A method for calcination includes providing a heated coarse solid particle stream with a carbon dioxide rich sorbent to a reactor having a rotatable container.

A process comprising the following steps: a) calcination of a metal carbonate by combustion of a fuel in the presence of a mixture of oxygen, water vapour and carbon dioxide, to generate a metal oxide, water vapour, carbon dioxide and heat; b) using the heat generated to drive an oxygen generation reaction; and c) use of the oxygen generated in step b) in calcination step a). The use of the process on carbon dioxide sequestration and/or in oxygen generation.

A process comprising the following steps: a) calcination of a metal carbonate by combustion of a fuel in the presence of a mixture of oxygen, water vapour and carbon dioxide, to generate a metal oxide, water vapour, carbon dioxide and heat; b) using the heat generated to drive an oxygen generation reaction; and c) use of the oxygen generated in step b) in calcination step a). The use of the process on carbon dioxide sequestration and/or in oxygen generation.

A method for calcination includes providing a heated coarse solid particle stream with a carbon dioxide rich sorbent to a reactor having a rotatable container.

A method for calcination includes providing a heated coarse solid particle stream with a carbon dioxide rich sorbent to a reactor having a rotatable container.

A recirculated-suspension pre-calciner system is disclosed, comprising: a vortex cyclone dust collecting equipment including a plurality of devices, wherein a top device of the vortex cyclone dust collecting equipment is used as a feed system; a vertical combustion kiln; a blower; and a powder purge system, wherein powders in the feed system fall into the vortex cyclone dust collecting equipment and pass through a plurality of the devices to mix and exchange heat with flue gas comprising CO.sub.2, generating calcination reaction and releasing CO2 into the flue gas. and the steam is separated and transported to the feed system by the blower and acts as a carrier gas of powders.

A recirculated-suspension pre-calciner system is disclosed, comprising: a vortex cyclone dust collecting equipment including a plurality of devices, wherein a top device of the vortex cyclone dust collecting equipment is used as a feed system; a vertical combustion kiln; a blower; and a powder purge system, wherein powders in the feed system fall into the vortex cyclone dust collecting equipment and pass through a plurality of the devices to mix and exchange heat with flue gas comprising CO.sub.2, generating calcination reaction and releasing CO2 into the flue gas. and the steam is separated and transported to the feed system by the blower and acts as a carrier gas of powders.

The disclosure features compositions that include a material featuring three calcium phosphate phases that form one or more integral units of a solid, where a first one of the three phases includes one or more regions formed of hydroxyapatite, a second one of the three phases includes one or more regions formed of -tricalcium phosphate, a third one of the three phases includes one or more regions formed of amorphous calcium phosphate, and where at least some of the regions corresponding to the first, second, and third phases contact one another in the one or more integral units of the solid.

The disclosure features methods that include obtaining a first calcium hydroxide solution that includes a first concentration of calcium ions and a second calcium hydroxide solution that includes a second concentration of calcium ions, adding a phosphoric acid solution to the first calcium hydroxide solution to generate a combined solution featuring an aqueous suspension of calcium dihydrogen phosphate particles, and adding the second calcium hydroxide solution to the combined solution to form a product solution that includes an aqueous suspension of particles of a calcium phosphate composition.

The disclosure features methods that include obtaining a first plurality of particles that include calcium carbonate, where the particles have a distribution of sizes between 8 mm and 12 mm, and heating the first plurality of particles to a temperature of between 900 C. and 1200 C. for a time period of at least 1 hour to generate a second plurality of particles that include calcium oxide.