A method of pumping a fluid and reactive solid into a mineral formation includes the fluid reacting with the mineral formation to produce a nucleation product. The method may be used in shale formations to seal fissures and prevent leakage. The fluid used in this method may comprise CO.sub.2 and the nucleation products may be the products of carbonation reactions. A cement formed by reacting CO.sub.2 with a reactive solid under deep geological formation conditions is also disclosed.

Provided herein are compositions and methods of carbonation processing for the fabrication of cementitious materials and concrete products. Embodiments include manufacturing processes of a low-carbon concrete product comprising: forming a cementitious slurry including portlandite; shaping the cementitious slurry into a structural component; and exposing the structural component to a CO.sub.2 waste stream, thereby enabling manufacture of the low-carbon concrete product.

Provided herein are compositions and methods of carbonation processing for the fabrication of cementitious materials and concrete products. Embodiments include manufacturing processes of a low-carbon concrete product comprising: forming a cementitious slurry including portlandite; shaping the cementitious slurry into a structural component; and exposing the structural component to a CO.sub.2 waste stream, thereby enabling manufacture of the low-carbon concrete product.

Disclosed is a CO.sub.2 solidified fiber cement board and its preparation method. The matrix composition of the fiber cement board prepared in this disclosure is calcium carbonate, which has high compactness, and the crystal form of calcium carbonate is adjusted by adding shell powder to improve the toughness of the matrix, so that the fiber cement board has excellent mechanics and durability performance. In addition, the preparation process does not require high temperature maintenance, and has the characteristics of normal temperature preparation, which creates conditions for the introduction of organic synthetic fibers, so that the organic synthetic fibers can further improve the brittleness of cement fiberboard. While reducing energy consumption, the preparation process can also effectively solve the problem that excessive pressure is easily generated in the fiberboard under high temperature conditions in the existing high-temperature and high-pressure curing process.

Disclosed is a CO.sub.2 solidified fiber cement board and its preparation method. The matrix composition of the fiber cement board prepared in this disclosure is calcium carbonate, which has high compactness, and the crystal form of calcium carbonate is adjusted by adding shell powder to improve the toughness of the matrix, so that the fiber cement board has excellent mechanics and durability performance. In addition, the preparation process does not require high temperature maintenance, and has the characteristics of normal temperature preparation, which creates conditions for the introduction of organic synthetic fibers, so that the organic synthetic fibers can further improve the brittleness of cement fiberboard. While reducing energy consumption, the preparation process can also effectively solve the problem that excessive pressure is easily generated in the fiberboard under high temperature conditions in the existing high-temperature and high-pressure curing process.

The invention provides novel apparatus and processes for gas flow and conditioning to achieve optimal CO.sub.2 curing of articles of composite materials (e.g., precast objects made of carbonatable calcium silicate-based cements), with solid interior or having hollow interior ducts, channels and chambers or otherwise being hollowed out, as well as the precast objects so made, which are suitable for a variety of applications in construction, pavements and landscaping, and infrastructure.

The invention provides novel apparatus and processes for gas flow and conditioning to achieve optimal CO.sub.2 curing of articles of composite materials (e.g., precast objects made of carbonatable calcium silicate-based cements), with solid interior or having hollow interior ducts, channels and chambers or otherwise being hollowed out, as well as the precast objects so made, which are suitable for a variety of applications in construction, pavements and landscaping, and infrastructure.

Compositions comprising highly reflective microcrystalline/amorphous materials are provided. In some instances, the highly reflective materials are microcrystalline or amorphous carbonate materials, which may include calcium and/or magnesium carbonate. In some instances, the materials are CO.sub.2 sequestering materials. Also provided are methods of making and using the compositions, e.g., to increase the albedo of a surface, to mitigate urban heat island effects, etc.

Compositions comprising highly reflective microcrystalline/amorphous materials are provided. In some instances, the highly reflective materials are microcrystalline or amorphous carbonate materials, which may include calcium and/or magnesium carbonate. In some instances, the materials are CO.sub.2 sequestering materials. Also provided are methods of making and using the compositions, e.g., to increase the albedo of a surface, to mitigate urban heat island effects, etc.

Compositions and methods for carbonation curing of cement and/or concrete are provided, where a lixiviant species that solubilizes calcium from oxides and silicates provided with the cement or concrete is included in the curing cement or concrete mixture. Reaction of solubilized calcium with carbon dioxide results in the formation of insoluble calcium carbonate that is incorporated into the structure of the cured cement or concrete, and simultaneously regenerates the lixiviant species. Rapid reaction of carbon dioxide within the curing cement or concrete further generates a concentration gradient that accelerates uptake of additional carbon dioxide, for example from ambient air. This incorporation of environmental carbon also causes the cured cement or concrete to be used for long term carbon sequestration.