A process for producing cement clinker may involve preheating raw meal in a preheater, calcining the preheated raw meal in a calciner, burning the preheated and calcined raw meal in a furnace to give cement clinker, cooling the cement clinker in a cooler, branching off a portion of the furnace offgases flowing out of the furnace as bypass gas, cooling the bypass gas in a mixing chamber with a cooling gas, and separating out dust present in the bypass gas. The cooling gas is formed at least partly or completely from the bypass gas and/or the calciner offgas and/or the preheater offgas. The cooling gas is introduced into the mixing chamber in a ratio of 2-10:1 relative to the bypass gas.

A cement production plant may include a preheater for preheating raw meal, a calciner for calcining the preheated raw meal, and a furnace with a furnace burner for firing the raw meal to form cement clinker. The furnace has a combustion gas inlet for admitting a combustion gas with an oxygen content of 30% to 75% into the furnace. The cement production plant may also include a cooler for cooling the cement clinker. The calciner and the furnace each have at least one respective fuel inlet for admitting at least one fuel into the calciner and the furnace. The calciner and the furnace each have at least one respective inert gas inlet for respectively admitting inert gas into the calciner and the furnace.

Provided herein are compositions, methods, and systems related to 3D printing a reactive vaterite cement composition, comprising feeding a composition comprising reactive vaterite cement through a 3D printing machine; printing a 3D printed reactive vaterite cement product; and curing the 3D printed reactive vaterite cement product by transforming reactive vaterite cement in the 3D printed reactive vaterite cement product to aragonite and/or calcite during and/or after the curing.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods makes use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods makes use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods makes use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods makes use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

A cement clinker producing system, capable of providing a gas containing a carbon dioxide gas at a high concentration by increasing a carbon dioxide gas concentration for a part of an exhaust gas, includes a cyclone preheater to preheat a cement clinker raw material, a rotary kiln to burn the preheated cement clinker raw material so as to provide cement clinker, a calcination furnace to promote decarbonation of the cement clinker raw material, a clinker cooler to cool the cement clinker, a kiln exhaust-gas discharge passages to discharge an exhaust gas generated in the rotary kiln, a combustion-supporting gas supply device to supply a combustion-supporting gas having a higher oxygen concentration than air, a combustion-supporting gas supply passage to guide the combustion-supporting gas to the calcination furnace, and a calcination furnace exhaust-gas discharge passage to discharge a carbon dioxide gas-containing exhaust gas generated in the calcination furnace.

Processes and plants for producing cement clinker, wherein no recirculation of preheater exhaust gases occurs and the ratio of solid fed in to exhaust gas in the preheater is set to greater than 1.0 kg of solid to gas.

A method for the thermal treatment of clays by: preheating the clay, which is suspended in a carrier gas, in a heat exchanger; thermally treating the clay in a calcination stage operated under chemically oxidizing conditions; subsequently thermally treating the clay in a calcination stage operated under chemically reducing conditions; cooling the clay in a cooling stage operated under chemically reducing conditions; cooling the clay in a cooling stage operating under chemically oxidizing conditions.