| abstract |
Method for calcination in an annular shaft furnace comprising a supply of material to be calcined at the top of an annular space (3) of the furnace into which the material descends, an introduction in (5) of first and in (6) of second combustion flue gases into this annular space, a discharge at the top of the furnace in (12) of an upper gas stream, a removal in (18) of a portion of the upper gas stream, a formation of a first oxidizing mixture by mixing this portion of the upper gas stream with pure dioxygen (19) and, to form the second combustion flue gases, a combustion of a fuel in this first oxidizing mixture, as well as an elimination in (20) of a lower gas stream containing the air for cooling the product, after said cooling. |