Magnesium phosphate cement binder systems and method for providing magnesium phosphate cements are described. In an embodiment, a magnesium phosphate cement binder system may include magnesium oxide that has been calcined at a temperature of between about 900° F. to about 1800° F. The magnesium phosphate cement binder system may also include a phosphate material. Other formulations, compositions, and methods are also described.

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.

Magnesium phosphate cement binder systems and method for providing magnesium phosphate cements are described. In an embodiment, a magnesium phosphate cement binder system may include magnesium oxide that has been calcined at a temperature of between about 900° F. to about 1800° F. The magnesium phosphate cement binder system may also include a phosphate material. Other formulations, compositions, and methods are also described.

Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.

Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.

Apparatus for the production of carbon dioxide from limestone includes a nuclear energy source (32) arranged to generate electricity and a rotary kiln (10). The rotary kiln (10) has an inlet (15) for the introduction of limestone and an outlet (19) for the release of carbon dioxide. An electrical resistance heating element (21) disposed within the kiln (10) is arranged to be supplied with electricity derived from the nuclear energy source (32) to raise the temperature of the element (21) for transfer of heat to the interior of the rotary kiln (10). Limestone in the rotary kiln (10) is thereby heated to a temperature sufficient for the release of carbon dioxide.

Apparatus for the production of carbon dioxide from limestone includes a nuclear energy source (32) arranged to generate electricity and a rotary kiln (10). The rotary kiln (10) has an inlet (15) for the introduction of limestone and an outlet (19) for the release of carbon dioxide. An electrical resistance heating element (21) disposed within the kiln (10) is arranged to be supplied with electricity derived from the nuclear energy source (32) to raise the temperature of the element (21) for transfer of heat to the interior of the rotary kiln (10). Limestone in the rotary kiln (10) is thereby heated to a temperature sufficient for the release of carbon dioxide.

A process for producing a highly calcined and uniformly calcined product from a feedstock. The process comprising the steps of grinding the feedstock to powder, preheating the powder, and calcining the powder in a reactor plant that comprises a number of reactor segments in which a flash calciner is used in each progressive reactor segment to incrementally react the powder by raising the temperature in each segment. The last segment may be a high-temperature reactor that has a controlled residence time and temperature that may allow controlled finishing of the calcination process to achieve a desired degree of calcination and sintering of the product; and cooling of the product.

A process for producing a highly calcined and uniformly calcined product from a feedstock. The process comprising the steps of grinding the feedstock to powder, preheating the powder, and calcining the powder in a reactor plant that comprises a number of reactor segments in which a flash calciner is used in each progressive reactor segment to incrementally react the powder by raising the temperature in each segment. The last segment may be a high-temperature reactor that has a controlled residence time and temperature that may allow controlled finishing of the calcination process to achieve a desired degree of calcination and sintering of the product; and cooling of the product.

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.