(57) Cement and concrete compositions are produced via metal hydroxides and metal oxides isolated from aqueous sources such as seawater or wastewater. Aqueous solutions are electrolyzed to produce an alkaline component stream having an elevated pH, which when mixed with mineralized seawater causes metal ions dissolved therein to precipitate out in the form of metal hydroxides such as Mg(OH), and Ca(OH)2. These metal hydroxide products are then utilized as feedstocks for production of cement and concrete structural elements, or are converted to metal oxides suitable for the same purpose. The hydroxide products are then subjected to pressure and prolonged exposure to carbon dioxide to accelerate carbonation of the hydrated product. The resulting carbonates exhibit sufficient compressive strength for use in making structural components for construction, while reducing or eliminating the carbon footprint associated with traditional methods of cement and concrete manufacturing. Excess demineralized alkaline component can be recycled for additional electrolysis, or returned to a neutral pH for use in water desalination processes or even returned to the environment.
(71) Shiho Kawashima, Brooklyn, NY (US); Daniel V. Esposito, New York, NY (US); Siwei Ma, San Jose, CA (US); Abdullah Huzeyfe Akca, New York, NY (US)
(73) The Trustees of Columbia University in the City of New York, New York, NY (US)