Enhanced carbonation and carbon sequestration in cementitious binders

Abstract

A manufacturing process of a cement product includes: (a) reacting at least one anhydrous or hydrated cement component with liquid or supercritical CO2 to form a cement composition; and (b) curing the cement composition to form a cement product.

1 - 21 . (canceled) 
     
     
         22 . A manufacturing process of a cement-based product, comprising:
 (a) providing a monolithic structural element that comprises at least one cement component that includes portlandite (Ca(OH) 2 ) with aggregates, and that has been formed into a monolithic structural element;   (b) disposing the monolithic structural element in a reactor;   (c) exposing the monolithic structural element in the reactor to gaseous CO 2  to form a cement-based product,   wherein the exposing in (c) includes converting portlandite to calcium carbonate, and   wherein a partial pressure (concentration) of the CO 2  present in the reactor is higher than a partial pressure of CO 2  in ambient atmosphere.   
     
     
         23 . The manufacturing process of  claim 22 , wherein the at least one cement component (feedstock) further includes calcium silicate hydrate or a limestone. 
     
     
         24 . The manufacturing process of  claim 22 , wherein the at least one cement component further includes ordinary portland cement, a calcium sulfoaluminate cement, or a calcium aluminate cement. 
     
     
         25 . The manufacturing process of  claim 22 , wherein the at least one cement component further includes magnesium hydroxide, magnesium carbonate, or magnesium silicate. 
     
     
         26 . The manufacturing process of  claim 22 , wherein the exposing in (c) is carried out at a temperature in a range of about 5° C. to about 80° C. 
     
     
         27 . The manufacturing process of  claim 22 , wherein the exposing in (c) includes converting the at least one cement component to calcium carbonate or magnesium carbonate. 
     
     
         28 . The manufacturing process of  claim 27 , wherein a mass basis percentage of the at least one cement component converted to calcium carbonate or magnesium carbonate is at least 10% within a reaction residence time period of 6 h. 
     
     
         29 . A method of manufacturing a cement composition, comprising:
 (a) disposing a reactant in a reactor, wherein the reactant is in a monolithic form and comprises portlandite, aggregates and water;   (b) introducing CO 2  into the reactor; and   (c) exposing the reactant to gaseous CO 2  for a reaction time period to form calcium carbonate,   wherein a partial pressure of the CO 2  present in the reactor is higher than a partial pressure of CO 2  in ambient atmosphere.   
     
     
         30 . The method of  claim 29 , wherein the water content of the reactant mixture is no greater than 25% by mass. 
     
     
         31 . The method of  claim 29 , wherein a mass basis percentage of the reactant converted to calcium carbonate is at least 10% within the reaction time period of 6 h. 
     
     
         32 . The method of  claim 22 , wherein the shaping in (b) includes forming pores to facilitate permeation of CO 2  in the structural element. 
     
     
         33 . The method of  claim 22 , further comprising disposing the structural element in an atmosphere with a relative humidity greater than 8%, and less than 75%, prior to the exposing in (d). 
     
     
         34 . The method of  claim 22 , wherein the exposing the monolithic structural element in the reactor to CO 2  in step (d) results in an accelerated carbonation rate relative to exposing the monolithic structural element in the reactor to ambient atmospheric air. 
     
     
         35 . The method of  claim 29 , wherein the exposing the monolithic structural element in the reactor to CO 2  in step (d) results in an accelerated carbonation rate relative to exposing the monolithic structural element in the reactor to ambient atmospheric air. 
     
     
         36 . The method of  claim 22 , further comprising exposing the structural element in an atmosphere with a relative humidity of about 30% or greater prior to the exposing in (d). 
     
     
         37 . The method of  claim 22 , wherein the resulting cement composition includes an amount of calcium carbonate that is at least about 15% by mass. 
     
     
         38 . The method of  claim 22 , wherein the method includes reactant comprises multiple monolithic forms, each comprising portlandite, aggregates and water.