The procedures for obtaining calcium oxide from eggshells with applications in food processes, refers to the plurality of procedures for obtaining Calcium Oxide (XAM), from eggshells, is based on a circular economy, in which waste eggshells are collected from different food establishments and agglomerated in the production center. The application of high temperatures (>900° C.) to the crushed eggshells, provides the transformation of calcium carbonate (CaCO3) into calcium oxide (CaO) with a pH that exceeds 12. The use of XAM as a raw material with the aforementioned characteristics, constitutes the ideal component to alkalinize different preparations in the production of different foods and particularly in the nixtamalization procedures for the production of corn dough prior to the production of tortillas, tamales, and other varieties of food.

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.

Techniques for converting carbonate material to carbon monoxide include transferring heat and at least one feed stream that includes a carbonate material and at least one of hydrogen, oxygen, water, or a hydrocarbon, into an integrated calcination and syngas production system that includes a syngas generating calciner (SGC) reactor; calcining the carbonate material to produce a carbon dioxide product and a solid oxide product; initiating a syngas production reaction; producing, from the syngas production reaction, at least one syngas product that includes at least one of a carbon monoxide product, a water product or a hydrogen product; and transferring at least one of the solid oxide product or the at least one syngas product out of the SGC reactor.

Techniques for converting carbonate material to carbon monoxide include transferring heat and at least one feed stream that includes a carbonate material and at least one of hydrogen, oxygen, water, or a hydrocarbon, into an integrated calcination and syngas production system that includes a syngas generating calciner (SGC) reactor; calcining the carbonate material to produce a carbon dioxide product and a solid oxide product; initiating a syngas production reaction; producing, from the syngas production reaction, at least one syngas product that includes at least one of a carbon monoxide product, a water product or a hydrogen product; and transferring at least one of the solid oxide product or the at least one syngas product out of the SGC reactor.

There is provided herein a process for producing metal oxide in a flash calciner, the process comprising: a. pre-heating a metal carbonate particulate stream, prior to the particulate stream being fed into the flash calciner; and, b. calcining the particulate stream in a flash calciner to produce a raw stream comprising metal oxide and a flue gas comprising CO.sub.2,
wherein at least a portion of the flue gas comprising CO.sub.2 produced in step (b) is used to pre-heat the metal carbonate particulate in step (a).

There is provided herein a process for producing metal oxide in a flash calciner, the process comprising: a. pre-heating a metal carbonate particulate stream, prior to the particulate stream being fed into the flash calciner; and, b. calcining the particulate stream in a flash calciner to produce a raw stream comprising metal oxide and a flue gas comprising CO.sub.2,
wherein at least a portion of the flue gas comprising CO.sub.2 produced in step (b) is used to pre-heat the metal carbonate particulate in step (a).

Systems and methods for impurity removal to limestone using modifications to the typical calcination process of turning calcium carbonate into calcium oxide prior to slaking to produce calcium hydroxide. 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 prior to slaking to produce calcium hydroxide. 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 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.

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.