Solvay (societe Anonyme)

Solvay Sa

Francis M Coustry

Jean-Paul Detournay

Michel Hanse

Perrine Davoine

Kurt Allen

Alessandra Pastacaldi

Process for the joint production of sodium carbonate and sodium bicarbonate crystals, according to which: a solid powder derived from sodium sesquicarbonate, having a mean particle diameter comprised between 0.1 and 10 mm is dissolved in water; the resulting water solution is introduced into a crystallizer, wherein a first water suspension comprising sodium carbonate crystals is produced; the first water suspension is subjected to a separation, in order to produce crystals comprising sodium carbonate on the one hand, which are valorized, and a mother liquor on the other hand; and a part of the mother liquor is taken out of the crystallizer and put into contact in, a gas liquid contactor, with a gas comprising carbon dioxide, in order to produce a second water suspension comprising sodium bicarbonate crystals, which are separated and valorized. A reagent powder comprising sodium bicarbonate crystals made by such process.

Process for the joint production of sodium carbonate and sodium bicarbonate

In a process to produce sodium carbonate, a first production solution comprising sodium carbonate is introduced into less basic compartments of an electrodialyzer comprising alternating less basic and more basic adjacent compartments separated from each other by cationic membranes, the more basic compartments being delimited by anionic faces of bipolar membranes on one side and by the cationic membranes on the other side; a second production solution comprising sodium carbonate is introduced into the more basic compartments of the electrodialyzer; a solution comprising sodium hydroxide is produced into the more basic compartments by combination of sodium ions flux sodium ions crossing the cationic membrane and hydroxyl ions flux crossing the anionic face of the bipolar membranes, and is then extracted from the electrodialyzer to be used as a reaction solution; and the reaction solution is reacted with sodium bicarbonate in order to form a produced solution comprising sodium carbonate.

Process for producing sodium bicarbonate

Process for the joint production of sodium carbonate and sodium bicarbonate out of sesquicarbonate, in which the sesquicarbonate is dissolved in water, in order to form a feed water solution comprising both sodium carbonate and sodium bicarbonate, in which at least part of the feed water solution is introduced into all the compartments of an electrodialyser and in which a sodium bicarbonate enriched solution and a sodium carbonate enriched solution are extracted from the compartments.

Process for the production of sodium bicarbonate

A process for the joint production of sodium carbonate and sodium bicarbonate out of trona, comprising: introducing and dissolving crushed trona ore in a leaching tank containing a solution comprising sodium carbonate and sodium bicarbonate, saturated in sodium bicarbonate, in order to produce solid particles suspended in a production solution comprising sodium carbonate, the solid particles containing insoluble impurities and at least 65% in weight of sodium bicarbonate; separating the solid particles from the production solution containing sodium carbonate; drying and valorizing the separated solid particles; taking at least part of the production solution containing sodium carbonate out of the leaching tank in order to constitute a produced solution which is valorized; and introducing water in the leaching tank.

Process for producing sodium bicarbonate for purifying flue gases, according to which an aqueous solution containing sodium sulfate is subjected to electrodialysis to produce a sodium hydroxide solution and a sodium bisulfate solution, the sodium hydroxide solution being carbonated in order to obtain sodium bicarbonate.

Process for producing sodium bicarbonate for flue gas desulphurization

A method for producing sodium carbonate monohydrate, according to which an aqueous sodium chloride solution () is electrolyzed in a membrane-type cell () from which an aqueous sodium hydroxide solution () is collected, and carbonated by direct contact with carbon dioxide () to form a slurry of crystals of a sodium carbonate monohydrate (), and the slurry or its mother liquor is evaporated () to collect sodium carbonate monohydrate ().

Method for obtaining sodium carbonate monohydrate crystals

Method for producing sodium carbonate, according to which an aqueous sodium chloride solution () is electrolyzed in a membrane-type cell () from which an aqueous sodium hydroxide solution () is collected, and carbonated by direct contact with carbon dioxide () to form a slurry of crystals of a sodium carbonate (), and the slurry or its mother liquor is evaporated () to collect sodium carbonate ().

Method for obtaining sodium carbonate crystals

An aqueous solution of sodium chloride is electrolyzed in a cell () with an ion permselective membrane to produce, on the one hand, chlorine () which is converted in a chlorine production unit () and, on the other, an aqueous sodium hydroxide solution (), which is carbonated using a flue gas () from an electricity and steam cogeneration unit (), and the resulting carbonated solution () is evaporated to produce sodium carbonate crystals ().

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Alsemberg, Belgium

Francis M Coustry