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 make 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 make 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 process for producing cement clinker, may involve preheating raw meal in a preheater, calcining the preheated raw meal in a calciner, and burning the preheated and calcined raw meal in a furnace to give cement clinker. The furnace may be supplied with a combustion gas having an oxygen content, and the temperature within the furnace is ascertained. The process may involve cooling the cement clinker in a cooler. The oxygen supply to the furnace is under closed-loop control as a function of the temperature ascertained within the furnace. The temperature ascertained is compared with a target value and, in the event of any variance of the temperature ascertained from the target value, the oxygen supply to the furnace and/or to the calciner is increased or decreased. The target value is adjusted depending on a particle size distribution and/or a lime standard.

A process for producing cement clinker, may involve preheating raw meal in a preheater, calcining the preheated raw meal in a calciner, and burning the preheated and calcined raw meal in a furnace to give cement clinker. The furnace may be supplied with a combustion gas having an oxygen content, and the temperature within the furnace is ascertained. The process may involve cooling the cement clinker in a cooler. The oxygen supply to the furnace is under closed-loop control as a function of the temperature ascertained within the furnace. The temperature ascertained is compared with a target value and, in the event of any variance of the temperature ascertained from the target value, the oxygen supply to the furnace and/or to the calciner is increased or decreased. The target value is adjusted depending on a particle size distribution and/or a lime standard.

A method for reducing combustion temperature and/or thermal radiation within a lime kiln of a pulp production plant, which kiln is a rotary kiln having a kiln tube (1) internally covered with refractory tiles (13) and having a burner (2) supplied by fuel for heating of the rotary kiln by a flame (3). The effects are achieved by supplying calcium carbonate containing particles to the flame (3) and/or to surrounding area around the flame (3). The particles are supplied into the rotary kiln by at least one lance (9) to the upper part of the flame (3). Calcium oxide containing particles may be supplied to the rotary kiln to areas surrounding the flame (3) for reducing the thermal radiation to an area over the flame (3) and/or to the area at the side of the flame (3), where the refractory tiles (13) of the kiln are rotating downwards.

High alumina cement is produced in a submerged combustion melter, cooled and ground.

Method of operating a long direct-fired inclined counterflow rotary kiln for the thermal treatment of material and counterflow rotary kiln adapted for same, whereby material to be treated is introduced into the kiln at the inlet end and treated material is evacuated from the kiln at the outlet end, whereby a main combustion zone extends inside the kiln over a distance of ¼ to ⅓ of the internal length L.sub.int of the kiln, whereby a supplementary combustion zone in which supplementary combustion takes place with an oxygen-rich oxidant extends inside the kiln over a distance from the inlet end of at most ¼ of the internal length L.sub.int, and whereby no combustion takes place in a heat exchange zone located between the main combustion zone and the supplementary combustion zone.

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 make 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.

Embodiments described herein relate to capturing and sequestering CO.sub.2 emissions from the cement production process with the potential to produce carbon-negative cement. Methods described herein can include contacting calcium oxide (CaO) with ambient air at a carbonation station to form a first stream of calcium carbonate, combining the first stream of calcium carbonate with a second stream of calcium carbonate in a calciner to form a combined stream of calcium carbonate, and applying heat to the calciner to decompose the combined stream of calcium carbonate into a stream of calcium oxide and a CO.sub.2 stream. The method further includes sequestering the CO.sub.2 stream, dividing the stream of calcium oxide into a first calcium oxide stream and a second calcium oxide stream, feeding the first stream of calcium oxide to the carbonation station, and feeding the second stream of calcium oxide to a kiln to produce a clinker.

The present disclosure is related to the field of steel slag treatment, and in particular to a process for stabilizing steel slag, the process comprising subjecting the steel slag to an autoclave treatment by use of a high temperature and pressure saturated vapor at a pressure of 2.0 MPa or above. The process provides the slag with reliable volume stability and makes it possible to meet desired requirements of various building materials. Additionally, the process is low cost, non-polluting, and of very high industrial value.