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

The present application pertains to methods for making alkali hydroxide, or alkali carbonates, or alkali bicarbonates, or alkaline—earth sulfates. In one embodiment, a material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with an alkali sulfate to form an alkaline earth sulfate and alkali sulfite or bisulfite. The alkali sulfite or bisulfite is converted into an alkali hydroxide, or an alkali carbonate, or an alkali bicarbonate. In another embodiment, ammonium carbonate or ammonium bicarbonate is reacted with an alkali sulfate, to form ammonium sulfate and an alkali carbonate or alkali bicarbonate. A material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with the ammonium sulfate to form an alkaline earth sulfate and ammonium sulfite or ammonium bisulfite. The ammonium sulfite or bisulfite is regenerated into ammonia, or ammonium hydroxide, or ammonium carbonate, or ammonium bicarbonate.

A process includes converting hydrocarbons to at least one molecular energy carrier and carbon dioxide, reacting said carbon dioxide with a divalent metal-containing silicate to form solid divalent metal carbonate and silicate and utilizing at least one of said carbonate and silicate in the production of construction and/or chemical material.

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 bisulfate and an aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

The present application pertains to methods for making metal oxides and/or citric acid. 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-bisulfite and aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

The present application pertains to methods for making alkali hydroxide, or alkali carbonates, or alkali bicarbonates, or alkaline—earth sulfates. In one embodiment, a material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with an alkali sulfate to form an alkaline earth sulfate and alkali sulfite or bisulfite. The alkali sulfite or bisulfite is converted into an alkali hydroxide, or an alkali carbonate, or an alkali bicarbonate. In another embodiment, ammonium carbonate or ammonium bicarbonate is reacted with an alkali sulfate, to form ammonium sulfate and an alkali carbonate or alkali bicarbonate. A material comprising an alkaline earth is converted to an alkaline earth sulfite or bisulfite and reacted with the ammonium sulfate to form an alkaline earth sulfate and ammonium sulfite or ammonium bisulfite. The ammonium sulfite or bisulfite is regenerated into ammonia, or ammonium hydroxide, or ammonium carbonate, or ammonium bicarbonate.

The present application pertains to methods for making metal oxides and/or citric acid. 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—bisulfite and aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

An illustrative method for CO2 sequestration may include the step of sequestering at least a portion of a CO2 gas emitted during operation of the ready-mix concrete production system in (i) a ready-mix concrete produced by the read-mix concrete production system, and/or (ii) calcium carbonate formed by processing water used during operation of the ready-mix concrete production and delivery system.

The present invention pertains to a process for producing captured carbon dioxide. Calcium carbonate may be reacted with sulfur dioxide to produce calcium sulfite and gaseous carbon dioxide. Calcium sulfite may be thermally decomposed to produce gaseous sulfur dioxide. The processes may be used in conjunction with combusting various fuels such as a carbonaceous fuel, or a sulfurous fuel, or a nitrogenous fuel, or a hydrogen fuel, or a combination thereof.

The present application pertains to methods for making metal oxides and/or citric acid. 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-bisulfite and aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.