A system for making oxide material may comprise a preheating cyclone stage for receiving a solid carbonate material and operating at a temperature less than a calcination temperature of the solid carbonate material, a calcination cyclone stage for heating the preheated solid carbonate material and operating at a temperature of at least the calcination temperature to convert the preheated solid carbonate material to a solid oxide material and carbon dioxide gas, a cooling cyclone stage for cooling the solid oxide material and operating at a temperature less than the calcination temperature to cool the solid oxide material to ambient temperature, a first recirculating system to extract and recirculate a first gas from an outlet of the calcination cyclone stage to an inlet of the calcination cyclone stage zone, and a second recirculating system to extract and recirculate a second gas from the cooling cyclone stage to the preheating cyclone stage.

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.

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.

Systems and methods for impurity removal to limestone using modifications to the typical calcination process of turning calcium carbonate into calcium oxide. Specifically, substantially increasing the temperature to 1100° C. or higher and increasing soak time can result in reductions in certain undesirable impurities, particularly with regards to lead and lead compounds.

Systems and methods for impurity removal to limestone using modifications to the typical calcination process of turning calcium carbonate into calcium oxide. Specifically, substantially increasing the temperature to 1100° C. or higher and increasing soak time can result in reductions in certain undesirable impurities, particularly with regards to lead and lead compounds.

A system for reducing carbon dioxide emissions from a flue gas generated via combusting a fossil fuel is provided. The system includes a calcination chamber and a sealing-purger. The calcination chamber is configured to receive a plurality of loaded sorbent particles and a plurality of heat-transferring particles such that the loaded sorbent particles are heated within the calcination chamber so as to release carbon dioxide. The sealing-purger includes at least one gravity driven moving particle bed. The at least one gravity driven moving particle bed allows the plurality of heat-transferring particles or the plurality of sorbent particles to enter or leave the calcination chamber while restricting the flue gas from entering the calcination chamber and the released carbon dioxide particles from leaving the calcination chamber.

A system for reducing carbon dioxide emissions from a flue gas generated via combusting a fossil fuel is provided. The system includes a calcination chamber and a sealing-purger. The calcination chamber is configured to receive a plurality of loaded sorbent particles and a plurality of heat-transferring particles such that the loaded sorbent particles are heated within the calcination chamber so as to release carbon dioxide. The sealing-purger includes at least one gravity driven moving particle bed. The at least one gravity driven moving particle bed allows the plurality of heat-transferring particles or the plurality of sorbent particles to enter or leave the calcination chamber while restricting the flue gas from entering the calcination chamber and the released carbon dioxide particles from leaving the calcination chamber.

This invention is about calcium oxide. The invention relates more particularly to obtaining the calcium oxide with high purity and on the implementation.

This invention is about calcium oxide. The invention relates more particularly to obtaining the calcium oxide with high purity and on the implementation.

Provided herein are zero carbon dioxide (CO.sub.2) emission processes and systems to carry out the processes, comprising a) calcining limestone in a cement plant in an electric kiln to form a mixture comprising calcium oxide and a first gaseous stream comprising clean carbon dioxide, wherein the clean carbon dioxide comprises no gaseous or non-gaseous components from combustion of fuel; b) treating the mixture comprising calcium oxide with a N-containing salt solution under one or more dissolution conditions to produce a first aqueous solution comprising calcium salt; and c) contacting the first aqueous solution with the first gaseous stream comprising clean carbon dioxide under one or more precipitation conditions to produce a precipitation material comprising vaterite, aragonite, calcite, or combinations thereof.