Electrochemical system, apparatus and method to generate metal hydroxide in the presence of metal silicates

A method of generating hydrogen, an oxidative gas and a metal hydroxide for sequestering gaseous carbon dioxide or other acid gases, the method comprising the steps of:

• (a) supplying a direct current from an electrical source at a predetermined voltage to an electrolytic container having an anode, a cathode, an electrolyte solution comprising a metal salt, an anode region adapted to generate the oxidative gas and an acidic solution, and a cathode region adapted to generate hydrogen gas and a dissolved metal hydroxide solution, the metal in said dissolved metal hydroxide solution being derived from the electrolyte solution;
• (b) supplying, from a source disposed externally to the electrolytic container, a metal silicate soluble in the acidic solution;
• (c) removing the acidic solution from the anode region to another container outside the electrolytic container, for reacting the removed acidic solution with the metal silicate to generate a metal salt solution, wherein the metal is derived from the metal silicate;
• (d) reacting the metal salt solution from the step (c) with the dissolved metal hydroxide solution of the step (a) to produce a reaction solution and generate another metal hydroxide, wherein the metal in said another metal hydroxide is derived from the metal silicate;
• (e) separating said another metal hydroxide from the remaining reaction solution in the step (d);
• and
• (f) supplying the remaining reaction solution back to the electrolytic container for use as the electrolyte solution.

An apparatus for electrochemically generating metal hydroxide, oxygen and hydrogen, the apparatus comprising:

• an electrolytic container having an anode, a cathode, a direct current source connected to the anode and the cathode, an electrolyte solution disposed in said electrolytic container to undergo electrolysis when the direct current is applied, two ion-exchange membranes disposed in said electrolytic container between said anode and said cathode and defining a cathode region, an anode region and a central region between said anode region and said cathode region;
• a second container disposed externally to said electrolytic container for holding a quantity of a solid metal silicate material, the second container being in fluid communication with said electrolytic container;
• means for supplying acidic solution from the anode region to said second container to effect dissolution of said solid mineral silicate material and to generate a metal salt solution wherein the metal is derived from said solid metal silicate material;
• purification means configured to purify said metal salt solution;
• a hydroxide reactor in fluid communication with said electrolytic container, for precipitating low-solubility metal hydroxides whose metal is derived from the dissolution of the solid metal silicate material;
• and
• a filtering unit connected to the hydroxide reactor and configured for separating the low-solubility precipitate from a solution removed from the hydroxide reactor.