Solvay (societe Anonyme)

Francesco Posar

Edgard Nicolas

Alessandra Pastacaldi

Luc Botte

Mauro Ricciardi

Stefano Bigini

Process for the manufacture of alkali metal hydroxide, according to which an electrodialysis cell containing three compartments is used, an aqueous alkali metal halide solution is circulated in a saline compartment of the cell, delimited between an anionic membrane and a cationic membrane, an alkali metal halide is introduced into an acidic compartment of the cell, delimited between the anionic membrane and a cationic face of a bipolar membrane and an aqueous alkali metal hydroxide solution is extracted from an alkaline compartment of the cell, delimited between the cationic membrane and an anionic face of the bipolar membrane.

Process for the manufacture of alkali metal hydroxide

Process for manufacturing sodium hydroxide by the electrodialysis of sodium carbonate in an electrodialysis cell having three compartments, in which an aqueous sodium carbonate solution is introduced into a compartment of the cell which is bounded between two cationic membranes, an acid is introduced into a compartment which is bounded between one of the cationic membranes and a cationic face of a bipolar membrane, and an aqueous sodium hydroxide solution is removed from a compartment which is adjacent to an anionic face of the bipolar membrane.

Process for manufacturing an aqueous sodium hydroxide solution

Method for making a bipolar membrane

Electrode for an electrochemical process, comprising, on an electrically conductive substrate, a platinum, iridium oxide and tin oxide coating, the coating comprising more than 8% by weight of iridium oxide. Use of the said electrode as the anode in a process for electrolyzing an alkali metal salt in aqueous solution.

Electrode for an electrochemical process and use of the said electrode

Process for the manufacture of a bipolar membrane, according to which a cationic membrane is treated with a compound of a polyvalent metal and with an aqueous alkali metal hydroxide solution comprising lithium hydroxide and is then joined side by side to an anionic membrane. The bipolar membrane finds an application in the manufacture of aqueous sodium hydroxide solutions by electrodialysis. No figure.

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Rosignano Solvay, Italy

Francesco Posar