A method of preparing a cement hydration product nano-thin film, the method including: (1) preparing a cement hydration product; (2) preparing a water sacrificial layer film; (3) depositing the cement hydration product obtained in (1) on the surface of the water sacrificial layer film obtained in (2) to obtain a cement hydration product film; and (4) immersing the cement hydration product film in a saturated aqueous solution of calcium hydroxide to dissolve the water sacrificial layer film to obtain a nano-thin film of the cement hydration product.

Provided herein are compositions, methods, and systems comprising vaterite and magnesium oxide.

Provided herein are compositions, methods, and systems comprising vaterite and magnesium oxide.

Process for reducing hexavalent chromium in oxidic solids, which comprises the steps: a) mixing of the oxidic solid containing Cr(VI) with a carbon-containing compound which is liquid in the range from 20 to 100° C., b) treatment of the mixture obtained after a) in an indirectly heated reactor at a temperature of from 700° C. to 1100° C., particularly preferably at a temperature of from 800° C. to 1000° C., under a protective atmosphere, c) cooling of the reaction product obtained after b) to at least 300° C., preferably at least 150° C., under a protective atmosphere.

Process for reducing hexavalent chromium in oxidic solids, which comprises the steps: a) mixing of the oxidic solid containing Cr(VI) with a carbon-containing compound which is liquid in the range from 20 to 100° C., b) treatment of the mixture obtained after a) in an indirectly heated reactor at a temperature of from 700° C. to 1100° C., particularly preferably at a temperature of from 800° C. to 1000° C., under a protective atmosphere, c) cooling of the reaction product obtained after b) to at least 300° C., preferably at least 150° C., under a protective atmosphere.

Provided herein are systems for carbonation curing and CO.sub.2 mineralization of concrete composites and methods of manufacturing a carbonated concrete composite. A method of manufacturing a carbonated concrete composites includes contacting concrete with CO.sub.2-containing gas streams in the carbonation reactor having a gas stream inlet and an outlet to provide optimal gas flow distribution and gas velocity. The concrete precursor includes a binder, one or more aggregates, and water. A gas stream is received at the carbonation reactor. The gas stream includes carbon dioxide. The concrete precursor is maintained at a suitable temperature in the carbonation reactor to thereby react the concrete precursor with the gas stream to produce carbonate minerals in the carbonated concrete composite.

A variety of methods and compositions are disclosed, including, in one embodiment, a settable composition comprising: water; and a cementitious component having a calculated reactive index.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods make use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents may be combined with Portland cement and an alkali activator to form a blended cement. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

Carbon-sequestering composite mixture and methods of carbon sequestration utilizing an aquatic composite structure composed of the composite mixture. The mixture comprises a composite, nanoparticles, and binder. The nanoparticles impact the pore size of the composite mixture, thereby positively impacting the carbon sequestration properties of the mixture. By emplacing an aquatic composite structure composed of such a mixture in an aquatic environment such that it provides erosion mitigation, simultaneous environmental protection effects may be achieved. Further, the binder positively encourages natural ecological growth on the aquatic composite structure, thereby encouraging environmental restoration and encouraging naturally-occurring carbon sequestration from the ecological growth, potentially well past the point at which the aquatic composite structure is unable to continue to sequester carbon.

Carbon-sequestering composite mixture and methods of carbon sequestration utilizing an aquatic composite structure composed of the composite mixture. The mixture comprises a composite, nanoparticles, and binder. The nanoparticles impact the pore size of the composite mixture, thereby positively impacting the carbon sequestration properties of the mixture. By emplacing an aquatic composite structure composed of such a mixture in an aquatic environment such that it provides erosion mitigation, simultaneous environmental protection effects may be achieved. Further, the binder positively encourages natural ecological growth on the aquatic composite structure, thereby encouraging environmental restoration and encouraging naturally-occurring carbon sequestration from the ecological growth, potentially well past the point at which the aquatic composite structure is unable to continue to sequester carbon.