Patent ID: 7549859

Claim:
An installation ( 11 ; 211 ; 311 ; 411 ) for calcining a mineral load containing a carbonate in order to produce a hydraulic binder, of the type comprising at least one calciner ( 29 ; 163 ), the installation successively comprising a preheater ( 27 ), at least one calciner ( 29 ) for producing a hydraulic binder comprising a combustion chamber ( 15 ) and a cooler ( 31 ); the combustion chamber ( 15 ) having: means ( 53 ) for introducing the mineral load into the chamber ( 15 ), connected to the preheater ( 27 ); combustion means ( 55 ) for maintaining the chamber ( 15 ) at a temperature between 700° C. and 900° C., the combustion means ( 55 ) having means ( 75 ) for introducing an oxidizing gas for combustion coming from the cooler ( 31 ) into the chamber ( 15 ); additional means ( 57 ) for introducing a treatment gas having a controlled carbon dioxide content into the chamber ( 15 ) in order to oppose the dissociation of the carbonate in the chamber ( 15 ); and means ( 61 ) for removing the calcined mineral load that open into the cooler ( 31 ); the installation ( 11 ; 211 ; 311 ; 411 ) comprising means ( 21 ) for discharging the flue gases coming from the or each calciner ( 29 ; 163 ) into the atmosphere; characterized in that the chamber ( 15 ) comprises means ( 51 ) for forming a fluidized bed, and in that the means ( 57 ) for introducing the treatment gas are supplied, at least partially, by at least one bypass duct ( 91 ; 93 ) with some of the flue gases, the bypass duct ( 91 ; 93 ) coming from the means for discharging the gases ( 21 ).