is maintained at a pH sufficiently basic to decrease the solubility of iron sulfide in the aqueous wash stream.

Abstract: An alkaline solution containing dissolved sodium sulfides, mercaptides and phenolates is treated with a carbon dioxide-containing solvent in a reaction zone under mass transfer conditions to neutralize effluent alkaline solution and recover processable hydrocarbon values.

Abstract: The present invention relates to a continuous in-situ process for the removal from heavy oils, of organically bound sulfur in the form of mercaptans, sulfides and thiophenes, heteroatoms selected from the group consisting of nitrogen and oxygen and metals selected from the group consisting of nickel, vanadium and iron, comprising the steps of (a) contacting a heavy oil with aqueous sodium hydroxide at a temperature of about 380.degree. to about 450.degree. C. for a time sufficient to form sodium sulfide; (b) contacting said sodium sulfide of step (a) with water and a transition metal for a time and at a temperature sufficient to form transition metal sulfide, sodium hydroxide, hydrogen and impurities; and (c) recirculating said sodium hydroxide from step (b) to step (a) and removing said transition metal sulfide and said impurities, wherein said impurities are iron, vanadium and nickel. Optionally, molecular hydrogen may be added in the first step.

Abstract: The present invention relates to a continuous in-situ process for the removal of organically bound sulfur existing as mercaptans, sulfides and thiophenes comprising the steps of (a) contacting a heavy oil with aqueous sodium hydroxide at a temperature of about 380.degree. C. to about 450.degree. C. for a time sufficient to form sodium sulfide, and (b) steam stripping the sodium sulfide of step (a) at a temperature sufficient to convert said sodium sulfide to sodium hydroxide and recirculating the sodium hydroxide from step (b) back to step (a) and removing hydrogen sulfide and the metals from the organically bound metal complex of the sodium sulfide to convert it back to sodium hydroxide, in which case the sulfur may be recovered as H.sub.2 S rather than the metal sulfide. Optionally, molecular hydrogen may be added in the first step. The present invention is useful in removing organically bound sulfur that has been recognized to be difficult to remove, such as thiophenes.

Abstract: The present invention relates to a process for treating and regenerating a spent caustic solution at ambient temperatures which includes oxidizing the spent caustic stream with an air/ozone gas mixture, followed by irradiating the oxidized spent caustic stream with a broad range of ultraviolet radiation and finally filtering the spent caustic solution.

Abstract: Method and apparatus are described whereby a caustic-treated hydrocarbon feed mixture having a contaminating concentration of water and sulfur compounds is treated by separating the hydrocarbon feed into a first stream and a second stream. The first stream is contacted with an adsorbent material to produce a reactor feed stream having a significant reduction in the concentration of the contaminating water and sulfur compounds. The reactor feed stream is thereafter contacted in the presence of hydrogen under suitable isomerization conditions with an isomerization catalyst to produce an isomerate product.

Abstract: A process for treating hydrocarbons containing mercaptans comprising the steps of contacting a first mercaptan-containing hydrocarbon stream with a first aqueous alkaline solution stream to form a mercaptide-rich aqueous alkaline solution stream and a reduced-mercaptan hydrocarbon stream; combining said mercaptide-rich aqueous alkaline solution stream with a second mercaptan-containing hydrocarbon stream and with oxygen to form a first mixture; oxidizing said mixture to form a second mixture of hydrocarbon, disulfides and aqueous alkaline solution; and separating said second mixture into a disulfide-containing hydrocarbon stream and a regenerated aqueous alkaline solution stream; whereby said second hydrocarbon stream is sweetened and said mercaptide-rich aqueous alkaline solution is regenerated simultaneously in the same step.

Abstract: An adsorption process is disclosed for removal of carbonyl sulfide (COS) from a liquid hydrocarbon which comprises providing an activated alumina adsorbent which has preferably impregnated with a compound selected from the class consisting of one or more alkali metal compounds, one or more alkaline earth metal compounds, or a mixture of such compounds; passing a liquid hydrocarbon containing COS through the activated alumina adsorbent at a flow rate sufficient to adsorb enough COS in the liquid hydrocarbon to lower the COS content of the liquid hydrocarbon to less than 1 ppm; monitoring the effluent liquid hydrocarbon to determine when the capacity of the adsorbent to adsorb the COS has been reached; and then regenerating the activated alumina adsorbent by passing a gas, heated to a temperature of from about 150.degree. to about 300.degree. C., through the adsorbent for a period of time sufficient to remove a substantial amount of the sulfur adsorbed thereon.

