The present application pertains to methods for making metal oxides and/or citric acid and/or capturing carbon dioxide. In one embodiment, the application pertains to a process for producing calcium oxide, magnesium oxide, or both from a material comprising calcium and magnesium. The process may include reacting a material comprising calcium carbonate and magnesium carbonate. Separating, concentrating, and calcining may lead to the production of oxides such as calcium oxide or magnesium oxide. In other embodiments the application pertains to methods for producing an alkaline-earth oxide and a carboxylic acid from an alkaline earth cation-carboxylic acid anion salt. Such processes may include, for example, reacting an alkaline-earth cation-carboxylic acid anion salt with aqueous sulfur dioxide to produce aqueous alkaline-earth sulfite or bisulfite and an aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

A method of making building materials from an aqueous solution includes receiving the aqueous solution with dissolved ions and increasing a pH of the aqueous solution so the dissolved ions precipitate from the aqueous solution as salt. The method also includes collecting the salt precipitated from the aqueous solution and forming the building materials from the salt.

A production line and process including a moving carrier web for transporting the panel, and a device for controlling thickness of a formed, but not yet set, fiber reinforced cementitious panel slurry on the web. The thickness control device may include an angled rigid plate for contacting a downstream end of the angled plate with the slurry on the moving carrier web and a mounting stand for mounting the angled rigid. The thickness control device may include a flat horizontal plate at a fixed height over the moving carrier for contacting the entire lower surface of the horizontal plate with a facer on the slurry on the moving carrier web. Or, the thickness control device may include the angled plate and include the horizontal plate that contacts the facer.

A production line and process including a moving carrier web for transporting the panel, and a device for controlling thickness of a formed, but not yet set, fiber reinforced cementitious panel slurry on the web. The thickness control device may include an angled rigid plate for contacting a downstream end of the angled plate with the slurry on the moving carrier web and a mounting stand for mounting the angled rigid. The thickness control device may include a flat horizontal plate at a fixed height over the moving carrier for contacting the entire lower surface of the horizontal plate with a facer on the slurry on the moving carrier web. Or, the thickness control device may include the angled plate and include the horizontal plate that contacts the facer.

A method and composition are provided for backfilling the annular gap created as a tunnel boring machine advances through the ground. The fill material is comprised of two components that are combined and mixed together just prior to entering the annular gap. The first component is non-cement slurry consisting of a fluidized bed combustion ash such as coal ash. The second component consists of an alkali silicate such as sodium silicate. Additionally, ordinary Portland cement and/or metakaolin can be added to the grout composition.

A method and composition are provided for backfilling the annular gap created as a tunnel boring machine advances through the ground. The fill material is comprised of two components that are combined and mixed together just prior to entering the annular gap. The first component is non-cement slurry consisting of a fluidized bed combustion ash such as coal ash. The second component consists of an alkali silicate such as sodium silicate. Additionally, ordinary Portland cement and/or metakaolin can be added to the grout composition.

A method and composition are provided for backfilling the annular gap created as a tunnel boring machine advances through the ground. The fill material is comprised of two components that are combined and mixed together just prior to entering the annular gap. The first component is non-cement slurry consisting of a fluidized bed combustion ash such as coal ash. The second component consists of an alkali silicate such as sodium silicate. Additionally, ordinary Portland cement and/or metakaolin can be added to the grout composition.

Provided herein are compositions, methods, and systems related to bimodal, trimodal, and/or multi-modal distribution of reactive vaterite cement particles.

A fluidizing composition in the form of a liquid or in the form of a powder including at least one superplasticizer chosen from polycarboxylate ethers, characterized in that it includes from 1 to 20 parts by weight of at least one aromatic hydrocarbon sulfonic acid or one of its salts chosen from alkali salts, alkaline-earth salts or one of their mixtures, for 100 parts by weight of the superplasticizer. A method for preparing such fluidizing composition, a dry mortar incorporating the fluidizing composition, as well as plasters prepared from the dry mortar are also described.

A fluidizing composition in the form of a liquid or in the form of a powder including at least one superplasticizer chosen from polycarboxylate ethers, characterized in that it includes from 1 to 20 parts by weight of at least one aromatic hydrocarbon sulfonic acid or one of its salts chosen from alkali salts, alkaline-earth salts or one of their mixtures, for 100 parts by weight of the superplasticizer. A method for preparing such fluidizing composition, a dry mortar incorporating the fluidizing composition, as well as plasters prepared from the dry mortar are also described.