Disclosed is a clinker production plant including: a preheating unit; a calcination unit; a kiln; and a cooler. The calcination assembly includes a calcination reactor for calcination by combustion of a solid so-called alternative fuel. The calcination reactor is arranged such that at least part of the combustion fumes from the kiln pass partly through the calcination reactor before entering the preheating unit, and a tertiary gas flow including air leaving the cooler passing at least in part through the calcination reactor before entering the preheating unit. The calcination reactor includes a system for controlling the residence time of the alternative solid fuel.

A method of calcining a raw material to obtain a cementitious material, includes providing a flow of raw material containing a metal carbonate, such as CaCO.sub.3 to a calcination system, introducing the flow of raw material into a first thermal reactor and at least partially decarbonating the raw material in the first thermal reactor by subjecting the raw material to a first heat treatment at a first temperature of at least 650 C. in order to obtain an at least partly decarbonated material and CO.sub.2, wherein the first thermal reactor is heated by electrical energy, and obtaining the cementitious material as a result of the first heat treatment.

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

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

Processes and plants for producing cement clinker, in which an oxygen-containing gas having a proportion of 15% by volume or less of nitrogen and a proportion of 50% by volume or more of oxygen is conveyed from a first section of the cooler directly adjoining the top of the furnace into the rotary furnace and is optionally additionally conveyed to the calciner, and where the total gas streams fed in to the combustion processes consist to an extent of more than 50% by volume (preferably more than 85% by volume) of oxygen.

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

A calcination unit able to decarbonate raw materials intended for clinker production, the unit including: a main duct in which the raw materials circulate according to a first movement direction, the raw materials being calcined in the main duct; a solid fuel supply duct opening onto the main duct via a fuel outlet, the solid fuel moving according to a second movement direction; a retaining device located in the main duct and arranged opposite the solid fuel outlet so that the solid fuel arriving in the main duct via the fuel outlet passes through the retaining device.

In methods of and/or plants for manufacturing cement clinker, the amount of chloride bypass exhaust gas 79 can be substantially decreased, when using previously cooled chloride bypass exhaust gas 81 and/or cooled kiln exhaust gas as coolant for the chloride bypass exhaust gas 39 prior to deducting the chloride bypass exhaust gas 39.

In methods of and/or plants for manufacturing cement clinker, the amount of chloride bypass exhaust gas 79 can be substantially decreased, when using previously cooled chloride bypass exhaust gas 81 and/or cooled kiln exhaust gas as coolant for the chloride bypass exhaust gas 39 prior to deducting the chloride bypass exhaust gas 39.

A method for the cooling of and heat recovery from materials at very high temperatures is disclosed. The method includes a) conveying material at very high temperature into a mixing system, b) transporting the material exiting the mixing system inside a continuous-flow channel, c) recovering heat from the transported material, d) feeding a flow of material exiting at low temperature from the continuous-flow channel to a flow dividing system, e) recovering a part of the low-temperature material exiting the flow dividing system, f) moving the part of recovered material at low temperature by means of a moving and recirculating system, and g) conveying the material at low temperature for mixing with the material at the very high temperature in the mixing system.