Abstract: A process is disclosed for treating a sour hydrocarbon stream comprising extracting the mercaptans contained in said hydrocarbon stream with an alkaline solution in an extraction zone, oxidizing the mercaptans to disulfides in the presence of an oxidation catalyst, separating said disulfide from said alkaline solution, reducing the residual disulfides in said alkaline solution to mercaptans and recycling said alkaline solution to the extraction zone. Two ways are disclosed to effect the reduction of the disulfides to mercaptans: (1) hydrogenation with a supported metal catalyst and (2) electrochemical reduction.

Abstract: An alkaline solution containing mercaptides is regenerated in an improved process wherein the alkaline solution to be regenerated containing a suitable oxidation catalyst is contacted with an oxygen-containing solvent which is immiscible with said alkaline solution in a reaction zone comprising a plurality of fibers positioned longitudinally within a conduit, whereby the two liquids are in contact while concurrently flowing through said reaction zone during which the mercaptides contained in the alkaline solution are oxidized to disulfides and are simultaneously extracted from the alkaline solution into the solvent solution.

Abstract: A process is disclosed for removing mercaptans from highly olefinic feed streams by extraction with an aqueous alkaline solution. The aqueous solution is preferably regenerated by oxidation of extracted mercaptans to disulfides. The invention employs two extraction steps performed on the aqueous solution to limit the passage of olefins or acetylenes into the mercaptan conversion zone and to limit the passage of mercaptans and/or oxygenates into the primary extraction zone.

Abstract: A process for reducing the molecular weight of hydrocarbons using NaAlCl.sub.4 is provided wherein the hydrogen to carbon ratio of the liquid product slate is approximately the same as the feed material. The process comprises contacting the feed material with a molten salt of NaAlCl.sub.4 having substantially no excess aluminum chloride or sodium chloride, preferably at a temperature of at least 660.degree. F., and at a pressure above atmospheric, preferably from about 50 psia to about 2000 psia, depending upon the product slate desired. According to the present invention, heavy hydrocarbons are converted to a liquid product slate wherein the product slate has an average molecular weight substantially lower than the average molecular weight of the hydrocarbon feedstock.

Abstract: A caustic wash process to remove mercaptans from a mixture of hydrocarbons, an improvement comprising washing the regenerated caustic with a fraction of said hydrocarbon to remove residual disulfides to improve the overall removal of sulfur from the hydrocarbon feed stream.

Abstract: A process for reducing the molecular weight of hydrocarbons using NaAlCl.sub.4 is provided wherein the hydrogen to carbon ratio of the product slate is approximately the same as the feed material, comprising contacting the feed material with a molten salt of NaAlCl.sub.4 having a ratio of aluminum chloride to sodium chloride of at least 1:1, preferably at a temperature of at least 660.degree. F., and at a pressure above atmospheric, preferably from about 50 psia to about 2000 psia, depending upon the product slate desired. According to the present invention, heavy hydrocarbons are converted to a liquid product slate wherein substantially all of the liquid components exhibit a molecular weight lower than the molecular weight range exhibited by the hydrocarbon feedstock.

Abstract: A carbonaceous material is subjected to a hydrotreating process in which it is desulfurized, deasphalted and demetallized by reaction with hydrogen in a molten medium in the presence of potassium hydroxide and water. The water is present in an amount sufficient to minimize the formation of gaseous hydrocarbonaceous products but insufficient to significantly reduce the effectiveness of potassium hydroxide as the hydrotreating agent. The process is characterized by producing a very small amount of gaseous hydrocarbonaceous products, desulfurizing the carbonaceous feed to the extent of at least about 80%, deasphalting the feed to the extent of at least about 60%, and demetallizing the feed to the extent of at least about 90%. In a preferred embodiment, spent potassium hydroxide is regenerated and recycled to the molten medium.