Abstract: A method for removing hydrogen sulfide from a gas stream in a gas-liquid absorber apparatus having two separate absorption sections and utilizing a first absorber alkali solution stream that is a waste sodium carbonate source from a soda ash production facility and a second absorber alkali solution stream that is a process feed stream from a soda ash production facility. The method is particularly well suited for removing H2S from a CO2-containing gas stream generated in a soda ash production facility.

Abstract: A method for removing sulfide from an aqueous alkali solution in which hydrogen peroxide is introduced into a sulfide-containing aqueous alkali solution associated with an alkali mineral recovery operation. The method is particularly useful for the processing of sulfide-containing aqueous alkali solutions containing NaHCO3 and Na2CO3, where bicarbonate in the sulfide-depleted alkali solution is decomposed to form Na2CO3, with concurrent evolution of gaseous carbon dioxide byproduct but without formation of gaseous H2S as a pollutant, and where Na2CO3 values are subsequently recovered from the sulfide-depleted carbonate-rich alkali solution via a crystallization operation.

Abstract: A method of solution mining a subterranean mineral ore deposit such as trona ore in which a borehole is drilled from a subterranean mechanically-worked mineral ore mining operation to connect a mineral ore bed to be solution mined, using subterranean drilling apparatus located proximate to the mechanically-worked mineral ore mining operation. The mineral ore bed is isolated from the mechanically-worked mineral ore mining operation by passage of the drilled borehole through an impermeable layer adjacent to the mineral ore bed to be solution mined. The mineral ore bed is then solution-mined using a mining solvent introduced into the mineral ore bed to solubilize the mineral and form a mining solution, and the resulting mining solution is withdrawn from the mineral ore bed.

Abstract: The present invention is directed to a process of treating fly ash and/or fly ash leachate to immobilize heavy metals contained in such fly ash and/or fly ash leachate, which process comprises treating such fly ash and/or fly ash leachate with a soluble ferrous compound under alkaline conditions. This process may be conducted in the absence of any pH modification, mixing (in the sense of a physical blending with a solid material), drying or heating steps, making it practical for treatment of alkaline fly ash (and other coal combustion by-products) which is currently stored in landfills or wet ash lagoons, particularly fly ash which has been recovered from flue gas streams treated with highly alkaline materials such as trona, bicarbonate or limestone and the like.

Abstract: A method for removing sulfide from an aqueous alkali solution in which hydrogen peroxide is introduced into a sulfide-containing aqueous alkali solution associated with an alkali mineral recovery operation. The method is particularly useful for the processing of sulfide-containing aqueous alkali solutions containing NaHCO3 and Na2CO3, where bicarbonate in the sulfide-depleted alkali solution is decomposed to form Na2CO3, with concurrent evolution of gaseous carbon dioxide byproduct but without formation of gaseous H2S as a pollutant, and where Na2CO3 values are subsequently recovered from the sulfide-depleted carbonate-rich alkali solution via a crystallization operation.

Abstract: A method for removing sulfide from an aqueous alkali solution in which hydrogen peroxide is introduced into a sulfide-containing aqueous alkali solution associated with an alkali mineral recovery operation. The method is particularly useful for the processing of sulfide-containing aqueous alkali solutions containing NaHCO3 and Na2CO3, where bicarbonate in the sulfide-depleted alkali solution is decomposed to form Na2CO3, with concurrent evolution of gaseous carbon dioxide byproduct but without formation of gaseous H2S as a pollutant, and where Na2CO3 values are subsequently recovered from the sulfide-depleted carbonate-rich alkali solution via a crystallization operation.

Abstract: A method of treating lignocellulosic pulp in which an aqueous pulp mixture is treated with a bleaching agent and then subjected to an alkaline extraction at a reduced pH with a combination of alkaline agents comprising caustic soda and soda ash and using caustic soda for pH control.

Abstract: A process for recovering sodium carbonate decahydrate crystals from solutions and mother liquors supersaturated in sodium bicarbonate concentration. Feed liquors containing higher levels of sodium bicarbonate than traditionally fed to a sodium carbonate decahydrate crystallizer are used to create a mother liquor within a sodium carbonate decahydrate crystallizer that is supersaturated with respect to sodium bicarbonate. Substantially pure sodium carbonate decahydrate crystals may be precipitated from the supersaturated mother liquor without substantially precipitation of sodium bicarbonate containing crystals.

Abstract: A method for producing high grade soda ash from a solution mined brine containing sodium bicarbonate by processing the mine brine through a monohydrate crystallization step to the final product is described. The mine brine is treated to decompose and thereby convert sodium bicarbonate to sodium carbonate and to concentrate the sodium carbonate to a concentration such that a feed liquor is formed which is suitable for crystallizing sodium carbonate monohydrate crystals of high purity from the feed liquor. The sodium carbonate monohydrate crystals recovered from the process are converted to soda ash by known techniques.

Abstract: A method for converting sodium bicarbonate in a sodium carbonate monohydrate crystallization process to maintain a mother liquor composition in a sodium carbonate monohydrate crystallizer below the invariant point for the crystallizer for reducing or eliminating the cocrystallization of sodium sesquicarbonate crystals in the process. The mother liquor composition may be maintained below the invariant point by stripping carbon dioxide from a feed solution or from mother liquor recycled to the crystallizer.

Abstract: The formation of scale on equipment surface in contact with sodium alkali containing brines is inhibited by the addition of an alkylbenzene sulfonic acid or salt thereof to the brines.

Abstract: A process is disclosed for converting dilute brines of sodium carbonate and sodium bicarbonate to form feed solutions from which sodium based chemicals may be recovered. The sodium bicarbonate in a dilute brine is neutralized and the brine then fortified with calcined trona to form a feed liquor concentrated in sodium carbonate from which sodium based chemicals may be recovered in a Monohydrate or other crystallization process.

Abstract: A process for the production of soda ash by withdrawing an aqueous mining solution containing dissolved sodium carbonate and at least about 1 wt % sodium bicarbonate from an underground alkali source; stripping CO2 gas from the withdrawn aqueous mining solution, to convert sodium bicarbonate dissolved therein to sodium carbonate; co-crystallizing sodium carbonate monohydrate and sodium sesquicarbonate by evaporation of water from the CO2-stripped aqueous mining solution, without co-crystallization of anhydrous sodium carbonate, to form a slurry of crystalline solids in an aqueous liquor; recovering crystalline solids from the slurry; and calcining the recovered crystalline solids to produce soda ash.