A process for the manufacturing of a cement substitute may include: mixing an alkaline aluminosilicate containing material with at least one aluminosilicate hydrate containing material, and heating the thus obtained mixture to a calcination temperature of below 800 C. to form a calcined product comprising a reactive amorphous phase having the alkali ions bound therein. The process may further comprise a step of cooling the calcined product to a desired temperature. A cement substitute is obtainable by this process. The cement substitute includes a reactive amorphous phase of co-calcined alkali aluminosilicate containing material and aluminosilicate hydrate, containing material having alkali ions bound therein. The alkali ions are preferably sodium ions.

The invention relates to a plant and to a method for the production of cement clinker from cement raw meal, the cement raw meal being preheated in a preheating zone, precalcined in a calcining zone, completely burned in a sintering combustion zone and cooled in a cooling zone, solid fuels additionally being burned in an additional combustion region, a firing region being used in the additional combustion region, the solid fuel being introduced into the firing region where it forms a fuel bed over which a supplied oxygen-containing gas flows, the resulting combustion products being removed via a discharge opening and being used in the production of cement clinker. The fuel is supplied via a conveyor device arranged outside the firing region, in such a manner that it moves the fuel bed that is present in the direction towards the discharge opening.

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.

By preparing a raw material mixture comprising CaO raw material, SiO.sub.2 raw material and waste material, and having a content of Al.sub.2 O.sub.3 after heating at 1000 C. of 5.0 mass % or less, and calcining at a calcination temperature of 1350 C. to 1600 C., it is possible to efficiently use waste materials as a part of raw materials, and to obtain a calcined product that comprises almost an equivalent amount of -2CaO.Math.SiO.sub.2 as conventional can be obtained.

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.

The invention relates to a method and a system for producing cement clinker from raw cement mixture, wherein one part of the raw cement mixture is preheated in a calciner preheater, and the other part of the raw cement mixture is preheated in an oven preheater, the preheated raw cement mixture is pre-calcined in a calciner which is operated according to the oxyfuel method, the pre-calcined raw cement mixture is fired in an oven, the fired raw cement mixture is cooled in a cooler, the calciner preheater is operated using exhaust gases of the calciner, the oven preheater is operated using exhaust gases of the oven, an entrained flow reactor is used as the calciner, a part of the calciner exhaust gas being recirculated to the calciner after being used in the calciner preheater, and the oven exhaust gas undergoes a post-combustion CO.sub.2 separation.

The invention relates to a method and a system for producing cement clinker from raw cement mixture, wherein one part of the raw cement mixture is preheated in a calciner preheater, and the other part of the raw cement mixture is preheated in an oven preheater, the preheated raw cement mixture is pre-calcined in a calciner which is operated according to the oxyfuel method, the pre-calcined raw cement mixture is fired in an oven, the fired raw cement mixture is cooled in a cooler, the calciner preheater is operated using exhaust gases of the calciner, the oven preheater is operated using exhaust gases of the oven, an entrained flow reactor is used as the calciner, a part of the calciner exhaust gas being recirculated to the calciner after being used in the calciner preheater, and the oven exhaust gas undergoes a post-combustion CO.sub.2 separation.

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 method of manufacture of Portland cement clinker is described in a dry process that captures the carbon dioxide emitted from the calcination of carbonate minerals, principally limestone. The process uses an indirectly heated, counter-flow reactor to pre-heat and calcine the cement meal to produce a separate calcined meal and carbon dioxide gas stream, with external heat being provided by the combustion of a secondary fuel stream with pre-heated air. This calcined meal is injected into the conventional rotary kiln, where the hot flue gas from combustion of the primary fuel with pre-heated air is used to fuse, react and sinter the powders to form granules of cement clinker. The clinker and carbon dioxide streams are cooled by the air pre-heaters.

A method for calcination of a carbon dioxide rich sorbent (containing CaCO.sub.3) includes combusting in a furnace a fuel with an oxidizer, supplying heat transfer (HT) solids into the furnace and heating them, transferring the HT solid particles from the furnace to a reactor having a rotatable container, supplying a carbon dioxide rich solid sorbent (containing CaCO.sub.3) into the rotatable container, rotating the rotatable container for mixing the solid particles and the carbon dioxide rich solid sorbent for transferring heat from the solid particles to the carbon dioxide rich solid sorbent and generating carbon dioxide and carbon dioxide lean solid sorbent (mainly CaO), discharging the carbon dioxide and the carbon dioxide lean solid sorbent from the rotatable container and the subsequent classification of the HT solids from the lean sorbent.