A method includes: (1) using a chelating agent, extracting divalent ions from a brine solution as complexes of the chelating agent and the divalent ions; (2) using a weak acid, regenerating the chelating agent and producing a divalent ion salt solution; and (3) introducing carbon dioxide to the divalent ion salt solution to induce precipitation of the divalent ions as a carbonate salt. Another method includes: (1) combining water with carbon dioxide to produce a carbon dioxide solution; (2) introducing an ion exchanger to the carbon dioxide solution to induce exchange of alkali metal cations included in the ion exchanger with protons included in the carbon dioxide solution and to produce a bicarbonate salt solution of the alkali metal cations; and (3) introducing a brine solution to the bicarbonate salt solution to induce precipitation of divalent ions from the brine solution as a carbonate salt.

A method includes: (1) using a chelating agent, extracting divalent ions from a brine solution as complexes of the chelating agent and the divalent ions; (2) using a weak acid, regenerating the chelating agent and producing a divalent ion salt solution; and (3) introducing carbon dioxide to the divalent ion salt solution to induce precipitation of the divalent ions as a carbonate salt. Another method includes: (1) combining water with carbon dioxide to produce a carbon dioxide solution; (2) introducing an ion exchanger to the carbon dioxide solution to induce exchange of alkali metal cations included in the ion exchanger with protons included in the carbon dioxide solution and to produce a bicarbonate salt solution of the alkali metal cations; and (3) introducing a brine solution to the bicarbonate salt solution to induce precipitation of divalent ions from the brine solution as a carbonate salt.

The present specification discloses a method of producing a concentrated carbonate aqueous solution. The present invention relates to a method for producing a concentrated carbonate aqueous solution, comprising a step of dewatering a hydrogen carbonate aqueous solution by means of a salt blocking membrane to prepare a concentrated hydrogen carbonate aqueous solution, wherein the concentrated hydrogen carbonate aqueous solution obtained in the above step is heated to thermally decompose the hydrogen carbonate into carbonate, carbon dioxide and water, and to evaporate water to obtain a concentrate of the carbonate aqueous solution.

The present specification discloses a method of producing a concentrated carbonate aqueous solution. The present invention relates to a method for producing a concentrated carbonate aqueous solution, comprising a step of dewatering a hydrogen carbonate aqueous solution by means of a salt blocking membrane to prepare a concentrated hydrogen carbonate aqueous solution, wherein the concentrated hydrogen carbonate aqueous solution obtained in the above step is heated to thermally decompose the hydrogen carbonate into carbonate, carbon dioxide and water, and to evaporate water to obtain a concentrate of the carbonate aqueous solution.

A method for producing a concentrated aqueous sodium hydroxide solution from a purge stream deriving from a sodium carbonate, or sesquicarbonate, or wegsheiderite crystallizer, or sodium bicarbonate crystallizer, said purge stream comprising sodium carbonate and/or bicarbonate, and at least 1% of sodium chloride or sodium sulfate and a soluble impurity from an ore deposit comprising at least one of the following elements: As, Ba, B, Ca, Co, K, Li, Mo, P, Pb, Se, Sn, Sr, Te, Tl, Ti, V, and W, to be purified, the method comprising: causticizing at least 50 mol. % of the sodium carbonate into a caustic solution and into a calcium carbonate mud with lime and water; separating the mud from the caustic solution; concentrating the caustic solution by removing part of the water to obtain a concentrated caustic solution comprising at least 25% NaOH, and a crystallized solid comprising sodium carbonate and sodium chloride and/or sulfate; and separating the crystallized solid from the concentrated caustic solution, said crystallized solid to be disposed of or to be further valorized.

A soda ash and sodium bicarbonate production method is provided, in which solution mining, pretreatment, stripping, concentration, sodium carbonate decahydrate crystallization, separation, dissolution, sodium carbonate monohydrate crystallization, separation and drying are performed to obtain dense soda ash. A dissolved sodium carbonate decahydrate solution or a concentrated brine 3 is subjected to crystallization, separation and drying to produce sodium bicarbonate. A discharge liquid 1 generated in the sodium carbonate decahydrate crystallization and separation is subjected to causticization and evaporation to recycle sodium carbonate. Causticized sludge generated in causticization is calcined and then recycled for causticization. The process provided herein maximizes the resource utilization.

Provided is a method of producing a porous molded body, the method including: the step of obtaining a molded body by molding a raw material that contains from 1 part by mass to 100 parts by mass of a bicarbonate compound (A) represented by AHCO.sub.3 (wherein, A represents Na or K) and from 0 parts by mass to 99 parts by mass of a compound (B) represented by B.sub.nX (wherein, B represents Na or K; X represents CO.sub.3, SO.sub.4, SiO.sub.3, F, Cl, or Br; and n represents an integer of 1 or 2 as determined by the valence of X) (provided that a total amount of (A) and (B) is 100 parts by mass); and the step of obtaining a porous molded body by performing a heat treatment of the molded body in a temperature range of from 100° C. to 500° C. and an atmosphere that contains water vapor in an amount of from 1.0 g/m.sup.3 to 750,000 g/m.sup.3 and thereby thermally decomposing not less than 90% by mass of the bicarbonate compound (A).

The present disclosure relates to a method for chemically modifying particles of a bicarbonate salt in a co-rotating twin-screw extruder and chemically modified bicarbonate particles prepared therefrom. The present disclosure also relates to a method for controlling an amount of carbonate salt formed during chemical modification of bicarbonate salt particles.

The present disclosure relates to a method for chemically modifying particles of a bicarbonate salt in a co-rotating twin-screw extruder and chemically modified bicarbonate particles prepared therefrom. The present disclosure also relates to a method for controlling an amount of carbonate salt formed during chemical modification of bicarbonate salt particles.

The disclosure provides seven integrated methods for the chemical sequestration of carbon dioxide (CO.sub.2), nitric oxide (NO), nitrogen dioxide (NO.sub.2) (collectively NO.sub.x, where x=1, 2) and sulfur dioxide (SO.sub.2) using closed loop technology. The methods recycle process reagents and mass balance consumable reagents that can be made using electrochemical separation of sodium chloride (NaCl) or potassium chloride (KCl). The technology applies to marine and terrestrial exhaust gas sources for CO.sub.2, NOx and SO.sub.2. The integrated technology combines compatible and green processes that capture and/or convert CO.sub.2, NOx and SO.sub.2 into compounds that enhance the environment, many with commercial value.