The present invention relates a mechanochemically carbonated clay. The invention further relates to methods of its production and uses thereof. The invention further relates to compositions comprising the mechanochemically carbonated clay and a further material selected from the group consisting of asphalt, cement, polymers and combinations thereof. The invention further relates to concrete and methods of their preparation.

The invention comprises a method of sequestering carbon dioxide. The method comprises delivering hyaloclastite, a volcanic glass or pumice to a mill capable of reducing the particle size of the hyaloclastite, a volcanic glass or pumice; processing the hyaloclastite, a volcanic glass or pumice in the mill so that the processed hyaloclastite, a volcanic glass or pumice has a volume-based mean particle size of less than or equal to 40 m; and exposing the hyaloclastite, a volcanic glass or pumice to carbon dioxide in gaseous, liquid or solid form during or after the particle reduction process.

The invention comprises a method of sequestering carbon dioxide. The method comprises delivering hyaloclastite, a volcanic glass or pumice to a mill capable of reducing the particle size of the hyaloclastite, a volcanic glass or pumice; processing the hyaloclastite, a volcanic glass or pumice in the mill so that the processed hyaloclastite, a volcanic glass or pumice has a volume-based mean particle size of less than or equal to 40 m; and exposing the hyaloclastite, a volcanic glass or pumice to carbon dioxide in gaseous, liquid or solid form during or after the particle reduction process.

A system and method are disclosed for the continuous carbonation of granular concrete under an atmosphere enriched in carbon dioxide. A sealed carbonation chamber cooperates with continuous inflow and outflow valve assemblies to maintain the enriched atmosphere while allowing uninterrupted material transfer. A conveyance mechanismsuch as an auger conveyor or helical flights on a rotating chamber walladvances the granular concrete and promotes exposure to carbon dioxide. Optional features include rotary seals at both inflow and outflow, a carbon dioxide recapture subsystem, and electronic process controls. In certain embodiments the granular concrete exhibits a defined particle size distribution to improve packing and sealing at the valve assemblies. The enriched atmosphere may be derived from an exhaust process. The invention enables industrially scalable processing that improves material properties while permanently mineralizing carbon dioxide.

The present disclosure relates to shaped cementitious compositions that comprise a substrate for aquatic flora and/or fauna attachment; methods for providing a substrate for aquatic flora and/or fauna attachment comprising depositing a shaped cementitious composition into a body of water; and methods for making a shaped cementitious composition. The shaped cementitious composition is formed from a pourable cementitious mixture comprising: (a) a pozzolan comprising a natural pozzolan and/or a manmade pozzolan; (b) MgO and/or Mg(OH).sub.2; (c) an aqueous solution comprising one or more accelerants; and (d) at least one aggregate. In some cases, the MgO and/or Mg(OH).sub.2 of (b) is included in the aqueous solution of (c). And, in various cases, the manmade pozzolan comprises a slag.